Technical challenges

Water and moisture resistance

Most bio-binders are rich in hydroxyl, amine and carboxyl groups that absorb water. Dry strength is easy to reach; wet, cyclic and boil tests are where candidates fail.

• Report dry and wet results separately and name the pretreatment (for example EN 314-1 bonding-quality pretreatments, or soaking and boiling cycles).
• The service class matters. A binder that suits interior furniture board can still be unsuitable for humid or exterior use.

Ask: Which standard and pretreatment was used, and does the product class require it?

Press time, temperature and line throughput

Panel lines are tuned to fast-curing UF and pMDI. Slower cure or higher press temperature lowers output and raises energy use, which can cancel out a cheaper feedstock.

• Express press time per mm of board thickness at a stated press temperature and compare it with the incumbent on the same line.
• High-moisture binders can cause steam blows. Account for the moisture content of resinated particles or veneer.

Ask: What press factor (s/mm) and temperature did the test use, and how does it compare with UF on the same line?

Viscosity, solids content and pot life

Protein and tannin solutions become very viscous at the solids content needed for low water input. Spraying or roller application, and storage stability, limit what can be used.

• Report viscosity together with solids content, temperature and age. One viscosity figure on its own cannot be compared.

Ask: What were the solids content, viscosity and pot life under plant conditions?

Formaldehyde and VOC emissions

From 6 August 2026, REACH Annex XVII entry 77 limits formaldehyde release from furniture and wood-based articles placed on the EU market to 0.062 mg/m³ under its test conditions. "Formaldehyde-free" claims need emission data, not only a recipe.

• Hardeners such as hexamine, and some crosslinkers, release formaldehyde. Natural wood also emits small amounts.
• Formaldehyde, other VOCs and climate impact are separate questions. A low-carbon binder can still emit VOCs.

Ask: Was emission measured with a chamber method on finished boards, and against which limit?

Renewable-content accounting

A bio-based binder can be crosslinked with a fossil crosslinker, and a mass-balance claim is not the same as measured bio-based carbon. The basis must be stated.

• Distinguish binder-level from whole-formulation renewable content, including crosslinkers, catalysts, extenders and additives.
• Measured bio-based carbon (for example by radiocarbon methods) and mass-balance attribution answer different questions.

Ask: What share of the whole formulation, on a dry basis, is renewable, and how was it determined?

Feedstock variability and supply

Lignin, tannin and protein side streams vary with source, season and process. Panel producers need consistent specifications in large volumes.

• A single laboratory batch does not show supply. Look for specifications, multiple lots and contracted volume.

Ask: How many lots were tested, and what volume can be supplied to specification?

Biological durability and ageing

Protein and carbohydrate bond lines can support mould growth and lose strength over time. Accelerated ageing data are rarely reported.

Ask: Were mould resistance or ageing tested, and was a biocide needed?

Cost per qualified bond

Price per tonne of binder is misleading. Compare total bonding cost for the same qualified product, covering dosage, solids, additives, press time, energy, rejects and capital changes.

Ask: What is the cost per m³ of qualified board compared with the incumbent on the same line?

Comparable life-cycle evidence

Claims of carbon benefit need a functional unit (for example 1 m³ of a defined board class), a system boundary and an equivalent incumbent product. Feedstock origin on its own does not prove a benefit.

Ask: What functional unit, boundary and comparator does the LCA use, and was it reviewed?

End of life and recyclability

Debondable or reversible binders could enable panel recycling. Laboratory joint recovery is far from panel-scale recycling economics.

Ask: Was recovery shown on panels, with solvent and energy use accounted for?