Patent ID: 7141639

Claim:
A copolymer of ethylene and α-olefin of from 4 to 20 carbon atoms having a melt flow rate (MFR) measured at 190° C. under a load of 21.18 N according to JIS K7210-1995 of from 1.4 to 10 g/10 minutes, a melt tension (MT) at 190° C., an intrinsic viscosity ([η]) and a chain length A satisfying following formulas (1) to (3), a melt flow rate ratio (MFRR) of 60 or more that is calculated by dividing the melt flow rate measured at 190° C. under a load of 211.82 N according to JIS K7210-1995 by said MFR measured at 190° C. under a load of 21.18 N, and an activation energy for melt flow of 54 kJ/mol or more, wherein the length A is a chain length at peak position of a logarithm normal distribution curve of a component having the highest molecular weight among logarithm normal distribution curves obtained by dividing a chain length distribution curve obtained by gel permeation chromatography measurement into at least two logarithm normal distribution curves, 2× MFR −0.59 <MT <20× MFR −0.59 formula (1) 1.02 ×MFR −0.094 <[η]<1.50 ×MFR 0.156 formula (2), and 3.30<log A <−0.0815×log( MFR )+4.05 formula (3).