| 摘要 |
PURPOSE:To obtain an insulating material having a specific density of 60-200kg/ m<3> and a plate thickness of 2.5-7mm. by using a styrene-based copolymer resin which contains at least one component selected from specified acids and has a styrene content of 75-95wt% and a Vicat solftening point of not lower than 115 deg.C. CONSTITUTION:An ordinary organic foaming agent is mixed into a styrene-based copolymer resin containing at least one component selected from the group consisting of acrylic acid, methacrylic acid and maleic anhydride. The resin is extruded from an extrusion die 5 into the atmosphere at ordinary temperature and ordinary pressure, followed by inflation to simulaneously foam a parison and cool the outside surface thereof remakably. In the foamed plate 9 obtained through pinch rolls 8 the thickness T of a skin part and the thickness t of a cell film in a central part of the plate are in the relationship of :T/t>=2.5, and the flexure coefficient (p/y) according to JIS A-9511 is in the range of 1.5>=(p/y)>=0.2, where the definiton and determination conditions of the flexure coefficient (p/y) are as Formula. |
