Coated paper product and the method for producing the same

Abstract

The present invention relates to a coated paper product and the method for producing the same. High levels of an organic pigment, an inorganic pigment, relatively high levels of a binder, as well as, water are combined to form a coating composition which is applied to a low weight paper web. Then, the coated paper web is dried and calendered at relatively low calender intensity. A high bulk low weight or ultra-low weight coated paper product results which exhibits optical and printing properties comparable to its heavier counterparts.

1 . A coated paper product comprising: 
 a 16 to 36 lbs per ream uncoated paper web comprising ground wood-containing pulp; 
 wherein the paper web is coated on both sides with an aqueous coating composition comprising:  
 0 to 45 parts inorganic pigment per 100 parts of total pigment on a dry basis,  
 55 to 100 parts void-containing polymeric pigment particles per 100 parts of total pigment on a dry basis wherein said void containing particles have a diameter from 0.2 to 5 μm and a void volume of 20-80%,  
 10 to 50 parts of starch-based or protein-based polymeric binder per 100 parts of total pigment on a dry basis, wherein  
   the dried and calendered coated paper product has 1 to 3 lbs per ream per side of the dried coating composition and has a weight of 18 to 40 lbs per ream, an opacity of not greater than about 90, a gloss from 40 to 85, and a brightness from 70 to 83.    
   
   
       2 . The coated paper product of  claim 1  further comprising 5 to 25 parts of synthetic binder per 100 parts of total pigment on a dry basis.  
   
   
       3 . The coated paper product of  claim 2  wherein the void-containing pigment particles comprise a particle size of 0.3-2.0 μm.  
   
   
       4 . The coated paper product of  claim 3  wherein said void-containing pigment particles comprise a void volume of 40-70%.  
   
   
       5 . The coated paper product of  claim 4  wherein the paper product has a weight of 24-34 lbs per ream after coating with the composition.  
   
   
       6 . The coated paper product of  claim 5  wherein the opacity is 85-90.  
   
   
       7 . The coated paper product of  claim 6  wherein the gloss is 50-55.  
   
   
       8 . A method of producing a coated paper product comprising the steps of: 
 coating a ground wood containing paper web having an uncoated weight of 16 to 36 pounds per ream on at least one side of the ground wood containing paper web with a coating composition comprising: 
 0 to 45 parts inorganic pigment per 100 parts of total pigment on a dry basis,  
 55 to 100 parts void-containing polymeric pigment particles per 100 parts of total pigment on a dry basis wherein said void containing particles have a diameter from 0.2 to about 5 μm and a void volume of 20-80%,  
 10 to 50 parts of starch-based or protein-based polymeric binder per 100 parts of total pigment on a dry basis, and  
 water in an amount greater than 60% of the total aqueous composition,  
   drying the coating composition on the paper product such that 1 to 3 lbs per ream per side of the dried coating composition remains on the dried coated paper product providing a dried coated paper product having a weight of 18 to 40 lbs per ream, an opacity of not greater than about 90, a gloss from 40 to 85, and a brightness from 70 to 83, and;    passing the dried coated paper product through a calender device, wherein the calender device comprises at least two rolls and at least one nip.    
   
   
       9 . The method of  claim 8 , wherein the coating composition is applied with a short dwell coater at a weight of 1.0 pound per ream per side to 2.5 pounds per ream per side, based on the total dry weight of the coating composition.  
   
   
       10 . The method of  claim 8 , wherein the coating composition is applied with a jet coater at a weight of 1.0 pound per ream per side to 2.5 pounds per ream per side, based on the total dry weight of the coating composition.  
   
   
       11 . The method of clam  8  wherein the paper product is calendered by a soft-nip calender device comprising rolls which are arranged in series wherein the device is heated to 70-200° C.  
   
   
       12 . The method of  claim 8  wherein the paper product is calendered on an off-line super-calender device comprising about 3-5 nips wherein the device is heated to 50-150° C.