23 February 2014
The Manufacture of Printer Ink Cartridges: Materials
Although printer ink cartridges and printer inks are used daily in an environment like UC Davis, not many students would think to examine the raw materials that are used in ink cartridge design, nor how the manufacture of such a product affects the environment. The design of these cartridges, which are so essential in a college student’s day-to-day life, is actually a very complex process and involves numerous components and chemical processes. Printer cartridges differ across companies in a number of ways, like whether they use printer ink (waterproof and light-fast) or dye ink (which is soluble in water) (Production of Inkjet Cartridges), and in the construction of the cartridge itself. Printer ink cartridges are made from a variety of plastic mixtures and micro-engineered electronics, and thus make it challenging to dispose of them in an environmentally-conscious way – however, this paper will give some insight into the material contents of printer ink cartridges and print ink, as well as the processes used in the retrieval of needed raw materials.
Typically, printer ink cartridges are made of two main components – the body of the cartridge that acts as a container for the ink (as well as the hydrophobic foam, along with the ink, inside), and the printhead that transfers the ink onto paper during the printing process. However, some models of ink cartridges can be bought without the printhead, if the cartridge and printhead are designed to be used separately, resulting in a cheaper purchasing price. A printhead is comprised of four main parts: the nozzle plate where ink is ejected onto paper during printing, the cover plate that shields the nozzles, the common ink chamber where ink is housed immediately before printing, and (in piezoelectric printers) the PZT substrate which houses a piezoelectric crystal (Technology Overview-Technology-Inkjet Print Head). The piezoelectric crystal vibrates within the body of the cartridges to cause the stream of ink ejected from the nozzles to break into droplets at regular intervals. “PZT is composed of two physical elements composed of the two chemical elements lead and zirconium combined with the chemical compound titanate. PZT is formed under extremely high temperatures. The particulates are filtered out using a mechanical filter” (What is "PZT"?). As piezoelectric crystals require a lab or factory setting (as PZT is formed under temperatures not found in the natural world, as well as from separate chemical compounds), PZT crystals don’t have a country of origin and can be produced in any locality that has the required technology.
In printers that use a thermal inkjet/ink cartridge, each partition of the ink reservoir houses a heating element that has a metal plate or resistor – after a signal given by the printer, a weak electric current flows through these, and the ink in contact with the “heated plate is vaporized into a tiny air bubble inside the nozzle. As a consequence, the total volume of the ink exceeds that of the nozzle…an ink droplet is forced out of the cartridge nozzle onto the paper” (All about Ink Cartridges for Printers). Although I was unable to discern the exact contents of the metallic plate, I believe that it is probably manufactured out of steel, considering that steel is used in almost all of the metal parts of ink cartridges. The most common type of resistor, which is likely found in most thermal ink cartridges, is “the molded-composition resistor, usually referred to as the carbon resistor” (Resistors). These types of resistors are primarily composed of carbon, hence the name. Additionally, carbon-film resistors “have a…coating of resistive material on a ceramic insulator” (Resistors).
The amount of nozzles in the printheads of ink cartridges varies across brands, but newer models of cartridges tend to have more nozzles. “Tektronix (352 nozzle) and Sharp (48 nozzle) printheads are made with all stainless steel jet stacks. These jet stacks consist of multiple photochemical machined stainless steel plates bonded or brazed together at a high temperature” (Le). There are three central raw materials used in the production of steel: iron ore and coking coal are the two main inputs, and scrap is used (mainly) in EAF (electric arc furnace) but also in BOF (basic oxygen steelmaking) steel. There are nine other metals found in steel to a lesser degree – most all types of steel have trace amounts of manganese (used as an alloying element for strength and desulpherising) and silicon (for de-oxidation), and some steels have some quantity of nickel (for anti-corrosion), chromium (for resistance to temperature, general wear, and corrosion), zinc (for galvanization), and tin (for the creation of a protective coating). Minor allying elements that can also be found in some steel types are molybdenum (for weldability as well as resistance to heat and corrosion), vanadium (for hardness), and tungsten (also for hardness) (Steelmaking Raw Materials). Steel is important to the manufacture of ink cartridges not just an essential “ingredient” of the cartridges, but it also plays a major part in the extraction for the raw materials used in plastic-making. All crude oils used in the manufacture of “feedstocks for plastics are extracted and transported and refined by machines made of steel, as well as the casts and injection machines used in the moulding of plastic parts” (Smil 38). Some ink cartridges (including the commonly-found HP brand ink cartridges) also contain precious metals like gold or palladium (Fagan).
