Stuff You Should Know: Paper Processing

Have you ever wondered how a tree becomes a notebook?
By: Garret Barner

Paper is essential to our daily lives. Whether it be in the form of a hard copy essay, a massive financial accounting book or scrap paper used for writing notes in class, paper is essential. The average American uses 680 pounds of paper per year, which equates to about 7 trees per year. According to Ward Patterson, Principia’s mail and copy services director, Principia uses about 1.5 million pieces of generic 8.5×11 paper per year. This equates to about 3,000 pieces of paper per student, per year.

Dr. Karen Eckert, Principia College professor and Director of the Principia College Center for Sustainability, gave the Pilot recycling statistics for paper during the years 2011 to 2013. Overall our usage of paper has decreased, with Principia moving from 26.91 tons of recycled paper in 2011 to 24.49 tons of recycled paper in 2013. Due to a transition to single stream recycling in late 2013, the amount of recycled paper cannot be known today.

It is important to note is that the paper Principia College uses is 30 percent post-consumer recycled content paper, and the virgin fiber is sourced from sustainably harvested forest products.

Trees are typically the main source of material for creating paper, but in the past there have been restrictions on the types of trees that can be used in this process. Now, with better technology, it does not matter whether the tree being used is considered a hardwood or a softwood tree. Paper cannot only be created by trees; paper can also be created through bamboo, straw, sugarcane, and linen.

After the initial cutting, limbing, and debarking of the tree, it is made into wood chips, then processed with chemicals sodium hydroxide and sodium sulfide inside giant vats called digesters. This mixture of chemicals and wood chips is boiled and mixed until only pulp remains. It is then subsequently filtered.

After the initial chemical process, the pulp undergoes a pounding and squeezing treatment, which is officially called “beating.” During this process, the various filler materials are added to the pulp to help with the “sizing” of the paper.

These filler materials can range from chalks, clays, or chemicals such as titanium oxide. The various fillers determine the way the paper will react with various inks in a process known as “sizing” the paper. Typically, without any sizing, paper will be too absorbent; depending on the paper’s future use, proper sizing is imperative to the papermaking process.

Following the addition of the fillers, the processed pulp is fed into mammoth machines. The most common machine currently used is called the Fourdrinier machine. Pulp is fed into the machine and placed on a moving belt that is made of a fine mesh screen. The pulp is then put through multiple rollers, which flattens the pulp and squeezes out the liquid held by the pulp.

After the initial pressing, the paper moves to the secondary press section of the machine where rollers of wool felt squeeze the paper together. The paper is then passed over heated cylinders to remove excess water.
Finally, paper is wound onto large reels for further processing depending on what the paper is going to be used for. The machine used for the final process is called a calendar. A calendar consists of large metal rollers that can apply certain finishes to the paper, making it anything between cardstock-like paper or parchment-like paper.

Coatings can be added in this final process to make the surface of the paper practical for its coming use. Chemicals are not the only thing applied to paper in this final stage–fine clay can also be utilized. Finally, the paper is cut into a desired size, packaged and shipped off to its location of use or sale.

The paper making process is interesting and, with an increased knowledge of the process, you will hopefully be more impelled to reduce, reuse, and recycle your paper. At Principia, we are fortunate to have such strong advocates for recycling. On campus you can find a paper recycling container in each house and each academic building as well. Recycling is our future and it is essential that we do our part on campus.

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