March 13, 2014
Inks used for writing were first produced in Egypt and in China around 2500 B.C.E. The first inks were made from soot and some sort of gum to act as a binder, then mixed with water. As the as the uses for inks evolved so did the inks. In the beginning of the 11th Century, when printing was invented in China the ink used was made from colored earth, plant materials used as pigments, combined with gums to act as a binder. The ink used with the printing press invented by Guttenberg in 1440 used an oil based binder. These rudimentary inks formula are not much different than the inks used today. Today there are two different classes of of inks, writing and printing inks. Inks used today consist of a pigment, a binder, a solvent, and additives. The surface being printed on ultimately determines what type of ink is used. Soy-based inks were developed in 1979 by the American Newspaper Association in response to unstable oil prices. Soy-based inks are manufactured much in the same way the tradition petroleum inks are made, but some of the petroleum is substituted with soybean oil. To be considered a soy-based ink, the final ink formula must contain a minimum percentage of soybean oil. This percentage varies based on the type of ink and ranges from as high as 40 in black news ink to as low 6 in stencil duplicator ink. The exact formulation of the ink is different between manufactures, and largely dependent on the inks use. For the sake of this life cycle materials assessment, a generic soy-based ink formula is used based on the Streamlined LCA of Soy-Based Ink Printing Case Study by the Life Cycle Management Group.
Raw Material Acquisition:
The largest by volume and most prominent ingredient in soy-based inks is soybean oil. This product’s production is the largest and most resource intensive part of soy-based inks. Soybean agriculture in the United States is largely GMO based. For simplicity’s sake this life-cycle assessment will begin with the soybean crop production and not at seed production. Depending on the growing season and location, soybeans are planted from May to July. The land must first be tiled and cultivated to prepare for planting. This involves heavy machinery and herbicides. Soon after planting, as the soybean plants begin to grow they must be sprayed with insecticides and herbicides to insure the young plants are not harmed by insects or weeds. Throughout the growth and maturation of the soybean plant a great amount of water and fertilizers are used. Finally late September when the beans have matured heavy machinery is used to harvest the soybeans. All in all, this process results in the use of 385 pounds of lime, 43 pounds of pesticides and fertilizers, and 700,000 gallons of water, and 5 gallons of fuel for machines to produce a single acre of soybeans. Once the harvesting is complete, the soybeans are than transported to a storage facility and ultimately to a processing plant. A single acre of soybeans produces only 70 gallons of oil.
Soybean processing is completely reliant on gas, diesel, and electricity to operate the various equipment needed to transform soybeans into the ingredients needed for soy-based printing inks. Before processing can begin soybeans must be undergo preparations. First they must be dried, cleaned and dehulled. They are then heat treated and rolled out to form very thin flakes. 99% of oil extraction in the United States relies on a solvent based method. In order to extract the oils from these flakes, they must be soaked in a petroleum based solvent, hexane. Hexane, like most other petroleum based products, comes from the refining of crude oil. The hexane is extracted from the oil and flakes using pressure, heat, and a vacuum. It is also possible to recycle hexane to be used again. The oil and flakes are separated each to be further processed. The flakes are typically ground to form a meal, often used in livestock feeding and the oil must be further treated to produce a crude soybean oil. Water is added to the oil and the water soluble materials can then be separated out of the oils, this is known as water washing. Then the oils must be alkali neutralized through a reaction process. This includes adding usually caustic soda to the oil or sometimes potassium hydroxide and then separating and purifying the oil in a centrifuge. Finally the oil is bleached usually through carbon filtration and deodorized using a vacuum. This pure oil is often further processed to make it more shelf-stable through hydrogenation. This occurs through injecting hydrogen atoms into the triglyceride molecule of the soybean oil. This oil can now be used for the manufacturing of a soy-based ink.
Pigments are responsible for what we see on a printed page. They are the most expensive ingredient in soy-based inks and contribute to about 50% of the cost. Pigments are essentially solid particulate matter that either absorb or scatter light. Pigments retain a crystalline structure and must be evenly distributed throughout the delivery vehicle in order to produce a quality print. There are hundreds of different pigment types used in the production of soy-based inks. Some of these pigments are naturally occurring in the earth as minerals or in vegetables, but most pigments used today are synthetic and are petroleum based. The most commonly used pigment in association with soy-based inks is carbon black. Carbon blacks actually vary greatly in color depending largely on how they are manufactured. Carbon black pigments are petroleum based and in some cases it is a byproduct of other industries. One such example is the tire industry, which produces carbon black through the furnace method. During this process petroleum oil or coal oil is sprayed onto very hot gases which partially combusts resulting in black carbon and tailgas. These two products are separated and the black carbon is compressed and rolled into pellets and is known as furnace black. The final product contains a small percentage of volatiles, or oxidized carbons, but it is almost pure carbon.