Many ink cartridges, across a wide variety of brands, contain a spongy material called hydrophobic foam. HP-brand hydrophobic foam is made of a synthetic, porous rubber and contains water-repelling agents. Other competing brands of ink cartridges house a reservoir containing “unfelted polyurethane open cell foam” (Braga). The foam is used to hold the ink and at the same time repel outside water or humidity in the air, which can cause problems for the cartridge’s functioning and the delicate chemistry of the printer ink (Brown). The main raw materials used in the production of polyurethane foam are polyol (obtained from propylene and/or ethyl oxide), isocyanate (a highly reactive substance that bonds to the other components and determines the rigidity of the foam), and water (which acts as a blowing agent) (What is Polyurethane Foam?). Polyurethane foam is made in either a laboratory or factory-setting, in which all 3 raw materials are mixed along with a catalyst and stabilizer. After nucleation starts, and the reaction begins, and the cells of the mixture start to foam – the final result of this reaction is the hydropohobic foam used in ink cartridge production.
Coal is a vital raw material used in the production of steel, as well as for the use of printer ink cartridges, because of electricity – the power source used in printing. Coal is a fossil fuel, and so is limited in supply, and its continued use is detrimental to the environment, biosphere, and atmosphere. Coal is found in naturally-occuring deposits or in coal fields. “Coal reserves are available in almost every country worldwide. The biggest reserves are in the USA, Russia, China and India…the location, size and characteristics of most countries' coal resources are quite well known. What tends to vary much more…is the level classified as proved recoverable reserves [that are] economically and technically extractable” (Where is Coal Found?). The main raw material used in the transportation of various printer ink cartridge components, as well is in the distribution of printer ink and ink cartridges, is also a fossil fuel: oil. Oil is much less widely distributed than coal, and its main reserves are concentrated on the Eurasian continent as well as in Canada (Top Ten Oil Reserves). While oil is a vital raw material for transportation and distribution purposes, electricity is needed for intended use of ink and ink cartridges – printing. Electricity is a secondary energy source derived mostly from coal-burning, so the use and reuse of cartridges is dependent on the raw materials of coal and oil. This poses a number of problems for environmentally-conscious printing companies, as the burning of coal and oil for energy releases greenhouse gases into the environment and contributes to global warming and climate change.
The casing in which the ink is housed is the second main component of the printer ink cartridge (while the other is the printhead). This casing is made out of a plastic that’s an engineering-grade polymer which has a very slow decomposing rate – between 450 to 1000 years depending on the cartridge (Environmental Benefits: Reuse & Recycling Ink and Toner Cartridges). There is a variety of engineering plastics on the market, and although I couldn’t discern the exact type of plastic used in the construction of ink cartridges, most plastics share the same basic preparation process. The main types of raw materials used in the production of plastics are usually fossil fuels, like crude oil and natural gas (although some “greener” options have been devised, like soy and hemp). These compounds contain hydrocarbons, which change into monomers – the end product that is processed into plastic – after chemical treating. “Once the monomers are extracted, they have to be chemically treated to make them bond together and form long polymer chains. This is normally done either through polymerization or polycondensation” (How is Plastic Made?).
