Abstract: A process for preparing a polyethylene composition made from or containing bimodal or multimodal polyethylene in an extruder device including the steps of (i) mixing a bimodal or multimodal polyethylene having a density from 0.940 g/cm3 to 0.968 g/cm3, in the form of a polyethylene powder, with an additive, in a mixing device at a temperature from 10° C. to 100° C. without melting the polyethylene powder; (ii) melting and homogenizing the mixture within the extruder device, thereby forming a molten polyethylene composition; and (iii) pelletizing the molten polyethylene composition, and further (iv) adding a liquid made from or containing an organic peroxide, in an amount from 20 ppm to 200 ppm of organic peroxide with respect to the polyethylene powder, to the polyethylene powder at a position where mixing occurs and the polyethylene powder has a temperature of from 10° C. to 100° C.

Abstract: A continuous process for preparing a multimodal polyolefin composition made from or containing one or more antioxidants, including the steps of: preparing a multimodal polyolefin in form of a polyolefin powder, having a mass-median-diameter D50 in the range from 300 ?m to 2500 ?m, in a series of polymerization reactors; mixing the polyolefin powder and an organic peroxide without melting the polyolefin powder; melting and homogenizing the mixture within an extruder device; adding one or more antioxidants to the molten polyolefin composition; homogenizing the combination of molten polyolefin composition and antioxidant, thereby forming an antioxidant equipped molten polyolefin composition; and pelletizing the antioxidant equipped molten polyolefin composition.

Abstract: A process for preparing a polyethylene composition made from or containing bimodal or multimodal polyethylene in an extruder device including the steps of (i) mixing a bimodal or multimodal polyethylene having a density from 0.940 g/cm3 to 0.968 g/cm3, in the form of a polyethylene powder, with an additive, in a mixing device at a temperature from 10° C. to 100° C. without melting the polyethylene powder; (ii) melting and homogenizing the mixture within the extruder device, thereby forming a molten polyethylene composition; and (iii) pelletizing the molten polyethylene composition, and further (iv) adding a liquid made from or containing an organic peroxide, in an amount from 20 ppm to 200 ppm of organic peroxide with respect to the polyethylene powder, to the polyethylene powder at a position where mixing occurs and the polyethylene powder has a temperature of from 10° C. to 100° C.

Abstract: A process for preparing a polyolefin composition including the steps of supplying a bimodal or multimodal polyolefin in form of a polyolefin powder having an mass-median-diameter D50 in the range from 300 ?m to 2500 ?m and one or more additives to a mixing device, mixing the polyolefin powder and the additives at a temperature from 10° C. to 120° C., transferring the mixture into a extruder device, melting and homogenizing the mixture within the extruder device to form a molten polyolefin composition, and pelletizing the molten polyolefin composition.

Abstract: A process for homogenizing and pelletizing a polyethylene composition comprising the steps of a) providing a polyethylene composition having a density of from 0.90 g/cm3 to 0.97 g/cm3 and a melt flow rate MFR21.6 at 190° C. under a load of 21.6 kg of from 1 g/10 min to 80 g/10 min, b) melting the polyethylene composition; c) passing the melt through a combination of screens consisting of screens having a mesh opening of at least 205 ?m and comprising at least two screens having a mesh opening of from 205 ?m to 350 ?m; and e) pelletizing the molten polyethylene composition, the use of a polyethylene composition obtained by such a process for the preparation of films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles and films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles prepared from a polyethylene composition obtained by such a process.

Abstract: A process for the anti-sticking treatment of polymer pellets comprising: a) pelletizing the polymer in the presence of cooling water; b) drying the polymer pellets by means of a centrifugal drier, wherein in step b) an aqueous composition comprising an anti-sticking agents is metered inside said centrifugal drier.

Abstract: A process for homogenizing and pelletizing a polyethylene composition comprising the steps of a) providing a polyethylene composition having a density of from 0.90 g/cm3 to 0.97 g/cm3 and a melt flow rate MFR21.6 at 190° C. under a load of 21.6 kg of from 1 g/10 min to 80 g/10 min, b) melting the polyethylene composition; c) passing the melt through a combination of screens consisting of screens having a mesh opening of at least 205 ?m and comprising at least two screens having a mesh opening of from 205 ?m to 350 ?m; and e) pelletizing the molten polyethylene composition, the use of a polyethylene composition obtained by such a process for the preparation of films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles and films, fibers, pipes, blow-molded articles, injection-molded articles, compression-molded articles or rotomolded articles prepared from a polyethylene composition obtained by such a process.

Abstract: A process for the anti-sticking treatment of polymer pellets comprising: a) pelletizing the polymer in the presence of cooling water; b) drying the polymer pellets by means of a centrifugal drier, wherein in step b) an aqueous composition comprising an anti-sticking agents is metered inside said centrifugal drier.

Abstract: Compositions of additives for plastics comprising the following components (percent by weight): A) from 1% to 25% of a polyolefin matrix comprising one or more polyolefins having a melting point of 160° C. or less, said melting point being determined by differential scanning calorimetry (DSC), according to ISO 11357; B) from 75% to 99% of one or more solid additives for polymers.

Abstract: Polyolefin compositions comprising one or more crystalline polymers or copolymers of 1-olefins having Melt Index values higher that 20 g/10 min, and, dispersed in the above mentioned polymers or copolymers, a cellulosic material in the form of particles or fiber, as well as the process for the preparation of the above mentioned compositions in pelletized form and their conversion into products by way of injection molding.

Abstract: Polyolefin compositions having good transparency and impact resistance even at low temperatures including (by weight):A) from 25 to 95 parts of a crystalline random copolymer of propylene with ethylene and/or another .alpha.-olefin, containing more than 85% by weight of propylene, and having Haze values lower than 25%; andB) from 5 to 75 parts of a component comprising (a) an elastomeric copolymer of ethylene with propylene and/or another .alpha.-olefin, and optionally with minor proportions of a diene, containing 20-80 parts of ethylene, and (b) one or more of the polymers selected from LLDPE, LDPE, HDPE, having a Melt Index higher than 0.5 g/10 min., said (a) and (b) being present in such proportions that the ratio between the density of (A) and calculated average density of (B) is from 0.980 to 1.015.