At present, many building and construction products rely on the use of traditional formaldehyde-based chemistry to produce items such as wood panels, furniture, and insulation material.
However, due to the European Chemicals Agency's classification of formaldehyde as carcinogenic, the potential risks and drawbacks of this technology have come under scrutiny. Regulations are becoming increasingly stringent, with some people even predicting a complete ban on formaldehyde in the near future. What if there were a binder that possessed all the technical qualities of traditional binders, but made completely out of biobased raw material and was free of formaldehyde.
The Challenge: Glued wood products rely on toxic chemicals
Our furnishings, inner walls and insulation still heavily rely on fossil-based binders. With many of them also containing potentially harmful chemicals to ensure adequate performance, it becomes clear that we need to look out for healthier and more sustainable alternatives.
– Traditionally used raw materials like phenol and formaldehyde are toxic chemicals. Not only do they impose risks on the working environment during production, but they also affect the end user’s indoor air quality, says Heikki Lotti, Sales Manager at Stora Enso.
The rapidly increasing interest for using biopolymers from renewable resources has led to significant R&D developments toward the use of biopolymers in binders. This is where lignin, the natural glue in plants, has obtained much traction due to its phenolic structure. But without the toxicity that phenol has. This pulp side-stream and renewable raw material has been found to be particularly effective in substituting phenol in the synthesis of phenolic resins – thus getting rid of toxic components in binders and adhesives.
– Initially, Stora Enso was developing binder solutions that partially replaced fossil-based raw materials with lignin. As the continuation of that work, we wanted to find a solution that would be completely bio-based, Lotti explains.
The Solution: NeoLigno®, a bio-based binder made from lignin
After developing a binder where formaldehyde and phenols were partially replaced, Stora Enso was able to develop NeoLigno®, a lignin-based binder and a bio-based cross-linker.
– By this further development of the binder system, we were able to completely overcome the use of these chemicals, Lotti specifies.
A key benefit of Neoligno® is that it can be run in an existing production line. According to Stora Enso’s senior specialist Sara Fäldt, this is a major advantage in the complex and advanced production process of particle board.
– We want to highlight that no major extra equipment or modifications are required with this new binder. It is basically a plug and play solution.
In addition, the workability and the properties of the end-product are also very similar to traditionally used binders.
– Let’s use particle board as an example. After the panel has been produced, you need to be able to drill it, put veneer or an edge band on it, and to cut and to sand it. A particle board using NeoLigno® works very much like a standard particle board, fulfilling all requirements, Fäldt points out.
According to Fäldt, a significant advantage for users of NeoLigno® is that they will be able to offer their customers a bio-based product. Even though wood-based panels already are very sustainable, the situation is that currently used binders, making up to 10 % or even more of a panel, are still fossil-based.
– Being able to replace the fossil-based binder with a bio-based alternative is like a jackpot for panel manufacturers, Lotti illustrates.
As scientists are unearthing new health issues around essential building block chemicals for binders, legislation around like formaldehyde and isocyanate, the as a binder becomes increasingly strict. The International Agency for Research on Cancer already classifies formaldehyde as a confirmed human carcinogen, and the European Union as a presumed human carcinogen. With each reduction of the permissible threshold limit values, companies relying on traditional binders need to find alternatives to remain viable.
As companies increasingly recognize their duty to act responsibly towards the planet and future generations, she has witnessed how they are eager to test NeoLigno® firsthand.
– We're proud to be at the forefront of offering sustainable alternatives. Through our upcoming life cycle analysis, we are able to confirm significantly reduced environmental and health impacts compared to preceding products, Fäldt concludes.
Source: Stora Enso