Recycled polyethylene composition with good thermo-optical stability

Abstract

The present invention relates to a hybrid plastic recovery polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190 DEG C) of from 0.1 to 1.2 g / 10 min; a recycled low density polyethylene fraction (A) having a density of 930 to 955 kg / m3, and comprising 35 wt% or more of a recycled low density polyethylene fraction (A) having a crystallization temperature of not less than 106 DEG C; at least one HALS UV stabilizer; at least one metal deactivator; the first native high density polyethylene component (B) and, optionally, the second native high density polyethylene component (C) are blended with carbon black or other pigments wherein the hybrid plastic recovery polyethylene composition has a tensile strain at break of at least 500%, which tensile strain at break after a weather aging according to EN ISO 4892-2 for 2000 hours, and the tensile strain at break after a weather aging according to EN ISO 4892-2 for 2000 hours. And determining on a compression molding ISO 527-2 / 5A sample according to ISO 527-1. The invention also relates to a process for the preparation of such a hybrid plastic recycled polyethylene composition, articles made from such a hybrid plastic recycled polyethylene composition, especially sheath materials for power cables, and the use of such a hybrid plastic recycled polyethylene composition in wire and cable applications.

Description

Technical Field

[0001] The present invention relates to a mixed plastic recycled polyethylene composition with excellent thermal and light stability, a preparation method thereof, products made therefrom and use thereof in wire and cable applications. Background Art

[0002] Polyolefins, particularly polyethylene and polypropylene, are used in large and growing quantities in a variety of applications, including packaging for food and other goods, fibers, automotive parts, wire and cable, and a wide variety of manufactured goods.

[0003] Considering the huge amount of waste collected compared to the amount recycled into logistics, there is still a lot of potential for the smart reuse of plastic waste streams and the mechanical recycling of plastic waste.

[0004] Typically, a large amount of polyethylene recycled in the market is a mixture of polypropylene (PP) and polyethylene (PE), especially for post-consumer waste streams. In addition, commercial recyclates from post-consumer waste sources (PCR) are often cross-contaminated with non-polyolefin materials such as polyethylene terephthalate, polyamide, polystyrene, or non-polymeric substances such as wood, paper, glass, or aluminum. This cross-contamination significantly limits the end application or recycling stream, making the end use unprofitable.

[0005] In addition, unless the amount of recycled polyolefin added to the final compound is extremely low, the performance of the recycled polyolefin material is generally much worse than that of the virgin material. For example, such materials generally have limited impact strength and poor mechanical properties (such as brittleness), so they cannot meet customer requirements. This is particularly applicable to applications such as sheathing materials (for cables), containers, automotive parts or household items. This generally excludes the use of recycled materials in high-quality components and means that they are only used in low-cost, undemanding applications, such as construction or furniture. In order to improve the mechanical properties of these recycled materials, relatively large amounts of compatibilizers / coupling agents and elastomeric polymers are generally added. These materials are generally virgin materials produced from petroleum.

[0006] Another particular issue with recycled polyolefins (e.g., polyethylene) is that variations in ESCR (Environmental Stress Crack Resistance) can also be observed in recycled polyethylene blends, depending on the waste source. Therefore, these limitations need to be addressed in a flexible manner. For jacketing applications, an ESCR (Bell Test Time to Failure) greater than 1000 hours is often required.

[0007] Therefore, there remains a pressing need in the art to provide recycled polyethylene solutions for wire and cable applications, particularly wire and cable applications with acceptable and consistent mechanical properties that are similar to virgin polyethylene blends sold in the wire and cable application market. It is also desirable to maximize the amount of recycled polyethylene material.

[0008] Recycled polymers are contaminated with organic and inorganic substances. These contaminants can reduce or eliminate the effectiveness of certain additives added to the compositions containing the recyclate to enhance performance. For example, unwanted polyolefins, other polymers, and unwanted metals and functional groups can be introduced during the recycling process. Specifically, it has been reported in the literature that metals such as Co, Fe, Cu, Mo, Ti, and Zn can reduce thermal and light stability (e.g., Journal of Vinyl and Additive Technology 17, 21-27, (2011); Polymer Degradation and Stability 53, 79-87, (1996); Polymer Degradation and Stability 84, 7-11, (2004)).

[0009] Polyolefin recycling compositions are known to contain a stabilizer package comprising phenolic and phosphorus antioxidants, calcium stearate, HALS and a metal deactivator. The presence of the metal deactivator was found to significantly improve heat and light stability.

[0010] For example, EP 0 565 868 A2 discloses a polyolefin composition having improved oxidative stability, wherein the stable composition comprises an ethylene homopolymer or copolymer containing (a) a hindered phenol compound containing a divalent metal and (b) a metal deactivator having one or more hindered phenol groups linked to a hydrazine group or an oxalamide group. The stable polyolefin composition can be used for insulation of wires and cables and has enhanced oxidation resistance.

[0011] WO 2000 / 058975 A1 discloses a stable cable construction comprising (i) a plurality of insulated electrical conductors with gaps therebetween, the insulation comprising (a) one or more polyolefins, (b) one or more primary antioxidants, (c) one or more metal deactivators selected from alkylhydroxyphenylalkanoylhydrazines, (ii) a hydrocarbon cable filler grease in the gaps, and (iii) a jacket surrounding components (i) and (ii). The stable cable construction provides oxidative stability to polyolefin wire insulation, such as telecommunications cables.

[0012] CN 112745547 A discloses a recycled polyethylene material resistant to heat and oxygen aging, comprising recycled high-density polyethylene, recycled low-density polyethylene, a carbon black masterbatch, a compatibilizer, a first lubricant, and a composite antioxidant masterbatch. The composite antioxidant masterbatch comprises polyethylene, an antioxidant, a metal deactivator (N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine), a nucleating agent, and a second lubricant.

[0013] Recyclates contain a wide variety of metals in various oxidation states, compounds, and mineral forms. Their impact on polymer degradation is complex and rarely studied. These metal contaminants can further affect or degrade other additives in the recyclate, rendering them less effective or inactive.

[0014] It is therefore an object of the present invention to provide an improved recycled polyethylene composition having excellent thermo-photostability, weatherability and flame retardancy even in the presence of metal contamination. Summary of the Invention

[0015] Therefore, the present inventors have discovered a novel mixed plastic recycled polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.1 to 1.2 g / 10 min; a density of 930 to 955 kg / m 3 , and contains

[0016] More than 50% by weight of the recovered low-density polyethylene fraction (A) has a crystallization temperature of not less than 106°C;

[0017] At least one HALS UV stabilizer;

[0018] at least one metal deactivator;

[0019] wherein the mixed plastic recycled polyethylene composition has a tensile strain at break of at least 500% after 2000 hours of weathering according to EN ISO 4892-2 and as described in the experimental section below, measured according to ISO 527-1 on compression molded ISO 527-2 / 5A specimens.

