Weyerhaeuser Company Limited

Weyerhaeuser

Vincent A Roscelli

Amar N Neogi

Mengkui Luo

Richard A Jewell

James E Sealey, Ii

W Harvey Persinger, Jr

Paul G Gaddis

Michael James Yancey

Sen&eacute;n Camarena

John S Selby

Senen Camarena

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 lyocell nonwoven fabric having fibers characterized by pebbled surfaces and variable cross sections and diameters along the fibers and from fiber to fiber, is disclosed. The lyocell nonwoven fabric is produced by centrifugal spinning, melt blowing or spunbonding. The lyocell nonwoven fabric has fibers that can be made in the microdenier range with average weights as low as one denier or less. The lyocell nonwoven fabric has fibers with low gloss, a reduced tendency to fibrillate and have enhanced dye receptivity.

Lyocell nonwoven fabric

Cellulose containing dope is extruded through orifices and into a stream of gas moving in a direction generally parallel to the direction that the filaments are formed with varying degrees of mechanical attenuation provided to the filaments using a take-up device, such as a winder.

Meltblown process with mechanical attenuation

The present invention is directed to a pulp useful for making lyocell fibers. The pulp has a degree of polymerization from about 300 to about 1000; an alpha cellulose content of less than about 90% and in one instance can be made in a roll form. The degree of polymerization can be modified by acid hydrolysis, steam explosion; or alkaline enzymate degradation.

Cellulosic pulp having low degree of polymerization values

The present invention is directed to methods of making lyocell fibers. In particular, the process includes reducing the average degree of polymerization of a pulp to about 200 to 1100 without substantially reducing the hemicellulose content of the pulp, and reducing the copper number to less than 2.0.

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

The present invention is directed to a lyocell fiber having a high hemicellulose content. The fibers are readily cut into staple lengths and can be spun into yarns with excellent knitting and weaving characteristics which dye exceptionally well. The fibers have a cotton-like denier.

Lyocell fibers having high hemicellulose content

The invention is lyocell fiber characterized by a pebbled surface as seen at high magnification and having a variable cross section and diameter along and between fibers. The fiber is produced by centrifugal spinning, melt blowing or its spunbonding variation. The fibers can be made in the microdenier range with average weights as low as one denier or less. The fibers have inherently low gloss and can be formed into tight yarns for making fabrics of very soft hand. Alternatively, the fibers can be formed into self bonded nonwoven fabrics.

Lyocell nonwoven fabric and process for making

The present invention provides molded bodies made from a treated kraft pulp, the pulp having a high hemicellulose content or at least 7% a low copper number of less than 2, and including cellulose that has a low average degree of polymerization (D.P.) that has a range of 200 to 1100.

Molded bodies made from compositions having low degree of polymerization values

Lyocell fibers having variability and process for making

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 compositions, useful for making lyocell fibers, having a high hemicellulose content, a low lignin content and including cellulose that has a low average degree of polymerization (D.P.). Further, the present invention provides processes for making compositions, useful for making lyocell fibers, having a high hemicellulose content, a low lignin content and including cellulose that has a low average degree of polymerization. The present invention also provides lyocell fibers containing a high proportion of hemicellulose. Further, the lyocell fibers of the present invention have enhanced dye-binding properties and a reduced tendency to fibrillate.

Lyocell fibers, and compositions for making the same

The present invention is directed to lyocell fibers having a high hemicellulose content of at least 5%, a low lignin content as measured by a kappa number less than 2.0 and including cellulose that has a low average degree of polymerization (D.P.) in the range of 200 to 1100. Further, the lyocell fibers of the present invention have enhanced dye-binding properties and a reduced tendency to fibrillate.

Lyocell fibers produced from kraft 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 lyocell films, having a high hemicellulose content of at least 5%, a low copper number of less than 2, and including cellulose that has a low average degree of polymerization (D.P.) in the range of about 200 to 1100.

Lyocell film made from cellulose having low 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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Edgewood, WA, United States of America

Vincent A Roscelli