High-strength cast polypropylene

Description

"HIGH-STRENGTH CAST POLYPROPYLENE"

[0001] The present invention relates to a high-strength cast polypropylene (HMSPP) comprising derivable units of at least one polyunsaturated fatty acid, a process for preparing said high-strength cast polypropylene (HMSPP), as well as an article comprising said high-strength cast polypropylene (HMS-PP).

[0002] In the case of propylene-based polymer compositions being used to form shaped objects, it is necessary that the compositions have a sufficiently high molten material strength to enable the compositions to be molded into the desired shape. This is, for example, the case when propylene-based polymer compositions are shaped into objects through processes in which the composition is heated above its melting temperature and subsequently shaped into the desired objects. In this process, high shape stability of the propylene-based polymer composition is required at the temperature at which the object is molded. The propylene-based polymer composition needs to be able to maintain its shape in the molten state under these temperature conditions before solidification by cooling occurs.These objects, which can be prepared using propylene-based polymer compositions, may include, for example, foam structures.

[0003] A common method for producing foam structures using propylene-based polymer compositions, as described in “Polypropylene foams”, Ratzsch et al. , Petition 870230098439, dated 07 / 11 / 2023, page 7 / 264 2 / 67 Springer, 1999, DOI: 0,007 / 978-94-01-4421-6-86, p. 635642, is a process that comprises the following steps: (i) placing the propylene-based polymer composition in a molten condition; (ii) introducing pockets of gaseous material into the propylene-based molten polymer composition to form a propylene-based molten polymer composition comprising foam cells; (iii) molding the propylene-based molten polymer composition comprising foam cells into the desired shape comprising a foam structure; and (iv) solidifying the shaped foam structure by cooling to below the melting point of the propylene-based polymer composition.

[0004] Generally, these steps are performed in the order presented. A critical element in this process is the formation of foam cells in step (ii). Depending on the nature of the material processed, the foam structure may comprise a certain number of closed cells. In the context of the present invention, closed cells can be understood as pockets of gaseous material that are surrounded on all sides by closed cell walls, so that the gaseous material in each cell is not in contact with the gaseous material in another cell. These cell walls may comprise, for example, a propylene-based polymer composition.

[0005] For certain applications, it is desirable that the foam structure comprise a certain high fraction of closed cells. A high fraction of closed cells can contribute to the thermal insulation value of a Petition 870230098439, dated 07 / 11 / 2023, page 8 / 264 3 / 67 foam structure. Furthermore, a high fraction of closed cells can contribute to the strength of a foam structure, such as in terms of flexural modulus and tensile strength. Additionally, it is desirable that these foam structures have a certain low density. For example, the density of foam structures can be less than or equal to 100 kg / m3, alternatively less than or equal to 80 kg / m3. Foam structures that have such a low density comply with weight reduction requirements for applications such as meat or fruit trays.

[0006] Another important characteristic is that the temperature range in which foam structures with the desired high closed-cell fraction and low density can be produced by extrusion foam production methods is sufficiently wide. This temperature range is also called the foamability window. Preferably, the foamability window is greater than or equal to 5 °C. If the foamability window is too narrow, this represents a significant load on the foam processing equipment, since it is necessary to avoid fluctuations in the processing temperature. Fluctuations beyond the foamability window of a material to be foamed can lead to a material that is out of specification, which is unsuitable for commercial sale because it does not meet quality requirements.

[0007] To achieve the above properties, the propylene-based polymer composition needs to have a sufficiently high melt strength. The melt strength is an indication of the extent to which Petition 870230098439, dated 07 / 11 / 2023, page 9 / 264 4 / 67 which individual polymer molecules are able to maintain their positions relative to each other under conditions where the polymer composition is in a molten state.

[0008] A high-strength cast polypropylene is branched and therefore differs from a linear polypropylene in that the polypropylene backbone covers the side chains, whereas an unbranched polypropylene, i.e., a linear polypropylene, does not cover the side chains. Such long-chain branching is known to drastically modify the rheological behavior of polypropylene, for example, elongational and shear viscosity.

[0009] Three main routes are known for producing branched polypropylenes with the properties required for low-density foam on a commercial scale: A. Irradiation of polypropylene without coupling / sensitizing agent; B. Reactive extrusion of polypropylene using low-temperature peroxide / peroxycarbonate alone or in combination with a coupling agent; C. Polymerization of propylene and oligomers using special catalysts.

[0010] Route B has disadvantages stemming from the addition of peroxide as a radical source or coupling agent. The disadvantages of route C stem from the special catalyst and special polymerization conditions required, as well as the small production volumes compared to the typical size of commercial polymerization reactors.

[0011] Route A is the most preferred route in terms of product purity, but ensuring product quality in Petition 870230098439, dated 07 / 11 / 2023, page 10 / 264 5 / 67 Irradiation processes are a challenge, since active macroradicals tend to initiate viscosity reactions.

[0012] Document EP 0 190 889 discloses a process for producing branched polypropylene by irradiating PP flakes under reduced oxygen in the presence of low levels of antioxidants without a coupling agent. The dose range is revealed to be from 0.1 to 1000 kGy / min, and it is disclosed that the ionizing radiation must have sufficient energy to penetrate to the desired extent into the mass of linear propylene polymer material being irradiated. It is also disclosed that an acceleration potential (for an electron generator) of 500 to 4000 kV and a dose of 10 to 90 kGy are used. After the irradiation step, the irradiated material is heated in an extruder to deactivate macroradicals.

[0013] Documents EP 0 519 386 and EP 0 634 441 disclose a process similar to document EP 0 190 889 for producing a high-strength propylene polymer and copolymers from high-energy radiation-melted polypropylene flakes containing antioxidants. Documents US 5 047 446 and US 4 916 198 disclose a production process similar to EP 0 190 889 emphasizing two thermal deactivation steps after irradiation.

[0014] Document EP 0 678 527 (Chisso 1995) discloses a process for producing a modified polypropylene in which polypropylene and a crosslinking agent mixture are irradiated with ionizing radiation in order to generate an absorbed dose of 1 to 20 kGy, with subsequent heat treatment of the resulting material.

[0015] Document WO 97 / 08216 discloses a method for Petition 870230098439, dated 07 / 11 / 2023, page 11 / 264 6 / 67 produce diene-modified propylene polymers that are irradiated. It is revealed that the irradiation is preferably carried out using E-beam or gamma radiation at a dose of about 1 to about 20 Mrad for a few seconds. It is revealed that polypropylene can be copolymerized with a diene using a metallocene catalyst and then irradiated to cause chain extension.

[0016] Documents EP 0 799 839 and EP 0 351 866 also present similar disclosures to document EP 0 634 441 and reveal the use of an electron generator with an acceleration potential of 500 to 4000 kV.

[0017] Document EP 0 451 804 discloses a method for increasing the molecular weight of syndiotactic polypropylene by irradiation in the absence of oxygen. This descriptive report does not disclose any energy range for irradiation. The irradiation dose can be from 0.1 to 50 Mrad. After irradiation, the polypropylene can be heated.

[0018] Document EP 0 787 750 discloses a process for producing branched polypropylenes by irradiation in the presence of branching agents such as butadiene or diacrylates at a dose between 2 and 8 Mrd.

[0019] US patent 5,554,668 discloses a process for irradiating polypropylene to increase its molten strength. An increase in molten strength is achieved by decreasing the melt flow rate, also known as the melt index. It is disclosed that a linear propylene polymeric material is irradiated with high-energy ionizing radiation, preferably an electron beam, at a dose rate in the range of about 1 to 1 χ¹⁰⁴Mrads per minute for a sufficient period of time. Petition 870230098439, dated 07 / 11 / 2023, page 12 / 264 7 / 67 to achieve a substantial amount of chain scission of the linear propylene polymer molecule, but insufficient to cause gelation of the material. After that, the material is held for a sufficient period of time for a significant amount of long-chain branching to form. Finally, the material is treated to substantially deactivate all free radicals present in the irradiated material. It is revealed that, for an electron beam, electrons are transmitted from an electron generator with an acceleration potential (i.e., an energy) of 500 to 4,000 kV. Typically, the polypropylene material to be irradiated is in particle form and is transported on a conveyor belt beneath an electron beam generator that continuously irradiates the polypropylene particles as they are translated down the conveyor belt.The resulting polypropylene improved the strength of the molten material, as represented by a decrease in the melt flow rate. A disadvantage of the process revealed in US patent 5,554,668 is that the production rate of irradiated polypropylene is relatively low, due to the fact that the conveyor belt speed is low and only a small volume of material is processed. This results in difficulties in the commercial deployment of the process. Furthermore, the descriptive report reveals the use of a very wide range of dose rates, i.e., from 1 to 1 χ¹⁰⁴ Mrads per minute. High dose rates greater than about 40 Mrad can result in a substantially fully cross-linked structure of the polypropylene. Such a high cross-linked structure, however, is difficult to achieve. Petition 870230098439, dated 07 / 11 / 2023, page 13 / 264 8 / 67 processing.

[0020] Several attempts have been made to find a process for producing branched polypropylene by pellet irradiation as handling polypropylene powder presents several disadvantages in logistics and safety risks from dust explosions.

[0021] Document EP 0 520 773 discloses a expandable polyolefin resin composition that optionally includes polypropylene blended with polyethylene. To prepare a crosslinked foam, a sheet of expandable resin composition is irradiated with ionizing radiation to crosslink the resin. The ionizing radiation may include electron beams at a dose of 1 to 20 Mrad. It is disclosed that crosslinking auxiliary agents may be used that include a bifunctional monomer, exemplified in document EP 1 297 031 by 1,9-nonanediol dimethacrylate.

[0022] Document EP 0 519 341 discloses the grafting of vinyl monomers onto particulate olefin polymers by irradiating the polymer and treating it with a grafting monomer. In one example, polypropylene is irradiated with an electron beam with an energy of 2 MeV and subsequently treated with maleic anhydride as a grafting monomer.

[0023] US document 4,916,198 discloses the irradiation of polypropylene powder and the addition of additives after irradiation. The polypropylene granules and the use of linseed oil are not disclosed.

[0024] US patent 5,414,027 also describes electron beam irradiation of a propylene polymer, but not the use of linseed oil as a stabilizer.

[0025] US documents 2,948,666 and US documents 5,605,936 reveal Petition 870230098439, dated 07 / 11 / 2023, page 14 / 264 9 / 67 processes for the production of irradiated polypropylene. The latest descriptive report describes the production of a high molecular weight nonlinear propylene polymeric material, characterized by the high strength of the molten material by high-energy irradiation of a high molecular weight linear propylene polymer. It is revealed that the ionizing radiation for use in the irradiation step may comprise electrons irradiated from an electron generator with an acceleration potential of 500 to 4000 kV. For a propylene polymeric material without polymerized diene content, the ionizing radiation dose is 0.5 to 7 Mrad. For a propylene polymeric material with polymerized diene content, the dose is 0.2 to 2 Mrad.

[0026] Document EP 0 821 018 discloses the preparation of crosslinkable olefinic polymers that have been subjected to ionizing radiation. The descriptive report exemplifies relatively low-energy, low-dose electron beams to split polymer chains in order to graft silane derivatives onto the polymer chain. The descriptive report does not address the problem of achieving high melt strength of the polymers.

[0027] US patent 5,411,994 discloses the production of polyolefin graft copolymers in which a mass of olefinic polymer particles is irradiated and then the mass is treated with a vinyl monomer in liquid form. The ionizing radiation dose is about 1 to 12 Mrad and the ionizing radiation preferably comprises electrons emitted by an electron generator with an accelerating potential of 500 to 4000 kV. The polymer is first irradiated and then treated with a grafting agent. Petition 870230098439, dated 07 / 11 / 2023, p. 15 / 264 10 / 67

[0028] It is also known that when irradiating isotactic polypropylene, which was produced using conventional ZieglerNatta catalysts, irradiation of the polypropylene with an electron beam produces free macroradicals and there is a competition between chain scission and branching that is in favor of chain scission.

