12/14/2009, Düsseldorf / Germany


The CO2 footprints of adhesives


Keeping those windows tight!

A gas that leaves a footprint? What’s that all about and what has it got to do with adhesives? Well, results from the German Product Carbon Footprint (PCF) pilot project have, for the first time, revealed how much in the way of greenhouse gas emissions is connected to the manufacture of joint sealants for window frames and laminating adhesives – and what percentage of emissions can be cut through their usage. The ‘Carbon Footprint’ is a measure of all the greenhouse gas emissions that occur during the lifecycle of a product.

Greenhouse gases, global warming, climate change they are all part of the same ominous chain reaction confirmed beyond reasonable doubt as a real phenomenon by scientific investigations. Arresting climate change is just about the most difficult challenge ever to confront the human race. So-called CO2 footprints can reveal how climate-compatible goods and services are, and where emissions can be reduced. As part of the German Product Carbon Footprint (PCF) pilot project, Henkel has calculated how much in the way of greenhouse gas emissions is associated with the manufacture of window frame joint sealants and laminating adhesives – and how much more of these emissions can be cut through their usage. These are the first analyses relating to these product categories.

Joint sealing compounds
During the heating season, houses and similar buildings lose a large proportion of their heating energy through their windows. How much depends not only on the windows themselves, for the joints between their frames and the masonry are also critical locations. Joint sealants of polyurethane, silicone and other materials protect such buildings from moisture penetration from the outside. On the inside, they prevent the escape of warm air and the loss of heating energy. Provided, of course, that the seals remain intact.

For the first time, Henkel has calculated how much greenhouse gas is released with the manufacture of three typical window sealants. The product lifecycle includes the use phase. Consequently, the experts also investigated the extent to which these seals can protect against unnecessary energy loss and so contribute to reducing the discharge of climate-harming gases.

Conclusion: Depending on the material, the average service life of sealing compounds for such applications ranges from 10 to 20 years; the service life of a window can easily be 40 years or more. If high-quality, long-life sealing compounds are used and the joints are regularly maintained, up to 1,000 times more in emission volumes can be saved over the lifetime of a window than are caused by the manufacture of the sealing compounds in the first place. The calculations show how important timely renewal of the window seals is in order to save significantly in heating costs.

Laminating adhesives
Food packages and other flexible air- and water-tight forms of packaging usually consist of several films bonded together as a composite, also known as laminate. The bonding agents required for this are known as laminating adhesives. Under the brand name Liofol, Henkel manufactures various types of laminating adhesive and distributes them to industrial customers around the world. These then use them to manufacture their multi-film packaging sheets on large laminating machines.

Basically, there are three categories of laminating adhesive: solvent-containing, solvent-free and water-based. The type of adhesive has a direct effect on what laminating process is used and the associated greenhouse gas emissions. Consequently, Henkel decided to calculate the CO2 footprints of all three adhesive categories with inclusion of the laminating process itself in these analyses.

Conclusion: Of the three adhesives investigated, the solvent-free type has the smallest CO2 footprint. Solvent-free laminating adhesives also score highly through, in particular, their low-energy and low-cost application during the actual laminating process. This constitutes a major argument for a technology change from solvent-containing or water-based systems to their solvent-free counterparts. However, seen overall, the proportion of emissions associated with the adhesives per se in the case of food packaging only constitutes a very small percentage of the CO2 footprint of the manufactured item.
Experience gained from the PCF pilot project
The results show that calculations of CO2 footprints provide a good indication of the climate compatibility of products and processes. Such analyses can reveal what raw materials and process steps give rise to particularly high emissions and where potential improvements lie. They therefore support the move toward innovative, sustainable consumption. An important prerequisite for this is, however, that such insights are properly and understandably communicated. Merely quoting figures is not enough. In addition, CO2 footprints ignore other environmental effects such as are registered by more comprehensive lifecycle analyses. In order to achieve a complete ecological assessment, further environmental categories must be taken into account.

There is still no internationally harmonized method for the determination of CO2 footprints – the undisputed key to achieving reliable comparability. However, solid basic methodologies are available which should facilitate harmonization within the next few years. What is important for the overall assessment of climate compatibility is that the application or use phase of the products investigated also be included in the analyses. In the case of window joint sealants, this extends over the lifetime of the frame sealed against the masonry with such products to create a draft-tight joint. In the case of laminating adhesives, it is the laminating process, i.e. the bonding together of multiple film layers to create the package that constitutes the application phase.

Henkel AG & Co. KGaA