US 12,447,445 B2
Porous separation membrane
Kaori Akaike, Tokyo (JP); Akihiro Hayashi, Otsu (JP); and Hirokazu Sakaguchi, Otsu (JP)
Assigned to TORAY INDUSTRIES, INC., Tokyo (JP)
Appl. No. 17/777,725
Filed by TORAY INDUSTRIES, INC., Tokyo (JP)
PCT Filed Nov. 19, 2020, PCT No. PCT/JP2020/043182
§ 371(c)(1), (2) Date May 18, 2022,
PCT Pub. No. WO2021/100804, PCT Pub. Date May 27, 2021.
Claims priority of application No. 2019-210190 (JP), filed on Nov. 21, 2019.
Prior Publication US 2023/0024252 A1, Jan. 26, 2023
Int. Cl. B01D 71/68 (2006.01); B01D 67/00 (2006.01); B01D 69/02 (2006.01); B01D 69/08 (2006.01); B01D 71/38 (2006.01); B01D 71/44 (2006.01); B01D 71/82 (2006.01)
CPC B01D 71/68 (2013.01) [B01D 67/0088 (2013.01); B01D 69/02 (2013.01); B01D 69/08 (2013.01); B01D 71/381 (2022.08); B01D 71/441 (2022.08); B01D 71/82 (2013.01); B01D 2323/02 (2013.01); B01D 2323/04 (2013.01); B01D 2323/18 (2013.01); B01D 2325/022 (2013.01); B01D 2325/34 (2013.01); B01D 2325/58 (2022.08)] 9 Claims
OG exemplary drawing
 
1. A porous separation membrane that has an asymmetric structure with a dense layer located near a first surface and a coarse layer located near a second opposite surface, and that supports a biocompatible polymer, wherein a proportion of carbon atoms (atom count percentage) derived from an ester group by measurement by an X-ray photoelectron spectrometer (XPS) is larger near the second opposite surface than the first surface, and the porous separation membrane meets requirements (1) and (2) given below in a surface analysis of a cross section containing the dense layer and the coarse layer performed by TOF-SIMS:
(1) a minimum value of normalized intensity of the ion signal attributed to the biocompatible polymer in the coarse layer is 0.15 times or more of a maximum value thereof and
(2) a normalized average intensity of the ion signal attributed to the biocompatible polymer in the dense layer is 2.0 times or more of a normalized average intensity of the ion signal attributed to the biocompatible polymer in the coarse layer;
wherein the biocompatible polymer is a polymer containing a monocarboxylic acid vinyl ester unit;
wherein the polymer containing a monocarboxylic acid vinyl ester is a copolymer including a hydrophobic unit and a hydrophilic unit;
wherein the hydrophobic unit comprises a monocarboxylic acid vinyl ester unit; and
wherein the hydrophilic unit is a vinylpyrrolidone unit.