Polymer formulations with chemically tunable rheological properties for the manufacture of articles composed of prepregs and composites

摘要

A polymeric formulation comprising at least one first epoxy resin having a density between 100 and 10,000 Pa·s, a blocked isocyanate, a polymer comprising hydroxy functional groups, a thermoplastic resin and a cross-linking agent, the polymer comprising hydroxyl functional groups with a hydroxyl content in the range 0.65 to 0.95 meq/g, the isocyanate-equivalents-to-polymer-OH-equivalents rate being in the range 0.60 to 1.1. The first epoxy resin is substantially semisolid at room temperature, the formulation comprising at least one second epoxy resin substantially liquid at room temperature, the first and second epoxy resins being present in a weight ratio from 60:40 to 80:20. These formulations are advantageously used for manufacturing prepregs and articles of composite material according to a dry winding process. By virtue of improved stability, a higher glass transition temperature, and a rheological profile result which can be chemically tailored to the needs of the impregnation/dry winding process.