[0020] The mixed plastic recycled polyethylene composition according to the present invention comprises a first virgin high-density polyethylene component (B) and an optional second virgin high-density polyethylene component (C), optionally blended with carbon black or other pigments, such as inorganic pigments and organic pigments, the inorganic pigments including iron oxide, titanium dioxide, zinc iron yellow, bismuth vanadate, mixed metal oxides, etc., and the organic pigments including quinacridone, benzimidazolone, isoindolinone, perylene, Cu-phthalocyanine, etc. The above objects can also be achieved by the preparation method of the above mixed plastic recycled polyethylene composition of the present invention, the method comprising the following steps: melt mixing and extruding the recycled polyethylene fraction (A) in an extruder in the presence of at least one HALS UV stabilizer and at least one metal deactivator and in the presence of the first virgin high-density polyethylene component (B) and / or the second virgin high-density polyethylene component (C).

[0021] The above objects can also be achieved by an article made from the mixed plastic recycled polyethylene composition according to the present invention, wherein the mixed plastic recycled polyethylene composition accounts for at least 85% by weight of the total composition used to make the article. The article is preferably a sheathing material for a power cable.

[0022] The above objects can also be achieved by using the mixed plastic recycled polyethylene composition according to the present invention in wire and cable applications. DETAILED DESCRIPTION

[0023] For the purposes of this specification and subsequent claims, the term "recycled waste" is used to denote materials recovered from post-consumer waste, rather than virgin polymers and / or materials. Post-consumer waste refers to objects that have completed at least their first use cycle (or life cycle), i.e., have completed their first purpose.

[0024] The term "virgin" refers to newly produced polymeric materials and / or objects prior to first use, which have not yet been recycled. The term "recycled material" as used herein refers to material that has been reprocessed from "recycled waste."

[0025] In the context of the present invention, the term "natural" means that the component has a natural color. This means that the component does not contain any pigments (including carbon black) in its composition.

[0026] Blend refers to a mixture of two or more components, wherein at least one component is a polymer. Generally, a blend can be prepared by mixing two or more components. Suitable mixing procedures are known in the art. The original high density polyethylene component (B) and / or (C) can be a high density polyethylene material made by a reactor. The high density polyethylene material can contain carbon black or any other pigment. However, carbon black or any other pigment may not exist. The original high density polyethylene material is a virgin material that has not been recycled.

[0027] Mixed plastic recycled polyethylene composition

[0028] For the purposes of this specification and the subsequent claims, the term "mixed plastic recycled polyethylene composition" means a polymeric material comprising, in addition to other polymeric components of any nature, units primarily derived from ethylene. For example, such polymeric components may be derived from monomeric units derived from alpha olefins (e.g., propylene, butene, octene, etc.), styrene derivatives (e.g., vinyl styrene), substituted and unsubstituted acrylic acid esters, substituted and unsubstituted methacrylic acid esters. The quantitative determination of the ethylene content of the ethylene content may be carried out by the quantitative determination of the ethylene content of the ethylene content. 13 C{ 1 H}NMR measurements were used to identify the polymeric materials in the mixed plastic recycled polyethylene composition. 13 C{ 1 H}NMR measurements, and the quantitative 13 C{ 1 In H NMR measurements, the different units in the polymer chain can be distinguished and quantified. These units are ethylene units (C2 units), units with 3, 4, and 6 carbon atoms, and units with 7 carbon atoms.

[0029] Thus, units with three carbon atoms (C3 units) can be distinguished in the NMR spectrum as isolated C3 units (isolated C3 units) and continuous C3 units (continuous C3 units), indicating that the polymer material contains a propylene-based polymer. These continuous C3 units can also be identified as PP units. Therefore, the continuous C3 units can clearly be attributed to the recycled low-density polyethylene fraction (A), because the virgin high-density polyethylene components (B) and / or (C) in the mixed plastic recycled polyethylene composition according to the present invention generally do not include any propylene-based polymer components.

[0030] Units with 3, 4, 6 and 7 carbon atoms describe these units in the NMR spectrum, which are derived from two carbon atoms in the polymer backbone and short side chains or branches of 1 carbon atom (isolated C3 unit), 2 carbon atoms (C4 unit), 4 carbon atoms (C6 unit) or 5 carbon atoms (C7 unit).

[0031] The units having 3, 4 and 6 carbon atoms (isolated C3, C4 and C6 units) can be derived from incorporated comonomers (propylene, 1-butene and 1-hexene comonomers) or from short chain branches formed by free radical polymerization.

[0032] The units with 7 carbon atoms (C7 units) can clearly be attributed to the recycled low density polyethylene fraction (A) since they cannot be derived from any comonomer. 1-heptene monomer is not used for copolymerization. Instead, the C7 units represent the LDPE present in the recycle. It has been found that the amount of C7 units in the LDPE resin is always within a specific range. Therefore, by quantitative 13 C{ 1 The amount of C7 units determined by H}NMR measurement can be used to calculate the amount of LDPE in the polyethylene composition. Thus, the amount of continuous C3 units, isolated C3 units, C4 units, C6 units and C7 units is quantified as follows 13 C{ 1 The LDPE content was measured by H NMR measurements, while the LDPE content was calculated based on the amount of C7 units as described below.

[0033] The total amount of ethylene units (C2 units) is due to those units in the polymer chain which do not have short side chains of 1 to 5 carbon atoms, in addition to the units due to LDPE (ie units with longer side chain branches of more than 6 carbon atoms).

[0034] The mixed plastic recycled polyethylene composition of the present invention has a tensile strain at break of at least 500%, preferably at least 520%, more preferably at least 530%, even more preferably at least 550%, after 2000 hours of weathering according to EN ISO 4892-2 and measured according to ISO 527-1 on compression molded ISO 527-2 / 5A specimens as described herein.

[0035] The mixed plastic recycled polyethylene composition of the present invention preferably has an oxidative induction time (OIT) of not less than 50 minutes, more preferably not less than 60 minutes at 200°C, as determined as described in the experimental section below.

[0036] Recycled low-density polyethylene fraction (A)

[0037] The recycled low density polyethylene fraction (A) represents the starting primary blend comprising mixed plastic polyethylene as described above. Typically, other components may be present, such as fillers, including organic and inorganic fillers, such as talc, chalk, carbon black, and other pigments, such as TiO2, as well as paper and cellulose. In a particular and preferred embodiment, the waste stream is a consumer waste stream, which may be derived from a conventional collection system, such as that implemented in the European Union. The post-consumer waste is characterized by a limonene content of 0.1 to 500 mg / kg (determined by standard addition using solid phase microextraction (HS-SPME-GC-MS)).

[0038] The recycled low-density polyethylene fraction (A) used herein is commercially available. A suitable recyclate is available, for example, from Ecoplast Kunststoffrecycling GmbH.

[0039] One component of the mixed plastic recycled polyethylene composition of the present invention is a recycled low density polyethylene fraction (A) having a crystallization temperature of not less than 106°C, preferably not less than 107°C, more preferably not less than 108°C.

[0040] The recycled low density polyethylene fraction (A) contained in the mixed plastic recycled polyethylene composition of the present invention accounts for at least 35 weight %, preferably at least 40 weight %, and more preferably at least 48 weight % of the total mixed plastic recycled polyethylene composition.