[0029] The use of branching agents, for example multivinyl compounds, to shift the equilibrium towards branching is known. For example, document CA 2 198 651 discloses that unsaturated bifunctional monomers can be added before and / or during irradiation. These compounds may include divinyl compounds, alkyl compounds, dienes or mixtures thereof. These unsaturated bifunctional monomers can be polymerized with the help of free radicals during irradiation. Butadiene is particularly preferred. Document CA 2 198 651 also discloses a continuous method for producing polypropylene blends with increased stress crack resistance and molten material strength, in which a low-energy electron beam accelerator with an energy of 150 to 300 keV at a radiation dose of 0.05 to 12 Mrads is employed.This process also has the disadvantage that the production rate of irradiated powder may be somewhat low for commercial acceptance. Furthermore, the polypropylene powder to be irradiated must be in the form of very fine particles. The use of propylene-diene copolymers, for example 1,5hexadiene, is also known. The use of this copolymer substantially complicates the polymerization procedure due to the incomplete conversion of the dienes and the corresponding odor. Petition 870230098439, dated 07 / 11 / 2023, page 16 / 264 11 / 67

[0030] Document WO 01 / 88001 discloses a process for preparing branched polypropylene by irradiation in the presence of crosslinking-promoting gases such as butadiene and acetylene.

[0031] US documents 7,019,044 and EP 1,297,031 disclose a process for preparing branched polypropylene by irradiation of a propylene copolymer with double bonds > 0.1 / 10,000 carbon atoms.

[0032] Documents EP 1 187 860 and EP 1 170 306 disclose a process similar to document EP 0 787 750 by irradiation with an electron beam having an acceleration voltage > 5 MeV in the presence of branching agents such as acrylates, diacrylates, butadiene and tetravinylsilane.

[0033] Documents US 7 935 740 and US 8 399 536 disclose a process for producing high-strength melt-material polypropylenes by irradiation of polypropylene pellets containing at least one non-phenolic antioxidant such as phosphite, HALS, benzofuranones, hindered amines, hydroxylamines and others.

[0034] Document WO 2018 / 028922 (Sabic) discloses a process for producing high-strength molten polypropylene by irradiating polypropylene pellets containing only vitamin E.

[0035] Several unsaturated branching agents have been revealed for polypropylene to achieve the necessary level of branching without gel formation at low doses. These substances are employed to stabilize the macroradicals formed by hydrogen abstraction from the polypropylene chain by high-energy irradiation to form a branched structure by combination. The Petition 870230098439, dated 07 / 11 / 2023, page 17 / 264 12 / 67 Typical sensitizers are highly reactive unsaturated chemical compounds, such as acrylates, di- and tri-acrylates, conjugated dienes such as butadiene, acetylene, or vinyl compounds such as tetravinylsilane or divinylbenzene.

[0036] The use of these branching (or grafting or sensitizing) agents typically leads to the disadvantage of unpleasant odor, increased cost, and an increased possibility of environmental problems, particularly toxicity, as a result of unreacted branching or grafting agent in the modified polypropylene. Another common problem with all these proposed substances is a potential migration of unreacted branching agent from within the polymer or foam produced from the polymer into the environment.

[0037] A general problem associated with foaming by extruding long-chain branched polypropylene is the change in viscosity and strength of the molten material caused by shear during extrusion. This viscosity change creates problems for the use of repelletized PP foam production waste in the foaming process as a second component. The different melt strengths and viscosities of recycled high-strength polypropylene from the molten material compared to virgin high-strength polypropylene resin from the molten material limit the maximum addition level to 20–30% by weight for the production of very low-density foams.

[0038] Preferably, all substances (branching agents and antioxidants) used in this polypropylene composition should be from a renewable source and should generally be recognized as safe (GRAS) or Petition 870230098439, dated 07 / 11 / 2023, page 18 / 264 13 / 67 approved as food grade for use in polypropylene compositions, since food packaging is one of the main applications for branched polypropylene.

[0039] The present invention aims to provide polypropylene resins with enhanced properties, in particular enhanced melt strength, which can be manufactured at a high production rate using a branching agent from a renewable source.

[0040] Consequently, the present invention is directed to a high-strength cast material polypropylene (HMS-PP), which has a branching index g' determined according to GPC below 0.9 and which comprises derivable units of i) propylene and ii) at least one polyunsaturated fatty acid. The present invention is further directed to a process for the preparation of a high-strength cast polypropylene (HMS-PP), comprising the steps of a) provide a linear propylene polymer (L-PP), b) blending said propylene polymer (L-PP) with a coupling agent (CA) comprising a polyunsaturated fatty acid and c) irradiate the mixture obtained in step b) by means of electron beam irradiation.

[0041] Furthermore, the present invention is directed to a high-strength cast material polypropylene (HMSPP) obtained from said process.

[0042] The present invention also relates to a foam comprising high-strength polypropylene of Petition 870230098439, dated 07 / 11 / 2023, page 19 / 264 14 / 67 cast material (HMS-PP) as described above.

[0043] The present invention is further directed to a composition (C), comprising at least 10.0% by weight, based on the overall weight of composition (C), of recycled high-strength melt-form polypropylene (r-HMS-PP), wherein high-strength melt-form polypropylene (HMS-PP), as described above, is recovered from a waste plastic material derived from post-consumer and / or industrial waste.

[0044] Finally, the present invention relates to an article comprising high-strength cast polypropylene (HMS-PP) as described above.

[0045] Preferred embodiments of the invention are described in the dependent claims.

[0046] The present invention is described in more detail below.

[0047] As indicated above, the present invention is directed to a high-strength cast material polypropylene (HMS-PP), which has a branching index g' determined according to GPC below 0.9 and which comprises derivable units of i) propylene and ii) at least one polyunsaturated fatty acid.

[0048] The branching index g' defines the degree of branching and correlates with the amount of branching in a polymer. Preferably, the high-strength polypropylene of the cast material according to the present invention has a branching index g' determined according to GPC less than or equal to 0.85, more preferably less than or equal to 0.80. Petition 870230098439, dated 07 / 11 / 2023, page 20 / 264 15 / 67

[0049] The branching index g' of the high-strength polypropylene of the cast material according to the present invention will normally be at least 0.10.

[0050] The invention is directed to a high-strength cast polypropylene (HMS-PP) comprising derivable units of a polyunsaturated fatty acid. Said high-strength cast polypropylene (HMS-PP) is prepared by irradiating a linear polypropylene precursor in the presence of a polyunsaturated fatty acid. The latter is preferably obtained from a natural source. Therefore, the present invention is characterized by a high-strength cast polypropylene (HMS-PP) being obtainable through the use of a renewable substance such as a vegetable oil comprising a high amount of polyunsaturated fatty acids and electron beam irradiation.

[0051] The inventors unexpectedly found that a high-strength cast material polypropylene (HMSPP) comprising derivatives of a polyunsaturated fatty acid is well suited for: - limit the change in MFR during the extrusion of linear polypropylene (fluff and pellets) with a fractional MFR; - To create long-chain, high-strength branching of additional molten polypropylene material by electron beam irradiation; - To limit the change in viscosity and strength of the molten material of long-chain branched polypropylene caused by shear during extrusion. As used in this document, the term "fatty acid" Petition 870230098439, dated 07 / 11 / 2023, page 21 / 264 16 / 67 polyunsaturated refers to a fatty acid comprising at least two carbon-carbon double bonds. Preferably, the high-strength cast material polypropylene (HMS-PP) of the invention comprises derivable units of a bifunctionally unsaturated fatty acid, that is, a polyunsaturated fatty acid comprising two carbon-carbon double bonds.

[0052] It is preferred that the high-strength cast polypropylene (HMS-PP) comprise at least 0.05% by weight, more preferably 0.05 to 2.0% by weight, even more preferably 0.1 to 1.0% by weight, as 0.25 to 0.5% by weight of derivative units of at least one polyunsaturated fatty acid based on the total weight of the high-strength cast polypropylene (HMSPP).

[0053] It is especially preferable that at least one polyunsaturated fatty acid, such as the bifunctionally unsaturated fatty acid, be linoleic acid and / or α-linolenic acid.

[0054] The presence of derivative units of α-linolenic acid and / or other polyunsaturated vegetable oils in high-strength cast polypropylene (HMSPP) can be detected by 1H-NMR spectroscopy. In particular, it is preferable that the ratio between x / (zw) be in the range of 0.25 to 2.0, where x is the 1H-NMR signal intensity (400 MHz, 1,2-tetrachloroethane-d2) from 5.55 to 5.27 ppm, z is the 1H-NMR signal intensity (400 MHz, 1,2-tetrachloroethane-d2) from 4.85 to 4.73 ppm and w is the 1H-NMR signal intensity (400 MHz, 1,2-tetrachloroethane-d2) from 4.73 to 4.66 ppm. Figure 1 shows a 1H-NMR spectrum (400 MHz, Petition 870230098439, dated 07 / 11 / 2023, page 22 / 264 17 / 67 1,2-tetrachloroethane-d2) of an inventive high-strength cast polypropylene (HMS-PP). As can be deduced from Table 3, the signal at 5.55 to 5.27 ppm can be attributed to derivable units of unsaturated acids such as α-linolenic acid (LSO), and the intensity x of said signal after irradiation of a linear polypropylene in the presence of an unsaturated acid increases with the amount of said unsaturated acid added to the linear polypropylene.

[0055] The high-strength cast polypropylene (HMS-PP) according to the present invention may comprise an organometallic stearate selected from magnesium stearate, aluminum stearate, sodium stearate, and calcium stearate and / or at least one inorganic hydrotalcite, such as, for example, DHT4A. It is preferable that the high-strength cast polypropylene (HMSPP) comprise calcium stearate.The amount of organometallic stearate and / or inorganic hydrotalcite, preferably calcium stearate, may vary between 100 ppm and 1000 ppm by weight, more preferably between 200 ppm and 800 ppm by weight, even more preferably between 400 ppm and 600 ppm by weight, based on the total weight of the high-strength polypropylene of the cast material (HMS-PP).

[0056] The high-strength cast polypropylene (HMS-PP) according to the invention may contain other additives (AD), for example, nucleating and clarifying agents, stabilizers, release agents, fillers, peroxides, plasticizers, antioxidants, lubricants, antistatic agents, vitamin E, scratch-resistant agents, high-performance fillers, pigments and / or dyes, impact modifiers, flame retardants. Petition 870230098439, dated 07 / 11 / 2023, page 23 / 264 18 / 67 flame retardants, blowing agents, acid scavengers, recycling additives, coupling agents, antimicrobials, antifogging agents, anti-adherents, antiblocking agents, polymer processing aids and the like. These additives are commercially available and are, for example, described in “Plastic Additives Handbook, 6th edition 2009” by Hans Zweifel (pages 1141 to 1190). Preferably, the additives (AD) are selected from the group consisting of flame retardants, fillers, pigments, impact modifiers, antioxidants such as vitamin E (α-tocopherol), nucleating agents, process stabilizers, anti-adherents or mixtures thereof.

[0057] In addition, the term “additives (AD)” according to the present invention also includes carrier materials, in particular, polymeric carrier materials.

[0058] Preferably, the high-strength cast polypropylene (HMS-PP) of the invention does not comprise (a) additional polymers other than high-strength cast polypropylene (HMS-PP) in an amount greater than 5.0% by weight, preferably in an amount greater than 3.0% by weight, more preferably in an amount greater than 2.0% by weight, based on the weight of the high-strength cast polypropylene (HMS-PP). Any polymer that is a carrier material for additives (AD) is not calculated by the amount of polymeric compounds as indicated in the present invention, but by the amount of the respective additive.

[0059] The polymeric carrier material of the additives (AD) is a carrier polymer to ensure distribution Petition 870230098439, dated 07 / 11 / 2023, page 24 / 264 19 / 67 uniform in the high-strength cast polypropylene (HMS-PP) of the invention. The polymeric carrier material is not limited to a specific polymer. The polymeric carrier material may be an ethylene homopolymer, an ethylene copolymer obtained from ethylene and an α-olefin comonomer, such as a C3 to C8 α-olefin comonomer, a propylene homopolymer, and / or a propylene copolymer obtained from propylene and an α-olefin comonomer, such as an ethylene and / or C4 to C8 α-olefin comonomer. Preferably, the polymeric carrier material does not contain styrene-derivable monomeric units or derivatives thereof.

