Patent ID: 7863439
Filing Date: 2011-01-04
Classification: C08B,C08J,C08L,Y10T

Abstract:
1. A cellulose ester fulfilling the following formula: wherein (A) is the total molar amount of residual sulfuric acid in 1 gram of said cellulose ester, (B) is the total molar amount of calcium contained in 1 gram of said cellulose ester, the total amount (A) of residual sulfuric acid in 1 gram of said cellulose ester is from 1×10 and wherein a heat stability of the cellulose ester under wet conditions, or heat resistance under wet conditions, is not more than 0.08% based on the following formula: % heat stability or resistance under wet conditions=(C−D)×F×0.06/sample weight in grams wherein “C”: a titer in terms of ml of 0.01N-NaOH aqueous solution, D”: a titer in terms of ml of 0.01N-NaOH aqueous solution in the blank test, and “F”: a factor of 0.01N-NaOH aqueous solution wherein said cellulose ester is prepared by acetylating a cellulose in the presence of a sulfuric acid catalyst; hydrolyzing the acetylated cellulose to obtain the cellulose acetate; neutralizing said sulfuric acid at least in part with a neutralizing agent before or after the hydrolyzing step, wherein the neutralizing agent is a magnesium containing component; and adding a calcium component after the neutralizing step to thereby obtain the cellulose ester.