摘要 |
<p>Flexible resilient flame-retardant and intumescent polyurethane foam is prepared from a reaction mixture comprising a polyester polyol, an organic polyisocyanate, a blowing agent, a surfactant, a catalyst, a melamine derivative and a flame-retardant; the melamine derivative has one or more hydrogen atoms replaced by a methylol and or lower alkoxymethyl group, the amount of flame-retardant is 20-60 parts by weight 100 parts by weight of the polyester polyol and hydrated alumina is also included in the reaction mixture. In a preferred embodiment, the hydrated alumina is predispersed in a mixture comprising the melamine derivative, the flame retardant and a low-viscosity linear polyester polyol.</p> |