| 摘要 |
PURPOSE: Hard polyurethane foam is provided to able to maintain physical properties like impact resistance, environment-friendliness, moldability, dimensional stability, flame retardance, etc by using bio-polyol having a specific number of functional groups, a specific value of hydroxy group, a specific viscosity, etc. CONSTITUTION: Hard polyurethane foam comprises polyol comprising bio polyol, and isocyanate. A core density of the hard polyurethane foam is 150 kg/m^3 or lower, a compressive strength is 2.0 kg/cm^2 or higher, a flexural strength is 3.0 kg/cm^2 or higher, an elongation is 40% or higher, a dimensional stability is -2.0% or less at 30 °C, 24 hr, and 3.0% or less at 70 °C, 24 hr. The biopolyol comprises 10-60 weight% of natural oil, 10-60 weight% of a polyfunctional active hydrogen-containing compound, 0.1-1.5 weight% of a catalyst, and 20-70 weight% of alkylene oxide. A number of functional groups is 3 or higher, a hydroxyl value of KOH/g is 200-600 mg, and a viscosity 25 25°C is 2,000-25,000. |
