| 摘要 |
<p>Ethylene copolymers having a linear structure, that is a structure which is essentially devoid of lengthy branch chains, and having a density not greater than 0.9450 g/cm<3>, are described. They are crystalline copolymers of ethylene with at least one other alpha olefin, having a density of from 0.9150 to 0.9450 g/cm<3> and a content of comonomer of from 1 to 7 mol%. The copolymers are further characterized by a melting point of from 115 to 130 DEG C, and X-ray crystallinity of from 39 to 55%, depending upon the content of comonomer, and a Melt Flow Index (according to ASTM D-1238) of from 0.1 to 50 g/10 min. The copolymers are prepared by the use of particular Ziegler catalytic systems in which the transition metal component has been prepared by reaction of a metal vapour with a titanium compound and a halogen donor.</p> |
