# US 2023/0054022 A1 · Method for producing polyamide resin film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0054022 A1 - Document ID: US20230054022A1 - Status: Published application - Kind: A1 - Application number: 17/794,030 - Filed: 2021-01-22 - Published: 2023-02-23 - Earliest claimed: 2020-01-24 - Assignees: Unitika Ltd. - Applicants: Unitika Ltd. - Inventors: Akiko Kurosawa; Atsuko Noda - Web page: https://patentgrep.com/patent/US20230054022A1 ## CPC - C08G 69/14: Lactams - C08J 5/18: Manufacture of films or sheets - B29C 55/005: {characterised by the choice of materials} - B29C 55/12: biaxial - B32B 27/34: comprising polyamides - C08J 11/10: by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation (depolymerisation to the original monomer C07) - C08L 77/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08L77/10 takes precedence) - B32B 2272/00: Resin or rubber layer comprising scrap, waste or recycling material - B32B 2305/70: Scrap or recycled material - B32B 2307/518: bi-axially - B32B 2307/704: Crystalline - B32B 2307/75: Printability - B32B 2439/00: Containers; Receptacles - C08J 2377/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08J2377/10 takes precedence) - C08J 2477/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08J2477/10 takes precedence) - C08L 2207/20: Recycled plastic - Y02P 20/143: the feedstock being recycled material, e.g. plastics - Y02W 30/62: Plastics recycling; Rubber recycling - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - 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) - 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) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract To provide a method for producing a polyamide resin film by using a polyamide resin obtained through polymerization of a regenerated monomer used as a recycled material. Provided is a method for producing a polyamide resin film, including: (1) a step of producing a monomer from a raw material (A) for depolymerization, (2) a step of producing a polyamide resin (B) through polymerization using a raw material containing the monomer. (3) a step of refining the polyamide resin (B), and (4) a step of producing an unstretched film using a starting material containing the refined polyamide resin (B), and stretching the unstretched film. ## Claims ### Claim 1 A method for producing a polyamide resin film, the method comprising: (1) a step of producing a monomer from a raw material (A) for depolymerization; (2) a step of producing a polyamide resin (B) through polymerization using a raw material containing the monomer, (3) a step of refining the polyamide resin (B); and (4) a step of producing an unstretched film using a starting material containing the refined polyamide resin (B), and stretching the unstretched film. ### Claim 2 (depends on 1) The production method according to claim 1, wherein the monomer contains ε-caprolactam. ### Claim 3 (depends on 1) The production method according to claim 1, further comprising a step of adjusting a moisture content in an unstretched film to 2 to 10 mass % in advance, prior to stretching. ### Claim 4 (depends on 1) The production method according to claim 1, wherein starting materials partly contain a remelted resin obtained by melting a polyamide resin (provided that the polyamide resin (B) is excluded) and a content of the remelted resin is 1 mass % or more. ### Claim 5 (depends on 1) The production method according to claim 1, wherein the refined polyamide resin (B) has a relative viscosity ηR of 2.5 to 4.5. ### Claim 6 (depends on 1) The production method according to claim 1, wherein the raw material (A) for depolymerization is at least one of a polyamide 6 resin and an oligomer thereof. ### Claim 7 A polyamide resin film, wherein, when the film is halftone-printed, the polyamide resin film includes 100 or fewer missing dots in 1000 mm2 of a 10% gradation part in a halftone-printed film. ### Claim 8 (depends on 7) The polyamide resin film according to claim 7, which has a caprolactam monomer concentration of 1.6 mass % or less in the polyamide resin film. ### Claim 9 (depends on 7) The polyamide resin film according to claim 7, wherein a terminal amino group content and a terminal carboxyl group content in the polyamide resin film are each 80 mmol/kg or less. ### Claim 10 (depends on 7) The polyamide resin film according to claim 7, which has a ratio of a minimum of film impact strength to a maximum of film impact strength under an atmosphere at a temperature of 23° C. and a humidity of 0.5 to 1.0. ### Claim 11 (depends on 7) The polyamide resin film according to claim 7, which comprises a polyamide resin that shows a half width of 10° C. or more of a crystallization peak during cooling. ### Claim 12 (depends on 7) The polyamide resin film according to claim 7, which is biaxially stretched. ### Claim 13 (depends on 7) A laminated film comprising the polyamide resin film according to claim 7, and a sealant resin layer laminated on the polyamide resin film. ### Claim 14 (depends on 7) A packaging material comprising the polyamide resin film according to claim 7. ### Claim 15 (depends on 1) A polyamide resin film obtained by the method according to claim 1. ### Claim 16 (depends on 8) A laminated film comprising the polyamide resin film according to claim 8, and a sealant resin layer laminated on the polyamide resin film. ### Claim 17 (depends on 9) A laminated film comprising the polyamide resin film according to claim 9, and a sealant resin layer laminated on the polyamide resin film. ### Claim 18 (depends on 8) A packaging material comprising the polyamide resin film according to claim 8. ### Claim 19 (depends on 9) A packaging material comprising the polyamide resin film according to claim 9. ### Claim 20 (depends on 2) A polyamide resin film obtained by the method according to claim 2.