Daicel Chemical Industries, Ltd.

Fuji Photo Film Company, Limited

Atsunobu Kiyose

Hiroki Taniguchi

Shu Shimamoto

Masanori Itoh

Katsumi Hirao

Yuichiro Shuto

Ko Murakami

Toshinori Okano

Yonosuke Kato

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.

Cellulose acetate excellent in physical strength, and process for

Cellulose acetate having a high moldability and low solution viscosity in spite of having a high average degree of polymerization is obtained. The low molecular weight components of cellulose acetate (e.g., CTA having average degree of acetylation of 59.0 to 62.5%) are eluted with a washing solvent to produce a cellulose acetate having a molecular weight distribution Mw/Mn of 1 to 1.7. As the washing solvent, those swell or partially dissolve the cellulose acetate, for example, those which dissolve 0.1 to 30% by weight of cellulose acetate can be used. This solvent includes, for example, a solvent having a solubility parameter .delta. of 7 to 12.5 (ketones, ethers, organic acid, esters, etc.).

Cellulose acetate with high moldability and process for production

The composition comprising a cellulose ester including at least 10 weight % of a low-substituted cellulose ester having an average degree of substitu- tion not exceeding 2.15 and giving a 4-week decomposition rate of at least 60 weight % as determined using the amount of evolution of carbon dioxide as an indicator in accordance with ASTM 125209-91. The composition may contains a plasticizer, an aliphatic polyester, a photolysis accelerator such as anatase type titanium dioxide or a biodegradation accelerator such as organic acids and their esters. The low-substituted cellulose ester may be a cellulose ester having an average degree of polymerization from 50 to 250, an average degree of substitution from 1.0 to 2.15 and a residual alkali metal/alkaline earth metal-to-residual sulfuric acid equivalent ratio of 0.1 to 1.1. The biodegradable cellulose ester composition is suitable for the manufacture of various articles including fibrous articles such as tobacco filters.

Biodegradable cellulose ester composition and article

The composition comprising a cellulose ester including at least 10 weight % of a low-substituted cellulose ester having an average degree of substitution not exceeding 2.15 and giving a 4-week decomposition rate of at least 60 weight % as determined using the amount of evolution of carbon dioxide as an indicator in accordance with ASTM 125209-91. The composition may contains a plasticizer, an aliphatic polyester, a photolysis accelerator such as anatase type titanium dioxide or a biodegradation accelerator such as organic acids and their esters. The low-substituted cellulose ester may be a cellulose ester having an average degree of polymerization from 50 to 250, an average degree of substitution from 1.0 to 2.15 and a residual alkali metal/alkaline earth metal-to-residual sulfuric acid equivalent ratio of 0.1 to 1.1. The biodegradable cellulose ester composition is suitable for the manufacture of various articles including fibrous articles such as tobacco filters.

A process for producing a mixed cellulose ether comprising reacting a starting cellulose ether with an etherifying agent is disclosed, wherein said starting cellulose ether comprises at least 18 mol % of a 6-substituted glucose unit and at least 15 mol % of an unsubstituted glucose unit. A high utilization of the etherfifying agent can be reached. The resulting mixed cellulose ether has a high solubility in water and an aqueous solution of the resulting mixed cellulose ether has excellent properties such as flow properties and clarity.

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Hyogo, Japan

Atsunobu Kiyose