Facts About Paper & The Paper Industry

The ancient Egyptians made a rough type of paper for scrolls from the papyrus plants growing along the Nile River.  The pith of the plant was cut into strips and pressed to make a smooth writing surface.  The Latin word, papyrus, is even the root of our modern word for paper.  The Chinese made their first paper from old fishing nets around 200 B.C.

Paper as we know it today was invented by Ts’ai Lun, a Chinese court official, in 105 A.D.  His likely formula included mulberry bark, hemp and linen rags mixed with water.  He mashed this mixture into pulp, pressed it thin to remove the liquid, then hung it in the sun to dry.  His invention was so important that the Emperor made him a noble.

The Japanese have also made paper by hand, known as tosha-shi, for centuries, and continue to teach this craft today.  The Arabs learned of papermaking from some Chinese prisoners of war in 793 A.D.  They improved on the process, and spread their methods across the Middle East and to Spain, where the first paper machine was started in 1100.  The primary catalyst for papermaking in Europe was Gutenberg’s introduction of the printing press in 1456, which drove up the demand for paper on which to print books.  Paper at that time was made from linen and cotton rags.  Papermaking finally reached England in 1494.

In the early 1700’s, French naturalist Réné de Réaumur noticed how the material in a wasp’s nest resembled paper and got the idea for using wood pulp to make paper.  The first patent for making paper from deinked fiber was issued in London in 1800.  It was 40 years later that pulping methods were developed in Germany and Nova Scotia that would allow the large-scale commercial production of paper.  In 1879 the “Kraft” pulping process was invented by C.F. Dahl, a German chemist, allowing wood to finally replace rags as the primary ingredient in paper.

William Rittenhouse built the first American paper mill in Germantown, near Philadelphia, Pennsylvania in November of 1690.  It made about 100 pounds per day of writing paper from recycled cotton, linen and some used paper.  As demand for paper increased, the demand for rags to make it also increased to a point where “rag wars” were common in the mid-1700s.  In 1867, the first American groundwood pulp mill opened in Massachusetts.

Benjamin Franklin was the first paper merchant in America; he helped start 18 paper mills in the Virginia area.  Two factors – the growth of newspapers and the expansion of businesses – in the late 1800s, and the resulting demand for more paper, drove many innovations in papermaking at the time.  By then, trees had become the main fiber source for the paper industry.  By 1900, U.S. papermakers produced 14,000 tons of paper a day.

The first Kraft mill in America was built in 1911 in Pensacola, Florida.  By 1937, Kraft (German for "strength") was the predominant chemical pulping process in the industry, and remains so today.  It has three chief advantages:  the chemicals used in it can be reclaimed for reuse, it produces a great amount of energy that can be harnessed to power machinery, and it can pulp one of the most common trees in America, the pine tree.  It also produces longer and cleaner paper fibers than mechanical pulping processes, albeit with a lower yield from the wood fiber that was input at the beginning of the process.  Chemical pulp is used for making higher quality grades of paper, while mechanical pulp is used for grades like newsprint and directory paper.

In 1916, Thomas Jasperson was granted a patent for making paper from de-inked wastepaper.  His method was the beginning of the paper recycling process as we know it today.

Many of these grades further identify the material based on variables like the method of pulping (chemical vs. mechanical), type of fiber (hardwood, softwood, or wood alternatives), previous use (newspapers, magazines, office paper, etc.), or source of the paper (mill overruns, postconsumer, etc.).  For example, to make the shiny finish on magazines, the paper may be coated with clay or with varnish.  Which one is used may make a difference in how that paper can be recycled.  The specifications for each grade also outline the amount of “prohibitives” and “outthrows” that can be included in each load of material. 

Most paper mills also have their own specifications for the grades of paper they can use in their deinking or manufacturing process.  These take into consideration even more factors like moisture content, cleanliness and additives used on the paper.
 

When paper recyclables are collected from curbside bins or community drop-off sites, this is only the first step in their long journey to becoming other products.

Their next stop is a “materials recovery facility”, or MRF (rhymes with “surf”).  This is a large, warehouse-type facility with conveyor belts and sorting machinery that separate the items into groups of plastics, metals, glass and paper, then further sort each type of material into marketable commodities.  Hand-sorting is required for some items.

