ИСТИНА

Process for the preparation of an ethylene copolymer comprising polymerizing ethylene and a C4-10 alpha-olefin comonomer in a high temperature solution process at a temperature above 100 ° C in the presence of a catalytic system comprising (i) a metallocene complex of formula (I) ** (See formula) ** where M is Zr X is chlorine or a methyl radical, L is a bridge of formula -SiR8 2-, where each R8 is independently a C1 hydrocarbyl -C20, tri (C1-C20 alkyl) silyl, C6-C20 aryl, C7-C20 arylalkyl or C7-C20 alkylaryl n is 0, 1 or 2 R1 and R1 'are the same or may be different and may be an alkyl group C1-C6 linear or branched, R2 and R2 'are the same or different and are a group CH2-R9, with R9 being H or C1-C6 linear or branched alkyl group R5 and R6 taken together form a ring of 4-7 unsubstituted members fused to the benzene ring of the indenyl moiety; or R5 is an OR group, where R is a linear or branched C1-C6 alkyl group, and R6 is a C (R10) 3 group, with R10 being the same or different and R10 can be H or a C1- alkyl group C6 linear or branched; and R5 'and R6' taken together form an unsubstituted 4-7 membered ring fused with the benzene ring of the indenyl residue, provided that if R5 and R6 as well as R5 'and R6' taken together they form a ring of 5 unsubstituted members fused to the benzene ring of the indenyl moiety then R2 and R2 'are not a C1 alkyl group; and R7 and R7 'are the same or different and may be H or a linear or branched C1-C6 alkyl group (ii) an aluminoxane cocatalyst and (iii) a boron-containing cocatalyst.