Fully water-blown polyisocyanurate-polyurethane foams with improved mechanical properties prepared from aqueous solution of gelling/ blowing and trimerization catalysts

Abstract

AbstractFully water-blown polyisocyanurate-polyurethane (PIR-PUR) foams with improved mechanical properties have been prepared using aqueous solutions of metal-ammonia complex, Cu(Am) or Zn(Am), as gelling/blowing catalysts and potassium octoate (KOct) solution in diethylene glycol as a trimerization catalyst. Two catalyst mixtures, Cu(Am)+KOct and Zn(Am)+KOct, were obtained as homogeneous aqueous solutions. In comparison to commercial catalyst system, DMCHA+KOct (DMCHA = N,N-dimethylcyclohexylamine), Cu(Am) and Zn(Am) could be miscible with KOct solution and water easier than DMCHA. This miscibility improvement led Cu(Am)+KOct and Zn(Am)+KOct to show faster catalytic reactivity in PIR-PUR foam reactions than DMCHA+KOct. All obtained PIR-PUR foams showed self-extinguishing properties and achieved HF1 materials. However, PIR-PUR foams prepared from Cu(Am)+KOct and Zn(Am)+KOct at NCO:OH ratio of 2:1 had suitable density for industrial applications and showed higher compressive strength than that prepared from DMCHA+KOct. These foams have high potential to apply as insulations for constructions, core laminates in wall panel or storage tanks.