US2006151134A1PendingUtilityA1

Elimination of alum yellowing of aspen thermomechanical pulp through pulp washing

49
Assignee: INT PAPER COPriority: Aug 31, 2002Filed: Jan 12, 2006Published: Jul 13, 2006
Est. expiryAug 31, 2022(expired)· nominal 20-yr term from priority
Inventors:Robin KilgannonRobert J. KaneEileen JoyAnik Dewan
D21C 9/02D21C 9/1031
49
PatentIndex Score
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Cited by
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References
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Claims

Abstract

This invention relates to an improved process for manufacturing bleached thermomechanical aspen pulp having reduced yellow after treatment with aluminum based chemicals such as alum which are used in paper making processes. In this improved process the pulp is washed prior to, after or between the bleaching stages or a combination of the foregoing.

Claims

exact text as granted — not AI-modified
1 - 23 . (canceled)  
   
   
       24 . Pulp comprising aspen pulp made by a process that comprises 
 (a) a thermomechanical refining stage wherein aspen wood chips are thermomechanically refined to form thermomechanical refined aspen wood pulp; (b) a bleaching stage wherein said thermomechanical refined aspen wood pulp is bleached in one or more bleaching stages to form a first bleached thermomechanical refined aspen wood pulp; and (c) a washing stage subsequent to said thermomechanical refining stage wherein said thermomechanical refined aspen wood pulp, bleached thermomechanical refined aspen wood or a combination thereof is washed at least once with an aqueous liquid composition.    
   
   
       25 . The pulp according to  claim 24 , wherein said aspen pulp has a higher ISO brightness than an aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       26 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is at least about 1.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       27 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is at least about 1.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       28 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is at least about 2.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       29 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is at least about 3.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       30 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is from about 1.0 to about 4.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       31 . The pulp according to  claim 24 , wherein the aspen pulp has an ISO brightness that is from about 2.0 to about 4.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       32 . The pulp according to  claim 24 , wherein the aspen pulp is derived from aspen.  
   
   
       33 . The pulp according to  claim 24 , wherein said aspen pulp is washed prior to bleaching.  
   
   
       34 . The pulp according to  claim 33 , wherein said aspen pulp has a higher ISO brightness than an aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       35 . The pulp according to  claim 33 , wherein the aspen pulp has an ISO brightness that is at least about 1.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       36 . The pulp according to  claim 33 , wherein the aspen pulp has an ISO brightness that is from about 1.0 to about 4.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       37 . The pulp according to  claim 33 , wherein the aspen pulp is derived from aspen.  
   
   
       38 . The pulp according to  claim 24 , wherein said aspen pulp is washed after bleaching.  
   
   
       39 . The pulp according to  claim 38 , wherein said aspen pulp has a higher ISO brightness than an aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       40 . The pulp according to  claim 38 , wherein the aspen pulp has an ISO brightness that is at least about 1.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       41 . The pulp according to  claim 38 , wherein the aspen pulp has an ISO brightness that is from about 1.0 to about 4.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       42 . The pulp according to  claim 38 , wherein the aspen pulp is derived from aspen.  
   
   
       43 . The pulp according to  claim 24 , wherein said aspen pulp is made by a process further comprising a plurality of bleaching stages.  
   
   
       44 . The pulp according to  claim 43 , wherein said aspen pulp is washed before at least one bleaching stage.  
   
   
       45 . The pulp according to  claim 44 , wherein said aspen pulp has a higher ISO brightness than an aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       46 . The pulp according to  claim 44 , wherein the aspen pulp has an ISO brightness that is at least about 1.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       47 . The pulp according to  claim 44 , wherein the aspen pulp has an ISO brightness that is from about 1.0 to about 4.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       48 . The pulp according to  claim 44 , wherein the aspen pulp is derived from aspen.  
   
   
       49 . The pulp according to  claim 43 , wherein said aspen pulp is washed after at least one bleaching stage.  
   
   
       50 . The pulp according to  claim 49 , wherein said aspen pulp has a higher ISO brightness than an aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       51 . The pulp according to  claim 49 , wherein the aspen pulp has an ISO brightness that is at least about 1.0 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       52 . The pulp according to  claim 49 , wherein the aspen pulp has an ISO brightness that is from about 1.0 to about 4.5 ISO brightness units greater than the ISO brightness of aspen wood pulp formed by the same or substantially the same process in the absence of said (c) washing stage.  
   
   
       53 . The pulp according to  claim 49 , wherein the aspen pulp is derived from aspen.

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