| 摘要 |
PURPOSE: Provided is a method for preparing a polyamide resin, which can economically produce a polyamide resin having improved physical property, from caprolactam monomer or oligomer obtained when cleaning caprolactam polymer. CONSTITUTION: The method comprises the steps of (i) washing a caprolactam polymer with water to obtain an aqueous extract solution comprising caprolactam monomer and oligomer, (ii) concentrating the aqueous extract solution with adding 3,4,5,6-dibenzo-1,2-oxyphosphine-2-oxide as a stabilizer to the solution, so as to form a concentrate, and (iii) polymerizing the concentrate. The amount of added 3,4,5,6-dibenzo-1,2-oxyphosphine-2-oxide is 10-5,000 ppm.
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