| abstract |
Polymer of ethylene having a swelling rate (T G ) of at least 1.4, a resistance to stress cracking (ESCR) of at least 55 h and a melt index of MI 5 of at least 0.2 g / 10 min. Processes for obtaining this ethylene polymer using different catalytic systems, the first based on titanium and zirconium used in a polymerization in two reactors; the second consisting of a mixture of a titanium catalyst and a titanium and zirconium catalyst, used in a polymerization in two reactors; the third based on chromium on a support comprising at least two constituents chosen from silica, alumina and aluminum phosphate, used in a polymerization in a single or in two reactors. |