| abstract |
A porous hollow yarn being composed of a vinylidene fluoride based resin having a weight average molecular weight of 300,000 or more, characterized in that, in the linear relationship formula between a coefficient of water permeability F (m3/m2·day), as measured under conditions of a pressure difference of 100 kPa and a water temperature of 25°C and in the range of a test length L = 0.2 to 0.8 (m), and a test length L: F = C·L + F0 (formula 1), the requirements (a) to (d): (a) an average slope C (/day) is -20 ≤ C ≤ 0, (b) an intercept (base water permeability) F0(m3/m2·day) is F0 ≥ 30, (c) the relationship between F0(m3/m2·day) and average pore diameter P (μm) as measured according to the half dry method is F0/P ≥ 300, and (d) the outer diameter is 3 mm or less are satisfied. The above porous hollow yarn exhibits a coefficient of water permeability which is enhanced in that per a piece of yarn and is reduced in the dependency on the length thereof, and exhibits enhanced treatment efficiency per volume when it is used as a filtration module, and thus is suitably used as a precise filtration member. |