# US 11,111,350 B2 · Method for production of low density polyester foam and articles made thereof utilizing low I.V. polyester feedstock > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,350 B2 - Document ID: US11111350B2 - Status: Granted - Kind: B2 - Application number: 16/167,508 - Filed: 2018-10-22 - Published: 2019-05-02 - Granted: 2021-09-07 - Earliest claimed: 2017-10-26 - Assignees: Wrh Technology, LLC - Applicants: Walter R. Harfmann - Inventors: Walter R. Harfmann - Web page: https://patentgrep.com/patent/US11111350B2 ## CPC - C08J 9/0061: {characterized by the use of several polymeric components} - B29B 11/10: Extrusion moulding - B29B 17/0005: {Direct recuperation and re-use of scrap material during moulding operation, i.e. feed-back of used material} - B29C 44/00: Shaping by internal pressure generated in the material, e.g. swelling or foaming {; Producing porous or cellular expanded plastics articles} - B29C 44/505: {extruding the compound through a flat die (in general B29C48/03)} - B29C 48/022: {characterised by the choice of material} - B29C 48/85: Cooling - B29C 51/002: {characterised by the choice of material} - B29C 51/02: Combined thermoforming and manufacture of the preform - C08J 3/203: {Solid polymers with solid and/or liquid additives} - C08J 3/24: Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) - C08J 9/36: After-treatment (C08J9/22 takes precedence) - 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 101/00: Compositions of unspecified macromolecular compounds - B29C 44/3446: {Feeding the blowing agent} - B29C 48/0017: {combined with blow-moulding or thermoforming} - B29C 48/0022: {combined with cutting} - B29C 48/025: General arrangement or layout of plant - B29C 48/07: Flat, e.g. panels - B29C 48/28: Storing of extruded material, e.g. by winding up or stacking - B29C 48/355: Conveyors for extruded articles - B29C 48/385: using two or more serially arranged screws in separate barrels - B29C 48/387: {using a screw extruder and a gear pump} - B29C 48/40: using two or more parallel screws {or at least two parallel non-intermeshing screws}, e.g. twin screw extruders - B29C 48/691: Arrangements for replacing filters, e.g. with two parallel filters for alternate use - B29C 48/90: with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article - B29C 2793/0027: Cutting off - B29C 2793/009: after shaping - B29K 2067/00: Use of polyesters {or derivatives thereof}, as moulding material - B29K 2105/04: cellular or porous - B29K 2105/26: Scrap {or recycled material} - B29K 2995/0063: Density - C08J 9/141: {Hydrocarbons} - C08J 2201/03: Extrusion of the foamable blend - C08J 2203/14: Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons - C08J 2203/182: of physical blowing agents, e.g. acetone and butane - C08J 2300/30: Polymeric waste or recycled polymer - C08J 2367/00: Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers - C08J 2400/30: Polymeric waste or recycled polymer - C08J 2467/00: Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers - 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) - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - 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) - 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 method for producing low density polyester foam utilizing low I.V. polyester feedstock includes providing a low intrinsic viscosity raw material. The low intrinsic viscosity raw material includes between 25% to 100% of a post consumer polyester and has an intrinsic viscosity of less than 0.8 dl/g. The intrinsic viscosity of the low intrinsic viscosity raw material is increased via a de-condensation reaction configured to support foaming. The intrinsic viscosity of the low intrinsic viscosity raw material is increased to 1.1 dl/g or greater. A starting formulation is created including the low intrinsic viscosity raw material with the increased intrinsic viscosity. The starting formulation is foamed to create the polyester foam. Wherein, the polyester foam produced has a specific gravity of less than 0.65 g/cc. ## Claims ### Claim 1 A method for producing a polyester foam comprising: providing a low intrinsic viscosity raw material, the low intrinsic viscosity raw material includes between 25% to 100% of a post consumer polyester, and the post consumer polyester has an intrinsic viscosity of less than 0.8 dl/g; increasing the intrinsic viscosity of the low intrinsic viscosity raw material via a de-condensation reaction configured to support foaming, wherein the intrinsic viscosity of the low intrinsic viscosity raw material is increased to 1.1 dl/g or greater; creating a starting formulation including the low intrinsic viscosity raw material with the increased intrinsic viscosity; foaming the starting formulation to create the polyester foam; wherein, the polyester foam produced has a specific gravity of less than 0.65 g/cc. ### Claim 2 (depends on 1) The method for producing