The final component of printer ink cartridges is the ink itself. The primary raw materials used in the production of printer inks are additives, solvents, pigments, and binders. Pigments serve to color the ink, but also provide a glossy sheen to the printed word as well as resistance to heat and light. There is a wide variety of pigments on the market, most of which are made or mined in China and/or India, such as “acrylics, energy cure resins, carbon black, titanium dioxide, nitrocellulose, phthalocyanine pigments and Violet 23 pigments” ( Savastano). Binders and typically composed of resins, and bind the different chemical components of the ink together – while also binding the ink to the paper during printing. Some commonly used resins are acrylics, alkyds, rubber resins, and ketones (Wansbrough). Solvents keep printer ink liquid until it is applied to the paper, when it separates to allow the ink to dry. Solvents are comprised of various man-made chemical components, such as ethyl acetate and isopropanol (these are “volatile” solvents, which are used in printing processes that require the solvent to evaporate/separate rapidly). The final primary raw material used in printer ink is the additive. There are many types of additives used in ink production. The most commonly used additives in ink production are a plasticizers (an example being dibutyl phthalate), waxes (example: carnauba, which is extracted from the leaves of the carnauba palm), driers (salts or soaps of manganese, zirconium, or cobalt), chelating agents (aluminum chelate and titanium chelate), antioxidants (eugenol), surfactants, alkalis (monoethanolamine), and defoamers (hydrocarbon emulsions) (Wansbrough).
Printer ink cartridges ready for recycling are sent in by customers or business partners to a cartridge recycling center – for brevity, I will describe the recycling of HP printer ink cartridges, a major global brand. HP ink cartridges are disassembled in a recycling center in Smyrna, Tennessee, where ink cartridges are sorted and prepared for disassembly. Any remaining ink is drained out of the cartridges, while any foam containing ink is removed and disposed of. Unfortunately, there are no current methods in place for the recycling of the ink or the hydrophobic foam used in printer ink cartridges. This means that these become waste products during the recycling process, and so are destined to end up in a landfill. Any precious metals, such as gold or palladium, are separated and sent to a different facility to be melted down. The plastic is then washed and shredded into pellets of resin and sent to another factory, owned by the Laverne Group Inc., outside of Montreal, Quebec (Fagan). This process requires the use of heavy machinery and melting technology, which obviously uses a great deal of raw materials in the form of fossil fuels for energy. The shredded plastic then goes into a large mixer along with special additives. It’s mixed for several hours and is separated into 20-ton batches, then heads off into an extruder, which is heated to 575 degrees Fahrenheit. The plastic is melted and forced through small nozzles, creating long strands of plastic referred to as “plastic spaghetti.” The next raw material used in the recycling process is water, which the plastic strands are run through to cool them down. The strands are crushed and sent through a de-materializer up to four times, to ensure that there are no remaining particles of additional residue, other than plastic, in the mixture. Once this is complete, some plastic from each batch produced is run through an injection molding machine and tested for quality – and if the results are satisfactory, than the plastic batch will be used to make re-manufactured ink cartridges ready to enter the market (Greiner).
Ink cartridges are complex devices – and their production reflects that complexity, as it involves a great deal of acquisition/production of raw materials, as well as processing, machining, and chemical reactions. Many materials that are used in the manufacture of ink cartridges are synthetic in nature, and so are challenging to trace back to base raw materials (materials retrieved directly from the earth). However, many individual components of printer ink cartridges, such as the hydrophobic foam, plastic casing, printhead, and ink involve the use and transportation of fossil fuels like coal and oil. This makes it important to learn how the use of ink cartridges affects the environment – and considering the heavy fossil fuel use in the production, distribution, and transportation of printer ink cartridges, its effect is considerable. However, some steps are being taken in order to increase the recyclability and reuse of printer ink cartridges, such as HP’s plan to incorporate multiple sources of recycled plastics, including plastic water bottles, in the plastic components of HP printer ink cartridges (HP Innovates “Closed Loop” Inkjet Cartridge Recycling Program, Gives Plastic Water Bottles Second Life). Other printing companies, like the Pelikan Ink Company, are committed to developing environmentally-conscious printing techniques and reducing printing’s effect on the environment.
