Composition obtained from recycled polyolefins

Abstract

A polyolefin composition comprising: (A) 60 to 95 wt% of a polyolefin component which is a mixture of a polypropylene-based component and a polyethylene-based component, and (B) 5 to 40% of a polypropylene composition, the polypropylene composition comprising (b1) 35 to 65% by weight of a polymer fraction comprising a propylene homopolymer or a copolymer containing at least 85% propylene, and (b2) 35 to 65% by weight of a polymer fraction comprising a copolymer of ethylene with propylene and / or a CH2=CHRα-olefin, the copolymer containing 25 to 40% by weight of ethylene. The polypropylene composition (B) allows for good compatibility between the polypropylene and polyethylene components present in (A).

Description

Technical Field

[0001] The present disclosure relates to a composition obtained from recycled polyolefins and a polypropylene-based composition as a compatibilizer. Background Art

[0002] Polyolefins, especially polyethylene and polypropylene, are increasingly being consumed in large quantities in many applications, including the packaging of food and other goods, fibers, automotive parts, and a wide variety of manufactured products. However, the said large-scale use of polyolefins has raised concerns about the environmental impact of the waste generated after the first use.

[0003] In fact, a large amount of waste plastic materials currently comes from the differential recycling of municipal plastic waste, mainly consisting of flexible packaging (cast film, blown film, and BOPP film), rigid packaging, blown bottles, and injection-molded containers. By a step of separating from other polymers such as PVC, PET, or PS, two main polyolefin fractions are obtained, namely polyethylene (especially HDPE, LDPE, LLDPE) and polypropylene (homopolymer, random copolymer, multiphase copolymer).

[0004] One of the key problems in polyolefin recycling, especially when dealing with material streams from post-consumer waste (PCW), is the difficulty in quantitatively separating polypropylene (PP) and polyethylene (PE). It has been found that commercial recyclates from PCW sources usually contain a mixture of PP and PE, with minor components reaching up to <50 wt%.

[0005] Such recycled PP / PE blends usually have deteriorated mechanical and optical properties, poor performance in terms of odor and taste, and they usually have poor compatibility between the main polymer phases, resulting in limited impact strength and heat deflection resistance. This poor performance is partly caused by PE with lower stiffness and melting point, which forms a continuous phase even when the PP concentration is as high as 65%, because the viscosity of the PE component in PCW is usually higher.

[0006] These drawbacks generally exclude the application of high-quality parts, and they only allow use in low-cost and undemanding applications.

[0007] Some studies have been conducted to improve the compatibility between PP and PE.

[0008] WO2019 / 091886A1 discloses a method of using a multiphase polypropylene composition or a random ethylene-propylene copolymer (EP-RACO) as a compatibilizer for recycled plastic blends. In terms of compatibilization performance, the multiphase copolymer composition seems less promising.

[0009] It has now been found that a composition comprising a specifically tailored polypropylene composition can be used as a compatibilizer for recycled PE / PP compositions, thereby imparting better properties, especially for the production of films. SUMMARY OF THE INVENTION

[0010] The present disclosure relates to polyolefin compositions, comprising:

[0011] (A) 60 to 95 wt% of a polyolefin component, which contains:

[0012] -(a1) 20 wt% to 80 wt% of an acrylonitrile-based polymer having an acrylonitrile content higher than 60 wt%

[0013] -(a2) 20 wt% to 80 wt% of a vinyl polymer having an ethylene content higher than 70 wt%;

[0014] (B) 5 to 40 wt% of a polypropylene composition, the polypropylene composition comprising:

[0015] -(b1) 35 to 65 wt%, preferably 40 to 60 wt%, of a polymer fraction, which comprises a propylene homopolymer, or a copolymer of propylene with one or more comonomers selected from ethylene and CH2=CHR α-olefins, where R is a C2-C8 alkyl group, or a mixture thereof; the copolymer contains at least 85 wt% of units derived from propylene, and

[0016] -(b2) 35 to 65 wt%, preferably 40 to 60 wt%, of a polymer fraction, which comprises a copolymer of ethylene with a comonomer selected from propylene and / or CH2=CHR α-olefins, where R is a C2-C8 alkyl group, the copolymer containing an amount of units derived from ethylene in the range of 25 to 40 wt%, preferably 28 to 35 wt%, the polypropylene composition (B) is further characterized by

[0017] - Melt flow rate (ISO 1133 230 °C / 2.16 kg) in the range of 0.1 to 5 g / 10 min, preferably 0.2 to 2.5 g / 10 min;

[0018] - The amount of the fraction soluble in xylene at room temperature (25 °C) is in the range of 35 to 60 wt%, preferably 40 to 55 wt%, the fraction having an intrinsic viscosity measured in tetralin at 135 °C in the range of 3.0 to 7.5 dl / g, preferably 4.0 to 6.5 dl / g; and,

[0019] - The total ethylene content measured according to the 13 C-NMR method described in the specification is in the range of 10 to 25 wt%, preferably 13 to 23 wt%;

[0020] In the said composition, the sum of a1) and a2) refers to the total weight of a1) and a2), which is 100; the sum of b1) and b2) refers to the total weight of b1) and b2), which is 100; and the sum of the amounts of (A) and (B) refers to the total weight of (A) and (B), which is 100. Detailed Description

[0021] As used herein, the term "copolymer" refers to polymers having two different repeating units in the chain and polymers having more than two different repeating units, such as terpolymers. "Ambient temperature or room temperature" herein refers to a temperature of about 25 °C.

