CELLULOSE ESTER AND PROCESS FOR PRODUCTION THEREOF

摘要

The invention provides a cellulose ester and a film which are useful in enhancing optical characteristics such as optical isotropy remarkably. A cellulose ester which has a total mean degree of substitution of 2.90 to 2.965, a sum total of mean degrees of substitution at the 2- and 3-positions of glucose units of 1.97 or above and a half width of compositional distribution of 0.09 or below in degree of substitution. This cellulose ester can be produced by a process for the production of cellulose ester which comprises the acylation step (i) of acylating cellulose with an acylating agent in the presence of a sulfuric acid catalyst and the aging step (ii) of aging the obtained product in the presence of a sulfuric acid catalyst, wherein the acylation in the acylation step (i) is conducted in the presence of 6.5 to 9.5 parts by weight of a sulfuric acid per 100 parts by weight of cellulose by the use of 1.40 to 2.0 molar equivalents of an acylating agent per mol of cellulosic hydroxyl.