[0060] A high-strength cast polypropylene is branched and therefore differs from a linear polypropylene in that the polypropylene backbone covers the side chains, whereas an unbranched polypropylene, i.e., a linear polypropylene, does not cover the side chains. The side chains have a significant impact on the rheology of polypropylene. Thus, linear polypropylenes and high-strength cast polypropylenes can be clearly distinguished by their flow behavior under stress.

[0061] The strength of the stable cast material can be defined as the ratio of the cast material strength measured by Rheotens according to ISO 16790:2005 at 200 °C, acceleration of 120 mm / s², determined in standard shear (die pressure, 3 MPa (30 bar)) and intensified shear (die pressure 20 MPa (200 bar)), being less than 1.3. Therefore, it is preferable that the ratio of the cast material strength F30 determined by Rheotens measurement at 200 °C, acceleration of 120 mm / s², determined Petition 870230098439, dated 07 / 11 / 2023, page 25 / 264 20 / 67 in standard shear (die pressure 3 MPa (30 bar)), and the enhanced shear strength of the F200 cast material at a die pressure of 20 MPa (200 bar) is less than 1.3.

[0062] In addition to or alternatively to the preceding paragraph, it is preferred that the high strength cast material polypropylene (HMS-PP) according to the present invention meets equation (I), more preferably equation (Ib), even more preferably equation (Ic), F30(HMSPP)-F200(HMSPP) F30(hmspp) < 0.15 (I) F3q(HMSPP)-F200(HMSPP)< F30(hmspp) - ' (Ia) F30(HMSPP)-F200(HMSPP) ---------:-------------< 0.1 (Ib) F30(hmspp) where [F30(HMSPP)] is the resistance of the molten material. F30 is the high-strength cast polypropylene (HMS-PP) strength determined according to ISO 16790:2005 at a die pressure of 3 MPa (30 bar), and [F200(HMSPP)] is the F200 high-strength cast polypropylene (HMS-PP) strength determined according to ISO 16790:2005 at a die pressure of 20 MPa (200 bar).

[0063] The melt strength of linear polypropylene has an exponential dependence on the melt flow rate, which makes comparisons of branched polypropylenes with different melt flow rates very difficult. The additional melt strength F30 (AMS) of a high-strength melt polypropylene can be calculated according to equation (II) AMS = MS(HMS-PP) LMS (II) Petition 870230098439, dated 07 / 11 / 2023, page 26 / 264 21 / 67 wherein AMS is the additional melt strength F30 (AMS) determined in accordance with ISO 16790:2005 compared with the melt strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2 (230 °C, 2.16 kg) determined in accordance with ISO 1133 as high-strength melt polypropylene (HMS-PP) in [cN], MS(HMS-PP) is the melt strength F30 of high-strength melt polypropylene (HMS-PP) determined in accordance with ISO 16790:2005 in [cN], LMS is the melt strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2 (230 °C, 2.16 kg) determined in accordance with ISO 1133 as high-strength melt polypropylene (HMS-PP) in [cN],and the melt strength F30 (LMS) of the corresponding linear polypropylene having the same melt flow rate as high-strength melt polypropylene (HMS-PP) and a polydispersity in the range of 3 to 5 is determined according to equation (III), LMS = 17.35MFR-0.994(III) where MFR is the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of high-strength molten polypropylene (HMS-PP).

[0064] It is preferable that the high-strength polypropylene of the inventive cast material (HMS-PP) have an additional cast material strength F30 (AMS), as defined above, greater than 2.0 cN (for coating grade), more preferably greater than 20 cN (for foaming grade) and an extensibility v30 greater than 240 mm. The use of the cast material strength Petition 870230098439, dated 07 / 11 / 2023, page 27 / 264 22 / 67 additional F30 (AMS), as a normalized melt flow rate, allows comparison between branched polypropylene (HMS-PP) products with different melt flow rates.

[0065] The crystallization temperature Tc of high-strength cast polypropylene (HMS-PP), as determined by DSC, is generally lower than the crystallization temperature Tc of the linear polypropylene precursor resin before irradiation. In particular, high-strength cast polypropylene (HMS-PP) has a crystallization temperature Tc determined according to DSC below 120 °C, more preferably below 115 °C.

[0066] Furthermore, it is preferable that the high-strength cast polypropylene (HMS-PP) be thermomechanically stable. Therefore, it is preferable that the high-strength cast polypropylene (HMSPP) have a melting temperature Tm determined according to DSC of at least 155 °C, more preferably in the range of 155 to 167 °C, even more preferably in the range of 157 to 163 °C, as in the range of 158 to 160 °C.

[0067] The high-strength cast polypropylene (HMS-PP) preferably has a shear storage modulus G' tested at a frequency of 0.1 rad / s in the range of 200 to 500 Pa, more preferably in the range of 250 to 450 Pa, and even more preferably in the range of 300 to 400 Pa. Furthermore, it is preferable that the crossover point where the shear storage modulus G' equals the shear loss modulus G'' of the inventive high-strength cast polypropylene (HMS-PP) determined by DMS at 200 °C is below Petition 870230098439, dated 07 / 11 / 2023, page 28 / 264 23 / 67 of 22,000 Pas, more preferably below 12,000 Pas, even more preferably below 10,000 Pas and / or a Gc crossover point below 100 rad / s, more preferably below 70 rad / s, even more preferably below 50 rad / s.

[0068] The ratio between the shear storage modulus G' and the shear loss modulus G'' determined by DMS at 200 °C at a frequency of 0.1 rad / s is preferably below 2.5, more preferably below 2.0, and even more preferably below 1.5.

[0069] High strength cast polypropylene (HMS-PP) preferably has a degree of shear thinning defined as the ratio of the complex viscosity η* at a frequency of 0.05 rad / s to the complex viscosity η* at a frequency of 285 rad / s greater than 30, more preferably greater than 40, wherein the complex viscosity is determined via DMS, wherein to determine the DMS spectrum, an ARES G2 rheometer was used at 200 °C measuring at frequencies of 0.01 rad / s to 300 rad / s, at a linear viscoelastic strain of 5%, using 0.5 mm thick plates produced in accordance with ISO 1872-2 (2007).

[0070] The hot xylene insoluble fraction (XHU), as determined by 5 h soxhlet extraction of high-strength molten polypropylene (HMS-PP), is preferably below 0.25% by weight.

[0071] In addition, it is preferable that the high-strength cast polypropylene (HMS-PP) have a strain hardening coefficient determined by measuring the extensional viscosity at a temperature of 170 °C at a strain elongation rate. Petition 870230098439, dated 07 / 11 / 2023, page 29 / 264 24 / 67 of 1.0 s measured at 2.75 s above 8.0, more preferably greater than or equal to 10.0. The strain hardening coefficient is an indicator of the strength of the cast material.

[0072] The present invention is further directed to a process for the preparation of a high-strength cast polypropylene (HMS-PP), comprising the steps of: a) provide a linear propylene polymer (L-PP), b) blending said propylene polymer (L-PP) with a coupling agent (CA) comprising a branched unsaturated fatty acid ester and c) irradiate the mixture obtained in step b) by means of electron beam irradiation.

[0073] According to step a) of the inventive process, a linear propylene polymer (L-PP) is provided as a precursor to high-strength cast polypropylene (HMS-PP).

[0074] The linear propylene polymer (L-PP) applied in the present invention can be a propylene homopolymer or a propylene copolymer. Polypropylene compositions consisting of a linear propylene homopolymer or a linear propylene copolymer are known. A linear propylene homopolymer is obtained by polymerizing propylene under suitable polymerization conditions. A linear propylene copolymer is obtained by copolymerizing propylene with one or more other olefins, preferably ethylene, under suitable polymerization conditions. The preparation of propylene homopolymers and copolymers is, for example, described in Moore, EP (996) Polypropylene Handbook. Polymerization, Characterization, Properties, Processing, Petition 870230098439, dated 07 / 11 / 2023, page 30 / 264 25 / 67 Applications, Hanser Publishers; New York.

[0075] Polypropylene, as used in this document, means a propylene homopolymer or a propylene copolymer with an α-olefin, for example, an α-olefin chosen from the group of α-olefins with 2 or 4 to 10 C atoms, for example, wherein the amount of α-olefin is less than 10% by weight based on the total propylene copolymer.

[0076] Polypropylene and a copolymer of propylene with an α-olefin can be produced by any known polymerization technique, as well as by any known polymerization catalyst system. Regarding techniques, reference can be made to paste, solution or gas phase polymerizations; regarding the catalyst system, reference can be made to Ziegler-Natta, metallocene or single-site catalyst systems.

[0077] According to a preferred embodiment of the present invention, the linear propylene polymer (L-PP) is a linear propylene homopolymer (H-PP).

[0078] The degree of branching of the linear propylene polymer (L-PP) is preferably low, the branching index g' is preferably at least 0.95, more preferably at least 0.96, even more preferably at least 0.98, as well as at least 0.99. It is especially preferred that the linear propylene polymer (L-PP) has a branching index g' of 1.00.

[0079] In addition to or as an alternative to the preceding paragraph, it is preferred that the amount of branching in the linear propylene polymer (L-PP) be low. In particular, it is preferred that the branching in the polymer be Petition 870230098439, dated 07 / 11 / 2023, page 31 / 264 26 / 67 linear propylene (L-PP) is in the range of 0 to 10 branches / 1000 carbon atoms, more preferably in the range of 0 to 5 branches / 1000 carbon atoms, even more preferably in the range of 1 to 5 branches / 1000 carbon atoms.

[0080] Preferably, the linear heterophasic polypropylene (L-PP) composition has a melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 in the range of 0.1 to 100 g / 10 min, more preferably in the range of 1.0 to 100 g / 10 min, even more preferably in the range of 1.0 to 25.0 g / 10 min, as in the range of 1.0 to 8.0 g / 10 min.

[0081] The linear propylene (L-PP) polymer may be a copolymer or a homopolymer of propylene, the latter being preferred. Furthermore, the linear propylene (LPP) polymer may comprise one or more different linear propylene (L-PP) polymer components.

[0082] If the linear propylene polymer (L-PP) is a propylene copolymer, it is preferable that the linear propylene polymer (L-PP) have a comonomer content in the range of 0.2 to 25.0 mol%, more preferably in the range of 0.5 to 20.0 mol%, even more preferably in the range of 2.0 to 15.0 mol%, as in the range of 6.0 to 12.0 mol%.

[0083] It is preferable that the comonomer be selected from ethylene and / or C4 to Cs α-olefins. It is especially preferred that the comonomer be ethylene. For linear propylene polymers (L-PP) comprising more than one, such as two different propylene polymer components that are propylene copolymers, it is preferred that all propylene polymer components contain the same comonomer, such as ethylene. Petition 870230098439, dated 07 / 11 / 2023, page 32 / 264 27 / 67

[0084] According to one embodiment of this invention, linear propylene polymer (L-PP) is a heterophasic propylene copolymer (HECO) comprising: i) a matrix (M) that is a propylene polymer ii) an elastomer (E) that is a copolymer comprising propylene and ethylene-derived units and / or C4 to Cs α-olefin.

[0085] In the present invention, the term “heterophasic” generally indicates that the elastomer is (finely) dispersed in the matrix. In other words, the elastomer forms inclusions in the matrix. Thus, the matrix contains (finely) dispersed inclusions that are not part of the matrix, and said inclusions contain the elastomer. The term “inclusion,” according to this invention, should preferably indicate that the matrix and the inclusion form different phases in the heterophasic polypropylene, said inclusions being, for example, visible by high-resolution microscopy, such as electron microscopy or scanning force microscopy.

[0086] It is understood that the linear propylene polymer (LPP) that is a heterophasic propylene copolymer (HECO) preferably has a fairly low total comonomer content, preferably an ethylene content.Therefore, it is preferable that the comonomer content of the heterophasic propylene copolymer (HECO) be in the range of 4.0 to 17.0 mol%, preferably in the range of 5.0 to 14.0 mol%, and more preferably in the range of 6.0 to 10.0 mol%.

[0087] Heterophasic propylene copolymers (HECOs) are generally characterized by a xylene cold-soluble fraction (XCS) and a xylene cold-insoluble fraction (XCI). For the purpose of the present application, the soluble fraction Petition 870230098439, dated 07 / 11 / 2023, page 33 / 264 Cold xylene 28 / 67 (XCS) of heterophasic propylene copolymers (HECO) is essentially identical to the elastomer of said heterophasic propylene copolymers (HECO).

