| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a vacuum heat insulating material which secures an excellent heat insulating performance over a long period. <P>SOLUTION: A vacuum heat insulating material 1 is formed by sealing a core material 2 and an absorbent 3 between two rectangular outer covering materials 4 in a decompressed state in which thermal welding layers 7 are arranged opposite to each other, and by thermal welding together the outer peripheral parts on three sides near the peripheral edges of the two outer covering materials 4 covering the core material 2. The thermally fused layer 7 positioned in a sealing part 8 includes opposed recesses having a polygon having four sides or more when viewing a cross section when three sides of the sealing parts 8 where the outer peripheral parts of the covering member 4 are thermally fused are cut on a plane vertical to the peripheral edge, and a thin part 9 having a thickness of the thermally fused layer 7 thinner than the peripheral part of the innermost part is formed on the innermost part of the recess, and occurrence of a crack in the thin part 9 suppressing an atmospheric gas amount intruding from the end surface of the peripheral edge of the outer covering member 4 through the sealing part 8 and breakage of the sealing part 8 can be suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
