Fibrous composite cellulosic film and method
AssigneeViskase Corporation
InventorJohn Markulin
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Abstract
A crosslinked cellulose composite film including a regenerated cellulose matrix containing a uniform dispersion of hemp fibers and a poly(ethylene oxide) plasticizer. A method for forming the film includes mixing a slurry of the hemp, poly(ethylene oxide) and a cellulose solvent with a cellulose solution, extruding the mixture, regenerating the cellulose from the solution to form the matrix containing hemp fibers, contacting with a crosslinking agent and then drying.
Claims23
A method for producing a polyol-free cellulosic film composed of a regenerated cellulose matrix containing natural cellulose fibers comprising the steps of:
- a) providing an extrudable thermoplastic composition composed of an aqueous solution of an amine oxide cellulose solvent, a nonderivatized cellulose solubilized in the solvent and an olefinic oxide polymer and the composition containing a uniform dispersion of unsolubilized cellulose fiber;
- b) extruding a film of the thermoplastic composition;
- c) washing the extruded thermoplastic composition with a nonsolvent to remove the amine oxide cellulose solvent and thereby regenerate the solubilized non derivatized cellulose to form a wet gel film comprising a continuous phase of regenerated cellulose containing the olefinic oxide polymer and the unsolubilized cellulose fiber uniformly dispersed in the continuous phase;
- d) contacting the wet gel film with a crosslinking agent;
- and
- e) drying the wet gel film in the presence of the crosslinking agent to a moisture content sufficient to activate the agent and crosslink the regenerated cellulose and unsolubilized cellulose fibers and the amount of olefinic oxide polymer in the dry film being sufficient to plasticize the dry film so as to avoid the need for an addition of a polyol to plasticize the dry film.
A crosslinked fibrous cellulosic composite film comprising a continuous phase of regenerated nonderivatized cellulose containing a uniform dispersion of unsolubilized cellulose fibers, an olefinic oxide polymer and an effective amount of a cellulose crosslinking agent, said film being formed by the extrusion of a thermoplastic composition composed of cellulose fibers dispersed in an aqueous solution of an amine oxide cellulose solvent, a nonderivatized cellulose solubilized in the solvent and an olefinic oxide polymer, the composition being sequentially extruded, washed to regenerate the solubilized nonderivatized cellulose, contacted with the crosslinking agent and then dried to activate the crosslinking agent, and said olefinic oxide polymer being a plasticizer for said film.
Dependencies are inferred from the claim text.