Process for the preparation of heterophasic propylene copolymer compositions (RAHECO) made from or containing a random propylene copolymer (RACO) and an elastomeric propylene copolymer (BIPO), the process being carried out in a reactor having two interconnected polymerization zones, a riser and a downcomer, wherein growing polymer particles: (a) flow through the first polymerization zone, the riser, under fast fluidization conditions in the presence of propylene and of ethylene or an alpha-olefin having from 4 to 10 carbon atoms, thereby obtaining the random propylene copolymer (RACO); (b) leave the riser and enter the second polymerization zone, the downcomer, through which the growing polymer particles flow downward in a densified form in the presence of propylene and of ethylene or an alpha-olefin having from 4 to 10 carbon atoms, wherein the concentration of ethylene or of the alpha-olefin in the downcomer is higher than in the riser, thereby obtaining the elastomeric propylene copolymer (BIPO); and (c) leave the downcomer and are reintroduced into the riser, thereby establishing a circulation of polymer between the riser and the downcomer.

Process for the preparation of heterophasic propylene copolymer compositions (RAHECO) made from or containing a random propylene copolymer (RACO) and an elastomeric propylene copolymer (BIPO), the process being carried out in a reactor having two interconnected polymerization zones, a riser and a downcomer, wherein growing polymer particles: (a) flow through the first polymerization zone, the riser, under fast fluidization conditions in the presence of propylene and of ethylene or an alpha-olefin having from 4 to 10 carbon atoms, thereby obtaining the random propylene copolymer (RACO); (b) leave the riser and enter the second polymerization zone, the downcomer, through which the growing polymer particles flow downward in a densified form in the presence of propylene and of ethylene or an alpha-olefin having from 4 to 10 carbon atoms, wherein the concentration of ethylene or of the alpha-olefin in the downcomer is higher than in the riser, thereby obtaining the elastomeric propylene copolymer (BIPO); and (c) leave the downcomer and are reintroduced into the riser, thereby establishing a circulation of polymer between the riser and the downcomer.

A combined sealing member is provided that includes a composition comprising two or more polyolefin elastomers selected from the group consisting of a dense, a micro-dense and a dynamic silane-crosslinked polyolefin elastomer having a respective density of less than 0.90 g/cm.sup.3, less than 0.70 g/cm.sup.3, and less than 0.60 g/cm.sup.3. The combined sealing member exhibits a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).

The present disclosure provides a composition. In an embodiment, the composition includes a non-irradiated ethylene/propylene/non-conjugated polyene terpolymer (nr-terpolymer) and a branched ethylene/propylene/non-conjugated polyene terpolymer (b-terpolymer). The b-terpolymer has: (A) a Mooney viscosity (ML 1+4 @ 125° C.) from 35 MU to 120 MU; (B) a rheology ratio from 55 to 110; and (C) a phase angle δ from 20° to 39°.

The present disclosure provides a composition. In an embodiment, the composition includes a non-irradiated ethylene/propylene/non-conjugated polyene terpolymer (nr-terpolymer) and a branched ethylene/propylene/non-conjugated polyene terpolymer (b-terpolymer). The b-terpolymer has: (A) a Mooney viscosity (ML 1+4 @ 125° C.) from 35 MU to 120 MU; (B) a rheology ratio from 55 to 110; and (C) a phase angle δ from 20° to 39°.

A tire with improved wear resistance, rolling resistance and cohesion, comprises a rubber composition based on at least one elastomeric matrix comprising predominantly a random copolymer comprising ethylene units and conjugated diene units, the mole fraction of ethylene units in the copolymer being within a range extending from 50% to 95%; a peroxide; and a specific polyfunctional acrylate; the contents of polyfunctional acrylate and of peroxide being such that the ratio of the peroxide content to the polyfunctional acrylate content is greater than or equal to 0.08; said composition comprising from 5 to less than 65 phr of reinforcing filler; the ratio of the filler content to the polyfunctional acrylate content being greater than or equal to 1.25.

A tire with improved wear resistance, rolling resistance and cohesion, comprises a rubber composition based on at least one elastomeric matrix comprising predominantly a random copolymer comprising ethylene units and conjugated diene units, the mole fraction of ethylene units in the copolymer being within a range extending from 50% to 95%; a peroxide; and a specific polyfunctional acrylate; the contents of polyfunctional acrylate and of peroxide being such that the ratio of the peroxide content to the polyfunctional acrylate content is greater than or equal to 0.08; said composition comprising from 5 to less than 65 phr of reinforcing filler; the ratio of the filler content to the polyfunctional acrylate content being greater than or equal to 1.25.

The invention relates to a process for the preparation of a final heterophasic propylene copolymer (A) having a final melt flow rate in the range from 65 to 110 dg/min, comprising visbreaking an intermediate heterophasic propylene copolymer (A′) having an intermediate melt flow rate, which intermediate melt flow rate is lower than the final melt flow rate, to obtain the final heterophasic propylene copolymer, wherein the intermediate heterophasic propylene copolymer (A′) consists of (a) a propylene-based matrix, (b) a dispersed ethylene-α-olefin copolymer,
wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene-α-olefin copolymer in the intermediate heterophasic propylene copolymer is 100 wt % based on the intermediate heterophasic propylene copolymer.

The invention relates to a process for the preparation of a final heterophasic propylene copolymer (A) having a final melt flow rate in the range from 65 to 110 dg/min, comprising visbreaking an intermediate heterophasic propylene copolymer (A′) having an intermediate melt flow rate, which intermediate melt flow rate is lower than the final melt flow rate, to obtain the final heterophasic propylene copolymer, wherein the intermediate heterophasic propylene copolymer (A′) consists of (a) a propylene-based matrix, (b) a dispersed ethylene-α-olefin copolymer,
wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene-α-olefin copolymer in the intermediate heterophasic propylene copolymer is 100 wt % based on the intermediate heterophasic propylene copolymer.

The present invention provides a 4-methyl-1-pentene/α-olefin copolymer being excellent in lightness, stress absorption, stress relaxation, vibration damping properties, scratch resistance, abrasion resistance, toughness, mechanical properties and flexibility, having no stickiness during molding operation and being excellent in the balance among these properties; a composition comprising the polymer; and uses thereof. The 4-methyl-1-pentene/α-olefin copolymer (A) of the present invention satisfies specific requirements, and comprises 5 to 95 mol % of a structural unit (i) derived from 4-methyl-1-pentene, 5 to 95 mol % of a structural unit (ii) derived from at least one kind of α-olefin selected from α-olefins having 2 to 20 carbon atoms excluding 4-methyl-1-pentene and 0 to 10 mol % of a structural unit (iii) derived from a non-conjugated polyene, provided that the total of the structural units (i), (ii), and (iii) is 100 mol %.