Go Green by Reducing VOC
Initiatives for reducing environmental impact have been in place for several years with converters asking, “How can I be Greener”? “What can I do to reduce my Carbon Footprint”? Initially, options were very limited in the adhesives and coatings space and those that did exist had limited performance. But in recent years many suppliers have invested a great deal of development time in this space and a variety of options now exist. The three options we will highlight in this article are high solids solvent based adhesives, high performance water-based adhesives, and new solventless adhesives. When evaluating new adhesives and coatings several factors must be weighed including converting equipment and end use of the laminate.
The first option for discussion is high running solids solvent based adhesives. Historically solvent based adhesives were applied at 25-30% solids. Often in an aromatic, ketone, or ester type solvent as the carrier. These products typically had very good performance characteristics. In the last few years adhesive suppliers have been able to push the applied solids to 50-55% allowing a reduction in solvent emissions of nearly 50%. This has been done without sacrificing performance. In some cases, these products are also available in a solvent system that is HAPS (Hazardous Air Pollutant) free and VOC (Volatile Organic Compound) free. This option allows a converter to use their same coater/laminator as well as thermal oxidizer or solvent capture system. Applied costs are very often reduced with the benefit of reduced emissions.
The option is running a waterborne adhesive or coating. In this instance the solvent carrier has been replaced by water. These systems can be run on existing equipment at relatively high solids of 45-55%. Often just minor tweaks to the existing dryer settings are necessary to facilitate thorough drying of the adhesive or coating. Chemistry advancements on these systems has pushed their performance well into the medium to medium high category. These products can be used in anything from a confectionery bag up to a hot fill or boil in bag package.
The final option is switching to a solventless adhesives. These types of products are 100% active with no volatile solvent or water as carrier. Great advancements have been made in this area in recent years to boost performance. Performance now spans general performance applications up to and including retort packaging. Unlike the first two options however these products will not apply on existing equipment typically used to run solvent based or water-based adhesives and coatings. Special lamination and mix meter equipment are used for these products. This equipment will not run the other types of products (except in cases of Duo or Combi equipment) so an informed decision must be made to move and stay in this direction.
As is evident from above there have been several advancements in recent years by adhesives and coatings suppliers to make their products “Greener”. Each option has its pros and cons. A converter should work closely with their supplier to match the option that best fits with their existing or planned manufacturing operation. This includes the type of existing equipment they have or intend to purchase and the end use of the packages they intend to produce. In general, any one of the three above mentioned options could be a viable alternative to pursue. Dow have all three options available and have firsthand knowledge of comparing each side by side.