Urea derivatives and their use as curatives and curative accelerators for resin systems

A process for the production of an article comprising curing a prepreg by an externally applied temperature of 60° C. to 190° C.;

• wherein said prepreg comprises:
• (a) bisorthohydroxy aromatic urone of formulae:
• wherein R1 is selected from S, SO2, SO, P, PX, N, NH, or NX, P═O(—OH), P═O(—OX), C═O, a substituted or unsubstituted linear or branched aliphatic radical, or an unsubstituted, halo substituted and/or alkyl substituted aromatic radical and n is a number from 2 to 20;
• wherein X is a substituted or unsubstituted linear or branched aliphatic radical, or an unsubstituted, halo substituted and/or alkyl substituted aromatic radical;
• wherein R2 and R3 is at each occurrence, independently of one another, selected from an alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl group, which may be substituted by a halogen atom or by a hydroxyl or cyano group;
• and
• and wherein R4 is at each occurrence, independently of one or another, selected from H, NH2, NO2, nitrile, a halogen, linear or ranched aliphatic radical, or an unsubstituted, halo substituted and/or alkyl substituted aromatic radical, and Y=1 to 3;
• and wherein
• wherein the bisorthohydroxy aromatic urone comprises 0.1 to 20 wt % of said prepreg;
• further comprising a fibrous reinforcement material selected from a woven fabric, a multi-axial fabric, individual fibre tows, and mixtures thereof.