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Printech, July, 2000
Soy Ink Information


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From:GaryJGATF(gjonesprinting@aol.com)
Date:Mon, 24 Jul 2000 14:25:26 EDT


Lynsey: 1. First and foremost, the definition of a soy-based ink needs to be clarified. There is no universal definition and a "soy-based" ink could have as little as one drop of soy oil in it and as much as 100% of the oil content being soy oil. There is a set of informal standards established by the American Soybean Association addressing the minimum level of soybean oil content that allows for the use of the SoySeal logo. These are the recommended percentages: · Black News Ink 40 percent of total formula weight · Color News Ink 30 percent of total formula weight · Sheet-fed Ink 20 percent of total formula weight · Heat-set Ink 7 percent of total formula weight · Cold-set Ink 30 percent of total formula weight · Business Forms Ink 20 percent of total formula weight Soy ink may contain other vegetable oils--classified as drying oils--but soybean oil must be the predominant oil. Vegetable drying oils may be added as needed, but they must not exceed the level of soybean oil set forth in the respective formulation. Contacting Jo Patterson at soyink@soyink.com, 800/747-4275, or at their web page www.soyink.com can obtain more information about the SoySeal logo. 2. There are several studies on soy-based inks that may be of interest to you. Two of them focused on the recyclability of paper printed with soy-based inks. Another study was the first in a series dedicated to the life cycle analysis of soy-based inks. Study Summaries A study conducted by Bruno Carré et. al., entitled "Deinking difficulties related to ink formulation, printing process, and type of paper" examined the deinkability of some different ink formulations, printing processes, and paper types. The paper appeared in the June 2000 issue of the TAPPI Journal and can be obtained on-line at www.tappi.org/public/tappi_journal.asp. Specifically, the paper focused on deinking problems caused by vegetable-oil-based newsprint offset inks, offset heat-set inks, and red rotogravure inks. It concluded that conventional alkaline deinking can produce good results, but the wide variety of paper types, ink types, and printing techniques often leads to poor deinkability, producing pulps with low brightness, high speck contamination, or residual color. With respect to deinkability of reformulated vegetable ink, it concluded that vegetable-based inks are attractive because they use a renewable resource while reducing emissions of volatile organic compounds. The downside is that deinking performance has been less than satisfactory. However, the deinkability of vegetable inks can be greatly improved by changing the resin in the formulation. Results show that the improved vegetable ink and standard mineral inks provide equally good deinkability. Indeed, the improved vegetable ink provides higher brightness along each step of a flotation deinking process. The second study on the deinkability of soy-based ink printed products appeared in the May 1999 issue of Progress in Paper Recycling. It was conducted by Jan Pekarovic and was entitled "Deinking of Aged Soy Ink Printed Offset-Environmental and Technological Aspects". The research examined the influence of aging on the deinkability of soy and petroleum based inks used in offset printing. The environmental impact of deinkability as measured by chemical oxygen demand (COD) and biological oxygen demand (BOD5) and some pulp quality parameters as measured by brightness, ash content, and fiber loss. It concluded that the characteristics in the paper such as concentration of fillers, had the most noticeable affect. There was no significant difference between petroleum and soy-based inks in deinking ability and COD and BOD values in wastewater generated from the deinking process. The contact information for Progress in Paper Recycling is at 920-832-9101 or http://www.recycle.net/pub/ppr_wi.html. The first study pertaining to life-cycle assessment of soy inks was conducted by Battelle, Columbus for the Iowa Soybean Association and was entitled "Benchmark Life-Cycle Inventory and Impact Assessment of Sheetfed Printing System Using Soy-Based Ink". The purpose of this study was to document the life-cycle environmental impact characteristics associated with the use of soy-based inks by evaluating a typical ("generic") soy-based ink currently used in significant quantities for sheetfed offset lithographic printing. This typical soy-based ink printing system will serve as a benchmark for future comparison with alternative ink formulations and other combinations of printing system materials. The scope of the study included a streamlined life-cycle inventory (LCI) and impact assessment (LCIA). Since the LCI was streamlined, materials, processes, and even life-cycle stages that are the same between different printing inks, or were less than one percent by mass of the printing system inputs, were excluded from the analysis. Data on emissions and resource use collected for the LCI included site-specific primary data from GATF-member sheetfed print shops (printing exclusively with soy-based ink), site-specific secondary data (carbon black and Kraft pulp manufacture), and generic secondary data (all other modules). The LCIA included identification of specific processes in the streamlined life-cycle of soy-based ink for sheetfed printing that make the greatest contribution to the overall environmental profile for the baseline printing system selected. The LCIA methodology adhered to applicable international standards and guidelines. The LCIA approach included both regional scaling for areas that differ in sensitivity to certain impact indicators and normalization against a reference value. It is important to note that the equivalency models used are assessments of potential hazard and not a representation of actual impacts. The final report was reviewed and approved by an external review team for compliance with the developing guidelines in ISO 14042. Although this benchmark LCI and LCIA was designed for future comparison with similar studies of other ink formulations and printing materials, the following are five key observations: · Soybean agriculture uses only 0.5 percent of the total energy used in the soy ink life cycle. · Soybeans temporarily remove damaging carbon dioxide, a greenhouse gas, from the atmosphere. The current shift toward minimum- or no-till farming methods should be expanded, since low till reduces water