For years, the industry has promoted water-based adhesive (acrylic, urethane, etc.) alternatives to solvent-based adhesives as the answer to environmental concerns related to volatile organic components (VOCs). Now the realization that “it’s the percent solids stupid” is taking hold.
Although the adhesives and sealants industry is not as far along the sustainability learning curve when comparing it to the packaging industry as a whole, it is clearly aware of the need to consider and implement sustainability solutions. An example of this renewed awareness is the first industry-sponsored ASC Sustainability Conference.
The Adhesive & Sealant Council (ASC) held its annual conference late last year, where it was a good chance to check the pulse of the state of bioplastics in this industry.
The largest segment for adhesive usage by volume is packaging and that segment is even larger when packaging tapes and labels incorporating pressure-sensitive adhesives (PSA) are added. The adhesive industry usually reports tapes and labels as a separate end-use segment.
An oft- heard phrase is “adhesives are the last thing considered when designing a package and are used in such small per-package quantities that they are often ignored.” This position is changing. The new awareness is being driven by the same drivers that affect packaging overall. They include Wal-Mart and other retailers subscribing to a sustainability agenda, brand owners demanding their value chain partners supply them with sustainable raw material offerings and the consumer demanding less packaging materials being used, more and clearer options regarding end-of-life alternatives, pricing parity and products that are safe.
Discussions and presentations at the ASC Conference focused on addressing some of these issues:
• New focus on recycle contamination: Wal-Mart and adhesive companies are supporting the Association of Postconsumer Plastic Recyclers protocol for evaluating labels and adhesives used on polyethylene terephthalate (PET) packages and their compatibility with PET recycling. This protocol encourages the design of packaging for greater recyclability and improves the quality of post-consumer PET entering the recycle system.
Although not discussed at the conference, adhesive-based recycle contamination is a broader problem than just PET packages. It is present in the recycle of PET bottles, high-density polyethylene (HDPE) bottles, multilayer film laminations, coextruded tie layers and laminating adhesives and paper products (corrugated) with the ever-present adhesive-caused “stickies.”
• Renewable hot-melt adhesives: DaniMer Scientific, took the opportunity at the Conference to provide detail on their biomass-sourced, renewable hot-melt adhesive (RHMA). Four to five bioplastic grades will be offered for such end-use applications, like a hot melt PSA for labels. The specific technology was still not totally revealed; however, ample pilot plant quantities exist for development.
• Absence of bio-based renewable polymer chemistries: As a presenter, I discussed the multitude of new bio-based renewable polymer chemistries that are being introduced as replacement technologies for petroleum-based materials in other end-use plastic markets like film packaging applications, automotive, consumer and durable products. The staggering flurry of global renewable activity present in the olefin, nylon, polyurethane, acrylic and styrenic products, all bases for compounded adhesive technologies, has not seemed to have entered adhesive markets as yet.
A Need for Proactive VendorsPart of the reason for this is the relatively small polymer volumes most adhesive applications provide as opportunity for adhesive raw material suppliers. When polymer companies look at their opportunity hierarchy, adhesives often do not make the “new product development” cut. Adhesive companies will have to be more aggressive with their suppliers by demanding development opportunities so they can cash in on sustainability solutions that renewable bio-based plastics can provide.
Adhesive & Sealant Council
Association of Postconsumer Plastic Recyclers