Glyoxal, 5-HMF, furanics and bio-based epoxides that replace formaldehyde or fossil crosslinkers.
Overview
A binder is often bio-based while its crosslinker is not. This route tracks the crosslinker itself, under two tracks. Track A is renewable feedstock substitution for established isocyanate, epoxide or aldehyde chemistry. Track B is new reactive chemistry whose functional role must first be demonstrated.
Glyoxal-based urea resins (UG), 5-HMF resins and furfuryl-alcohol systems are the main aldehyde alternatives. PAE and pMDI remain the incumbent fossil crosslinkers.
Chemistry and bonding mechanism
Glyoxal is a non-volatile dialdehyde. It is less reactive than formaldehyde, so press times are longer and water resistance is usually lower unless it is combined with other components.
5-HMF carries an aldehyde on a furan ring that also bears a hydroxymethyl group. It can react with phenolics, amines and itself, but it is less stable and more expensive than formaldehyde.
Representative structures
Monomers and model units, drawn from SMILES with RDKit. Polymers are shown by a representative unit, not a full structure.
Glyoxal
Non-volatile dialdehyde used as a formaldehyde substitute (UG, lignin-glyoxal, tannin-glyoxal).
O=CC=O
5-Hydroxymethylfurfural (5-HMF)
Sugar-derived furanic aldehyde; candidate aldehyde for formaldehyde-free phenolic and amino resins.
O=Cc1ccc(CO)o1
Furfuryl alcohol
Furanic co-reactant in tannin-furanic systems; self-condenses under acid.
OCc1ccco1
Urea
Amino co-monomer of UF resins; also paired with glyoxal in UG resins.
NC(N)=O
Epichlorohydrin
Precursor of the azetidinium groups in PAE resins, the common crosslinker for soy adhesives.
ClCC1CO1
Hexamine (hexamethylenetetramine)
Hardener for tannin and lignin resins; it is itself a formaldehyde-releasing compound.
C1N2CN3CN1CN(C2)C3
Position and maturity
Typical products
particleboard, plywood, fibreboard
Incumbent to beat
Formaldehyde in UF, MUF and PF; pMDI for OSB and formaldehyde-free particleboard.
Maturity
Glyoxal is industrial as a chemical; UG panel binders are laboratory to pilot. 5-HMF supply is approaching first dedicated plant scale.
Strengths
Some systems are drop-in candidates for existing resin chemistry.
What to watch
5-HMF plant commissioning and product specifications; UG and lignin-glyoxal panel trials.
Technical challenges
Replacing formaldehyde with another aldehyde does not prove low toxicity or low emissions; each needs its own assessment.
Cost and supply of new intermediates; slower cure.
A formaldehyde-free dynamic polyimine resin made by Schiff-base polymerization was used to glue wood fibers into a remoldable, degradable, recyclable wood-based composite film.
“a formaldehyde-free and dynamic adaptive polyimine (PI) resin linked by reversible imine bonds was synthesized using a Schiff-base polymerization reaction”
machine-triagedresearchOct 2026· Industrial Crops and Productstitle only
5-HMF supply: ResiCare and Axens enter exclusive talks
Michelin ResiCare announced exclusive negotiations with Axens on 8 July to license and deploy its 5-HMF technology, developed with IFPEN. A first unit of about 3,000 t/year at Péage-de-Roussillon is scheduled to start in early 2027.
Editorial interpretation: a dedicated 5-HMF supply would matter for aldehyde-type resins that avoid formaldehyde. The capacity is for a chemical intermediate, not adhesive.
Limitation: Talks, not a concluded deal; plant not yet operating. No wood-panel formulation, emissions, cost or LCA data in this release.
Sourced facts (7) and gaps
Geography
France located in Péage-de-Roussillon, France(Paragraph 5, announcement)
Milestone
entered into exclusive negotiations have entered into exclusive negotiations for a partnership(Summary bullet 1, announcement)
derived from plant-based resources — basis: Supplier statement; feedstock not specified renewable alternatives derived from plant-based resources(Paragraph 4, announcement)
Application
resins and adhesives — basis: General use; no wood product named can be used to develop resins and adhesives as well as bio-based polymers(Paragraph 2, announcement)
Status
Start-up is scheduled for early 2027 Start-up is scheduled for early 2027(Paragraph 5, announcement)
Capacity
3,000 — unit: tonnes per year; basis: First planned unit; start-up early 2027; status: announced; product: 5-HMF (chemical intermediate, not adhesive) with a capacity of approximately 3,000 tonnes per year(Paragraph 5, announcement)
Glyoxal-urea co-condensation adhesive with starch and chitosan gave plywood bonding strength above the Chinese standard after cold and hot water immersion.
“a co-condensation method was employed to prepare glyoxal-based co-condensation adhesive incorporating starch and a small amount of chitosan as synergistic reinforcing agents”
machine-triagedresearch23 Mar 2026· Wood Material Science & Engineeringtitle only
Particleboard bonded with gum rosin-modified maleic anhydride and polymeric isocyanate was evaluated for adhesion performance and hydrolytic stability.
machine-triagedresearchMar 2026· Composites Part B: Engineeringtitle only
Aldehyde-functionalized straw microparticles and Bio-AM form a synergistic interfacial bonding network giving a formaldehyde-free bio-adhesive with good wet shear strength and low global warming impact.
“formaldehyde-free, wet-durable wood bonding”
machine-triagedresearchJan 2026· Journal of Renewable Materialstitle only
Describes formaldehyde-free alcohol-based wood adhesives prepared by ring-opening metathesis polymerization, reported with high bonding strength and water resistance.
machine-triagedresearch13 Jan 2026· Wood Science and Technology
Flax fiber composites with epoxy or bio-based polyfurfuryl alcohol matrices were bonded to spruce LVL using melamine-urea-formaldehyde and polyurethane adhesives, then tested mechanically and at 35–85% relative humidity.
“Reinforcement composites using conventional epoxy and bio-based polyfurfuryl alcohol matrices were bonded to the lumber with structural wood adhesives”
Key literature
Despres A., Pizzi A., Vu C., Delmotte L. (2009). Colourless formaldehyde-free urea resin adhesives for wood panels. European Journal of Wood and Wood Products. doi:10.1007/s00107-009-0344-yresearch
Abdullah U.H.B., Pizzi A. (2012). Tannin-furfuryl alcohol wood panel adhesives without formaldehyde. European Journal of Wood and Wood Products. doi:10.1007/s00107-012-0629-4research
Solt P., Konnerth J., Gindl-Altmutter W., Kantner W., Moser J., et al. (2019). Technological performance of formaldehyde-free adhesive alternatives for particleboard industry. International Journal of Adhesion and Adhesives. doi:10.1016/j.ijadhadh.2019.04.007review
Gui C., Wang G., Wu D., Zhu J., Liu X. (2013). Synthesis of a bio-based polyamidoamine-epichlorohydrin resin and its application for soy-based adhesives. International Journal of Adhesion and Adhesives. doi:10.1016/j.ijadhadh.2013.03.011research
Huang J., Li K. (2007). A new soy flour-based adhesive for making interior type II plywood. Journal of the American Oil Chemists' Society. doi:10.1007/s11746-007-1162-1research