| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a cooling agent having high safety and a higher cooling effect by incorporating water-repellent silica into sodium sulfate decahydrate and imparting temperature stability to the latter. SOLUTION: This cooling agent consists of a mixture of an ammonium salt with urea and a mixture of sodium sulfate decahydrate with water-repellent silica, wherein the water-repellent silica is blended in an amount of 0.01-2.0 pts.wt. based on 100 pts.wt. sodium sulfate decahydrate. The ammonium salt used preferably comprises ammonium nitrate. The urea and sodium sulfate decahydrate used may be articles generally on the market for industrial uses. The water-repellent silica used may be one usually on the market. For example, a mixture of 50g of sodium sulfate decahydrate with 0.1g of water-repellent silica is enclosed in a small bag, which is put in an outer bag containing 30g of ammonium nitrate and 30g of urea and is hermetically sealed. After being left to stand at 40 deg.C for 24hr and then at 0 deg.C for 24hr, it is used in an atmosphere at 36 deg.C as a cooling agent by breaking the inner small bag (the temperature becomes -7.3 deg.C).</p> |
