INX International, provider of inks for commercial printing, packaging, and digital printing, has put together a primer for understanding the environmental effects of printing inks; from ink's carbon footprint and recycling to the recycling of printed corrugated. Yesterday, in Part One of this three part series, we took a look at the formulation of inks, de-inking of printed products, disposal and recycling, as well as a look at ink's carbon footprint. Today, in Part Two, we examine biodegradability and recycling issues of ink and printed products. How does ink affect the biodegradability of printed materials? While there is some evidence that vegetable oils themselves are more biodegradable than petroleum oils, no difference in biodegradability of a printed substrate would be anticipated. Biodegradability of printed matter is a function of the biodegradability of the substrate, not of the dry ink film. What happens to the printing ink during the recycling process? The de-inking plant utilizes office wastepaper and other paper waste streams as feed stock to recycle paper by removing the ink and other contaminates to produce a clean, bright, market pulp which will be sold to producers of printing and writing grades of paper. Rejects from the process collected in the de-inking process rejects collection tank are dewatered and pressed by a belt filter press in the de-inking plant. Polymer will be added to the sludge prior to the sludge press to enhance the dewatering of the sludge. Pressed sludge is collected in a bunker and loaded on a truck for landfill disposal. The press filtrate is collected and the pH is adjusted and sent to the primary clarifier for wastewater treatment. On its way, polymer is again added to aid in reducing biological oxygen demand (BOD) and total suspended solids (TSS) in the clarifier. This is also a normal practice found in most de-inking mills for effluent enhancement. What happens to the ink once it is removed from the paper? Ink and stickies (sticky materials like glue residue and adhesives), are trapped in the froth produced during the flotation de-inking process. This material is collected, and much of its water is removed and reused at the paper mill. The remaining material, which is still 30%-50% water, also contains very small fibers which have washed out of the pulp during the de-inking process. This material can be burned to make energy, composted, or land filled. It can also be used to make concrete and gravel for roads. The disposal method depends upon the material's final content. In a typical de-inking plant, every 100,000 dry pounds of recovered paper placed in the pulper will result in as much as 35,000 dry pounds. of ink, stickies and small fibers. Are different types of ink more readily removed from the printed substrates? NAPIM (National Association of Printing Ink Manufacturers) has no experimental data on the de-inkable characteristics of soya ink versus other paste inks. A review of typical formulations suggests, however, that there would be little or no difference in de-inkable properties between soya or other vegetable oil inks and petroleum based inks. Is the de-inking sludge from soya based inks less hazardous than the de-inking sludge from other types of inks? NAPIM has no experimental data on de-inking sludges. However, since the pigments in soya inks are identical to pigments used in other types of inks and since the vehicle, resins, driers and additives are either identical to, or similar to petroleum based ink, there is no reason to expect that the sludges resulting from the de-inking of soya inks would be less hazardous than other de-inking sludges. Are your inks biodegradable? INX has reviewed the ASTM test methods D 6868-03 and D 6400-04, regarding the specifications for compostable plastics. Our investigation of our product lines reveals that our products have not been tested under the criteria described in these ASTM methods, so we cannot say that we have products that meet these test method requirements. We would like to take a moment to observe that these ASTM methods appear to be written for the plastic itself, not the printed matter on the plastic. A short lab study shows that ink applied at 100% coverage over a sheet of plastic makes up 0.6% total weight per square inch on a 13 thousandths thickness styrene. In ASTM D 6400-04, Section 6.2 Disintegration During Composting, it notes that satisfactory disintegration occurs if after controlled composting, less than 10% of the original dry weight remains after sieving. With the weight of the ink making up so little of the typical total weight of a printed piece, it may not even be a consideration in the testing. We at INX are not aware of any product on the market that would have been tested under these ASTM methods regarding the specification for compostable plastics. Are your printing inks biodegradable or compostable? Biodegradability and compostability for inks and coatings are complex subjects. There is little scientifically-based lifecycle analysis research in these areas. But we have seen testing which indicates that mass of ink present on most packaging is so small that it does not interfere with substrates that do biodegrade or compost. Wal-Mart has exempted inks, coatings and adhesives from their scorecard activity at this time. Again Wal-Mart recognizes these materials make up a very small portion of the mass of the entire package. Ink will represent less than one percent of the total mass of many packages. It makes little sense to expend significant effort and resources to make changes to a material that will have a minimal overall impact on the biodegradability/compostability of the packaging. In addition, inks are the visible part of the package the consumer sees. Inks have significant impact on the final performance and esthetics of the package. The recycle content on paper can be changed and the consumer will likely no notice the change. A brand product must be very careful in making a packaging change. If a change is perceived, the consumer may wrongly believe that the product has also been changed. For all of these reasons inks may be a high risk change, and are well down the list of items that will changed based solely on sustainability. Tomorrow, in Part Three of this series we will address recyclability of corrugated.