[0041] Preferably, at least 90 wt.-%, more preferably at least 95 wt.-%, even more preferably 100 wt.-% of the recycled low density polyethylene fraction (A) originates from post-consumer waste and / or post-industrial waste, and has a melt flow rate (ISO 1133, 2.16 kg, 190°C) of preferably 0.1 to 1.5 g / 10 min, more preferably 0.3 to 1.4 g / 10 min, and a density of preferably 910 to 945 kg / m 3 , more preferably 915 to 942 kg / m 3 , even more preferably 920 to 940 kg / m 3 , the total amount of ethylene units (C2 units) is preferably 80.00 to 96.00 wt %, more preferably 82.50 to 95.50 wt %, even more preferably 85.00 to 95.50 wt %, more preferably 87.50 to 95.00 wt %, wherein the total amount of C2 units is based on the total weight of the monomer units in the recovered low density polyethylene fraction (A) and is based on the quantitative 13 C{ 1 H} NMR measurements The measurements were performed as described in the experimental section below.

[0042] The recycled low density polyethylene fraction (A) may preferably contain a total amount of 0.20 to 6.50 wt. %, more preferably 0.40 to 6.00 wt. %, more preferably 0.60 to 5.50 wt. %, even more preferably 0.75 to 5.00 wt. % of continuous units with 3 carbon atoms corresponding to polypropylene (continuous C3 units). Thus, the total amount of C2 units and continuous C3 units is based on the total weight of the monomer units in the mixed plastic polyethylene primary recycled blend (A) and is quantitatively 13 C{ 1 H} NMR measurement was performed.

[0043] In addition to C2 units and continuous C3 units, the recovered low density polyethylene fraction (A) may also contain units having 3, 4, 6 or more carbon atoms, so that the recovered low density polyethylene fraction (A) may contain a mixture of ethylene units and units having a total of 3, 4, 6 and 7 or more carbon atoms.

[0044] The recovered low density polyethylene fraction (A) preferably has one or more of the following properties in any combination, more preferably all of the following properties:

[0045] - melt flow rate (ISO 1133, 5.0 kg, 190 ° C) of 1.5 to 5.0 g / 10 min, more preferably 1.8 to 4.0 g / 10 min; melt flow rate (ISO 1133, 21.6 kg, 190 ° C) of 20.0 to 50.0 g / 10 min, more preferably 25.0 to 45.0 g / 10 min;

[0046] - Polydispersity index PI is 1.0 to 3.5s 1 , more preferably 1.2 to 3.0s 1 ;determined as described in the Experimental section below;

[0047] - Complex viscosity at a frequency of 300 rad / s, eta 300 , is 500 to 750 Pa-s, more preferably 550 to 700 Pa-s; determined as described in the experimental section below;

[0048] - Complex viscosity at a frequency of 0.05 rad / s, eta 0.05 , is from 15,000 to 30,000 Pa-s, more preferably from 16,000 to 27,500 Pa-s, as determined as described in the Experimental Section below;

[0049] - a Shore D hardness measured after 3 seconds according to ISO 868, Shore D 3s, of 45 to 65, more preferably of 48 to 60, as determined as described in the experimental part below;

[0050] - a xylene heat insoluble content, XHU, of 0.01 to 1.0% by weight, more preferably of 0.1 to 0.5% by weight, determined as described in the experimental part below;

[0051] - an ash content of 0.01 to 2.5% by weight, more preferably 0.1 to 2.0% by weight,

[0052] The recycled low density polyethylene fraction (A) preferably has a relatively low gel content, preferably a gel content of gels with a size of greater than 600 μm to 1000 μm not exceeding 1200 gels / m 2 , more preferably not more than 1000 gels / m 2The lower limit of gel content for gels with a size greater than 600 μm to 1000 μm is usually 20 gels / m 2 , preferably 50 gels / m 2 .

[0053] The content of any of Co, Fe, Cu, Mo, Ti and Zn in the recovered low density polyethylene fraction (A) is preferably not more than 400 ppm, more preferably not more than 350 ppm, even more preferably not more than 300 ppm, as determined by x-ray fluorescence (XRF) as described in the experimental part below.

[0054] additive

[0055] The mixed plastic recycled polyethylene composition according to the present invention comprises at least one HALS UV stabilizer. The HALS UV stabilizer is preferably used in an amount of 0.28 to 1.3 wt%, more preferably 0.30 to 1.2 wt%, and even more preferably 0.35 to 1.2 wt%, based on the total weight of the mixed plastic recycled polyethylene composition.

[0056] Hindered amine light stabilizers (HALS) are compounds containing amine functional groups that can be used as stabilizers. Detailed information has been published elsewhere, for example in Zweifel, Hans; Maier, Ralph D.; Schiller, Michael (2009). Plastics additives handbook (6th ed.). Munich: Hanser. These compounds are generally 2,2,6,6-tetramethylpiperidine derivatives containing at least one group of formula (I):

[0057]

[0058] wherein R1 and R2 can be any suitable substituents independently selected from, for example, hydrogen, hydroxyl, linear or branched alkyl, linear or branched amine, linear or branched carboxylic acid, linear or branched ester and linear or branched ether, and Rx can be hydrogen or methyl.

[0059] Examples and details of suitable HALS have been published elsewhere, for example in Zweifel, Hans; Maier, Ralph D.; Schiller, Michael (2009): Plastics additives handbook (6th ed.). Munich: Hanser.

[0060] Preferably, the HALS UV stabilizer is a compound derived from a substituted piperidinyl compound, in particular any compound derived from an alkyl-substituted piperidinyl, piperidinyl or piperazinone compound or a substituted alkoxypiperidinyl compound. Preferably, the HALS UV stabilizer may be selected from bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate (e.g. UV70), mixtures of esters of 2,2,6,6-tetramethyl-4-piperidinol and fatty acids (primarily from stearic acid) (e.g. UV-3853), polymers of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol (e.g. UV62 microbeads), poly((6-((1,1,3,3-tetramethylbutyl)amino)-1,3,5-triazine-2,4-diyl)(2,2,6,6-tetramethyl-4-piperidinyl)imino)-1,6-hexanediyl((2,2,6,6-tetramethyl-4-piperidinyl)imino)) (e.g., Sabostab UV 94 from Sabo).

[0061] Typically, HALS additives are classified according to their molecular weight, i.e., high molecular weight HALS when Mw>2000 g / mol and low molecular weight HALS when Mw is below 1000. Preferably, at least one HALS additive used in the composition of the present invention is of high molecular weight. A particularly preferred HALS UV stabilizer is poly((6-((1,1,3,3-tetramethylbutyl)amino)-1,3,5-triazine-2,4-diyl)(2,2,6,6-tetramethyl-4-piperidinyl)imino)-1,6-hexanediyl((2,2,6,6-tetramethyl-4-piperidinyl)imino)), available from Sabo under the trade name UV94 was purchased commercially.

[0062] The mixed plastic recycled polyethylene composition according to the present invention comprises at least one metal deactivator, which preferably does not include alkylhydroxyphenylalkanoylhydrazines. Preferably, the metal deactivator is a compound derived from a substituted aromatic carboxylate compound, in particular any compound derived from an alkyl-substituted hydroxyphenylcarboxylate compound. A particularly preferred metal deactivator is (1,2-dioxoethylene)-bis(iminoethylene)-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), commercially available from Palmarole under the trade name Palmarole MDA.P.11.

[0063] The metal deactivator is preferably used in an amount of 0.05 to 0.50 wt%, more preferably 0.06 to 0.45 wt%, even more preferably 0.08 to 0.40 wt%, based on the total weight of the mixed plastic recycled polyethylene composition.

