Papermaking secrets were jealously guarded by the Chinese, until the 7th century AD, when Chinese papermakers were among the prisoners of war captured in a battle with an Arab army. The secret was uncovered and papermaking techniques started to spread across the world.
Today, woodfibre arrives at the mill as whole tree trunks, wood chips or paper pulp from other mills. Recycled or waste paper can also be used. End-uses for paper made this way include linerboard and fluting for onward conversion into cartons and boxes. Untreated wood pulp has a brownish colour and is often bleached to make it white. Pulp can be bleached with chlorine or chlorine compounds, as well as with oxygen or hydrogen peroxide. Sappi pioneered the Sapoxal oxygen bleaching process.
This world first is now an industry standard. Coated papers contain a layer of coating material on one or both side. The coating materials of pigments and fillers help to improve the printing surface of the paper. Printing and writing papers made from bleached chemical pulp are used for general printing, photocopying and stationery. Skip to main content Skip to navigation. How paper is made. While the basics of papermaking process has changed very little over the centuries, woodfibre only became the main raw material for mass paper production in the midth century.
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. Download this Project Learning Tree lesson plan on how to make paper. It includes screens, pulp, instructions and supporting resources. Your only cost is return postage. E-mail plt Idahoforests.
See h ow Clearwater Papers in Lewiston, Idaho turns wood chips and sawdust into pulp, the main ingredient used to make the many paper products we all use every day. Click here to watch. Paperboard is the material used to make folded cartons, liquid packaging, paper cups and plates and printing paper. It needs to be strong, uniform and clean. This video shows the process of turning pulp into products we use every day.
Most people know that paper products come from trees. It was here in that the first successful paper-making machine was developed. Henry and Sealy Fourdrinier were financial backers and enthusiastic supporters of the project, giving way to the name of the machine, the Fourdrinier. This machine became the standard design for paper-making machines, which remain virtually the same today.
Wood or cotton fibers are beaten until they break down into small particles, and the fibers are diluted with water to make pulp and placed in a reservoir. Pulp is then metered out in a continuous stream onto a moving wire screen. The moving wire is mechanically shaken side to side to distribute the pulp evenly across the screen and drain water. Suction boxes underneath the screen also help drain excess water.
The pulp is then transferred to a woven felt blanket and carries paper through a press roll which removes even more water. By varying the woven texture and the location of felts, the finished texture of the paper can be varied. Watercolor paper, for example, uses a very heavily textured felt, while the felts for drawing and sketch papers have very little texture.
At this point, the fibers have interlocked and the paper has dried enough to be passed through steam-heated cylinders. Without sizing, the paper would act like a blotter. The sizing seals the fibers individually or as a structure to provoke water holdout. The amount of sizing is adjusted based on the grade of the paper. For example, drawing papers have more sizing for water hold out, where watercolor papers require a different approach to allow absorbency while still maintaining an internal barrier.
After the sizing bath, the paper is re-dried.
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