| 摘要 |
PURPOSE:To obtain a flame-retardant polyurethane foam having improved flame-retardance and suitable for the use as a cushioning material, a heat- insulation material, a building material, etc., by adding a specific amount of a specific thermally expandable graphite to a polyurethane foam. CONSTITUTION:A thermally expandable graphite containing alkali metal and having a pH of >=4.5, preferably 4.5-8 as an aqueous dispersion having a concentration of 1wt.% is added to a polyol (aromatic polyester polyol) at a ratio to give a polyuretane foam containing 5-30wt.% of the graphite and the polyol is made to react with a polyisocyanate compound to obtain the objective flame- retardant polyurethane foam. For example, the thermally expandable graphite has an expansion degree of 50-250cm<3>/g when quickly heated at 1,000 deg.C for 10sec and is produced by contacting graphite crushed to 20-100 mesh with a mixture of 98% concentrated sulfuric acid and 60% solution of hydrogen peroxide at <=45 deg.C for 10-30min, washing the treated treated graphite with water and drying the product. |
