Polyolefin microporous membrane, filter, chromatography carrier, and immunochromatographic strip

摘要

A polyolefin microporous membrane having a film thickness of 1 µm to 400 µm and satisfying formulas (1) and (2) or satisfying formulas (3) and (4). Equation (1): 0.7≤τ _X /τ _{Z ≤1.5} Equation (2): 0.7≤τ _Y /τ _{Z ≤1.5} τ _X : the curvature rate in the first direction along the surface of the polyolefin microporous membrane, τ _Y : the curvature rate in the second direction along the surface of the _{polyolefin microporous membrane, τ Z} : the polyolefin microporous membrane The curvature rate in the thickness direction. Equation (3): 0.5≤T _X /T _{Z ≤2.0} Equation (4): 0.5≤T _Y /T _{Z ≤2.0} T _X : Permeability index in the first direction along the surface of the polyolefin microporous membrane, T _Y : Permeability index in the second direction along the surface of the _{polyolefin microporous membrane, T Z} : In the thickness direction of the polyolefin microporous membrane Permeability indicator.