[0088] Therefore, when referring to the intrinsic viscosity and ethylene content of the elastomer of heterophasic propylene copolymers (HECO), it means the intrinsic viscosity and ethylene content of the xylene cold-soluble fraction (XCS) of said heterophasic propylene copolymers (HECO).

[0089] Therefore, the matrix content (M), that is, the content of the cold xylene insoluble fraction (XCI), in the linear propylene polymer (L-PP) being a heterophasic propylene copolymer (HECO) is preferably in the range of 75.0 to 93.0% by weight, more preferably in the range of 77.0 to 91.0% by weight, as well as 78.0 to 89.0% by weight.

[0090] On the other hand, the elastomer (E), that is, the cold soluble fraction content in xylene (XCS), in the linear propylene polymer (L-PP) being a heterophasic propylene copolymer (HECO) is preferably in the range of 7.0 to 25.0% by weight, more preferably in the range of 9.0 to 23.0% by weight, as in the range of 11.0 to 22.0% by weight.

[0091] The first component of linear propylene polymer (L-PP) as a heterophasic propylene copolymer (HECO) is the matrix (M).

[0092] Polypropylenes suitable for use as a matrix (M) may include any type of isotactic or predominantly isotactic polypropylene homopolymer or random copolymer known in the art. Thus, the polypropylene may be a propylene homopolymer or an isotactic random copolymer of propylene with ethylene and / or Petition 870230098439, dated 07 / 11 / 2023, page 34 / 264 29 / 67 C4 to C8 alpha-olefins, such as 1-butene, 1-hexene or 1-octene, where the total comonomer content is in the range of 0.05 to 10% by weight.

[0093] Furthermore, and preferably, the polypropylene matrix (M) has a fairly high melt mass flow rate. Consequently, it is preferable that in the present invention the polypropylene matrix (M), i.e., the xylene cold insoluble fraction (XCI) of the linear propylene polymer (L-PP), has a melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO1133 in a range of 100 to 1500 g / 10 min, more preferably of 120 to 800 g / 10 min, or even more preferably 140 to 600 g / 10 min, as in the range of 150 to 500 g / 10 min.

[0094] Furthermore, the polypropylene matrix (M) can be multimodal or bimodal in view of the molecular weight.

[0095] The expression “multimodal” or “bimodal” used throughout the present invention refers to the polymer modality, that is, the shape of its molecular weight distribution curve, which is the graph of the molecular weight fraction as a function of its molecular weight, and / or the shape of its comonomer content distribution curve, which is the graph of the comonomer content as a function of the molecular weight of the polymer fractions.

[0096] The second component of linear propylene polymer (L-PP) as a heterophasic propylene copolymer (HECO) is the elastomer (E).

[0097] The elastomer (E) preferably comprises, consists of, derivative units of (i) propylene and (ii) Petition 870230098439, dated 07 / 11 / 2023, page 35 / 264 30 / 67 ethylene and / or at least one other C4 to C20 α-olefin, such as C4 to C10 α-olefin, more preferably derivative units of (i) propylene and (ii) ethylene and at least one other α-olefin selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. The elastomeric copolymer (E1) may additionally contain derivative units of a conjugated diene, such as butadiene, or a non-conjugated diene; however, it is preferable that the elastomeric copolymer consist of derivative units of (i) propylene and (ii) only ethylene and / or C4 to C20 α-olefins.Suitable non-conjugated dienes, if used, include linear and branched chain acyclic dienes such as 1,4-hexadiene, 1,5-hexadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene and the mixed isomers of dihydromyrcene and dihydroocimene and single-ring alicyclic dienes such as 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,5-cyclododecadiene, 4-vinylcyclohexene, 1-allyl-4-isopropylidenecyclohexane, 3-allylcyclopentene, 4-cyclohexene and 1-isopropenyl-4-(4-butenyl)cyclohexane. Bridged ring and multi-ring fused alicylic dienes are also suitable, including tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo(2,2,1)hepta-2,5-diene, 2-methylbicycloheptadiene and alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene, 5-isopropylidene-norbornene, 5-(4-cyclopentenyl)-2-norbornene; and 5-cyclohexylidene-2-norbornene.The preferred non-conjugated dienes are 5-ethylidene-2-norbornene, 1,4-hexadiene and dicyclopentadiene.

[0098] Consequently, the elastomer (E) comprises at. Petition 870230098439, dated 07 / 11 / 2023, page 36 / 264 31 / 67 less propylene and ethylene derivable units and may comprise other derivable units of an additional α-olefin as defined in the preceding paragraph. However, it is particularly preferred that the elastomer (E) comprise only propylene and ethylene derivable units and optionally a conjugated diene, such as butadiene, or a non-conjugated diene as defined in the preceding paragraph, such as 1,4-hexadiene. Thus, a monomeric polymer of non-conjugated ethylene propylene diene (EPDM) and / or an ethylene propylene rubber (EPR) as elastomer (E) is especially preferred, the latter being the most preferred.

[0099] Just like the matrix (M), the elastomer (E) can be unimodal or multimodal, such as bimodal. Regarding the definition of unimodal and multimodal, such as bimodal, the same is presented in the definition above.

[0100] In the present invention, the content of propylene derivative units in the elastomer (E) is equivalent to the detectable propylene content in the xylene cold-soluble fraction (XCS). Consequently, the detectable propylene in the xylene cold-soluble fraction (XCS) is in the range of 45.0 to 75.0% by weight, more preferably 40.0 to 70.0% by weight. Thus, in a specific embodiment, the elastomer (E), i.e., the xylene cold-soluble fraction (XCS), comprises 25.0 to 65.0% by weight, more preferably 30.0 to 60.0% by weight, ethylene derivative units. Preferably, the elastomer (E) is a monomeric polymer of diene not conjugated with ethylene propylene (EPDM) or an ethylene propylene rubber (EPR), the latter being especially preferred, with a propylene and / or ethylene content as per Petition 870230098439, dated 07 / 11 / 2023, page 37 / 264 32 / 67 defined in this paragraph.

[0101] Furthermore, it is preferable that the comonomer content, preferably the ethylene content, of the xylene cold-soluble fraction (XCS) of the linear propylene polymer (L-PP) which is a heterophasic propylene copolymer (HECO) be greater than or equal to 35.0 mol%, preferably in the range of 35.0 to 65.0 mol%, more preferably in the range of 45.0 to 60.0 mol%, even more preferably in the range of 50.0 to 56.0 mol%. The comonomers present in the xylene cold-soluble fraction (XCS) are those defined above for the elastomer (E). In a preferred embodiment, the comonomer is ethylene only.

[0102] A preferred additional requirement of the present invention is that the intrinsic viscosity (IV) of the xylene cold-soluble fraction (XCS) of the linear propylene polymer (L-PP) that is a heterophasic propylene copolymer (HECO) is quite low. Therefore, it is understood that the intrinsic viscosity of the xylene cold-soluble fraction (XCS) of the linear propylene polymer (L-PP) that is a heterophasic propylene copolymer (HECO) is less than 3.5 dl / g, more preferably not greater than 3.4 dl / g. Even more preferably, the intrinsic viscosity of the cold-soluble xylene fraction (XCS) of linear propylene polymer (L-PP), which is a heterophasic propylene copolymer (HECO), is in the range of 1.8 to 3.5 dl / g, more preferably in the range of 1.9 to 3.4 dl / g, such as 2.0 to 3.4 dl / g. Intrinsic viscosity is measured according to ISO 1628 in decalin at 135 °C.

[0103] Preferably, the propylene content of the linear propylene polymer (L-PP) is 85.0 to 96.0% by weight, more Petition 870230098439, dated 07 / 11 / 2023, page 38 / 264 33 / 67 preferably 88.0 to 94.0% by weight, based on the total weight of the linear propylene polymer (L-PP), more preferably based on the amount of the matrix (M) and the elastomeric copolymer (E) together, in the case where the linear propylene polymer (L-PP) is a heterophasic propylene copolymer (HECO) as defined above.

[0104] Linear propylene polymer (L-PP), which is a heterophasic propylene copolymer (HECO), can be produced by merging the matrix (M) and the elastomer (E). However, it is preferable that the heterophasic propylene copolymer (HECO) be produced in a sequential step process, using reactors in a serial configuration and operating under different reaction conditions. As a consequence, each fraction prepared in a specific reactor can have its own molecular weight distribution and / or comonomer content distribution.

[0105] It is preferable that linear propylene polymer (L-PP) be prepared in the presence of: (a) a Ziegler-Natta catalyst comprising compounds (TC) of a transition metal from IUPAC Group 4 to 6, a Group 2 metal compound (MC) and an internal donor (ID); (b) optionally a cocatalyst (Co) and (c) optionally an external donor (ED).

[0106] This Ziegler-Natta catalyst can be any stereospecific Ziegler-Natta catalyst for polymer polymerization, preferably capable of catalyzing the polymerization and copolymerization of propylene and optional comonomers at a pressure of 500 to 10,000 kPa, in particular 2,500 to 8,000 kPa, and at a Petition 870230098439, dated 07 / 11 / 2023, page 39 / 264 34 / 67 temperature from 40 to 110 °C, in particular, from 60 to 110 °C.

[0107] It is especially preferred that the linear propylene polymer (L-PP) be a propylene homopolymer.

[0108] According to the present invention, the expression “propylene homopolymer” refers to a polypropylene consisting substantially of, i.e., at least 99.0% by weight, more preferably at least 99.5% by weight, even more preferably at least 99.8% by weight, as of at least 99.9% by weight, propylene units. In another embodiment, only the propylene units are detectable, i.e., only units have been polymerized.

[0109] Preferably, the propylene polymer (PP), as the propylene homopolymer (H-PP), is isotactic. Consequently, it is preferable that the propylene polymer (PP), as the propylene homopolymer (H-PP), has a fairly high pentad concentration (mmmm%), i.e., more than 94.1%, more preferably more than 94.4%, as of more than 94.4 to 98.5%, with even greater preference, at least 94.7%, as in the range of 94.7 to 97.5%.

[0110] According to step b) of the inventive process, linear propylene polymer (L-PP) is blended with a coupling agent (CA) comprising a branched unsaturated fatty acid ester. The linear propylene polymer (L-PP) is preferably melt-blended, for example by dry blending or extrusion, with the coupling agent (CA).

[0111] The mixture obtained in step b) of the inventive process preferably comprises 0.01 to 5.0% by weight, more preferably 0.1 to 2.0% by weight, even more preferably 0.2 to 2.0% by weight, even more Petition 870230098439, dated 07 / 11 / 2023, page 40 / 264 35 / 67 preferably 0.2 to 1.5% by weight, as 0.3 to 0.8% by weight of the coupling agent (CA) comprising an unsaturated and branched fatty acid ester, based on the overall weight of the mixture obtained in step b).

[0112] Preferably, the coupling agent (CA) is a natural source of polyunsaturated fatty acids. In particular, it is preferable that the coupling agent (CA) be linseed oil. Preferably, the linseed oil is native linseed oil.

[0113] Linseed oil is distinguished by its unusually large amount of α-linolenic acid, which has a distinct reaction with atmospheric oxygen and therefore acts as a stabilizer / radical scavenger for polypropylene and offers the combination of the highest content of polyunsaturated fatty acids with the lowest level of saturating fatty acids available as commercial vegetable oils. The USFDA has granted Generally Recognized as Safe (GRAS) status to linseed oil with high α-linolenic content. Consequently, the high-strength cast material polypropylene (HMS-PP) according to the present invention is suitable for the production of food containers and food-related products.

[0114] It is preferable that the mixture obtained in step b) be free of peroxides and dienes.

[0115] According to step c) of the inventive process, the mixture obtained in step b) comprising linear propylene polymer (L-PP) and the coupling agent (CA) is irradiated by means of electron beam irradiation.

[0116] Preferably, the electron beam radiation dosage is in the range of 50 to 150 kGy, more Petition 870230098439, dated 07 / 11 / 2023, page 41 / 264 36 / 67 preferably in the range of 60 to 140 kGy, even more preferably in the range of 70 to 120 kGy, even more preferably in the range of 90 to 120 kGy.

