| 摘要 |
PURPOSE:To obtain a propylene polymer for a container lid which is excellent in extrusion stability, cuttability of the melt, fidelity to a metal mold, etc., by maintaining the MFR, the die swell, and the isotactic pented fraction each in a specified range. CONSTITUTION:This polymer which has an MFR [measured according to JIS K 7210 (at 230 deg.C under 2.16kg load)] of 0.5-10g/10min, a die swell [measured by using the ratio of the diameter of a die to that of a discharged resin melt at a diameter of the die of 1mm at a resin temp. of 190 deg.C under a shear rate of 24.3sec<-1> using Capirograph] of 0.9-1.4, and an isotactic pented fraction [isotactc fraction in pented units in polypropylene molecular chains measured by <13>C-NMR (nuclear magnetic resonance)] of 0.96 or higher. The polymer is excellent in production stability, esp. in high-speed molding, on a container-lid molding machine comprising an extruder and a compression molding machine. |
