| 摘要 |
PURPOSE:To obtain an open-cell rigid isocyanurate foam excellent in flame retardancy and heat resistance and useful as a core material for a vacuum insulation material by expanding a mixture comprising an organic polyisocyanate and an organic polyol in a specified ratio. CONSTITUTION:The foam is prepared by expanding a mixture comprising an organic polyisocyanate, desirably an aromatic polyisocyanate more desirably monomeric diphenylmethane diisocyanate and/or polymeric diphenylmethane diisocyanate, and an organic polyol having a molecular weight of 30-3000 per hydroxyl group and an OH functionality of 2-8/mol, desirably a polyether polyol, an alkylene polyol or a polyester polyol, and having an NCO/OH equivalent ratio of 3.5-1. |
