# US 12,179,978 B2 · Laminating film resistant to discoloration caused by cooking, and film-laminated metal sheet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,179,978 B2 - Document ID: US12179978B2 - Status: Granted - Kind: B2 - Application number: 17/277,479 - Filed: 2019-09-19 - Published: 2021-11-11 - Granted: 2024-12-31 - Earliest claimed: 2018-09-19 - Assignees: Baoshan Iron & Steel Co., Ltd. - Applicants: Baoshan Iron & Steel Co., Ltd. - Inventors: Long Xie; Zhangwei Wang; Hua Ni; Xiujun Li; Hongxing Chen - Web page: https://patentgrep.com/patent/US12179978B2 ## CPC - B65D 65/40: Applications of laminates for particular packaging purposes {(B65D1/0215, B65D1/28, B65D3/22, B65D5/0281, B65D5/563, B65D9/30, B65D29/02, B65D31/02, B65D75/26, B65D77/2024, B65D81/1275, B65D81/3811, B65D81/3823, B65D81/3834, B65D81/3846, B65D81/3858, B65D81/3874, B65D81/3886, B65D81/3897 take precedence; laminates per se or laminated packages characterised by the composition or)} - B29C 48/0018: {combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence)} - B29C 48/0021: {combined with joining, lining or laminating} - B29C 48/022: {characterised by the choice of material} - B29C 48/08: flexible, e.g. films - B29C 48/154: Coating solid articles, i.e. non-hollow articles - B29C 48/21: the layers being joined at their surfaces - B32B 15/08: of synthetic resin - B32B 15/09: comprising polyesters - B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} - B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} - B32B 27/08: of synthetic resin - B32B 27/18: characterised by the use of special additives - B32B 27/20: using fillers, pigments, thixotroping agents - B32B 27/36: comprising polyesters - B65D 7/42: {Details of metal walls (casks, barrels or drums in their entirety B65D7/045; other container details B65D23/00, B65D25/00)} - C08J 5/18: Manufacture of films or sheets - C08K 3/36: Silica - C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence) - B29K 2067/003: {PET, i.e. poylethylene terephthalate} - B29K 2067/006: {PBT, i.e. polybutylene terephthalate} - B29K 2105/0088: {Blends of polymers} - B29K 2509/08: Glass - B32B 2250/03: 3 layers - B32B 2250/04: 4 layers - B32B 2250/244: All polymers belonging to those covered by group B32B27/36 - B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA - B32B 2255/06: on metal layer - B32B 2255/205: Metallic coating - B32B 2264/101: Glass - B32B 2264/102: Oxide or hydroxide - B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers - B32B 2307/30: having particular thermal properties - B32B 2307/306: Resistant to heat - B32B 2307/308: Heat stability - B32B 2307/40: having particular optical properties - B32B 2307/518: bi-axially - B32B 2307/704: Crystalline - B32B 2307/714: Inert, i.e. inert to chemical degradation, corrosion - B32B 2307/732: Dimensional properties - B32B 2307/752: Corrosion inhibitor - B32B 2439/66: Cans, tins - B32B 2439/70: Food packaging - C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) - C08J 2467/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08J2467/06 takes precedence) - C08L 2203/16: used for films - C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure - B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES - 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 - 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) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS ## Abstract A blended polyester laminating film resistant to discoloration caused by cooking, comprising polyethylene terephthalate and polybutylene terephthalate. The blended polyester laminating film comprises three layers, i.e., upper, middle, and lower layers. One surface layer contains SiO2 in a mass fraction of 1200-2000 ppm added by in-situ polymerization. The blended polyester laminating film is manufactured by a three-layer coextrusion biaxial stretching method, and the manufacturing method is 240-275° C. A film-laminated metal sheet manufactured from the blended polyester laminating film has excellent resistance to discoloration caused by cooking, and is applied to metal containers for food and beverage packaging that require high-temperature sterilization. ## Claims ### Claim 1 A blended polyester steel-laminating film resistant to cooking discoloration, wherein the blended polyester steel-laminating film comprises polyethylene terephthalate and polybutylene terephthalate, wherein the blended polyester steel-laminating film comprises three layers including an upper layer, an intermediate layer, and a lower layer, wherein the upper layer or the lower layer comprises 1200-2000 ppm by mass of SiO2 added by in-situ polymerization, and wherein each of the upper layer, the intermediate layer, and the lower layer comprises the polyethylene terephthalate and the polybutylene terephthalate with a mass ratio from 6:4 to 4:6, and the mass ratios of the polyethylene terephthalate to the polybutylene terephthalate in each layer are the same or different. ### Claim 2 (depends on 1) The blended polyester steel-laminating film according to claim 1, wherein the upper layer or the lower layer comprises 1800 ppm by mass of SiO2 added by in-situ polymerization. ### Claim 3 (depends on 1) The blended polyester steel-laminating film resistant to cooking discoloration according to claim 1, wherein the polyethylene terephthalate has a melting point of 250-265° C., and the polybutylene terephthalate has a