| abstract |
Ethylene copolymers derived from ethylene and C3-C20 olefins, which do not contain quaternary carbon in the main chain and have an activation energy (Ea) of melt flow of 8-20 kcal/mol, and wherein (1) the Huggins constant (k1) of the copolymer and the Huggins constant (k2) of a linear ethylene polymer, both having the same limiting viscosities, satisfy the relationship of the formula: 1.12 < k1/k2 « 5, or (2) the molar ratio of the methyl groups to the methylene groups in the molecular chain, [CH3/CH2], is 0.005 to 0.1 and satisfies the relationship of the formula: Tm » 131 - 1340 [CH3/CH2], or (3) the Mw and the die swell ratio (DR) satisfy the relationship of the formula: DR > 0.5 + 0.125 x log Mw. These ethylene copolymers are different from ordinary HDPE, L-LDPE and LDPE, and are characterized in that they are excellent in processability and capable of the control of various properties, such as density, melting point and crystallinity. |