High bulk paper

Abstract

A method and apparatus are disclosed for making a high bulk, coated paper of a unique structure with the coating forming a lower portion of the total caliper and the paper base forming a higher portion of the total caliper than conventionally made coated paper of the same weight. The process includes the step of using furnish with a high percentage of mechanical pulp, applying that furnish to papermachine wires, preferably with a gap former, coating the paper with a coating containing a plastic pigment, preferably of 4 or more parts per 100 parts of coating pigment, and calendering the coated paper at a nip loading less than conventional supercalendering nip loading. Preferably, the finished coated paper will have a 75° TAPPI gloss of 40 or above. The method and apparatus can be used to make lightweight or other weights of coated paper.

What is claimed is:  
     
         1 . A papermaking apparatus for making a lightweight high bulk coated paper web from a waterborne furnish containing at least 50% mechanical pulp, comprising gap former section means for extruding the furnish and forming the paper web from said furnish, press section means for removing water from the formed paper web, dryer means for drying the paper web to less than 10% moisture content, coater means for applying a coating to the paper web, and means for calendering the coated paper web to a finished caliper greater than the caliper of conventional paper of the same weight and a 75° TAPPI gloss of 40 or greater, whereby the coated paper web formed is of high bulk in relation to its light weight with a good gloss.  
     
     
         2 . A papermaking apparatus as in  claim 1 , wherein said press section means further comprises extended nip press means for densifying the paper web less than would conventional press means.  
     
     
         3 . A papermaking apparatus as in  claim 1 , wherein said calender means comprises hot-soft calender means for hot-soft calendering the coated paper web.  
     
     
         4 . A papermaking apparatus as in  claim 1 , wherein said calender means comprises supercalender means for supercalendering the coated paper web at a supercalender nip loading that is substantially less than conventional supercalender nip loading.  
     
     
         5 . A papermaking apparatus as in  claim 1 , wherein said coater means comprises a blade coater for applying light coat weight to the paper web.  
     
     
         6 . A papermaking apparatus as in  claim 5 , wherein said blade coater is a single blade coater.  
     
     
         7 . A papermaking apparatus as in  claim 5 , wherein said blade coater is a double blade coater.  
     
     
         8 . A papermaking apparatus as in  claim 6 , wherein said blade coater is a short dwell time applicator.  
     
     
         9 . A papermaking apparatus as in  claim 6 , wherein said blade coater is a fountain coater.  
     
     
         10 . A papermalling apparatus as in  claim 5 , wherein said coater includes a first blade coater with its own blade and a second blade spaced downstream from said first blade coater.  
     
     
         11 . A papermaking apparatus as in  claim 10 , wherein said first blade coater is a short dwell time applicator.  
     
     
         12 . A papermaking apparatus as in  claim 5 , further comprising a second blade coater, the first blade coater operating on one side of the paper web and the second blade coater operating on the other side of the paper web.  
     
     
         13 . A process for making lightweight high bulk coated paper comprising the steps of: 
 providing a waterborne furnish comprising at least 50% mechanical pulp;    forming a paper web by extruding the furnish onto wire sides of a papermaking apparatus with a gap former;    pressing excess water from the paper web to provide a paper web of a caliper that is substantially greater than that of a conventional paper web of the same total weight;    drying the paper web to a moisture content of less than 10%;    coating the paper web with a coating weight that is substantially less than that applied to conventional coated paper of the same total weight; and    calendering the coated paper web to a caliper greater than the caliper of conventional coated paper of the same total weight, and to a 75° TAPPI gloss of 40 or greater;    whereby a lightweight coated paper is produced with a 75° TAPPI gloss of at least 40 and with a greater paper base caliper and lesser coating caliper than for conventional coated paper of the same total weight.    
     
     
         14 . A process as in  claim 13 , wherein said pressing step includes the step of densifying the paper web with an extended nip press.  
     
     
         15 . A process as in  claim 13 , wherein said calendering step includes the step of hot-soft calendering the coated paper web.  
     
     
         16 . A process as in  claim 13 , wherein said calendering step includes the step of supercalendering the paper web at a supercalender nip loading that is substantially less than nip loading used in conventional supercalendering of conventional coated paper of the same weight.  
     
     
         17 . A process as in  claim 16 , wherein said supercalendering step is carried out at a nip loading of about two-thirds of that for conventional supercalendering of conventional coated paper of the same weight.  
     
