Microwave pretreatment of logs for use in making paper and other wood products

Abstract

A method of producing pulp for use in making paper products using microwave radiation to pretreat the source of pulp prior to further processing. Practicing the method of the invention results in substantial energy savings while decreasing environmental impact and improving paper qualities.

1 . A method of producing pulp for use in making paper products, wherein the pulp source comprises wood logs, further comprising the steps of: 
 treating the wood logs with microwave radiation;    chipping the logs to provide wood chips; and    mechanically processing the wood chips to provide pulp.    
   
   
       2 . The method of  claim 1  further comprising the step of fiber loading the mechanically processed pulp.  
   
   
       3 . The method of  claim 1 , wherein the logs comprise a hardwood species.  
   
   
       4 . The method of  claim 3  wherein the logs comprise at least one of an aspen species, a eucalyptus species and an oak species.  
   
   
       5 . The method of  claim 1 , wherein the logs comprise a softwood species.  
   
   
       6 . The method of  claim 5 , wherein the logs comprise at least one of a spruce species and a pine species.  
   
   
       7 . The method of  claim 1 , wherein mechanically processing comprises an RMP process, a TMP process or a CTMP process.  
   
   
       8 . The method of  claim 1 , wherein mechanically processing comprises a TMP process.  
   
   
       9 . A paper produced according to the method of  claim 1 .  
   
   
       10 . The paper of  claim 9 , wherein the paper demonstrates improved strength properties over a paper produced according to a method not including treating logs with microwave radiation.  
   
   
       11 . The paper of  claim 9  wherein the paper demonstrates at least about a 10% increase in measurements of tear index, burst index and tensile index.  
   
   
       12 . A method of producing pulp for use in making paper products, the method comprising the steps of: 
 treating wood logs with microwave radiation;    chipping the logs to provide wood chips;    inoculating the wood chips with a fungus; and    mechanically processing the inoculated wood chips to provide pulp.    
   
   
       13 . The method of  claim 12 , wherein the fungus comprises a white rot fungus.  
   
   
       14 . The method of  claim 13 , wherein the fungus comprises  Ceriporiopsis subvermispora, Hyphodontia setulos, Phlebia subserialis, Phlebia brevispora, Phlebia tremellosa  or  Phanerochaete chrysosporium.    
   
   
       15 . The method of  claim 12 , wherein the fungus comprises a white or colorless species of  Ophiostoma piliferum.    
   
   
       16 . A method of producing pulp for use in making paper products, the method comprising the steps of: 
 treating wood logs with microwave radiation;    chipping the logs to provide wood chips;    treating the wood chips with enzymes; and    mechanically processing the enzyme-treated wood chips to provide pulp.    
   
   
       17 . The method of  claim 16  wherein the enzymes comprise at least one of lignin-degrading enzymes, xylanases, pectinases, lipases and cellulases.  
   
   
       18 . A method of reducing energy input requirements during wood pulping comprising the steps of: 
 treating logs with microwave radiation;    chipping the logs to provide wood chips; and    mechanically pulping the wood chips to provide pulp;    wherein the energy input requirement is reduced at least about 8% over a method not including the step of treating logs with microwave radiation.    
   
   
       19 . The method of  claim 18  wherein the energy input requirement is reduced at least about 8% to about 15% over a method not including the step of treating logs with microwave radiation.  
   
   
       20 . The method of  claim 1  wherein treating wood logs with microwave radiation comprises microwaving the logs with a 915 MHz microwave generator for 5 minutes at 50 kW.  
   
   
       21 . The method of  claim 20  wherein treating the logs with microwave radiation results in a temperature of 130° C. inside the logs.  
   
   
       22 . The method of  claim 11 , wherein the burst index is increased at least about 30%, the tear index is increased at least about 15% and the tensile index is increased at least about 20%.  
   
   
       23 . A method of reducing pitch in a wood log comprising the step of treating a wood log with microwave radiation.  
   
   
       24 . The method of  claim 23  wherein the wood log comprises a softwood species.  
   
   
       25 . The method of  claim 23  wherein the wood log comprises a hardwood species.