How can we use more Recycled Paper for Christmas? Does paper have Chlorine ?Whats recycled paper made of?
Who invented Paper? When was Paper invented?
Egyptians seemed to be the first ones to do everything. They used papyrus which was like paper in 4000B.C. And Chinese invented what looks like current day paper in 105A.D. Cai Lin who was in the imperial court came up with paper which was a cheaper alternative to silk and bamboo tables which they used to write on.
Around 600A.D. the Buddhist monks spread the art of paper making to japan and the war fought around 750A.D spread the paper technique to the Arabs.The Arabs built the first Paper mill in 1000A.D. in Spain and it continued until the Christian Europeans drove the Arabs out of Spain. This then spread to the rest of Europe, from Spain to Italy,France and Germany. Though paper was in use, people used the pen to write texts. A goldsmith named Johan Gutenberg from Germany invented the printing press
which revolutionized the sharing of knowledge.
How is paper made? Paper Manufacturing Process.
Paper initially was made from old clothes and fabrics. But Rene-Antoine Ferchault de Reaumur from France
studied the wasps. Wasps made their hives from chewed up wood. An Englishman named Hugh Burgess came up making a better wood pulp and basic manufacturing process to make paper. The quality of the paper was improved by an Amarican named C.B. Tilghman in 1867. He added sulfites to the pulping process.
Trees are made mostly of 45% cellulouse,30% hemi cellulose, 23% lignin which binds the cellulose fibers
together and a small portion of terpenes, resins, and fatty acids. The process of making paper consists of a number of steps,
The process starts with cutting trees, and taking the bark off before the wood is used for papermaking. A large, spinning and rotating drum that makes the logs move around is used to debark the trees. The debarked logs are then cut into chips.The chips are made into pulp. This is done by treating them chemically and mechanicall
The pulping process separates the cellulose and hemi-cellulose from the lignin and removes other tree oils and resins. This process is important because the remaining fibers
are used to produce the product we know as paper. There are two main pulping processes,
Chemical pulping involves treating with acidic or basic liquors, to form Cellulose, the main fibrous component in wood. Chemical pulping produces very pure cellulose fibers. It is the most common form of chemical pulping in North America. In Kraft pulping the wood chips are cooked in sodium hydroxide and sodium sulfide to produce a strong dark brown pulp. It is a highly efficient process for removing lignin and resins in softwoods while still producing a high-quality pulp.Chemical pulping releases Hydrogen sulfide gas which smells like rotten eggs. The use of scrubbers has reduced thi sproblem to a large extent. About 45-50% pupl is acquired by Kraft process.
Mechanical pulping: The fibres have to be beaten to render them for papermaking and the individual fibres separated and softened to gain strength.The softening is done by mechanical pulping.Logs are debarked by a rotating metal disk to produce pulp.Though the percentage of usable pulp by this mentod is higher,the resulting paper quality is lower.About 95 per cent of the wood feeded is turned into pulp which is much higher yield compared to the Kraft process.The paper quality is lower and mechanical pulping being an energy-intensive process tears down the cellulose which decreases its strength so is not as efficient as Krafts.The lignin and tree resins are left in the pulp.
Mechanical pulping produces paper which has higher lignin content,the paper produced by this process darkens when exposed to sunlight. It is used mostly used for newsprint, telephone books and places where high quality of paper is not really needed. Another variation in the mechanical pulping process is the steam conditioning before the chips are pulped. This reduces energy consumptionand is called thermo-mechanical pulping (TMP). Another method is,chemo-thermo mechanical pulping (CTMP).The wood chips are soaked in sulfur-based chemicals prior to steaming. This helps the lignin and resin to be extracted from the wood, and a stronger pulp is obtained.
The next important step is Bleaching. It is used to purify and clean the pulp. Bleaching removes lignin, which affects the purity of the fiber
. Chemical bleaching in Kraft mills use chlorine gas to remove the remaining lignin and chlorine dioxide bleaches the left over lignin fibres. In mechanical pulp bleaching operations peroxide is used.
The paper machine involves four sections:
It starts with a step called stock preparation. Here wood fiber is mixed with 99% water and 1%minerals. In modern paper machines, the water is drained from the top and the bottom resulting in a web paper.
The next step is the press section. The paper is squeezed between rollers and a felt.which removes more water from the paper. After the press section, 40-50% of the paper is still made up of water.
The dryer section, has dryers which help in furthur removal of water from the paper.
After the dryer section, ppaer is left with 2-6% of water.A size press coater is applied which is a light coating of starch and minerals. This makes the paper strong and smooth.The paper is dried again in the after-dryer section and is wound into a giant roll.
Blade Coater is used to spray a thin coat on the paper which makes it good for different kinds of printing.
Supercalender process makes the paper glossy and smooth by putting the paper under a lot of pressure and then heating it up. After supercalendering, the paper is cut into smaller rolls.
Sheet converting is the last stage in papermaking. The paper rolls are cut into sheets and are packaged for delivery.