[0022] As used herein in connection with a polymer or a polymer composition, the term "consisting essentially of" means that in addition to the mandatory components, other components may be present in the polymer or polymer composition, provided that the basic properties of the polymer or composition are not substantially affected by their presence. According to the present disclosure, examples of components that do not substantially affect its properties when present in conventional amounts in a polymer or polymer composition are catalyst residues, antistatic agents, melt stabilizers, light stabilizers, antioxidants, and antacids.

[0023] The characteristics of the components forming the polypropylene composition are not inseparably linked to each other. This means that a certain preferred level of one characteristic does not necessarily involve the same preferred level of the remaining characteristics of the same or different components. On the contrary, it is intended in the present disclosure that any component or sub-component (A) to (B) and any preferred range of the characteristics of the components (A) to (B) can be combined with any preferred range of one or more characteristics of the components (A) to (B) and with any possible additional components and their characteristics described in the present disclosure.

[0024] Preferably, based on the sum of (A) and (B), component (A) is used in an amount in the range of 65 to 95 wt%, more preferably 75 to 95 wt%; especially 80 to 95 wt%.

[0025] Preferably, based on the sum of (A) and (B), component (B) is used in an amount in the range of 5 to 35 wt%, more preferably 5 to 25 wt%; especially 5 to 20 wt%.

[0026] Preferably, based on the sum of a1) + a2), the amount of component a1) is in the range of 30 wt% to 70 wt%, preferably 40 wt% to 60 wt%, more preferably 45 wt% to 55 wt%. Preferably, it is selected from propylene-based polymers having a propylene content higher than 70 wt%; more preferably higher than 80 wt% and even more preferably higher than 90 to 100 wt%.

[0027] Preferably, based on the sum of a1) + a2), the amount of component (a2) is in the range of 30 wt% to 70 wt%, preferably 40 wt% to 60 wt%, more preferably 45 wt% to 55 wt%. Preferably, it is selected from vinyl polymers having an ethylene content higher than 70 wt%, preferably higher than 75 wt%; more preferably higher than 80 wt%, and even more preferably 90 wt% to 100%.

[0028] Component (A) preferably originates from waste materials that contain at least 80% by weight, usually at least 90% by weight, especially 80% by weight or 90% to 99% by weight of polyethylene or polypropylene or mixtures thereof, relative to the total weight of the components. The term "waste" is used to denote polymeric materials obtained from at least one cycle of processed finished products, as opposed to virgin polymers. Mixtures including recycled polypropylene and polyethylene blends are the main components.

[0029] As mentioned above, all kinds of polyethylene or polypropylene can be present. In particular, the polyethylene fraction can include one or more materials selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE).

[0030] The polypropylene fraction can include one or more polymeric materials selected from:

[0031] I) Isotactic or predominantly isotactic polypropylene homopolymers;

[0032] II) Random copolymers of propylene with ethylene and / or C4-C8 α-olefins (such as 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene), wherein the total comonomer content is from 0.05% to 20% by weight, or mixtures of said copolymers with isotactic or predominantly isotactic polypropylene homopolymers;

[0033] III) Multiphase copolymers that include one of a polypropylene homopolymer and / or the copolymer of item II), and an elastomeric fraction that includes a copolymer of ethylene with propylene and / or C4-C8 α-olefins, optionally containing trace amounts of dienes such as butadiene, 1,4-hexadiene, 1,5-hexadiene, ethylidene-1-norbornene.

[0034] Other polymeric materials that are usually present as impurities in component (A) are polystyrene, ethylene-vinyl acetate copolymers, and polyethylene terephthalate.

[0035] Other impurities that can be present in component (A) are metals (especially Al) and additives such as fillers and pigments.

[0036] Based on the total of (A + B), component (B) is preferably present in an amount in the range of 5 to 35 wt%, preferably 5 to 25 wt%; more preferably 5 wt% to 20 wt%.

[0037] Component (b1) is preferably selected from propylene homopolymers or propylene-ethylene copolymers containing 0.1 wt% to 6.0 wt%, preferably 0.5 wt% to 5.0 wt% of ethylene.

[0038] Component (b2) is preferably selected from copolymers of ethylene and propylene containing an amount of units derived from ethylene in the range of 25 to 40 wt%, preferably 28 to 35 wt%.