[0117] The mixture obtained in step b) can be irradiated in an inert or non-inert environment.

[0118] It is possible, for example, to use a reduced oxygen environment, as described, for example, in US patent 8,399,536, wherein the active oxygen is at a set and maintained concentration of less than about 15% by volume, relative to the total volume of the reduced oxygen environment. In this process, the irradiated intermediate polypropylene resin is maintained in the reduced oxygen environment for a period of time sufficient for a significant amount of long-chain branching to form within the irradiated intermediate polypropylene resin, and the irradiated intermediate polypropylene resin is treated while the irradiated intermediate polypropylene resin is in the reduced oxygen environment to substantially deactivate all free radicals present in the irradiated intermediate polypropylene resin.

[0119] Irradiation of the mixture obtained in step b) is preferably carried out in an inert atmosphere. In particular, it is preferable that irradiation be carried out under nitrogen.

[0120] After irradiation step c), the mixture can be heated in order to deactivate the remaining radicals. In particular, it is preferable that the mixture obtained after step c) be heated to a temperature of 60 to 120 °C, more preferably 80 to 110 °C, even more preferably 90 to 100 °C. Petition 870230098439, dated 07 / 11 / 2023, page 42 / 264 37 / 67

[0121] Optionally, high-strength cast polypropylene (HMS-PP) is subsequently compounded with organometallic stearate and / or inorganic hydrotalcite and additives (AD) as defined above.

[0122] The present invention also relates to a mixture comprising high-strength cast material polypropylene (HMS-PP) as described above and one or more additional polymeric components. Preferably, said one or more additional polymeric components consist of one or more additional polyolefins. More preferably, said one or more additional polymeric components are selected from the group consisting of propylene homopolymers, propylene copolymers, polyethylene homopolymers and copolymers, and heterophasic propylene copolymers, as described above.

[0123] The present invention is further directed to a high-strength cast polypropylene (HMS-PP) obtained according to the process described above. With regard to the properties of the high-strength cast polypropylene (HMS-PP), reference is made to the definitions provided above.

[0124] The present invention also relates to a composition (C), comprising at least 10.0% by weight of recycled high-strength melt-form polypropylene (r-HMS-PP), wherein high-strength melt-form polypropylene (HMS-PP) as described above is recovered from a plastic waste derived from post-consumer and / or industrial scrap.

[0125] For the purposes of this description and subsequent claims, the term “polypropylene” Petition 870230098439, dated 07 / 11 / 2023, page 43 / 264 "38 / 67 recycled high-strength cast material (r-HMSPP)" is used to indicate a material recovered from both post-consumer waste and industrial waste, as opposed to virgin polymers. Post-consumer waste refers to objects that have completed at least one first use cycle (or life cycle), i.e., that have already served their first purpose; while industrial waste refers to manufacturing waste, which typically does not reach a consumer.

[0126] The term “virgin”, on the other hand, denotes newly produced high-strength melt-material polypropylene (HMS-PP) materials and / or objects prior to their first use, which have not yet been recycled. Virgin high-strength melt-material polypropylene (HMS-PP) may comprise additives that are added during or subsequent to the preparation process to increase storage stability, such as antioxidants and UV stabilizers.

[0127] Preferably, recycled high-strength melt-form polypropylene (r-HMS-PP) comprises other additives that are typically added before virgin high-strength melt-form polypropylene (r-HMS-PP) is further processed into the final article. Thus, it is preferable that recycled high-strength polypropylene from cast material (r-HMS-PP) comprise flame retardants, fillers, pigments, impact modifiers, antioxidants such as α-tocopherol, nucleating agents, process stabilizers, anti-adherent agents, or mixtures thereof.

[0128] Typically, high-strength polypropylene Petition 870230098439, dated 07 / 11 / 2023, page 44 / 264 39 / 67 of virgin melt-cast polypropylene (HMS-PP) is subsequently processed into an article that involves subjecting the high-strength melt-cast polypropylene (HMS-PP) to an extrusion process. Without being bound by theory, the shear forces acting during an extrusion process lead to an increase in the melt flow rate of the extruded polymer. Therefore, recycled high-strength melt-cast polypropylene (r-HMS-PP) that has been processed into an article by an extrusion process has a higher melt flow rate than the corresponding high-strength virgin melt-cast polypropylene (HMS-PP).

[0129] Therefore, it is preferable that the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of recycled high-strength polypropylene from the molten material (r-HMS-PP) be greater than the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of the original high-strength polypropylene from the molten material (o-HMS-PP).

[0130] The original term denotes newly produced high-strength polypropylene from cast material (o-HMS-PP) that has been used to produce materials contained in post-consumer waste and industrial waste, recycled high-strength polypropylene from cast material (r-HMS-PP) is obtained.

[0131] In particular, it is preferable that the MFR2 melt flow rates (230 °C, 2.16 kg) determined in accordance with ISO 1133 of recycled high-strength melt-material polypropylene (r-HMS-PP) and source high-strength melt-material polypropylene (o-HMS-PP) satisfy Petition 870230098439, dated 07 / 11 / 2023, p. 45 / 264 40 / 67 equation IV, more preferably equation IVa, even more preferably equation IVb: MFR2(oHMS^ < 5 (IV) MFR2(rHMSPP) mfr2(ohmsPP)< goMFR2(rHMSPP) “, mfr2(ohmsPP)<83 MFR2(rHMSPP) “' (Iva) (IVb) where MFR2(oHMSPP) is the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of the high-strength polypropylene molten material (o-HMS-PP) and MFR2(rHMSPP) are the melt flow rates MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of high-strength recycled polypropylene from melt-cast material (r-HMS-PP).

[0132] The present invention also relates to foamed objects or articles that are produced using high-strength cast polypropylene (HMS-PP) according to the present invention.

[0133] The present invention further relates to an article comprising high-strength cast polypropylene (HMS-PP) or composition (C) as described above. Preferably, the article comprises at least 80% by weight, more preferably at least 90% by weight, even more preferably at least 95% by weight, as at least 99% by weight of high-strength cast polypropylene (HMS-PP) or composition (C), based on the total weight of the article. It is especially preferred that the article consists of high-strength cast polypropylene (HMS-PP) or composition (C).

[0134] The article is preferably a foamed article, more preferably an extruded foam article, a Petition 870230098439, dated 07 / 11 / 2023, page 46 / 264 41 / 67 injection molded foam article or a pearlescent foam article, a blow-molded injection molded article or a blown film.

[0135] Preferably, the article is a foamed article, an injection blow-molded article, or a blown film. It is especially preferred that the article be a foamed article, such as an extruded foam article, an injection foam molded article, or a particle foam article.

[0136] High-strength cast polypropylene (HMS-PP) according to the invention can be formed into foam structures by a melt processing step. This melt processing step can be carried out in a melt extruder. A blowing agent can be added to the melt processing to induce foam cell formation. This blowing agent can be a chemical blowing agent or a physical blowing agent. The chemical blowing agent can, for example, be selected from sodium bicarbonate, citric acid derivatives, azodicarbonamide, hydrazodicarbonamide, 4,4'-oxybis(benzenesulfonyl hydrazide), N,N-dinitrosopentamethylenetetramine, 5-phenyltetrazole, p-toluenesulfonyl hydrazide and / or p-toluenesulfonylsemicarbazide. The physical blowing agent can, for example, be selected from nitrogen, carbon dioxide, isobutane, pentane and cyclopentane. Preferably, the blowing agent is isobutane.

[0137] The blowing agent can be introduced into the extruder at a location where the high-strength molten polypropylene (HMS-PP) is in accordance with Petition 870230098439, dated 07 / 11 / 2023, page 47 / 264 42 / 67 The invention is in a cast state. For example, it is preferable that the blowing agent be introduced in amounts in the range of 1.0 to 20.0% by weight, more preferably in the range of 1.5 to below 10.0% by weight, even more preferably in the range of 2.0 to 5.0% by weight, based on the total weight of the high-strength polypropylene (HMS-PP) of the cast material. The introduction of these amounts of blowing agent can contribute to the formation of a foamed structure that has a desired low density in combination with a desired high fraction of closed cells. It is preferable that 2.0 to below 10.0% by weight, more preferably more than 2.0 to 5.0% by weight of isobutene, based on the total weight of the high-strength polypropylene (HMS-PP) of the cast material, be used as the blowing agent.

[0138] In addition, other commonly known additives suitable for the production of foam structures from propylene-based polymer compositions may be used. For example, a quantity of a nucleating agent, such as talc and / or fatty acid (bis)amides, may be added. Preferably, talc is used as the nucleating agent. For example, it is preferable that the nucleating agent be added in amounts of 0.1 to 2.0% by weight, more preferably 0.5 to 1.5% by weight, based on the total weight of the high-strength polypropylene of the melt material (HMS-PP).

[0139] In addition, a quantity of a cell stabilizer, such as glycerol monostearate (GMS), glycerol monopalmitate (GMP), glycol distearate (GDS), palmitides and / or amides, for example, stearyl stearamide, palmitamide Petition 870230098439, dated 07 / 11 / 2023, page 48 / 264 43 / 67 and / or stearamide may be added. Preferably, glycerol monostearate is used as a cell stabilizer. For example, it is preferable that the cell stabilizer be added in amounts of 0.1 to 2.0% by weight, more preferably 0.5 to 1.5% by weight, based on the total weight of the high-strength polypropylene of the cast material (HMS-PP).

[0140] High-strength melt-material polypropylene (HMS-PP) can subsequently be extruded from a die outlet of the melt extruder. Thus, the foam structure can be formed. Different material properties of the propylene-based polymer composition according to the invention and of the foam structures produced using this composition were determined through the methods described in this document.

[0141] The present invention also relates to foam produced with high-strength cast polypropylene (HMS-PP) obtained by the irradiation process according to the invention.

[0142] The density of the foam structures is in the range between 20 and 800 kg / m3. The density of the foam structures was determined as the apparent bulk density according to ISO 845 (2006). The closed-cell fraction is preferably greater than or equal to 90%, more preferably greater than or equal to 98%, even more preferably greater than 98%. The closed-cell fraction was determined by placing a sample of foam with a known mass and a known density, determined as the apparent bulk density according to ISO 845 (2008), in a desiccator. Each sample was 5 cm long and 3 cm wide. The desiccator Petition 870230098439, dated 07 / 11 / 2023, page 49 / 264 44 / 67 was filled with water and polyethylene glycol as a surfactant. The pressure in the desiccator was reduced to 0.5 MPa (500 mbar). The samples were kept under these conditions for 0 min, after which the objects were subjected to a foaming process by extrusion of the molten material using a propylene-based composition produced according to the process of the invention, wherein the foamability window is greater than or equal to 5 °C, the foamability window being defined as the temperature range in which foams with an apparent total density less than or equal to 175 kg / m3 as determined in accordance with ISO 845 (2006) and a closed-cell content greater than or equal to 90% can be produced when using 2.3% by weight of isobutane as a blowing agent.

[0143] The invention also relates to a foamed object produced using a propylene-based composition produced according to the process of the present invention wherein the foamed object has an apparent overall density less than or equal to 300 kg / m3 as determined in accordance with ISO 845 (2006) and a closed-cell content greater than or equal to 90%.

[0144] The invention will now be illustrated by the following non-limiting examples. EXAMPLES A. Measurement methods

[0145] The following definitions of terms and methods of determination apply to the general description of the invention above, as well as to the examples below, unless defined otherwise.

[0146] MFR2 (230 °C) is measured according to ISO 1133 (230 °C, 2.16 kg load). Microstructure quantification by NMR spectroscopy Petition 870230098439, dated 07 / 11 / 2023, p. 50 / 264 45 / 67

[0147] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify comonomer content and comonomer sequence distribution of the polymers. Quantitative 13C{1H} NMR spectra were recorded in solution state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for 1H and 13C, respectively. All spectra were recorded using a 10 mm extended temperature probe head optimized for 13C at 125 °C using nitrogen gas for all pneumatics. Approximately 200 mg of material were dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) together with chromium(III)-acetylacetonate (Cr(acac)3) resulting in a 65 mM relaxing agent solution in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure a homogeneous solution, after preparing the initial sample in a heating block, the NMR tube was further heated in a rotary oven for at least 1 hour. Upon insertion into the magnet, the tube was rotated at 10 Hz. This configuration was chosen primarily for its high resolution and is quantitatively necessary for accurate quantification of ethylene content. Standard single-pulse excitation was employed without NOE, using an optimized tip angle, 1 s recycle delay, and a WALTZ16 dual-level decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) variables were acquired by Petition 870230098439, dated 07 / 11 / 2023, page 51 / 264 46 / 67 spectra.

