Paper - A History

A few basic (layman’s!) facts about the wonder that is “Paper”

Its Origins and History:

The word “Paper” comes from papyrus. Whilst reeds from the lower Nile were used in Egypt 5000 years ago as the basic raw material to produce a sort of laminated mat on which they could write, the generally accepted origin of paper as we know it today was in China, in 105 AD. Paper consists of a web of cellulose fibres which, with the help of various additives, knit together to form a thin flat substrate suitable for a number of uses including writing, packaging, decorating etc.

 

After much experimentation, the original source materials evolved from cotton and linen, and thus old rags, plus straw, esparto grass, and hemp. The constituent fibres were separated via a refining or beating process and then mixed with water in a large vat. A mesh screen was then submerged in the vat and lifted up through the water, catching the fibres on its surface. When dried, this thin layer of intertwined fibre became what today we call paper. 

 

For almost 18 centuries, as the secret art of paper-making slowly spread across Asia and eventually into Europe (by the 12th Century), the product was in the form of hand-made sheets. The notion of paper being used as a practical everyday item did not develop until the 15th Century. When Johann Gutenburg perfected movable type and printed his famous bible in 1456, he not only spread the word of Christianity, but also sparked a revolution in mass communication. The birth of the modern paper and printing industry is commonly marked from this date.In the late 18th Century the first paper machines were devised, producing a seamless length of paper on an endless wire mesh with squeeze rollers at one end. The machine design was patented in 1801 by the Fourdrinier brothers, and this patent in essence continues to this day to be the mainstay for paper production worldwide. 

 

Woodpulp:

Demand for paper in the early 19th Century was now beginning to outstrip supply of raw materials, and finally wood was identified as a suitable, inexpensive and replaceable alternative. Wood is made up of cellulose fibres that are bound together by a material called lignin. There are two basic methods by which the cellulosefibres are obtained:

Mechanical: the wood is ground and beaten to “tease out” the fibres, and the resultant pulp is most commonly used for lower grade paper applications such as newsprint, and packaging qualities.

Chemical: the wood, after chipping, is cooked up in a boiler with caustic soda, other chemicals and often a bleaching agent to separate the lignin from the fibres.

 

The economics and indeed the resultant fibre quality of these two processes are very different. The yield of pulp from wood is almost twice as high with mechanical pulping compared to chemical pulping, with the process also being markedly less costly in terms of energy and chemicals required. The most noticeable difference in the paper produced from these two types of fibres is caused by the continued presence of lignin in mechanical pulp, which will over time rise to the surface of the paper (which is why newspaper turns brown if left in the sun...). 

Fibre and Paper Qualities:

Until the early 1960s the favoured material for woodpulp production was softwood, usually from pine and spruce trees grown mainly in cool Northern climates of Europe and North America. These slow-growing trees produce a long fibre, endowing the resultant paper with the positive benefit of high tear-strength. In the mid 1960s attitudes changed, and the various features of the pulp from faster-growing hardwood trees such as eucalyptus and acacia (mainly grown in Australia, Latin America, the South African continent and more recently Iberia) became increasingly attractive to both the papermaker and the end consumer. Though hardwood produces a short fibre (so lower tear-strength), it does meet the growing consumer demands for greater opacity, bulk, printability and softness. Paper manufacturers have applied their skills to develop products comprising a blend of soft and hardwood pulps, and this is now very much the preferred quality for printing and writing papers throughout the world.

Recycling:

This particular subject has now become a very high-profile concern for the “man in the street” and his or her perception of paper and its impact on the environment. With a view to retaining a balanced view therefore, it is important to spell out one or two key facts:

 

  • Paper cannot be recycled more than 5 or 6 times – otherwise the fibre becomes so short that it washes down the drain!.
  • Not all paper is recyclable - due to impracticality (e.g. laminated, plasticized etc), economics (e.g. collection, transport, de-inking), or the environment (e.g. use of additional chemicals, de-inking).
  • Quality (particularly tear-strength) and other characteristics demand some virgin fibre in the paper mix.
  • The recycling rate in Europe reached almost 65% in 2007.

     

  • Close to 70% of fibre used in the UK paper industry is now waste/recovered paper.
  • There is unfortunately a great deal of emotional misinformation on so-called “unnecessary felling of trees”
  • Tropical rain-forests do NOT provide wood for paper manufacture!
  • Forests felled for paper, almost invariably, have been planted to provide raw material for the industry.
  • It’s a crop - who objects to wheat being harvested?
  •  Concept of Sustainable Forestry - European forests have increased by 30% in 1990s (equivalent to the area of Cyprus every year..

    PFSE and Paper:

So, paper is commonly made from wood fibres which have been inter-twined into a substrate, held together and coated with various materials such as china clay and starch. During the paper-making process the majority of the fibres assume a predominant direction which becomes the “grain” direction of the paper, though obviously the web format ensures that there is adequate linking to give some cross-strength to the paper too. Nevertheless, identification of and benefiting from the grain direction is an absolutely key element to the PFSE design and construction. By building up a multiple layer of papers applied in different directions, the inherent strength of the furniture is achieved. It is comparable to the concept of ply-wood construction, where the composite strength is achieved by sticking thin layers of wood veneers in different grain directions, one on top of the other  (the source material is the same of course…..i.e. wood!).

Another important aspect of the PFSE construction concerns the type of paper used for making furniture. The base material for the furniture of course tends to be cardboard, often corrugated cardboard (which, again, derives its strength from this concept of a multi-layered sandwich), but it is joined together, and acquires additional strength, using strips of newsprint and flour-based adhesive which soaks into the paper strips and the outer surface of the cardboard. It is therefore vital that the paper used for this purpose has adequate absorption qualities so as to encourage the glue or adhesive to soak into the paper surfaces. If you hold a piece of paper up to a light, you can detect a sort of “cloudy” formation with some areas of the paper almost transparent, and others with thicker patches like clouds in the sky. This is referred to as the paper formation, and the higher quality the paper, the less marked this variability of composition is. BUT….the looser or patchier the formation, the better the absorption qualities are, and the more suited it is for PSFE purposes! Newspaper or newsprint is the best material because it is usually made from recycled and/or mechanically-produced pulp which tends to have a less dense formation, possibly fewer additives such as starch and china clay, and therefore a greater suitability to soak up glue.