Method for preparing cellulose acetate fibers
AssigneeEastman Chemical Company
InventorsBobby Lynn Bernard, Max Ray Davis
Life of this patent
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Abstract
A method for producing an organic cellulose derivative fibrillated fiber includes the steps of mixing a cellulose ester containing stream and a coagulant stream in a first zone of relatively moderate turbulence to produce a slurry containing cellulose ester fibers, passing the slurry containing cellulose ester fibers to a second zone having relatively low turbulence for a sufficient time to increase the hardness of the cellulose ester fiber; and passing the cellulose derivative fibers through a third zone having relatively high shear to produce a fibrillated fiber having a diameter of about 0.5 to about 50 microns and a degree of fibrillation greater than about 6.
Claims20
A method for producing an organic cellulose derivative fibrillated fiber comprising;
- a. mixing a cellulose ester containing stream and a coagulant stream in a first zone of relatively moderate turbulence to produce a slurry containing cellulose ester fibers, wherein said first zone of moderate turbulence is produced by a centrifugal pump;
- b. passing said slurry containing cellulose ester fibers to a second zone having relatively low turbulence for a sufficient time to increase the hardness of said cellulose ester fiber;
- and
- c. passing said cellulose derivative fibers through a third zone having relatively high shear to produce a fibrillated fiber having a degree of fibrillation greater than about 6.
A method for producing a fibrillated cellulose acetate fiber comprising;
- a. mixing a cellulose acetate acid dope stream and a coagulant stream in a first zone of relatively moderate turbulence to produce a slurry containing cellulose acetate fibers, wherein said first zone of moderate turbulence is produced by a centrifugal pump;
- b. passing said slurry containing cellulose acetate fibers to a second zone having relatively low turbulence for a sufficient time to increase the hardness of said cellulose acetate fibers;
- c. passing said cellulose acetate fibers through a third zone having relatively high shear to produce fibrillated fibers having a mean diameter of about 0.5 to about 20 microns and a degree of fibrillation greater than about 6;
- and
- d. transferring said fibrillated fibers to a forth zone having a relatively low turbulence for a period sufficient for the cellulose acetate fiber to harden.
A method for producing a fibrillated cellulose acetate fiber comprising;
- a. mixing an acid dope stream from a hydrolysis step of a secondary cellulose acetate process and a coagulant stream in a first zone of relatively moderate turbulence to produce a slurry containing cellulose acetate fibers, wherein said first zone of moderate turbulence is produced by a centrifugal pump;
- b. passing said slurry containing cellulose acetate fibers to a second zone having relatively low turbulence for a time of about 0.5 minutes to about 5 minutes to increase the hardness of said cellulose acetate fibers;
- c. passing said cellulose acetate fibers through a third zone having relatively high shear to produce fibrillated fibers having a mean diameter of about 2 to about 10 microns, a degree of fibrillation greater than about 6 and less than about 5 % shives per sample analysis;
- and
- d. transferring said fibrillated fibers to a forth zone having a relatively low turbulence for a time of about 5 minutes to about 60 minutes for the cellulose acetate fiber to harden.
Dependencies are inferred from the claim text.