Resins are responsible for binding the pigments. They also contribute to the gloss and adhesion of the ink. Like pigment resins can be derived from natural and synthetic sources. Rosin is one example of a natural resin that is obtained from pine trees. In many soy-based inks tall oil, which is a liquid rosin is used. This is a byproduct of the kraft process of wood pulp manufacture. The kraft processes and the production of tall oil is an extremely complex process. Fundamentally, during the cooking process a black liquor is produced. This black liquor is roughly 15% of the desired resin concentration and also contains sodium salts. This black liquor then undergoes several rounds of evaporation and skimming before it can be treated to produce crude tall oil. This treatment includes cooking the concentrated black liquor with sulfuric acid. During the cooking process the black liquor undergoes a chemical reaction turning it from a soap into an oil. Crude tall oil must then be further processed before it can be used in soy-based ink manufacturing. It must be distilled to achieved the desired ratio of resin acids to fatty acids.
Another important ingredient in soy-based inks is a rosin derivative known as maleic resin. It is produced when rosin reacts with maleic anhydride. Maleic anhydride is produced when butane vapors are oxidized. Another common rosin derivative, known as fumarics, uses fumaric acid which is an isomer of maleic acid instead of the maleic anhydride. Many of the formulations for the more commonly used synthetic resins are rather complicated chemical reactions and processes. Among the more commonly used synthetic resins are alkyd resins. Alkyd resins are petroleum based and are in the polyester family. They are produced through estrification of a polyhydric alcohol with a polybasic acid.
Solvents are responsible for keeping the ink in liquid form until the the ink has been laid on the printed surface. Many different types of solvents are used in different formulations and include a solvent and a co-solvent, in order to achieve the desired volatility of the ink. Some solvents are designed to dry relatively slowly through evaporation, while others have high volatility. Another important role solvents play in soy-based inks is their power, meaning how readily do they dissolve the other components of the ink. Solvent are also a huge factor in ink safety. Due to the nature of solvents and the purpose they serve in inks they must be handled with precaution by the users. One group of solvents are hydrocarbon solvents. They are distilled from petroleum and therefore there are various grades with different boiling points for different applications.
Soy-based inks heavily rely on other naturally occurring oils besides soybean to produce the final product. Linen seed oil is one such oil and is a very important solvent. Relatively small amounts of oil are extracted from each seed, usually less than 40% of its weight. This can be done either through chemical extraction, using solvents, or through pressing. Unlike chemical extraction, pressing results in fewer residues and since much of the seed remains it can then be used for animal feed. Pressing works by heating the seed and using either hydraulic pressure or expellers to force the oil out of the seed. Due to the efficiency of chemical extraction, often using hexane like with soybeans, it is often the industry preferred method. Once the oil is extracted it must be alkali refined.The most common method is the acid process. After sulfuric acid is mixed with the crude linen seed oil it rests over night and the refined oil is removed from the top.
The purpose of the reducer in soy-based inks is to produce a clear glossy film over the printed material. In soy-based inks often tung oil is used as tyne reducer. Tung seed is grown in tropical and sub-tropical regions around the world. The nut is encased in a hard shell and must be roasted in order to remove the seed. Once the seed is removed, much like soybean oil, the oil is extracted using solvents.
Waxes are integral to providing soy-based inks with chemical resistance and they also increase rub resistance. Waxes are often melted into the solvent being used. In soy-based inks polyethylene waxes are the most common form of wax. It is a synthetic wax produced from petroleum. It is a form of polyethylene. It is a highly complex production process. Simplified, polyethylene is produced when ethylene gas, is heated under tremendous amounts of pressure and introducing very small amounts of oxygen. This process is known as the polymerization of ethylene gas.
Driers are responsible for the quick oxidation the oils in the soy-based ink formula. Oxidation is essential to the printing process as it turns the ink into a hard film. The soy-based ink industry relies on two different driers, both of which are chemical elements. The first, cobalt, is the most powerful drier, and therefore is favored by the industry. The second is manganese. Due to the complication of the mining and extraction processes, cobalt and manganese production will be omitted from this analysis.
