Low VOC Coating Systems From Novel Glycidyl Carbamate Resins

Abstract

The goal of the research presented in this dissertation was to design and synthesize novel glycidyl carbamate (GC) resins for low VOC applications and study the structure property relationships of their coatings. Primarily GC resins are synthesized using aliphatic polyisocyanate resins such as biuret and isocyanurate of hexamethylene diisocyanate. Polyisocyanate based GC resins had extremely high viscosity. Biuret glycidyl carbamate (BGC) resin was modified by replacing part of the glycidol with alcohols. The alcohol composition and the extent of alcohol composition in the resin were systematically varied. The alcohol modification reduced the resin viscosity dramatically. Performance of amine and self-crosslinked GC coatings was studied. GC resins were synthesized for binder systems for flexible primer applications using diisocyanates and combinations of linear diols and a triol. The diisocyanates, diols and triol were used to obtain GC resins. Flexibility and barrier properties of the amine crosslinked coatings were influenced by the composition of the GC resins. Water dispersible GC resins were synthesized for low or zero VOC waterborne coating applications. Non-ionic hydrophilic group, methoxy poly(ethylene glycol) (mPEG), was incorporated into the resin structure. Molecular weight and mol % of mPEG in the resin was systematically varied. Waterborne GC coatings were prepared using water-based amine crosslinker and properties of the cured coatings were studied. UV curable GC resins were made by reacting BGC, isocyanurate glycidyl carbamate (IGC), and alcohol modified IGC resins with acrylic acid. UV curable coating formulations were prepared using reactive diluents, a photoinitiator, and an amine coinitiator. Real-time FTIR (RTIR) was used to determine the degree of double bond conversion in UV curing. The performance of the UV cured coatings was studied. Finally, air drying (autoxidizable) GC resin (BGC-LOFA) was obtained by reacting BGC resin with linseed oil fatty acid (LOFA). Air drying GC coatings were obtained using common driers used for alkyd-based coatings.