Cardboard Raw Materials Research
The question is what goes into making cardboard. The ingredients for a product that goes through manufacturing are called “raw materials”, and where they are collected is the topic of this paper. The cardboard in question initially was the material used for the packaging of Apple products such as the iPod, iPhone, and Macbook. However we, as a group, were faced with very little free information regarding Apple’s materials and resources use. The group agreed to broaden the topic to allow for a wider breadth of information. Cardboard in general was much wider of a topic, and used in all types of packaging. The majority of this text will delve into the preliminary stages of cardboard manufacturing, including the raw materials and the processing involved.
To understand the impact of cardboard on our environment, society, and economy, one must first understand the scale of its production. Boxes made of corrugated cardboard are found in all sorts of places in society. One can find cardboard used for packaging in the stockrooms of retail spaces, supermarkets, shopping malls, and schools. The versatility of corrugated cardboard led to increased manufacturing of it and widespread use as packaging and display products. “During 1992, more than 25 million tons of corrugated cardboard were produced in the United States. Another 6 million tons of non-corrugated box board or paperboard were also produced for use in folding cartons.” What separates corrugated cardboard from other cardboard is that it made of three layers of brown kraft paper, giving it its unique stiff, strong, and light-weight quality. “In 1884, Swedish chemist, Carl F. Dahl, developed a process for pulping wood chips into a strong paper that resists tearing, splitting, and bursting.” This unique pulping process was called the “kraft process” from the German word “kraft” meaning strong, a term coined by Dahl.
The cardboard manufacturing process is relatively inexpensive. Compared to plastics and metals, cardboard packaging is superior financially because the production process is far more time efficient. In the kraft paper making process, the tree trunks are torn into small pieces and then those pieces are put into a batch digester. The transition from lumber to wood fiber(cellulose) is depicted in Figure 2. This great industrial sized machine is called a batch digester because it literally breaks the wood chips into a pulp using a similar process found in our own digestion system. “The batch digester is a high pressure tank that dissolved the lignin, which binds the wood fibers”. To jump ahead to waste and emissions phase of the embodied energy calculation is inevitable, waste is produced in almost every step of production; the “white and black liquor contained in the process create a corrosion that attacks the internal vessel walls. Carbon steel wastage is the result...” Figure 2 is a picture of a kraft pulp mill, to give a sense of scale. Once the lignin is dissolved, the fibers get sterilized and refined into cellulose. Once the kraft paper is created in the kraft paper mill, it is transported to a corrugating or converting plant. In this plant, the kraft paper is crimped and glued to form corrugated cardboard. The kraft paper is sent to a corrugator machine which is typically “as long as a football field-300 feet (91.44 meters)”. A third of the rolls are used as the corrugating medium and the rest are used as liners, which are the non-corrugated kraft sheets that are glued on each side of the corrugated kraft sheet. The gluing process all takes place in the corrugator as well, where it heats, glues, and presses the kraft paper to finalize the product. The rest is specific to the particular use the corrugated cardboard will be put to, but the cardboard is cut into “wide box banks” that require other machines to print, cut, and paste.
Notice the two emboldened words written in the paragraph above. Trees and glue are essentially the only raw materials for corrugated cardboard. Pine trees are particularly fast-growing and resilient, therefore making the pine tree a most favorable raw materials resource in lumber, paper, and corrugated cardboard production. It is a vertical business model that makes it common for the paper mills to be directly manage the pine tree farms; the largest packaging companies own thousands of acres of land where the trees are matured, harvested and replaced with seedlings. Once the trees have been harvested and stripped of their limbs, the trunks are trucked to a pulp mill. The embodied energy, which will be calculated after the product is completed, must include the energy it takes to complete the harvesting, stripping, and shipping; these processes expend vast amounts of manual energy, chemical energy, and electrical energy primarily. As the business model in the United States is big on profit and vertical integration, the packaging box companies that are larger also own their own kraft pulp mills. According to Art J. Ragauskas of the Institute of Paper Science & Technology presents that paper milling can operate safely and provide for the needs of the daily customer and be profitable by working harmoniously as a single large scale production. The transformation process is remarkable and there are different slight variations to how it occurs, but the primary chemicals are black, white, and green liquor.
