PURPOSE: To collect the impurity particles having ≤10μm diameter by using a polyvinyl acetal contg. ≥3wt.% of the glass fiber with the average diameter specified and having ≤50μm average pore diameter and ≥80vol.% porosity to form the filter.
CONSTITUTION: A specified amt. of the glass fiber having 0.1-1.2μm average diameter is dispersed in water, and further a specified amt. of PVA is added to the dispersion and dissolved. A dispersion of starch in water is then added, a defoaming agent, the aldehydes as a cross-linking agent and the acids as catalyst are added, and the materials are uniformly mixed. The liq. mixture is castes into a cylindrical framework, heated to about 50-80°C, acetalized and washed with water to form a cartridge filter consisting of a polyvinyl acetal- based porous body. Besides, the porous body contains ≥3wt.% of the above- mentioned glass fiber and has ≤50μm average pore diameter and ≥80vol.% porosity.
KOBAYASHI MASANORI
SASAKI YASUOKI
TOMITA YOJI
KITANI SUSUMU
OGIWARA TAKESHI
MIYOSHI KAZUTAKA
ABE MASAAKI
NIPPON MUKI KK