Wood pulp fiber morphology modifications through thermal drying

Abstract

A method of modifying a two-dimensional, flat fiber morphology of a never-been-dried wood pulp into a three-dimensional twisted fiber morphology without the aid of a chemical cross-linker. The method includes the steps of treating a never-been-dried wood pulp fiber slurry with a drying aid and thermally drying the wood pulp fiber slurry. The method may alternatively, or additionally, include the steps of spray drying a wood pulp fiber slurry and/or a slurry of a hydrophilic material, and flash drying the spray dried wood pulp fiber slurry and/or slurry of hydrophilic material.

1 . A method of modifying a two-dimensional, flat fiber morphology of a never-been-dried wood pulp into a three-dimensional twisted fiber morphology, comprising the steps of: 
 treating a wood pulp fiber slurry with a drying aid; and    thermally drying the wood pulp fiber slurry at a temperature of at least 200 degrees Celsius.    
     
     
         2 . The method of  claim 1 , wherein the wood pulp fiber slurry is thermally dried at a temperature of at least 250 degrees Celsius.  
     
     
         3 . The method of  claim 1 , wherein the wood pulp fiber slurry is thermally dried at a temperature of at least 300 degrees Celsius.  
     
     
         4 . The method of  claim 1 , wherein the wood pulp fiber slurry is subjected to thermal drying for between about 0.1 and about 20 seconds.  
     
     
         5 . The method of  claim 1 , wherein the drying aid comprises a surfactant.  
     
     
         6 . The method of  claim 5 , wherein the surfactant is selected from the group consisting of an anionic surfactant, a cationic surfactant, and a combination of an anionic surfactant, a cationic surfactant, and a non-ionic surfactant.  
     
     
         7 . The method of  claim 1 , further comprising the step of subjecting the wood pulp fiber slurry to a refining treatment prior to treating the wood pulp fiber slurry with the drying aid.  
     
     
         8 . The method of  claim 1 , wherein the thermal drying step is carried out using a flash dryer.  
     
     
         9 . The method of  claim 8 , further comprising the step of fluffing the wood pulp fiber slurry prior to flash drying the wood pulp fiber slurry.  
     
     
         10 . The method of  claim 8 , further comprising the step of removing water from the wood pulp fiber slurry, up to about 30% to about 50% consistency by weight, prior to flash drying the wood pulp fiber slurry.  
     
     
         11 . The method of  claim 1 , wherein the thermally dried wood pulp fiber slurry comprises at least 80% twisted fibers.  
     
     
         12 . The method of  claim 1 , wherein the thermally dried wood pulp fiber slurry comprises at least 85% twisted fibers.  
     
     
         13 . The method of  claim 1 , wherein the thermally dried wood pulp fiber slurry comprises at least 90% twisted fibers.  
     
     
         14 . The method of  claim 1 , wherein a water retention value of the wood pulp is at least 0.8 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         15 . The method of  claim 1 , wherein a water retention value of the wood pulp is at least 1.0 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         16 . The method of  claim 1 , wherein a water retention value of the wood pulp is at least 1.1 grams water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         17 . The method of  claim 1 , wherein an average dry fiber twist count of the wood pulp is at least about 2.0 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         18 . The method of  claim 1 , wherein an average wet fiber twist count of the wood pulp is at least about 1.5 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         19 . A cellulosic, fibrous material comprising fibers modified according to the method of  claim 1 .  
     
     
         20 . A method of modifying a two-dimensional, flat fiber morphology of a never-been-dried wood pulp into a three-dimensional twisted fiber morphology, comprising the steps of: 
 spray drying a wood pulp fiber slurry; and    flash drying the spray dried wood pulp fiber slurry.    
     
     
         21 . The method of  claim 20 , wherein the flash drying step includes thermally drying the wood pulp fiber slurry at a temperature of at least 180 degrees Celsius.  
     
     
         22 . The method of  claim 20 , wherein the flash drying step includes thermally drying the wood pulp fiber slurry at a temperature of at least 200 degrees Celsius.  
     
     
         23 . The method of  claim 20 , wherein the flash drying step includes thermally drying the wood pulp fiber slurry at a temperature of at least 220 degrees Celsius.  
     
     
         24 . The method of  claim 20 , wherein the wood pulp fiber slurry has a consistency of between about 0.1% and about 10% prior to spray drying the wood pulp fiber slurry.  
     
