"Green gluing" or "sustainable bonding" are current buzzwords in the packaging industry. But what does sustainability mean? Within the UN sustainability criteria and the Product Environmental Footprint criteria (PEF), not all goals are equally achievable. The best possible compromise must be found. In the public discussion, however, individual criteria are emphasised and weighted differently depending on the interests at stake. This leads to uncertainties and sometimes contradictory statements. Baumer hhs Managing Director Percy Dengler and Thomas Walther, Head of Business Development at the company, take a critical look at the issue.
How does Baumer hhs approach the topic of sustainability?
Percy Dengler: As a partner to the packaging industry for industrial adhesive application, Baumer hhs faces these questions, among others: How do we, our customers and our industry partners define the term sustainability? What influence does adhesive application have on the sustainability of packaging? Adhesive bonding is a core process in packaging production. But adhesive application is only one link in the value chain. From our point of view, the UN sustainability goal of partnership is one of the most important. Because only implementation in partnership creates the conditions for true sustainability. This also applies unreservedly to packaging production. That is why we cooperate closely in research with industry partners and customers to jointly work out the potential for improved sustainability in packaging production. There is no question: the future belongs to sustainable bonding.
Who are your cooperation partners?
Thomas Walther: For example, the Europe-wide initiative 4evergreen has set itself the goal of increasing the contribution of fibre-based packaging to a sustainable circular economy in order to minimise the impact of packaging on the climate and the environment. As a founding member, we are actively involved in this initiative. Other 4evergreen members include Nestlé, Danone, Procter & Gamble, Westrock, AR Packaging, many cardboard and paper manufacturers and recyclers. This alliance thus brings together the entire value chain. In addition, Baumer hhs is involved in bilateral cooperations with adhesive manufacturers and customers worldwide. Our company is open to any partner who wants to advance the topic of sustainability.
Percy Dengler: Our approach is "Rethink", i.e. to think about the right things first before doing those things right. We want to rethink adhesive application. We approach the subject holistically and are in intensive discussions with customers, industry partners and research institutes at various levels. So we are not "green washing".
What are the most important aspects in your holistic approach?
Percy Dengler: The answer to the question of how industrial adhesive application can support the packaging industry's efforts towards more sustainability is extremely complex. Many things that appear sustainable at first glance turn out to be critical in the overall balance. The sustainability of packaging can only be assessed if its entire life cycle is considered. Unfortunately, the public discussion is dominated by individual aspects that merely pick out single sustainability criteria that are favourable to individual suppliers.
The reorientation of industrial adhesive application begins with the development of bio-based, sustainable adhesives through the establishment of a functioning circular economy to the further optimisation or minimisation of adhesive consumption. In addition, we will provide even more targeted support to our customers to achieve maximum energy efficiency in their bonding processes and to avoid waste. We have always focused our technology and solutions on optimised adhesive consumption, maximum energy efficiency and waste avoidance, but we still see potential for further improvements here. Bio-based adhesives and the development of a functioning circular economy, on the other hand, are comparatively new topics for us. We always want to keep an eye on the entire value chain and critically question ourselves again and again.
What exactly are bio-based adhesives?
Thomas Walther: In today's adhesives, additives from fossil, non-renewable raw materials are generally used. One example are polymers that are produced on the basis of petroleum. In view of the growth of the world's population and the globally increasing demand for packaging, the packaging industry is challenged to resolve the tension between growth and resource scarcity and to significantly improve the life cycle assessments of its products and processes. Bio-based adhesives made from renewable raw materials can make a contribution to this.
Which renewable raw materials are we talking about?
Thomas Walther: We are talking about starch-based raw materials, natural resins, natural rubber or natural latex, for example. From the point of view of Baumer hhs, however, it would be better to rely at least in part on biomasses that are waste products from other processes or agriculture.
For example?
Thomas Walther: Among other things, we see interesting potential in harvest residues from grain production and other areas of agriculture, as well as in lignin, which is produced in large quantities in the paper and wood industry. Here, this substance is ultimately a waste product. Lignin is a carbon compound that, with its specific properties, has the potential to replace synthetic additives in the production of adhesives.
What criteria generally determine whether biomasses are suitable for industrial adhesives?
Thomas Walther: There are a number of factors. For example, adhesives made from biomasses must offer the same application properties as conventional adhesives, so that there is no reduced output or higher error rates and thus more waste in packaging production. Otherwise, sustainability is only on paper. The task of research is therefore, among other things, to investigate the application properties of bio-based adhesives from the outset. Baumer hhs, for example, successfully applies starch-based adhesives in selected industrial segments. However, these adhesives are not yet suitable for the high-speed machines used in packaging production. In many cases, certain properties such as their application quality, their long setting times and their low gap bridging are not sufficient for this. We are researching the application and bonding properties of bio-based adhesives ourselves, but we are also active partners in research networks.
Doesn't starch belong in the food sector?
Thomas Walther: Yes, of course. Even with sustainable raw materials, it is important to weigh up conflicting goals. Increasing demand for starch could drive up the prices of certain foodstuffs. An increasing demand for natural rubber could lead to the clearing of rainforests in order to plant rubber plantations. Furthermore, in the case of adhesives made from natural rubber, the costs of extraction and their transport, including the CO2 emissions caused in the process, would also have to be considered. At the same time, social issues need to be analysed. Does the plantation economy possibly endanger the supply of agricultural products to the local population? Does the plantation economy benefit the population or does only a few large landowners profit from it?
