| 摘要 |
Provided are biodegradable fibers of polylactic acid having a number-average molecular weight of from 50,000 to 150,000, which are so designed that the alkali solubility of the inside part of each fiber is larger than that of the outer peripheral part thereof and the surface of each fiber has from 5 to 50 cracks/10 cm. The physical properties of the fibers are good and enough for practical use, and the biodegradation thereof is well controllable in any desired manner. |
