PURPOSE: To provide a quality laminated composite by reacting a reaction mixture of plastic additives with an organic di- or polyisocyanate, predetermined quantity of cyclic alkylene carbonate, third class amine, and cyclic alkylene carbonate.

CONSTITUTION: A laminated composite is manufactured by a method wherein at least a layer of rigid polyisocyanurate thermosetting composite made by reacting in a mold at about 140°C a reaction mixture of soluble additives with an organic di- or polyisocyanurate and about 2-50 parts by weight (based on an isocyanate-carbonate mixture) of a cyclic alkylene carbonate and further, with about 0.005-3.0% by weight (based on the entire composition) density of the third class amine and a cyclic alkylene carbonate, and at least a layer out of the material series selected from metal, cellulose, plastics, glass and ceramics is injected in a compressed mold or formed by combining such layers in an RIM machine.