White liquor is the fresh pulping liquor for the kraft process containing sodium hydroxide(NaOH), and sodium sulfide(Na2S). Black liquor is “the waste liquor from the kraft pulping process...[it] contains most of the original inorganic components...and a high concentration of dissolved organics”. Green liquor is partially recovered kraft liquor and other residual chemical compounds. It is because of these chemicals that the kraft process is also known as the sulfate process. A great percentage majority, probably 99%, of a sheet of corrugated cardboard is pine wood that has been chemically processed down to cellulosic fibers and then there is an infinitesimal amount of glue used in the corrugator machine where the fiber is formed, pressed, dried, and rolled into wide heavy rolls of kraft paper.
To be stiff and durable, the corrugated cardboard needs an adhesive to keep the three kraft paper sheets together. As mentioned earlier, the glue is applied in the corrugating plant and is usually the final raw material for corrugated cardboard. Corn starch glue is used to bond the corrugated medium to the liner sheets and because of the immense scale of production, the glue must be shipped by truckloads in the form of dry powder. The choice of having the glue in dry powder form is intentional for storage purposes and is stored in huge silos at the corrugating plant. Once drawn from the silo, the powder corn starch is mixed with water and other adhesive chemicals, then it is sent to the corrugator machine. As the glue is pumped in, the corrugator begins to spread the glue onto the corrugated medium and have the liners added on. The cardboard then dries and is packed up for shipping.
Naturally, not all cardboard boxes are made of corrugated cardboard and not all of the corrugated cardboard boxes are just pinewood and corn starch, there are inks and waxes that are also applied for graphic advertisement, safety, and instructional purposes. These other materials are not necessarily listed under raw materials when looking at a regular cardboard box, but when looking at real world uses there are lots of boxes with designs on them. These waxes and inks do not help lower the waste emissions of cardboard production, because they ultimately hinder the recyclability of the product by creating a monstrous hybrid, as expressed in Cradle to Cradle (Braungart and McDonough, 8). Monstrous hybrid is a term coined by Michael Braungart and William McDonough for a product, component, or material that combines both synthetic and organic materials in a way that cannot be easily separated, therefore rendering it unable to be recycled or reused. Most monstrous hybrids can only be thrown out and contribute to the waste stream. Creating monstrous hybrids is hazardous for the environment and even if it can be recycled, it would require a complicated series of steps that require additional energy. Besides wax and cardboard, other monstrous hybrids include foil with paper (i.e gum wrappers), paper with plastic (lamination), and many other poorly designed products. In another sense, having the ink and wax directly on the box is an appealing strategy to avoid more paper and sticker labels, which might seem ecologically beneficial to customers.
The wax used to coat the corrugated cardboard is called paraffin and it is used to make the cardboard water- and grease-resistant for food product packaging. It is a white or colorless soft wax that is flammable, as it is derived from kerosene, and usually mixed with a number of chemicals that can be toxic in large amounts.
Inks are applied as well in some instances to the cardboard to create displays with titles, company names, product descriptions, information, and logos. Graphic designers and salespeople are ultimately responsible for the toxicity and recyclability of their product, mainly because there are high metal-inks among other safer biodegradable options.
The pollution in the pulp mills is extensive since most of them are located near large bodies of water due to previous technologies involving hydro-power and steam. The process of delignification, which is the removal of lignin from wood pulps releases significant amounts of organic material and chemicals into the environment, particularly into rivers or lakes. The waste water runoff can also be a major source of pollution, containing lignin from trees, high biological oxygen demand, and dissolved organic carbon, along with alcohols, chlorates, heavy metals (Reach for Unbleached Foundation). Biological oxygen demand (BOD) is one way ecologists and water treatment specialists can measure pollution, a high BOD is a sign of overpopulation or overgrown-which then leads to decay in large quantities. Dissolved organic carbon is another clear sign of pollution, when there is more waste present than produced by the organisms in the water. The scary fact is that the “pulp and paper industry is one of the largest and most polluting industries in the world; it is the third most polluting industry in North America” (Reach for Unbleached Foundation). There are thousands of varying pulp and paper mills around the world, and specifically there are about 100 kraft mills in the US and the major concern is the chemical and chlorine toxic emissions into water, soil, and air. When something is done in such an imposing scale, there are bound to be drawbacks, but this can be avoided. The Reach for Unbleached Foundation focuses on trying to end the chemical intensive paper making process and foresees, with the industry’s 2.5% annual growth, the negative effects doubling in 28 years. Some pulp mills have effluent treatment plants where their entire objective is to cut down on pollution as much as possible by recycling the waste that is emitted by the pulp mill production.
