Method for producing medium-molecular-weight polyalkyleneoxide

摘要

A method for producing a medium-molecular weight polyalkylene oxide having a viscosity-average molecular weight of from 100,000 to 2,500,000, including heat-treating a polyalkylene oxide having a viscosity-average molecular weight of 3,000,000 or more at a temperature of from 30° to 70° C. in an aliphatic hydrocarbon solvent having a dissolved oxygen concentration of 0.5 mg/L or more, in the presence of a radical initiator in an amount of from 0.001 to 1 part by mass, based on 100 parts by mass of the polyalkylene oxide, and thereafter adding an antioxidant to a mixture in an amount of from 0.001 to 5 parts by mass, based on 100 parts by mass of the polyalkylene oxide to remove the solvent. According to the method of the present invention, a medium-molecular weight polyalkylene oxide having a viscosity-average molecular weight of from 100,000 to 2,500,000 which has excellent storage stability can be industrially obtained without subjecting to a gamma-ray irradiation treatment.

主权项

1. A method for producing a medium-molecular weight polyalkylene oxide, the method comprising
heat-treating a polyalkylene oxide having a viscosity-average molecular weight of 3,000,000 or more at a temperature of from 30 to 50° C. in an aliphatic hydrocarbon solvent comprising dissolved oxygen at a concentration of 0.5 mg/L or more, in the presence of a radical initiator in an amount of from 0.001 to 1 part by mass, based on 100 parts by mass of the polyalkylene oxide, and thereafter adding an antioxidant in an amount of from 0.001 to 5 parts by mass, based on 100 parts by mass of the polyalkylene oxide to remove the solvent, thereby obtaining the medium-molecular weight polyalkylene oxide, which has a viscosity-average molecular weight of from 100,000 to 2,500,000, wherein the radical initiator has a 10-hour half-life temperature of 70° C. or lower and is at least one selected from the group consisting of an azonitrile, an azoamidine, an azoimidazoline, a sulfur-comprising compound, an oxidizing agent, and an organometallic compound.