melting point of 220-235° C. ### Claim 4 (depends on 1) The blended polyester steel-laminating film resistant to cooking discoloration according to claim 1, wherein a mass ratio of the polyethylene terephthalate to the polybutylene terephthalate is 6:4, 5:5 or 4:6. ### Claim 5 (depends on 1) The blended polyester steel-laminating film resistant to cooking discoloration according to claim 1, wherein the blended polyester steel-laminating film has a thickness of 12-35 um. ### Claim 6 (depends on 1) A method of manufacturing the blended polyester steel-laminating film resistant to cooking discoloration according to claim 1, wherein the method comprises forming a homogeneous mixture of the polyethylene terephthalate and the polybutylene terephthalate into the blended polyester steel-laminating film by a three-layer coextrusion biaxial stretching process. ### Claim 7 (depends on 6) The method of manufacturing the blended polyester steel-laminating film resistant to cooking discoloration according to claim 6, wherein the blended polyester steel-laminating film is manufactured at a temperature of 240-275° C. ### Claim 8 (depends on 1) A film-laminated metal plate, wherein the film-laminated metal plate comprises a metal substrate and the blended polyester steel-laminating film according to claim 1. ### Claim 9 (depends on 8) The film-laminated metal plate according to claim 8, wherein the metal substrate is selected from the group consisting of a chromium-plated steel plate, a tin-plated steel plate, a low-tin steel plate, a galvanized steel plate, a cold-rolled steel plate, a stainless steel plate, and an aluminum plate. ### Claim 10 (depends on 8) The film-laminated metal plate according to claim 8, wherein a skin layer of the blended polyester steel-laminating film that comprises 1200-2000 ppm by mass of SiO2 added by in-situ polymerization is a layer that is not in contact with the metal substrate. ### Claim 11 (depends on 8) A method of manufacturing the film-laminated metal plate according to claim 8, wherein the method comprises thermal lamination of the blended polyester steel-laminating film on a surface of the metal substrate by hot melt lamination at a pressure of 2-10 kg and a temperature of 180-260° C. ### Claim 12 (depends on 8) A film-laminated metal can for food or beverage packaging, wherein the film-laminated metal can is made of the film-laminated metal plate according to claim 8. ### Claim 13 (depends on 12) The film-laminated metal can according to claim 12, wherein the metal substrate of the film-laminated metal plate is selected from the group consisting of a chromium-plated steel plate, a tin-plated steel plate, a low-tin steel plate, a galvanized steel plate, a cold-rolled steel plate, a stainless steel plate, and an aluminum plate. ### Claim 14 (depends on 12) The film-laminated metal can according to claim 12, wherein in the film-laminated metal plate, a skin layer of the blended polyester steel-laminating film that comprises 1200-2000 ppm by mass of SiO2 added by in-situ polymerization is a layer that is not in contact with the metal substrate. ### Claim 15 (depends on 8) The film-laminated metal plate according to claim 8, wherein the upper layer or the lower layer of the blended polyester steel-laminating film comprises 1800 ppm by mass of SiO2 added by in-situ polymerization. ### Claim 16 (depends on 8) The film-laminated metal plate according to claim 8, wherein: the polyethylene terephthalate of the blended polyester steel-laminating film has a melting point of 250-265° C., and the polybutylene terephthalate has a melting point of 220-235° C.; and/or a mass ratio of the polyethylene terephthalate to the polybutylene terephthalate in the blended polyester steel-laminating film ranges from 6:4 to 4:6; and/or the blended polyester steel-laminating film has a thickness of 12-35 um. ### Claim 17 (depends on 12) The method of manufacturing the film-laminated metal plate according to claim 12, wherein the upper layer or the lower layer of the blended polyester steel-laminating film comprises 1800 ppm by mass of SiO2 added by in-situ polymerization. ### Claim 18 (depends on 11) The method of manufacturing the film-laminated metal plate according to claim 11, wherein: the polyethylene terephthalate of the blended polyester steel-laminating film has a melting point of 250-265° C., and the polybutylene terephthalate has a melting point of 220-235° C.; and/or a mass ratio of the polyethylene terephthalate to the polybutylene terephthalate in the blended polyester steel-laminating film ranges from 6:4 to 4:6; and/or the blended polyester steel-laminating film has a thickness of 12-35 um; and/or the metal substrate is selected from the group consisting of a chromium-plated steel plate, a tin-plated steel plate, a low-tin steel plate, a galvanized steel plate, a cold-rolled steel plate, a stainless steel plate, and an aluminum plate. ### Claim 19 (depends on 12) The film-laminated metal can according to claim 12, wherein: the polyethylene terephthalate of the blended polyester steel-laminating film has a melting point of 250-265° C., and the polybutylene terephthalate has a melting point of 220-235° C.; and/or a mass ratio of the polyethylene terephthalate to the polybutylene terephthalate in the blended polyester steel-laminating film ranges from 6:4 to 4:6; and/or the blended polyester steel-laminating film has a thickness of 12-35 um.