FIELD: chemistry.
SUBSTANCE: invention relates to various versions of prepregs, methods for production thereof and methods of making a composite article based on said prepregs. Prepreg contains a layer of impregnated reinforcing fibres and contains at least one layer of reinforcing fibres impregnated with a resin composition which contains at least a thermosetting resin, a curing agent and an accelerator. Accelerator has a gradient concentration which is more concentrated in the resin composition near the reinforcing fibres than in the distance. Resin composition contains a first resin composition impregnating reinforcing fibres, providing a layer of impregnated reinforcing fibres, and a surface layer. Surface layer contains second resin composition and is formed on layer of impregnated reinforcing fibres. First resin composition has at least one peak on the exothermic curve, which occurs each time before and / or at a temperature lower than any peak on the exothermic curve of the second resin composition. Heat release of the first resin composition is designed to initiate or accelerate the reaction of the second resin composition, leading to a significant reduction in the period of the curing cycle of the prepreg. Second resin composition contains at least thermosetting resin and hardener. Thermosetting resin of the second resin composition is the same or different from that of the first resin composition. Prepreg includes an interlayer impact strength reinforcement. Prepreg is impregnated with a plurality of reinforcing fibres on one side or both of the first and second resin compositions.
EFFECT: invention provides excellent capability of transportation and processing of uncured prepreg, as well as excellent thermal and mechanical properties in hardened state.
15 cl, 3 tbl, 10 ex, 1 dwg
