This letter provides information concerning Flint Group’s dedication toward providing the Printing Industry with inks that reduce the environmental impact. It also serves as an educational reference to assist with Printers that receive requests from their customers. The information below focuses on Heatset printing inks, but there is also information available on Sheetfed and Coldset inks.

Flint Group has a proud history of being an environmentally responsible organization throughout our global manufacturing sites and with the products we supply. The Agri- Web™ logo was designed and trademarked years ago to help our customers demonstrate their support of the same goals.

An understanding of the materials that make up a Heatset ink and their effect on print performance and/or print quality is necessary before any substantive discussion on the use of the terms 'environmentally friendly', or 'renewable resources', can take place.

Heatset Ink Ingredients

The constituents of a Heatset ink can be broken into the following categories:

1. Colorant
2. Vehicle
3. Additives

The colorants used in four color process printing are primarily Copper Phthalocyanine Blue, Lithol Rubine, Diarylide Yellow and Carbon Black. The three non-black colorants are all organic pigments and are produced by reacting organic chemicals derived from either crude oil or natural gas. The carbon used for the black ink is made by burning oil and natural gas in an oxygen deficient atmosphere.

The Heatset vehicle, used to transport and fix the pigment to the paper, is made up of hard resin, hydrocarbon resin, vegetable oil alkyd and middle distillate. The mixture of resins, alkyd and distillate is heated and stirred until the resin melts into solution. After cooling, the resulting vehicle (or varnish) is either mixed with the pigment and passed through grinding equipment or used in a pigment "flushing" process that produces a concentrated colorant base for use in ink manufacture.

The hard resins are produced from tall oil rosin or gum rosin. Tall oil rosin is a byproduct of the paper making industry. Gum rosin is harvested from live trees. The major additives used in Heatset ink are waxes. These are used to promote rub resistance and slip during printed product finishing and binding.

Heatset Ink Drying Mechanism

A Heatset ink film dries by removing the middle distillate. This is most commonly performed by subjecting the ink film to high velocity hot air. The heated air removes the middle distillate causing the viscosity of the ink film to rise sharply to a point where it acts as a solid. Only volatile ingredients in the ink can be removed and these are primarily distillates of varying boiling range. Any non-volatile liquid ingredients, such as vegetable oils, remain in the ink film and decrease the film’s hardness. Too much of these oils can result in an inability to dry the ink film adequately, no matter how much heat or air velocity is applied.

Vegetable Oils

Heatset inks have always contained some vegetable oil. The vegetable oil is used to produce alkyds that are used in the pigment grinding process due to their excellent wetting properties. The most common vegetable oil used in Heatset inks up until the 1990’s was linseed oil.

During the 1990's, the American Soybean Association (ASA) promoted their soybean oil product for use in all types of oil-based inks. As lobbyists for soy bean growers, their objective was to find ways to increase the demand for all types of soy products. The ASA initially set a limit of twenty percent soybean oil to be used in Heatset inks to obtain their Soy Seal denoting compliance to this level. However, it was obvious to anyone working in the ink industry that this level was far too high and that the inks would remain "wet" because the soybean oil is non-volatile. The ASA eventually decided to survey the major ink manufacturers in the United States regarding the level of soybean oil that technical personnel felt was practical. After collating the results, the ASA decided that a minimum of seven percent of soybean oil in any given Heatset ink would be necessary for this ink to display the Soy Seal. Incorporating soy oils into printing inks was deemed such a success that the National Soy Ink Information Center has been discontinued.

The logo below is still used today to identify inks that contain the qualifying percentages of soy oil:

Today, Heatset inks usually contain a mixture of vegetable oils to obtain the beneficial properties of each of these oils.

Renewable Resources

The most common renewable resources used in Heatset inks are soybean oil, linseed oil, castor oil, tall oil rosin and gum rosin.

The amount of renewable resources that can be incorporated into a Heatset ink formula is limited by the hardness of ink film required to travel through the steps necessary to complete the print job without marking or smearing the printed piece. The amount of ink absorption into the paper can also affect the drying of the ink. Generally, the more the ink is absorbed into the paper, the greater the percentage of vegetable oil that can be used in the ink formula.

The ink series manufactured by Flint Group for typical types of ink contain the following percentages of renewable resources:

ARROWEB HEATSET INK

Breakdown by Weight Percentage

The amount of soybean oil in the ink formula can be increased to achieve the required seven percent minimum that the American Soybean Association needs for the inks to carry the Soy Seal but this will normally be at the expense of other renewable resources in the ink. Replacing the components above with soy oils would have the same net effect on the total renewable content but may inhibit the performance characteristics of the inks for our customers and yours.

Conclusion

Heatset inks have always contained renewable resources but the amount that can be incorporated into the ink formula is dependant on many variables found in the printing process. These variables include paper type, finishing equipment, the end use of the printed piece, ink strength and the number of ink sets that a printer is willing to inventory.

Due to the drying mechanism used in Heatset printing and the fact that inks have to be oil based to interact appropriately with the fountain solution, the use of petroleum based products as a major ingredient in the formulation of inks is necessary at this time for Heatset printing. However, we have several active projects to decrease our dependency on petroleum based products and will continue to find new and innovative ways to incorporate renewable or recyclable materials in to our Heatset inks. Awareness by print buyers of the other renewable resources contained in the inks, the limitations to the print process, and potential manufacturing cost increases, should assist with the print buying decisions.

Flint Group Agri-Web™

To address the increasing desires of print buyers to specify printed products that are more environmentally conscious, Flint Group is providing this communication and a means to identify inks that qualify as such. The Agri-Web™ logo and its philosophy are designed to help print specifiers with the assurance that although the inks may not use the percentage of soy oil required by the Soy Association to merit use of the soy seal, they utilize a combination and level of resources that are no less renewable while ensuring optimal on-press performance.

The Flint Group Heatset inks provided, including four-color process and special colors, all qualify for Agri-Web™ labeling since they contain the previously mentioned renewable oils and rosins in much greater percentages than would be possible with soy oil alone.

Your local Flint Group representative will be happy to assist with any questions or customer inquiries requiring additional information on all printing ink types and renewable resources.