Study On Latent Curing Agents In Polyurethane

In this paper, 3-hydroxyethanyl-1,3-oxazolidine, 2-isopropyl-3-hydroxyethan -yl-1,3-oxazolidine, 2-phenyl-3-hydroxyethanyl-1,3-oxazolidine were synthesized. These oxazolidine derivatives can be used as latent curing agents in single component moisture curable polyurethane (PU) system to improve PU material properties.In this paper, these oxazolidine derivatives were synthesized from carbonyl group compounds (formalin, isobutyl aldehyde or phenyl aldehyde) andβ-hydroxyl ethanolamine (diethanolamine) in azeotropic solvents (cyclohexane or methyl-benzene) at the given temperature. The azeotropic solvents boiled to remove water formed in the addition-condensation process from the reactant mixtures. The products were purified by vacuum distillation. Orthogonal experiment design was used to optimize experimental factors: solvent amount, raw material ratio, temperature and reaction time. Fixing diethanolamine dose 24mL, the best conditions of synthesis of 3-hydroxyetha-nyl-1,3-oxazolidine are cyclohexane dose 20mL, formalin dose 19.2mL, reation temperature 40℃and reaction time 1 hour; the best conditions of synthesis of 2-isopropyl-3-hydroxyethanyl-1,3-oxazolidine are cyclohexane dose 20mL, isobutyl aldehyde dose 22.7mL, reaction temperature 50℃and reaction time 0.5 hour; the best conditions of synthesis of 2-phenyl-3-hydroxyethanyl-1,3-oxazolid -ine are methylbenzene dose 20mL, phenyl aldehyde dose 25.4mL, reaction temperature 60℃and reaction time 1 hour. The addition-condensation reaction...