Filler for the manufacture of base paper and method for the manufacture of base paper

Abstract

The invention relates to the use of precipitated calcium carbonates (PCC) as fillers for the manufacture of base paper together with mechanical hardwood pulp and chemical softwood pulp, and to a method for the manufacture of base paper, in which method pulp produced from hard woods, in particular from the wood of the genus Populus , and chemical softwood pulp are used together with a PCC filler. The use of precipitated calcium carbonate (PCC) for the manufacture of base paper together with mechanical hardwood pulp and chemical softwood pulp is characterized in that ≧20 wt-% of the fibres of the mechanical hardwood pulp is included in the fibre size fraction of <200 mesh and 10-40 wt-% of them is included in the fibre size fraction of {fraction (28/48)} mesh, the brightness of the mechanical hardwood pulp is ≧75, the particle size distribution of the precipitated calcium carbonate is 90%≦9 μm, 50%≦5 μm and 20%≦1.5 μm, and the basis weight of the base paper is 25-150 g/m 2 .

1 . The use of precipitated calcium carbonate (PCC) for the manufacture of thin base paper together with mechanical hardwood pulp and chemical softwood pulp, characterized in that ≧20 wt-% of the fibres of the mechanical hardwood pulp is included in the fibre size fraction of <200 mesh and 10-40 wt-% of them is included in the fibre size fraction of {fraction (28/48)} mesh, the brightness of the mechanical hardwood pulp is ≧75, the particle size distribution of the precipitated calcium carbonate is 90%≦9 μm, 50%≦5 μm and 20%≦1.5 μm, and the basis weight of the base paper is 25-150 g/m 2 .  
     
     
         2 . The use as claimed in  claim 1 , characterized in that the brightness of the mechanical hardwood pulp is ≧77, the particle size distribution of the precipitated calcium carbonate is 90%≦6.3 μm, 50%≦2.7 μm and 20%≦0.8 μm, and the basis weight of the base paper is 25-80 g/m 2 .  
     
     
         3 . The use as claimed in  claim 1  or  2 , characterized in that the mechanical hardwood pulp has been manufactured from aspen and/or from wood species of the genus  Populus.    
     
     
         4 . The use as claimed in  claim 1  or  2 , characterized in that the mechanical hardwood pulp contains CTMP pulp or pressure groundwood (PGW) or a combination of them, and the hardwood pulp has been manufactured from wood species of the genus  Populus  selected from the group of the following species:  P. tremula, P. tremuloides, P. balsamea, P. balsamifera, P. trichocarpa, P. heterophylla , aspen species crossbred from different mother aspens, such as hybrid aspen species, species produced by gene technology, and poplar.  
     
     
         5 . The use as claimed in  claim 1  or  2 , characterized in that at least 30% of the fibres of the mechanical hardwood pulp originates from aspen and/or from wood species of the genus  Populus.    
     
     
         6 . The use as claimed in  claim 1  or  2 , characterized in that the mechanical hardwood pulp contains at least 50% fibres that originate from aspen and/or wood species of the genus  Populus.    
     
     
         7 . The use as claimed in  claim 1  or  2 , characterized in that the mechanical hardwood pulp contains 70-100% fibres that originate from aspen and/or trees of the genus  Populus  and 0-30% fibres that originate from soft woods and/or other hard woods.  
     
     
         8 . A method for the manufacture of thin base paper, in which method a paper web is formed from a fibre raw material for a paper machine, characterized in that the fibre raw material is formed by combining precipitated calcium carbonate (PCC) with mechanical hardwood pulp and chemical softwood pulp, and ≧20 wt-% of the fibres of the mechanical hardwood pulp is included in the fibre size fraction of <200 mesh and 10-40 wt-% of them is included in the fibre size fraction of {fraction (28/48)} mesh, the brightness of the mechanical hardwood pulp is ≧75, the particle size distribution of the precipitated calcium carbonate is 90%≦9 μm, 50%≦5 μm and 20%≦1.5 μm, and the basis weight of the base paper is 25-150 g/m 2 .  
     
     
         9 . A method as claimed in  claim 8 , characterized in that the brightness of the mechanical hardwood pulp is ≧77, the particle size distribution of the precipitated calcium carbonate is 90%≦6.3 μm, 50%≦2.7 μm and 20%≦0.8 μm, and the basis weight of the base paper is 25-80 g/m 2 .  
     
     
         10 . A method as claimed in  claim 8  or  9 , characterized in that the mechanical hardwood pulp has been manufactured from aspen and/or from wood species of the genus  Populus.    
     
     
         11 . A method as claimed in  claim 8  or  9 , characterized in that the mechanical hardwood pulp contains CTMP pulp or pressure groundwood (PGW) or a combination of them, and the hardwood pulp has been manufactured from wood species of the genus  Populus  selected from the group of the following species:  P. tremula, P. tremuloides, P. balsamea, P. balsamifera, P. trichocarpa, P. heterophylla , aspen species crossbred from different mother aspens, such as hybrid aspen species, species produced by gene technology, and poplar.  
     
     
         12 . A method as claimed in  claim 8  or  9 , characterized in that at least 30% of the fibres of the mechanical hardwood pulp originates from aspen and/or wood species of the genus  Populus.    
     
     
         13 . A method as claimed in  claim 8  or  9 , characterized in that the mechanical hardwood pulp contains at least 50% fibres that originate from aspen and/or wood species of the genus  Populus.    
     
     
         14 . A method as claimed in  claim 8  or  9 , characterized in that the mechanical hardwood pulp contains 70-100% fibres that originate from aspen and/or wood species of the genus  Populus  and 0-30% fibres that originate from soft woods and/or other hard woods.