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13 March 2013
Printer Cartridges: Energy Consumption
While information is becoming increasingly available in the digital form, there is still a great demand to reproduce printed media. Printers are annually being sold in the billions and along with that are printer cartridges (IDC Worldwide). Except, unlike printers, cartridges are meant to be replaced regularly For this reason it is important to evaluate the impact print cartridges have on the environment, mostly in the area specifically in energy consumption.
Just as there are a multitude of different types of printers, there are even more different types of printer ink that is used for cartridges. Focusing mainly on inkjet printer, there are two types of liquid ink –pigment-based and dye-based. Within these categories are waterproof and solid inks that haven grown increasingly popular. Light-fast ink are one of the newest technologies which stems from pigment-based inks. Within these categories are a variety of specific uses –such as light-fast ink being meant to not fade easily under the sunlight; typically used for outdoor advertising— yet, the basic materials that go into the products are incredibly similar.
Now, just based on the types of ink, solid ink is cited by the EPA to have less energy consumption than similar laser print over its life cycle. This stems from the fact that solid ink has smaller packaging, transport and CRU environmental impacts since it doesn't require a cartridge to house the ink. Color laser has well distributed energy consumption except for the costumer replaceable units, which in the long run makes it less favorable than solid ink. According to the EuPIA, Water-based inks tend to use significantly more energy than solid inks, mostly when used on plastic or metal substrates. For this reason, we will be focusing on water-based non-solid inks for they are cited to be more of an environmental issue.
There are four basic raw materials that are used nearly universally among all printer inks: additives, solvents, pigments and binders. Then, from within these divisions are a multitude of possible ingridients –just for additives, a manufacture could choose anything from plasticizer (dibutyl phthalate), wax (carnauba), dier (salts, zirconium, or cobalt), chelating agent (aluminum chelate and titanium chelate), antioxidant (eugenol), surfactnats, alkali (monoethanolamine) and defoamer (hydrocarbon emulsions). The reason being is that each ink manufacture has their own standard of viscosity, the material's stickiness, and range of colors. This creates a huge problem in trying to gauge the amount of energy consumed in simply transporting the raw materials to ink manufacturing plants. Transportation energy use in this stage of the process will be lacking; however, to give an idea of where these raw materials come and go I have the following statistic: nearly 60 percent of all ink facilities and 75 percent of all persons employed by ink facilities are located in ozone nonattainment areas and in population centers (EPA 33). In other words, even though nonattainment areas are zones that have poor air quality, there are ink facilities that are by population centers. As such, transport of the finished product to consumer use would be less significant than the shipping required for raw materials to come to the ink facilities. Now, for further context of the necessary shipping needs for raw materials, the United States EPA stated that “according to the 1987 Census, lithographic ink accounts for almost 40 percent of ink shipments in the United States and slightly over 40 percent of product shipment value” (EPA 33). Shipping costs are significant and the sector of ink production that the essay is dealing with has nearly 40 percent share of total ink shipping costs. Unfortunately, the survey did not include any examples of where the materials come from nor where exactly do these products tend to be headed.
Returning to the ink itself, according to the EuPIA, the manufacture of ink is not regarded as an energy-intensive sector (EuPIA). Even more, they cite this as the reason why ink manufacturing is not included in any national or EU energy management initiatives. Yet, ink facilities published studies comparing different processes in ink mixtures to determine which was most energy-cost effective. Before entering that discussion, it is important to introduce varnishes as an important aspect of ink production.
A varnish is a mixture of solvent, resin and additives –pigments are later on mixed with a varnish. There are two main types of varnishes: oleoresinous varnish and non-oleoresinous varnish. Oleoresinous varnish, contains drying oil, is cited by Heather Wansbrough as being more energy consuming due to the need for much higher temperatures in much more rigorous conditions than non-oleoresinous varnishes. Yet, when trying to research exactly how much energy is being consumed there wasn't much available to determine the quantity. Nonetheless, the fact that multiple sources do cite as closed and open kettles, the machinery necessary to mix oleoresinous varnishes, as energy intensive supports the notion that it is energy consuming.