Paper recyclables may be shredded and baled at the MRF, or sent to another facility for this.  They may also be “loose-loaded” onto trucks, depending on the needs of the end user who will be buying them.  The paper is transported by truck, rail or ship to the mill that will convert it during the next step.

The paper’s journey can vary widely here, again depending on the end use.  If it’s being made into something like insulation, hydromulch, or another use that doesn’t require it to be very white, it will go directly to the plant manufacturing the product.  Sometimes it goes into storage until needed.  Other times it may be shipped overseas to mills who need it there.  Depending on market conditions and available storage space, there have even been times when paper collected for recycling had to be landfilled due to lack of demand for that grade.

Some of the products that can be made from recycled phone books include (from top left):  packaging for snack foods & other consumer goods, as well as rolls for paper towels, yarns & toilet paper; cellulose insulation that is blown into the roofs & walls of homes; backing & facing paper for gypsum wallboard; roofing felt & shingles; weed barrier; and hydromulch.

If the recycled paper is being made into new paper, such as newsprint or directory paper, it must first be cleaned, de-inked and bleached.  Mills use a variety of methods for this.  The two main ones are called washing (for small ink particles) and flotation (for large particles and “stickies”).  Some mills have de-inking facilities at the same location as their paper-making machines.  Others buy pulp that has already been de-inked by other companies.

At the paper mill, the de-inked pulp is usually mixed with some virgin pulp from trees.  The reason for this is that fibers become shorter each time they’re sent through the de-inking process, and some fiber is always lost in the process.  New pulp has longer fibers and helps to make the paper stronger.  This is why papers are available with various percentages of recycled content.  The wood pulp has been separately prepared and refined before being combined with the recycled pulp.

Once the pulps are mixed together, the lumpy, off-white mixture looks something like oatmeal.  After further refining, it becomes more like Cream of Wheat (to carry on the breakfast analogy).  It’s then spread onto fine wire screens (in a machine called the “former”) to form a massive sheet of very wet paper – about 80% water.  Next, it passes through the “press” section of the machine to make it smooth and uniform in thickness.  Water is pressed and vacuumed out of the sheet to make it about 50% water.  The long sheet is then passed through a series of hundreds of rollers as warm air is blown across them to dry it (see a diagram of this on the next page).  Then, it is fed through a series of rollers known as a “calender”.  The calender works something like an iron on clothes, removing any irregularities in the huge sheet of paper and polishing the surface of it.

At the end of the line, it’s fed onto large spools on the “reel” to make a roll about 30 feet across, which is known as a “parent roll”.  One of these rolls can weigh up to 20 tons!  The parent rolls are then placed on the “winder” to be cut into smaller rolls, whose size depends on their intended use.  Finally, each roll is wrapped, weighed, labeled and shipped out to the mill’s customers.  The wrapper is very thick, and likely contains a chemical treatment to control moisture absorption.  It also protects the roll from damage during shipping.

Paper that’s being made into items such as envelopes, cups, plates or tissues must go to a converting plant before it becomes the products with which you’re familiar.  These facilities contain machines that further cut, fold or shape the paper into the finished products and package them for sale in stores.
 

As much as 35% of the weight of recycled paper received by a mill may actually be something other than paper!  The flowchart on the next page shows just some of the foreign materials that show up at a mill in loads of recycled paper.  The ink, stickies, small fibers, and other wastes produced by paper recycling are collected and put to good use.  After the water is removed from it, this material can be burned to produce energy or composted.  Sometimes it’s used to make concrete or asphalt for roads.  Portions of it may have to be landfilled, depending on its content.  Making sure the paper you recycle is free of contaminants like plastic bags, string, food residue, or tape, is a great way to help reduce the wastes produced by recycling.

Even though recycling paper produces some waste products, it also eliminates many of the pollution-producing activities involved in harvesting and processing timber.  Logging and transportation of the felled trees are the obvious ones here, but there are others.  For example, it takes much more water to break down wood into fiber than to clean and de-ink recovered paper fiber.  There are also substances other than fiber in wood.  One of these is lignin, a glue-like substance that holds the wood in a tree together.  These must be removed from the harvested trees and become waste products for the mill.