the polyester foam of claim 1 further comprising: crystallizing the low intrinsic viscosity raw material in a crystallizer; or pelletizing the low intrinsic viscosity raw material; wherein the crystallizing or the pelletizing is configured to prevent the low intrinsic viscosity raw material from melting during the de-condensation reaction. ### Claim 3 (depends on 1) The method for producing the polyester foam of claim 1, wherein the low intrinsic viscosity raw material includes: virgin polyester; the post consumer polyester is a polyester feedstock that consists of a post-industrial waste resin; and process regrind; wherein the post-industrial waste resin of the low intrinsic viscosity raw material consists of post-consumer scrap bottle flake. ### Claim 4 (depends on 1) The method for producing the polyester foam of claim 1, wherein the increasing the viscosity of the low intrinsic viscosity raw material via the de-condensation reaction to support foaming including increasing a molecular weight of the low intrinsic viscosity raw material by feeding the low intrinsic viscosity raw material into a solid-state reactor, or by a melt-phase de-condensation reaction with vacuum using a melt phase reactor. ### Claim 5 (depends on 1) The method for producing the polyester foam of claim 1, wherein the creating of the starting formulation including adding: a viscosity enhancing agent configured to fine tune the viscosity of the low intrinsic viscosity raw material; a nucleating agent configured for aiding in nucleating the low intrinsic viscosity raw material; or combinations thereof. ### Claim 6 (depends on 5) The method for producing the polyester foam of claim 5, wherein: the viscosity enhancing agent is a cross-linking agent; the nucleating agent consists of a poly-flouro-ethylene particle; or combinations thereof. ### Claim 7 (depends on 1) The method for producing the polyester foam of claim 1, wherein the foaming of the starting formulation to create the polyester foam including tandem extrusion of the starting formulation to create the polyester foam, wherein the tandem extrusion of the starting formulation to create the polyester foam including: a primary twin screw extruder including an injection system and a blowing agent storage system configured to introduce a blowing agent into the starting formulation once the starting formulation is melted and mixed via the primary twin screw extruder, whereby a homogenous mixture exits the primary twin screw extruder; and a secondary cooling extruder configured to cool the homogenous mixture that exits the primary twin screw extruder for giving a necessary rheology needed to the homogenous solution for successful foaming, the secondary cooling extruder is configured to give heat exchange with minimal shear heat generation, the secondary cooling extruder includes a screw configured to act as a heat exchanger for removing heat from the homogenous mixture and increasing viscosity. ### Claim 8 (depends on 7) The method for producing the polyester foam of claim 7 further comprising: screening for solid impurities via a screen changer between the primary twin screw extruder and the secondary cooling extruder; and pressurizing the homogenous mixture exiting the primary twin screw extruder via a gear pump between the primary twin screw extruder and the secondary cooling extruder, said gear pump is configured impart minimal additional shear heat while pressurizing the homogenous mixture; wherein the blowing agent consists of a hydrocarbon selected from a group consisting of: C5 hydrocarbons; and C6 hydrocarbons. ### Claim 9 (depends on 7) The method for producing the polyester foam of claim 7 further comprising forming the polyester foam using a die, wherein the die is a board die or a sheet die configured with associated finishing equipment, wherein the associating finishing equipment including: a sizing drum; a pull unit; and a winder configured to create a roll of the polyester foam. ### Claim 10 (depends on 9) The method for producing the polyester foam of claim 9, wherein the pull unit is configured to pull a bubble of the polyester foam over the sizing drum and slit the bubble to open a flat sheet. ### Claim 11 (depends on 10) The method for producing the polyester foam of claim 10, wherein the polyester foam is produced as the flat sheet in a roll stock form to a thickness of at least 0.040 inches and of up to 0.375 inches thick. ### Claim 12 (depends on 10) The method for producing the polyester foam of claim 10, wherein the polyester foam is produced with a thicknesses greater than 0.5 inches and a width of greater than 6 inches. ### Claim 13 (depends on 10) The method for producing the polyester foam of claim 10, wherein: the flat sheet is used as a thermal barrier; the polyester foam is utilized as a wood or equivalent substitute; or combinations thereof. ### Claim 14 (depends on 11) The method for producing the polyester