[0148] Quantitative 13C{1H} NMR spectra were processed, integrated, and relevant quantitative properties determined from the integrals using specific computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using solvent chemical shift. This approach allowed comparable referencing even when this structural unit was not present. The characteristic signals corresponding to ethylene incorporation were observed in Cheng, HN, Macromolecules 17 (1984), 1950).

[0149] For polypropylene homopolymers, all chemical shifts are internally referenced to the isotactic methyl pentad (mmmm) at 21.85 ppm.

[0150] Characteristic signs corresponding to regiodefects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, H.N. Macromolecules 17 (1984), 1950) or comonomer were observed.

[0151] The tacticity distribution was quantified by integrating the methyl region between 23.6-19.7 ppm with correction for any sites unrelated to the stereo sequences of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30 (1997) 6251).

[0152] Specifically, the influence of regiodefects and Petition 870230098439, dated 07 / 11 / 2023, page 52 / 264 47 / 67 comonomer in the quantification of the tacticity distribution was corrected by subtracting representative regiodefect and comonomer integrals from the specific integral regions of the stereo sequences.

[0153] Isotacticity was determined at the pentad level and reported as the percentage of isotactic pentad sequences (mmmm) relative to all pentad sequences:

[0154] [mmmm] % = 100 * (mmmm / sum of all pentads)

[0155] The presence of 2,1 erythro regiodefects was indicated by the presence of the two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites.

[0156] The characteristic signs corresponding to other types of regiodefects were not observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0157] The amount of 2.1 erythro regiodefects was quantified using the integral mean of the two characteristic methyl sites at 17.7 and 17.2 ppm: P21e = ( Ie6 + Ie8 ) / 2

[0158] The amount of primary 1,2-propene inserted was quantified based on the methyl region with corrections made for sites included in that region not related to primary insertion and for primary insertion sites excluded from that region: P12 = ICH3 + P12e

[0159] The total amount of propene was quantified as the sum of primary propene inserted and all other regiodefects present: Ptotal = P12 + P21e

[0160] The mole percentage of 2,1 erythro regiodefects Petition 870230098439, dated 07 / 11 / 2023, page 53 / 264 48 / 67 was quantified in relation to all propene: [21e] % mol = 100 * (P21e / Ptotal)

[0161] For copolymers, the characteristic signals corresponding to the incorporation of ethylene were observed in Cheng, HN, Macromolecules 17 (1984), 1950).

[0162] With regiodefects also observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, HN, Macromolecules 17 (1984), 1950) correction was necessary for the influence of such defects on comonomer content.

[0163] The comonomer fraction was quantified using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) by integrating multiple signals across the entire spectral region in the 13C{1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regiodefects when necessary. The integral regions were slightly adjusted to increase applicability across the entire range of comonomer contents found.

[0164] For systems in which only isolated ethylene in PPEPP sequences was observed, the method of Wang et al. was modified to reduce the influence of non-zero integrals of sites that are known not to be present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reducing the number of sites used to determine the absolute ethylene content: E = 0.5(Spp + SPy + Sβδ + 0.5(S«p + Say))

[0165] Through the use of this set of sites, the equation Petition 870230098439, dated 07 / 11 / 2023, p. 54 / 264 The corresponding integral of 49 / 67 becomes: E = 0.5(Ih + Ig + 0.5(Ic + Id)) using the same notation used in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157). The equations used for absolute propylene content were not modified.

[0166] The molar percentage of comonomer incorporation was calculated from the molar fraction: E [% in mol] = 100 * fE The comonomer incorporation percentage by weight was calculated from the mole fraction: E [% by weight] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1-fE) * 42.08))

[0167] The comonomer sequence distribution at the triad level was determined using the analytical method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen for its robust nature and slightly adjusted integration regions to increase applicability to a wide range of comonomer content. Determination of the concentration of the grafted coupling agent (α-linolenic acid) after 1H-NMR irradiation 1. Soxhlet extraction to remove ungrafted coupling agent

[0168] 2.5 g of the ground sample are weighed into a sleeve Soxhlet extractor. In a round flask (250 ml), 200 ml of n-hexane are placed, and the sleeve is inserted into the Soxhlet. The extraction of the ungrafted coupling agent occurs under reflux cooling over a period of 24 hours. The residue is dried overnight in a vacuum drying oven at 90°C. Petition 870230098439, dated 07 / 11 / 2023, page 55 / 264 50 / 67 °C, cooled to room temperature and used by 1H-NMR spectroscopy method. 2. 1H-NMR spectroscopy method

[0169] Quantitative 1H NMR spectra recorded in solution state using a Bruker AVNEO 400 NMR spectrometer operating at 400.15 MHz. All spectra were recorded using an optimized 13C 10 mm extension selective excitation probe head at 125 °C with the use of nitrogen gas for all pneumatics. Approximately 200 mg of material were dissolved in approximately 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) using approximately 3 mg of Hostanox 03 (CAS 32509-66-3) as a stabilizer. Standard single-pulse excitation was employed using a 30-degree pulse, a relaxation delay of 3 s, and a sample rotation of 10 Hz. A total of 64k data points were collected by FID with a dwell time of 61 ps, corresponding to a spectral window of approximately 20 ppm. 512 transient elements were acquired by spectrograms using 4 simulated scans.This configuration was chosen for its high sensitivity, resolution, and stability with respect to unsaturated species.

[0170] Quantitative 1H spectra were processed by applying an exponential windowing function with 0.3 Hz line broadening, integrated and relevant proportions determined from the integral intensities. All chemical shifts were indirectly referenced to TMS at 0.00 ppm using the resulting signal from the residual protonated solvent at 5.95 ppm {Resconi L., Cavallo L., Fait A., Piemontesi F., Chem. Rev. 2000, 100, 1253} and the aliphatic mass signal intensity (Imass) defined as Petition 870230098439, dated 07 / 11 / 2023, page 56 / 264 51 / 67 100,000. Characteristic signals in specific 1H NMR chemical shifts corresponding to the presence of the listed structural groups were observed, which are summarized in Table 1 {Resconi L., Piemontesi F., Camurati I., Sudmeijer O., Nifantèf IE, Ivschenko PV, Kuzmina LG, J. Am. Soc. 1998, 120, 2308-2321}: Table 1: 1H-NMR signal characteristics Structural group Chemical shift 1H NMR [ppm] Aliphatic mass intensity 2.80 — (-0.5) y terminal vinylidene 4.73 - 4.66 w internal vinylidene 4.85 - 4.73 z vinylene 5.55 - 5.27 x allyl isobutenyl 5.08 - 4.85 v hostanox 7.00 - 6.81 h

[0171] Figure 1 shows a typical 1H-NMR spectrum of an inventive high-strength cast material polypropylene (HMS-PP).

[0172] Ratios between the intensities of specific groups were calculated to compensate for the influences of other groups: ratio between x / z = x / (zw) ratio between x / y = x / (y-(h / 4*42)) Melting point Tm, crystallization temperature Tc, and enthalpy of fusion Hm

[0173] The melting temperature, Tm, is determined by differential scanning calorimetry (DSC) according to Petition 870230098439, dated 07 / 11 / 2023, page 57 / 264 52 / 67 ISO 11357-3 with TA-Instrument 2920 Dual-Cell with RSC cooling apparatus and data station. A heating and cooling rate of 10 °C / min is applied in a heating / cooling / heating cycle between +23 and +210 °C. The crystallization temperature (Tc) is determined from the cooling stage, while the melting temperature (Tm) and enthalpy of fusion (Hm) are determined in the second heating stage. Strength of cast material F30 and F200 and extensibility of cast material V30 and V200

[0174] The test described in this document follows ISO 16790:2005. The stress hardening behavior is determined by the method as described in the article “Rheotens-Mastercurves and Drawability of Polymer Melts”, MH Wagner, Polymer Engineering and Science, Vol. 36, pages 925 to 935. The stress hardening behavior of polymers is analyzed by the Rheotens apparatus (product of Gottfert, Siemensstr.2, 74711 Buchen, Germany) in which a bead of molten material is elongated by extraction with a defined acceleration.

[0175] The Rheotens experiment simulates industrial extrusion and spinning processes. In principle, a molten material is pressed or extruded through a round die and the resulting strand is carried. The stress in the extrudate is recorded as a function of melt properties and measurement parameters (especially the ratio between exit velocity and transport, practically a measure for the extension rate). For the results presented below, the materials were extruded with a HAAKE Polylab laboratory extruder system and a gear pump. Petition 870230098439, dated 07 / 11 / 2023, page 58 / 264 53 / 67 with cylindrical die (L / D = 6.0 / 2.0 mm). To measure the strength of the F30 molten material and the extensibility of the V30 molten material, the pressure at the extruder outlet (= gear pump inlet) is adjusted to 3 MPa (30 bar), bypassing a portion of the extruded polymer. To measure the strength of the F200 molten material and the extensibility of the V200 molten material, the pressure at the extruder outlet (= gear pump inlet) is adjusted to 20 MPa (200 bar), bypassing a portion of the extruded polymer.

[0176] The gear pump was pre-set to a filament extrusion rate of 5 mm / s, and the melting temperature was set to 200 °C. The turning line length between the die and Rheotens wheels was 80 mm. At the start of the experiment, the Rheotens wheel intake speed was set to the speed of the extruded polymer filament (zero tensile force): Then, the experiment was started by slowly increasing the tensioning speed of the Rheotens wheels until the polymer filament broke. The wheel acceleration was small enough so that the tensile force could be measured under near-steady conditions. The acceleration of the extracted molten material bead is 120 mm / s². The Rheotens was operated in combination with the EXTENS PC program. This is a real-time data acquisition program that displays and stores the measured tensile force and extraction speed data.The endpoints of the Rheotens curve (force versus pulley rotation speed), where the polymer yarn breaks, are considered to be either the melt strength F30 and melt extensibility v30 values, or the melt strength F200 and extensibility v30 values. Petition 870230098439, dated 07 / 11 / 2023, page 59 / 264 54 / 67 casting material V200, respectively.

[0177] The additional molten material strength (AMS) is calculated according to equation (II) AMS = MS(HMS-PP) — LMS (II), wherein AMS is the additional molten material strength F30 (AMS) determined according to ISO 16790:2005 compared to the molten material strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 as high-strength molten material polypropylene (HMS-PP) in [cN], MS(HMS-PP) is the molten material strength F30 of high-strength molten material polypropylene (HMS-PP) determined according to ISO 16790:2005 in [cN], LMS is the molten material strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 as high-strength molten material polypropylene (HMS-PP) in [cN], °C, 2.16 kg) determined according to ISO 1133 as high-strength cast polypropylene (HMS-PP) in [cN],and the melt strength F30 (LMS) of the corresponding linear polypropylene having the same melt flow rate as high-strength melt polypropylene (HMS-PP) and a polydispersity in the range of 3 to 5 is determined according to equation (III), LMS = 17.35MFR- 0.994(III), where MFR is the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 of high-strength molten polypropylene (HMS-PP).

[0178] Equation (III) is the fitting function for the melt flow rate MFR2 (230 °C, 2.16 kg) determined according to ISO 1133 and molten material strength F30 as Petition 870230098439, dated 07 / 11 / 2023, page 60 / 264 55 / 67 defined above for commercial linear propylene homopolymers tested by Rheotens. The melt flow rates and molten material strength F30 of said commercial linear propylene homopolymers from Borealis are summarized in Table 2. Table 2: Strength of cast material F30 as a function of the melt flow rate Commercial linear PP MFR [g / 10 min] Melt strength F30 [cN] BA390 0.2 87 BE50 0.3 60 HA001 0.5 35 HA507 0.9 17 HB600TF 2.0 9 HC205TF 5.0 3.5 HD120MO 10.0 1.8 The branching index g'

[0179] The relative amount of branching is determined using the g' index of the branched polymer sample. The long-chain branching index (LCB) is defined as g' = [η]br / ίη]lin. It is well known that if the value of g' increases, the branching content decreases. [η] is the intrinsic viscosity at 160 °C in TCB of the polymer sample at a given molecular weight and is measured by an in-line viscosity and concentration detector. Intrinsic viscosities were measured as described in the Cirrus Multi-Offline SEC-Software Version 3.2 manual using the Solomon-Gatesman equation. Petition 870230098439, dated 07 / 11 / 2023, page 61 / 264 56 / 67

[0180] The required concentration of each elution slice is determined by an RI detector.

