Insulating paperboard

Abstract

An insulating paperboard contains at least one layer of cellulose fibers. The one layer is at least partially composed of processed cellulosic fibers. The paperboard provides sufficient insulation to provide a hot water ΔT across the paperboard of at least 0.8° C. per 0.1 mm of caliper. A hot cup may be produced from the insulating paperboard.

1 . An insulating paperboard comprising: 
 at least one layer of cellulose fibers, at least some of the cellulose fibers comprising processed cellulosic fibers, said processed cellulosic fibers being present in an amount from 25% to 70 percent of said at least one layer, said paperboard being sufficiently insulating to provide a hot water ΔT across said paperboard of at least 0.8° C. per 0.1 mm of caliper.    
   
   
       2 . The processed fibers of  claim 1  wherein the fibers are selected from the group consisting of chemically processed fibers, mercerized fibers, mechanically processed fibers, chemimechanically processed fibers, jet dried fibers, flash dried fibers and mixtures thereof.  
   
   
       3 . The fibers of  claim 2  wherein the processed fibers are mercerized fibers.  
   
   
       4 . The fibers of  claim 2  wherein the processed fibers are CTMP fibers.  
   
   
       5 . The fibers of  claim 2  wherein the processed fibers are BCTMP fibers.  
   
   
       6 . The fibers of  claim 2  wherein the processed fibers are TMP fibers.  
   
   
       7 . The fibers of  claim 2  wherein the processed fibers are jet dried fibers.  
   
   
       8 . The fibers of  claim 2  wherein the processed fibers are flash dried fibers.  
   
   
       9 . The insulating paperboard of  claim 1 , wherein said paperboard has a density of less than 0.5 g/cc.  
   
   
       10 . The insulating paperboard of  claim 2 , wherein said paperboard has a basis weight of from 250 gsm to 400 gsm.  
   
   
       11 . The insulating paperboard of  claim 2 , wherein said paperboard has a basis weight greater than or equal to 250 gsm.  
   
   
       12 . The insulating paperboard of  claim 3 , wherein the caliper of said paperboard is greater than or equal to 0.5 mm.  
   
   
       13 . The insulating paperboard of  claim 1 , wherein said paperboard has a hot water ΔT of at least 5.3° C. at a caliper of 0.6 mm and a hot water ΔT of 10.8° C. at a caliper of 1.25 mm, said hot water ΔT being a substantially linear progression relative to caliper in the temperature range from below 4° C. to above 10.3° C.  
   
   
       14 . The insulating paperboard of  claim 6 , wherein said linear progression extends from a ΔT of 4° C. to a ΔT of 10.3° C.  
   
   
       15 . The insulating paperboard of  claim 1 , wherein said paperboard is at least a two-ply board, said at least one ply containing said processed cellulosic fibers.