foam of claim 11, wherein the flat sheet is thermoformed into a useful article, wherein the useful article being selected from a group consisting of: a clamshell; a meat tray; a plates; and a bowl. ### Claim 15 (depends on 14) The method for producing the polyester foam of claim 14, wherein the flat sheet is thermoformed into the useful article via: unwinding the roll of flat sheet of the polyester foam; heating the unwinded roll of flat sheet in an oven, where temperatures of the oven are controlled to soften but not melt the flat sheet of the polyester foam; forming the heated flat sheet of the polyester foam in a forming station, where the heated flat sheet of the polyester foam is amorphous or crystallized when formed; cutting the formed flat sheet of the polyester foam in a trim press, where skeletal waste or regrind is stored to be reused; and packaging the useful article for sale. ### Claim 16 A method for producing a polyester foam comprising: providing a low intrinsic viscosity raw material, wherein the low intrinsic viscosity raw material includes between 25% to 100% of a post consumer polyester, wherein the low intrinsic viscosity raw material provided has an intrinsic viscosity of less than 0.8 dl/g, wherein the low intrinsic viscosity raw material includes: virgin polyester; the post consumer polyester is a polyester feedstock that consists of a post-industrial waste resin; and process regrind; wherein the post-industrial waste resin of the low intrinsic viscosity raw material consists of post-consumer scrap bottle flake; crystallizing the low intrinsic viscosity raw material in a crystallizer, wherein the crystallizing is configured to prevent the low intrinsic viscosity raw material from melting during a de-condensation reaction; increasing the intrinsic viscosity of the low intrinsic viscosity raw material via the de-condensation reaction configured to support foaming, wherein the intrinsic viscosity of the low intrinsic viscosity raw material is increased to 1.1 dl/g or greater including increasing a molecular weight of the low intrinsic viscosity raw material by feeding the low intrinsic viscosity raw material into a solid-state reactor; creating a starting formulation including the low intrinsic viscosity raw material with the increased intrinsic viscosity including adding: a cross-linking agent configured to fine tune the viscosity of the low intrinsic viscosity raw material; and a nucleating agent configured for aiding in nucleating the low intrinsic viscosity raw material, wherein the nucleating agent consists of a poly-flouro-ethylene particle; foaming the starting formulation to create the polyester foam including tandem extrusion of the starting formulation to create the polyester foam, wherein the tandem extrusion of the starting formulation to create the polyester foam including: a primary twin screw extruder including an injection system and a blowing agent storage system configured to introduce a blowing agent into the starting formulation once the starting formulation is melted and mixed via the primary twin screw extruder, whereby a homogenous mixture exits the primary twin screw extruder, wherein the blowing agent consists of a hydrocarbon selected from a group consisting of: C5 hydrocarbons; and C6 hydrocarbons; a secondary cooling extruder configured to cool the homogenous mixture that exits the primary twin screw extruder for giving a necessary rheology needed to the homogenous solution for successful foaming, the secondary cooling extruder is configured to give heat exchange with minimal shear heat generation, the secondary cooling extruder includes a screw configured to act as a heat exchanger for removing heat from the homogenous mixture and increasing viscosity; screening for solid impurities via a screen changer between the primary twin screw extruder and the secondary cooling extruder; and pressurizing the homogenous mixture exiting the primary twin screw extruder via a gear pump between the primary twin screw extruder and the secondary cooling extruder, said gear pump is configured to impart minimal additional shear heat while pressurizing the homogenous mixture; forming the polyester foam using a die, wherein the die is a board die or a sheet die configured with associated finishing equipment, wherein the associating finishing equipment including: a sizing drum; a pull unit; and a winder configured for creating a roll of the polyester foam; wherein the pull unit is configured to pull a bubble of the polyester foam over the sizing drum and slit the bubble to open a flat sheet, wherein the polyester foam is produced as the flat sheet in a roll stock form to a thickness of at least 0.040 inches and of up to 0.375 inches thick; wherein the polyester foam is produced with the thicknesses greater than 0.5 inches and widths of greater than 6 inches; wherein, the polyester foam produced has a specific gravity of less than 0.65 g/cc.