| 摘要 |
PURPOSE:To obtain an ethylene copolymer having a narrow compositional distribution and improved melt tension, fluidity, heat stability, transparency and mechanical strengths by specifying its density, melt flow rate and flow index. CONSTITUTION:65-99wt.% ethylene is copolymerized with 35-1wt.% 3-20C alpha-olefin in the presence of an olefin polymerization catalyst to obtain a copolymer having a density (d) of 0.880-0.950g/cm<3> and a melt flow rate(MFR) (under a load of 2.16kg at 190 deg.C) of 0.01-200g/10min and satisfying the relationship: Tm<400d-250 (wherein Tm ( deg.C) is the temperature at the highest peak in the endotherm as measured with a differential scanning calorimeter), relationship I (wherein W is the rate of the decane-solubles at room temperature) for MFR <10g/min, relationship II for MFR>10g/min, FI>75XMFR (wherein FI (1/sec) is the flow index which is a shear rate shown when the shear stress of a polymer melt at 190 deg.C is 2.4X10<6>dyn/cm<2>, and MT>2XMFR<-0.65> (wherein MT is the melt tension at 190 deg.C). |
