To improve the efficiency of cleaning an org. acid contained in fibrillated cellulose ester, efficiently clean it with a small amt. of a cleaning soln., and inhibit a free acid from appearing.
A cellulose ester soln. contg. an org. acid (acetic acid) is extruded from nozzles into a precipitant and is subjected to shearing force to form a fibrillated cellulose ester. The resultant cellulose ester slurry is subjected to disaggregation or cracking and is cleaned. The fibrillated cellulose ester is then treated with an alkali (ammonia, an alkali metal, and an alkaline earth metal), and a liq. phase of the wet fibrillated cellulose ester is adjusted to a pH of 5-9. The disaggregation or cracking treatment may be done with a disaggregation or cracking machine having rotating blades and stationary teeth installed with a clearance of 10-1,000 μm. An org. acid contained in a cleaning filtrate may be recovered in an acid recovery step.
FUKUI TOSHIFUMI
KAMINAKAI HIROAKI
Next Patent: WATER-SOLUBLE TRICARBOXYPOLYSACCHARIDE