Patent ID: 8465832

Claim:
A composite laminated article comprising: a first layer of a fibre-reinforced resin, a second layer of a closed cell foam of a thermoplastic material, wherein the thermoplastic material is composed of a blend of polystyrene and polyphenylene oxide (PS/PPO), and a third layer of a fibre-reinforced resin, the resin of the first and third layers respectively adhering a surface of the first and third layers to a respective surface of the second layer to form a sandwich construction of the first, second and third layers, wherein the closed cell foam comprises a plurality of expanded beads mutually welded together, each bead comprising a plurality of closed cells, wherein in each bead the closed cell foam has an average cell size of from 15 to 75 microns, at least 50% of the beads comprise first beads having a uniform cell size in which the maximum cell size is 100 microns and at most 50% of the beads comprise second beads having a non-uniform cell size in which the majority of cells have a maximum cell size of 100 microns and a minority of cells have a maximum cell size from more than 100 microns to up to 660 microns.