Process for recycling waste film and product made therefrom
The present disclosure is directed to a process for recycling film materials, and is particularly directed to collecting spent release liners for labels and constructing new release liner stock from the spent materials. In order to use the waste film, the film is subjected to a process for increasing the intrinsic viscosity. In addition, a coloring agent may be incorporated into the film in order to mask yellowing. In one embodiment, a multilayered composite film is formed.
1. A process for producing a release liner comprising,
reducing spent liner stock into chips, the spent liner stock having an intrinsic viscosity;
increasing the intrinsic viscosity of the liner stock chips to from about 0.58 to about 0.7;
combining the liner stock with a coloring agent; and
heating and extruding the liner stock into a film, the film having a release surface configured to function as a release liner for a laminate material.
2. A process as defined in claim 1 , wherein the spent liner stock comprises a polyethylene terephthalate polymer.
3. A process as defined in claim 1 , wherein the coloring agent comprises a green or blue coloring agent for producing a green colored film.
4. A process as defined in claim 1 , wherein the film has a yellowness index of less than about 1.25.
5. A process as defined in claim 1 , wherein the intrinsic viscosity of the spent liner stock chips is increased through solid state polymerization.
6. A process as defined in claim 1 , wherein the intrinsic viscosity of the spent liner stock chips is increased to from about 0.6 to about 0.64.
7. A process as defined in claim 1 , further comprising the step of laminating the film to a laminate material.
8. A process as defined in claim 7 , wherein the laminate material comprises a label.
9. A process as defined in claim 1 , wherein the extruded film comprises a multilayered film, the multilayered film including at least a middle layer positioned in between a first outer layer and a second outer layer, the liner stock being completely contained within the middle layer.
10. A process as defined in claim 9 , wherein the layers of the film are coextruded.
11. A process as defined in claim 9 , wherein the first outer layer and the second outer layer contain virgin polyethylene terephthalate polymer.
12. A process as defined in claim 11 , wherein the middle layer comprises the liner stock combined with virgin polyethylene terephthalate polymer.
13. A process as defined in claim 12 , wherein at least 1% by weight of the middle layer comprises the liner stock.
14. A process as defined in claim 1 , wherein the coloring agent comprises a pigment dispersion and is contained within the film in an amount less than about 1% by weight.
15. A process as defined in claim 1 , wherein the release surface on the film is formed by applying a release coating to the film.
16. A process as defined in claim 15 , wherein the release coating comprises a silicone coating.
17. A process as defined in claim 13 , wherein the first outer layer and the second outer layer each comprise from about 5% to about 15% by weight of the coextruded film, the middle layer comprising from about 70% to about 90% by weight of the coextruded film, the middle layer containing the liner stock in an amount of from about 1% to about 100% by weight.
18. A process as defined in claim 1 , wherein the intrinsic viscosity of the spent liner stock chips is increased to from about 0.61 to about 0.63.
19. A process as defined in claim 1 , wherein the spent liner stock comprises a polyester polymer and wherein the intrinsic viscosity of the liner stock is increased by incorporating a chain extender into the polyester polymer.
20. A process as defined in claim 1 , further comprising a step of biaxially stretching the film during formation of the film.
21. A process as defined in claim 1 , further comprising the step of pelletizing the spent liner stock prior to increasing the intrinsic viscosity of the liner stock chips.
22. A process for producing a release liner comprising:
reducing spent liner stock into chips, the spent liner stock having an intrinsic viscosity;
increasing the intrinsic viscosity of the liner stock chips through solid state polymerization;
combining the liner stock with a coloring agent; and
heating and extruding the liner stock into a film, the film having a release surface configured to function as a release liner for a laminate material.
23. A process as defined in claim 22 , wherein the intrinsic viscosity of the liner stock chips is increased to from about 0.58 to about 0.7.
24. A process as defined in claim 22 , wherein the spent liner stock comprises a polyethylene terephthalate polymer.
25. A process as defined in claim 22 , wherein the extruded film comprises a multilayered film, the multilayered film including at least a middle layer positioned in between a first outer layer and a second outer layer, the liner stock being completely contained within the middle layer.