Percy Dengler: The framework conditions for the production of biomasses are one of the factors that determine their sustainability. Together with our industry partners, we base our assessment of these raw materials on the criteria of the UN's 2030 Agenda for Sustainable Development at the economic, social and ecological levels. Within the framework of a life cycle assessment (LCA), we consider their entire life phase, including any conflicts of objectives with other areas. This means that we deal with these complex issues in depth in order to achieve true sustainability in mechanical adhesive application.
Why is Baumer hhs, as a manufacturer of solutions for industrial adhesive application, so intensively involved with sustainable adhesives?
Percy Dengler: Intensive know-how transfer between Baumer hhs and its industrial and research partners is a basic prerequisite for the development of suitable solutions for industrial adhesive application with bio-based adhesives. Sustainability must go hand in hand with the packaging industry's high demands on productivity, quality, reliability, flexibility and cost-effectiveness, among other things. To ensure this, Baumer hhs, the adhesive manufacturers and the research partners work closely together in adhesive development. Our comprehensive practical knowledge around industrial adhesive application flows into the development of sustainable adhesives just as the expertise of the adhesive manufacturers flows into the development of our adhesive application solutions. Where necessary, we adapt these to provide the required productivity, quality, reliability, flexibility and cost-effectiveness in our customers' processes. The entire process must be coordinated with each other. Only then does it deserve the label "Green Gluing".
In the case of food packaging, there is another important aspect: bio-based adhesives are provided with additives, as the case may be. Here, it must be ruled out that harmful components can migrate into food.
How do you see the regulatory measures such as, among others, the EU plastics strategy and the strengthening of the polluter-pays principle through the introduction of extended producer responsibility with regard to the environmental impact of packaging?
Percy Dengler: From the point of view of Baumer hhs, these measures are to be welcomed, as they initiate a necessary development. The market demands that the packaging industry improve the reputation of its products. It must produce them as environmentally friendly as possible. And the packaging itself must be as environmentally friendly as possible. With our sustainability strategy, we want to support our customers in the production of environmentally friendly packaging as effectively as possible. Environmentally friendly packaging secures jobs in the packaging industry and in its supplier companies.
In addition, regulatory measures are driving new developments. For example, in a short period of time we have received an astonishing number of requests for machines to apply adhesives in the production of paper-based straws and cups. These paper-based straws and cups are increasingly replacing disposable plastic products.
What about the issue of economic efficiency with biomasses?
Percy Dengler: Adhesives made from biomasses must have a comparable price-performance ratio to conventional adhesives. This means that adhesive production needs biomasses that are available or can be produced in sufficient quantities. Petroleum-based raw materials used in the production of conventional adhesives are subject to price fluctuations. These should be excluded as far as possible in the case of sustainable adhesives. This would be another advantage of bio-based adhesives.
Do adhesives made from biomass offer advantages in recycling?
Thomas Walther: Some manufacturers even advertise their bioadhesives as compostable. From the point of view of Baumer hhs, however, the goal cannot be to compost paper-based packaging or to add it to the landscape. Our goal is recycling - in other words, a functioning circular economy that ensures the recycling of packaging materials and thus minimises the environmental impact of packaging. Conventional adhesives can negatively affect the recycling process of paper-based packaging. This is especially true for hot glues. That is why end-packers, for example, are trying to replace them with more easily recyclable cold glues.
In the meantime, more and more hot melt adhesives based on biomasses are coming onto the market. With regard to the issue of sustainable bonding, this is basically to be welcomed. But here, too, the effects on the recycling process must be analysed. Regardless of the basis on which they are formulated, hotmelt adhesives have one thing in common: in the preparation of recovered paper and in the production of recycled paper, they tend to form sticky impurities. These can impair the quality of recycled papers and cause costly malfunctions in the paper machines. Baumer hhs already has some positive experience with hotmelt adhesives that are at least partly based on biomasses. But here, too, there are still open questions.
The easier packaging is to recycle, the less it costs to recycle. So ease of recyclability also benefits the economic viability of packaging. In addition, easier recyclability promotes the level of recovery of valuable fibres and supports the achievement of the recovery targets of the EU Circular Plan.
Some time ago, you launched GlueCalc, an intelligent app for smartphones that packaging manufacturers can use to minimise or optimise their adhesive consumption. Shouldn't we generally strive to minimise the use of resources in packaging production?
Percy Dengler: Yes, of course, and the industry is working on this across the board. With GlueCalc, packaging manufacturers and end-of-line packagers can quickly and easily calculate, on a job-by-job basis, the extent to which they can reduce their adhesive consumption and CO2 emissions by switching their adhesive application from beads to dots. In this way, many of our customers have reduced their adhesive consumption and CO2 emissions by 50% or more. At the same time, this means that the packaging they produce contributes less adhesive to the recycling process.
Our electromagnetic adhesive application valves offer the precision required for applying small dots of adhesive. In addition, they are characterised by a particularly long service life compared to electropneumatic valves. This is also an important point: with these valves, it is impossible for higher wear to cancel out the ecological and economic advantages of the savings in adhesive consumption.
At the same time, the reliability of the technology minimises waste in packaging production. This is also where our quality assurance systems come into play. They ensure that our customers deliver 100 % flawless packaging to their customers. In short: in the production of sustainable packaging - including machine application of adhesives - the various factors must go hand in hand.
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