Much is being said about "green" materials and "sustainable" development and many past SpecialChem articles and editorials discuss these concepts. There is no doubt that adhesives and sealants play a large role in our initiatives to protect the environment and resources for future generations. Adhesive development today encompasses ecological issues, such as recycling and recovery, renewable materials, and even common-sense design strategies such as minimizing product size and weight. They are changing the way products are being designed, produced, and discarded.
However, sometimes adhesive and sealant manufacturers do not see opportunities for sustainability in their own backyard. I believe that this is especially the case with regard to the packaging of adhesives and sealants for sale and distribution. Adhesives suppliers and developers are eager to sell "green" products to the eagerly awaiting packaging industry, but they do not look at packaging developments that may be of benefit to them in their own processes. This editorial takes a quick look at two of these developments.
Six rules of thumb (Table 1) may help the packaging designer better focus on environmental improvements either as a brainstorming activity or to guide the product development process. These six rules have emerged out of the original three R's of reduce, reuse, recycle which have long been associated with the environment. They have been the basis for innovative packaging products for the adhesive or sealant supplier.
Rethink the product and the functions
Reduce the energy consumption and resource consumption along the entire life cycle
Replace hazardous substances with more environmentally sound alternatives
Use those materials which can be reused or recycled
Design in such a way that the product or parts of it can be reused
Design a product that is easy to repair and service through the value chain
1: Six Rules of Thumb for the Sustainable Packaging Designer
One unique concept has been developed to package hot melt adhesives that saves material (both the packaging and the contents), provides improved quality and customer satisfaction, and reduces costs. This is a continuous "sausage" packaging process that co-extrudes a hollow sleeve of thermoplastic around one to two pound sections of hot melt adhesive as it comes off the mixing extruder (Figure 1). The thermoplastic shrinks onto the hot melt when cooled and provides not only a durable packaging but one that prevents blocking of hot melt sections. Some types of the co-extruded packaging (e.g., wax coating or EVA) may be compatible with the adhesive so that the "sausages" can be dropped into the melt tank without removing the packaging skin.
Figure 1: Coextrusion of wax coating onto hot melt product for shipping and storage (US Patent 5,669,207).
The sausage packaging concept has been extended to sealants as well. Sealants or adhesives can be encased in thin, tough, aluminum foil instead of the more well recognized plastic or coated cardboard caulking cartridge. The sealant or adhesive can then be dispensed manually or pneumatically with versatile applicator guns which can accommodate various size sausages. The advantages of this concept are:
Very low packaging cost compared to standard cartridges
Very little left over waste material
The minimal amount of aluminum foil is recyclable.
The package is an integral part of the product used by the customer, and environmental benefit or evils can come from both the package and its contents. The two examples illustrated above show how the adhesive or sealant supplier can provide innovative and environmentally sound packaging.