Base material for liquid filters
AssigneeTeijin Limited
InventorsAyumi Iwai, Koji Furuya, Yu Nagao, Yoshikazu Ikuta
Life of this patent
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Abstract
The present disclosure provides a substrate for a liquid filter, including: a polyolefin microporous membrane, in which a mean flow pore size in a pore size distribution of the polyolefin microporous membrane measured by a half dry method according to gas-liquid phase substitution is from 1 nm to 50 nm, a calcium content in the polyolefin microporous membrane is 2,000 ppb or less, and a ratio of a tensile elongation in a longitudinal direction (MD) to a tensile elongation in a width direction (TD) perpendicular to the longitudinal direction (MD/TD tensile elongation ratio) of the polyolefin microporous membrane is from 0.47 to less than 0.96 or from more than 1.25 to 7.
Claims9
A substrate for a liquid filter, comprising:
- a polyolefin microporous membrane, wherein:
- a mean flow pore size in a pore size distribution of the polyolefin microporous membrane, measured by a half dry method according to gas-liquid phase substitution, is from 1 nm to 50 nm,
- a calcium content in the polyolefin microporous membrane is 2,000 ppb or less,
- a ratio of a tensile elongation in a longitudinal direction (MD), to a tensile elongation in a width direction (TD) perpendicular to the longitudinal direction (MD/TD tensile elongation ratio), of the polyolefin microporous membrane is from 0.47 to less than 0.96 or from more than 1.25 to 7,
- a polyolefin configuring the polyolefin microporous membrane is a polyethylene composition containing a high-molecular-weight polyethylene having a weight-average molecular weight of from 5,100,000 to 6,000,000 and a low-molecular-weight polyethylene having a weight-average molecular weight of from 650,000 to 800,000, and
- a blending ratio of the high-molecular-weight polyethylene and the low-molecular-weight polyethylene is from 50:50 to 80:20 by mass ratio.
Dependencies are inferred from the claim text.