US Patent 10112352 Press moulding method

A method of press molding a molding material to form a molded part of fiber-reinforced resin matrix composite material, the method comprising the steps of:i. locating a molding material in a mold tool, the molding material containing fibers, resin and a syntactic layer comprising a polymer matrix and a plurality of hollow bodies distributed within the polymer matrix;ii. permitting the molding material to drape at least partly under the action of gravity within the mold so as to configure at least part of the draped molding material in a partly molded shape;iii. fully closing the mold tool to define a closed mold cavity containing the molding material;iv. applying pressure to the mold cavity to cause resin to flow and impregnate the fibers and to configure the molding material in a fully molded shape; andv. substantially fully curing the resin to form a molded part from the molding material.