| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a polyethylene for pipes and joints, which has excellent durability, short crystallization time, and high flowability/melt tension, is capable of being molded in a high cycle in both of an injection molding method and an extrusion molding method, and is excellent in dimensional stability, scratch resistance and the like, and to provide a molding of the polyethylene.SOLUTION: The polyethylene for pipes and joints satisfies the following characteristics (i)-(vi). The characteristic (i) is that HLMFR thereof (measured at the temperature of 190°C and under a load of 21.6 kg) is 8-30 g/10 minutes. The characteristic (ii) is that the density thereof is 0.947-0.960 g/cm. The characteristic (iii) is that the rupture time thereof at a full notch creep test (measured at 80°C and under 5 MPa) is 300 hours or longer. The characteristic (iv) is that the peak top time thereof, when the polyethylene is crystallized isothermally at 121.5°C, is 300 seconds or shorter when the peak top time is measured by DSC. The characteristic (v) is that the flexural modulus thereof (at 23°C) is 950 MPa or higher. The characteristic (vi) is that the melt tension thereof at 190°C is 100 mN or higher.</p> |
