# US 8,465,614 B2 · Process for recycling waste film and product made therefrom > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,614 B2 - Document ID: US8465614B2 - Status: Granted - Kind: B2 - Application number: 13/005,171 - Filed: 2011-01-12 - Published: 2011-07-14 - Granted: 2013-06-18 - Earliest claimed: 2010-01-13 - Assignees: Mitsubishi Polyester Film GmbH - Applicants: Marshall Dean Ledbetter; Kathleen L. Trojan - Inventors: Marshall Dean Ledbetter; Kathleen L. Trojan - Web page: https://patentgrep.com/patent/US8465614B2 ## CPC - B29C 48/08: flexible, e.g. films - B29C 48/022: {characterised by the choice of material} - B29C 48/17: the components having different colours - B29C 48/793: upstream of the plasticising zone, e.g. heating in the hopper - B29C 65/00: Joining {or sealing} of preformed parts {, e.g. welding of plastics materials}; Apparatus therefor {(general aspects of processes or apparatus for joining preformed parts B29C66/00; using porous material formed by internal pressure generated therein for joining preformed parts B29C44/1228, B29C44/326)} - C08J 11/06: without chemical reactions - C09J 7/40: characterised by release liners - C09J 2483/005: in the release coating - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) ## Abstract 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) A process as defined in claim 1, wherein the spent liner stock comprises a polyethylene terephthalate polymer. ### Claim 3 (depends on 1) A process as defined in claim 1, wherein the coloring agent comprises a green or blue coloring agent for producing a green colored film. ### Claim 4 (depends on 1) A process as defined in claim 1, wherein the film has a yellowness index of less than about 1.25. ### Claim 5 (depends on 1) A process as defined in claim 1, wherein the intrinsic viscosity of the spent liner stock chips is increased through solid state polymerization. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 1) A process as defined in claim 1, further comprising the step of laminating the film to a laminate material. ### Claim 8 (depends on 7) A process as defined in claim 7, wherein the laminate material comprises a label. ### Claim 9 (depends on 1) 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. ### Claim 10 (depends on 9) A process as defined in claim 9, wherein the layers of the film are coextruded. ### Claim 11 (depends on 9) A process as defined in claim 9, wherein the first outer layer and the second outer layer contain virgin polyethylene terephthalate polymer. ### Claim 12 (depends on 11) A process as defined in claim 11, wherein the middle layer comprises the liner stock combined with virgin polyethylene terephthalate polymer. ### Claim 13 (depends on 12) A process as defined in claim 12, wherein at least 1% by weight of the middle layer comprises the liner stock. ### Claim 14 (depends on 1) 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. ### Claim 15 (depends on 1) A process as defined in claim 1, wherein the release surface on the film is formed by applying a release coating to the film. ### Claim 16 (depends on 15) A process as defined in claim 15, wherein the release coating comprises a silicone coating. ### Claim 17 (depends on 13) 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. ### Claim 18 (depends on 1) 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. ### Claim 19 (depends on 1) 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. ### Claim 20 (depends on 1) A process as defined in claim 1, further comprising a step of biaxially stretching the film during formation of the film. ### Claim 21 (depends on 1) 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. ### Claim 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. ### Claim 23 (depends on 22) 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. ### Claim 24 (depends on 22) A process as defined in claim 22, wherein the spent liner stock comprises a polyethylene terephthalate polymer. ### Claim 25 (depends on 22) 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.