Lignin and softwood tannins a renewable replacement for phenol
A leading provider of renewable solutions in packaging, biomaterials, wood and paper has found use for a component of wood traditionally discarded as waste.
Despite making up between 20 and 30 per cent of the composition of wood, lignin has long been dismissed by the pulp and paper industries as an unwanted by-product. But that could change following the launch of a new bio-based lignin product, Lineo.
Created by Stora Enso, the product recognises lignin’s potential as a sustainable replacement for the oil-based phenolic materials conventionally used in resins for plywood, oriented strand board (OSB), laminated veneer lumber (LVL), paper lamination and insulation material, and as a disinfectant in dilute form.
Executive Vice President of the Stora Enso biomaterials division, Mr Markus Mannström, described the advantages of lignin as being a non-toxic raw material with a traceable origin and stable cost structure.
“We believe that everything made from fossil-based materials today can be made from a tree tomorrow,” he said.
Since 2015, Stora Enso has been producing lignin out of its Finland-based mill which, with a capacity of 50,000 metric tonnes per year, makes it the largest producer of its kind in the world. In addition to selling Lineo to companies as an environmentally friendly replacement for phenol, they are actively looking at other possible applications for what they consider to be a versatile raw material with huge untapped potential.
Researchers are developing an industrial production method for the extraction of the large quantities of water-soluble tannin-polyphenols found in Finnish softwood bark, which have been shown to provide a successful substitute to the fossil and toxic phenol compounds typically used in the production of glues.
An estimated three million tonnes of softwood bark are produced as a by-product of the Finnish forest industry each year, most of which is either burned or used as a pulp mill energy source.
Putting this bark to use as a renewable compound in the glue production process is therefore not only good news for the environment, but will also help to maximise value from Finnish forest biomass and create a new business stream.
These efforts are being conducted by the SusBinders project team, a collaboration between VTT Technical Research Centre of Finland, the Natural Resources Institute Finland (Luke) and the South-Eastern Finland University of Applied Sciences (Xamk).
The use of tannins for glue applications has huge market potential, considering that phenol-based glue resins, which are mainly used as binding agents in the production of plywood and laminates, have an annual global market value of EUR 10 billion, or more than AUD 15 billion, which equates to around four million tonnes.
The researchers are looking at ways to optimise the extraction process and assess the suitability of the tannins for various glue applications, as well as analysing the technical and economic suitability and carbon footprint of the processes and products involved.