Modified fiber from shredded pulp sheets, methods, and systems
Methods of forming crosslinked cellulose include mixing a crosslinking agent with cellulose mat fiber fragments composed of hydrogen-bonded cellulose fibers and having a solids content of about 45-95% to form a substantially homogenous mixture of non-crosslinked, individualized cellulose fibers, drying the resulting mixture to 85-100% solids, then curing the dried mixture under conditions effective to crosslink the cellulose fibers. Some of such methods may include fragmenting a cellulose fiber mat to form the mat fragments. Systems include a mixing unit (such as a high-consistency mixer) configured to form, from the mat fragments and a crosslinking agent, a substantially homogenous mixture of non-crosslinked, individualized cellulose fibers and crosslinking agent, at ambient conditions, a drying unit to dry the substantially homogenous mixture to a consistency of 85-100%, and a curing unit and to cure the crosslinking agent to form dried and cured crosslinked cellulose fibers.
1. A system, comprising:
a high consistency mixing unit being configured to form, from cellulose fiber mat fragments comprising hydrogen-bonded cellulose fibers and having a solids content of about 45-95% and a crosslinking agent, a substantially homogenous mixture of crosslinking agent and non-crosslinked cellulose fibers in individualized form, at ambient conditions and being configured to directly inject the crosslinker onto the cellulose fiber mat fragments;
a drying unit downstream of the high consistency mixing unit and configured to dry the substantially homogenous mixture to a consistency of 85-100% without curing the crosslinking agent; and
a curing unit downstream of the drying unit and configured to cure the crosslinking agent, thereby forming dried and cured crosslinked cellulose fibers.
2. The system of claim 1 , wherein the high consistency mixing unit includes apparatus selected from the group consisting of an extruder, a hydrapulper, a refiner, a deflaker, and a high-consistency mixer.
3. The system of claim 1 , wherein the high consistency mixing unit includes a high-consistency mixer.
4. The system of claim 1 , further including a fragmenting unit upstream of the high consistency mixing unit and configured to form the cellulose fiber mat fragments from a cellulose fiber mat, wherein the fragmenting unit includes one or more of a crusher, a dicer, and/or a shredder.
5. The system of claim 4 , wherein the high consistency mixing unit is configured to form, from cellulose fiber mat fragments consisting essentially of hydrogen-bonded cellulose fibers and having a solids content of about 45-95% and a crosslinking agent, said substantially homogenous mixture of non-crosslinked, individualized cellulose fibers and crosslinking agent, at ambient conditions.
6. The system of claim 4 , wherein the fragmenting unit is configured to fragment a cellulose fiber mat that is moistened.
7. The system of claim 6 , wherein the fragmenting unit is configured to moisten the cellulose fiber mat.
8. The system of claim 4 , wherein the fragmenting unit is configured to fragment a cellulose fiber mat that is a pulp sheet, paper, paperboard, nonwoven, wet lap sheet consisting of never dried or previously dried cellulose, or a combination thereof.
9. The system of claim 4 , wherein the fragmenting unit is configured to fragment a cellulose fiber mat in bale or roll form.
10. The system of claim 1 , wherein the hydrogen-bonded cellulose fibers comprise hardwood fibers.
11. The system of claim 1 , wherein the hydrogen-bonded cellulose fibers comprise eucalyptus fibers.
12. A system, comprising:
a fragmenting unit configured to form, from a hydrogen-bonded mat of cellulose fibers, cellulose fiber mat fragments comprising hydrogen-bonded cellulose fibers and having a solids content of about 60-80%;
a high consistency mixing unit downstream of the fragmenting unit and configured to form, from the cellulose fiber mat fragments and a polyacrylic acid crosslinking agent present in an amount and concentration to achieve a chemical on pulp level of about 2-14%, a substantially homogenous mixture of crosslinking agent and non-crosslinked cellulose fibers in individualized form, at ambient conditions, with the solids content of the mixture being about 50-60% and configured to directly inject the polyacrylic acid crosslinking agent onto the cellulose fiber mat fragments;
a drying unit downstream of the high consistency mixing unit and configured to dry the substantially homogenous mixture to a consistency of 85-100% without curing the crosslinking agent; and
a curing unit downstream of the drying unit and configured to cure the crosslinking agent, thereby forming dried and cured crosslinked cellulose fibers.
13. The system of claim 12 , wherein the hydrogen-bonded cellulose fibers comprise hardwood fibers.
14. The system of claim 12 , wherein the hydrogen-bonded cellulose fibers comprise eucalyptus fibers.