OPEN-CELL FOAMED MATERIAL, CORE MATERIAL FOR VACUUM HEAT INSULATING MATERIAL AND VACUUM HEAT INSULATING MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide an open-cell foamed material having a high expansion ratio, excellent light weight, heat insulation, air permeability, moisture permeability and the like, an open-cell foamed material further having excellent heat insulation, a core material for a vacuum heat insulating material made of the foamed material and the vacuum heat insulating material in a polystyrene resin foamed material having excellent recyclability and easy handleability. SOLUTION: An extrusion foamed material is made of a polystyrene resin foamed material, The extrusion foamed material has an open-cell expansion ratio of 90% or more, a density of 0.03 to 0.4 g/cm3, a foam size in a thickness direction of less than 400 m, a ratio of a foam size in a thickness direction to a foam size in a width direction and a ratio of a foam size in a thickness direction to a foam size in a length direction all of 0.1 to 1.2. The open-cell foamed material is exposed at a section of the foam on a surface of the material.