# US 10,479,003 B2 · Solid state microcellular foaming method including continuous saturation of solid polymeric material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,003 B2 - Document ID: US10479003B2 - Status: Granted - Kind: B2 - Application number: 15/248,091 - Filed: 2016-08-26 - Published: 2017-03-02 - Granted: 2019-11-19 - Earliest claimed: 2015-08-31 - Assignees: Dart Container Corporation - Applicants: Dart Container Corporation - Inventors: Michael Waggoner - Web page: https://patentgrep.com/patent/US10479003B2 ## CPC - B29C 44/3453: {Feeding the blowing agent to solid plastic material} - B29B 13/00: Conditioning or physical treatment of the material to be shaped (chemical aspects C08J3/00 {; heating, cooling or curing during shaping B29C35/00; thermal after-treatment B29C71/02}) - C08J 9/122: {Hydrogen, oxygen, CO2, nitrogen or noble gases} - B29C 44/358: {Foamed of foamable fibres} - B29L 2007/00: Flat articles, e.g. films or sheets (B29L2024/00 takes precedence) - B29L 2007/007: {Narrow strips, e.g. ribbons, tapes, bands (belts B29L2029/00; tapes as carrier of sound or information B29L2017/008)} - C08J 2203/06: CO2, N2 or noble gases - C08J 2300/22: Thermoplastic resins - 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) - 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 - 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) - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract A method for saturating a thermoplastic polymer material includes continuously moving the polymer material through a pressurized pressure vessel. To do this, the method includes sealing the pressure vessel with a series of dynamic seals that allows the polymer material to continuously move through the pressure vessel while maintaining the pressure inside the pressure vessel. ## Claims ### Claim 1 A solid state microcellular foaming method that includes saturating a solid polymeric material with a pressurized inert gas in a pressure vessel, the method comprising: continuously passing the solid polymeric material through a first set of cascading seals fluidly sealing an inlet to the pressure vessel; exposing the solid polymeric material passing through an interior of the pressure vessel to the pressurized inert gas to form a saturated solid polymeric material, wherein the inert gas in the saturated solid polymeric material forms microcellular bubbles in the saturated solid polymeric material in a subsequent foaming stage; continuously passing the saturated solid polymeric material through a second set of cascading seals fluidly sealing an outlet to the pressure vessel; and operating a pressure regulation system to control the pressure across each of the first set of cascading seals, the second set of cascading seals, and the interior of the pressure vessel. ### Claim 2 (depends on 1) The method of claim 1 wherein the solid polymeric material comprises at least one of a sheet, rod, or fiber. ### Claim 3 (depends on 2) The method of claim 2 wherein the solid polymeric material comprises a sheet. ### Claim 4 (depends on 1) The method of claim 1 wherein passing the solid polymeric material through the first set of cascading seals comprises sequentially increasing the pressure at each of the seals in the first set of cascading seals. ### Claim 5 (depends on 4) The method of claim 4 wherein passing the solid polymeric material through the second set of cascading seals comprises sequentially decreasing the pressure at each of the seals in the second set of cascading seals. ### Claim 6 (depends on 1) The method of claim 1 wherein a pressure differential across each seal in at least one of the first or second set of cascading seals is equal. ### Claim 7 (depends on 1) The method of claim 1 wherein a pressure differential across each seal in at least one of the first or second set of cascading seals is not equal. ### Claim 8 (depends on 1) The method of claim 1 wherein the pressurized inert gas is carbon dioxide. ### Claim 9 (depends on 1) The method of claim 1 wherein the pressurized inert gas is 500 psig. ### Claim 10 (depends on 1) The method of claim 1 wherein the solid polymeric material is at least one of fed from a roll as it passes into the inlet or is taken up on a roll after it passes from the outlet. ### Claim 11 (depends on 1) The method of claim 1 further comprising, prior to passing the solid polymeric material through the first set of cascading seals, extruding a plastic polymeric material to form the solid polymeric material. ### Claim 12 (depends on 1) The method of claim 1 further comprising, subsequent to passing the saturated solid polymeric material through the outlet of the pressure vessel, passing the saturated solid polymeric material to a foaming stage to induce microcellular bubble nucleation and growth. ### Claim 13 (depends on 12) The method of claim 12 wherein the foaming stage includes heating the saturated solid polymeric material. ### Claim 14 (depends on 1) The method of claim 1 wherein the interior of the pressure vessel is free of seals. ### Claim 15 (depends on 1) The method of claim 1 wherein the pressure regulation system comprises an external gas source that adds high pressure gas to the pressure vessel. ### Claim 16 (depends on 1) The method of claim 1 wherein the pressure regulation system comprises an active pump system that both pressurizes and depressurizes one or more sections of the pressure vessel. ### Claim 17 (depends on 16) The method of claim 16 wherein the one or more sections of the pressure vessel includes one or more of the first set of cascading seals, the second set of cascading seals, and the interior of the pressure vessel. ### Claim 18 A solid state microcellular foaming method that includes saturating a sheet of solid thermoplastic polymeric material with a pressurized inert gas in a pressure vessel, the method comprising: continuously passing the sheet of solid thermoplastic polymeric material through a first set of cascading seals fluidly sealing an inlet to the pressure vessel; exposing the sheet of solid thermoplastic polymeric material passing through an interior of the pressure vessel to the pressurized inert gas to form a saturated sheet of solid thermoplastic polymeric material, wherein the inert gas in the saturated sheet of solid thermoplastic polymeric material forms microcellular bubbles in the saturated sheet of solid thermoplastic polymeric material in a subsequent foaming stage; continuously passing the saturated sheet of solid thermoplastic polymeric material through a second set of cascading seals fluidly sealing an outlet to the pressure vessel; and operating a pressure regulation system to control the pressure across each of the first set of cascading seals, the second set of cascading seals, and the interior of the pressure vessel. ### Claim 19 A solid state microcellular foaming method that includes saturating a solid polymeric material with a pressurized inert gas in a pressure vessel, the method comprising: continuously passing the solid polymeric material through a first set of cascading seals fluidly sealing an inlet to the pressure vessel; exposing the solid polymeric material passing through an interior of the pressure vessel to the pressurized inert gas to allow continuous saturation and to form a saturated solid polymeric material, wherein the inert gas in the saturated solid polymeric material forms microcellular bubbles in the saturated solid polymeric material in a subsequent foaming stage; continuously passing the saturated solid polymeric material through a second set of cascading seals fluidly sealing an outlet to the pressure vessel; and operating a pressure regulation system to control the pressure across each of the first set of cascading seals, the second set of cascading seals, and the interior of the pressure vessel. ### Claim 20 (depends on 19) The method of claim 19 wherein the continuously passing the solid polymeric material through the first set of cascading seals and the second set of cascading seals reduces an amount of the pressurized inert gas that escapes from the pressure vessel.