Absorbent sheet incorporating regenerated cellulose microfiber

An absorbent paper sheet comprising a pulp-derived papermaking fiber and up to 75% by weight fibrillated regenerated cellulose microfiber having a CSF value of less than 100 ml, wherein the absorbent sheet has an absorbency of at least 4 g/g, and wherein the regenerated cellulose is prepared from a cellulosic dope of dissolved cellulose comprising a solvent selected from:

• tertiary amine N-oxides;
• cellulose dissolving imidazolium salts;
• cellulose dissolving pyridinium salts;
• cellulose dissolving pyridazinium salts;
• cellulose dissolving pyrimidinium salts;
• cellulose dissolving pyrazinium salts;
• cellulose dissolving pyrazolium salts;
• cellulose dissolving oxazolium salts;
• cellulose dissolving 1, 2,3-triazolium salts;
• cellulose dissolving 1,2,4-triazolium salts;
• cellulose dissolving thiazolium salts;
• cellulose dissolving piperidinium salts;
• cellulose dissolving pyrrolidinium salts;
• cellulose dissolving quinolinium salts;
• and cellulose dissolving isoquinolinium salts, with the further proviso that the sheet includes more than 25% by weight fibrillated regenerated cellulose microfiber having a CSF value of less than 100 mil.

An absorbent paper sheet comprising pulp-derived papermaking fiber and up to 75% by weight of fibrillated regenerated cellulose microfiber having a CSF value of less than 100 ml, wherein the fibrillated regenerated cellulose microfiber has a fiber count greater than 50 million fibers/gram, and wherein the regenerated cellulose is prepared from a cellulosic dope of dissolved cellulose comprising a solvent selected from:

• tertiary amine N-oxides;
• cellulose dissolving imidazolium salts;
• cellulose dissolving pyridinium salts;
• cellulose dissolving pyridazinium salts;
• cellulose dissolving pyrimidinium salts;
• cellulose dissolving pyrazinium salts;
• cellulose dissolving pyrazolium salts;
• cellulose dissolving oxazolium salts;
• cellulose dissolving 1,2,3-triazolium salts;
• cellulose dissolving 1,2,4-triazolium salts;
• cellulose dissolving thiazolium salts;
• cellulose dissolving piperidinium salts;
• cellulose dissolving pyrrolidinium salts;
• cellulose dissolving quinolinium salts;
• and cellulose dissolving isoquinolinium salts, with the proviso that the sheet includes more than 25% by weight fibrillated regenerated cellulose microfiber having a CSF value of less than 100 mil.

An absorbent cellulosic sheet, comprising:

• (a) cellulosic pulp-derived papermaking fibers;
• and
• (b) fibrillated regenerated cellulose fibers in an amount of up to 75% by weight, wherein the regenerated cellulose is prepared from a cellulosic dope of dissolved cellulose comprising a solvent selected from:
• tertiary amine N-oxides;
• cellulose dissolving imidazolium salts;
• cellulose dissolving pyridinium salts;
• cellulose dissolving pyridazinium salts;
• cellulose dissolving pyrimidinium salts;
• cellulose dissolving pyrazinium salts;
• cellulose dissolving pyrazolium salts;
• cellulose dissolving oxazolium salts;
• cellulose dissolving 1,2,3-triazolium salts;
• cellulose dissolving 1,2,4-triazolium salts;
• cellulose dissolving thiazolium salts;
• cellulose dissolving piperidinium salts;
• cellulose dissolving pyrrolidinium salts;
• cellulose dissolving quinolinium salts;
• and cellulose dissolving isoquinolinium salts,
• said fibrillated regenerated cellulose fibers having a number average fibril width of less than 4 μm, with the proviso that the sheet includes more than 25% by weight fibrillated regenerated cellulose microfiber having a CSF value of less than 175 mil.

An absorbent cellulosic sheet, comprising:

• (a) cellulosic pulp-derived papermaking fibers;
• and
• (b) fibrillated regenerated cellulose fibers in an amount of up to 75% by weight, wherein the regenerated cellulose is prepared from a cellulosic dope of dissolved cellulose comprising a solvent selected from:
• tertiary amine N-oxides;
• cellulose dissolving imidazolium salts;
• cellulose dissolving pyridinium salts;
• cellulose dissolving pyridazinium salts;
• cellulose dissolving pyrimidinium salts;
• cellulose dissolving pyrazinium salts;
• cellulose dissolving pyrazolium salts;
• cellulose dissolving oxazolium salts;
• cellulose dissolving 1,2,3-triazolium salts;
• cellulose dissolving 1,2,4-triazolium salts;
• cellulose dissolving thiazolium salts;
• cellulose dissolving piperidinium salts;
• cellulose dissolving pyrrolidinium salts;
• cellulose dissolving quinolinium salts;
• and cellulose dissolving isoquinolinium salts,
• said fibrillated regenerated cellulose fibers having a number average fibril length of less than 500 μm, with the proviso that the sheet includes more than 25% by weight fibrillated regenerated cellulose microfiber having a CSF value of less than 100 mil.