I found that sources say slightly different things, and statistics are usually all over the place and almost always estimations.
1. “How is Corrugated Cardboard Made?”, http://www.madehow.com/Volume-1/Corrugated-Cardboard.html, 2009
2. Efficient design and resource use in paper and cardboard production, http://www2.lichfielddc.gov.uk/businessguides/doc/guide/0_EE2490_00?section=5, 2009
3. “How is Paraffin Made?” http://www.madehow.com/knowledge/Paraffin.html, 2010
4. “How Cardboard is Manufactured”, http://www.ehow.com/about_6303456_cardboard-manufactured_.html, 2010
5. Slideshow by Cannon Design, http://www.slideshare.net/cannondesign/material-life-the-embodied-energy-of-building-materials
McDonough, et al, Cradle to Cradle: Remaking the Way We Make Things, NY 2008
Johnston, David R; Master, Kim ;“Green Remodeling: Changing the World One Rom at a Time”, Green Biz; http://www.greenbiz.com/news/2011/03/10/recycled-cardboard-good-earth-may-be-bad-health
Art J. Ragauskas
Institute of Paper Science and Technology
Georgia Institute of Technology
Professor Christina Codgell
Design 40 A
11 March 2013
Cardboard: Step 2, The Creation Process
Initially we were intrigued by simply the design aspect of packaging. The one company that seemed to be quite creative with their product packaging was Apple. We went into this assignment with full knowledge that Macintosh is renowned for being extremely protective about every single aspect of their creative process, packaging included. At first, finding information was relatively fast and simple. We were surprised to find a major page that had quit a lot of information under the title, Apple and the Environment. There was even a linked full Facilities Environmental Report; the only downside was that the majority of the information was not for packaging but for the products in and of themselves. It quickly became clear that a large amount of people could care less about the packaging, just what was contained within. Another issue that we hit early one was that we realized that they were only releasing positive aspects. Everything we found spoke about how green and earth friendly their packages were, such as graphs depicting that their natural gas usage had been halved from 2008 to 2011. Once we began to dig dipper it became apparent that much of the information was funneled and there was barely any that would be of us to us in our research of packaging.
Ultimately we decided to scrap Apple all together, making our first steps into the research also our initial failure. From what we had seen however, we began to think about packaging in a more simplistic way. Instead of focusing on a brand that was so flashy and visually impressive with their packaging, we decided to get to the heart material of what makes packaging. Cardboard. This product seems to be the most basic center of the packaging industry and has an immense range when it comes to various types and methods to create. In my portion of the research, I was given the job of determining the specific process of building cardboard. From what I have discovered in my research, there are two schools of cardboard that are important to discuss; cardboard built from raw materials, and cardboard that is built through recycled materials.
The most popular material that is made from raw materials is corrugated cardboard, which is one of the most widely used for a variety of products. What makes up corrugated cardboard in essence is three layers of brown kraft paper, which is a strong paper that is able to withstand what normal paper cannot such as tearing, splitting, and bursting. The main raw material that is utilized to creating this paper is what I had assumed, which is trees. Specifically it is fast-growing pine trees which “are matured, harvested, and replaced with seedlings” (“Corrugated Cardboard” n.p.) by major companies that have thousands of acres of land to grow them. In this sense, making cardboard from trees seems to be a relatively self-sufficient source and isn’t a raw material that is in danger of being used up. Aside from that there are only a few more raw materials that are used to finish the product. Corn starch glue for bonding the corrugated sheets, waxes from paraffin or vegetable oil to create a water resistant liner, and (less of a raw material and more just a component) dies and inks to help brand the packages. (“Corrugated Cardboard” n.p.)
