Configuration of multiple thermoformable film layers for rigid packaging requiring moisture and oxygen protection
View Patent ↗A four-layer film for packaging, including blister packaging, is described. Layer 1 may be a rigid film, such as a polyvinyl chloride (PVC) or polyester. Layer 2 may be a moisture barrier, such as polychlorotrifluoroethylene (PCTFE). Layer 3 may be an oxygen barrier, such as a co-extruded film having a polyethylene (PE) layer, an EVOH layer, and a second PE layer. Layer 4 may be a relatively thin layer of a rigid film, such as a PVC or polyester. In this arrangement, Layer 2 may protect the contents of the package from external or atmospheric moisture. Layer 2 may also protect Layer 3 from atmospheric moisture, thereby helping to preserve the effectiveness of Layer 3 as an oxygen barrier.
1. A film comprising:
a first layer consisting essentially of at least one of polyvinyl chloride and polyester;
a second layer consisting essentially of polychlorotrifluoroethylene;
a third layer comprising
a first sublayer consisting essentially of polyethylene,
a second sublayer consisting essentially of ethylene vinyl alcohol copolymer, and
a third sublayer consisting essentially of polyethylene; and
a fourth layer consisting essentially of at least one of polyvinyl chloride and polyester, the fourth layer comprising a higher gloss side and a lower gloss side.
2. The film of claim 1 , wherein the first layer provides at east 25% and no more than 50% of a total thickness of the film.
3. The film of claim 1 , wherein the first layer is 127 microns±5% thick, the second layer is 102 microns±15% thick, the third layer is 51 microns±15% thick, and the fourth layer is 60 microns±10% thick.
4. The film of claim 1 , wherein the third layer is a coextruded film.
5. The film of claim 1 , wherein the fourth layer is a calendered film.
6. The film of claim 1 , wherein the higher gloss side of the fourth layer is 27 to 77 gloss units glossier than the lower gloss side of the fourth layer.
7. The film of claim 1 , wherein the higher gloss side of the fourth layer is oriented toward the third layer.
8. A method of making a film comprising:
providing a first layer consisting essentially of at least one of polyvinyl chloride and polyester;
attaching a second layer consisting essentially of polychlorotrifluoroethylene to the first layer;
attaching a third layer to the second layer, the third layer comprising
a first sublayer consisting essentially of polyethylene,
a second sublayer consisting essentially of ethylene vinyl alcohol copolymer, and
a third sublayer consisting essentially of polyethylene; and
attaching a fourth layer to the third layer, the fourth layer consisting essentially of at least one of polyvinyl chloride and polyester, the fourth layer comprising a higher gloss side and a lower gloss side.
9. The method of claim 8 , wherein the first layer provides at least 25% and no more than 50% of a total thickness of the film.
10. The method of claim 8 , wherein the first layer is 127 microns±5% thick, the second layer is 102 microns±15% thick, the third layer is 51 microns±15% thick, and the fourth layer is 60 microns±10% thick.
11. The method of claim 8 , further comprising forming the third layer by co-extrusion.
12. The method of claim 8 , further comprising forming the fourth layer by calendering.
13. The method of claim 8 , wherein the higher gloss side of the fourth layer is 27 to 77 gloss units glossier than the lower gloss side of the fourth layer.
14. The method of claim 8 , wherein the higher gloss side of the fourth layer is oriented toward the third layer.
15. The method of claim 12 , further comprising
contacting the higher gloss side of the fourth layer with a hotter calender roll; and
contacting the lower gloss side of the fourth layer with a cooler calender roll.
16. The method of claim 15 , wherein the hotter calendar roll is a final roll to contact the higher gloss side.
17. The method of claim 15 , wherein the cooler calendar roll is a final roll to contact the lower gloss side.
18. The method of claim 15 , wherein the hotter calendar roll is at least 18° C. and no more than 32° C. hotter than the cooler calender roll.
19. A film comprising:
a first layer of consisting essentially of at least one of polyvinyl chloride and polyester;
a second layer consisting essentially of polychlorotrifluoroethylene;
a third layer comprising
a first sublayer consisting essentially of polyethylene,
a second sublayer consisting essentially of ethylene vinyl alcohol copolymer, and
a third sublayer consisting essentially of polyethylene.
20. The film of claim 19 , wherein the first layer is 127 microns±5% thick, the second layer is 102 microns±15% thick, the third layer is 51 microns±15% thick, and the fourth layer is 60 microns±10% thick.