To give an idea of the amount of energy goes into the procedure, Wansbrough refers that the process may involve temperatures ranging from 120°C to 260°C for anywhere from a few minutes to several hours. On top of that, it is also cited by the EPA that closed kettles can prepare up to thousands of gallons of ink at a time. Unfortunately, even if it was secured how much time a certain manufacturer used to raise their 1,000 gallon product up to a certain degree it is not feasible to calculate the energy used because it is extremely difficult to retrieve the specific formula that manufacturers use for their ink.
Now, non-oleresinous varnishes had more resources to guage the energy consumption than their counter-part. These varnishes are made up of simple resin solutions that do not require nearly as much heat to create a reaction; as such, they are considered less energy consuming. There are several methods to mix varnishes with the manufacturer's chosen pigments, but the two most popular are cavitation mixers and rotor/stator mixers. For rotor/stator mixers there are still two more divisions: dip and bake system, and chemically cured trickle system. Comparing these two divisions shows how significant heat use is –dip and bake system consists of a monorail conveyor conveying 4 stators per hanger through a pre-heat oven, then a varnish dip tank and finally to a cure oven (Lawrence). As an example of what these parameters consist of:
Meanwhile, the trickle system does not require a cure oven, only a pre-heat oven that is still well below the temperature settings that a dip and bake system needs. For this reason, the following shows how a dip and a bake system compares to a trickle system:
Even when the trickle system was pushed to a 100 to 3 ratio, it consistently did better than the dip and bake system.
After the varnish has been mixed with the pigment manufactures encounter an issue where the pigment particles clump together. There are three equipment types to do the task: three rolls mills, bead mills and cavitation mixers. Unlike the comparison between the dip and bake, and trickle system, there was little comparison between the systems that was discovered. Instead, each system will be included with information that was provided that gave an idea of the energy consumption.
Three roll mills are a series of cambered rollers rotating in opposite directions, they are fed pigment particles through a hopper so to disperse the particles by the sheer force of the rollers. The roll pressure, speed ratios and temperature must be carefully controlled and monitored. The machinery must be water cooled to reduce the build up of frictional heat.
Bead mills consists of a cylindrical chamber filled with beads while the actual machinery is surrounded by a water jacket for cooling. Ink is pumped into the chamber and the beads (referred to as the “charge”) set in motion by a series of spinning discs or pins. The charge grinds the ink, breaking up the pigment clumps and evenly dispersing the ink. The ink flows out of the chamber through a sieve and the charge remains behind to be re-used. Bead size depends on the viscosity and rheology of the ink.
Three roll mills and bead mills both have an issue of creating frictional heat that show how much energy is being continuously lost in the process. According to Wansbrough, cavitation mixers are cited to be efficient at dispersing certain pigments and allowing predispersion of a number of others. They do not have the same heat issues as found in the other processes.
Shipping was discussed before hand, thus we will be transitioning to plastic that is used to create the cartridge. Unfortunately, plastics were difficult to analyze due to the lack of studies found. Instead, studies done on recycling the plastics were plentiful –which isn't covered nearly as much for energy usage.
Common issues with recylcing plastic stems from the fact that recycled plastics are not nearly usable as virgin polymer; however, recently HP has created a plastic, PET, that can be recycled to the point that 50% can be used again in a closed-loop procedure. In terms of energy, this means energy used for shipping is saved, but relocated to recycling efforts. The studies and articles refering to this new procedure do not mention energy savings.
However the EPA did mention there is some energy recovery through combustion. Printed manner, due to intrinsic calorific content, can be incinerated in plants with energy recovery. Downside is that plastic based packaging needs collection and sorting. When trying to research exactly how much energy is being released through combustion there was nothing conclusive. The studies are either far too old or simply nothing concrete –stating it's energy efficient but nothing more.
Overall, the EuPIA does not consider the ink manufacture process as energy-intensive and for this there is a lack of studies down in the manufacture process of inks. Methods of varnish mixture were from companies that were promoting their product which may have a conflict of interest. Nonetheless, recycle efforts need to be more clear in what ways they are environmentally friendly –they may be saving the raw material, but not mentioning anything about energy consumption is troubling.
