Increased Use of Hardwood High Yield Pulps for Functional Advantages in Papermaking, 2001 Papermakers Conference Proceedings

Ron Reis--Increasingly, high yield pulps (HYPs), in particular hardwood HYP produced from aspen, birch and maple, are being used for their functional advantages in papermaking rather than as lower cost substitutes for hardwood bleached kraft pulp (BKP). The advantages are evident in the following applications:

* in uncoated printing and writing grades, where there are lower amounts of calendering, the higher bulk hardwood HYP allows lower basis weights and improved stiffness, bulk and opacity while maintaining printing properties;

* in coated papers made with newer paper machines and new calenders like the Janus or Optiload calenders, the higher bulk of the hardwood HYP is preserved, allowing lower basis weights and improved stiffness, bulk, and opacity, which has led to the creation of new paper grades;

* in multi-layer ivory board grades, where hardwood HYP has significantly replaced softwood HYP in the inner plies, allowing formation and printability to be improved and producers to be more competitive with solid bleached board grades; and

* in carbonless and specialty papers like release papers, where the improved formation and porosity of hardwood HYP provides superior base-sheet properties compared to hardwood BKP.