US 11,667,745 B2
Method for producing oxymethylene copolymer
Toru Takahashi, Tokyo (JP); Daigo Nakaya, Tokyo (JP); Kensuke Oshima, Tokyo (JP); and Daisuke Sunaga, Yokkaichi (JP)
Assigned to MITSUBISHI GAS CHEMICAL COMPANY, INC., Tokyo (JP)
Appl. No. 16/347,072
Filed by MITSUBISHI GAS CHEMICAL COMPANY, INC., Tokyo (JP)
PCT Filed Nov. 6, 2017, PCT No. PCT/JP2017/039926
§ 371(c)(1), (2) Date May 2, 2019,
PCT Pub. No. WO2018/084281, PCT Pub. Date May 11, 2018.
Claims priority of application No. JP2016-216918 (JP), filed on Nov. 7, 2016.
Prior Publication US 2020/0055974 A1, Feb. 20, 2020
Int. Cl. C08G 2/24 (2006.01)
CPC C08G 2/24 (2013.01) 16 Claims
 
1. A method for producing an oxymethylene copolymer, the method comprising subjecting a copolymer starting material comprising trioxane and a comonomer to polymerization reaction in the presence of a polymerization initiator comprising an acidic compound (A), wherein
the copolymer starting material comprises a basic compound (B);
an acidic compound (C) different from the acidic compound (A) is added to the copolymer starting material prior to the polymerization reaction to allow reaction between the basic compound (B) and the acidic compound (C) in advance, wherein the acidic compound (C) is sulfurous acid; and
the polymerization reaction is carried out through melt polymerization.