News Coatings Technologies
Pulp mill residues yield flame-retardant bio-based wood adhesive
Researchers have developed a fully bio-based wood adhesive from kraft pulp mill side-streams that combines competitive bond strength with flame-retardant and heat-insulating properties. Life cycle assessment confirms a lower environmental impact than commercial polyurethane and polyvinyl acetate alternatives.
Wood-based adhesives are used extensively but often face concerns regarding health, sustainability and their dependence on fossil raw materials. A recent study addresses this challenge by valorising industrial side-streams from kraft pulp mills, which are currently incinerated, into a fully bio-based wood adhesive. The approach targets both environmental impact and industrial productivity, as it also enables increased pulp production capacity.
The adhesive achieved a lap-shear strength of 7.69 MPa, placing it on a par with commercial alternatives. In addition to bond strength, the material exhibited good heat-insulating and flame-retardant properties, opening potential applications where fire safety is critical. Solid-state ¹³C NMR spectroscopy of ¹³C-enriched samples, combined with DFT calculations, revealed that the furfural aldehyde moiety is fully incorporated into the aromatic structure of the adhesive matrix, providing a molecular explanation for the observed performance.
Event Tip: EC Conference Frontiers in Wood Coatings
TheEC Conference Frontiers in Wood Coatings, formerly the Wood Coatings Congress, has established itself as the international reference platform for scientific and technical exchange in the field of wood coatings. Over the course of two intensive days in Amsterdam, the conference will bring together stakeholders from across the value chain — from resin and additive producers to leading research institutes, coating manufacturers, and end-use industries — to discuss the latest advances in formulations, application processes, and sustainable solutions.
Life cycle assessment against commercial adhesive systems
The environmental performance of the new adhesive was benchmarked against commercial polyurethane and polyvinyl acetate systems using life cycle assessment (LCA). The bio-based adhesive showed lower environmental impacts in 13 to 15 of the 16 impact categories considered, indicating a broad sustainability advantage across the full life cycle.
The authors emphasise that the strategy demonstrates how forestry-derived industrial side-streams — otherwise used only for their heating value — can be converted into higher-value products that substitute for problematic petrochemical-based materials. Beyond providing an environmentally favourable alternative in the adhesives market, the approach illustrates a broader concept for valorising kraft pulp mill by-products such as prehydrolysis liquors and lignin, with potential implications for future formulations in wood-based coatings and adhesives.
Source: Schick, L. W. et al., Flame-retardant wood adhesive prepared from pulp mill residues. Green Chem. 28, 13253–13264 (2026).
