Abstract: A Polyvinylidene fluoride-based microporous membrane comprising: a substrate film; and the following microporous membrane, wherein the microporous membrane is an asymmetric membrane, and has a skin layer in which micropores are formed and a support layer which supports the skin layer and in which pores larger than the micropores are formed, a material of the microporous membrane is a polyvinylidene fluoride-based resin, the skin layer has a plurality of spherical bodies, a plurality of linear binding materials extend three-dimensionally from the respective spherical bodies, the adjacent spherical bodies are connected with each other by the linear binding materials to form a three-dimensional network structure where the spherical bodies serve as intersections, and the number of defects (the number of colored coarse voids) is less than 20.

Abstract: Provided is a microporous membrane which has an asymmetric structure and which exhibits higher permeability while keeping a high particle rejection. This microporous membrane is an asymmetric microporous membrane that is provided with: a skin layer in which micropores have been formed; and a support layer which supports the skin layer and in which pores larger than the micropores have been formed. The material of the microporous membrane is a polyvinylidene fluoride-based resin. In the skin layer, multiple spherical bodies (1) are present, and multiple linear joining parts (2) extend three-dimensionally from each of the spherical bodies (1), each pair of adjacent spherical bodies (1) being linked to each other by one or more of the linear joining parts (2). Thus, the skin layer has a three-dimensional network structure wherein the spherical bodies (1) act as nodes.

Abstract: Provided is a microporous membrane which has an asymmetric structure and which exhibits higher permeability while keeping a high particle rejection. This microporous membrane is an asymmetric microporous membrane that is provided with: a skin layer in which micropores have been formed; and a support layer which supports the skin layer and in which pores larger than the micropores have been formed. The material of the microporous membrane is a polyvinylidene fluoride-based resin. In the skin layer, multiple spherical bodies (1) are present, and multiple linear joining parts (2) extend three-dimensionally from each of the spherical bodies (1), each pair of adjacent spherical bodies (1) being linked to each other by one or more of the linear joining parts (2). Thus, the skin layer has a three-dimensional network structure wherein the spherical bodies (1) act as nodes.