[0039] As described above, the polypropylene composition (B) is further characterized by

[0040] - The melt flow rate (ISO 1133 230 °C / 2.16 kg) ranges from 0.1 to 5 g / 10 min, preferably 0.2 to 2.5 g / 10 min, and more preferably 0.3 to 2.0 g / 10 min;

[0041] - The amount of the fraction soluble in xylene at room temperature (25 °C) is in the range of 35 to 60 wt%, preferably 40 to 55 wt%, more preferably 45 to 55 wt%, and the fraction has an intrinsic viscosity measured in tetralin at 135 °C in the range of 3.0 to 7.5 dl / g, preferably 4.0 to 6.5 dl / g, more preferably 4.5 to 6.5 dl / g; and,

[0042] - The total ethylene content measured by the NMR method described in the specification is in the range of 10 to 25 wt%, preferably 13 to 23 wt%, more preferably 15 to 23 wt%.

[0043] The melt flow rate (ISO 1133 230 °C / 2.16 kg) of the entire polyolefin composition can range from 0.5 to 30 g / 10 min, preferably 0.5 to 20 g / 10 min, especially 0.5 to 15 g / 10 min.

[0044] The polyolefin composition of the present disclosure provides excellent compatibility between the polyethylene and polypropylene parts of component (A), such that its mechanical properties and the appearance of the manufactured products enable them to be used in a wide range of applications, and especially for the production of films, including single-layer or multi-layer cast films, blown films, and biaxially oriented films, where the number of gels in the film is reduced.

[0045] In particular, the polyolefin composition of the present disclosure provides an excellent balance between the elastic modulus and the Charpy resistance at 23 °C, especially when the components (a1) and (a2) are sources of plastic waste. For compositions in which the fraction (a2) is greater than (a1), the elastic modulus is equal to or higher than 850 N / mm 2 , and the ratio between the value of the elastic modulus and the Charpy resistance at 23 °C is lower than 12. If an inorganic additive such as talc is added, the elastic modulus is equal to or higher than 950 N / mm 2 , and the ratio between the value of the elastic modulus and the Charpy resistance at 23 °C is lower than 15.

[0046] For compositions in which the fraction (a1) is greater than (a2), the elastic modulus is equal to or higher than 950 N / mm 2 , and the ratio between the value of the elastic modulus and the Charpy resistance at 23 °C is lower than 65.

[0047] The polypropylene composition (B) can be prepared by polymerization in successive polymerization stages, where each subsequent polymerization is carried out in the presence of the polymeric material formed in the previous polymerization reaction. The polymerization stages can be carried out in the presence of a Ziegler-Natta catalyst. According to a preferred embodiment, all polymerization stages are carried out in the presence of a catalyst comprising the reaction product between:

[0048] i) a solid catalyst component comprising Ti, Mg, Cl and at least one internal electron donor compound;

[0049] ii) an alkylaluminum compound, and

[0050] iii) an external electron donor compound having the following general formula:

[0051] (R 7 )a(R 8 )bSi(OR 9 )c, where a and b are integers from 0 to 2, c is an integer from 1 to 4, and the sum (a + b + c) is 4; R 7 , R 8 , and R 9 are alkyl, cycloalkyl or aryl groups having 1 to 18 carbon atoms optionally containing heteroatoms.

[0052] The internal donor is preferably selected from esters of mono- or dicarboxylic organic acids, such as benzoates, malonates, phthalates and certain succinates. Examples of internal donors are described in US 4522930A, EP 045977A2 and international patent applications WO00 / 63261 and WO 01 / 57099. Particularly suitable are phthalates, such as diisobutyl phthalate, dioctyl phthalate and diphenyl phthalate and benzyl butyl phthalate.

[0053] The particles of the solid component (i) can have a substantially spherical morphology and an average diameter between 5 and 150 μm, preferably between 20 and 100 μm and more preferably between 30 and 90 μm. By particles having a substantially spherical morphology is meant those in which the ratio between the major axis and the minor axis is equal to or less than 1.5, and preferably less than 1.3.

[0054] According to one method, the solid catalyst component (i) can be prepared by reacting: a titanium compound of the formula Ti(OR)q-yXy, where q is the valence of titanium and y is a number between 1 and q, preferably TiCl4, magnesium chloride derived from an adduct of the formula MgCl2·pROH, where p is a number between 0.1 and 6, preferably between 2 and 3.5, and R is a hydrocarbyl group having 1 to 18 carbon atoms. The adduct can be suitably prepared in spherical form by mixing the alcohol and magnesium chloride and operating under stirring conditions at the melting temperature of the adduct (100 - 130 °C). Then, the adduct is mixed with an inert hydrocarbon immiscible with the adduct, thereby producing an emulsion which is rapidly quenched, resulting in the solidification of the adduct in the form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP 4,399,054 and USP 4,469,648. The adduct thus obtained can be reacted directly with the Ti compound, or it can be pre-treated by thermal controlled dealcoholation (80 - 130 °C) to obtain an adduct in which the molar number of alcohol is generally less than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or as such) in cold TiCl4; the mixture is heated to 80 - 130 °C and maintained at this temperature for 0.5 to 2 hours. The treatment with TiCl4 can be carried out one or more times. The electron donor compound can be added in the desired proportion during the treatment with TiCl4.

