| 摘要 |
A low-density rigid reinforced polyurethane is provided to solve the problems occurring when using water and carbon dioxide for reducing the density of polyurethane, such as degradation of physical and mechanical properties, generation of voids or air bubbles, and a decrease in gel time and release time. A low-density fiber-reinforced polyurethane comprises a reaction mixture of: (1) an isocyanate-reactive component containing (a) a polyol having a hydroxyl functionality of about 3-8 and OH number of greater than 200, (b) a catalyst, (c) a surfactant, (d) optionally, a crosslinking agent, (e) optionally, water, and (f) optionally, dissolved carbon dioxide; (2) an isocyanate component containing (a) an organic polyisocyanate and (b) optionally, dissolved carbon dioxide; and (3) a fiber reinforcing agent, wherein carbon dioxide exists in at least one of the isocyanate-reactive component and the isocyanate component in a total amount of 0.3-2.0 g/l.
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