Thermosetting resin composition

A process for preparing a shaped article which comprising forming said shaped article from a thermosetting resin composition consisting essentially of, as resin components

• (A) 60 to 95% by weight of a prepolymer or precopolymer selected from the group consisting of (A-1), (A-2) and (A-3) below,
• (A-1) a prepolymer of diallyl phthalate,
• (A-2) a precopolymer of diallyl terephthalate derived from diallyl terephthalate of the following formula (1) ##STR24## and an aromatic benzyl hydrocarbon having at least one hydrogen atom at the benzyl position and represented by the following formula (2) ##STR25## wherein each of R.sup.1 and R.sup.2 represents a member selected from the class consisting of a hydrogen atom and lower alkyl groups, and n is an integer of 1 to 3, and
• (A-3) a mixture of (A-1) and (A-2), and
• (B) 40 to 5% by weight of a polyacrylate or polymethacrylate of dipentaerythritol having at least 4 acryloyl or methacryloyl groups in the molecule and represented by the following formula ##STR26## wherein each R.sup.3 represents a hydrogen atom, --COCH.dbd.CH.sub.2 or ##STR27## and at least four R.sup.3 groups represent --COCH.dbd.CH.sub.2 or ##STR28## and (C) about 1 to about 10 parts by weight of an organic peroxide as a curing agent per 100 parts by weight of the prepolymer or precopolymer (A);
• curing said thermosetting composition.