Soy-ink also contains a number of additives to help carry, stabilize, and enhance the final product. One such additive is pentaerythritol. It is in the polyol family and is responsible for carrying the ink. Another is trimethylolpropane, which is made from butane and formaldehyde. Formaldehyde, or methanal, is also used as a stand alone additive. Other additives are used as deodorants and deodorants of the final product. Chemicals are also sometimes used to minimize product foaming and detergents are used depending on the printed surface to allow the inks to better be absorbed.
Manufacturing, processing, and formulation:
The generic soy based ink formula based on Flint Ink and the the Graphic Arts Technical Foundation is: Carbon Black, Cobalt drier, Manganese drier, Polyethylene wax, Tung oil reducer, 100S Type Alkyd, and Varnish consisting of 50% Soybean oil and 50% Phenolic Modified Resin.
Manufacturing and Distribution:
Soy-based inks which are primarily used in large scale industrial printing must also be manufactured in large quantities in a largely automated process. It is important to understand that due to the nature of the carbon pigment there tends to be a great deal of dust generated during the manufacturing of soy-based inks based on the general formulation. In order to avoid this dust and to ensure consistency the process is mechanized. Carbon is moved throughout the manufacturing process using air pressure. Oil is brought to the manufacturing plant in extremely large tankers. There are two general production methods, the first is the large batch system and the other is the continuous system in the large batch system. In the large batch system, the formulation’s ingredients, minus the carbon and half the oil, is added to a mixer. Then the remaining oil along with the proper weight of carbon is added to the mixture. This is done to ensure proper dispersal of the pigment throughout the ink. In the continuous method, carbon in a beaded form is used. The flow of carbon in beaded form can much more easily controlled, therefore the various components of the ink can be added to the mixer and this of course is all automated and is controlled by a computer which analyzes the weight of the ink to determine when to add more of each ingredient. The final product, when mixed, is stored in large tanks and can typically be stored for two months without degradation to the product. The stored ink in the tanking system then will be transferred to various storage vessels before it is distributed. The most commonly used vessel is a 10 to 15kg polyurethane bucket. As most soy-based inks are manufactured outside of the United States it is important to consider the transportation/distribution. Soy-based inks make their way around the world via cargo ships.
In order to maximize profits and reduce their impact on the environment many manufactures of printed material are choosing to reuse paper in their manufacturing process. The paper products must first be de-inked before they can be the reprocessed and made into usable paper. De-inking requires the paper to be treated with an alkali in order to separate the soy-based ink from the paper. Once the ink is separated, it is skimmed off the top of the paper and alkali mixture. This skimmed off material is known as sludge and has no further use in the manufacturing process. Depending on the formulation it must either be buried at a landfill or can burned to produce energy for the paper mill or even used as fertilizer by farmers.
Through this analysis of soy-based inks using a generic formula, it can be seen how many different raw materials, many of which are petroleum based, go into the production of soy-based inks.
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March, 13, 2014
Embodied Energy Analysis of Soy-Based Inks
Design is essentially a facet of every aspect of our lives. The chair you sit on, the clothes you wear, your transportation, the computer you use and even this paper, have all been designed. The role of a designer has been evolving and changing over the last few decades. It has become increasingly important and crucial for designers to become educated and well-versed in the environmental impacts of the products and systems they are trying to change or to create. Soy-based inks have offered a more environmentally friendly alternative to petroleum based inks. An examination, such as this one, is necessary to deduce the processes involved with soy-based inks and the possible benefits to the environment. I conducted research regarding the energy inputs and outputs based on various soy-bean ink use including raw materials extraction, manufacture, distribution, and disassembly/recycling systems.
Boundaries: This report begins with an assessment of the energy processes of the materials, manufacture, distribution and recycling of soy based inks and is followed by a few misconceptions of soy based inks. The exploration of energy-related soy based ink processes for this report required a selection of a soy ink manufacturing formula and I chose to adopt the direction of the Harvard LCA case study, Streamlined LCA of Soy-Based Ink Printing, in their application of recommendations by the Graphic Arts Technical Association and the Sheetfed Research Lab at Flint Ink Corporations. Due to the complexity of the systems involved in each area of this soy based ink assessment, and the gross amount of information, I did not analyze every single life cycle. However, each elemental processes is detailed and important details are further espoused upon.
