| 摘要 |
<p>PURPOSE:To obtain a freshness-keeping agent capable of keeping ethylene- adsorption and removing function even in the presence of water at high concentration, by using a high-silica zeolite having pore inlet composed of a 12-membered ring and having a specific effective pore diameter as an active component. CONSTITUTION:The objective freshness-keeping agent contains a high-silica zeolite having an SiO2/Al2O3 molar ratio of about >=25, having pore inlet composed of a 12-membered oxygen ring and having an effective pore diameter of about 5-10Angstrom as an active component. The zeolites having the above pore inlet construction and effective pore diameter are mordenite-type, offretite-type or erionite-type, etc. Among the above zeolites, only those having an SiO2/Al2O3 molar ratio of about >=25 can be used as the present freshness-keeping agent. Since zeolite satisfying the above molar ratio condition is generally not found in nature, it must be chemically synthesized under a reaction condition to attain the objective SiO2/Al2O3 molar ratio or dealuminizing a natural zeolite or a synthetic zeolite having an SiO2/Al2O3 molar ratio of about 2-15 to increase the molar ratio to about >=25.</p> |