EPA. Office of AirQuality. CONTROL OF VOC EMISSIONS FROM INK AND PAINT MANUFACTURING PROCESSES. N.p., 1992. Web.
EuPIA. ENVIRONMENTAL IMPACT OF PRINTING INKS. Rep. British Coatings Federation, Mar. 2013. Web. 13 Mar. 2014.
IDC Worldwide. "Ink Jet / Laser Computer Printer Sales Statistics." Statistic Brain RSS. N.p., 2014. Web. 13 Mar. 2014.
Lawrence, Bill. "Energy Consumption of Varnishing Processes, a Cost Perspective." IEEE Xplore. Oven Systems Inc., n.d. Web. 13 Mar. 2014.
Wansbrough, Heather. "PRINTING INK TECHNOLOGY AND MANUFACTURE." Nzic.org. N.p., n.d. Web. 13 Mar. 2014.
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Life Cycle Analysis of the Waste, Byproducts and Environmental Impact
of an Average Printer Cartridge
Printer cartridges have been referred to has the disposable electronics of our generation. Without very much imagination, one can see that an ink cartridge was meant to be discarded after a short amount of time, so it would be logical to think that the processes involved with making them were cheap, recyclable or at least decomposable. As I researched I found this not always to be the case. Although processes must vary in the way they are made from different manufacturers, and none of them are particularly interested in publishing the processes and materials with which they make them. This makes an analysis on the wastes and byproducts difficult to do, as what could have been a precise process of the exact chemicals used is now forced to be a generalized summary of common methods of producing similar materials. The other side of the spectrum is the amount of the materials that are involved in making an ink cartridge. Because of the sheer volume of them, listing them all and the byproducts that are involved would be close to impossible. Therefor I’ve chosen to focus on the largest outputs involved. The parts of a cartridge this report will cover are the plastic body, the printhead, hydrophobic foam, and the inks themselves.
The nozzle plate and the resistors in a cartridge is part of the inkhead and is made of stainless steel. Stainless steel is a combination of iron ore mixed with chromium and nickel and processed using limestone and coal. The main ingredient, iron, is used heavily around the world, and 2/3 of the coal mined comes from Australia and Brazil. The effect of mining these have detrimental effects on the landscape in terms of using up natural resources, as well as contributing to air and noise pollution. Extracting iron for steel is also one of the most wasteful processes in terms of producing slag (composed primarily of calcium silicate and calcium phosphate), which is the inorganic material left over after the refining process. Not everybody see this as waste though- slag can be used to make asphalt and gravel among other resources both from the initial refining in the blast furnace and again when the iron is further refined into steel. This has a huge impact on lowering CO2 emissions, as byproducts from steel making can be used locally instead of having to import these same products. The refining process also gives off large amounts of carbon dioxide, carbon monoxide and calcium silicate as coal (a carbon source) is burnt and interacts with oxygen. Carbon dioxide is of concern as it is the main cause of global warming. Carbon monoxide is a poisonous gas, and if not properly ventilated is deadly. It is also a contributor to greenhouse gas effects, and while it disperses quickly is generally harmful to the environment. In industrial areas the level of carbon monoxide is often elevated, which can cause issues to humans and other animals in the area. It is especially dangerous to pregnant females, and leads to lowered birth expectancies. When iron is refined to steel magnesium powder is added to react with and remove the sulfur in the iron. This creates magnesium sulfide, which is poisonous and if it makes it to the water system will cause acid rain. The magnesium itself is generally harmless and disperses quickly in air. The chromium which is added to steel to make it non corrosive, but it is also chronically toxic to marine life (studies on mammals and birds have not been reported). Chromium is released into the air but particulates settle within 10 days, sticking to the soil or sediments on land or in water. Nickel is similar to chromium in the way it disperses. They are both released into the air and are carried to the sediments. While both chromium and nickel are highly toxic to marine life, there seems to be little effect on humans besides an irritation or allergy. It is actually thought that mammals require small amounts of nickel in order to obtain proper growth. Steel is great resource to recycle, as it can be mixed with more iron and virtually all of the material can be reused.