[0055] The alkylaluminum compound (ii) is preferably selected from trialkylaluminum compounds such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. Alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides such as AlEt2Cl and Al2Et3Cl3 can also be used, possibly in the form of a mixture with the above-mentioned trialkylaluminums. The Al / Ti ratio is higher than 1 and can preferably range between 50 and 2000.

[0056] Particularly preferred is the silicon compound (iii), where a is 1, b is 1, c is 2, R 7 and R 8 in which at least one of them is selected from branched alkyl, cycloalkyl or aryl groups having 3 to 10 carbon atoms, optionally containing heteroatoms, and R 9 is C1-C 10Alkyl groups, especially methyl groups. Examples of such preferred silicon compounds are methylcyclohexyldimethoxysilane (C donor), diphenyldimethoxysilane, methyl-tert-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), diisopropyldimethoxysilane, (2-ethylpiperidinyl)tert-butyldimethoxysilane, (2-ethylpiperidinyl)tert-hexyldimethoxysilane, (3,3,3-trifluoro-n-propyl)(2-ethylpiperidinyl)dimethoxysilane, methyl(3,3,3-trifluoro-n-propyl)dimethoxysilane. In addition, silicon compounds in which a is 0, c is 3, R 8 is a branched or cycloalkyl group optionally containing a heteroatom and R 9 is methyl are also preferred. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, tert-butyltrimethoxysilane, and trimethoxysilane.

[0057] The amount of the external electron donor compound (iii) is such that the molar ratio between the organoaluminum compound and the external electron donor compound (iii) is from 0.1 to 200, preferably from 1 to 100, and more preferably from 3 to 50.

[0058] Examples of the polymerization process for preparing the composition can be found in EP-A-472946, the relevant part of which is incorporated herein by reference.

[0059] Preferably, all polymerization stages are preferably carried out in the gas phase. The reaction temperature in the polymerization stage for preparing the polymer fraction (b1) and the reaction temperature in the polymerization stage for preparing the copolymer fraction (b2) can be the same or different, and are preferably from 40 °C to 90 °C; more preferably, the reaction temperature range is from 50 to 80 °C in the preparation of fraction (b1), and from 40 to 80 °C in the preparation of component (b2). The pressure in the gas phase for the polymerization stages for preparing fractions (b1) and (b2) is from 5 to 30 bar. The residence time with respect to the two stages depends on the desired ratio between fractions (b1) and (b2), and can generally be in the range of 15 minutes to 8 hours. Conventional molecular weight regulators known in the art, such as chain transfer agents (e.g., hydrogen or ZnEt2), can be used.

[0060] If desired, the final composition (B) can be chemically treated with an organic peroxide to reduce the average molecular weight and increase the melt flow index to a value required for a specific application.

[0061] In addition, the final composition (B) can be subjected to a grafting process in the presence of a polar monomer (such as maleic anhydride) to make it more compatible with polymers containing a large amount of polar monomers. When composition (A) is derived from plastic waste, the polar monomer can be present as a minor component in composition (A).

[0062] The entire propylene composition of the present disclosure can be obtained by mechanical blending of components (A) and (B) according to conventional techniques.

[0063] According to a preferred preparation method, component (B) is mechanically blended with a preformed polypropylene composition (A) comprising components (a) and (b) associated together by a sequential copolymerization method that has been disclosed.

[0064] The final composition comprising components (A) and (B) can be added together with conventional additives, fillers, and pigments commonly used in olefin polymers, such as nucleating agents, extender oils, mineral fillers, and other organic and inorganic pigments. In particular, adding inorganic fillers, such as talc, calcium carbonate, and mineral fillers, also improves some mechanical properties, such as flexural modulus and HDT. Talc can also have a nucleating effect.

[0065] The nucleating agent can be added, for example, in an amount in the range of 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, based on the total weight, to the composition of the present disclosure.

[0066] The following examples are given to illustrate and not limit the present disclosure.

[0067] Examples

[0068] Characterization

[0069] Xylene-soluble (XS) fraction at 25 °C

[0070] Solubility in xylene: Determined as follows:

[0071] Introduce 2.5 g of the polymer and 250 ml of xylene into a glass flask equipped with a refrigerator and a magnetic stirrer. Raise the temperature to the boiling point of the solvent within 30 minutes. Then keep the resulting clear solution under reflux and stir for 30 minutes. Then keep the closed flask in an ice-water bath for 30 minutes, and then in a constant-temperature water bath at 25 °C for 30 minutes. Filter the resulting solid on a fast filter paper. Pour 100 ml of the filtrate into a pre-weighed aluminum container, and heat it on a hot plate under a nitrogen stream to remove the solvent by evaporation. Then keep the container in an oven at 80 °C under vacuum until a constant weight is reached. Then calculate the weight percentage of the polymer soluble in xylene at room temperature.

