| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a manufacturing method of a vacuum heat insulating material which is free from harmful deformation such as a warp, a bend, a projection, and a depression and causes no projection or depression deteriorating a commercial value on an outside wall face of an outer case of a heat insulated box body such as a cryogenic freezer, a refrigerator, and a freezer. SOLUTION: After heat treatment and deaeration of a core material 6 made of open cellular foamed polyurethane/polystyrene, the core material 6 is covered with a barrier bag with an adsorbent, and the inside of the barrier bag is evacuated to a vacuum condition of 9.3 Pa or less so as to be sealed. Then, the covered body covered with the barrier bag is put between two heat insulating sheets into a sandwich lamination so as to be adiabatically cooled down to an ordinary temperature with approximately uniform pressure applied to the whole surface by application of a load to the upper heat insulating sheet. In this way, a vacuum heat insulating material 4 is manufactured.</p> |
