HIGHLY ELASTIC POLYOLEFIN COMPOSITION Russian patent published in 2010 - IPC C08L23/10 C08F2/00 

FIELD: chemistry.

SUBSTANCE: description is given of an olefin polymer composition used in pressure moulding and in hot moulding equipment, containing the following (in terms of weight): A) 60-85% crystalline propylene homopolymer characterised by polydispersity index (P.I) value ranging from 4.5 to 6 and content of isotactic pentades (mmmm) of over 96%, measured from ¹³C NMR in a fraction which is insoluble in xylene at 25°C; B) 15-40% partially amorphous ethylene copolymer containing from 35% to 70% propylene; the said olefin polymer composition has breaking stretching, in accordance with ISO 527, ranging from 150% to 600%. Also described is a method of preparing an olefin polymer composition through polymerisation in paragraph 1, involving at least two successive steps on which components (A) and (B) are obtained at different successive steps, carrying out each step, except the first, in the presence of the obtained polymer and the catalyst used at the previous step, and in the presence a Ziegler-Natta polymerisation catalyst containing a solid catalyst component which contains: a) Mg, Ti and a halogen and at least two electron donor compounds, said catalyst component is characterised by that, at least one of the electron donor compounds, present in amount ranging from 15 to 50 mol % of the total amount of donors, is selected from a class of succinates which are not extractable above 20 mol % and at least another electron donor compound which is extracted above 30 mol %; b) alkyl aluminium and optionally, c) one or more electron donor compounds.

EFFECT: highly elastic olefin polymer composition with high breaking elongation value is obtained.

5 cl, 3 tbl, 3 ex