Abstract: A process for adjusting an intermolecular or intramolecular degree of acetyl substitution of cellulose acetate is disclosed. The process comprises ripening cellulose acetate in the presence of a catalyst, an acetyl donor, and water or an alcohol. The amount of water and the alcohol is in the range of 0.1 to 10 mol % based on the amount of the acetyl donor.

Abstract: A process for adjusting an intermolecular or intramolecular degree of acetyl substitution of cellulose acetate is disclosed. The process comprises ripening cellulose acetate in the presence of a catalyst, an acetyl donor, and water or an alcohol. The amount of water and the alcohol is in the range of 0.1 to 10 mol % based on the amount of the acetyl donor.

Abstract: A process for adjusting an intermolecular or intermolecular degree of acetyl substitution of cellulose acetate is disclosed. The process comprises ripening cellulose acetate in the presence of a catalyst, an acetyl donor, and water or an alcohol. The amount of water and the alcohol is in the range of 0.1 to 10 mol % based on the amount of the acetyl donor.

Abstract: A process for adjusting an intermolecular or intramolecular degree of acetyl substitution of cellulose acetate is disclosed. The process comprises ripening cellulose acetate in the presence of a catalyst, an acetyl donor, and water or an alcohol. The amount of water and the alcohol is in the range of 0.1 to 10 mol % based on the amount of the acetyl donor.

Abstract: A process for adjusting an intermolecular or intramolecular degree of acetyl substitution of cellulose acetate is disclosed. The process comprises ripening cellulose acetate in the presence of a catalyst, an acetyl donor, and water or an alcohol. The amount of water and the alcohol is in the range of 0.1 to 10 mol % based on the amount of the acetyl donor.

Abstract: The present invention provides a cellulose ester composition, containing 1 to 99% by weight of cellulose triacetate prepared by substituting hydroxyl groups of cellulose with acetyl and having a degree of substitution with acetyl, DSace, which satisfies the relationship: 2.7.ltoreq.DSace.ltoreq.3.0, and 99 to 1% by weight of a mixed fatty acid ester of cellulose prepared by substituting hydroxyl groups of cellulose with acetyl and acyl groups having three or more carbon atoms and having degrees of substitution with acetyl and acyl groups having three or more carbon atoms, DSace and DSacyl, respectively, which satisfy the relationships: (I) 2.20.ltoreq.DSace.ltoreq.2.95, (II) 0.05.ltoreq.DSacyl.ltoreq.0.80 and (III) 2.60.ltoreq.DSace+DSacyl.ltoreq.3.00.

Abstract: An object of the invention is to obtain cellulose acetate with improved physical properties, particularly film strength arid improved flexibility of the molded product. Cellulose acetate wherein average degree of acetylation is not less than 59%, viscosity average degree of polymerization (DP) is not less than 290, and concentrated solution viscosity (.eta.) according to the falling ball viscosity method for viscosity average degree of polymerization (DP) is expressed by the following formula (1): 2.814.times.ln(DP)-11.753.ltoreq.ln(.eta.).ltoreq.7.28.times.ln(DP)-37.059 (1) and a process for production thereof.

Abstract: Cellulose acetate propionate is a cellulose ester wherein hydroxyl groups of cellulose are substituted with acetyl and propionyl. Cellulose acetate propionate of the present invention has an amorphous index (Am) of 0.01 to 0.10. The present invention also provides cellulose acetate propionate having a degree of acetyl substitution (DSac) and a degree of propionyl substitution (DSpr) satisfying the formulas (I) to (IV).2.0<DSac.ltoreq.2.95 (I)0.05<DSpr.ltoreq.0.8 (II)2.6<DSac+DSpr.ltoreq.3.0 (III)1.

Abstract: An object of the invention is to obtain cellulose acetate having improved physical properties, particularly film strength and improved flexibility of the molded product. Cellulose acetate having an average degree of acetylation of not less than 59%, viscosity average degree of polymerization (DP) of not less than 290. and concentrated solution viscosity (.eta.) according to falling ball viscosity method for viscosity average degree of polymerization (DP) expressed by the following formula (1):2.814.times.ln(DP)-11.753.ltoreq.ln(.eta.).ltoreq.7.28.times.ln(DP)-37.059( 1)and a process for the production thereof.

Abstract: Cellulose acetate propionate is a cellulose ester wherein hydroxyl groups of cellulose are substituted with acetyl and propionyl. Cellulose acetate propionate of the present invention has an amorphous index (Am) of not more than 0.4. Cellulose acetate propionate has a degree of acetyl substitution (DSac) and a degree of propionyl substitution (DSpr), which preferably satisfy the formulas (I) to (III), and more preferably satisfy the formulas (I) to (IV). The present invention also provides a solution of cellulose acetate propionate and a cellulose acetate propionate film. (I) 2.0<DSac.ltoreq.2.95(II) 0.05<DSpr.ltoreq.0.8(III) 2.6<DSac+DSpr.ltoreq.3.0(IV) 1.