	US 12,264,215 B2
	Vinyl alcohol-based block copolymer and method for producing same
Takumi Takayama, Kurashiki (JP); Kazutoshi Mishima, Kurashiki (JP); Hiroyuki Konishi, Kurashiki (JP); and Kazuhiko Maekawa, Kurashiki (JP)
Assigned to KURARAY CO., LTD., Kurashiki (JP)
Appl. No. 17/623,105
Filed by KURARAY CO., LTD., Kurashiki (JP)
PCT Filed Jun. 25, 2020, PCT No. PCT/JP2020/024961 § 371(c)(1), (2) Date Dec. 27, 2021, PCT Pub. No. WO2020/262517, PCT Pub. Date Dec. 30, 2020.
Claims priority of application No. 2019-122215 (JP), filed on Jun. 28, 2019.
Prior Publication US 2022/0267499 A1, Aug. 25, 2022
Int. Cl. C08F 293/00 (2006.01); C08F 4/40 (2006.01); C08F 4/70 (2006.01); C08F 8/12 (2006.01); C08F 220/14 (2006.01); C08F 297/02 (2006.01); C08F 297/06 (2006.01); C08L 53/00 (2006.01)

CPC C08F 293/00 (2013.01) [C08F 4/40 (2013.01); C08F 4/7095 (2013.01); C08F 8/12 (2013.01); C08F 220/14 (2013.01); C08F 297/026 (2013.01); C08F 297/06 (2013.01); C08L 53/005 (2013.01)]

20 Claims

1. A vinyl alcohol-based block copolymer that is a block copolymer comprising a vinyl alcohol-based polymer block and a copolymer block, the copolymer block comprising a vinyl alcohol-based monomer unit and an acrylic acid-based monomer unit, wherein:

a content of the acrylic acid-based monomer unit relative to all monomer units is 0.05 to 20.0 mol %,

the block copolymer has a saponification degree of 80 to 99.99 mol %,

the block copolymer has a number-average molecular weight (Mn_a) of 20,000 to 440,000,

the block copolymer has a molecular weight distribution (Mw_a/Mn_a) of 1.05 to 1.95, and

a ratio of the number-average polymerization degree of the vinyl alcohol-based polymer block to the number-average polymerization degree of the block copolymer is 0.010 to 0.999.