| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat insulating material for a hot water storage tank for a heat pump water heater, which has such a level of heat resistance that a dimensional change rate in heating at 90°C for 168 h is within ±0.5%, ensures excellent property of filling into a cavity in molding, is compact, and has flame retardancy not spoiling thermal insulation property.SOLUTION: As for expandable polystyrenic resin particles for a heat insulating material used for a hot water storage tank of a heat pump water heater, polystyrenic resin particles having a coefficient of variation (CV) in particle diameter of 5-15% are dispersed in an aqueous suspension, and before or during impregnating a blowing agent, a flame retardant solution prepared by dissolving 40-300 pts.wt. of a 2,2-bis[4-(2,3-dibromoalkoxy)-3,5-dibromophenyl]-propane as a bromine-based flame retardant in 100 pts.wt. of a plasticizer is fed into the aqueous suspension and the flame retardant is impregnated into the polystyrenic resin particles. |
