Claims
- 1. A process for producing a product cellulose acetate with a viscosity average degree of polymerization of not less than 290, having a high moldability and a molecular weight distribution Mw/Mn of 1 to 1.7 according to gel permeation chromatography, which consists essentially of the step of washing a cellulose acetate mixture of varying molecular weights with a solvent which elutes low molecular weight components from the cellulose acetate to produce the product cellulose acetate.
- 2. The process for producing a product cellulose acetate according to claim 1, wherein the washing solvent swells or partially dissolves the cellulose acetate.
- 3. The process for producing a product cellulose acetate according to claim 1, wherein the washing solvent dissolves 0.1 to 30% by weight of the cellulose acetate when the cellulose acetate is dispersed at 25.degree. C. at a solids concentration of 5% by weight.
- 4. The process for producing a product cellulose acetate according to claim 1, wherein 1 to 50% by weight of the cellulose acetate is washed out by the washing step.
- 5. The process for producing a product cellulose acetate according to claim 1, wherein the cellulose acetate is washed with a solvent having a solubility parameter .delta. of 7 to 12.5.
- 6. The process for producing a product cellulose acetate according to claim 1, wherein the washing solvent is at least one member selected from the group consisting of ketones, ethers, organic acids and esters.
- 7. The process for producing a product cellulose acetate according to claim 6, wherein the washing solvent is acetone or methyl acetate.
- 8. The process for producing a product cellulose acetate according to claim 1, wherein cellulose triacetate having an average degree of acetylation of 59.0 to 62.5% is washed with a solvent selected from the group consisting of ketones, ethers, organic acids and esters and has a solubility parameter .delta. of 8.5 to 11.5.
- 9. The process for producing a product cellulose acetate according to claim 8, wherein the solvent further comprises water or an alcohol and can elute low molecular weight components of the cellulose acetate.
- 10. A process for producing a product cellulose acetate according to claim 2, wherein the washing solvent dissolves 0.1 to 30% by weight of the cellulose acetate when the cellulose acetate is dispersed at 25.degree. C. at a solids concentration of 5% by weight.
Priority Claims (2)
Number |
Date |
Country |
Kind |
7-100711 |
Mar 1995 |
JPX |
|
7-085550 |
Apr 1995 |
JPX |
|
Parent Case Info
This application is a 371 of PCT/JP96/00862 filed on Mar. 29, 1996.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/JP96/00862 |
3/29/1996 |
|
|
11/21/1996 |
11/21/1996 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO96/30413 |
3/10/1996 |
|
|
US Referenced Citations (19)
Foreign Referenced Citations (4)
Number |
Date |
Country |
45-9074 |
Apr 1970 |
JPX |
49-5614 |
Feb 1974 |
JPX |
49-4554 |
Feb 1974 |
JPX |
59-166501 |
Sep 1984 |
JPX |
Non-Patent Literature Citations (1)
Entry |
"Effect of the degree of polymerization . . . ", Khim. Volokna, 1985, No. 3, pp. 46-47 (Derwent publication ) (1 page). |