The Paper Making Process, Part 1

Paper is used for writing and printing, for wrapping and packaging, and for a variety of other applications ranging from kitchen towels to the manufacture of building materials. In modern times, paper has become a basic material, commonly found in almost all parts of the world. The development of machinery for its production in large quantities has been a significant factor in the increase in literacy and the raising of educational levels of people throughout the world.

The basic process of making paper has not changed in more than 2,000 years. It involves two stages: the breaking up of raw material (which contains cellulose* fiber) in water to form a pulp (i.e. a suspension of fibers*), and the formation of sheet paper by spreading this suspension on a porous surface, and drying, often under pressure.

Records suggest that paper was first made in China around AD 105. The technology was practiced solely in China for the subsequent 500 years, and then spread to Japan in 610, and later into Central Asia. It appeared in Egypt about AD 800, but was not manufactured there for another 100 years. A variety of raw materials were used and these included mulberry bark, old rags and hemp.

Paper was introduced to Europe by the Moors on their invasion of the Iberian Peninsula, and the first mills were established in Spain in about 1150. The craft then spread into most of the rest of Europe during the next two centuries. The development of printing technology in the 15th century saw the start of the widespread publication of books and this greatly stimulated the paper-making industry. The first paper mill in England was established in 1495, and the first such mill in North America in 1690. A crisis arose in the early 19th century as raw material for paper production was in shortage. European papermakers had grown used to using rags for paper manufacture and the shortage forced manufacturers to seek alternative raw materials. This gave rise to the use of wood for paper manufacture.

The solution to the problem of a cheap, readily available, raw material for paper making was achieved by the introduction of the groundwood* process of pulp making about 1840. At the same time, technological advances in paper making technology were taking place with the development of the first practical papermaking machine by Nicolas Louis Robert in 1798. Later, this machine was further improved, and put into manufacture, by the British brothers, Henry and Sealy Fourdrinier, their name still being closely associated with paper-making machinery today.

Fact File

  • More than 286 million tonnes of paper and board were produced in 1994
  • 34% of all paper produced is derived from recycled materials
  • 10 to 17 trees are required for one tonne of paper (approximately equivalent to 7,000 national newspapers)
  • It takes 2.7kg of wood, 130g of calcium carbonate,8g of sulphur, 40g of chlorine and 300 liters of water to produce 1kg of paper in a large scale paper mill.
  • The pulp and paper industry is the fifth largest industrial consumer of energy, accounting for 10% of all industrial energy consumption (although energy efficiency within the industry has improved greatly, and continues to improve)
  • In the USA, the papermaking industry is amongst the highest polluters, the major outputs being biochemical oxygen demand and total suspended solids, with significant outputs of CO and volatile organic compounds.

Today’s paper-making plants are capable of producing 1,000 tonnes of pulp and paper per day, using sophisticated technology based on chemical as well as mechanical processes for reducing raw materials to pulp. Modern day raw materials are many and varied, depending on availability, cost, geographical location, etc. These are covered more fully in a later chapter.

Hand paper-making has enjoyed a major revival over the past 30 years, using new and innovative approaches to this ancient craft. Handmade paper has a unique texture and an individual quality that makes it not only a surface to write, paint, or print on, but an object of beauty in its own right. In addition, the versatility of paper in its wet form has led artists to experiment with paper-making as an art medium, creating two- and three-dimensional images of textural richness and diversity, some on a vast scale. This Technical Brief aims to cover only the area of small-scale papermaking technologies for application in developing countries.

For this purpose we will define scale in paper-making as shown in Table 1 below.

Category / Output (tonnes of paper per day – t.p.d.)

  • Large scale / More than 100 t.p.d.
  • Medium scale / Between 30 and 100 t.p.d.
  • Small scale Less / than 30 t.p.d., including hand-made paper

Typically, a hand-made paper producer will manufacture only a few tonnes of paper per year (depending on the number of employees) often for a highly specialized market. Mechanized plants, on the other hand, only become economically feasible when dealing with an output above several tonnes per day. In India, where paper making machinery is manufactured indigenously, and hence costs are kept lower, mechanized paper making on a small scale is very common, with plants operating at outputs of 5 tonnes per day and upwards.

source: www.practicalaction.org

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