[0064] The mixed plastic recycled polyethylene composition according to the present invention may preferably comprise at least one phenolic antioxidant, preferably in an amount of 1000 to 3000 ppm, more preferably 1200 to 2500 ppm, based on the weight of the total composition.

[0065] The at least one phenolic antioxidant is preferably a sterically hindered phenolic antioxidant and may preferably be selected from the following group: 2,6-di-tert-butyl-4-methylphenol (e.g. CP), [octadecyl 3-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate] (e.g. 1076), phenylpropionic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxythiodi-2,1-ethanediyl ester ( 1035), [pentaerythritol tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate] (e.g. 1010); 1,3,5-trimethyl-2,4,6-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)]benzene (e.g. 1330(FF)), 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-isocyanurate (e.g. 3114), bis-[3,3-bis-(4'-hydroxy-3'-tert-butylphenyl)butyric acid]-ethylene glycol ester (e.g. O 3P) and 4,4'-thiobis(2-tert-butyl-5-methylphenol) (Sumilizer WX-RC), or a combination thereof.

[0066] The mixed plastic recycled polyethylene composition of the present invention may preferably contain at least one phosphorus-based antioxidant, preferably in an amount of 400 to 1500 ppm, more preferably 500 to 1200 ppm, based on the weight of the total composition.

[0067] The at least one phosphorus antioxidant may be preferably selected from the following group: [bis(2-methyl-4,6-bis(1,1-dimethylethyl)phenyl)ethyl phosphite] (e.g. Irgafos 38), [tris(2,4-di-tert-butylphenyl)phosphite] (e.g. 168), tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenyl diphosphite (e.g. P-EPQ), distearyl pentaerythritol diphosphite (e.g. ADK-STAB PEP-8T), bis(2,4-dicumylphenyl)pentaerythritol diphosphite (e.g. S-9228) and [2,4,6-tri-tert-butylphenylcyclobutylethylpropylene glycol phosphite] (e.g. 641).

[0068] Virgin polyethylene components

[0069] The mixed plastic recycled polyethylene composition according to the present invention comprises a first virgin high density polyethylene component (B) and optionally a second virgin high density polyethylene component (C), optionally blended with carbon black.

[0070] The first virgin high density polyethylene component (B) may preferably comprise at least one bimodal polyethylene, which may preferably comprise a polyethylene homopolymer and a polyethylene copolymer. The copolymer may be based on ethylene and 1-butene as a comonomer. Preferably, based on the gross weight of the polymer, the content of 1-butene in the polymer is in the range of 0.1 to 4 % by weight, more preferably in the range of 0.5 to 3.5 % by weight, even more preferably in the range of 1.5 to 3.0 % by weight, for example 2.5 % by weight.

[0071] The melt flow rate (ISO 1133, 2.16 kg, 190°C) of the first virgin high-density polyethylene component (B) is preferably 0.1 to 1.2 g / 10 min, more preferably 0.3 to 0.7 g / 10 min, and the density is preferably 940 to 970 kg / m 3 , more preferably 942 to 962 kg / m 3 .

[0072] The second virgin high density polyethylene component (C) preferably has a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.01 to 0.1 g / 10 min, more preferably 0.02 to 0.08 g / 10 min, or a melt flow rate (ISO 1133, 5.0 kg, 190°C) of 0.05 to 1.0 g / 10 min, more preferably 0.1 to 0.5 g / 10 min, and a density of 940 to 965 kg / m 3 , more preferably 945 to 962 kg / m 3 .

[0073] The second virgin high density polyethylene component (C) may preferably comprise at least one bimodal polyethylene, and may preferably comprise a polyethylene homopolymer and a polyethylene copolymer. The copolymer may be based on ethylene and 1-hexene as a comonomer. Preferably, based on the gross weight of the polymer, the content of 1-hexene in the polymer is in the range of 0.1 to 4 % by weight, more preferably in the range of 0.5 to 3 % by weight, and even more preferably in the range of 1.5 to 2.5 % by weight, for example 2 % by weight.

[0074] The melt flow rate MFR5 (190°C, 5 kg, measured according to ISO 1133) of the second virgin high density polyethylene component (C) may be in the range of 0.1 to 1 g / 10 min, preferably 0.15 to 0.5 g / 10 min, more preferably 0.2 to 0.3 g / 10 min. The density of the second virgin high density polyethylene component (C) may be 930 to 970 kg / m 3 , preferably 940-965kg / cm 3 .

[0075] The slow crack growth resistance, SCG, is at least 2.000 h, more preferably at least 5.000 h, in a notched pipe test (9.2 bar, 80° C.) performed on a SDR11 pipe with an outer diameter of 110 mm according to ISO 13479-2009.

[0076] The first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C) may comprise carbon black or other pigments, and their amount is no more than 5 % by weight, and is preferably no more than 3 % by weight. However, it is preferred that the first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C) do not comprise carbon black. It is further preferred that the first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C) do not comprise any pigment except carbon black, more preferably do not comprise pigment substantially.

[0077] The first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C) may preferably comprise a copolymer of ethylene and one or more comonomer units selected from alpha-olefins having 3 to 6 carbon atoms. More preferably, they may comprise a copolymer of ethylene and 1-butene or a copolymer of ethylene and 1-hexene.

[0078] In addition to the above-mentioned polymer components, such as the recycled low density polyethylene fraction (A), the first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C), the mixed plastic recycled polyethylene composition of the present invention may also contain 10% by weight or less, more preferably 9% by weight or less, more preferably 7% by weight or less of additives based on the virgin high density polyethylene component. In addition to the above-mentioned specific additives, suitable additives are additives commonly used with polyolefins, such as stabilizers (e.g., antioxidants), metal scavengers and / or UV stabilizers, antistatic agents and use aids (e.g., processing aids).

[0079] The first virgin high density polyethylene component (B) is preferably present in the mixed plastic recycled polyethylene composition of the present invention in an amount of 55 wt % or less, preferably 45 wt % or less, more preferably 40 wt % or less. Preferably, the first virgin high density polyethylene component (B) is present in the mixed plastic recycled polyethylene composition of the present invention in an amount of at least 15 wt %, more preferably at least 20 wt %, even more preferably at least 25 wt %. Based on the total weight of the composition, preferably, the content ranges from 15 to 50 wt %, more preferably from 20 to 50 wt %, even more preferably from 25 to 50 wt % or from 27.5 to 60 wt %, even more preferably from 30 to 50 wt %.

[0080] If present, the second virgin high density polyethylene component (C) is preferably present in the mixed plastic recycled polyethylene composition of the present invention in an amount of 1 to 20 wt%, more preferably 2 to 18 wt%, more preferably 3 to 17 wt%, even more preferably 4 to 16 wt%, more preferably 5 to 15 wt%, based on the total weight of the composition.

[0081] The first virgin high density polyethylene component (B) and / or the second virgin high density polyethylene component (C) may preferably be bimodal polyethylene. The properties and characteristics of the virgin bimodal polyethylene that can be used in the mixed plastic recycled polyethylene composition of the present invention are described below.

[0082] The term "bimodal" in this context means that the polymer consists of two polyethylene fractions which have been produced under different polymerisation conditions, resulting in fractions having different (weight average) molecular weights and molecular weight distributions. The form of the molecular weight distribution curve of a multimodal polymer, i.e. the appearance of a graph of the polymer weight fraction as a function of its molecular weight, will show two or more maxima or will generally be significantly broader than the curve for a single fraction.

