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.

Bleached polyacrylic acid crosslinked cellulose fibers with reduced furfural content are disclosed. The reduced furfural content is accompanied by a strong reduction of malodor associated with crosslinked fibers. Methods of furfural reduction include treatment with hydrogen peroxide in the absence of alkaline or other bleaching agents subsequent to curing polyacrylic acid crosslinked cellulose fibers. Some embodiments of treated polyacrylic acid crosslinked cellulose fibers have a furfural content lower than 1.3 ppm. In some embodiments, the reduction of furfural content of the treated crosslinked fibers compared to untreated crosslinked fibers is at least 55%. in some embodiments, furfural content decreases with aging of the treated crosslinked fibers.

Bleached polyacrylic acid crosslinked cellulose fibers with reduced furfural content are disclosed. The reduced furfural content is accompanied by a strong reduction of malodor associated with crosslinked fibers. Methods of furfural reduction include treatment with hydrogen peroxide in the absence of alkaline or other bleaching agents subsequent to curing polyacrylic acid crosslinked cellulose fibers. Some embodiments of treated polyacrylic acid crosslinked cellulose fibers have a furfural content lower than 1.3 ppm. In some embodiments, the reduction of furfural content of the treated crosslinked fibers compared to untreated crosslinked fibers is at least 55%. in some embodiments, furfural content decreases with aging of the treated crosslinked fibers.

Bleached polycrylic acid crosslinked cellulose fibers with reduced furfural content are disclosed. The reduced furfural content is accompanied by a strong reduction of malodor associated with crosslinked fibers. Methods of furfural reduction include treatment with hydrogen peroxide in the absence of alkaline or other bleaching agents subsequent to curing polyacrylic acid crosslinked cellulose fibers. Some embodiments of treated polycrylic acid crosslinked cellulose fibers have a furfural content lower than 1.3 ppm. In some embodiments, the reduction of furfural content of the treated crosslinked fibers compared to untreated crosslinked fibers is at least 55%. in some embodiments, furfural content decreases with aging of the treated crosslinked fibers.

Bleached polycrylic acid crosslinked cellulose fibers with reduced furfural content are disclosed. The reduced furfural content is accompanied by a strong reduction of malodor associated with crosslinked fibers. Methods of furfural reduction include treatment with hydrogen peroxide in the absence of alkaline or other bleaching agents subsequent to curing polyacrylic acid crosslinked cellulose fibers. Some embodiments of treated polycrylic acid crosslinked cellulose fibers have a furfural content lower than 1.3 ppm. In some embodiments, the reduction of furfural content of the treated crosslinked fibers compared to untreated crosslinked fibers is at least 55%. in some embodiments, furfural content decreases with aging of the treated crosslinked fibers.

An aqueous composition includes water and a cationic polymeric resin having at least one reactive aldehyde group and formed from the reaction of glyoxal and a polymer. The polymer comprises at least one acrylamide repeating unit and at least one cationic repeating unit wherein a number of reactive aldehyde equivalents divided by a number of equivalents of residual glyoxal based on the total weight of the polymer is greater than about 1.2, wherein prior to reaction the polymer has greater than about 50 mole % acrylamide repeat units and from about 2 to about 30 mole % cationic repeating units, wherein greater than about 5 mole % of the acrylamide repeating units are converted to reactive aldehyde groups in the cationic polymer resin; and wherein the composition exhibits a viscosity gain of less than about 200%.

The present invention provides aqueous compositions for treating fluff pulp comprising (i) one or more acrylic acid polymers containing phosphinate groups and having a weight average molecular weight of from 1,000 to 6,000 and (ii) from 5 to 50 wt. %, based on the total solids weight of the aqueous compositions, of one or more polyethylene glycols, having a formula weight of from 150 to 7,000, or, preferably, from 200 to 600. The present invention also provides individualized, intrafiber crosslinked cellulosic fibers comprising the cellulosic fiber and, in cured form, the aqueous compositions, as well as methods of making the individualized, intrafiber crosslinked cellulosic fibers.

The present invention provides aqueous compositions for treating fluff pulp comprising (i) one or more acrylic acid polymers containing phosphinate groups and having a weight average molecular weight of from 1,000 to 6,000 and (ii) from 5 to 50 wt. %, based on the total solids weight of the aqueous compositions, of one or more polyethylene glycols, having a formula weight of from 150 to 7,000, or, preferably, from 200 to 600. The present invention also provides individualized, intrafiber crosslinked cellulosic fibers comprising the cellulosic fiber and, in cured form, the aqueous compositions, as well as methods of making the individualized, intrafiber crosslinked cellulosic fibers.

In a method for preparing glyoxylated polyacrylamide, in which an aqueous solution of polyacrylamide is supplemented with ethanedial (glyoxal) under stirring by means of a circulation pump, the reaction is started by the addition of a base, at a basic pH value above 8, and is allowed to react under stirring and/or circulating, whereupon the reaction is stopped by the addition of an acid under stirring and/or circulating after completion of a predetermined reaction time, wherein the method is per as a discontinuous method in which the quantitative reaction of ethanedial with an excess amount of polyacrylamide in an aqueous basic medium is controlled and/or regulated by at least one, of the following factors: a) turbidity measurement b) adaptation as a function of the temperature c) pH adaptation as a function of the reaction time d) drop of pH the value, or e) current consumption of the circulation pump.

In a method for preparing glyoxylated polyacrylamide, in which an aqueous solution of polyacrylamide is supplemented with ethanedial (glyoxal) under stirring by means of a circulation pump, the reaction is started by the addition of a base, at a basic pH value above 8, and is allowed to react under stirring and/or circulating, whereupon the reaction is stopped by the addition of an acid under stirring and/or circulating after completion of a predetermined reaction time, wherein the method is per as a discontinuous method in which the quantitative reaction of ethanedial with an excess amount of polyacrylamide in an aqueous basic medium is controlled and/or regulated by at least one, of the following factors: a) turbidity measurement b) adaptation as a function of the temperature c) pH adaptation as a function of the reaction time d) drop of pH the value, or e) current consumption of the circulation pump.