| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of producing a high quality polyamide including reduced amount of caprolactam content and polyamide oligomer content advantageously in an industrial scale with low cost, in a method of production of polyamide using recovered lactam as raw material or a part of the raw material. SOLUTION: This invention includes the method for producing polyamide using recovered lactam obtained by a melt volatilization as raw material or a part of the raw material, the method for producing polyamide which uses the recovered lactam obtained by the melt volatilization as raw material or a part of the raw material, by treating at 200-330 deg.C for 1-30 min in a pressurized condition to produce a polyamide prepolymer and then polymerizing the polyamide prepolymer, or the method for producing polyamide using the lactam recovered by the melt colatilization preferably from a vented twin-screw extruder, as raw material or a part of the raw material by treating at 200-330 deg.C for 1-30 min in a pressurized condition to produce a polyamide prepolymer and then polymerizing the polyamide prepolymer in a normal pressure.
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