What is Papermaking and what are the different process of making it?
Roll of paper in a paper mil
The technique of papermaking is one revolutionary invention by humans. Papermaking was first invented in China by an official of the Imperial Court of China named Cai Lun (Ts’ai Lun) in about 105 CE. The Chinese used the bark of trees to make papers, but these papers were uneven and rough. Even before the Chinese invented the technique of papermaking, Ancient Egyptians had already discovered the use of paper by 3000 BCE. It was made of papyrus found on the banks of the River Nile. The art of papermaking then gradually spread to Central Asia by 751 CE and reached Europe by the 13th century. There were papermills in Spain, Italy France and Germany by the 14th century.
Paper is made from the pulp of wood or by recycling. Coniferous trees like spruce, pine, Fir, Larch, Hemlock, Eucalyptus, Aspen are used to manufacture paper. Sometimes plant fibres like cotton, flax, bamboo, esparto grass, jute and hemp are used for making paper. These fibres are called cellulose. Today more than 90 to 95% of paper is made from wood pulp. Recycled paper is now mostly used over wood pulp.
To produce paper, in the first place raw wood is converted to pulp. Since it has abundant water, it is then spread in a paper machine to squeeze out any remaining water. Next is the coating with chemicals for texture, strength, gloss, and quality. Then the papers are rolled in paper sheets and are then cut into desired sizes as required. The pulp mixtures can be bleached with various colours to bring out the desired colour too.
Papermaking is done either through mechanical method or chemical method. In mechanical papermaking or the groundwood method, wood is reduced to pulp by grinding against a revolving stone. This method removes very little lignin (natural polymer) and so generally produces low-quality paper. These papers are mostly used for newsprints, catalogues, telephone directories, paper tissues and towels.
The chemical method of papermaking is the most common method for making paper. In this method, chemicals are used to separate lignin from the fibres. Paper produced through chemical pulping are of higher quality. Chemicals such as alkalis, sodium sulphide or sodium hydroxide are used to produce while producing paper. German inventor Carl F. Dahl is known for developing this method papermaking. He invented sulfate (kraft) for making stronger paper which then came to known as the “kraft process”.
Besides the mechanical and chemical process of making paper, it can also be crafted by hand too.
The Fourdrinier machine is the first machine to produce paper in a continuous roll. It was invented in 1798 by Nicolas-Louis Robert in France. Henry and Sealy Fourdrinier of England further modified and patented this machine.
The use of paper is not limited to write, but with time it has developed to be used in various forms like decorating, carton, packaging, toilet rolls, paper towels etc.