| 摘要 |
A solidification- and extrusion-molded article of polyglycolic acid that is formed of a resin material containing polyglycolic acid, said polyglycolic acid having a melt viscosity of 200-2,000 Pa·s when measured at a temperature of 270°C under a shearing speed of 120 sec-1, and has a thickness or diameter of more than 100 mm but not more than 500 mm; a downhole tool or a component thereof and a ball sealer for petroleum excavation that are formed by machining the solidification- and extrusion-molded article; a method for manufacturing the solidification- and extrusion-molded article of polyglycolic acid, said method comprising a step for, after solidification- and extrusion-molding the resin material containing polyglycolic acid, pressurizing the solidified and extruded matter, and drawing the same while applying back pressure thereto in the direction of a forming die to thereby suppress the expansion of the solidified and extruded matter in the thickness direction or radial direction; and a method for manufacturing a ball sealer for petroleum excavation, etc. |