[0072] The content of the xylene-soluble fraction is expressed as a percentage of the original 2.5 grams, and then, by difference (complemented to 100%), as the xylene-insoluble percentage (%);

[0073] Melt flow rate (MFR)

[0074] Unless otherwise specified, it is measured according to ISO 1133 at 230 °C and a load of 2.16 kg.

[0075] Intrinsic viscosity (IV)

[0076] The sample was dissolved in tetralin at 135 °C and then poured into a capillary viscometer. The viscometer tube (Ubbelohde type) was surrounded by a cylindrical glass jacket; this setup allowed temperature control with a circulating thermostatic liquid. The downward passage of the meniscus was timed by a photoelectric device.

[0077] The passage of the meniscus in front of the upper lamp started a counter with a quartz crystal oscillator. The counter was stopped when the meniscus passed the lower lamp, and the efflux time was recorded: this was converted to an intrinsic viscosity value by Huggins' equation (Huggins, M. L., J. Am. Chem. Soc., 1942, 64, 2716), provided that the flow time of the pure solvent was known under the same experimental conditions (same viscometer and same temperature). [η] was determined using a single polymer solution.

[0078] Ethylene (C2) content

[0079] of the propylene / ethylene copolymer 13 13C NMR

[0080] 13 13C NMR spectra were obtained on a Bruker AV-600 spectrometer equipped with a cryoprobe, operating at 160.91 MHz in Fourier transform mode at 120 °C.

[0081] The peak of S at 29.9 ppm ββ The peak of carbon (nomenclature according to C. J. Carman, R. A. Harrington, and C. E. Wilkes, Macromolecules, 1977, 10, 536, "Monomer Sequence Distribution in Ethylene-Propylene Rubber by 13C NMR Measurements. 3. Use of Reaction Probability Models") was used as an internal reference. The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at a concentration of 8% wt / v at 120 °C. Each spectrum was obtained using a 90° pulse, a 15 s delay between pulses, and CPD to remove 1H-13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz.

[0082] The evaluation of the spectrum distribution, triplet distribution, and composition was made according to Kakugo (M. Kakugo, Y. Naito, K. Mizunuma, and T. Miyatake, Macromolecules 1982, 15, 4, 1150–1152, "Carbon-13 NMR Determination of Monomer Sequence Distribution in Ethylene-Propylene Copolymers Prepared with δ-Titanium Trichloride-Diethylaluminum Chloride") using the following equations:

[0083] PPP = 100T ββ / S PPE = 100T βδ / S EPE = 100T δδ / S

[0084] PEP = 100S ββ / S PEE = 100S βδ / S EEE = 100(0.25S γδ +0.5S δδ ) / S

[0085] S = T ββ +T βδ +T δδ +S ββ +S βδ +0.25S γδ +0.5S δδ

[0086] The molar percentage of ethylene content was evaluated using the following equation:

[0087] E%mol = 100 * [PEP + PEE + EEE] The weight percentage of ethylene content was evaluated using the following equation:

[0088]

[0089] where P%mol is the molar percentage of propylene content, and MW E and MW P are the molecular weights of ethylene and propylene, respectively.

[0090] The product of the reaction ratios r1r2 was calculated according to Carman (C. J. Carman, R. A. Harrington, and C. E. Wilkes, Macromolecules, 1977; 10, 536) as:

[0091]

[0092] The stereoregularity of the propylene sequence was calculated as the mm content from the ratio of PPP mmT ββ (28.90 - 29.65 ppm) and total T ββ (29.80 - 28.37 ppm).

[0093] Samples for mechanical testing

[0094] Samples were obtained in accordance with ISO 1873-2:2007.

[0095] Charpy impact tests were determined in accordance with ISO 179-1eA and ISO 1873-2.

[0096] Yield elongation: Measured in accordance with ISO 527.

[0097] Elongation at break: Measured in accordance with ISO 527

[0098] Breaking stress: Measured in accordance with ISO 527.

[0099] Tensile modulus in accordance with ISO 527-2,

[0100] Tear resistance was measured on 1 mm thick extruded sheets in accordance with method ASTM D 1004. Crosshead speed: 51 mm / min; V-notch die-cut specimens.

[0101] Shore D was measured in accordance with method ISO 868 (15 s) on injection molded, compression molded plates and extruded sheets

[0102] Melting point and crystallization point

[0103] The melting point was measured on samples weighing 5 to 7 mg under cooling and heating under an inert N2 flow at a scanning rate of 20 °C / min using a DSC instrument conforming to ISO 11357-3. Instrument calibration was carried out using indium.