The construction process of making packages is relatively simple and is explained in detail by the website Made How on its article “Corrugated Cardboard”. The process for creating cardboard is divided into five steps: pulping the pine chips, making the kraft paper, shipping and storing the kraft paper, corrugating the cardboard, and finally forming the blanks that are created into finalized boxes.
As stated above the beginning of this process starts with harvesting our natural resource, which are pine trees. What takes place is the method of pulping pine trees via the sulfate process. To summarize what this process is, the trees are initially stripped of their bark, which is then broken down into small chips. From there the chips are placed into a high-pressure tank, which is called a “batch digester” (“Corrugated Cardboard” n.p.) where they are cooked in a solution made of sodium hydroxide. What this process does is dissolve the lignin in the bark, which is the substance that holds wood fibers together. This process in particular is responsible for quite a lot of hazardous by-products such as carbon, sulfur dioxide and nitrous oxides ("Process of Recycling Cardboard" n.p.). These by-products are harmful to the environment and are responsible for issues like acid rain and smog. At the end of this first step pressure is released from the batch digester after several hours and the wooden chips explode into fluffy fibers, which can then move on to the next step, making the kraft paper.
The process of creating kraft paper takes place in a machine known as the Fourdrinier machine, which is in essence a very long conveyer belt with “heat cylinders and felt-covered belts” (“Corrugated Cardboard” n.p.). A sheet of wooden pulp, which is still damp from the pulping process, is fed into the front of the machine, which then pushes the sheet through a wire mesh where the paper is initially formed. The heat cylinders and felt-covered belts are then put into play simply to dry out the paper and collect moisture. Finally the paper exits the machine and is rolled and then ready for shipment.
The shipment process is relatively straightforward. The new rolls of craft paper can be created to a various amount of sizes depending on the customers needs. The most popular sizes are generally sixty-seven or eighty-seven inches wide. The eighty-seven inch rolls can generally weigh up to 6,000 pounds and as many as twenty-two rolls can be loaded onto a single railroad boxcar (“Corrugated Cardboard” n.p.). From there it will be shipped to any number of corrugation plants.
The corrugation plants then separates the paper into different grades, which will be used for the medium and the liner. The combination of medium and liner determine how much strength the package will have. Once a “knowledgeable packaging specialist” (“Corrugated Cardboard” n.p.) speaks with the customer they can get a sense of what type of package the customer desires. Then a product engineer takes that information and combines specific medium and liner in order to build the exact strength of corrugated cardboard packages that fit the customer’s desires.
Finally with all the information given, the plant can begin creation of the corrugated cardboard and the construction of the packages. As stated before, there are two types of cardboard that are made from the kraft paper, the medium and the liner. The liner is standard flat cardboard that we see regularly. The medium is what is placed within liners and is in essence wavy to enhance strength of the cardboard walls of a box.
In order to corrugate the medium, slabs of cardboard that will become the medium are fed into a machine called the “corrugator” (“Corrugated Cardboard” n.p.). The medium goes through two rollers, first the preheating rollers and then into the corrugating rolls. “Steam at 175 to 180 pounds of pressure per square inch (psi) is forced through both sets of rollers, and, as the paper passes through them, temperatures reach 350 to 365 degrees Fahrenheit” (“Corrugated Cardboard” n.p.). While the cardboard is passing through the rollers, massive horizontal flutes come down on top of the cardboard which bends and shapes the it into the medium that will then go in between two liners. The corrugation machines also have different settings on them that allow you to dictate how wide the flutes will shape the medium.
The medium will then travel to what is called a “single-facer glue station” (“Corrugated Cardboard” n.p.) which is a set of rollers that will glue the first liner to the medium. This is where another one of the raw materials comes into play from before, which is the starch glue. The glue is applied to the edges of the medium that will be touching the liner. The liner is then applied and the product proceeds to what is known as the “double-backer glue station” (“Corrugated Cardboard” n.p.) where the other liner is applied in a similar fashion. From here the finished corrugated cardboard piece containing two liners and a medium passes through steam-heated plates, which will cure the glue and fix the pieces together.
