Patent ID: 11091574

Abstract:
The present invention provides an industrially advantageous method for producing vinyl alcohol polymers having a low degree of polymerization using a chain transfer agent having an aliphatic hydrocarbon group having 6 to 12 carbon atoms, the method being capable of producing a vinyl alcohol polymer whose aqueous solution has excellent viscosity stability. The present invention relates to a method for producing vinyl alcohol polymers, including: polymerizing a vinyl ester monomer (a) in the presence of a polymerization initiator (B) and a chain transfer agent (C) having an aliphatic hydrocarbon group having 6 to 12 carbon atoms to obtain a vinyl ester polymer (A); and saponifying the vinyl ester polymer (A) at a concentration of 40 mass % or more and 75 mass % or less in the presence of an acidic catalyst (D) to obtain a vinyl alcohol polymer, wherein the vinyl alcohol polymer has a viscosity-average degree of polymerization of 160 or more and 400 or less.