| 摘要 |
PURPOSE:To obtain a cooling medium causing no syneresis even when thawed after freezing and having a large capacity for cooling by impregnating a specified gel consisting of an aqueous PVA solution and a water-containing, highly water-absorptive resin with a specified quantity of water to provide a hydrogel in a packaging bag make of a water-impermeable film. CONSTITUTION:Preferably a mixed paste obtained by adding water to a mixture of a PVA and a highly water-absorptive resin (e.g. a crosslinked sodium polyacrylate) is caused to gel with a chemical or by freezing, thereby giving a gel consisting of an aqueous PVA solution and a water-containing, highly water-absorptive resin at a weight ratio of the resin solid of the former to that of the latter of (20:80) to (80:20) and having a resin solid content of 4-10wt.% The gel thus obtained and water are put in a packaging bag preferably made of a water-impermeable film (e.g. PE film) so as to impregnate 100 pts.wt. of the gel with 50-500 pts.wt. water to form a hydrogel in the packaging bag, thus giving the title cooling medium. |