Energy during Production:
Materials: The generic formula is comprised of: Pigment (Carbon Black), Cobalt drier, polyethylene (PE) wax, Reducer: Tung oil, 100S Type Alkyd, and varnish (50% soy bean oil + 50% Phenolic Modified Rosin Resin).
Pigment: pigments can be either naturally or synthetically derived and are used as a visual identifier for inks. Carbon black inks are composed almost entirely of carbon in relation to the volatiles. The process I chose for the creation of carbon black pigment is the oil-furnace method. During this method, to produce 1 kg of carbon black, the utilization of energy is ranged at (9-16) x 10 to the seventh power J. Depending upon the grade, the yeilds are 300-660 kg/m to the third power.
Cobalt drier: In order for the ink to dry, a cross-linkage chemical system consisting of metallic elements are used. The most popular of these oxidation catalyst elements are cobalt and manganese. Cobalt is usually extracted from cobalt ores consisting of copper or sulphide/nickel oxide mixtures and is typically considered a copper or nickel by-product. Certain parameters had to be met in this paper and further analysis of the LCA regarding cobalt extraction and refining is one of them. However, I will list the processes according to an evaluation of the 2007 Yabulu Refinery flow sheet. Cobalt Precipitation and Refining and includes: Cobalt sulfide precipitation and washing, Stage 1: Cobalt sulfide leaching and clarification, Stage 2: Zinc and iron removal by solvent extraction, Stage 3:Cobalt transfer to ammine solution by solvent extraction, Stage 4: Nickel removal by solvent extraction, Stage 5: Calcium and magnesium removal by ion exchange, Stage 6: Cobalt precipitation, Stage 7: Drying and packing, Stage 8: Zinc and iron sulfication, and finally, Cobalt product specification.
Polyethylene wax: Waxes are used in contribution of resistance of ink film properties. Polyethylene is created when ethylene is polymerize. The University of Texas conducted an overview of the Life-Cycle Assessment of the Average Gross Energy Required to Produce 1 kg of Polyethylene. The following are energy components: “electricity,” “oil fuels”, and “other.” The Total Energy in Mega Joules, regarding Fuel Productions and Delivery, Delivered Energy, and Feedstock Energy, for Electricity was 7.89 MJ, for Oil Fuels was 35.34 MJ, and for Other was 42.60 MJ. The Total energy for all Fuel Types was 85.83 MJ.
Tung oil: Tung oil comes from North America and South America shrubs called Aleurites fordii and A. montan. The seeds of these plants are roasted, then ground, and mechanically or by a solvent, their oil is extracted. Again, the process for the refining of tung oil requiring in depth analysis of a complexity of steps and generally rub proof and has the ability to dry quickly. For a basic understanding of energy implications for tung oil, I gathered data from the Environmental Assessment of Tung Cultivation Through LIfe Cycle Analysis from the International Journal of Engineering and Technology. A brief summary of tung oil production consists of 87.4 kWh of electric energy for composting, 3.5 L of fuel for soil, 2.4 L of fuel for transportation of seeds, 6,990 L of irrigation water, , 5.6 kg of formicide (ant control), and 0.6 L of diesel fuel for transport/storage.
Varnish-Soy bean oil from soybean farming: Data was provided by the NREL and covers operations related to soy bean agriculture, necessary raw-materials, and the production of the soybeans. Included in the production of the soybean are the fuel production on-farm, operations relating to agriculture, electrical generation off-site, and the manufacturing of fertilizer. Regarding the input of water for irrigation, the resources used 4,808 kg per FU (functional unit) and the next input, as CO2 sequestered by the soybean plants, was at 16.5 kg per FU. Run offs from soybean fields were most significantly from Total Kjeldahl Nitrogen, then the related phosphate-based fertilizer, phosphorus.
Phenolic Modified Rosin Resin: Resins are considered the binders in inks and contribute to the gloss, adhesion, hardness, and flexibility of the ink itself. Phenolic Modified Rosin resin is a synthetic resin that is generally good at combining with other resins and create a good resistance to rubbing.
