Adsorbent, vacuum heat insulating material having the same and refrigerator

[0078]An oxygen-deficient titanium oxide 8.6 mg, a calcium oxide (made by Yoshizawa Lime Co., Ltd.) 4.0 mg and a palladium oxide (PdO: Wako Pure Chemical Industries, Ltd.) 0.1 mg were mixed, and the mixture was put in a porous nonwoven fabric (70 mm×70 mm, Yamanaka Kagaku Co., Ltd.), which was sealed in all directions to obtain the second adsorption component. After the vacuum heat insulating material (290 mm×410 mm×12 mm) is formed as described above, the thermal conductivity after one day at room temperature and the thermal conductivity after 14 days of acceleration test were evaluated. The difference between the thermal conductivity after one day and the thermal conductivity after the acceleration test was 0.27 mW / m·K. The content (mg / L) of the titanium oxide with respect to the volume of the pore space of the vacuum heat insulating material may be 6.70. The weight ratio (PdO / TiO2-x) of palladium oxide to oxygen-deficient titanium oxide may be 0.012.

[0079]The procedure of Example 1 was repeated except that oxygen-deficient titanium oxide 8.5 mg and palladium oxide 0.2 mg were used. The difference between the thermal conductivity after one day and the thermal conductivity after the acceleration test was 0.25 mW / m·K. The content (mg / L) of the titanium oxide with respect to the volume of the pore space of the vacuum heat insulating material may be 6.62. PdO / TiO2-x may be 0.024.

[0080]The procedure of Example 1 was repeated except that oxygen-deficient titanium oxide 7.0 mg and palladium oxide 1.7 mg were used. The difference between the thermal conductivity after one day and the thermal conductivity after the acceleration test was 0.24 mW / m·K. The content (mg / L) of the titanium oxide with respect to the volume of the pore space of the vacuum heat insulating material may be 5.45. PdO / TiO2-x may be 0.24.