	US 12,240,928 B2
	Polyvinyl alcohol-based crosslinked copolymer
Yusuke Saegusa, Kurashiki (JP); Masahiro Baba, Kurashiki (JP); and Toshinori Kato, Kurashiki (JP)
Assigned to KURARAY CO., LTD., Kurashiki (JP)
Appl. No. 17/418,132
Filed by KURARAY CO., LTD., Kurashiki (JP)
PCT Filed Dec. 26, 2019, PCT No. PCT/JP2019/051283 § 371(c)(1), (2) Date Jun. 24, 2021, PCT Pub. No. WO2020/138356, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 2018-248012 (JP), filed on Dec. 28, 2018.
Prior Publication US 2022/0081502 A1, Mar. 17, 2022
Int. Cl. C08F 216/06 (2006.01); A01G 24/35 (2018.01); C08F 220/06 (2006.01); C08K 5/07 (2006.01); C08F 220/14 (2006.01)

CPC C08F 216/06 (2013.01) [A01G 24/35 (2018.02); C08F 220/06 (2013.01); C08K 5/07 (2013.01); C08F 220/14 (2013.01)]

9 Claims

1. A polyvinyl alcohol-based crosslinked copolymer, comprising:

an unsaturated monocarboxylic acid-based structural unit,

vinyl alcohol units, and

acetal crosslinking structures formed with a polyfunctional aldehyde having 2-20 carbon atoms,

wherein

an amount of carboxylate-forming structural units in the crosslinked copolymer is in a range of from 1.5 to 15 mol. %, based on total structural units in the crosslinked copolymer,

an amount of vinyl alcohol units in the polyvinyl alcohol-based crosslinked copolymer is in a range of from 20 to 98.5 mol. %, based on the total structural units in the crosslinked copolymer,

an amount of acetalized vinyl alcohol units of the crosslinked copolymer is from 0.01% to 50% by mole of the total of vinyl alcohol units,

and

a solubility of the crosslinked copolymer in water is 5% or more and 90% or less.