Resin composition for preparing a thermoplastic polymer matrix

A resin composition for preparing a thermoplastic polymer matrix, comprising:

• a) a polyisocyanate with an isocyanate group functionality of 1.7 to 3.0;
• b) an isocyanate-reactive component with an isocyanate-reactive group functionality of less than 2.2, which comprises an aspartate having a structure of formula I and 0 to 50 weight % of a further isocyanate-reactive compound;
• wherein the isocyanate-reactive component is in a liquid form at 5° C. to 25° C., and the aspartate having a structure of formula I is:
• wherein X is an aliphatic residue, R1 and R2 are each independently an organic group that is not reactive to isocyanate groups under normal pressure and at a temperature of less than or equal to 100° C., and n is ≥2;
• the isocyanate-reactive group of the further isocyanate-reactive compound is one or more of primary amino groups, secondary amino groups and hydroxyl group containing active hydrogen;
• and
• c) an additive;
• wherein the molar ratio of isocyanate groups to isocyanate-reactive groups of the resin composition is of 0.5:1 to 2:1.