Method for producing polymer, and polymer
View Patent ↗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.
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.
2. The method according to claim 1 , wherein the polymer is a polyester-based polymer.
3. 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.
4. 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.
5. 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.
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.
7. 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.
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.
9. 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.
10. The method according to claim 8 , wherein the polymer is a polyester-based polymer.
11. 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.