Overview / Technology routes / Non-isocyanate polyurethanes (NIPU)
Non-isocyanate polyurethanes (NIPU)
Cyclic carbonates reacting with amines build polyurethanes without isocyanates or phosgene.
Overview
NIPUs form when five-membered cyclic carbonates react with amines, producing hydroxyurethane links. Wood-adhesive NIPUs have been made from sucrose, tannin, lignin and vegetable-oil carbonates.
Chemistry and bonding mechanism
Carbonates are introduced by reacting polyols with dimethyl carbonate, or by adding CO2 to epoxides. They then cure with diamines. The amine is often fossil-derived, such as hexamethylenediamine, so the whole formulation has to be checked before it is called bio-based.
Representative structures
Monomers and model units, drawn from SMILES with RDKit. Polymers are shown by a representative unit, not a full structure.
Glycerol carbonate
Bio-derivable five-membered cyclic carbonate; reacts with amines to hydroxyurethanes (NIPU).
O=C1OCC(CO)O1Sucrose
Polyol in citric acid-sucrose adhesives and sugar-based NIPU.
OC[C@H]1O[C@@](CO)(O[C@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)[C@@H](O)[C@@H]1OPosition and maturity
- Typical products
- particleboard, plywood, wood coatings
- Incumbent to beat
- pMDI and PF.
- Maturity
- Laboratory scale.
Strengths
- Avoids isocyanate exposure; hydroxyl groups formed in the cure aid adhesion.
What to watch
- Bio-based amines; catalysed cure at industrial press cycles.
Technical challenges
- Slow aminolysis means long cure times; amine cost and origin; synthesis steps.
Cross-cutting: Press time, temperature and line throughput · Renewable-content accounting · Cost per qualified bond · Comparable life-cycle evidence
Quarterly track
2026-Q4 · Sept 2026 – Nov 2026
Machine-triaged leads (0)
No machine-triaged leads above the relevance threshold.
2026-Q3 · Jun 2026 – Aug 2026
Machine-triaged leads (1)
Enhancement of tannin-based non-isocyanate bio-polyurethane resins properties with addition of waterglass and glyoxal using response surface methodology for plywood adhesives
2026-Q2 · Mar 2026 – May 2026
Machine-triaged leads (3)
A green and sustainable three-layer bamboo particleboard from chopstick waste bonded with bio-based polyurethane composite for engineering applications
“three-layer bamboo particleboard from chopstick waste bonded with bio-based polyurethane composite”
Sustainable particleboard from bamboo waste/water hyacinth/plant-based polyurethane adhesive composite: a green flame-retardant material
“Sustainable particleboard from bamboo waste/water hyacinth/plant-based polyurethane adhesive composite”
Wood modification by in situ polymerization of non-isocyanate polyurethane using biobased erythritol bis(carbonate) and polyamines
2026-Q1 · Dec 2025 – Feb 2026
Machine-triaged leads (2)
Surface interaction and adhesion behaviour of eco-friendly non-isocyanate polyurethane wood adhesives derived from upcycled polystyrene and coumarone-indene resins
“Surface interaction and adhesion behaviour of eco-friendly non-isocyanate polyurethane wood adhesives”
A bio-based non-isocyanate polyurethane adhesive with microphase-separated structure and topological entanglement to simultaneously realize enhanced cohesion and interfacial adhesion
Key literature
- Xi X., Wu Z., Pizzi A., Gerardin C., Lei H., et al. (2019). Non-isocyanate polyurethane adhesive from sucrose used for particleboard. Wood Science and Technology. doi:10.1007/s00226-019-01083-2 research
- Saražin J., Pizzi A., Amirou S., Schmiedl D., Šernek M. (2021). Organosolv lignin for non-isocyanate based polyurethanes (NIPU) as wood adhesive. Journal of Renewable Materials. doi:10.32604/jrm.2021.015047 research
- Iswanto A.H., Lubis M.A.R., Sutiawan J., Al-Edrus S.S.O., Lee S.H., et al. (2023). Latest advancements in the development of high-performance lignin- and tannin-based non-isocyanate polyurethane adhesive for wood composites. Polymers. doi:10.3390/polym15193864 review