Allophanate Structures as Building Blocks for Very Low Viscous Urethane Acrylates

Urethane acrylates exhibit particularly good properties as binders for UV curable resins including toughness, chemical and abrasion resistance, flexibility and weather resistance (aliphatic types). On molecular basis, hydrogen bridging is largely responsible for most of these exceflent properties but contributes to a comparatively high viscosity as well. Allophanate structures are known to have a very low viscosity compared to other isocyanate derivatives due to a lower urethane content and a flexible scaffold. Three synthetic routes towards allophanate based urethane acrylates are being introduced and discussed with regards to industrial feasibility and product properties as higher performing substitutes for established products.