VACUUM HEAT INSULATING MATERIAL, METHOD FOR MANUFACTURING SAME, HEAT RETAINING TANK USING SAME, AND HEAT PUMP WATER HEATER

摘要

This vacuum heat insulating material (1) is formed by providing a plurality of convex protrusions (5) on the surface of a core (3) on the inner side of a bend of the vacuum heat insulating material to be used while being bent, and putting the core on which the convex protrusions are provided in advance into a covering material (4) to vacuum-seal the core. Frictional force between the core and the covering member can be reduced by reducing the area of contact between the convex protrusions and the inner surface, which is in contact with the surface provided with the convex protrusions, of the covering member, and stress is uniformly dispersed without the core and the covering member getting locally entangled with each other even when the vacuum heat insulating material is bent, thereby making it possible to prevent large winkles from locally occurring on the inner side of the bend. Consequently, the vacuum heat insulating material having a high heat insulation property when used while being bent can be obtained.