     
         25 . The method of  claim 20 , wherein the spray drying is carried out until the wood pulp fiber slurry reaches a consistency of between about 15% and about 50% consistency by weight.  
     
     
         26 . The method of  claim 20 , further comprising the step of subjecting the wood pulp fiber slurry to a refining treatment prior to spray drying the wood pulp fiber slurry.  
     
     
         27 . The method of  claim 20 , wherein the flash dried wood pulp fiber slurry comprises at least 80% twisted fibers.  
     
     
         28 . The method of  claim 20 , wherein the flash dried wood pulp fiber slurry comprises at least 85% twisted fibers.  
     
     
         29 . The method of  claim 20 , wherein the flash dried wood pulp fiber slurry comprises at least 90% twisted fibers.  
     
     
         30 . The method of  claim 20 , wherein a water retention value of the wood pulp is at least 0.8 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         31 . The method of  claim 20 , wherein a water retention value of the wood pulp is at least 1.0 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         32 . The method of  claim 20 , wherein a water retention value of the wood pulp is at least 1.1 grams water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         33 . The method of  claim 20 , wherein an average dry fiber twist count of the wood pulp is at least about 2.0 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         34 . The method of  claim 20 , wherein an average wet fiber twist count of the wood pulp is at least about 1.5 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         35 . A cellulosic, fibrous material comprising fibers modified according to the method of  claim 20 .  
     
     
         36 . A method of modifying a two-dimensional, flat fiber morphology of a slurry of a hydrophilic material into a three-dimensional twisted fiber morphology, comprising the steps of: 
 spray drying a slurry of a hydrophilic material; and    flash drying the spray dried slurry of the hydrophilic material.    
     
     
         37 . The method of  claim 36 , wherein the hydrophilic material is selected from the group consisting of microcrystalline cellulose, microfibrillated cellulose, wood pulp fiber, and combinations thereof.  
     
     
         38 . The method of  claim 36 , wherein the flash drying step includes thermally drying the slurry of the hydrophilic material at a temperature of at least 200 degrees Celsius.  
     
     
         39 . The method of  claim 36 , wherein the flash drying step includes thermally drying the slurry of the hydrophilic material at a temperature of at least 250 degrees Celsius.  
     
     
         40 . The method of  claim 36 , wherein the flash drying step includes thermally drying the slurry of the hydrophilic material at a temperature of at least 300 degrees Celsius.  
     
     
         41 . The method of  claim 36 , wherein the slurry of the hydrophilic material is subjected to flash drying for between about 0.1 and about 20 seconds.  
     
     
         42 . The method of  claim 36 , wherein the slurry of hydrophilic material has a consistency of between about 0.1% and about 10% prior to spray drying the slurry of hydrophilic material.  
     
     
         43 . The method of  claim 36 , wherein the spray drying is carried out until the slurry of the hydrophilic material reaches a consistency of between about 15% and about 80% consistency by weight.  
     
     
         44 . The method of  claim 36 , further comprising the step of subjecting the slurry of the hydrophilic material to a refining treatment prior to spray drying the slurry of the hydrophilic material.  
     
     
         45 . The method of  claim 36 , wherein the flash dried slurry of the hydrophilic material comprises at least 80% twisted fibers.  
     
     
         46 . The method of  claim 36 , wherein the flash dried slurry of the hydrophilic material comprises at least 85% twisted fibers.  
     
     
         47 . The method of  claim 36 , wherein the flash dried slurry of the hydrophilic material comprises at least 90% twisted fibers.  
     
     
         48 . The method of  claim 36 , wherein a water retention value of the hydrophilic material is at least 0.8 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         49 . The method of  claim 36 , wherein a water retention value of the hydrophilic material is at least 1.0 gram water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         50 . The method of  claim 36 , wherein a water retention value of the hydrophilic material is at least 1.1 grams water/gram dry fiber as a result of being modified from two-dimensional to three-dimensional.  
     
     
         51 . The method of  claim 36 , wherein an average dry fiber twist count of the hydrophilic material is at least about 2.0 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         52 . The method of  claim 36 , wherein an average wet fiber twist count of the hydrophilic material is at least about 1.5 twist nodes per millimeter as a result of being modified from two-dimensional to three-dimensional.  
     
     
         53 . A cellulosic, fibrous material comprising hydrophilic material modified according to the method of  claim 36.