The invention belongs to the field of
epoxy resin composite materials, and particularly provides a high-strength low-density
epoxy SMC
composite material and a preparation method thereof.The preparation method comprises the following steps that S01, a PVC core plate is taken, grooving is conducted, then glue brushing is conducted, then
fiber cloth is laid, film covering is conducted, negative pressure vacuumizing is conducted, then presoaking liquid is poured, and standing is conducted to obtain a precured
composite plate; and S02, taking the pre-cured composite board, carrying out mold pressing treatment, standing overnight, and carrying out demolding and trimming treatment, so as to obtain the composite board. The preparation method of the prepreg liquid comprises the following steps: mixing a
reactive diluent, an
accelerant, modified microspheres and a filler, adding
epoxy resin for the first time, stirring, supplementing the balance of epoxy resin, adding a curing agent and a
release agent, and continuously mixing to obtain the prepreg liquid; the SMC
composite material product prepared by using the modified microspheres as a preimpregnation liquid adding component has the density of less than or equal to 1.57 g / cm < 3 >, the
impact strength of more than or equal to 84.5 KJ / m < 2 > and good
flame retardance.