Paper processes - Pasta production

Paper is perhaps the most widely used material in the world, in the various forms in which it can be produced: printing and writing paper, technical paper, flat board, corrugated board, packaging... It can even be used for purposes other than communication and packaging: many so-called technical papers are produced for use in the design of parts for automobiles or electrical components.

As we'll see in the following paragraphs, there are various techniques for preparing the raw material (wood or annual plants), but the basic principle behind the formation of a sheet of paper remains the same: a suspension of paper fibers (pulp) is deposited on a wire, which allows the fibers to drain and form bonds, then dewatered by pressing and dried. Only the technologies used have been modernized. The basic principle has remained the same since the invention of this material so useful to mankind.

The vast majority of paper or cardboard (a combination of different layers of paper) is produced from wood fiber. But any lignocellulosic material can be a potential source of paper fiber. This is why many annual plants (wheat or rice straw, bamboo, reed, flax, hemp) are used, especially in forest-poor countries.

There are two main types of pulp manufacturing process: mechanical processes that separate the fibers using a defibrator or refiner, and chemical processes that dissolve the lignin.

These processes are described in this article. The next issue of [J 6 901] will present the manufacturing processes for paper and cardboard.