Process for the preparation of prepregs, and the reinforced composite materials which can be obtained therewith

Claim 1

A process for the preparation of prepregs comprising the steps of (i) impregnating a reinforcing material with a liquid, solvent-free composition containing (a) an epoxide resin having on averaage more than one oxirane group, (b) a non-epoxide containing photopolymerizable acrylic ester having at least one group of the formula CH 2 ═C(Q 3 )COO-- wherein Q 3 is a hydrogen, chlorine or bromine atom or C 1 -C 4 alkyl, (c) a heat-activable curing agent for component (a) selected from the group consisting of [tetramethylenediamine, hexamethylendiamine, polyethylenediamine H 2 N--CH 2 --CH 2 (NH--CH 2 CH 2 ) b --NH 2 in which b=1-6,]1,2-, 1,3- and 1,4-diaminocyclopentane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis-(aminomethyl)-cyclohexane, 1,4-bis-(aminoethyl)-cyclohexane, 3,3'-, 3,4'- and 4,4'-diaminodicyclohexylmethane, [1,3-xylylenediamine, 1,4-xylylenediamine, N-ethylaminopiperazine,]3-amino-methyl-3,5,5-trimethylcyclohexylamine(isophoronediamine), [N,N-dimethyl-N'(3-aminopropyl)-1,3-diaminopropane]3(4), 8(9)-bisaminomethyltricyclo(5.2.10 2 .6)decane and mixtures thereof, and (d) a photopolymerization catalyst for compound (b); (ii) exposing said impregnated material to actinic radiation until said composition solidified to give a substantially solid layer as a result of the photopolymerization of acrylic ester (b), whereas the epoxide resin remains substantially in a heat-curable state; and (iii) heating said solidified composition to temperatures from 60° to 120° C. within a time interval from 10 to 120 minutes to effect curing of the epoxide resin; said epoxide resin (a) and photopolymerizable acrylic ester (b) being present in a weight ratio of 100:3 to 100:30 such that, after irradiation with actinic light, the composition can still be shaped by thermoplastic methods.