[0083] The bimodal polyethylene preferably comprises a polyethylene homopolymer and a polyethylene copolymer.

[0084] Ethylene homopolymer refers to a polymer formed essentially only from ethylene monomer units (ie, more than 99.9% by weight of ethylene). It should be understood that since industrial ethylene contains trace amounts of other monomers, trace amounts of other monomers may be present.

[0085] Polyethylene copolymers are made of ethylene and at least one other comonomer having at least 4 carbon atoms (e.g. C 4-20 The comonomer is preferably an α-olefin, especially an α-olefin having 4 to 8 carbon atoms. Preferably, the comonomer is selected from 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1,7-octadiene and 7-methyl-1,6-octadiene. 1-Butene and 1-hexene are preferably used.

[0086] Methods for obtaining such polymers are well known to those skilled in the art and are described, for example, in WO 2015 / 121161 A1.

[0087] method

[0088] The mixed plastic recycled polyethylene composition of the present invention can be prepared by the following method, which comprises the following steps: in the presence of at least one HALS UV stabilizer and at least one metal deactivator, in the presence of a first virgin high-density polyethylene component (B) and optionally a second virgin high-density polyethylene component (C), melt mixing and extruding a recycled polyethylene fraction (A) in an extruder. Alternatively, the obtained mixed plastic recycled polyethylene composition can be pelletized in a twin-screw extruder at a screw speed of not more than 400 rpm and a barrel temperature of not more than 250°C.

[0089] Products

[0090] The present invention also relates to an article made from the mixed plastic recycled polyethylene composition according to the present invention, wherein the mixed plastic recycled polyethylene composition represents at least 85 wt. %, preferably at least 90 wt. %, more preferably at least 92 wt. % of the total composition from which the article is made.

[0091] The article is preferably a jacketing material comprised in at least one layer of a power cable.

[0092] use

[0093] The present invention also relates to the use of the mixed plastic recycled polyethylene composition according to the present invention in wire and cable applications.

[0094] The mixed plastic recycled polyethylene composition according to the present invention can significantly improve the mechanical and thermal light stability of the cable layer when used in wire or cable applications. It can also improve the weather resistance and OIT properties of the recycled polyethylene composition.

[0095] Experimental part

[0096] method

[0097] a) Melt flow rate

[0098] The melt flow rate is 2.16 kg (MFR2), 5.0 kg (MFR5) or 21.6 kg (MFR 21 The melt flow rate is the amount of polymer (in grams) that is extruded in 10 minutes at a temperature of 190° C. and a load of 2.16 kg, 5.0 kg or 21.6 kg using a test apparatus standardized according to ISO 1133.

[0099] b) Density

[0100] To determine the density of non-foamed plastics, the immersion method (Archimedes' principle) according to ISO 1183-1:2012 is used. The sample is weighed in air and immersed in a liquid (isododecane) with a lower density than the sample. The force applied is equal to the weight of the liquid displaced by the sample volume.

[0101] The test was performed on PE (Polyethylene) compression molded plaques. For the compression molding process, the following parameters were used:

[0102]

[0103] Conditioning time: 24 hours after compression molding (PE)

[0104] Test temperature: 23℃

[0105] Immersion liquid: Isododecane

[0106] Buoyancy correction: None

[0107] c) NMR measurement

[0108] c-1) NMR measurement of virgin polyethylene

[0109] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the virgin polymer.

[0110] Quantitative measurements were recorded in the melt using a Bruker Avance III 500 NMR spectrometer. 13 C{ 1 H}NMR spectrum, 1 H and 13 C operated at 500.13 and 125.76 MHz, respectively. All spectra were obtained using 13Recordings were made at 150° using a C-optimized 7 mm magic angle spinning (MAS) probehead, with nitrogen used for all pneumatics. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconium oxide MAS rotor and spun at 4 kHz. This setup was chosen primarily for the high sensitivity required for rapid identification and accurate quantification (Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382., Parkinson, M., Klimke, K., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208: 2128., Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373). Using standard single pulse excitation, transient NOE (Pollard, M., Klimke, K., Graf, R., Spiess, H.W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37: 813., Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, HW, Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382.) and the RS-HEPT decoupling scheme (Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239, Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198). A total of 1024 (1k) transients were acquired for each spectrum.

[0111] Use custom spectral analysis automation program processing, integration and quantification 13 C{ 1 H} NMR spectra and quantitative identity were determined. All chemical shifts were internally referenced to the bulk methylene signal (δ) at 30.00 ppm (J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201).

[0112] A characteristic signal corresponding to the incorporation of 1-butene was observed ((J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.) and all levels were calculated relative to all other monomers present in the polymer with a limit of quantification of 0.2 mol% butene.

[0113] Characteristic signals arising from isolated 1-butene incorporation (i.e., EEBEE comonomer sequences) were observed. Isolated 1-butene incorporation was quantified using the integration of the 39.8 ppm signal assigned to the *B2 site, taking into account the number of reported sites per comonomer:

[0114] B=I* B2

[0115] When a characteristic signal resulting from continuous 1-butene incorporation (i.e., EBBE comonomer sequences) was observed, the integration of the 39.3 ppm signal assigned to the ααB2B2 site was used to quantify this continuous 1-butene incorporation, taking into account the number of reported sites per comonomer:

[0116] BB=2*Iαα B2B2

[0117] When a characteristic signal arising from discontinuous 1-butene incorporation (i.e., EBEBE comonomer sequences) was also observed, the integration of the 24.7 ppm signal assigned to the ββB2B2 site was used to quantify this discontinuous 1-butene incorporation, taking into account the number of reported sites per comonomer:

[0118] BEB=2*Iββ B2B2

[0119] Since the *B2 and *βB2B2 sites of isolated (EEBEE) and discontinuously incorporated (EBEBE) 1-butenes overlap, the total amount of isolated 1-butene incorporation was corrected for the amount of discontinuous 1-butene present:

[0120] B=I* B2 -2*Iββ B2B2

[0121] Since no other signals indicative of other comonomer sequences (i.e., butene chain initiation) were observed, the total 1-butene comonomer content was calculated based solely on the amounts of isolated (EEBEE), continuous (EBBE), and discontinuous (EBEBE) 1-butene comonomer sequences:

[0122] B 总 =B+BB+BEB

[0123] Characteristic signals arising from saturated end groups were observed. The content of such saturated end groups was quantified using the integrated average of the signals at 22.8 and 32.2 ppm, assigned to the 2s and 3s sites, respectively:

[0124] S=(1 / 2)*(I 2S +I 3S )

[0125] The relative amount of ethylene was quantified using the integration of the bulk methylene (δ+) signal at 30.00 ppm:

[0126] E=(1 / 2)*Iδ +

[0127] The total ethylene comonomer content is calculated from the bulk methylene signal and takes into account the presence of ethylene units in other observed comonomer sequences or end groups:

[0128] E 总 =E+(5 / 2)*B+(7 / 2)*BB+(9 / 2)*BEB+(3 / 2)*S

[0129] The total mole fraction of 1-butene in the polymer is then calculated:

[0130] fB=B 总 / (E 总 +B 总 )