[0181] [η]lin is the intrinsic viscosity of a linear sample and [η]br is the viscosity of a branched sample of the same molecular weight and chemical composition. The numerical mean of g'n and the weight mean g'w are defined as: 'n = D?]far ,i [9]lin ,i Σα;

[0182] Where ai is dW / dlogM of fraction ie and Ai is the cumulative dW / dlogM of the polymer up to fraction i. The [η]lin of the linear reference (isotactic linear PP) over molecular weight was measured with an in-line viscosity detector. The following K and α values ​​were obtained (K = 30.68*10-3 and α = 0.681) from the linear reference in the molecular weight range of logM = 4.5-6.1. The [η]lin per slice molecular weight for the g' calculations was calculated following the following relationship [η]lin,i= K*Mi“. [η]br,i was measured for each specific sample by an in-line viscosity concentration detector.

[0183] gpcBR Index:

[0184] The gpcBR index is calculated using the following formula:

[0185] In which the Mw elution dispersion of the elution area of ​​the]itn [η ](volume) (LS15) is detector light )H ' MW(LS15)Mw,Un calculated angle of ra from the area of 15° and [η] (volume) of corresponding viscosity using the Cirrus Multi-Offline SEC-Software version 3.2 and the following approach. Petition 870230098439, dated 07 / 11 / 2023, page 62 / 264 57 / 67 MW(LS15) =KLS ·Area^LS15-det dn d^ ·AreaRI-det [^(volume) = KIV•^^r^ (dl / g~)

[0186] Where Kls is the light scattering constant at an angle of 15°, dn / dc is the increment of the refractive index calculated from the RI detector constant, Kiv is the viscometer detector constant, Spi is the specific viscosity in each chromatographic slice and C is the corresponding concentration in g / dl. Shear thinning index (SHI)

[0187] The characterization of molten polymers by dynamic shear measurements is in accordance with ISO 6721-1 and 6721-10 standards. Measurements were performed on an Anton Paar MCR501 rotational stress-controlled rheometer, equipped with a 25 mm parallel plate geometry. Measurements were performed on compression-molded plates using a nitrogen atmosphere and establishing a deformation within the linear viscoelastic regime. Oscillatory shear tests were performed at 200 °C applying a frequency range between 0.01 and 300 rad / s and defining a gap of 0.5 mm.

[0188] In a dynamic shear experiment, the probe is subjected to homogeneous deformation in a variable sinusoidal shear strain or shear stress (strain-controlled and stress-controlled modes, respectively). In a strain-controlled experiment, the probe is subjected to a sinusoidal strain that can be expressed by Y(t) = Y0 sin(ot) (1) Petition 870230098439, dated 07 / 11 / 2023, p. 63 / 264 58 / 67

[0189] If the applied deformation is within the linear viscoelastic regime, the resulting sinusoidal stress response can be given by σ(t) = σο sin(ωt +δ) (2) where σ0 and γο are the stress and strain amplitudes, respectively; ω is the angular frequency; δ is the phase change (loss angle between the applied deformation and the stress response); t is the time.

[0190] The results of dynamic tests are typically expressed by means of several different rheological functions, namely, the shear storage modulus G', the shear loss modulus, G”, the complex shear modulus, G*, the complex shear viscosity, η*, the dynamic shear viscosity, η', the out-of-phase component of the complex shear viscosity η” and the loss tangent, tan η which can be expressed as follows: G' = — cosδ [Pa] (3) Yo G = — sinδ [Pa] (4) o G* = G' + iG [Pa] (5) η * = η ' - ίη [Pa-s] (6) η' = — [Pa-s] (7) ω η'' = — [Pa-s] (8) ω

[0191] The determination of the so-called Index of Shear thinning, which correlates with MWD and is independent of Mw, is performed as described in equation 9. __^_^^^_____(x / y)Eta* at 285 rad / s

[0192] For example, SHI(o,o5 / 2285) is defined by the value Petition 870230098439, dated 07 / 11 / 2023, page 64 / 264 59 / 67 of the complex viscosity, in Pa.s, determined at a frequency of 0.05 rad / s, divided by the value of the complex viscosity, in Pa.s, determined at a frequency of 285 rad / s.

[0193] The values ​​of storage modulus (G'), loss modulus (G), complex modulus (G*) and complex viscosity (η*) were obtained as a function of frequency (ω).

[0194] Thus, for example, η*300rad / s (eta*300rad / s) is used as an abbreviation for the complex viscosity at a frequency of 285 rad / s and η*0.05rad / s (eta*0.05rad / s) is used as an abbreviation for the complex viscosity at a frequency of 0.05 rad / s.

[0195] The loss tangent tan(delta) is defined as the ratio between the loss modulus (G) and the storage modulus (G') at a given frequency. Thus, for example, tan0.05 is used as an abbreviation for the ratio between the loss modulus (G) and the storage modulus (G') at 0.05 rad / s, and tan300 is used as an abbreviation for the ratio between the loss modulus (G) and the storage modulus (G') at 300 rad / s.

[0196] The tan(0.05) / tan(300) elasticity balance is defined as the ratio between the loss tangent tan(0.05) and the loss tangent tan(300).

[0197] The polydispersity index, PI, is defined by equation 10. 105..... PI = G'{mcop) , ωcop = ω for (G' = G'') (10) where ωοορ is the crossover angular frequency, determined as the angular frequency for which the storage modulus, G', is equal to the loss modulus, G''.

[0198] The values ​​are determined by means of a single-point interpolation procedure, as defined Petition 870230098439, dated 07 / 11 / 2023, page 65 / 264 60 / 67 using the Rheoplus software. In situations where a specific G* value is not achieved experimentally, the value is determined through extrapolation, using the same procedure as before. In both cases (interpolation or extrapolation), the Rheoplus option "Interpolate y-values ​​to x-values ​​from parameter" and the logarithmic interpolation type were applied. References: [1] “Rheological characterization of polyethylene fractions, Heino, E.L., Lehtinen, A., Tanner J., Seppala, J., Neste Oy, Porvoo, Finlândia, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th (1992), 1, 360-362. [2] “The influence of molecular structure on some rheological properties of polyethylene”, Heino, E.L., Borealis Polymers Oy, Porvoo, Finlândia, Annual Transactions of the Nordic Rheology Society, 1995. [3] “Definition of terms relating to the non-ultimate mechanical properties of polymers”, Pure & Appl. Chem., Vol. 70, No 3, páginas 701-754, 1998.

[0199] The hot-insoluble fraction in xylene (XHU) is determined according to EN 579. Approximately 2.0 g of the polymer (mp) are weighed and placed in a metal mesh which is weighed, the total weight being represented by (mp+m). The polymer in the mesh is extracted in a Soxhlet apparatus with boiling xylene for 5 hours. The eluent is then replaced with fresh xylene and boiling continues for another hour. The mesh is then dried and weighed again (mXHU+m). The mass of hot-insoluble xylene (mxHu) obtained by the formula mxHu+mmm=mxHu is placed in relation to the weight of the polymer (mp). Petition 870230098439, dated 07 / 11 / 2023, page 66 / 264 61 / 67 to obtain the fraction of insolubles in xylene mxHu / mp. B. Examples

[0200] The inventive examples IE1 to IE7 and the comparative examples CE1, CE2 and CE2a were prepared as follows:

[0201] As a linear precursor, the linear polypropylene homopolymer HA001 from Borealis is used, which has an MFR of 0.6 g / 10 min (230 °C, 2.16 kg / cm2; ISO 1133), a melting point of 161 °C, a crystallization temperature of 116 °C, and an isotacticity of 97.3% (pentad concentration in 13C NMR) produced by a paste process using a Ziegler-Natta catalyst. The molten strength F30 of the stabilized powder is 35 cN.

[0202] The linseed oil was purchased from Lausitzer Olmühle Hoyerswerda GmbH and is cold-pressed linseed oil comprising 99 g of fat, 23 g of monounsaturated fatty acids, 60 g of polyunsaturated fatty acids, 15 g of saturated fatty acids and 0.22 g of protein per 100 ml.

[0203] Borealis HA001 propylene homopolymer fluff was pelletized in a Prism TSE 24MC under nitrogen with linseed oil in quantities as indicated in Table 4 (examples P0 to P4). The yield was 10 kg / h. Additives were dosed via premixing or direct dosing in the extruder. The extruder temperature was set between 20 °C and 240 °C. The pellets thus obtained were irradiated as follows: The E Beam irradiation process was carried out in three stages: Granular radiation with a dose of 80-110 kGy, 10 Petition 870230098439, dated 07 / 11 / 2023, page 67 / 264 62 / 67 MeV at 20 °C in an inert atmosphere, belt speed 50 mm / s, belt width 800 mm, height of the irradiated sample bed 50 mm. The irradiated granules were heated for 30 minutes at 60 °C in an inert atmosphere. Deactivation of free radicals by heating for 30 minutes at 100 °C in an inert atmosphere.

[0204] The concentration of the grafted coupling agent was determined by 1H-NMR spectroscopy as described above. The results are summarized in Table 3.

[0205] The properties of the inventive and comparative polypropylenes obtained are summarized in Table 4.

[0206] In addition, the following commercial polymers were used as comparative examples: CE3 is the commercial HMS-PP PF814 from LyondellBasell. CE4 is the commercial HMS-PP WB140HMS from Borealis.

[0207] As can be deduced from Table 4, the rheological properties of the high-strength cast polypropylene (HMS-PP) according to the present invention are comparable to the properties of the comparative examples CE3 and CE4, which are high-strength cast polypropylenes prepared with a peroxide as a radical source and butadiene as a coupling agent. Table 4 also shows that the ratio between the cast strength F30 and the cast strength F200 is stable for the inventive examples, indicating that the high-strength cast polypropylene of the invention can be re-extruded without deterioration of rheological properties. Furthermore, no nucleation effects occur, since the crystallization temperature Tc Petition 870230098439, dated 07 / 11 / 2023, page 68 / 264 63 / 67 remains at the same level compared to the linear precursor (HA001).

[0208] Examples IE2, IE5, IE6, and IE7 are all based on the same linear polypropylene homopolymer HA001, to which 0.5% by weight of the same coupling agent was added and irradiated with the same dose. However, the properties are slightly different. This deviation is normal behavior.

[0209] A highly desirable value for the F30 molten material strength of high-strength cast polypropylene (HMS-PP) is close to 30 cN or more, preferably at least 30 cN. The important fact is that all inventive embodiments achieve this objective even if there is some variation in properties, despite partially the same conditions mentioned above.

[0210] As indicated above, variation in properties is normal. After the irradiation step, the high-strength polypropylene molten material still contains some radicals. These radicals react further when the sample of high-strength polypropylene molten material is transported to the measurement step for a particular property, for example, MFR or molten material strength. In the examples disclosed in this document, care was taken to quickly transport the sample to the respective measurement step. However, it cannot be guaranteed that the same conditions will always be achieved with respect to time interval, temperature and coupling agent concentration. Small deviations in conditions can cause measurable differences in properties. Petition 870230098439, dated 07 / 11 / 2023, page 69 / 264 64 / 67

[0211] Inventive Examples IE8 to IE13 were prepared in the same manner as Inventive Examples IE1 to IE7, except for the coupling agent used. Table 5 indicates the type and quantity of coupling agent added and the corresponding results.

[0212] Walnut oil is Walnufól from Aromatika BV, Netherlands, containing 9.8% saturated fat by weight.

[0213] Tung oil is Allendo® from Bindulin Werk, no. CAS 8001-20-5.

[0214] Sunflower oil is Osolio from Spar containing 10% saturated fat by weight.

