Weyerhaeuser Company Limited

Weyerhaeuser

W Harvey Persinger, Jr

Mengkui Luo

James E Sealey, Ii

Amar N Neogi

Vincent A Roscelli

Brian Wester

Kent Douglas Robarge

A process for making a composition for conversion to lyocell fiber where the process comprises pulping a raw material in a digester to provide an alkaline pulp, wherein the raw material comprises sawdust in an amount greater than 0 % up to 100 %; and contacting the alkaline pulp comprising cellulose and at least about 7 % hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to within the range of from about 200 to about 1100, without substantially reducing the hemicellulose content of the pulp or substantially increasing the copper number.

Process for making composition for conversion to lyocell fiber from sawdust

The present invention provides compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization (D.P.) and a narrow molecular weight distribution. Further, the present invention provides processes for making compositions, useful for making lyocell fibers, by contacting an alkaline pulp having a high hemicellulose content of at least about 7% with an oxidant sufficient to reduce the average degree of polymerization to about 200 to 1100 without substantially reducing the hemicellulose content or increasing the copper number of the pulp.

Process for making a composition for conversion to lyocell fiber from an alkaline pulp having low average degree of polymerization values

A process for making lyocell fibers including the steps of pulping raw material in a digester to provide an alkaline pulp, wherein the raw material includes sawdust in an amount greater than 0% up to 100%; contacting the alkaline pulp including cellulose and at least about 7% hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to the range of from about 200 to about 1100 without substantially reducing the hemicellulose content or substantially increasing the copper number of the pulp; and forming fibers from the pulp.

Process for making lyocell fiber from sawdust pulp

The use of low specific gravity wood from thinning operations, for example, will produce a lower brownstock viscosity for a given kappa number target. A differential of 200-cP falling ball pulp viscosity has been detected from Kraft cooks of low and high specific gravity wood. Using low specific gravity wood can reduce the bleach stage temperature and the chemical dose needed in the bleach plant to produce lyocell pulp specifications. Low specific gravity wood also increases the ability to reduce pulp viscosity to very low levels without increasing the copper number of the pulp or the concentration of carbonyl in the pulp above acceptable levels.

Use of thinnings and other low specific gravity wood for lyocell pulps method

Use of thinnings and other low specific gravity wood for lyocell products

Use of thinnings and other low specific gravity wood for lyocell products method

Use of thinnings and other low specific gravity wood for lyocell pulps

The present invention provides compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization (D.P.), wherein greater than 4% of pulp fibers have a length-weighted fiber length of less than 2.0 mm. Further, the present invention provides processes for making compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization and short fibers. The present invention also provides lyocell fibers and molded bodies made from the compositions. An advantage of the compositions are their quick dissolving nature.

Sawdust alkaline pulp having low average degree of polymerization values and method of producing the same

The present invention provides lyocell fibers made from pulp, in particular a pulp having a high hemicellulose content of at least 5%, includes cellulose that has a low average degree of polymerization of from about 200 to about 1100, a kappa number of less than 2.0, and wherein greater than 4% of pulp fibers have a length-weighted fiber length of less than 2.0 mm.

Lyocell fiber from sawdust pulp

The present invention is directed to a process for making a lyocell fiber by contacting an alkaline pulp having cellulose and at least about 7% hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to the range of from about 200 to about 1100 without substantially reducing the hemicellulose content of the pulp or increasing the copper number and then forming fibers from the pulp.

Process for making lyocell fibers from alkaline pulp having low average degree of polymerization values

The present invention provides lyocell fibers made from compositions having a high hemicellulose content of at least 5% by weight, a low kappa number of less than 2.0 and including cellulose that has a low average degree of polymerization (D.P.) value of about 200 to 1,100, and a narrow molecular weight distribution ( R) of less than 2.8.

Lyocell fiber made from alkaline pulp having low average degree of polymerization values

The present invention provides compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization (D.P.) and a narrow molecular weight distribution. Further, the present invention provides processes for making compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization and a narrow molecular weight distribution. The present invention also provides lyocell fibers containing a high proportion of hemicellulose.

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Enumclaw, WA, United States of America

W Harvey Persinger, Jr