RU2000112413A - METHOD FOR PRODUCING HETEROPHASIC POLYMER COMPOSITIONS AND COMPOSITIONS OBTAINED IN SUCH METHOD - Google Patents

Claims (8)

1. A method of obtaining a heterophasic polyolefin composition, comprising i) a stage during which the polymerization of propylene is carried out in any order to form a crystalline propylene polymer of at least 80 wt. % of which is insoluble in xylene at ambient temperature, or polymerization of propylene with ethylene and / or C ₄ -C ₁₀ α-olefin to form a crystalline propylene copolymer containing more than 85 wt. % propylene, or polymerization of ethylene to form an ethylene homopolymer, or ethylene with a C ₃ -C ₁₂ α-olefin to form an ethylene copolymer containing up to 20 mol. % C ₃ -C ₁₂ α-olefin, and b) copolymerization of ethylene with a C ₃ -C ₁₀ α-olefin, and optionally a diene, with the formation of an elastomeric copolymer partially soluble in xylene at ambient temperature containing up to 70 wt. % ethylene in a fraction soluble in xylene at ambient temperature; wherein said step is carried out in the presence of a Ziegler-Natta catalyst (1), obtained by contacting the following components of a catalytic component comprising a titanium compound and an electron donor compound, both of which are supported on magnesium chloride; an organometallic compound and, optionally, an electron donor compound ii) a processing step during which the polymer obtained in the polymerization step (i) is contacted in any sequence a) with a compound capable of deactivating the catalyst present in step (i), b ) with a catalyst (2) obtained by contacting (I) a compound containing a transition metal M and at least one ligand forming a π-bond with metal M, and (II) at least one cocatalyst selected , on the for example, from aluminoxanes iii) a copolymerization step during which ethylene and a C ₃ -C ₁₀ α-olefin are polymerized in the presence of a polymer treated in the manner of step (ii) and said catalyst (2).  2. The method according to p. 1, in which at the stage of copolymerization (iii) the molar ratio between ethylene and the total amount of supplied monomers varies from 0.5 to 0.7.  3. The method according to p. 1 and 2, in which the fraction of the elastomeric copolymer (1) (b), soluble in xylene, contains up to 40 wt. % ethylene. 4. The method according to p. 1-3, in which the C ₃ -C ₁₀ α-olefin is propylene or 1-butene.  5. Polymer compositions obtained using the method according to PP. 1-4. 6. The polymer composition according to p. 5, containing, by weight. %: 1) 10-45%, preferably 15-40%, of a fraction of a crystalline polymer selected from the following compounds: a propylene homopolymer whose solubility in xylene at ambient temperature is more than 80%, preferably more than 90%, a copolymer of propylene with ethylene or C ₄ -C ₁₀ α-olefin, or a mixture of these comonomers; moreover, these copolymers contain more than 85% propylene and are insoluble in xylene at an ambient temperature of more than 80%; or a homopolymer or copolymer of ethylene with a C ₃ -C ₁₂ α-olefin, wherein said copolymer contains up to 20 mol. % C ₃ -C ₁₂ α-olefin, 2) from 16 to 55%, preferably from 16 to 50% of a fraction partially soluble in xylene at ambient temperature consisting of copolymers of ethylene with a C ₃ -C ₁₀ α-olefin; wherein said fraction contains an elastomeric copolymer of ethylene with a C ₃ -C ₁₀ α-olefin and optionally minor amounts of diene soluble in xylene at ambient temperature, and from 1 to 15% of the sum of said fractions (1) and (2) crystalline a copolymer of ethylene with a C ₃ -C ₁₀ α-olefin, insoluble in xylene at ambient temperature; wherein said elastomeric copolymer contains up to 40% ethylene, 3) 15-60, preferably 20-60%, of an elastomeric copolymer selected from copolymers of ethylene with a C ₃ -C ₁₀ α-olefin, with a molar content of ethylene from 30 to 75%; wherein said copolymer is related

lower than 4, said polymer compositions having a ratio of the amount of said fraction soluble in xylene at ambient temperature in the copolymer fraction (2) and the amount of polymer fraction (1) equal to or lower than 1.5.  7. Compositions according to claim 6, in which the elastomeric copolymer (3) has an intrinsic viscosity of more than 1.5 dl / g.  8. Products obtained from compositions according to paragraphs. 6 and 7.