US 11,794,150 B2
Separation membrane and method for producing separation membrane
Hiroki Eimura, Otsu (JP); Koichi Takada, Otsu (JP); Marina Otsuka, Otsu (JP); and Masayuki Hanakawa, Otsu (JP)
Assigned to TORAY INDUSTRIES, INC., Tokyo (JP)
Appl. No. 17/786,707
Filed by Toray Industries, Inc., Tokyo (JP)
PCT Filed Dec. 23, 2020, PCT No. PCT/JP2020/048299
§ 371(c)(1), (2) Date Jun. 17, 2022,
PCT Pub. No. WO2021/132399, PCT Pub. Date Jul. 1, 2021.
Claims priority of application No. 2019-231580 (JP), filed on Dec. 23, 2019.
Prior Publication US 2023/0053706 A1, Feb. 23, 2023
Int. Cl. B01D 69/02 (2006.01); B01D 65/08 (2006.01); B01D 67/00 (2006.01); B01D 69/08 (2006.01); B01D 71/22 (2006.01); B01D 71/34 (2006.01); B01D 71/40 (2006.01); B01D 71/44 (2006.01); B01D 71/48 (2006.01); B01D 71/52 (2006.01); B01D 71/56 (2006.01); B01D 71/66 (2006.01)
CPC B01D 69/02 (2013.01) [B01D 65/08 (2013.01); B01D 67/0009 (2013.01); B01D 67/0083 (2013.01); B01D 69/08 (2013.01); B01D 71/22 (2013.01); B01D 71/34 (2013.01); B01D 71/40 (2013.01); B01D 71/44 (2013.01); B01D 71/48 (2013.01); B01D 71/52 (2013.01); B01D 71/56 (2013.01); B01D 71/66 (2013.01); B01D 2323/12 (2013.01); B01D 2325/022 (2013.01); B01D 2325/0283 (2022.08); B01D 2325/04 (2013.01); B01D 2325/20 (2013.01); B01D 2325/24 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A separation membrane comprising, as a main component A, a thermoplastic polymer selected from the group consisting of a cellulose ester and a polyamide,
wherein, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval in order from one surface of the separation membrane in a thickness direction of the separation membrane are defined as regions 1 to 5,
an average pore diameter obtained by weighting with a pore area ratio of pores extracted in each region to a total area of all the pores is defined as an area average pore diameter Ds in each region,
an average pore diameter obtained by weighting with a number ratio of pores extracted in each region to the number of all pores is defined as a number average pore diameter Dn in each region,
a pore having a pore diameter larger than the area average pore diameter Ds is defined as a coarse pore,
a pore having a pore diameter smaller than the number average pore diameter Dn is defined as a fine pore,
an average of closest distance between coarse pores is defined as La, and
a number average W of the fine pores that are located at a distance smaller than La from a center of the respective coarse pores is calculated,
all the regions 1 to 5 have a number average pore diameter changing rate αi defined by the following Formula of −0.25 or more and 0.25 or less, and
at least one of the regions 1 to 5 is a region P that satisfies the following conditions (a) and (b):
(a) a value of the area average pore diameter Ds/the number average pore diameter Dn is 2.50 or more and 6.00 or less; and
(b) the number average W of the fine pores is 10 or more and 30 or less,
αi=(Di−Di+1)/Di
(Di: Number average pore diameter of region i),
it is noted that the number average pore diameter changing rate in the region 5 is defined by the following formula,
α5=(D5−D4)/D5.