[0104] Example

[0105] Preparation of component (B)

[0106] Catalyst system and prepolymerization:

[0107] Before introducing it into the polymerization reactor, the above solid catalyst component (ZN107) was contacted with triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) at 30 °C for 9 minutes, with a TEAL / DCPMS weight ratio of about 15 and a TEAL / solid catalyst component weight ratio of about 4.

[0108] The catalyst system was then subjected to prepolymerization by holding it in a liquid propylene suspension at 50 °C for about 75 minutes and then introducing it into the first polymerization reactor.

[0109] Polymerization

[0110] The polymerization is carried out in a series of three gas-phase reactors in continuous mode, and these gas-phase reactors are equipped with means for transferring the product from the first reactor to the second reactor. The propylene-based polymer (A) is prepared in the first gas-phase polymerization reactor by feeding a pre-polymerized catalyst system, hydrogen (molecular weight regulator), and propylene, all in gaseous state, in continuous and constant flow. The propylene-based polymer (A) from the first reactor is discharged in continuous flow, and after the unreacted monomers have been removed, it is introduced into the second gas-phase reactor in continuous flow together with a quantitatively constant flow of hydrogen and ethylene, all in gaseous state. The ethylene copolymer (B) is prepared in the second reactor. The product from the second reactor is discharged in continuous flow, and after the unreacted monomers have been removed, it is introduced into the third gas-phase reactor in continuous flow together with a quantitatively constant flow of hydrogen, ethylene, and propylene, all in gaseous state. The ethylene-propylene polymer (C) is prepared in the third reactor. The polymerization conditions, the molar ratios of the reactants, and the composition of the resulting copolymers are shown in Table 1. The polymer particles leaving the third reactor are subjected to steam treatment to remove the reactive monomers and volatile substances, and then dried. Thereafter, the polymer particles are mixed with a stabilizing additive composition in a twin-screw extruder Berstorff ZE 25 (length / diameter ratio of the screw: 34) and extruded under the following conditions in a nitrogen atmosphere:

[0111] Rotational speed: 250 rpm;

[0112] Extruder output: 15 kg / hour;

[0113] Melting temperature: 245 °C.

[0114] The stabilizing additive composition comprises the following components:

[0115] - 0.1 wt% of 1010;

[0116] - 0.1 wt% of 168; and

[0117] - 0.04 wt% of DHT-4A (hydrotalcite);

[0118] wherein all percentage amounts refer to the total weight of the polymer and the stabilizing additive composition.

[0119] 1010 is 2,2-bis[3-[,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)-1-oxopropoxy]methyl]-1,3-propanediyl-3,5-bis(1,1-dimethylethyl)-4-hydroxybenzoate, and 168 is tris(2,4-di-tert-butylphenyl) phosphite. The properties of the polymer compositions reported in Table 2 were obtained from measurements on the extruded polymers that make up the stable ethylene polymer compositions according to certain embodiments disclosed herein.

[0120] Table 1 - Polymerization Conditions

[0121]

[0122] Examples 1 and Comparative Examples 1 to 3

[0123] In this series of examples, mixtures of different ratios of recycled PE (QCP5603) and recycled PP (QCP 300P) were introduced into an extruder (Berstorff extruder), where they were mixed with 10% (based on the total amount of polyolefins) of a multiphase composition used as a compatibilizer and 1000 ppm of M.S. 168 used as an additive. The polymer pellets were extruded in a twin-screw extruder at a rotational speed of 250 rpm and a melting temperature of 200 °C to 250 °C under a nitrogen atmosphere. The characterization of the resulting compositions is reported in Table 2.

[0124] The compatibilizers used were:

[0125] B1 - Component B prepared in Test 1

[0126] B2 - Component B prepared in Test 2

[0127] CC1 - Comparative compatibilizer prepared according to Example 1 of WO2020 / 182436

[0128] CC2 - Comparative compatibilizer prepared according to Example 1 of WO03 / 011962 after visbreaking at 15 g / 10 minutes.

[0129] Table 2

[0130]

[0131] Examples 2 and Comparative Examples 4 to 5

[0132] In this series of examples, the same method as disclosed in Examples 1 and Comparative Examples 1 to 3 was followed, except that talc was added as an additional component. The characterization of the resulting compositions is reported in Table 3.

[0133] Table 3

[0134]

[0135] Examples 3 and Comparative Examples 6 to 8

[0136] In this series of examples, the same method as disclosed in Example 1 and Comparative Examples 1 to 3 was followed, except that the relative amounts of recycled PE (QCP5603) and recycled PP (QCP 300P) were varied. The characterization of the obtained compositions is reported in Table 4.

