| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an extruded polystyrene resin foam board which is produced by using a hydrocarbon-based foaming agent, that has zero ozone depletion potential and a small global warming potential and is of the amount larger than before, and which has excellent flame retardancy and low thermal conductivity over a long period of time. <P>SOLUTION: The extruded polystyrene resin foam board is obtained by extrusion foaming of a foamable and meltable resin mixture comprising a flame retardant, a polystyrene resin, and a mixed physical blowing agent, which comprises physical blowing agents to be selected from a specific (a) group, physical blowing agents to be selected from a specific (b) group and, if necessary, physical blowing agents to be selected from a specific (c) group. The extruded polystyrene resin foam board has ≥10 mm thickness and 25-60 kg/m<SP POS="POST">3</SP>apparent density. The total residual amount of the physical blowing agents to be selected from the specific (a) group in the extruded polystyrene resin foam board after one week has passed is >3.5 wt.% and that of the physical blowing agents to be selected from the specific (a) group in the extruded polystyrene resin foam board after four weeks have passed is 3.0-4.5 wt.%. The average bubble size of the extruded polystyrene resin foam board in the thickness direction is 0.05-0.02 mm and the bubble deformation ratio (the average bubble size thereof in the thickness direction/the average bubble size thereof in the horizontal direction) is 0.7-1.2. <P>COPYRIGHT: (C)2012,JPO&INPIT |
