Abstract: A honeycomb core material which is excellent in flame retardation, thermal insulation and noise insulation and has improved transportability and handling efficiency and which can be suitably used also for a sandwich structure of a curved shape as a foam has flexibility and elasticity, and a method for its production. A composite foam comprising a phosphoric acid type inorganic foam and a urethane type organic foam, obtained by foaming and curing an aqueous mixture containing a phosphorus-containing acid material, a curing agent, a blowing agent and a urethane polymer having NCO groups, is filled in cells of a honeycomb body having a cell size of from 3 to 100 mm and a porosity of from 92 to 99.5% according to JIS-A6931.

Abstract: A long fiber-reinforced thermoplastic resin molding material in the form of pellets each having inorganic filaments arranged substantially in the same length and in parallel in the same direction in a matrix of a thermoplastic resin, wherein the exposed ratio E as defined by the following formula (1) is at most 60%, on at least one end surface in the direction of the filaments of each pellet:E=(e/N).times.100 (1)where E is the exposed ratio (%), e is the number of inorganic filaments with their cross-sections exposed on at least one end surface in the direction of the filaments of each pellet, and N is the total number of inorganic filaments arranged in the pellet.