Method for manufacturing nanofibrillated cellulose pulp and use of the pulp in paper manufacturing or in nanofibrillated cellulose composites

Abstract

A method for manufacturing pulp. The manufactured pulp includes at least 30 w-% nanofibrillated cellulose material measured from the dried pulp. A raw material is introduced to a system. The raw material includes cellulose. At least one type of an optical brightening agent is dosed as a refining additive to the system. The raw material is refined in the presence of the dosed optical brightening agent in at least one pre-refining stage or fibrillation stage to form fibrillar cellulose material.

1 . A method for manufacturing pulp, wherein the manufactured pulp contains at least 30 w-% nanofibrillated cellulose material measured from the dried pulp, the method comprising:
 introducing raw material to a system which raw material includes cellulose,   dosing at least one type of an optical brightening agent as a refining additive to the system, and   refining the raw material in the presence of the dosed optical brightening agent in at least one pre-refining stage or fibrillation stage in order to form fibrillar cellulose material.   
     
     
         2 . The method according to  claim 1 , wherein the refining is made in the presence of the dosed optical brightening agent in at least one fibrillation stage in order to form fibrillar cellulose material. 
     
     
         3 . The method according to  claim 1 , wherein manufactured pulp contains at least 40 w-%, at least 50 w-%, at least 60 w-%, or at least 70 w-% nanofibrillated cellulose material measured from the dried pulp. 
     
     
         4 . The method according to  claim 1 , wherein at least part of the raw material is selected from the following group:
 unbleached chemical pulp,   bleached chemical pulp,   unbleached chemithermo pulp, and   bleached chemithermo pulp.   
     
     
         5 . The method according to  claim 1 , wherein at least one type of the optical brightening agent is dosed before the pre-refining stage. 
     
     
         6 . The method according to  claim 1 , wherein at least one type of the optical brightening agent is added to the pre-refining stage. 
     
     
         7 . The method according to  claim 1 , wherein at least one type of the optical brightening agent is dosed before the fibrillation stage. 
     
     
         8 . The method according to  claim 1 , wherein at least one type of the optical brightening agent is dosed to the fibrillation stage. 
     
     
         9 . The method according to  claim 1 , wherein at least one dosed optical brightening agent type is selected from the group of stilbene, coumarin and pyrazoline compounds. 
     
     
         10 . The method according to  claim 1 , further comprising:
 using the pulp in nanofibrillated cellulose composites.   
     
     
         11 . The method according to  claim 1 , further comprising:
 utilizing the pulp in manufacturing of paper or paperboard including   base paper production, and   finishing stages of paper or paperboard.   
     
     
         12 . The use according to  claim 11 , wherein said finishing stages comprise coatings for the paper or paperboard.