     
         18 . A process as in  claim 13 , wherein the coated paper produced has about 10 to 20% greater caliper than a conventional coated paper of a same weight.  
     
     
         19 . A process as in  claim 13 , wherein said step of forming the paper web includes forming a base having a weight of about 24 to 34 pounds per ream.  
     
     
         20 . A process as in  claim 13 , wherein said step of coating the paper web includes applying a coat weight of 3 or less pounds per ream on a side of the paper web.  
     
     
         21 . A process as in  claim 13 , wherein said forming step includes forming a base having a caliper of at least about 88% of the total caliper of the finished coated paper.  
     
     
         22 . A process as in  claim 21 , wherein said coating step includes applying to a side of the web coating that is no more than about 6% of the total caliper of the finished coated paper.  
     
     
         23 . A process as in  claim 21 , wherein said coating step includes applying to each of the two sides of the web coating that in total is no more than about 12% of the total caliper of the finished coated paper.  
     
     
         24 . A process as in  claim 23 , wherein said coating step includes applying to the paper web a coating that is not in excess of about 12% of the total caliper of the finished coated paper.  
     
     
         25 . A process as in  claim 24 , wherein said coating step includes applying about one-half of the coating to each side of the paper web.  
     
     
         26 . A process as in  claim 24 , wherein said forming step provides the balance of the percentage of the total caliper of the finished coated paper.  
     
     
         27 . A process as in  claim 13 , wherein said coating step includes coating the paper web with a coating containing plastic pigment.  
     
     
         28 . A process as in  claim 27 , wherein said calendering step includes calendering the paper to a 75° TAPPI gloss of at least 40.  
     
     
         29 . A process as in  claim 13 , where said step of coating the paper web includes applying coating having a weight of about 4 to 6 pounds per ream.  
     
     
         30 . A process as in  claim 13 , wherein said steps of forming and coating include forming a base that comprises about 75 to 85% by weight of the total weight of the coated paper and applying a coating to the base that comprises about 25 to 15% by weight of the total weight of the coated paper.  
     
     
         31 . A process as in  claim 30 , wherein said forming and coating steps include forming a base that comprises about 80 to 85% by weight, and applying a coating to the base that comprises about 20 to 15% by weight, of the total weight of the coated paper.  
     
     
         32 . A lightweight high bulk coated paper with a 75° TAPPI gloss of at least 40, comprising a paper base of a weight of 24 to 34 pounds per ream, a coating containing a plastic pigment on each side of said base, said coating being of a weight of no more than 3 pounds per ream per side, said base having a caliper of at least about 88% of the total caliper of said coated paper and said coating providing substantially the remainder of said caliper of said coated paper, said coated paper having a 75° TAPPI gloss of at least 40.  
     
     
         33 . A paper as in  claim 32 , wherein said plastic pigment of said coating is at least 4 parts per 100 parts pigment of said coating.  
     
     
         34 . A paper as in  claim 32 , wherein said base comprises about 75 to 85% by weight, and said coating comprises about 25 to 15% by weight, of the total weight of said coated paper.  
     
     
         35 . A paper as in  claim 32 , wherein said coating weight on at least one side of said web comprises about 1.5 to 3 pounds per ream.  
     
     
         36 . A paper as in  claim 32 , wherein said coating is applied in substantially equal weights on each side of said base.  
     
     
         37 . A paper as in  claim 32 , wherein base comprises at least 55% mechanical pulp.  
     
     
         38 . A paper as in  claim 32 , wherein said base is a gap formed base.  
     
     
         39 . A paper as in  claim 32 , wherein said base is an extended nip pressed base.  
     
     
         40 . A paper as in  claim 32 , wherein said coated paper is a supercalendered coated paper having a 75° TAPPI gloss of at least 40.  
     
     
         41 . A paper as in  claim 32 , wherein said coated paper is a coated paper that has been supercalendered at about two-thirds conventional supercalendering nip loads.  
     
     
         42 . A paper as in  claim 32 , wherein said coated paper is a hot-soft calendered coated paper having a 75° TAPPI gloss of at least 40.  
     
     
         43 . A paper as in  claim 32 , wherein said coated paper has a 75° TAPPI gloss of at least 45.  
     
     
         44 . A paper as in  claim 32 , wherein said coated paper is a coated paper that has been calendered to a 75° TAPPI gloss of at least 45.  
     