[0137] Table 4

[0138]

[0139]

[0140] Examples 4 to 5 and Comparative Examples 9 to 10

[0141] In this series of examples, the same method as disclosed in Example 1 and Comparative Examples 1 to 3 was followed. Except that a blend (A) of 50 wt% Hostalen GF 9055F (virgin commercial high density polyethylene sold by LyondellBasell) and 50 wt% Moplen HP561R (virgin polypropylene homopolymer sold by LyondellBasell) was prepared. The characterization of the obtained compositions is reported in Table 5.

[0142] In addition, the cast films obtained from the above compositions were tested and characterized. The results are reported in Table 6.

[0143] The gel count test was carried out on the cast film Collin extrusion line diameter with a 25 mm single screw, having the following characteristics:

[0144] Single screw L / D 25

[0145] Temperature profile

[0146] Cylinder 200 (near the hopper) -> 230 °C (at the end of the extruder, before the die inlet)

[0147] Die 240 °C

[0148] Die width 150 mm

[0149] Cooling roll 30 °C

[0150] Film speed 3.0 m / minute

[0151] Film thickness 50 microns

[0152] Inspection area 1 m 2

[0153] OCS FS5 gel count units on a 4 cm wide stripe

[0154] The elongation at break of the cast film was measured in the machine direction (MD) and the transverse direction (TD) according to ASTM D 882.

[0155] Table 5

[0156]

[0157] CC3 is a multiphase TPO (thermoplastic polyolefin) polypropylene grade with a total ethylene content of 11.0 wt%; the fraction soluble in xylene at 25 °C is 29 wt%. The intrinsic viscosity of the fraction soluble in xylene at 25 °C is 6.8 dl / g, and the MFR is 1.7 g / 10 min. It was obtained by following the process settings and similar conditions disclosed in Examples 1 to 4 of WO2004 / 08705.

[0158] Table 6

[0159]

[0160]

Claims

1. A polyolefin composition, comprising: (A) 60 to 95 wt% of a polyolefin component, which contains: -(a1) 20 wt% to 80 wt% of a propylene-based polymer with a propylene content higher than 60 wt% -(a2) 20 wt% to 80 wt% of an ethylene-based polymer with an ethylene content higher than 70 wt%; (B) 5 to 40 wt% of a polypropylene composition, the polypropylene composition comprising: -(b1) 35 to 65 wt% of a polymer fraction, which comprises a propylene homopolymer, or a copolymer of propylene and one or more comonomers selected from ethylene and CH2=CHR α-olefins, where R is a C2-C8 alkyl group, or a mixture thereof; the copolymer contains at least 85 wt% of units derived from propylene, and -(b2) 35 to 65 wt% of a polymer fraction, which comprises a copolymer of ethylene and propylene, the copolymer containing an amount of units derived from ethylene in the range of 25 to 40 wt%, the polypropylene composition (B) is further characterized in that - the melt flow rate ISO 1133 230 °C / 2.16 kg ranges from 0.1 to 5 g / 10 min; - the amount of the fraction soluble in xylene at room temperature of 25 °C is in the range of 35 to 60 wt%, and the fraction has an intrinsic viscosity measured in tetralin at 135 °C in the range of 3.0 to 7.5 dl / g; and, - 13 The total ethylene content measured by the C-NMR method is in the range of 13 to 23% by weight; In the composition, the sum of (a1) and (a2) refers to the total weight of (a1) and (a2), which is 100, the sum of (b1) and (b2) refers to the total weight of (b1) and (b2), which is 100, and the sum of the amounts of (A) and (B) refers to the total weight of (A) and (B), which is 100.

2. The polyolefin composition according to claim 1, wherein: Component (A) is used in an amount in the range of 65 to 95 wt%; and component (B) is used in an amount in the range of 5 to 35 wt%.

3. The polyolefin composition according to claim 1, wherein, based on the sum of a1) + a2), the amount of component a1) is in the range of 30 wt% to 70 wt%.

4. The polyolefin composition according to claim 1, wherein component (a1) is selected from propylene-based polymers having a propylene content higher than 70 wt%.

5. The polyolefin composition according to claim 1, wherein, based on the sum of (a1) + (a2), the amount of component (a2) is in the range of 30 wt% to 70 wt%.

6. The polyolefin composition according to claim 1, wherein component (a2) is selected from vinyl polymers having an ethylene content higher than 70 wt%.

7. The polyolefin composition according to claim 1, wherein component (A) is derived from waste material containing not less than 80% by weight of polyethylene or polypropylene or a mixture thereof relative to the total weight of the component.

8. The polyolefin composition according to claim 1, wherein component (b1) is present in an amount of 40 to 60% by weight relative to component (B) and is selected from propylene homopolymers.

9. The polyolefin composition according to claim 1, wherein component (b2) is present in an amount of 40 to 60% by weight relative to component (B) and is selected from copolymers of ethylene with propylene and / or CH2 = CHR α-olefins, where R is a C2-C8 alkyl group, and the copolymer contains an amount of units derived from ethylene in the range of 28 to 35% by weight.

