METHOD FOR PRODUCING OXYMETHYLENE COPOLYMER

摘要

Provided is a method for producing an oxymethylene copolymer continuously and with high polymerization yield, whereby it becomes possible to improve heat stability and the formaldehyde generation amount while keeping MD resistance and folding endurance. Provided is a method for producing an oxymethylene copolymer, which comprises the steps of: carrying out a copolymerization reaction of a monomer raw material comprising trioxane and 1,3-dioxolane in an amount of 7.0 to 22 mass % relative to the amount of trioxane in the presence of boron trifluoride in an amount of 0.03 to 0.10 mmol relative to 1 mol of trioxane and sterically hindered phenol in an amount of 0.006 to 2.0 mass % relative to the amount of trioxane; and adding a polymerization terminator to a reaction system at the point of time at which the polymerization yield of the copolymer becomes 92% or more to terminate the polymerization.

主权项

1. A process for producing an oxymethylene copolymer which comprises the steps of:
subjecting a monomer starting material comprising trioxane and 1,3-dioxolane in an amount of 7.0 to 22% by mass based on the mass of the trioxane, to a copolymerization reaction, in the presence of boron trifluoride in a proportion of 0.03 to 0.10 mmol per 1 mol of the trioxane and a sterically hindered phenol in an amount of 0.006 to 2.0% by mass based on the trioxane; and terminating the copolymerization reaction by adding a polymerization terminator into the reaction system at a point in time when the copolymerization reaction gives a polymerization yield of 92% or more.