     
         45 . A papermaking apparatus for making an ultralightweight high bulk coated paper web from a waterborne furnish containing at least 50% mechanical pulp, comprising gap former section means for extruding the furnish and forming the paper web from said furnish, press section means for removing water from the formed paper web, dryer means for drying the paper web to less than 10% moisture content, coater means for applying a coating to the paper web, and means for calendering the coated paper web to a finished caliper greater than the caliper of conventional paper of the same weight and to a 75° TAPPI gloss of 35, whereby the coated paper web formed is of high bulk in relation to its ultralightweight with a good gloss for its weight.  
     
     
         46 . A papermaking apparatus as in  claim 45 , wherein said press section means further comprises wide nip press means for densifying the paper web less than would conventional press means.  
     
     
         47 . A papermaking apparatus as in  claim 45 , wherein said calender means comprises hot-soft calender means for hot-soft calendering the coated paper web.  
     
     
         48 . A papermaking apparatus as in  claim 45 , wherein said calender means comprises supercalender means for supercalendering the coated paper web at a supercalender nip loading that is substantially less than conventional supercalender nip loading.  
     
     
         49 . A papermaking apparatus as in  claim 45 , wherein said coater means comprises a blade coater for applying light coat weight to the paper web.  
     
     
         50 . A papermaking apparatus as in  claim 49 , wherein said blade coater is a single blade coater.  
     
     
         51 . A papermaking apparatus as in  claim 49 , wherein said blade coater is a double blade coater.  
     
     
         52 . A papermaking apparatus as in  claim 50 , wherein said blade coater is a short dwell time applicator.  
     
     
         53 . A papermaking apparatus as in  claim 50 , wherein said blade coater is a fountain coater.  
     
     
         54 . A papermaking apparatus as in  claim 49 , wherein said coater includes a first blade coater with its own blade and a second blade spaced downstream from said first blade coater.  
     
     
         55 . A papermaking apparatus as in  claim 54 , wherein said first blade coater is a short dwell time applicator.  
     
     
         56 . A papermaking apparatus as in  claim 49 , further comprising a second blade coater, the first blade coater operating on one side of the paper web and the second blade coater operating on the other side of the paper web.  
     
     
         57 . A process for making ultralightweight high bulk coated paper comprising the steps of: 
 providing a waterborne furnish comprising at least 50% mechanical pulp;    forming a paper web by extruding the furnish onto wire sides of a papermaking apparatus with a gap former;    pressing excess water from the paper web to provide a paper web of a caliper that is substantially greater than that of a conventional paper web of the same total weight;    drying the paper web to a moisture content of less than 10%;    coating the paper web with a coating weight that is substantially less than that applied to conventional coated paper of the same total weight; and    calendering the coated paper web to a caliper greater than the caliper of conventional coated paper of the same total weight, and to a 75° TAPPI gloss of at least 35.    whereby an ultralightweight coated paper is produced with a 75° TAPPI gloss of at least 35 and with a greater paper base caliper and lesser coating caliper than for conventional coated paper of the same total weight.    
     
     
         58 . A process as in  claim 57 , wherein said pressing step includes the step of densifying the paper web with an extended nip press.  
     
     
         59 . A process as in  claim 57 , wherein said calendering step includes the step of hot-soft calendering the coated paper web.  
     
     
         60 . A process as in  claim 57 , wherein said calendering step includes the step of supercalendering the paper web at a supercalender nip loading that is substantially less than nip loading used in conventional supercalendering of conventional coated paper of the same weight.  
     
     
         61 . A process as in  claim 60 , wherein said supercalendering step is carried out at a nip loading of about two-thirds of that for conventional supercalendering of conventional coated paper of the same weight.  
     
     
         62 . A process as in  claim 57 , wherein the coated paper produced has about 10 to 20% greater caliper than a conventional coated paper of a same weight.  
     
     
         63 . A process as in  claim 57 , wherein said step of forming the paper web includes forming a base having a weight of about 18 to less than 24 pounds per ream.  
     
     
         64 . A process as in  claim 57 , wherein said step of coating the paper web includes applying a coat weight of 2 or less pounds per ream on a side of the paper web.  
     
     
         65 . A process as in  claim 57 , wherein said forming step includes forming a base having a caliper of at least about 88% of the total caliper of the finished coated paper.  
     
     
         66 . A process as in  claim 65 , wherein said coating step includes applying to a side of the web coating that is no more than about 6% of the total caliper of the finished coated paper.  
     
     
         67 . A process as in  claim 65 , wherein said coating step includes applying to each of the two sides of the web coating that in total is no more than about 12% of the total caliper of the finished coated paper.  
     