runoff and slows the release of carbon dioxide back into the air when the soybean plant decays. · Tall oil rosins - used to manufacture many types of ink - are the primary contributors to soy ink's ozone depletion potential. Two options for reducing the ozone depletion potential from use of TOR are: (1) reducing the quantity of TOR used in the formula by replacing it with soy oil and (2) make ink with TOR supplied by manufacturing facilities with reduced emissions of ozone depleting chemicals. · The majority of air emissions released during soy ink's life cycle result from fossil fuel combustion. Extraction and processing of raw materials for other printing ink ingredients share the burden for release of these emissions. · Five of the 14 major soybean-growing states, representing 41.2 percent of production, use a sustainable resource - rainfall - for soybean farming. The nine remaining states use irrigation for soybean farming, but only two of the nine have such a limited supply of surface water and groundwater that irrigation use is a concern. Contacting Jo Patterson at soyink@soyink.com, 800/747-4275, or at their web page www.soyink.com can obtain more information about this study. 3. Regarding research ideas, it would be great if someone could conduct a control ink mileage study comparing the amount of printed matter that can be printed using conventional petroleum ink as compared to the exact same ink formulated with soy oil. The same paper and coverage level would have to be used. 4. Samples of soy ink can be obtained from Jo Patterson at soyink@soyink.com, 800/747-4275, or at their web page www.soyink.com. 5. Another benefit associated with soy inks is the potential reduction in the release of volatile organic compounds (VOCs), which contribute to the formation of ozone in the lower atmosphere, from printing inks. The issue of VOCs from a regulatory perspective involves two components, VOC content and VOC release. EPA requires that the VOC content of lithographic ink be measured with a specific test method called Method 24. A 0.3-0.5 gram sample of ink is heated to 110oC for one hour and the weight loss, corrected for water content and exempt compounds is used to determine VOC content. The definition of a VOC is not necessarily clear as EPA is in the process of reexamining its approach for "photochemical reactivity" measurement, but EPA does have a list of exempt VOCs. A good rule of thumb is that if the chemical, especially organic based ones, is not on the list of exempt compounds and it evaporates at ambient or elevated temperatures, then it is a VOC. A very common misconception made about offset lithographic printing inks is that VOC content somehow equates into VOC emissions. This is not true because the ink oils or "solvents" used in lithographic inks are high boiling, low vapor pressure hydrocarbons. Ink oil is composed principally of normal paraffins and naphthenic fractions of a petroleum distillate. These oils possess a vapor pressure of less than 0.1 mm Hg at 70oF. Sheetfed ink oils usually have initial boiling points greater than 500oF and boiling ranges extending up to 800oF. Nonheatset web offset ink oils have initial boiling points greater than 500oF and boiling ranges extending up to 1000oF. Newsprint ink oils have boiling ranges extending up to 1000oF. EPA recognized the lack of significant emissions from sheetfed and nonheatset web offset inks in the November 1993 draft of the Control Techniques Guideline for Offset Lithography (page 2-7 and 2-8). According to the document, EPA is not going to require the reformulation of nonheatset web and sheetfed inks because of the extremely low VOC emissions associated with them. Only 5% of the VOC content of these inks is actually emitted into the atmosphere. A study conducted by Battelle Memorial Institute, Columbus, showed that 93 +/- 4 percent of the ink oil was retained in sheetfed printed substrates. The remainder of the VOC is retained by the substrate throughout its distribution and disposal as confirmed by a memo to the CTG file. In examining the VOC content associated with soy inks, it can be seen that the VOC content is typically less than its petroleum oil-based counterpart. For example, a soy-based sheetfed offset lithographic will contain about 3-5% VOC content, while the same petroleum-based ink will have a VOC content of about 15-20%. In considering emissions, one pound of sheetfed ink will emit 0.0025 pounds of VOC (1 X 0.05 x 0.05), while one pound of petroleum sheetfed ink will emit 0.01 pounds of VOC (1 x 0.20 x 0.05). Based on the VOC content times the release factor, it would appear that the soy ink does release less VOC and has a distinct advantage in this area. However, this does not present an accurate representation of VOC emissions. Vegetable oils will auto-oxidize and form bonds across points of unsaturation in the molecule. This bond formation is called polymerization and this is how these oils dry and form a film. In fact, sheetfed inks take advantage of this property as they use drying oils as part of the formulation to help form a film to protect the pigment from being removed from the surface of the substrate. Catalysts are actually added to sheetfed inks to increase the oxidative polymerization of the film formers. In the process of oxidative polymerization, the vegetable oils release VOCs in the form of aldehydes, ketones and alcohols. It is for this reason why EPA would not exempt vegetable oils as VOCs. EPA's position is that while it appears that the vegetable oils themselves are not VOCs, due to their low volatility, they are precursors to precursors of ozone and as such could not be considered exempt as VOCs. EPA drew its conclusions based on a series of evaluations with the results contained in a document entitled "The impact of Declaring Soybean Oil Exempt from VOC Regulations on the Coating Program" (EPA-450/3-91-011), April 1991. Applying the results of vegetable oil oxidation means that as the vegetable oil content in a lithographic ink increases, its VOC emissions will also increase. This phenomenon quickly eliminates the advantage in reduced VOC emissions that soy-based inks seem to enjoy based on just VOC content comparison. If you need more information, let me know. Gary Jones Graphic Arts Technical Foundation 200 Deer Run Road Sewickley, PA 15143 412/741-6860 x608 - Phone 412/741-2311 - Fax MARK YOUR CALENDAR! March 25-27, 2001 National Environmental, Health and Safety Conference for the Graphic Communications Industries, Adam's Mark Hotel, St. Louis, MO



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