[0131] The total comonomer incorporation (mole percent) of 1-butene was calculated from the mole fractions in the usual manner:

[0132] B[mol%]=100*fB

[0133] The total comonomer incorporation (weight percent) of 1-butene was calculated from the mole fractions in the standard manner:

[0134] B[wt%]=100*(fB*56.11) / ((fB*56.11)+((1-fB)*28.05))

[0135] c-2) NMR measurement of recovered polyethylene

[0136] Quantitative analysis was performed in solution using a Bruker Avance III 400 MHz NMR spectrometer. 13 C{ 1 H}NMR spectrum, 1 H and 13 C were operated at 400.15 and 100.62 MHz, respectively. All spectra were obtained using 13Recordings were made at 125°C using a C-optimized 10mm extended temperature probe, with nitrogen used for all pneumatics. Approximately 200mg of material was dissolved in 3ml of 1,2-tetrachloroethane-d2 (TCE-d2) along with chromium-(III) acetylacetonate (Cr(acac)3) to yield a 65mM solution of the relaxant in the solvent {singh09}. To ensure a homogeneous solution, the NMR tube was further heated in a rotary oven for at least 1 hour after initial sample preparation in a heating block. After insertion into the magnet, the tube was rotated at 10Hz. This setup was chosen primarily for the high resolution and quantification required for accurate quantification of ethylene content. Standard single-pulse excitation was employed without NOE, using an optimized tip angle, a 1s recycle delay, and a dual-level WALTZ16 decoupling scheme {zhou07, busico07}. A total of 6144 (6k) transients were acquired for each spectrum.

[0137] Processing, integration and quantification using a proprietary computer program 13 C{ 1 H} NMR spectra were obtained, and relevant quantitative properties were determined from the integration. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. Characteristic signals corresponding to polyethylene and polypropylene with different short chain branches (B1, B2, B4, B5, B6 plus) were observed {randall89, brandolini00}.

[0138] Characteristic signals corresponding to the presence of polyethylene were observed: polyethylene contained isolated B1 branches (starB1 33.3 ppm), isolated B2 branches (starB2 39.8 ppm), isolated B4 branches (twoB4 23.4 ppm), isolated B5 branches (threeB5 32.8 ppm), all branches longer than four carbons (starB4plus 38.3 ppm), and the third carbon from the end of a saturated fatty chain (3s 32.2 ppm). The intensity of the combined ethylene backbone methine carbons (ddg), including the polyethylene backbone carbons (dd 30.0 ppm), the γ-carbon (g 29.6 ppm), the 4s carbon, and the threeB4 carbons (compensated later), ranged between 30.9 ppm and 29.3 ppm, excluding Tββ in polypropylene. The amount of C2-related carbons was quantified using all of the aforementioned signals according to the following formula:

[0139] fC C2总 =(Iddg–ItwoB4)+(IstarB1*6)+(IstarB2*7)+(ItwoB4*9)+I(threeB5*10)+((IstarB4plus-ItwoB4-IthreeB5)*7)+(I3s*3)

[0140] Characteristic signals corresponding to the presence of polypropylene (PP, continuous C3) were observed at 46.7 ppm, 29.0 ppm, and 22.0 ppm. The amount of PP-related carbon was quantified using the Sαα integral at 46.6 ppm:

[0141] fC PP =Isαα*3

[0142] The weight percentages of C2 fraction and polypropylene can be quantified according to the following formula:

[0143] wt C2级分 =fC C2总 *100 / (fC C2总 +fCPP)

[0144] wt PP =fC PP *100 / (fC C2总 +fCPP)

[0145] Observe the characteristic signals corresponding to the various short chain branches and quantify their weight percentages. Since the relevant branches will be α-olefins, first quantify the weight fraction of each:

[0146] fwtC2=fC C2总 –((IstarB1*3)–(IstarB2*4)–(ItwoB4*6)–(IthreeB5*7)

[0147] fwtC3(isolated C3)=IstarB1*3

[0148] fwtC4=IstarB2*4

[0149] fwtC6=ItwoB4*6

[0150] fwtC7=IthreeB5*7

[0151] Normalization of all weight fractions yields the amount of weight percentages of all relevant branches:

[0152] fsum wt％总 =fwtC2+fwtC3+fwtC4+fwtC6+fwtC7+fCPP

[0153] wtC2 total = fwtC2*100 / fsum wt％总

[0154] wtC3 total = fwtC3*100 / fsum wt％总

[0155] wtC4 total = fwtC4*100 / fsumwt％总

[0156] wtC6 total = fwtC6*100 / fsum wt％总

[0157] wtC7 total = fwtC7*100 / fsum wt％总

[0158] The LDPE content can be estimated by assuming that the B5 branches (generated solely by ethylene polymerization under high-pressure processes) remain nearly constant in the LDPE. We found that the average B5 content, if quantified as C7, is 1.46 wt%. Based on this assumption, a range of LDPE contents can be estimated (approximately between 20 wt% and 80 wt%), depending on the SNR ratio of the three B5 signals:

[0159] wt% LDPE = wtC7 total * 100 / 1.46

[0160] References:

[0161] zhou07 Zhou,Z.,Kuemmerle,R.,Qiu,X.,Redwine,D.,Cong,R.,Taha,A.,Baugh,D.Winniford,B.,J.Mag.Reson.187(2007)225

[0162] busico07 Busico,V.,Carbonniere,P.,Cipullo,R.,Pellecchia,R.,Severn,J.,Talarico,G.,Macromol.Rapid Commun.2007,28,1128

[0163] singh09 Singh,G.,Kothari,A.,Gupta,V.,Polymer Testing 28 5(2009),475

[0164] randall89 J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.

[0165] brandolini00 AJBrandolini,DDHills,NMR Spectra of Polymers andPolymer Additives,Marcel Dekker Inc.,2000

[0166] d) Tensile properties

[0167] Tensile properties were determined according to ISO 527-2 and were measured on 5A ISO 527-2 dog bones in two laboratories (LA and LB). The dog bone adhesives were either die cut (LA) or ground (LB) from 2 mm thick compression molded plaques. The melt temperature for compression molding was 180°C and the cooling rate was 15°C / min. For samples tested in LA, a test speed of 0.5 mm / min was used to measure tensile modulus and a test speed of 50 mm / min was used to measure all other properties. For samples tested in LB, a speed of 50 mm / min was also used to measure modulus and all other properties. All tests were performed at 23 ± 2°C and 50 ± 10% humidity.

[0168] e) Impact strength (Charpy NIS)

[0169] Impact strength was determined as Charpy notched impact strength at +23° C. according to ISO 179-1eA, with specimen dimensions of 80×10×4 mm, prepared according to ISO 17855-2.

[0170] f) Metal content

[0171] The metal content was determined by X-ray fluorescence (XRF).

[0172] The instrument used for XRF measurements was a Malvern Panalytical wavelength dispersive Zetium (2,4kW). The instrument was calibrated using a Malvern Panalytical polyolefin-based standard set (i.e., Toxel, for Cu in the range 0–25.1 ppm) and a Malvern Panalytical custom calibration standard set according to the table below (for Ti and Zn).

[0173]

[0174] Elements not covered by the standards (Fe, Co, Mo) or present in concentrations outside the calibration standard range were then analyzed using a semi-quantitative mode (Malvern Panalytical's Omnian software). The CH (carbon and hydrogen) content required for semi-quantitative assessment using Omnian was estimated by the software itself.

