Cardanols as a Versatile Tool for 1K and 2K Polyurethane Systems: Non-toxic Isocyanate Blocking Agent and Minimization of Moisture Sensitivity

摘要

Cashew Nutshell Liquid (CNSL). a by-product of the AnacardiumOccidentale nut, is a non-edible natural oil widely used in epoxy coatings, friction materials and recently exploited in polyurethane systems. Its main component, 3-pentadecenyl-phenol or cardanol, can be derivatized (on the phenoxy group, aromatic ring or on side chain double bonds), introducing suitable functionalities that can further react with isocyanates, or it can be used as an efficient NCO-blocking agent, representing a valid, bio-based alternative to both phenol and nonyl-phenol. This paper describes the benefits imparted by the use of cardanol-based diols in IK and 2K formulations, including high hydrophobicity. chemical resistance and low moisture sensitivity of resulting polyurethane systems, still exhibiting good mechanical properties. The second part of paper demonstrates the applicability of cardanol as a blocking agent for isocyanate and prepolymers (based on polypropylene glycol and CNSL diols). validating the role of this unique bio-molecule as a useful performing option for the PU industry.