[0215] All three of these oils were purchased from regular supermarkets in Linz, Austria. Petition 870230098439, dated 07 / 11 / 2023, page 70 / 264 65 / 67 Table 3: Determination of the concentration of the grafted coupling agent (linolenic acid) by XH-NMR. ratio between x / y - x / (y(h / 4*42)) 1__00+300Ό 1.61E-01 3.56E-04 10-338'1 go-366'ς LD H 3.00E-05 mi CO 8.07E-05 90-361'9 5.51E-05 4.68E-05 un W CO ratio between x / z = 44.33 53, 29 48.16 42.16 81'11 47.56 6Ê '05 55.45 3 aLyl isobutenyl 5.08 - 4.85 > o 0.00 0.00 0.00 00'0 GO 13.75 10.38 Ei '01 OJ 12.22 13.30 ΟΊ CO CM vinylene Ln CX] O 16100.00 35.36 18.09 96 '9 3, 72 2.98 8.33 8.03 5.76 CD 4.65 kD internal vinylidene 1 m GO k N °'67 1 00 '0 °'67 1 1.06 17, 43 15, 95 13.53 14.22 16.32 16. 39 17.92 17. 40 Terminal vinylidene s 1 CO 3 CD 0.00 1 I o CO 2.79 0.48 0.70 ^10 1.00 1 1.16 Aliphatic mass 2.80 - (-0,5) >1 OOG 000001 100000 100000 100000 000001 100000 100000 100000 100000 100000 100000 000001 structural group [uidd] nwm Ητ οοτιιιτηΕι material intensity | HA001 LSO cu CU £ HA001 irradiated CE3 | Irradiated PI Insoluble irradiated PI | P2 irradiated | Insoluble irradiated P2 | P3 irradiated | Insoluble irradiated P3, Petition 870230098439, dated 07 / 11 / 2023, p. 71 / 264 66 / 67 Table 4: Properties of inventive and comparative examples [Do] 113 116 113 115 115 t—1 113 112 1 711 114 113 113 113 125 129 160 [%] tie cc 25% 20% opypurij op 31·7 6 'f£ 34.6 CO [NO] SWW 17.4 37.1 7ΐ 27.5 30.5 9 '££ o 28.0 a ΐ9' LZ opTpunj,80 Op L701 PTOUS on CM LD on 35, 0 36, 0 s / pea τ'ο e pueq 07 9 '1 2·3 1'3 O co co 2.1 CN a·1 CO 'S' [e-ea] 982 EPS 154.9 118.0 LO 121.6 200.0 160.0 [S-Ed] 90'0 4257 6262.4 4223 w on m on □n □n 7890.2 S Ch <0 0008 m 00001 [τ-ee] Id 17 IC 8 cc cÜ 11.6 12,5 r^a^t ] □3 ο^υθίΗΕΖΠΣϋ θρ CQUOJ 20675 8624 11991 16582 11056 ££911 12686 198503 1 [s / pe^] οιυθπίΡζητΩ Θρ O^UOJ 126 Pi 6 '£6 163 CM L '99 713 CO on [-] 982 / 90'0 V13 IHS 27.5 53, 14 1 o '6 3 38.7 26.5 cc <0 40.0 62.5 [using οΐ / β] M3PÍ O tN Ή cm CN 11.3 CM cc mo on to on 5.0 11.2 CO 2.5 2.0 LOS9d UI3 ©05 'ETJC20,UI^ 0.05 LO m 0.25 0,1 in □n LD O C3 o CC [ÁOH] ason O o OO o O CO 011 110 110 oil 110 110 s CO 110 Ό C o ayduiexa OOO íú EU 04 CM m cu Eu IE1 231 IE3 IE4 1 1 IE5 IE6 | IE7 CE1 CE2 | CE2a CE3 CE4, Petition 870230098439, dated 07 / 11 / 2023, page 72 / 264 67 / 67 Table 5: Properties of inventive and comparative examples <0 —1 -H £ ,—1 to eH £ in CM Ό cpcc in CM cn CM c—1 cn ip —1 lp —1 2 cn ip r—1 ip e—1 kD 1------1 LT> lO l------1 CO in ç—1 a> in aocc<n in s e—1 í—1 £ ί—1 φ r-l 0*> Of CM [M2] OOZjj or pETjepem Op m 15 CM Τ m with m *M with O cn [No] OÍJ SKM £ 15 kp CM CM CD l—1 MS CO CM CtP] 15 ms / page VO^ ρυερ cm kO í—1 ί—1 i—l CM 1—1 M> 1—1 1—1 1 CM ΓΜ i—l [s-Ed] 587 SIS mm .—1 CÜ 00 m <—| 1—I σι m CM OO in 121.6 | 200.0 | oa 15 <—| fs'eaj GO'O »53 tM 9313.4 | IJ CO ç—1 u> CM in CM rM 1—1 CD m CO i—| in CM 1—1 [ Sdx 2 pg cquewznjo ep occuçj ΟΊ 05 kO σι 05 kD 3847.9 s 3472.5 w i— in CO σ i CM IP m [s / page] opuauuiPznjD ap opuo^ CM í—1 ç—1 CM r-| m C CO 05 CD σι 1—1 CM ι-l if ; / so'o vis ihs OT CO m r- m CM CO CM σι co σι in in CD co ip c 55 [used ον6] TidH MD O 1—1 CM N m ΤΓ Λ i—l CH co O in Q CM i—lw CM i—lw CM] ©qusÉy α O CM í—1 α in O lD CM in CM CM s tn CM in CM α o I Ό G c OlUOWldODE Sp 1 1 Flaxseed oil Flaxseed oil Flaxseed oil | Walnut oil| Tungue Oil Sunflower Oil | Walnut Oil | Tungue oil Sunflower oil 1 I Iá^i that O ooool—1 —| r-· —1 £ 05 s S CO OG a □ iduiexa ooso FH Pt CM FM 1*1 FM FM CG M CO a H σ, Μ Ι-Ι ou H u H CM H uau CM ω ri CM U;

Claims

1. High-strength cast polypropylene (HMSPP) characterized by having a branching index g' determined by GPC below 0.9, wherein the high-strength cast polypropylene (HMS-PP) satisfies equation (I) F0(HMSPP) - F200(HMSPP') F30(HMSPP) < 0.15 (I) wherein [F30(HMSPP)] is the F30 cast strength of high-strength cast polypropylene (HMS-PP), determined according to ISO 16790:2005 at 3 MPa (30 bar), and [F200(HMSPP)] is the F200 cast strength of high-strength cast polypropylene (HMS-PP), determined according to ISO 16790:2005 at 20 MPa (200 bar), the melting temperature is 200 °C and the acceleration is of 120 m / s2, wherein the high-strength cast polypropylene (HMSPP) comprises derivable units of: i) propylene and ii) at least one polyunsaturated fatty acid, wherein the high-strength cast polypropylene (HMS-PP) comprises 0.05 to 2,0% by weight of derivable units of at least one polyunsaturated fatty acid based on the total weight of the high-strength polypropylene cast material (HMS-PP), and at least one polyunsaturated fatty acid is linoleic acid and / or α-linolenic acid.

2. High-strength cast material polypropylene (HMSPP), according to claim 1, characterized by the fact that Petition 870260036779, dated 20 / 04 / 2026, page. 17 / 27 2 / 5 that the ratio between x / (zw) is in the range of 0.25 to 2.0, where x is the intensity of the 1H-NMR signal (400 MHz, 1,2-tetrachloroethane-d2) from 5.55 to 5.27 ppm, z is the intensity of the 1H-NMR signal (400 MHz, 1,2-tetrachloroethane-d2) from 4.85 to 4.73 ppm and w is the intensity of the 1H-NMR signal (400 MHz, 1,2-tetrachloroethane-d2) from 4.73 to 4.66 ppm.

3. High-strength cast polypropylene (HMS-PP), according to any one of claims 1 to 5, characterized in that the high-strength cast polypropylene (HMS-PP) has an additional cast strength F30 (AMS), determined according to ISO 16790:2005, compared with the cast strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2 determined at 230 °C and a load of 2.16 kg according to ISO 1133, as the high-strength cast polypropylene (HMS-PP), above 2.0 cN, wherein the additional cast strength F30 (AMS) is determined according to equation (II) AMS = MS(HMS-PP) — LMS (II), wherein AMS is the additional cast strength F30 (AMS), determined according to ISO 16790:2005, compared with the melt strength F30 (LMS) of a linear polypropylene with the same melt flow rate MFR2,determined at 230 °C to a load of 2.16 kg according to ISO 1133, as high-strength cast polypropylene (HMS-PP) in [cN], MS(HMS-PP) is the F30 cast strength of high-strength cast polypropylene (HMS-PP), determined according to ISO 16790:2005 in [cN], LMS is the F30 cast strength (LMS) of a linear polypropylene with the same melt flow rate MFR2, determined at 230 Petition 870260036779, dated 20 / 04 / 2026, page. 18 / 27 3 / 5 °C at a load of 2.16 kg according to ISO 1133, as high-strength molten polypropylene (HMS-PP) in [cN], and wherein the molten strength F30 (LMS) is determined according to equation (III) LMS = 17.35MFR - 0.994 (III), wherein MFR is the melt flow rate MFR2, determined at 230 °C with a load of 2.16 kg according to ISO 1133, of high-strength molten polypropylene (HMS-PP),wherein the shear strength of the cast material (HMS-PP) F30 is determined in accordance with ISO 16790:2005 at 30 bar, a melting temperature of 200 °C and an acceleration of 120 m / s².

4. High-strength cast polypropylene (HMSPP), according to any one of claims 1 to 3, characterized in that a crystallization temperature Tc determined according to DSC is below 120 °C.

5. Process for the preparation of a high-strength cast polypropylene (HMS-PP) characterized by comprising the steps of: a) providing a linear propylene polymer (L-PP), preferably a linear propylene homopolymer (H-PP), b) blending said propylene polymer (L-PP) with a coupling agent (CA) comprising a polyunsaturated fatty acid, and c) irradiating the mixture obtained in step b) by means of electron beam irradiation, wherein the mixture obtained in step b) comprises 0.1 to 2.0% by weight of the coupling agent (CA) comprising a polyunsaturated fatty acid, based on the total weight of the mixture obtained in step b), and Petition 870260036779, dated 20 / 04 / 2026, page 19 / 27 4 / 5 the coupling agent (CA) comprising a polyunsaturated fatty acid is native linseed oil.

6. Process according to claim 5, characterized in that the radiation dosage of the electron beam according to step c) is in the range of 50 to 150 kGy.

7. Composition (C) characterized by comprising at least 10.0% by weight, based on the total weight of composition (C), of recycled high-strength melt-material polypropylene (r-HMS-PP), being high-strength melt-material polypropylene (HMS-PP) as defined in any of claims 1 to 4, which is recovered from a residual plastic material derived from post-consumer and / or industrial waste.

8. Composition (C), according to claim 7, characterized in that the melt flow rates MFR2, determined at 230 °C at a charge of 2.16 kg according to ISO 1133, of recycled high-strength polypropylene from the molten material (r-HMS-PP) and of original high-strength polypropylene from the molten material (o-HMS-PP), being the high-strength polypropylene from the molten material, the recycled high-strength polypropylene from the molten material (r-HMS-PP) is obtained, satisfying equation IV: ^2(^^ < 0.95 IV, MF R2(rHMSPP) “ ' , wherein MFR2(oHMSPP) is the melt flow rate MFR2, determined at 230 °C at a charge of 2.16 kg according to ISO 1133, of original high-strength polypropylene from the molten material (o-HMS-PP) and MFR2(rHMSPP) is the melt flow rate MFR2, determined at 230 °C with a 2.16 kg charge according to ISO 1133, of recycled high-strength polypropylene molten material (r-HMS-PP). Petition 870260036779, dated 20 / 04 / 2026, p.20 / 27 5 / 5.

9. Composition (C), according to claim 7 or 8, characterized in that it comprises additives (AD) selected from the group consisting of flame retardants, fillers, pigments, impact modifiers, antioxidants, nucleating agent, process stabilizers, anti-adherents or mixtures thereof.

10. Article characterized by comprising high-strength cast polypropylene (HMS-PP) as defined in any one of claims 1 to 4 or composition (C) as defined in any one of claims 7 to 9.

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