| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently and economically producing polyacetal reduced in formaldehyde content, scarcely causing yellowing and contamination of molds. SOLUTION: The method for producing the polyacetal resin composition reduced in formaldehyde comprises melting a polyoxymethylene copolymer immediately after polymerization in which a catalyst is deactivated in an extruder (A), continuously introducing the melted copolymer into a twin-shaft surface renewal type horizontal kneader in the melted state, devolatilizing the melted copolymer under reduced pressure of 1.01×10<SP>2</SP>to 1.33×10<SP>-2</SP>kPa at 190-240°C internal resin temperature and further kneading a polyacetal copolymer discharged from the twin-shaft surface renewal type horizontal kneader with a formaldehyde scavenger and devolatilizing the kneaded material under reduced pressure in an extruder (B) in which a kneading part having a length not longer than 3D<SB>2</SB>[D<SB>2</SB>is an inner diameter of the extruder (B)] is installed. COPYRIGHT: (C)2007,JPO&INPIT
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