[0175] The analysis was performed under vacuum on a plate with a diameter of 40 mm and a thickness of 2 mm.

[0176] g) Melting temperature (Tm) and crystallization temperature (Tc) were measured by DSC

[0177] A TA Instruments Q2000 differential scanning calorimeter was used, which was calibrated with indium, zinc, and tin and operated under a nitrogen flow of 50 mL / min. The thermal program used consisted of a first heating step from 0 to 180°C to eliminate previous thermal history and a cooling step at 10°C / min. The melting behavior was obtained by performing a second heating scan from 0 to 180°C at a rate of 10°C / min. The crystallization temperature and melting temperature were taken as the peak of the cooling and second heating scans, respectively. The DSC trace was integrated from 30°C to the end of the melting peak to estimate the melting enthalpy (heat of solution).

[0178] h) Dynamic shear measurement (frequency sweep measurement)

[0179] The characterization of polymer compositions or polymer melts by dynamic shear measurements, as described above or below, complies with ISO standards 6721-1 and 6721-10. The measurements were performed on an Anton Paar MCR501 stress-controlled rotational rheometer equipped with 25 mm parallel-plate geometry. The measurements were performed on compression-molded plaques using a nitrogen atmosphere and strain settings within the linear viscoelastic range. The oscillatory shear tests were performed at 190°C, with an applied frequency range of 0.01 to 600 rad / s and a 1.3 mm gap.

[0180] In dynamic shear experiments, the probe is subjected to uniform deformation under sinusoidally varying shear strain or shear stress (strain and stress controlled modes, respectively). In controlled strain experiments, the probe is subjected to a sinusoidal strain, which can be expressed as

[0181] γ(t)=γ0 sin (ωt) (1)

[0182] If the applied strain is within the linear viscoelastic range, the resulting sinusoidal stress response can be expressed as

[0183] σ(t)=σ0 sin(ωt + δ) (2)

[0184] in

[0185] σ0 and γ0 are the stress and strain amplitudes, respectively

[0186] ω is the angular frequency

[0187] δ is the phase shift (loss angle between the applied strain and the stress response)

[0188] t is the time

[0189] Dynamic test results are usually expressed through 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 tanδ, which can be expressed as follows:

[0190]

[0191] The so-called shear thinning index is determined in relation to the MWD, independent of the Mw, as described in Equation 9.

[0192]

[0193] For example, SHI (2.7 / 210) It is defined as the complex viscosity value (in Pa s) determined when G* is equal to 2.7 kPa, divided by the complex viscosity value (in Pa s) determined when G* is equal to 210 kPa.

[0194] The values ​​of storage modulus (G'), loss modulus (G"), complex modulus (G*), and complex viscosity (η*) were obtained as a function of frequency (ω).

[0195] So, for example, η* 300rad / s (eta*300rad / s) is used as the abbreviation for the complex viscosity at a frequency of 300rad / s, η* 0.05rad / s (eta*0.05 rad / s) is used as an abbreviation for the complex viscosity at a frequency of 0.05 rad / s.

[0196] The loss tangent tanδ (delta) is defined as the ratio of the loss modulus (G") to the storage modulus (G') at a given frequency. Thus, for example, tan 0.05 Used as an abbreviation for the ratio of the loss modulus (G") to the storage modulus (G') at 0.05 rad / s, tan 300 Abbreviation used as the ratio of loss modulus (G") to storage modulus (G') at 300 rad / s.

[0197] Elastic balance tan 0.05 / tan 300 Defined as loss tangent tan 0.05 and loss tangent tan 300 ratio.

[0198] In addition to the rheological functions described above, other rheological parameters can also be determined, such as the so-called elasticity index EI(x). The elasticity index EI(x) is the value of the storage modulus (G') determined at a value of x kPa for the loss modulus (G") and can be described by Equation 10.

[0199] El(x)=G′(G″=xkPα)[Pa] (10)

[0200] For example, EI(5 kPa) is defined by the value of the storage modulus (G'), which is determined by G" being equal to 5 kPa.

[0201] The polydispersity index PI is defined by Equation 11.

[0202]

[0203] where ω COP is the crossover frequency, determined as the angular frequency at which the storage modulus G' is equal to the loss modulus G".

[0204] These values ​​were determined using the single-point interpolation procedure defined in the Rheoplus software. If a given G* value was not experimentally reached, it was determined by extrapolation using the same procedure as before. In both cases (interpolation or extrapolation), the Rheoplus options "Interpolate y-values ​​into x-values ​​of parameter" and "Logarithmic interpolation type" were used.

[0205] References:

[0206] [1]Rheological characterization of polyethylene fractions” Heino, EL, Lehtinen, A., Tanner J., J.,Neste Oy,Porvoo,Finland,Theor.Appl.Rheol.,Proc.Int.Congr.Rheol,11th(1992),1,360-362

[0207] [2]The influence of molecular structure on some rheologicalproperties of polyethylene", Heino, EL, Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995.).

[0208] [3]Definition of terms relating to the non-ultimate mechanicalproperties of polymers,Pure&Appl.Chem.,Vol.70,No.3,pp.701-754,1998.

[0209] i) OIT measurement

[0210] The oxidation induction time (OIT) at 200°C was determined using a TA Instrument Q20 according to ISO 11357-6. The instrument was calibrated using indium (In) and tin (Sn) according to ISO 11357-1. The maximum error in the calibration temperature was less than 0.1 K. A sample of each polymer (cylindrical, 5 mm in diameter, 1 ± 0.1 mm in thickness) weighing 10 ± 2 mg was placed in an open aluminum crucible and heated in nitrogen (>99.95 vol.% N2, <5 ppm O2) at 20°C min -1 The heating rate was from 25°C to 200°C, and the gas flow rate was 50 mL min -1 , let it stand for 5 minutes, then switch the air to pure oxygen (>99.95vol.%O2) at a flow rate of 50mL min -1 The sample was maintained at a constant temperature and the exotherm associated with the oxidation was recorded. The oxidation induction time is the time interval between the start of the oxygen flow and the onset of the oxidation reaction. Each data point presented is the average of two independent measurements.

[0211] j) Weather resistance

[0212] 5A ISO 527-2 dog bones were exposed to xenon arc light according to method a (humidified room air) of ISO 4892-2 "Exposure methods for laboratory light sources". The machine used for conditioning was an Atlas-Ci5000 weatherometer, and the conditions were as follows:

[0213]

[0214] k) Shore D hardness

[0215] Shore D hardness is measured on compression-molded specimens with a thickness of 4 mm according to ISO 868. The Shore D hardness is measured 3 seconds after the presser foot comes into close contact with the test specimen.

[0216] l) Ash content

[0217] Thermogravimetric analysis (TGA) experiments were performed using a Perkin Elmer TGA 8000. Approximately 10-20 mg of material was placed in a platinum pan. The temperature was equilibrated at 50°C for 10 minutes and then increased to 950°C at 20°C / min under nitrogen. Ash content was calculated as weight percent at 850°C.

[0218] m) Gel count (OCS)

[0219] Cast film samples are produced and optically inspected on a small laboratory cast film line equipped with camera detection from Optical Control Systems GmbH.

