REDUCED FURFURAL CONTENT IN POLYACRYLIC ACID 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.
1 . A method of reducing the furfural content of polyacrylic acid crosslinked cellulosic fibers, the method comprising applying hydrogen peroxide alone, in a bleaching stage subsequent to a curing stage, to polyacrylic acid crosslinked cellulosic fibers in an amount of from about 0.1 to about 20 pounds (about 0.045 to about 9.07 kg) per ADMT of fiber and at a pH of between about 4.5 and 5, wherein the amount of furfural in the treated crosslinked fibers reduces from a first value determined at least one day after the treatment of the crosslinked fibers to a second, subsequent value determined up to 21 days after treatment.
2 . The method of claim 1 , wherein hydrogen peroxide is applied to the fibers in an amount of from about 3.0 to about 10 pounds (about 1.36 to about 4.54 kg) per ADMT fiber.
3 . The method of claim 1 , wherein hydrogen peroxide is applied to the fibers in an amount of about 5 pounds (2.27 kg) per ADMT fiber.
4 . The method of claim 1 , wherein the hydrogen peroxide is applied by spraying the hydrogen peroxide alone into an air stream containing the crosslinked fibers.
5 . The method of claim 1 , wherein the reduction of furfural from the first value to the second value is at least about 25%.
6 . The method of claim 1 , wherein the reduction of furfural is at least 55% as compared to untreated polyacrylic acid crosslinked cellulosic fibers.
7 . A method of reducing the malodor associated with the presence of furfural in polyacrylic acid crosslinked fibers comprising applying hydrogen peroxide in the absence of alkaline agents to the crosslinked fibers subsequent to curing the crosslinked fibers and thereby reduce the furfural content of the crosslinked fibers by at least about 55%.
8 . The method of claim 7 , further comprising allowing the crosslinked fibers to age up to 21 days following the application of hydrogen peroxide.
9 . The method of claim 7 , wherein the hydrogen peroxide is applied to the crosslinked fibers at a pH of between about 4.5 and 5.