10. The polyolefin composition according to claim 1, wherein the polypropylene composition (B) has a melt flow rate ISO 1133 of 0.2 to 2.5 g / 10 min at 230 °C / 2.16 kg.

11. The polyolefin composition according to claim 1, wherein the amount of the fraction of the polypropylene composition (B) soluble in xylene at room temperature of 25 °C is in the range of 40 to 55% by weight, and the fraction has an intrinsic viscosity in the range of 4.0 to 6.5 dl / g measured in tetralin at 135 °C.

12. The polyolefin composition according to claim 1, wherein the polypropylene composition (B) has 13 a total ethylene content in the range of 13 to 23% by weight measured by C-NMR method.

13. The polyolefin composition according to claim 1, wherein the melt flow rate of the entire polyolefin composition at 230 °C / 2.16 kg according to ISO 1133 is in the range of 0.5 to 30 g / 10 min.

14. The polyolefin composition according to claim 1, wherein: -(b1) is 40 to 60 wt% of a polymer fraction, which comprises a propylene homopolymer, or a copolymer of propylene and one or more comonomers selected from ethylene and CH2=CHR α-olefins, where R is a C2-C8 alkyl group, or a mixture thereof; the copolymer contains at least 85 wt% of units derived from propylene; and / or -(b2) is 40 to 60 wt% of a polymer fraction, which comprises a copolymer of ethylene and propylene, the copolymer containing an amount of units derived from ethylene in the range of 25 to 40 wt%; and / or - the polypropylene composition (B) is further characterized in that the melt flow rate ISO 1133 230 °C / 2.16 kg ranges from 0.2 to 2.5 g / 10 min; and / or - the amount of the fraction soluble in xylene at room temperature of 25 °C in the polyolefin composition is in the range of 40 to 55 wt%, and the fraction has an intrinsic viscosity measured in tetralin at 135 °C in the range of 3.0 to 7.5 dl / g.

15. The polyolefin composition according to claim 14, wherein: In (b2), the copolymer contains an amount of units derived from ethylene in the range of 28 to 35 wt%.

16. The polyolefin composition according to claim 14, wherein the fraction soluble in xylene at room temperature of 25 °C has an intrinsic viscosity in the range of 4.0 to 6.5 dl / g measured in tetralin at 135 °C.

17. The polyolefin composition according to claim 2, wherein component (A) is used in an amount in the range of 75 to 95 wt%; and / or component (B) is used in an amount in the range of 5 to 25 wt%.

18. The polyolefin composition according to claim 3, wherein based on the sum of a1)+a2), the amount of component a1) is in the range of 40 wt% to 60 wt%.

19. The polyolefin composition according to claim 4, wherein component (a1) is selected from propylene-based polymers having a propylene content higher than 80 wt%.

20. The polyolefin composition according to claim 19, wherein component (a1) is selected from propylene-based polymers having a propylene content higher than 90 wt% to 100 wt%.

21. The polyolefin composition according to claim 5, wherein based on the sum of (a1)+(a2), the amount of component (a2) is in the range of 40 wt% to 60 wt%.

22. The polyolefin composition according to claim 21, wherein based on the sum of (a1)+(a2), the amount of component (a2) is in the range of 45 wt% to 55 wt%.

23. The polyolefin composition according to claim 6, wherein component (a2) is selected from vinyl polymers having an ethylene content higher than 75 wt%.

24. The polyolefin composition according to claim 23, wherein component (a2) is selected from vinyl polymers having an ethylene content higher than 80 wt%.

25. The polyolefin composition according to claim 24, wherein component (a2) is selected from vinyl polymers having an ethylene content of 90 wt% to 100%.

26. The polyolefin composition according to claim 7, wherein component (A) is derived from waste containing at least 90% by weight of polyethylene or polypropylene or a mixture thereof, based on the total weight of the component.

27. The polyolefin composition according to claim 7, wherein component (A) is derived from waste containing 80% to 99% by weight of polyethylene or polypropylene or a mixture thereof, based on the total weight of the component.

28. The polyolefin composition according to claim 27, wherein component (A) is derived from waste containing 90% to 99% by weight of polyethylene or polypropylene or a mixture thereof, based on the total weight of the component.

29. The polyolefin composition according to claim 13, wherein the melt flow rate of the entire polyolefin composition according to ISO 1133 at 230 °C / 2.16 kg ranges from 0.5 to 20 g / 10 min.

30. The polyolefin composition according to claim 29, wherein the melt flow rate of the entire polyolefin composition according to ISO 1133 at 230 °C / 2.16 kg ranges from 0.5 to 15 g / 10 min.

31. An extruded or molded article obtained from the polyolefin polymer composition according to claim 1.

32. The extruded article according to claim 31, which is a single-layer or multi-layer cast film, blown film or biaxially oriented film.

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