Patent ID: 7727448

Claim:
A method of making a thick part out of composite material comprising fiber reinforcement and a resin matrix, the method comprising the steps of: providing a fiber structure that is to form the reinforcement of the part to be made; placing the fiber structure in a mold having at least one wall that is formed by a flexible membrane; injecting into the mold a resin selected from phenolic and furanic resins, having a volatile material content of less than 25% by weight and at a temperature of a value such that its viscosity lies in the range 0.1 Pa·s to 0.3 Pa·s; and polymerizing the resin in the mold placed in an enclosure with temperature being raised progressively, the polymerization step including an initial stage of only partial polymerization during which the temperature is raised to a first value and suction is established in the mold in order to evacuate produced volatile materials, and a final stage of polymerization during which the pressure is raised in the enclosure and the temperature is raised progressively from the first value up to a final polymerization temperature to complete polymerization under pressure, whereby a composite material part is obtained presenting a residual porosity of less than 11% by volume.