Urea derivatives and their use as curatives and curative accelerators for resin systems
Bisorthohydroxy aromatic urones and their use as curatives and cure accelerators in resin systems particularly epoxy resin systems provide formulations with good outlife, low curing temperatures and desirable glass transition temperatures after curing, they are particularly useful in prepregs used in the production of components for the aerospace and wind turbine industries.
1 . 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 R 1 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 R 2 and R 3 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 R 4 is at each occurrence, independently of one or another, selected from H, NH 2 , NO 2 , 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.
2 . The process according to claim 1 wherein the curing is performed in a press.