100% Bio-Based Wood Adhesives: Industrial Challenges and Role of the SUSBOARD Project

Engineered wood panels, particularly particleboard (PB) and medium-density fibreboard (MDF), are widely used materials in the global furniture and construction sectors. While the primary constituent of these panels, wood, is a renewable resource, the adhesives used to bind these fibres into structural boards are still predominantly derived from fossil resources.

The EU-funded project SUSBOARD addresses this challenge by developing a 100% bio-based, formaldehyde-free adhesive system capable of meeting industrial manufacturing standards. To illustrate the technical focus and lifecycle impact of this work, the project has published a new interactive infographic.

The SUSBOARD approach, ©SUSBOARD

This article examines the industrial relevance of replacing petrochemical resins, the technical challenges associated with bio-based alternatives, and how these developments relate to European climate and sustainability objectives.

Engineered wood panels are produced at large industrial scale. In Europe, the industry manufactures approximately 60 million cubic meters (m³) of particleboard and MDF annually.  These materials play an essential role in furniture production, interior construction, and building components.

© Market Data Forecast Analysis 

Producing panels at this scale requires substantial quantities of adhesives. Estimates indicate that 90% to 95% of these industrial wood adhesives are formaldehyde based. The industry relies primarily on synthetic thermosetting resins such as urea-formaldehyde (UF), melamine-urea-formaldehyde (MUF) phenol-formaldehyde (PF), and pMDI.

These resins remain dominant because they combine relatively low cost, rapid curing, and strong mechanical bond strength. However, their widespread use also suggests that large volumes of fossil derived chemicals are embedded in wood products. This reliance raises two key concerns: greenhouse gas emissions linked to petrochemical production and potential health impacts associated with fossil-based adhesives.

The production of petrochemical feedstocks and synthetic resins requires energy-intensive processes that generate greenhouse gas emissions. Within corporate greenhouse gas (GHG) accounting frameworks, emissions are divided into three scopes:

• Scope 1: Direct emissions from owned or controlled sources
• Scope 2: Indirect emissions from purchased electricity
• Scope 3: Indirect emissions across the value chain, including raw material production and end-of life treatment

For furniture and wood panel manufacturers, Scope 1 emissions often represent the largest share of their overall carbon footprint. Wood products can act as a temporary carbon storage, as trees absorb carbon during growth. However, adhesives, particularly fossil-derived ones, remain a major environmental hotspot in wood-based panel production due to emissions associated with the petrochemical supply chain, often followed by the energy required during the board pressing process.

Reducing these fossil-based components therefore represents an important opportunity for manufacturers seeking to reduce their upstream emissions and progress towards climate targets.

Traditional synthetic resins are raising concerns related to indoor air quality and occupational exposure.  During curing in the hot press, and over the lifespan of the product, these adhesives emit formaldehyde.

Formaldehyde is classified as a human carcinogen by the International Agency for Research on Cancer (IARC). Exposure risks are particularly relevant in industrial production environments and can also contribute to indoor air pollution in homes and workplaces.

European regulations, limit the amount of formaldehyde released from wood-based products. Nevertheless, replacing formaldehyde-based resins with safer alternatives remains a long-term objective for the sector.

Replacing highly optimized synthetic resins with 100% bio-based alternatives presents several scientific and engineering challenges.

Researchers have investigated a range of natural binders derived from materials such as lignin, starch, soy proteins, and tannins, However, achieving a fully bio-based formulation suitable for industrial use requires meeting strict manufacturing conditions.

PB and MDF Boards, © Shutterstock

Modern particleboard and MDF production lines operate at high speeds, pressing wood particles or fibres at temperatures typically between 180°C and 220°C. Under these conditions, synthetic resins cure very rapidly, enabling efficient large-scale production.  Many natural biopolymers, however, react more slowly, which can require longer pressing times or higher temperatures.  This reduces manufacturing efficiency and increase energy consumption.

Furthermore, another challenge relates to viscosity and solids content. Industrial adhesives must maintain a manageable viscosity while possessing a high solids content, often above 60% for synthetic resins, to be sprayed evenly onto wood fibres. Bio-based adhesives, particularly those based on high-molecular-weight proteins or starches, tend to become highly viscous at elevated concentrations.  Dilution with water can create additional challenges during pressing, including internal steam ruptures sometimes referred to as board blowouts.

Durability is also essential. Panels and furniture must maintain structural integrity under varying humidity and environmental conditions. Earlier bio-based adhesive formulations have sometimes shown limited resistance to moisture, which can lead to bond degradation over time.

Finally, achieving the necessary mechanical strength has historically required retaining a small percentage of fossil-based cross-linkers and amine components. Previous research initiatives, such as the EU-funded SUSBIND project, successfully replaced a large share of adhesive components with renewable materials, surpassing 80% renewable content. However, replacing the remaining petrochemical fraction without compromising the performance remains a significant challenge.

The SUSBOARD project focuses on addressing this remaining challenge. Building on the progress achieved in SUSBIND, the consortium is developing and applying a fully bio-based amine component.

PB and MDF Boards, © European Commission

The objective is to develop an adhesive that replicates the curing behaviour, viscosity, and structural performance required in industrial manufacturing while relying entirely on renewable raw materials.

According to the project targets defined under the Horizon Europe framework, successfully scaling this 100% bio-based adhesive to multi-ton industrial levels is projected to yield a reduction in the carbon footprint of wood boards by up to 30%.

This technological development also supports broader European policy objectives:

• The European Green Deal: By contributing to the decarbonization of the energy-intensive manufacturing sector, fully bio-based adhesives can support Europe’s goal of achieving climate neutrality by 2050.
• The Circular Economy Action Plan: Bio-based adhesive systems may facilitate safer recycling and end-of-life processing of wood-based materials.
• The Zero Pollution Action Plan: Eliminating formaldehyde from adhesive formulations could help improve air quality in both industrial environments and indoor spaces.

Developing new industrial materials requires extension testing across laboratory, pilot and industrial environments.  The SUSBOARD consortium is currently advancing this bio-based adhesive technology through validation stages, including testing in wood panel manufacturing and the development of a modular furniture prototype.