	US 12,116,454 B2
	Method for producing polyalkylene oxide and polyalkylene oxide
Akira Kimura, Himeji (JP); and Yuika Imamura, Himeji (JP)
Assigned to SUMITOMO SEIKA CHEMICALS CO., LTD., Hyogo (JP)
Filed by SUMITOMO SEIKA CHEMICALS CO., LTD., Hyogo (JP)
Filed on Sep. 14, 2022, as Appl. No. 17/944,339.
Claims priority of application No. 2021-150544 (JP), filed on Sep. 15, 2021.
Prior Publication US 2023/0088981 A1, Mar. 23, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C08G 65/12 (2006.01); C08G 65/26 (2006.01); C08G 65/30 (2006.01); C08J 3/28 (2006.01); C08K 5/13 (2006.01)

CPC C08G 65/12 (2013.01) [C08G 65/2609 (2013.01); C08G 65/30 (2013.01); C08J 3/28 (2013.01); C08K 5/13 (2013.01); C08G 2650/58 (2013.01); C08J 2371/02 (2013.01)]

14 Claims

1. A method for producing a polyalkylene oxide, comprising

a step of irradiating a high-molecular-weight polyalkylene oxide with radiation in the presence or absence of an antioxidant to obtain a polyalkylene oxide,

wherein

the high-molecular-weight polyalkylene oxide before irradiation has a viscosity at 25° C. in a 1 mass % aqueous solution of 1500 to 16000 mPa·s, the mass % aqueous solution being the mass percentage of the high-molecular-weight polyalkylene oxide based on the total mass of the high-molecular-weight polyalkylene oxide and water,

when the antioxidant is present, the antioxidant is present in an amount of less than 2000 mass ppm relative to the total mass of the high-molecular-weight polyalkylene oxide, and

the following formula (1):

0≤C³×I×10⁻⁸<30 (1),

wherein

C is the concentration of the antioxidant used in the above step, and represents the proportion (mass ppm) of the antioxidant relative to the total mass of the polyalkylene oxide, and I represents the irradiation dose (kGy) of the radiation emitted in the above step,

is satisfied.