| 摘要 |
<p>A paperboard product (w) having at least one layer of bleached or semi-bleached pulp and having improved smoothness and reduced bulk loss. For paperboard having sizing without pigment, the smoothness on the printed side as measured by the Parker test is better (lower) than 6.5 when measured using a pressure of 10 kgf/cm2 while the smoothness measured by the Hagerty/Sheffield test is not below 280 Sheffield units. For paperboard having sizing with pigment, the Parker smoothness is less than 5.0 and the Hagerty/Sheffield smoothness is not less than 180 Sheffield units. The web is finished by applying temperature and moisture gradients to the web and then smoothing the web surface using extended nip calendering, which comprises a heated roll (42), a conformable belt (44) and a backing shoe (72). The surface of the calendering roll (42) is maintained at a temperature of 250-400 °F.</p> |
