Alkaline lignin—a woody byproduct discarded in pulp and paper manufacturing—could be key to making timber products coated with greener water-based treatments more fire-resistant – with a 5% concentration of lignin the “sweet spot” for optimal performance.
That is according to new research published in the 2024 edition of the Journal of Coatings Technology and Research. The research found that water-based intumescent acrylic coatings that used alkaline lignin had superior flame retardancy compared to those without additives.
“Based on this information, intumescent water-based coatings containing 5% alkaline lignin improves flame retardancy by promoting the formation of an ideal char layer during combustion,” the study said, adding that the researchers tested water-based acrylic resin mixed with 1%, 3%, 5% and 10% concentrations of lignin.
“The analysis results reveal that coatings containing 5% alkaline lignin were more effective in reducing flammability than those containing higher concentrations.”
The discovery comes as global pulp and paper companies partner with material scientists to create fully circular products using lignin. Earlier this year, Wood Central reported that pulp and paper companies are using the byproducts of lithium-ion batteries, asphalt, textiles, and even bio-dispersant plasticisers to “green up concrete.”
In recent years, chemists have turned to water-based treatments as global timber looks to decarbonise supply chains – including Fireshield® TimberClear, a non-combustible, water-based, clear intumescent basecoat used to protect interior timber from fire.
Last year, Wood Central reported that timber treatment specialist and modern-day wood preservation pioneer Gerry Gardiner is behind a new solution, TRU-CORE by Kop-Coat Protection Products (KCPP), which can use harvested rainwater to develop a water-based solution for Australian hardwoods, softwoods and engineered timbers.
“The use of TRU-CORE has had a significant input into decarbonising some timber treatments,” Mr Gardiner said. “In an industry with outstanding credentials, this further enhances our value to the environment.”
- Click on Wood Central’s special feature to learn more about lignin and its role in decarbonising the building and construction industry. To learn more about why the timber industry is considering water-based treatments, click on Wood Central’s story from the International Research Group on Wood Protection conference in Cairns last year.
