Abstract: A method for producing a tobacco filter material which is either (A) a coating process for coating the surface of a fibrous or particulate cellulose with a cellulose ester having an average substitution degree of about 2.0 to about 2.6 to give a coated cellulose, and wet webbing the coated cellulose into a sheet, or (B) a treating process for treating a naturally-occurring or regenerated cellulose fiber or particle with an organic acid and an organic acid anhydride or organic acid halide in a liquid phase to give a cellulose derivative.

Abstract: A fatty acid ester of cellulose having excellent transparency, filterability and spinnability in spite of its high content of mannose and xylose, wherein the total molar content of mannose and xylose accounts for at least 7% of that of glucose, mannose and xylose, and the amount of filtration satisfies a specified requirement. Such a fatty acid ester of cellulose is prepared by using a pulp having a low .alpha.-cellulose content as a raw material and a fatty acid corresponding to the ester as a diluent and adding an organic solvent in an amount of at least 10% by weight based on the diluent in any step during the preparation. In the preparation of cellulose diacetate, which excellent filterability and transparency, by the acetic acid process, the cellulose diacetate obtained by aging is dissolved in a solvent which can dissolve it and the resulting cellulose diacetate is recovered.

Abstract: Using a slurry containing a particulate or fibrous cellulose ester and a wood pulp with a Canadian standard freeness of 100 to 800 ml in a ratio of 10/90 to 90/10 (weight %), a tobacco filter material in the form of a sheet having a nonwoven web structure is produced. The slurry may contain a microfibrillated cellulose in a proportion of 0.1 to 10 weight % on a nonvolatile matter basis. The cellulose ester may be a cellulose acetate with a combined acetic acid in the range of 30 to 62%. This tobacco filter material in a sheet form can be applied to a tobacco filter having a high dry strength and, yet, a high degree of wet disintegratability without adversely affecting the smoking quality of tobacco. Thus, the potential environmental pollution is mitigated by the tobacco filter.

Abstract: A tobacco filter is produced by wrapping up a sheet-like filter material having a web structure and comprising a cellulose ester short staple into a rodform. As the cellulose ester short staple, a short staple that is non-crimped and/or has a modified cross section where a ratio D1/D2 of a diameter D1 of the circumscribed circle to a diameter D2 of the inscribed circle, each circle being of the cross section, of not less than 2 is used. The short staple includes e.g. a cellulose acetate fiber with an average fiber length of 1 to 10 mm and fineness of 1 to 10 deniers. The short staple may be incorporated with a beaten pulp with a Schopper-Riegler freeness of 20 to 90.degree. SR and/or a binder. The ratio of the short staple to the beaten pulp may for example be about 90/10 to 20/80 (by weight).

Abstract: A tobacco smoke filter material comprises a fibrillated cellulose ester fiber with an average fiber diameter of 15 to 250 .mu.m and a BET specific surface area of 0.5 to 4.5 m.sup.2 /g. The fibrous cellulose ester content of the material may for example be not less than 20 weight %. The cellulose ester fiber is provided by, for example, extruding a cellulose ester solution from a nozzle into a precipitating agent for the particular cellulose ester and subjecting the extrudate to a shear force. This filter material can be used in the form of, for example, a filament, web or sheet to provide a tobacco smoke filter which assures good smoking qualities and excellent wet disintegratability.

Abstract: A tobacco filter material containing fibers which have a core and a surface layer which surrounds the core, wherein the core comprises a non-esterified cellulose and the surface layer comprises a cellulose ester. The fiber may be (A) a cellulose fiber coated with a cellulose ester or (B) a fibrous cellulose derivative with its surface layer esterified by an organic acid and having an average degree of substitution of not more than 1.5. Wood pulp can be used as the cellulose fiber and the amount of the cellulose ester in the coated cellulose (A) is 0.1% by weight or more. The cellulose derivative (B) has its surface layer esterified with an organic acid and retains a non-esterified core portion. This cellulose derivative may be obtained, for example, by the non-catalytic liquid phase treatment of a cellulose fiber with an organic acid and an organic acid anhydride or halide.

Abstract: Using a slurry containing a particulate or fibrous cellulose ester and a wood pulp with a Canadian standard freeness of 100 to 800 ml in a ratio of 10/90 to 90/10 (weight %), a tobacco filter material in the form of a sheet having a nonwoven web structure is produced. The slurry may contain a microfibrillated cellulose in a proportion of 0.1 to 10 weight % on a nonvolatile matter basis. The cellulose ester may be a cellulose acetate with a combined acetic acid in the range of 30 to 62%. This tobacco filter material in a sheet form can be applied to a tobacco filter having a high dry strength and, yet, a high degree of wet disintegratability without adversely affecting the smoking quality of tobacco. Thus, the potential environmental pollution is mitigated by the tobacco filter.

Abstract: A tobacco smoke filter material has a fibrillated cellulose ester fiber with an average fiber diameter of 15 to 250 .mu.m and a BET specific surface area of 0.5 to 4.5 m.sup.2 /g. The fibrous cellulose ester content of the material may for example be not less than 20 weight %. The cellulose ester fiber is provided by, for example, extruding a cellulose ester solution from a nozzle into a precipitating agent for the particular cellulose ester and subjecting the extrudate to a shear force. This filter material can be used in the form of, for example, a filament, web or sheet to provide a tobacco smoke filter which assures good smoking qualities and excellent wet disintegratability.

Abstract: A tobacco filter is produced by wrapping up a sheet-like filter material having a web structure and comprising a cellulose ester short staple into a rod-form. As the cellulose ester short staple, a short staple that is non-crimped and/or has a modified cross section where a ratio D1/D2 of a diameter D1 of the circumscribed circle to a diameter D2 of the inscribed circle, each circle being of the cross section, of not less than 2 is used. The short staple includes e.g. a cellulose acetate fiber with an average fiber length of 1 to 10 mm and fineness of 1 to 10 deniers. The short staple may be incorporated with a beaten pulp with a Schopper-Riegler freeness of 20 to 90.degree. SR and/or a binder. The ratio of the short staple to the beaten pulp may for example be about 90/10 to 20/80 (by weight).