| abstract |
A honeycomb core material for a sandwich structure which comprises a honeycomb body having a cell size of 3 to 100 mm and a porosity of 92 to 99.5 % according to JIS-A6931 and, filled in cells thereof, a composite foam comprising a phosphate-containing inorganic foam prepared by expanding an aqueous mixture containing a phosphate, a curing agent, a blowing agent and an urethane polymer having NCO groups, followed by curing, and an urethane type organic foam. The honeycomb core material is excellent in flame retardation, thermal insulation and noise insulation and has improved transportability and handleability, and further can be suitably used also for a sandwich structure having a curved face due to the softness and flexibility of the foam. |