English version.

Pulp Properties and Applications

Herbert Sixta

11.1

Introduction

Pulp represents the major raw material basis for two main applications: (a) for

Paper and board production, where the pulp fibers are mechanically modified to

Give a coherent sheet; and (b) for chemical conversion to products such as regenerated

Fibers and cellulose derivatives. The former is denoted as paper grade, the

Latter as dissolving grade pulp. Paper-grade pulp is by far the most dominant field

Of pulp production. With an annual production of about 190 million tonnes in

2002, paper-grade pulp accounts for almost 98% of the total wood pulp production

(see Chapter 1, Tab. 2, Tab. 3 in Part I). A large variety of different unbleached and

Bleached mechanical and chemical pulps comprise the raw material basis for

Paper and board products. The kraft process represents the dominating pulping

Technology (130 million tonnes in 2004), while the sulfite process (being the most

Important pulping method until the 1930s) continuously loses ground and finds

Application only in certain niche markets.

Sulfite pulp is characterized by rather week strength properties, and is typically

Used in products that require good sheet formation and moderate strength. Historically,

Sulfite has been most widely used in newsprint furnish. However, its

Importance in newsprint has been declining in recent years with the increasing

Use of stronger mechanical pulps such as thermomechanical pulp (TMP) and

Chemo-thermomechanical pulp (CTMP). However, their use is mostly restricted

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.

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