# US 12,215,176 B2 · Method for preparing polymer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,215,176 B2 - Document ID: US12215176B2 - Status: Granted - Kind: B2 - Application number: 17/627,568 - Filed: 2021-07-01 - Published: 2023-10-19 - Granted: 2025-02-04 - Earliest claimed: 2020-07-17 - Assignees: LG Chem, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Jeong A Hwang; Dae Young Shin; Eun Jung Joo - Web page: https://patentgrep.com/patent/US12215176B2 ## CPC - C08F 212/10: with nitriles - B01D 53/002: {by condensation} - C08F 2/01: characterised by special features of the polymerisation apparatus used - C08F 2/06: Organic solvent - C08F 6/00: Post-polymerisation treatments (C08F8/00 takes precedence; of conjugated diene rubbers C08C) - C08F 6/003: {from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom} - C08F 6/12: Separation of polymers from solutions - B01D 2257/708: Volatile organic compounds V.O.C.'s - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract Provided is a method of preparing a polymer including: supplying a monomer stream and a solvent stream to a reactor and performing a polymerization reaction to prepare a reaction product; supplying a reactor discharge stream to a volatilization device, separating a polymer from a lower portion of the volatilization device, splitting an upper discharge stream including an unreacted monomer, a solvent, and an inert gas into two or more streams, and divisionally supplying the split streams to a plurality of condensers, respectively; condensing and separating the unreacted monomer and the solvent in each of the condensers and supplying a gaseous stream therefrom to a condenser installed at a rear end of each condenser; and supplying a gaseous stream discharged from a condenser installed at the rearmost end to a vacuum unit. ## Claims ### Claim 1 A method of preparing a polymer, the method comprising: supplying a monomer stream and a solvent stream to a reactor and performing a polymerization reaction to prepare a reaction product; supplying a reactor discharge stream to a volatilization device comprising the reaction product, separating a polymer from a lower portion of the volatilization device, and splitting an upper discharge stream including an unreacted monomer, a solvent, and an inert gas into two or more streams comprising a first stream and a second stream; supplying the first stream to a first condenser and the second stream to a second condenser; at the first condenser, condensing and separating unreacted monomer and solvent and supplying a third gaseous stream to the second condenser; and supplying a gaseous stream discharged from the second condenser to a vacuum unit. ### Claim 2 (depends on 1) The method of preparing a polymer of claim 1, wherein the first condenser is supplied with the first upper discharge stream from the volatilization device and condenses and separates the unreacted monomer and the solvent, and a remaining gaseous stream is supplied to the second condenser as the third gaseous stream, and the second condenser is provided with the second stream of the upper discharge stream from the volatilization device and the third gaseous stream discharged from the first condenser and condenses and separates the unreacted monomer and the solvent, and a remaining gaseous stream is supplied to the vacuum unit as the gaseous stream discharged from the second condenser. ### Claim 3 (depends on 2) The method of preparing a polymer of claim 2, wherein a flow rate ratio of the second stream is 0.1% to 50% with respect to a total flow rate of the upper discharge stream from the volatilization device. ### Claim 4 (depends on 3) The method of preparing a polymer of claim 3, wherein the flow rate ratio of the second stream is 1% to 30% with respect to the total flow rate of the upper discharge stream from the volatilization device. ### Claim 5 (depends on 1) The method of preparing a polymer of claim 1, wherein the upper discharge stream from the volatilization device includes 10 wt % to 95 wt % of the unreacted monomer, 5 wt % to 60 wt % of the solvent, and 100 ppm to 800 ppm of the inert gas. ### Claim 6 (depends on 2) The method of preparing a polymer of claim 2, wherein a content of the inert gas in the third gaseous stream discharged from the first condenser is 1,000 ppm to 20,000 ppm. ### Claim 7 (depends on 2) The method of preparing a polymer of claim 2, wherein the second stream of the upper discharge stream from the volatilization device and the third gaseous stream discharged from the first condenser form a mixed stream and the mixed stream is supplied to the second condenser. ### Claim 8 (depends on 7) The method of preparing a polymer of claim 7, wherein a content of the inert gas in the mixed stream is 500 ppm to 15,000 ppm. ### Claim 9 (depends on 8) The method of preparing a polymer of claim 8, wherein the content of the inert gas in the mixed stream is lower than the content of the inert gas in the third gaseous stream discharged from the first condenser by 100 ppm or more. ### Claim 10 (depends on 2) The method of preparing a polymer of claim 2, wherein a refrigerant supplied to the first condenser has a temperature of 20° C. to 40° C. and a flow rate of 50 ton/hr to 200 ton/hr. ### Claim 11 (depends on 2) The method of preparing a polymer of claim 2, wherein a refrigerant supplied to the second condenser has a temperature of 5° C. to 15° C. and a flow rate of 10 ton/hr to 100 ton/hr. ### Claim 12 (depends on 1) The method of preparing a polymer of claim 1, wherein the polymer includes an aromatic vinyl-unsaturated nitrile-based copolymer.