POLYURETHANE FOAM CORE FOR PRODUCING BLADES, IN PARTICULAR FOR WIND POWER TURBINES

摘要

Reinforced polyurethane foam obtainable by mixing polyisocyanates with compounds having isocyanate-reactive groups, propellants, and optionally catalyst and further additives to form a reaction mixture, and curing the reaction mixture, is claimed. The reaction mixture to be cured comprises hollow microspheres and/or is applied to a porous reinforcing agent, which forms two-dimensional or three-dimensional networks in the polyurethane foam. The compounds having isocyanate-reactive groups comprise polyetherol, polyesterol, chain extenders and optionally crosslinkers and aromatic polyether diols. Reinforced polyurethane foam having a density of greater than 50-300 g/l, a density-independent compressive strength of greater than 7.5x 10 -> 4>MPa (l/g) 1> .> 6>, a density-independent compressive modulus of elasticity of greater than 1.7x 10 -> 2>MPa (l/g) 1> .> 7>, a density-independent tensile strength of greater than 6.4x 10 -> 4>MPa (l/g) 1> .> 6>, a density-independent tensile modulus of elasticity of greater than 2.4x 10 -> 2>MPa (l/g) 1> .> 7>, a density-independent flexural strength of greater than 1.25x 10 -> 3>MPa (l/g) 1> .> 6>, and a density-independent flexural modulus of elasticity of greater than 1.75x 10 -> 2>MPa (l/g) 1> .> 7>, obtainable by mixing (a) polyisocyanates with (b) compounds having isocyanate-reactive groups, (c) propellants comprising water, and optionally (d) catalyst and (e) further additives to form a reaction mixture, and curing the reaction mixture, is claimed. The reaction mixture to be cured comprises hollow microspheres (1-40 wt.%) and/or is applied to a (f) porous reinforcing agent, which forms two-dimensional or three-dimensional networks in the polyurethane foam. The compounds having isocyanate-reactive groups (b) comprise (b1) polyetherol, (b2) polyesterol, (b3) chain extenders and (b4) optionally crosslinkers and (b5) aromatic polyether diols. The fraction of components (b2), (b3) and (b5) in component (b) is at least 50 wt.%, based on the total weight of component (b). An independent claim is also included for producing reinforced polyurethane foam, comprising mixing component (a) with components (b), (c), (d) and (e) to a reaction mixture and curing the reaction mixture.