Blocked isocyanates as alternative curing agents for epoxy-polyurethane resins based on modified vegetable oils

Abstract

Presented research shows the results of a study on the synthesis and mechanical properties of materials obtained by crosslinking polyaddition bio-products with blocked isocyanate based on toluene diisocyanate (TDI) as curing agent. Bio-resins, polyaddition product of epoxidized soybean oil and bisphenol A or hydroxylated soybean oil and low molecular weight epoxy resin, were synthesized via modern and pro-ecological modification of the synthesis of epoxies, namely, the epoxy fusion process. The obtained polyaddition product contains free epoxy and hydroxyl groups, which are suitable for the curing purposes. Material cured with Desmodur BL 1265/MPA/X in the presence of organometallic or amine catalyst (respectively: Dabco T9 and Dabco 33-LV) is characterized by mechanical properties better than the composition crosslinked without the catalyst. Additionally, there is a possibility of the synthesis of two-layer materials by chemical bonding of two different compositions via the previously unused oxirane groups of the cured ESBO_BPA or SMEG_EPR products.