Smooth base stock composed of nonstandard fibers

Abstract

A smooth base stock useful in various applications, but particularly useful in high quality imaging, comprising nonstandard fibers is disclosed. The base stock fibers have a fiber length weighted average of greater than about 0.9 mm and the base stock has a roughness of less than about 2.0 micron Ra.

1 . A base stock comprising fibers wherein the fibers have a fiber length weighted average of greater than about 0.9 mm and wherein the base stock has a roughness of less than about 2.0 micron Ra.  
     
     
         2 . The base stock in accordance with  claim 1  wherein the base stock has a roughness of less than about 1.5 micron Ra.  
     
     
         3 . The base stock in accordance with  claim 2  wherein the base stock has a roughness of from about 1.2 micron Ra to about 1.5 micron Ra.  
     
     
         4 . The base stock in accordance with  claim 1  wherein the base stock comprises at least 50% non-standard fibers based on the total fiber content.  
     
     
         5 . The base stock in accordance with  claim 1  wherein the base stock comprises at least 50% fibers having a population of less than about 10×10 6  fibers/gram.  
     
     
         6 . The base stock in accordance with  claim 1  wherein the base stock is substantially free of filler pigments.  
     
     
         7 . A method for producing a base stock for use in forming a recording material comprising the steps of: 
 providing a fiber slurry comprising fibers having a length weighted average fiber length above about 1 mm,    forming a web of the fibers; and    subjecting the web to a smoothing operation to provide a base stock having a roughness of less than about 2.0 micron Ra.    
     
     
         8 . The method of  claim 7  wherein the base stock has a roughness of less than about 1.5 micron Ra.  
     
     
         9 . The method of  claim 8  wherein the base stock has a roughness of from about 1.2 micron Ra to about 1.5 micron Ra.  
     
     
         10 . The method of  claim 7  further comprising: 
 refining the fibers in the fiber slurry, wherein after the refinement treatment, the fibers have a length-weighted average fiber length of above about 0.9 mm.    
     
     
         11 . The method of  claim 10  wherein the fiber slurry is substantially free of filler pigments and the resulting base stock is substantially free of filler pigments.  
     
     
         12 . The method of  claim 7  further comprising: 
 coating the base stock on at least one side thereof with a pigment coating composition.    
     
     
         13 . The method of  claim 12  wherein said pigment coating composition comprises aragonite precipitated calcium carbonate, hollow sphere pigment and a binder.  
     
     
         14 . The method of  claim 13  wherein the binder comprises an acrylic binder selected from the group consisting of acrylic esters, modified acrylic esters, acrylic ester co-polymers, modified acrylic ester co-polymers and mixtures thereof.  
     
     
         15 . The method of  claim 14  wherein said pigment coating composition comprises from about 20 to about 30% acrylic binder, from about 15 to about 25% hollow sphere pigment and from about 40 to about 80% aragonite precipitated calcium carbonate based on dry weight of the pigment coating composition.  
     
     
         16 . A support material for an image forming system comprising: 
 a base paper comprising fibers wherein the fibers have a fiber length weighted average of greater than about 0.9 mm and wherein the base stock has a roughness of less than about 2.0 micron Ra.; and    an image forming or image receptive coating layer on at least one side of the paper wherein the image forming or image receptive coating is selected from the group consisting of a photosensitive emulsion, an ink jet receptive coating, a thermal dye recording layer and a pigment based ink receptive layer.    
     
     
         17 . The support material in accordance with  claim 16  wherein the support material further comprises a pigment coating comprising a pigment and a binder on at least one side of the paper thereby forming a pigment coated paper.  
     
     
         18 . The support material in accordance with  claim 17  wherein the support material further comprises a polymeric coating layer disposed between the pigment coating on the coated paper and the image forming or image receptive coating layer on one or both sides of the support material.  
     
     
         19 . The support material in accordance with  claim 18  wherein the polymeric coating layer comprises a polyolefin or polyester coating layer.  
     
     
         20 . The support material in accordance with  claim 18  wherein the pigment coating coat weight is from about 4 to about 15 lb/3300 ft 2 .  
     
     
         21 . The support material in accordance with  claim 20  wherein the pigment coating comprises from about 40 to about 80% aragonite precipitated calcium carbonate and from about 15 to 25% hollow sphere pigment by dry weight based on total pigment coating.  
     
     
         22 . The support material in accordance with  claim 21  wherein the pigment coating further comprises from about 20 to about 30% of an acrylic binder based on total pigment coating.  
     
     
         23 . The support material in accordance with  claim 20  wherein the pigment coating further comprises a binder present in the pigment coating composition at from about 8 to about 30% by weight of the dry pigment coating.  
     
     
         24 . The support material in accordance with  claim 21  wherein the pigment coating is substantially free of clay.  
     
     
         25 . The support material in accordance with  claim 18  wherein the base stock has a roughness of less than about 1.5 micron Ra.  
     
     
         26 . The support material in accordance with  claim 25  wherein the base stock has a roughness of from about 1.2 micron Ra to about 1.5 micron Ra.  
     
     
         27 . The support material in accordance with  claim 18  wherein the base stock comprises at least 50% non-standard fibers based on the total fiber content.  
     
     
         28 . The support material in accordance with  claim 18  wherein the base stock comprises at least 50% fibers having a population of less than about 10×10 6  fibers/gram.