Methods and systems for processing cellulose-containing materials and isolating cellulose molecules; methods for regenerating cellulosic fibers

Abstract

Methods and systems of the present invention use cellulose-containing materials, which may include post-consumer waste garments, scrap fabric and/or various biomass materials as a raw feed material to produce isolated cellulose molecules having desirable properties that can be used in the textile and apparel industries, and in other industries. A multi-stage process is provided, in which cellulose-containing feed material is subjected to one or more pretreatment stages, followed by a pulping treatment, to isolate cellulose molecules. The isolated cellulose molecules may be used in a variety of downstream applications. In one application, isolated cellulose molecules are extruded to provide regenerated cellulose fibers having desirable (and selectable) properties that are usable in various industrial applications, including textile production.

Description

REFERENCE TO RELATED PATENT APPLICATIONS[0001]This application is a continuation-in-part application of U.S. patent application Ser. No. 14 / 255,886, filed Apr. 17, 2014, which claims priority from U.S. Provisional Patent Application No. 61 / 812,931, filed Apr. 17, 2013. The disclosures of the previous applications are incorporated by reference herein in their entireties.FIELD[0002]The present disclosure relates to methods and systems for processing cellulose-containing materials such as textiles, including textile garments (used and un-used) and scraps, biomass, wood pulp, and the like and for isolating cellulose molecules for use in a variety of downstream applications. In particular applications, the present disclosure relates to methods and systems for treatment of cellulose-containing materials to isolate cellulose molecules and to produce regenerated polymers, fibers, and / or fabrics from the isolated cellulose molecules. Recycling and regeneration of textiles is described in det...

AI Technical Summary

Benefits of technology

[0012]Isolated cellulose polymers produced using the processes described herein may be used in a variety of downstream applications, as described in more detail below and, in some embodiments, may be extruded to form regenerated cellulosic fibers. In some aspects, isolated cellulose polymers may be re-generated to provide longer chain polymers and fibers (or polymers and fibers having other desirable characteristics different from the characteristics of the cellulose-containing feedstock) that are useful in various industrial processes, including textile production. In addition to employing a raw feedstock materials that are typically discarded (wasted, at a cost), processing steps having generally low environmental impacts are preferred.

Problems solved by technology

This cycle wastes valuable materials and the considerable resources required to produce them, and it exacerbates waste disposal issues.

Natural fibers, including cotton, have a generally high and variable raw material cost due, in part, to natural disasters and climate unpredictability, regional socio-economic and political instability, human rights issues, and resource requirements.

Growing and harvesting cotton fibers is resource-intensive.

Growing cotton frequently involves heavy pesticide use, significant land resources, and produces significant levels of heat-trapping gases.

With demand for agricultural land use increasing and fresh water supplies decreasing, the cost of producing natural cotton is increasing.

At some point, the current scale of cotton production may become unprofitable and unsustainable.

Re-processing methods that convert used cotton into rags, mattress ticking, seat stuffing, insulating materials, and the like are also available, but these processing methods have been adopted in limited applications because the value of the converted material is relatively low.

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