| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an enough strength and to produce biodegradability in soil, etc., after use by a method wherein a material prepd. by mixing a polylactic acid polymer and an aliph. polyester except the polylactic acid by a specific ratio is extrusion-molded and is drawn and then, is heat-set. SOLUTION: Mixig of a polylactic acid polymer and an aliph. polyester is in a range of (95:5)-(30:70) by wt. ratio. Then, drawing treatment after extrusion molding is performed by heating an undrawn band in such a way that a drawing tank, i.e., a wet drawing tank such as a hot water tank and a dry heat drawing tank, using a far infrared rays heater, an electric heater, etc., as a heat source is arranged between rollers with different speeds or by heat transmission of a heat roll of feeding side, and the draw ratio is approximately 4-10 times. In addition, heat setting treatment after the drawing treatment orients the polylactic acid polymer and relaxes and disperses orientation of the aliph. polyester except the polylactic acid to attempt to make matrix tensile strength compatible with slitting resistance.</p> |
