Nanofibrillated Cellulose Fibers

Abstract

A spray dried non-hydrogen bonded (NHB) nano-fibrillated cellulose (NFC) composition and methods for preparing such composition are disclosed. The spray dried NFC with a NHB effect results in low packing density.

1 . A spray dried non-hydrogen bonded (NHB) nano-fibrillated cellulose (NFC) fiber comprising an NFC with a packing density of about 0.4 g/cc or less. 
     
     
         2 . The spray dried NHB NFC fiber according to  claim 1 , wherein the spray dried NHB NFC fiber is made from a slurry wherein the NHB NFC has an aspect ratio greater than about 20 and a fiber diameter from about 100 to about 500 nanometers. 
     
     
         3 . A method for preparing a spray dried non-hydrogen bonded (NHB) nano-fibrillated cellulose (NFC) composition comprising:
 treating a cellulose fiber with a weight % of at least about 1% or higher in water slurry with a caustic agent under a combination of temperature and pressure;   neutralizing the treated cellulose fiber with an acid;   homogenizing or ultrasonic treating the pre-treated cellulose fiber to form a NFC slurry;   dewatering the NFC slurry by a centrifugal machine to achieve [a]   a solid level at a weight % of at least about 10 or higher;   mixing the treated NFC slurry with alcohol at a ratio of NFC to alcohol 1 to 30;   reacting the treated NFC slurry with a reagent having a general formula (I) or (II) at an elevated temperature at least about 20° C. or higher for at least 30 minutes   
       
         
           
           
               
               
           
         
         wherein R1 equals a carbon containing alkane group; 
         wherein X1, Y1, Z1 are alkoxy groups, whereby these groups may be the same or different; or 
       
       
         
           
           
               
               
           
         
         wherein R2 equals a carbon containing alkane group; 
         W is either oxygen (O) or nitrogen (N) atom; 
         R3 equals a carbon containing alkane group; 
         X2, Y2, Z2 equal alkoxy groups, wherein these groups may be the same or different; 
         and thereafter drying the NFC slurry with a spray drying equipment. 
       
     
     
         4 . The method according to  claim 3 , wherein the cellulose fiber is wood pulp fiber or non-wood fiber. 
     
     
         5 . The method according to  claim 3 , wherein the acid is HCl, nitric acid, sulfuric acid, acetic acid, phosphoric acid, citric acid or a mixture thereof. 
     
     
         6 . The method according to  claim 3 , wherein the soda based alkali water slurry is about 5 weight %. 
     
     
         7 . The method according to  claim 3 , wherein the NHB NFC fiber has an aspect ratio greater than about 20. 
     
     
         8 . The method according to  claim 3 , wherein the NHB NFC fiber has an average diameter of about 100 nm to about 500 nm. 
     
     
         9 . The method according to  claim 3 , wherein the spray dried NHB NFC fiber has a packing density less than about 0.4 g/cc. 
     
     
         10 . A method for preparing a spray dried non-hydrogen bonded (NHB) nano-fibrillated cellulose (NFC) composition comprising:
 reacting a cellulose fiber with a cellulosic reactive reagent selected from the group consisting of reagents having the general Formula (III) or (IV)   
       
         
           
           
               
               
           
         
         wherein R 1  equals F, Cl, Br, or I and R 2  equals (CH 2 ) n —OH (n=1−3), (CH 2 ) n —COOH (n=1−3), C 6 H 5 —COOH, or HSO 3 X where X equals (CH 2 ) n  (n=1−3) or C 6 H 4,;  or a vinyl sulfone having the general Formula (IV) 
       
       
         
           
           
               
               
           
         
         wherein R 1  equals a hydrocarbon having from about 1 to about 5 carbon atoms and R 2  equals CH 3,  HC=CH 2,  (CH 2 ) n —CH 3  (n=1−3), (CH2) n —COOH (n=1−3), C 6 H 4 −COOH, or C 6 H 5 ; 
         treating the cellulose fiber with a caustic agent; 
         washing the cellulose fiber; 
         treating the cellulose fiber at a weight % of at least 1% or higher in water slurry with a caustic agent under a combination of temperature and pressure; 
         neutralizing the treated cellulose fiber with an acid; 
         homogenizing or ultrasonic treating the treated cellulose fiber to form a NFC slurry; 
         drying the NFC slurry by a spray drying equipment. 
       
     
     
         11 . The method according to  claim 10 , wherein the cellulose fiber is wood pulp fiber or non-wood fiber. 
     
     
         12 . The method according to  claim 10 , wherein the acid is HCl, nitric acid, sulfuric acid, acetic acid, phosphoric acid, citric acid or a mixture thereof. 
     
     
         13 . The method according to  claim 10 , wherein the soda based alkali water slurry is about 5 weight %. 
     
     
         14 . The method according to  claim 10 , wherein the NHB NFC has an aspect ratio great than about 20. 
     
     
         15 . The method according to  claim 10 , wherein the NHB NFC have an average diameter of about 100 nm to about 500 nm. 
     
     
         16 . The method according to  claim 10 , wherein the spray dried NHB NFC has a packing density less than about 0.4 g/cc.