| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide such a method for manufacturing a polyvinyl alcohol aqueous solution by dissolving a polyvinyl alcohol in water at a temperature close to 100°C, which can give an aqueous solution excellent in the clarity and homogeneity without causing reprecipitation or gelation under a condition cooled down to the vicinity of a room temperature, even when the polyvinyl alcohol has a high degree of polymerization or a high degree of saponification and even when the polyvinyl alcohol has a high concentration. Ž<P>SOLUTION: The method for manufacturing a polyvinyl alcohol aqueous solution, comprising a dissolution process of dissolving a polyvinyl alcohol in water by mixing the polyvinyl alcohol with water at a temperature of 80°C or higher and a cooling process of cooling the polyvinyl alcohol aqueous solution, which is obtained and kept at a given temperature of 80°C or higher, down to a given temperature ranging from 10 to 40°C, is characterized in that the cooling process is carried out so that the cooling rate defined as the following formula (1) may be 1°C/minute or higher; formula (1): cooling rate=(solution temperature at the time of the cooling start-solution temperature at the time of the cooling finish)/cooling time. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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