An additional consideration is emissions produced by the paper mill.    One of the waste materials produced by using chlorine to bleach wood pulp is dioxin, a strong carcinogen.  Recovered fiber does not require as much bleaching, and it can be accomplished with milder chemicals like hydrogen peroxide, which creates only water and oxygen as by-products.  Another example is the sulphur smell often connected with paper mills.  This comes from the Kraft method of processing wood pulp into fiber for papermaking.  When the wood pulp is eliminated from this process, so are the mill’s sulphur emissions.  Since this odor is one of the reasons some communities do not want a pulp mill located near them, switching to recycled fiber makes the mill a better neighbor to the community where it is located.
 

Several things about the nature of phone books make them more difficult to recycle than some other grades of paper.  The cleaning process for fiber begins with the recycled material being dumped into a large vat and mixed together with water and solvents, something like a cake mix in a mixer.  Phone books are a bound book of paper that takes longer to break down in this process than does loose paper.  This drives up the cost of manufacturing for the mill.

Secondly, phone books are bound together with glue.  There are two types of glue that can be used in this binding; one is known as “hot-melt”, and is similar to what you use when making crafts with a hot glue gun.  This type of glue does not dissolve in water.  The other type of glue is water-soluble, more like the bottled liquid glue used in many schools.  Depending on the de-inking process, one type of glue may be preferred over the other.  Most mills today use a de-inking process that favors the water-soluble variety of glue.  If they receive a load of phone books that has the wrong kind of glue for their manufacturing process, it can damage their machinery or create flaws in the paper made from it.

Third, the yellow pages in phone books contain a large amount of ink.  This is a new problem in recent years that happened when the books began featuring ads with white backgrounds.  In the “old days”, the yellow pages were printed on paper that was dyed yellow.  When customers began asking for ads with a white background, however, the paper needed to be white, so the yellow color of the pages had to be applied with ink at the time of printing.  Dyes can be bleached from paper, but ink washes out with water.  This creates excessive amounts of ink in the mills’ wastewater that must be cleaned from it to comply with federal water quality standards.  The extra time and effort needed to clean the water more thoroughly drives up manufacturing costs for the mill.

Next, old phone books must be kept dry to be recycled.  If a large quantity of directories that has been stacked for recycling gets wet, they begin to decompose, which generates heat.  If enough heat is produced, the stack of books can spontaneously combust!  Because of this fire hazard, many mills will not accept loads of phone books that are wet.  The wet books also weigh more than dry ones, which adds to the cost of transporting them to the manufacturer’s plant.

Next, phone books may contain several types of paper stock.  Some may be coated to give them a glossy finish (like the covers), and they can vary in weight and recycled content.  Notice the difference between the thickness of a directory’s cover and one of the interior pages.  There may also be tabs inside the book that are similar to the cover stock, or glossy pages inside, like magazines.  Paper can be made glossy by a number of means, including supercalendering or coating with clay or varnish.  Depending on what was used, the material can wreak havoc with a mill’s de-inking process.  Sometimes, a certain type of coating is desired by the mill -- clay can actually help to de-ink paper and make the resulting fiber brighter!

Finally, the supply of phone books in any one area tends to be seasonal.  Paper mills require a steady flow of fiber because a paper machine operates 24 hours a day; shutting it down is a complicated process.  An average paper machine can produce 3,000 – 5,000 feet per minute of paper, requiring several tons of feedstock per day.  While there are phone books being delivered somewhere all year round, they are usually only delivered to a particular community at one time of the year.  The transportation costs to get recovered phone books from another city to a mill far away may be too high when there are alternative grades of paper that are available from closer sources.  This is especially true when the other challenges involved in the re-pulping of old phone books are considered.

All of these factors conspire to make OTD one of the lowest-priced grades of recycled paper.  While this isn’t good news for the recycling companies who sell the recovered books, it can be good news for mills in search of cost-effective raw materials.  Knowing what they’ve got helps a mill to match its washing and de-inking process to achieve optimal results.

 The information included in this handout was gathered from a variety of sources, including BellSouth, the American Forest & Paper Association (AF&PA), the U.S. Environmental Protection Agency (EPA), Daishowa’s Papermaking Seminar, Conservatree, E Magazine, BioCycle magazine, the Technical Association for the Pulp and Paper Industry (TAPPI), the Association of Science-Technology Centers Inc., the Institute of Scrap Recycling Industries (ISRI), the Smithsonian Institution, and Bauer Bros.