Energy During Manufacture/Production:
Energy production for manufacture: Ink manufacture is done in large batches and utilizes the following steps: 1) use of a variable speed mixer, 2) use of a pump, 3) use of a filter, 4) distribution, 5) Z-blade mixer use, 6) de-aeration, 7) containment, 8) 3-roll mill use, and 9) the beadmill. According to the Harvard LCA case study, this process utilizes the majoirty of embodied energy in the following: Electricity Generation (28.5%) and the TOR (Tall oil rosin) Manufacture (41.8%). The production of the soy beans and the extraction of soy bean oil, and information pertaining to them were provided by the National renewable Energy Laboratory and the U.S. Department of Energy. Fuel consumption and emissions pertain to the electricity generation off-site. The growth of the soybeans neutralized any offsets of CO2 and in comparison, the printing system itself was the biggest generator of CO2. The highest energy process consisted of TOR (Tall Oil Rosin) Manufacture at 37.81% followed by Electricity generation at 25.75%, Pulpwood Production: 23.86%, Printing: 9.53%, Carbon Black Manufacture: 1.72%, Soybean Agriculture: 0.53%, Ink Production: 0.34%, PE Production: 0.16%, Crude Oil extraction: 0.11%, PMRR Manufacture: 0.04%, Flax Seed Processing: 0.04%, Formaldehyde Production: 0.03%, and Tung Nut Milling: 0.01%. At previously stated, electricity Generation and TOR Manufacture are the leading causation agents of the most embodied energy.
Energy During Distribution:
The information regarding the transport of the inks was rather sparse and complex at that. I decided to keep the distribution based on overseas whole sale manufacture.The whole sale manufacture of inks from overseas usually means a transportation method via container ship. The energy used during this distribution method is interpreted via the fuel consumption. At 24 knots per day, the typical fuel consumption of a container ship is 225 tons of bunker fuel. This depends upon the speed and size of the ship.
The process to disassemble and recycle soy based inks consists of a process called de-inking, followed by pulping the paper in order to recycle it, and then recycling it. To de-ink the paper, the paper must be washed and put through a process involving flotation. As the paper is washed, and a foaming agent along with air is added. The paper essentially becomes fibrous, and the ink gets carried away (floated away) by the foam/bubbles that are created. This process does not remove 100% of the ink from the paper and during the separation process, this depends on the selectivity. As listed by the Clear Water Group, the ability to remove the additives in the ink from paper can be disrupted by a variety of factors, including: changes in temperature or pH, electrolyte concentration, electro-kinetic relationships, mechanical forces, and surfactant, biocide, and chemical types. In comparison to petroleum-based inks, soy based inks are easier to remove during de-inking. Using soy based inks results in there being less damage to the fiber of the paper as well as leaving the paper much brighter when the paper is de-inked and recycled.
Misconceptions about Soy-Based Inks:
A few misconceptions about soy-based inks are that soy inks are 100% soy, it is better for the environment, makes paper recycling easier, and does not emit any volatile organic compounds (VOCs). Regarding the inks being 100% soy: there are other ingredients such as resin, pigment, wax, and a variety of additives that soy ink is composed of. While it it true that ingredients in the soy inks come from renewable resources, many other components do not. The promotion of soy inks seems based upon the idea that soy and vegetable oils could be used instead of petroleum based inks for printing. In reality, petroleum is used in the soy based inks as well. Gary Jones, Vice President of the Printing Industries of America stated that to use the American Soy Associations Soy Seal Logo, “it only needs to contain the specified amount of soy oil derivatives. No other specifications regarding the other components of the ink are identified.” The soy ink could contain as little as 6% soy oil to be considered a soy ink and to have the logo Soy Seal. Additionally, it seems that the need to decrease VOCs and petroleum use in the ate 1990s and early 2000s, might have spurred the development and growth of the soy ink industry. There may have also been political and economical advantages to using soy; According to the Bureau of Engraving and Printing patent report on the Soybean oil-based intaglio ink and method for making same, the U.S. House of Representative Committee on Appropriations “requested promoting American agricultural products and reducing dependency on petroleum through the use of soybean oil-based inks in the production of U.S. securities at the Bureau of Engraving and Printing.” This report also stated that soybean oil is one of the largest agricultural crop by-products in the United States, that the U.S. is the largest producer of soybeans in the world, and is a huge exporter of soybeans to other countries. While soy-based inks serve to relieve a variety of negative environmental impacts, they do not completely solve the problems associated with the systems of producing the inks themselves. These systems are very complex and perhaps it would be an entirely new approach to printing and inks in which negative impacts of raw materials and our natural environment would cease to exist.