     
         68 . A process as in  claim 57 , wherein said coating step includes applying to the paper web a coating that is not in excess of about 12% of the total caliper of the finished coated paper.  
     
     
         69 . A process as in  claim 68 , wherein said coating step includes applying about one-half of the coating to each side of the paper web.  
     
     
         70 . A process as in  claim 68 , wherein said forming step provides the balance of the percentage of the total caliper of the finished coated paper.  
     
     
         71 . A process as in  claim 57 , wherein said coating step includes coating the paper web with a coating containing plastic pigment.  
     
     
         72 . A process as in  claim 61 , wherein said calendering step includes calendering the paper to a 75° TAPPI gloss of at least 35.  
     
     
         73 . A process as in  claim 57 , where said step of coating the paper web includes applying coating having a weight of about 18 to less than 24 pounds per ream.  
     
     
         74 . A process as in  claim 57 , wherein said steps of forming and coating include forming a base that comprises about 75 to 85% by weight of the total weight of the coated paper and applying a coating to the base that comprises about 25 to 15% by weight of the total weight of the coated paper.  
     
     
         75 . A process as in  claim 57 , wherein said forming and coating steps include forming a base that comprises about 80 to 85% by weight, and applying a coating to the base that comprises about 20 to 15% by weight, of the total weight of the coated paper.  
     
     
         76 . An ultralightweight high bulk coated paper with a 75° TAPPI gloss of at least 35, comprising a paper base of a weight of 18 to less than 24 pounds per ream, a coating containing a plastic pigment on each side of said base, said coating being of a weight of no more than 2 pounds per ream per side, said base having a caliper of at least about 88% of the total caliper of said coated paper and said coating providing substantially the remainder of said caliper of said coated paper, said coated paper having a 75° TAPPI gloss of at least 35.  
     
     
         77 . A paper as in  claim 76 , wherein said plastic pigment of said coating is at least 4 parts per 100 parts pigment of said coating.  
     
     
         78 . A paper as in  claim 76 , wherein said base comprises about 75 to 85% by weight, and said coating comprises about 25 to 15% by weight, of the total weight of said coated paper.  
     
     
         79 . A paper as in  claim 76 , wherein said coating weight on at least one side of said web comprises about 1.0 to 2.0 pounds per ream.  
     
     
         80 . A paper as in  claim 76 , wherein said coating is applied in substantially equal weights on each side of said base.  
     
     
         81 . A paper as in  claim 76 , wherein base comprises at least 55% mechanical pulp.  
     
     
         82 . A paper as in  claim 76 , wherein said base is a gap formed base.  
     
     
         83 . A paper as in  claim 76 , wherein said coater paper is a supercalendered coated paper having a 75° TAPPI gloss of at least 35.  
     
     
         84 . A paper as in  claim 76 , wherein said coated paper is a coated paper that has been supercalendered at about two-thirds conventional supercalendering nip loads.  
     
     
         85 . A paper as in  claim 76 , wherein said coated paper is a hot-soft calendered coated paper having a 75° TAPPI gloss of at least 35.  
     
     
         86 . A paper as in  claim 76 , wherein said coated paper has a 75° TAPPI gloss of at least 40.  
     
     
         87 . A paper as in  claim 76 , wherein said coated paper is a coated paper that has been calendered to a 75° TAPPI gloss of at least 40.  
     
     
         88 . A papermaking apparatus for making high bulk coated paper web from a waterborne furnish containing at least 50% mechanical pulp, comprising double wire former section means for extruding the furnish and forming the paper web from said furnish, extended nip press section means for removing water from the formed paper web, dryer means for drying the paper web to less than 10% moisture content, coater means for applying a coating to the paper web, and means for hot-soft calendering the coated paper web to a finished caliper greater than the caliper of conventional paper of the same weight and to a 75° TAPPI gloss of 40 or greater, whereby the coated paper web formed is of high bulk in relation to its light weight with a good gloss.  
     
     
         89 . A papermaking apparatus as in  claim 88 , wherein said coater means comprises a blade coater for applying light coat weight to the paper web.  
     
     
         90 . A papermaking apparatus as in  claim 89 , wherein said blade coater is a single blade coater.  
     
     
         91 . A papermaking apparatus as in  claim 89 , wherein said blade coater is a double blade coater.  
     
     
         92 . A papermaking apparatus as in  claim 90 , wherein said blade coater is a short dwell time applicator.  
     
