Method for preparing polyamide resin
The present invention relates to a method for preparing a polyamide resin, comprising the steps of: (a) preparing a polyamide polymer by anionically polymerizing a monomer including 2-pyrrolidone; (b) refining an unreacted monomer and a catalyst in the polyamide polymer with water; (c) pH-controlling through an ion exchange of the refined water; and (d) recovering the unreacted monomer by concentrating the pH-controlled water.
1. A method for preparing a polyamide resin, comprising:
(a) preparing a polyamide polymer by anionically polymerizing a monomer including 2-pyrrolidone;
(b) refining an unreacted monomer and a catalyst in the polyamide polymer with water;
(c) pH-controlling through an ion exchange of the refined water; and
(d) recovering the unreacted monomer by concentrating the pH-controlled water.
2. The method of claim 1 , wherein the monomer including 2-pyrrolidone in step (a) is obtained from a biomass.
3. The method of claim 1 , wherein the monomer including 2-pyrrolidone in step (a) is a single form of 2-pyrrolidone monomer; or a mixed form of the 2-pyrrolidone monomer and a C5-C7 lactam monomer.
4. The method of claim 1 , wherein in step (a), an alkaline catalyst s added at the time of the anionically polymerizing.
5. The method of claim 1 , wherein in step (a), a CO 2 initiator and an isocyanate-based compound are added at the time of the anionically polymerizing.
6. The method of claim 1 , wherein in step (b), the refining is performed in a counter current manner.
7. The method of claim 1 , wherein in step (d), the concentrating is performed in a membrane filtration manner.
8. The method of claim 7 , wherein it is further performed in a distillation manner.
9. The method of claim 7 , wherein the membrane filtration manner is performed by reverse osmotic membrane, nano filtration membrane, pervaporation, or membrane distillation.
10. The method of claim 1 , wherein the polyamide resin is a resin polymerized from 2-pyrrolidone monomer; or a resin polymerized from 2-pyrrolidone monomer and a C5-C7 lactam monomer.