To applications such as newsprint, toilet tissues, and paperboard as they tend to

yellow on age due to the high content of residual lignin (20–25%).

Semi-chemical pulps with a typical residual lignin content of 10–15% represent

The transition from mechanical to chemical pulps. There are several types of semichemical

Pulps in production, but the most important of these is Neutral Sulfite

Semi-Chemical (NSSC). NSSC is made primarily from hardwood species, and is

Noted for its exceptional stiffness and high rigidity. Its primary use is for the production

Of corrugating medium as well as printing papers, greaseproof papers,

And bond papers.

Handbook of Pulp. Edited by Herbert Sixta

Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

ISBN: 3-527-30999-3

©2006 WILEY-VCHVerlag GmbH&Co.

Handbook of Pulp

Edited by Herbert Sixta

Kraft pulp is noted for its superior strength characteristics, and can be used in

Virtually all paper and paperboard grades in order to improve strength properties.

In fact, the word kraft is the Swedish and German word for strength. Unbleached

Kraft is usually made with softwood and is used primarily in furnishes of kraft

Linerboard, wrapping paper and bag papers such as grocery bags. Semi-bleached

Kraft is used in furnishes of such grades which do not require high brightness,

Like newsprint and other groundwood-based papers. Bleached kraft is used in a

Much wider range of products than either unbleached or semi-bleached. Its greatest

Importance is in the printing and writing grades. In these grades, softwood

Kraft is used for its strength characteristics, while hardwood kraft, having shorter

Fibers, is used for its superior printing properties.

For dissolving pulp production, only acid sulfite cooking and the prehydrolysis

Kraft process are of major practical importance. Unlike paper-grade pulping, the

Acid sulfite process is the dominant system for the production of dissolving pulps,

and accounts for approximately 60% of the total production. Compared to papergrade

Production, the manufacture of dissolving wood pulp represents a niche

production. However, the high demands for cellulose purity and reactivity – as

well as its manifold routes of utilization – are the reason for its advanced state of

Technology within the pulp industry.

In this chapter, the main emphasis is placed on a comprehensive discussion of

The physical and chemical properties of dissolving pulps because they serve as

Appropriate substrates of which many aspects of pulp characterization may also

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