     
         93 . A papermaking apparatus as in  claim 90 , wherein said blade coater is a fountain coater.  
     
     
         94 . A papermaking apparatus as in  claim 89 , wherein said coater includes a first blade coater with its own blade and a second blade spaced downstream from said first blade coater.  
     
     
         95 . A papermaking apparatus as in  claim 94 , wherein said first blade coater is a short dwell time applicator.  
     
     
         96 . A papermaking apparatus as in  claim 89 , further comprising a second blade coater, the first blade coater operating on one side of the paper web and the second blade coater operating on the other side of the paper web.  
     
     
         97 . A process for making high bulk coated paper comprising the steps of: 
 providing a waterborne furnish comprising at least 50% mechanical pulp;    forming a paper web by extruding the furnish onto wire sides of a papermaking apparatus with a double wire former;    pressing excess water from the paper web with an extended nip press to provide a paper web of a caliper that is substantially greater than that of a conventional paper web of the same total weight;    drying the paper web to a moisture content of less than 10%;    coating the paper web with a coating weight that is substantially less than that applied to conventional coated paper of the same total weight; and    hot-soft calendering the coated paper web to a caliper greater than the caliper of conventional coated paper of the same total weight, and to a 75° TAPPI gloss of at least 40;    whereby a coated paper is produced with a 75° TAPPI gloss of at least 40 and with a greater paper base caliper and lesser coating caliper than for conventional coated paper of the same total weight.    
     
     
         98 . A process as in  claim 97 , wherein the coated paper produced has about 10 to 20% greater caliper than a conventional coated paper of a same weight.  
     
     
         99 . A process as in  claim 97 , wherein said step of forming the paper web includes forming a base having a weight of about 18 to 40 pounds per ream.  
     
     
         100 . A process as in  claim 97 , wherein said step of coating the paper web includes applying a coat weight of 3 or less pounds per ream on a side of the paper web.  
     
     
         101 . A process as in  claim 97 , wherein said forming step includes forming a base having a caliper of at least about 88% of the total caliper of the finished coated paper.  
     
     
         102 . A process as in  claim 101 , wherein said coating step includes applying to a side of the web coating that is no more than about 6% of the total caliper of the finished coated paper.  
     
     
         103 . A process as in  claim 97 , wherein said coating step includes applying about one-half of the coating to each side of the paper web.  
     
     
         104 . A process as in  claim 97 , wherein said coating step includes coating the paper web with a coating containing plastic pigment.  
     
     
         105 . A process as in  claim 97 , where said step of forming the paper web includes forming a base having a weight of about 18 to 34 pounds per ream.  
     
     
         106 . A process as in  claim 97 , wherein said steps of forming and coating include forming a base that comprises about 75 to 85% by weight of the total weight of the coated paper and applying a coating to the base that comprises about 25 to 15% by weight of the total weight of the coated paper.  
     
     
         107 . A process as in  claim 97 , wherein said forming and coating steps include forming a base that comprises about 80 to 85% by weight, and applying a coating to the base that comprises about 20 to 15% by weight, of the total weight of the coated paper.  
     
     
         108 . A high bulk coated paper with a 75° TAPPI gloss of at least 40, comprising a paper base of a weight of 18 to 34 pounds per ream, a coating containing a plastic pigment on each side of said base, said coating being of a weight of no more than 3 pounds per ream per side, said base having a caliper of at least about 88% of the total caliper of said coated paper and said coating providing substantially the remainder of said caliper of said coated paper, said coated paper having a 75° TAPPI gloss of at least 40.  
     
     
         109 . A paper as in  claim 108 , wherein said plastic pigment of said coating is at least 4 parts per 100 parts pigment of said coating.  
     
     
         110 . A paper as in  claim 108 , wherein said base comprises about 75 to 85% by weight, and said coating comprises about 25 to 15% by weight, of the total weight of said finished coated paper.  
     
     
         111 . A paper as in  claim 108 , wherein said coating weight on at least one side of said web comprises about 1.0 to 3 pounds per ream.  
     
     
         112 . A paper as in  claim 111 , wherein said coating is applied in substantially equal weights on each side of said base.  
     
     
         113 . A paper as in  claim 108 , wherein base comprises at least 55% mechanical pulp.  
     
     
         114 . A paper as in  claim 108 , wherein said coated paper has a 75° TAPPI gloss of at least 40.  
     
     
         115 . A paper as in  claim 108 , wherein said coated paper is a coated paper that has been calendered to a 75° TAPPI gloss of at least 45.