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Environment Forest Ecosystems Forest Industries Forest Management Forest Products Greenhouse Gases NAFI Submissions Policy and Politics Renewable Energy Sustainability |
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The Development of PaperTHE DEVELOPMENT OF PAPERPrehistoric Times The earliest and crudest forms of writing surfaces were cave walls and rocks on which prehistoric people drew pictures. Other pre-paper writing surfaces included cloth, clay tablets, palm leaves, wooden boards coated with wax or plaster and the inner bark of trees. 3500 BC The world's first paper-like material, papyrus used by the ancient Egyptians, came into use. It was made from the fibres of reed-like water plants called Cyperus papyrus. The word paper derives from the word papyrus. Circa 170BC Longer-lasting parchment took over from papyrus as the main writing material in Egypt, Palestine, Syria, and southern Europe. Animal skins were used to make parchment. They were washed then immersed in lime to rid them of hair and fat. Next the skins were stretched over a frame and thinned with knives and scrapers. Finally, they were rubbed with chalk and pumice. The end result was a tough, smooth writing surface. Parchment is still used today for some important documents, bookbinding, lampshades, and for drum, banjo and tambourine heads. Although paper was invented much earlier it wasn't until printing was developed in Europe in the 1400s that paper replaced parchment as the most widely used writing/printing material. Circa AD 105 It is believed a Chinese man called Ts'ai Lun, an official in the court of Emperor Ho Ti, invented paper as we know it today - made from cellulose fibres of plants or other fibrous materials. Ts'ai Lun found that if he soaked materials such as old rags or fishing nets, and plants like mulberry and hemp in water and beat them, the fibres separated to form a pulpy mixture. When the pulp was gathered on some cloth stretched across a frame and left to drain and dry, the fibres matted together to form what we now call paper. The oldest paper still intact today was made from rags about AD 105. At first, paper was used only for religious purposes such as written prayers or banners. Eventually bags, clothing, fans, lanterns, screens, umbrellas and other items were made from this versatile product. Circa AD 300 The art of papermaking was developed and improved to become widely used as a writing surface. Circa AD 610 Although China managed to keep its papermaking techniques secret for hundreds of years, they eventually reached Korea and later Japan. Circa AD 795 The paper industry was established in Baghdad (Iraq) and spread to India, Egypt and the Holy Land. 1000s The first European papermaking mill was set up in Spain. 1300s Paper mills were established in various European locations. Circa AD 1450 The invention of the printing press greatly increased the demand for paper to publish books. Late 1700s The first papermaking machine was built by Nicholas-Louis Robert. Early 1800s Rags were in short supply and a new source of fibres for papermaking was needed. Wood and other vegetable pulps were the answer. Rags, however, are still used today to make stronger, more durable paper. 1803 British brothers Henry and Sealy Fourdrinier improved the papermaking machine and built the first Fourdrinier machine that still bears their name. Present day The United States and Canada are the world's biggest producers of paper, pulp and paper products. Nearly 70 million tonnes of paper and cardboard are produced in the US alone each year. MAKING PAPER Most of the world's paper is made commercially from wood fibres, some from trees grown specifically for that purpose, others from recycled newsprint and other used paper products including packaging. Special cleaning methods remove ink from printed matter. Some paper is made from non-wood fibres like those of rags and various plants. The first step in making paper is separating the individual fibres by dissolving the lignin that holds the cellulose fibres together. The resulting mixture is called paper pulp. Three methods that can be used are: (i) Mechanical - a machine grinds the wood into pulp. (ii) Chemical - the wood is chipped and then cooked in a chemical solution. This method removes more unwanted residues so is used to make better quality paper. (iii) Semi-Chemical - chemicals soften the lignin before a machine separates the fibres. To soften the fibres and improve their ability to mat together a machine then pounds and squeezes the pulp. Colour in the form of pigments and dyes can be added to the pulp at this time, as can other materials needed to help preserve the paper and improve its appearance or quality or to make its surface suitable for writing on. There are two main machines used for papermaking - the fourdrinier machine and the cylinder machine. In the fourdrinier machine, a mixture of pulp and water flows continuously on to a moving wire-mesh screen. Water is sucked from the pulp, matting the fibres together. The sheet is transferred on to a screen of felt which passes through several presses to remove more water. The last of the water evaporates when the sheet moves over heated drums. With the cylinder machine, a cylinder covered by a screen rotates through a pulp vat and collects matted pulp on the outside of the screen. The pulp is picked up by a moving belt and water is then removed from it as with the Fourdrinier machine. Cylinder machines are used to make thicker paper and cardboard by placing sheets of matted pulp on top of each other. After being wound on to big reels the dry paper is "finished" in various ways. It might be cut into sheets and packaged, or passed through steel rolls to be coated with substances that make the final product glossy, smoother or more opaque. Alternatively, it can be made into bags, boxes and other products. |
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