The effect of press draw and basis weight on woodfree paper properties during high-solids surface sizing

摘要

In high-solids surface sizing of up to 30% solids,less starch penetrates the sheet,which means the sheet requires less drying.However,less penetration means the internal strength does not benefit from the starch as much as it does in conventional surface sizing.To compensate for this loss of internal strength,the Huygen internal strength of surface-sized paper can be increased by reducing the press draw from 3% down to 2% or lower.Starch penetration is further reduced,however,when the press-to-dryer draw is decreased because the lower press draw decreases the porosity of the basesheet.Moreover,reducing the press draw to less than 2% decreases the elastic modulus of the fiber network and reduces the bending stiffness of the sheet.