[0220] The production line consists of an extruder with a screw diameter of The L / D ratio was 25. The extruder temperature profile was set between 170 and 210°C in five zones. The screw speed was 30 rpm. The extruder was followed by a die with a width of 150 mm and a fixed die gap of 0.5 mm. The film thickness produced was 70 μm. During extrusion, the cooling roller temperature was set to 50°C. During the extrusion process, 10 m 2 Gel and contaminants on a film. The camera has a resolution of 25 μm x 25 (on the film). Gel and contaminants are classified into four size classes (100-299 μm; 300-599 μm; 600-1000 μm; >1000 μm).

[0221] n) Xylene insoluble matter content (XHU)

[0222] The xylene heat-insoluble content (XHU) is analyzed in accordance with ISO 10147. Therefore, 1 g of sample is weighed to the nearest 0.1 mg (m1) and placed in a stainless steel mesh bag made of the following material ("stainless steel quality 1.4401"). The bag with the polymer sample is placed to the nearest 0.1 mg (m2) in a round flask containing 700 mL of xylene (o-xylene or p-xylene, chromatographic purity >98%). The xylene is kept under reflux for 5 hours. The bag with the insoluble matter is removed from the flask and the polymer solution residue is washed with 700 mL of fresh xylene under reflux for 30 minutes. The bag is then removed from the flask and dried in vacuo at 90°C to constant weight. After cooling the bag to room temperature in a desiccator, the bag is weighed to the nearest 0.1 mg (m3).

[0223]

[0224] XHU = xylene heat insoluble matter content

[0225] m1 = sample weight (g)

[0226] m2 = weight of the bag containing the sample (g)

[0227] m3 = weight of bag containing insoluble residue (g)

[0228] By evaporating xylene from the xylene solution, a xylene heat soluble fraction can be obtained.

[0229] Example

[0230] The following polymer components were used in the following examples.

[0231] raw materials

[0232] 1) Virgin polymers used for blending:

[0233] Bimodal polyethylene (PE-1)

[0234] PE1 is a natural bimodal high-density polyethylene with a density of 946 kg / m 3 , MFR2 (ISO 1133, 190°C, load 2.16kg) is 0.5g / 10min, MFR5 (ISO 1133, 190°C, load 5kg) is 2g / 10min, MFR 21 (ISO 1133, 190°C, load 21.6 kg) is 36.35 g / 10 min. Further properties are given in Table 1 below.

[0235] Bimodal polyethylene (PE-2)

[0236] PE2 is a natural bimodal high-density polyethylene with a density of 949 kg / m 3 , MFR2 (ISO 1133, 190°C, load 2.16kg) is 0.05g / 10min, MFR5 (ISO 1133, 190°C, load 5kg) is 0.23g / 10min, MFR 21 (ISO 1133, 190° C., load 21.6 kg) is 9.48 g / 10 min. Further properties are listed in Table 1 below.

[0237] Table 1

[0238]

[0239]

[0240] 2). Recycled low-density polyethylene fraction (A) for blending:

[0241] Recycled polyethylene (rPE1) is a recycled low-density polyethylene fraction (A) that is a mixture of low-density and linear low-density polyethylene (LDPE / LLDPE) and is available from Ecoplast Kunststoffrecycling GmbH. The properties of rPE are shown in Table 2 below. Since rPE1 comes from a mechanical recycling process, these properties are expressed as average values ​​based on analytical results from multiple batches.

[0242] Table 2

[0243]

[0244]

[0245] 3) Additives

[0246]

[0247]

[0248] The following Inventive Examples IE1 to IE4 and Comparative Examples CE1 and CE2 were prepared by melt blending on a co-rotating twin-screw extruder (ZSK) according to the table below. The polymer melt mixture was discharged at a screw speed of 300 rpm and pelletized. IE1 and CE1 were prepared using one batch of rPE1; while IE2, IE3, IE4, and CE2 were prepared using another batch. For strict comparison, data for IE1 should be compared with CE1, and data for IE2, IE3, and IE4 should be compared with CE2.

[0249] The results are also shown in Table 4 below.

[0250]

[0251] The above results indicate that the addition of a metal deactivator to a polyethylene composition comprising a recycled low-density polyethylene fraction (A) and at least one virgin polyethylene component significantly increases the OIT and effectively improves the weather resistance and thermal light stability while maintaining the desired mechanical properties, thereby improving the performance of the composition of the present invention in outdoor applications.

Claims

1. A mixed plastic recycled polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.1 to 1.2 g / 10 min; a density of 930 to 955 kg / m 3 , and contains 35% by weight or more of a recovered low-density polyethylene fraction (A) having a crystallization temperature of not less than 106° C.; At least one HALS UV stabilizer; at least one metal deactivator; A first virgin high density polyethylene component (B) and an optional second virgin high density polyethylene component (C), optionally blended with carbon black or other pigments, in, The mixed plastic recycled polyethylene composition has a tensile strain at break of at least 500% after 2000 hours of weathering according to EN ISO 4892-2 and measured according to ISO 527-1 on compression molded ISO 527-2 / 5A specimens as described herein.

2. The mixed plastic recycled polyethylene composition according to claim 1, wherein The metal deactivator is not an alkylhydroxyphenylalkanoylhydrazine.

3. The mixed plastic recycled polyethylene composition according to claim 1 or 2, comprising at least one metal deactivator in an amount of 0.05 to 0.50 wt. %, based on the weight of the total composition.

4. The mixed plastic recycled polyethylene composition according to any one of claims 1 to 3, further comprising at least one phenolic antioxidant, preferably in an amount of 1000 to 3000 ppm based on the weight of the total composition.

5. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, further comprising at least one phosphorus-based antioxidant, preferably in an amount of 400 to 1500 ppm based on the weight of the total composition.

6. The mixed plastic recycled polyethylene composition of any one of the preceding claims, comprising at least one HALS UV stabilizer in an amount of 0.28 to 1.3 wt. %, based on the weight of the total composition.

7. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, wherein The recovered low density polyethylene fraction (A) contains no more than 400 ppm of any of Co, Fe, Cu, Mo, Ti and Zn as determined by X-ray fluorescence (XRF) as described herein.

8. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, wherein The first virgin high-density polyethylene component (B) has a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.1 to 1.2 g / 10 min and a 3 density.

9. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, wherein The second virgin high density polyethylene component (C) has a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.01 to 0.1 g / 10 min, and a 3 density.

10. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, having an Oxidative Induction Time (OIT) at 200°C, measured as described herein, of not less than 50 minutes, preferably not less than 60 minutes.

11. A method for preparing a mixed plastic recycled polyethylene composition according to any one of the preceding claims, comprising the following steps: The recycled polyethylene fraction (A) is melt mixed and extruded in an extruder in the presence of the at least one HALS UV stabilizer and the at least one metal deactivator and in the presence of the first virgin high density polyethylene component (B) and optionally the second virgin high density polyethylene component (C).

12. An article made from the mixed plastic recycled polyethylene composition according to any one of claims 1 to 10, wherein The mixed plastic recycled polyethylene composition comprises at least 85% by weight of the total composition used to make the article.

13. The article according to claim 12, which is a jacketing material for a power cable.

14. Use of the mixed plastic recycled polyethylene composition according to any one of claims 1 to 10 for wire and cable applications.

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