Cellulose pulp having increased hemicellulose content

Abstract

Bleached, Kraft chemical pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In one embodiment, the pulp has a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test. In another aspect, a method for making wood cellulose pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In the method, a lignocellulosic material is pulped in caustic sulfide to provide a first brownstock, which is treated with oxygen to provide a second brownstock, which is then bleached to provide the pulp product.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
         1 . A bleached, chemical pulp having a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test (TAPPI T-235 CM-00).  
     
     
         2 . The pulp of  claim 1 , wherein the digester pulp has a kappa number in the range from about 20 to about 65.  
     
     
         3 . The pulp of  claim 1 , wherein the pulp has a brightness in the range from about 75 to about 95.  
     
     
         4 . The pulp of  claim 1 , wherein the pulp has an initial tensile strength in the range from about 4.5 km to about 5.5 km.  
     
     
         5 . A tissue product, comprising a bleached, chemical pulp having a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test (TAPPI T-235 CM-00).  
     
     
         6 . The tissue product of  claim 5 , wherein the pulp is present in the tissue in an amount from about 10 to about 40 percent by weight based on the total weight of the tissue.  
     
     
         7 . The tissue product of  claim 5  further comprising a second pulp.  
     
     
         8 . The tissue product of  claim 7 , wherein the second pulp is at least one of a northern bleached Kraft pulp, southern bleached Kraft pulp, or a chemi-thermomechanical pulp.  
     
     
         9 . A towel product, comprising a bleached, chemical pulp having a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test (TAPPI T-235 CM-00).  
     
     
         10 . The towel product of  claim 9 , wherein the pulp is present in the towel in an amount from about 30 to about 75 percent by weight based on the total weight of the tissue.  
     
     
         11 . The towel product of  claim 9  further comprising a second pulp.  
     
     
         12 . The towel product of  claim 11 , wherein the second pulp is at least one of a northern bleached Kraft pulp, southern bleached Kraft pulp, or a chemi-thermomechanical pulp.