Eco-friendly Isocyanate Blocking Agent, Cardanol: Deblocking Performances and Methods to Optimize Deblocking Temperature

摘要

Cardanol is a well-known non-edible natural oil derived from the Cashew Nutshell Liquid and an USDA certified bio-based product. Once used as a very high purity grade (NX-2026™, 3-pentadeca-dienyl-phenol) in PU prepolymers, this substance has demonstrated various benefits including favorable deblocking conditions, lower viscosity, and excellent storage stability in comparison to commonly used phenolic compounds. One of the most known deblocking methods involves the exposure to elevated temperatures, i.e. 150°C - 200°C. However, not all the substrates (e.g. plastics) and applications can accommodate such high temperatures for deblocking, thus, the possibility to optimize the deblocking conditions can be a valuable tool to further expand the applicability of 3-pentadecadienyl-phenol as a label friendly polyurethane prepolymers' blocking agents. In this study, Cardolite will present different approaches to control NX-2026™ deblocking conditions. Firstly, 3-pentadeca-dienyl-phenol blocked prepolymers are prepared starting from different diols (e.g. PPG, polyester, CNSL-based) and aromatic (MDI, TDI) and aliphatic (HDI, IPDI) isocyanates, subsequently characterized for their deblocking temperatures and used as model substrates for the study. Key factors for controlling deblocking conditions including catalysts, deblocking agents (amines, polyols), and solvents will be investigated.