| 摘要 |
PROBLEM TO BE SOLVED: To provide vacuum heat insulating material having excellent heat insulation property over a long period of time.SOLUTION: This vacuum heat insulating material 1 includes a permeable core 2, and outer cover materials 4 having gas barrier layers 6 and thermally welded layers 7. The core 2 is depressurized and sealed between the two outer cover materials 4 with the thermally welded layers 7 opposed, and the peripheries of the two outer cover materials 4 are thermally welded to each other. Some of the thermally welded layers 7 in thermally welded sealing portions 9 are formed with thin-walled portions 10 with the thermally welded layers 7 relatively thinned. The thin-walled portions 10 are formed in deepest positions of arcuate opposed recessed portions provided to boundary surfaces between the thermally welded layers 7 and gas barrier layers 6 in the sealing portions 9. The thermally welded layers 7 are layered on the gas barrier layers 6 by extruding. Therefore, there is no adhesive layer between the gas barrier layers 6 and thermally welded layers 7, and temporal intrusion of atmospheric gas into the vacuum heat insulating material 1 is suppressed. |