Now the final process begins, which is utilizing the blanks, made from the corrugated cardboard pieces that have just been made, and forming them into boxes. At the very end of the corrugator, finished pieces are sliced and cut into equal shapes and then moved to another machine. Here workers prepare a machine with specific inputs for each stack of blanks. This machine is called the “flexographic machine” (“Corrugated Cardboard” n.p.) and is loaded with specific cutters meant for a particular box set. The blanks are fed through the machine where it is “trimmed, printed, cut, scored, and, in a printer-folder-gluer, folded and glued to form a box” (“Corrugated Cardboard” n.p.). Now that the box has been formed it can be ready to be shipped out to the client, or it can go through one more machine known as the “curtain coater” (“Corrugated Cardboard” n.p.) that applies the thin film of a waxy substance to boxes that are made to package fruits, vegetables, or meats.
For the most part this method of creating cardboard boxes seems relatively decent when it comes to sustainable resources. The only natural resource that is in potential danger is the pine tree, but considering major companies method is just to simply by a massive plot of land, harvest the adult trees, and then plant their seeds to create a never ending cycle of trees seems like a strong solution.
My assumption as to the next step to make this process much more environmentally friendly was to simply make kraft paper from recycled materials. By doing this we can completely eradicate the need to constantly re grow and harvest pine trees and also potentially reduce negative emissions that are created during the pulping process.
Upon further research there was a decent amount of articles on the benefits to creating recycled cardboard as apposed to taking it from pine trees; but I also found information that showed a bit more on the negatives to the standard way of creating cardboard than I thought. One of the previous mentioned issues being that during the pulping there is a large release of sulfur dioxide, but there is also the issue that cardboard manufacturing leads to “discharges of effluent into the water supplies surrounding the paper mill” ("How Does Cardboard Pollute?" n.p.). There is also the issue that, even though cardboard is biodegradable, once it is compressed in a landfill it is much more difficult to break down and according to the EPA cardboard and paper products make up for roughly forty percent of the landfills ("How Does Cardboard Pollute?" n.p.). The benefits to recycling help to reduce these issues. One of the main benefits found is that “Recycled cardboard only takes 75 percent of the energy needed to make new cardboard and lessens the emission of sulfur dioxide” ("Facts About Cardboard" n.p.). It would also reduce the amount of cardboard found in landfills, which have issues for the environment all on their own.
The process for making recycled cardboard is generally divided into four steps according to an article published on the livestrong website: sorting, pulping, filtering and de-inking, and finishing ("Process of Recycling Cardboard" n.p.). First the contents are sorted into two types of cardboard, boxboard that is used for things like cereal boxes or juice boxes, and corrugated cardboard which we are already well established with. Once the cardboard is sorted it is soaked in a mixture of water and chemicals, which are designed to break down the fibers to go back to that initial pulp texture that is used to make kraft paper. This pulp is then combined with a smaller about of pulp that has been made from pine tree wood chips, so the pine trees are still required, just not needed is as large of abundance. This new pulp hybrid of new and recycled is put through a series of filters to get rid of any excess non-usable material like the glue used to fuse cardboard pieces together. It is also put into another chemical process, which strips it of any inks or dies that were printed on the original boxes ("Process of Recycling Cardboard" n.p.). Finally the clean pulp can go through the exact same process that regular kraft paper went through.
Ultimately what this entire process shows us is that while creating cardboard out of pine trees is utilizing an ingredient extremely efficiently and is generally avoiding a situation in which the raw material is used it, there is still a major issue concerning the hazardous waste emissions. By simply recycling cardboard boxes that we normally take for granted we can experience massive improvements to our ecosystem.
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"How Does Cardboard Pollute?" LIVESTRONG.COM. N.p., n.d. Web. 13 Mar. 2013.
"How Products Are Made." How Corrugated Cardboard Is Made. N.p., n.d. Web. 13 Mar. 2013.
"How to Recycle Cardboard." Ecolife Recycling -. N.p., n.d. Web. 13 Mar. 2013.
"Process of Recycling Cardboard." LIVESTRONG.COM. N.p., n.d. Web. 13 Mar. 2013.
"Recycling Revisited â life Cycle Comparisons of Global Warming Impact and Total Energy Use of Waste Management Strategies." ScienceDirect.com. Elsevier B.V., n.d. Web. 13 Mar. 2013.