Effects of shoe pressing on fine paper properties

A series of trials has been conducted on a pilot paper machine to investigate the effect of shoe pressing on the web solids contents and properties of fine paper. The machine was operated at speeds of 600 and 700 m/min and the shoe press nip load ranged from to 50 to 700 kN/m. Adequate bulk and a solids content of 45% were obtained when fine paper was pressed by two lightly-loaded roll presses and a shoe press. Solids content in excess of 47% were obtained when paper was pressed by four heavily-loaded presses, one of which was a shoe press, but the bulk was about 10% lower than the bulk of paper lightly pressed in a 3-roll press. Pressed to equal solids contents, paper pressed by a shoe press had a higher bulk and opacity, but lower Scott bond and strength than paper pressed in roll presses only.