Two-component UV-curable waterborne CO2-based polyurethane dispersion with outstanding flexibility

A series of two-component UV-curable waterborne CO₂-based polyurethane dispersions (UV-PUDs) with excellent flexibility and mechanical strength were synthesized from poly(propylene carbonate) diol (PPCD), isophorone diisocyanate (IPDI), 2,2-bis(hydroxymethyl) propionic acid (DMPA), 2-hydroxyethyl acrylate (HEA), pentaerythritol triacrylate (PETA) and 1,4-butanediol (BDO). One component was UV-curable waterborne polyurethane terminated by HEA and PETA (molar ratio 1:1), and the other component was linear waterborne polyurethane. The content of the UV-curable component in UV-PUD was 15%, 30%, 45%, 60%, and 100% (weight content). The obtained cured films exhibited superior flexibility without loss of tensile strength, accompanied by excellent acid and alkali resistance. In particular, the dried UV-PUD films without curing showed good mechanical properties.