How Paper is Made

You gotta have fiber!
Over the centuries, paper has been made from a wide variety of materials -- wood pulp, rice, water plants, cotton, even old clothes! But no matter what you use to make paper -- you need "fiber." Today's paper fiber comes mainly from two sources -- pulpwood logs and recycled paper products. In fact, much of the paper we use every day is a blend of new and recycled fiber.

From log to pulp.
Much of the paper produced in Idaho is made from "waste" -- the tree parts from logging and sawmill operations that can't be made into lumber. After harvesting, trees are cut into logs and are transported to the mill. At the mill, a debarker removes the bark from each log. The log is cut into boards of varying sizes. The wood that's left over is then converted into wood chips, about the size of corn flakes (though not as tasty in milk!).

The wood chips are then put into "pulp digesters" where they are broken down by steam and chemicals into a gloppy pudding of cellulose fibers and other wood components. In another process, the chemicals, wood resins, and wood lignin (sort of a natural glue in the wood) are removed. The cellulose fibers are cleaned and screened many times to get them ready to be made into paper.

From pulp to paper.
The paper pulp (from wood chips, recycled paper, or both) is fed into the paper-making machine. A pump sprays a thin layer of the liquid paper pulp onto a moving wire screen. This screen can be up to 20 feet wide, and can travel at speeds of 60 miles per hour. That's fast paper!

As the pulp is carried along by the screen, the water in it drops away, and the cellulose fibers become matted together, forming paper. While the paper is still damp, it is fed through a series of heated rollers which press it and dry it. The paper is then spooled into huge rolls, cut into various sizes, and converted into paper products.

From paper to more paper.
Recycling paper helps make sure we get the most out of every tree we use. And it helps keep paper from clogging up our landfills. Each time paper is recycled, the cellulose fibers get shorter, until eventually the paper won't hold together. That's why most "recycled" papers contain some new paper fibers mixed in with the old.

More information about paper and recycling, including a video about classroom papermaking: http://www.paperrecycles.org/school_recycling/index.html.

 

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