Also in the printhead is the PZT substrate. The materials it is composed of are zinc and lead. One of the byproducts of zinc extraction and processing is sulfuric acid, which is a highly corrosive material that burns plants and animals upon contact. It has been studied in marine life, and been shown to have acute toxicity (meaning its effects are rapid). Zinc is released into the air during manufacturing of PZT, and generally settles to the soil and water after rain. It is toxic to plants, and when there is too much zinc in the soil it will cause them to die. However it is does not build up in the plants, so scientists assume that eating plants that manage to live in zinc-heavy soil should be fine. It does build up in fish. Marine life is highly susceptible to zinc poisoning, and can result in long and short term effects. As with many compounds, studies of zinc in mammals and birds have not been properly done as its more difficult to tell how much they’ve actually been exposed. However many studies have been done regarding lead in humans, mammals, birds and fish. Lead has been shown to be extremely bioaccumulative in all living tissue studied. It is a carcinogen, reduces lifespan, causes reproductive problems and lowers fertility. It has also been known to causes behavior and appearances to change. Because lead is so toxic, and before studies had been done it was used in almost everything, detailed studies have been done in the toxicity of lead to children. Children under the age of six are especially sensitive to lead, and overexposure can cause damage to the brain and nervous system, hyperactivity, developmental delays, hearing loss and even death.
The most noticeable part of the ink cartridge is the plastic body it is enclosed in. Plastic is made from crude oil byproducts and are divided into seven different types. While it is hard to determine what type of plastic is being used to produce the cartridge body, a recent announcement by HP saying they will be using recycled water bottles to make their cartridges indicates it is either a high density polyethylene (as water bottles are) or a mixture of different plastics. High density polyethylene (HDPE) is known for being heat and water resistant, both of which are needed in the printing process. Plastic is made from crude oils byproducts, which extracted primarily because of the huge levels of energy stored in the hydrocarbons. A distillation column is used in this process, separating the oil by the number of carbons it contains at different states. The lightest hydrocarbons are petroleum gas, which are the ones used to make plastics. The process of breaking larger hydrocarbons down into smaller one is called cracking, and requires extremely high temperatures (up to 1500 degrees fahrenheit). This step is interesting, because the petroleum gas distilled here is actually a byproduct of the oil refining process. From here the monomers are processed into polymers using a series of processes. From here the cartridge is shipped, a process that gives off large amounts of CO2. The average piece of plastic in 2012 was shipped 521 miles from where it was originally created. HDPE is one of the most readily recyclable plastics, which sadly still only means about 15% of it can be recycled. HP and several other companies have taken to making their cartridges with as much as 50% recycled plastics, which significantly reduces the materials needed. Even with 15% of HDPE being recycled, almost 4 million tons of it get thrown out in the US a year. Because plastic is not decomposable, any that is not recycled is generally stored in a landfill or burnt, where the main concern is the amount of CO2 released. HDPE is 86% carbon, and 98% of that carbon is released as CO2 in the atmosphere. Plastics that aren’t burnt don’t decompose often end up in the environment and are harmful to the wildlife.
