| 摘要 |
PROBLEM TO BE SOLVED: To obtain a dry chitin or chitosan powder efficiently at a low cost by directly charging and griding hardly grindable chitin or chitosan in the state of contg. water into and with a grinder without drying the chitin or chitosan. SOLUTION: Water-contg. chitin or chitosan is ground with a grinder to give a dry chitin or chitosan powder. Drying is carried out simultaneously with the grinding with a grinder. A pneumatic jet mill is used as the grinder. Before the grinding, the water content is 20-80% and the average particle size, 300μm-1 cm; and the powder obtd. by grinding has a water content of 10% or lower and an average particle size of 300μm or lower. The degradation in physical properties due to grinding is usually such that the viscosity retention after the grinding with a pneumatic jet mill is about 15-35%; however, when the water content is 20-80%, the viscosity retention after the grinding with a pneumatic jet mill is 25-45%, thus exhibiting a decreased degradation in physical properties.
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