# US 10,307,752 B2 · Method for producing polymer, and polymer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,307,752 B2 - Document ID: US10307752B2 - Status: Granted - Kind: B2 - Application number: 14/409,827 - Filed: 2013-06-25 - Published: 2015-07-09 - Granted: 2019-06-04 - Earliest claimed: 2012-06-26 - Assignees: Mitsubishi Chemical Corporation - Applicants: Mitsubishi Chemical Corporation - Inventors: Seiji Tsuchiya; Shinichi Maeda - Web page: https://patentgrep.com/patent/US10307752B2 ## CPC - B01J 41/12: Macromolecular compounds - B01J 39/18: Macromolecular compounds (B01J39/17 takes precedence) - C08G 63/6856: {Dicarboxylic acids and dihydroxy compounds} - C08G 63/916: {Dicarboxylic acids and dihydroxy compounds} - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract A method for producing a polymer of the present invention includes the following steps (a) and (b): step (a): producing a polymer in the presence of an acid or base catalyst; and step (b): contacting a solution containing the polymer obtained in step (a) to a mixed resin of an anion-exchange resin and a cation-exchange resin. ## Claims ### Claim 1 A method for producing a polymer, the method comprising: producing a polymer by polymerizing monomers in the presence of an acid catalyst, terminating the polymerization using a basic compound and attaching a crosslinking agent to a side chain of the polymer; subsequently contacting a solution comprising the polymer with a mixed resin of an anion-exchange resin and a cation-exchange resin, to reduce residual metal impurities, acidic impurities, and basic impurities to a level such that a sum of concentrations of acidic and basic impurities is 50 ppm or lower; and metal impurity concentrations of sodium, potassium, calcium and iron are each 80 ppb or lower, subsequently passing the solution comprising the polymer through a filter that does not comprise a strongly acidic ion-exchange group but comprises a charge control agent for generating zeta potential, wherein the acid catalyst is p-tolulenesulfonic acid, and a mass ratio of the anion exchange resin to the cation-exchange resin is from 60/40 to 99/1. ### Claim 2 (depends on 1) The method according to claim 1, wherein the polymer is a polyester-based polymer. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: subsequently producing a powdery polymer by mixing the solution comprising the polymer and a poor solvent for the polymer so that the polymer is deposited. ### Claim 4 (depends on 1) The method according to claim 1, wherein the filter is a filter sheet, and an average pore diameter of the filter sheet is 0.5 to 10 μm. ### Claim 5 (depends on 4) The method according to claim 4, further comprising: subsequently producing a powdery polymer by mixing the solution comprising the polymer and a poor solvent for the polymer so that the polymer is deposited. ### Claim 6 A method for producing a polymer, comprising: producing a polymer by polymerizing monomers in the presence of a base catalyst, terminating the polymerization using an acidic compound, and attaching a crosslinking agent to a side chain of the polymer; subsequently contacting a solution comprising the polymer with a mixed resin of an anion-exchange resin and a cation-exchange resin, to reduce residual metal impurities, acidic impurities, and basic impurities to a level such that a sum of concentrations of acidic and basic impurities is 50 ppm or lower; and metal impurity concentrations of sodium, potassium, calcium and iron are each 80 ppb or lower, and subsequently passing the solution comprising the polymer through a filter that does not comprise a strongly acidic ion-exchange group but comprises a charge control agent for generating zeta potential, wherein the base catalyst is a tertiary amine. ### Claim 7 (depends on 1) The method according to claim 1, wherein prior to passing the solution comprising the polymer through the filter that does not comprise a strongly acidic ion-exchange group but comprises a charge control agent for generating zeta potential the filter is cleaned using ultrapure water and a solvent of the solution. ### Claim 8 A method for producing a polymer, the method comprising: producing a polymer by polymerizing monomers in the presence of a base catalyst, terminating the polymerization using an acidic compound, and attaching a crosslinking agent to a side chain of the polymer; and subsequently contacting a solution comprising the polymer with a mixed resin of an anion-exchange resin and a cation-exchange resin, to reduce residual metal impurities, acidic impurities, and basic impurities to a level such that a sum of concentrations of acidic and basic impurities is 50 ppm or lower; and metal impurity concentrations of sodium, potassium, calcium and iron are each 80 ppb or lower, wherein the base catalyst is a tertiary amine. ### Claim 9 (depends on 8) The method according to claim 8, wherein a mass ratio of the anion-exchange resin to the cation-exchange resin is from 60/40 to 99/1. ### Claim 10 (depends on 8) The method according to claim 8, wherein the polymer is a polyester-based polymer. ### Claim 11 (depends on 8) The method according to claim 8, further comprising: subsequently producing a powdery polymer by mixing the solution comprising the polymer and a poor solvent for the polymer so that the polymer is deposited.