The next part of the cartridge to discuss is the hydrophobic, or polyurethane foam. Polyurethane is made of polyols and diisocyanate. Polyol is an alcohol and a plastic, so the processing and making of it is similar to that of the plastic cartridge above. It is is originally made from soybeans or castor beans or crude oil byproducts. Farming is thought to be relatively green, in the sense that plants are natural and renewable. There is a discrepancy, however, in the amount of farming done for sustenance compared to the amount needed for energy (fuel vs. food debate). Nitrous oxide is a byproduct of the farming industry, and is produced in the natural process of decomposition. This happens at an accelerated rate in the fertilizer used on the soybeans. Nitrous oxide is 298 times more harmful of a greenhouse gas than carbon dioxide. Isocyanates are the second ingredient in polyurethane. The traditional fossil fuel version of polyol has been shown to cause convulsions, vomiting and affect the nervous system when swallowed. This could have potential implications to marine life, however I was unable to find research on this. Exposure to isocyanates has been shown to be the leading cause of occupational asthma, both from inhalation and dermal exposure. There is very little regulation on isocyanates. In 1984, Bhopal, India had a leak of gaseous isocyanate and the effects of that on the workers have been studied. Over 2,000 people died and almost 200,000 cases of blindness, liver and kidney infection, respiratory tract and lung damage among other things. Despite the obvious dangers of this chemical, there is a lack of regulation and an overall lack of transparency in companies about where and how they are processing these chemicals. The processing of isocyanates and polyol into polyurethane produces CO2, which is thought to be the major contributor of global climate change. Perhaps even more frightening is the wide use of polyurethane, used in everyday items including baby mattresses. It has been shown that when not created properly, polyurethane can have the same effects as the isocyanates in it.
Inks can be broken down into four components- additives, solvents, pigments and binders. Because of the sheer amount of chemicals used in this process, I will briefly discuss as many as possible in the next paragraphs.
An additive is put in ink to give that ink a certain property or function. Dibutyl phthalate is a plasticizer and is composed phthalic anhydride and n-butanol in the presence of sulfuric acid (PZT byproduct). Phthalic anhydride occurs naturally in the environment and has not been shown to be dangerous to the environment. N-butanol has also not been shown to be harmful, and is in relatively high levels in some states, such as Michigan, Florida and Ohio. The production of N-butanol releases isobutanol, a solvent, which is safer than N-butanol. Within 28 days n-butanol biodegrades in the environment after being released as a gas. Another additive is zirconium, which is used as a dryer. Zirconium is an element found primarily in South America and Australia, but is not naturally found in a pure form so there is a lot of processing that must occur in order to process it. The byproducts from this process are silicate, ilmenite, and rutile which are all natural ingredients in sand. They are typically dumped back into water at the site they were originally extracted from, and don’t have noticeable environmental effect. However because zirconium is hard to find in large quantities, the environmental cost of transportation produces high levels of CO2. Cobalt is another element used as a dryer, and is extracted hand-in-hand with copper. These materials are found in Africa along what is called the copperbelt. One study in Zambia looked at the impact mining had on the environment and community. They found deteriorated water quality, vast slag dumps and air pollution which affects the mammal, marine and vegetative life.
Ethyl acetate is a solvent produced by combining ethanol and acetic acid. Ethanol for commercial processes is generally made from corn, and producing it results in carbon dioxide. Acetic acid generally enters the environment through water waste and is broken down in the air by sunlight. High concentrations have been shown to be harmful to plants, animals and marine life. It is generally released in a liquid form, but quickly evaporates, which is a large contributor of smog in areas of production. Ethyl acetate is able to pass through human skin, and has health risks in humans, and prolonged exposure can cause damage to internal organs such as the kidney, lungs, liver or heart.
Pigments are the defining color of the cartridge. Carbon black is often made from shredded tires or other rubber. It is simply a crystallized form of carbon. The production of carbon black produces carbon disulfide, carbonyl sulfide and hydrogen cyanide. Carbon disulfide is dangerous to humans, but as it evaporates quickly into the atmosphere most of these effects should only occur in the workplace. It can settle as a temporary fog and destroy any vegetation present.Hydrogen cyanide is a chemical deemed safe to humans, as we are regularly exposed to it from indigestion and in cigarette smoke (which are not the safest things). The main componant of nitrocellulose is nitrogen used as an oxidizing agent. Unfortionately it is also released into the environment later, and if levels get to high the consequences are dangerous.
While I will be printing this report using printer ink, doing this research has made me extremely wary of the consequences of printer cartridges in the environment. The chemical outputs I was able to find seem unnecessarily harmful, and the complete lack of transparency makes me consider how bad the actual effects of a printer life cycle might be.
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