One of the world�s most important and useful products is Paper. What do a cardboard box, a paper money, and a book have in common? They�re all made from paper. Without it, there would be no newspapers, magazines, writing paper, or greeting cards. There would be no paper bags or boxes, gift-wrapping, or toilet paper. Take a look around you. How many things can you see that are made from paper?
How is paper made?
Paper is made from tiny fibers from plants. You can make paper from many types of plant fibers. Papermakers use fibers in straw, leaves, bamboo, sugar cane, and bark. Most paper are made from wood fibers. The most important trees used for making paper are softwood trees. Softwoods include pine, fir, hemlock, and spruce. The long fibers in softwoods are ideal for making many kinds of paper.
Paper is made in two stages. The first stage is to remove the fibers from the wood. This is done by grinding the wood or cutting it into chips that are softened with chemicals. The wood fibers are then mixed with water to make a souplike substance called pulp.
The second stage is to spread out the pulp, press it flat, and dry it. This makes the fibers stick together in thin sheets. Some paper is still made by hand. But most paper is made by machines at factories called paper mills.
Characteristics of different types of paper.
Different kinds of pulp make different kinds of paper. Pulp made by grinding is called groundwood pulp. It�s inexpensive to make, but the grinding breaks the wood fibers into very short pieces. Groundwood pulp is used to make cheap papers, such as
Newsprint.
Pulp made using chemicals is called chemical pulp. The chemicals separate the fibers from each other but do not break them. Chemical pulp is used to make stronger, longer-lasting paper for use in fine books and magazines.
The best writing paper and stationary comes from cotton and linen rag fibers. Thin rag fibers are long, strong, and make very durable paper.
Fiber from recycled paper is used to make paper towels, napkins, and tissue. Paper for printing is treated with special chemicals so that the paper won�t absorb ink and cause fuzzy lines and make it hard to read.
How papermaking machine work.
The main part of a papermaking machine is a wide belt made of tightly woven wire mesh. The belt moves in a loop, and it keeps moving all the time. Pulp is poured evenly onto the belt at one end of the machine. As the belt moves along, water drains from the pulp. The fibers remain, leaving a mat of wet paper. The belt goes through metal rollers that squeeze out more water. Now the paper is strong enough to be lifted off the belt. It passes between heated rollers that dry it completely. Finally, the paper is pressed tightly between cold metal rollers that make it smooth. The finished paper is wound onto large rolls or cut into standard sizes, packed and ready for usage.