Regenerated polyethylene composition with improved mechanical and optical properties

Abstract

The present invention relates to a hybrid plastic regenerated polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190 DEG C) of from 0.1 to 1.5 g / 10 min; a density of 938 to 985 kg / m3, and comprising 35 wt% or more of a regenerated polyethylene fraction (rPE); wherein the hybrid plastic regenerated polyethylene composition has: (a) a total amount of ethylene units (C2 units) of at least 95.0 wt%, measured by 13C-NMR of the d2-tetrachloroethylene soluble fraction; (b) the total amount of continuous C3 units derived from polypropylene (PP) is from 0 to 3.0 wt%, as determined by a quantitative 13C {1H}-NMR measurement of the soluble fraction; and (c) an environmental stress cracking resistance (ESCR) of at least 1000 hours as determined by the Bell test according to IEC 60811-406 method B wherein the hybrid plastic regenerated polyethylene composition further comprises: at least one native polyethylene component (B), optionally blended with carbon black, and optionally a native polyethylene component (B1) different from the native polyethylene component (B), optionally blended with carbon black, and optionally blended with carbon black, the present invention relates to a hybrid plastic regenerated polyethylene composition comprising at least one thermoplastic elastomer, optionally blended with carbon black, where the hybrid plastic regenerated polyethylene composition has a tear resistance of at least 24 N / mm as determined according to BS 6469 99.1 node. This hybrid plastic regenerated polyethylene composition has high purity in terms of polyethylene content, low contaminant content, high homogeneity, improved mechanical properties, and good optical properties. The invention also relates to a process for its preparation, to the aforementioned regenerated polyethylene fraction (rPE) obtainable or by a process for regenerating a hybrid plastic regenerated stream, to articles made from the aforementioned hybrid plastic regenerated polyethylene composition, and to the use of the aforementioned hybrid plastic regenerated polyethylene composition in wire and cable applications.

Description

Technical Field

[0001] The present invention relates to mixed plastic recycled polyethylene compositions derived from post-consumer recyclates (PCR). Background Art

[0002] The increasing challenge of disposing of plastic waste and the resulting environmental problems have garnered widespread public and industry attention. Consequently, converting plastic waste into a valuable resource for the production of new plastic products has become a crucial issue. The recycling and reuse of plastic materials can offer both environmental and economic benefits.

[0003] Although the recycling of plastic materials began as early as the mid-1990s with the implementation of collection systems that allow for more targeted collection and separation of plastic materials from other household waste, the reuse of plastic materials originating from plastic waste remains limited. So-called post-consumer recycled (PCR) often contains a mixture of different plastics and various contaminants. Methods have now been developed to further purify this PCR.

[0004] Numerous attempts have been made to purify recycled streams derived from post-consumer plastic waste. These include washing, screening, aeration, and distillation. For example, WO 2018 / 046578 A1 discloses a method for producing polyolefin regenerated material from mixed-color polyolefin waste (including packaging waste). The method involves cold-washing the waste with water, then washing it with an alkaline medium at 60°C, and then color-sorting the flakes to obtain a color-sorted fraction enriched in monopolyolefins.

[0005] WO2021 / 074785A1 discloses a polyethylene blend suitable for compression molding or injection molding applications made from recycled polyethylene, the recycled polyethylene comprising 1 wt% to 50 wt% of recycled polyethylene and 50 wt% to 99 wt% of a bimodal polyethylene composition, wherein the recycled polyethylene has a viscosity of 0.916 to 0.970 g / cm3 as measured by ASTM D792. 3 and a melt index I2 of 0.3 to 30 g / 10 min as measured by ASTM D1238 at 190°C using a 2.16 kg load; and wherein the bimodal polyethylene composition has a melt index I2 of 0.930 to 0.970 g / cm3 as measured by ASTM D792 3 A density of 1000 nm and a melt index I2 of 0.1 to 12 g / 10 min as measured by ASTM D1238 at 190° C. using a 2.16 kg load and a B10 ESCR of a time to failure of 10 to 2000 h as measured by ASTM D1693.

[0006] WO2021 / 233818A1, WO2021 / 233819A1 and WO2021 / 233820A1 disclose polyethylene recycled compositions comprising virgin high-density polyethylene (HDPE) suitable for use as sheath materials with acceptable ESCR (environmental stress cracking resistance) performance. All three disclosures use a mixture of at least 50% by weight of virgin HDPE components and commercially available PCR polyethylene, wherein the content of continuous C3 units (PP) exceeds 10% by weight. The ESCR performance of such recycled polyethylene is insufficient and a large amount of contaminants are present. Contamination of recycled polymers generally refers to impurities from the first application of virgin polymers or foreign matter that is not removed in the regeneration purification step (Management, Recycling and Reuse of Waste Composites, Vannessa Goodship, Woodhead Publishing, 2010). Examples include foreign polymers (e.g., PP, PET, PA in recycled polyethylene), trace metals (e.g., rust), contact media (e.g., oil, fat), inorganic impurities (e.g., dust, sand), organic impurities (e.g., ink, paint, adhesives), etc.

[0007] Therefore, there is still an urgent need for recycled materials with properties as close as possible to those of virgin resins. In particular, the object of the present invention is to provide PE-PCR materials that are superior to existing materials in terms of high product purity, low contaminant content, high homogeneity in terms of polyethylene content, improved mechanical properties such as ESCR performance, tear resistance, good tensile and impact properties, and good optical properties. Summary of the Invention

[0008] The object of the present invention is to provide a mixed plastic recycled polyethylene composition to address the above needs and shortcomings.

[0009] These objects are achieved by providing a mixed plastic recycled polyethylene composition that addresses the above-mentioned needs and drawbacks.

[0010] Therefore, the present invention provides a mixed plastic recycled polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190 ° C) of 0.1 to 1.5 g / 10 min; 938 to 985 kg / m 3 and containing more than 35% by weight of recycled polyethylene fraction (rPE);

[0011] Wherein, the mixed plastic recycled polyethylene composition has:

[0012] (a) the total amount of ethylene units (C2 units) is at least 95.0% by weight, as described in the experimental section below, by the d2-tetrachloroethylene soluble fraction 13 C-NMR measurements to determine;

[0013] (b) the total amount of continuous C3 units originating from polypropylene (PP) is from 0 to 3.0 wt. %, as described in the experimental part below, by quantification of the soluble fraction 13 to determine by C{1H}-NMR measurement; and

[0014] (c) an environmental stress crack resistance (ESCR) of at least 1000 hours to failure, preferably at least 2500 hours to failure, as determined by the Bell test according to IEC 60811-406, Method B, and as described in the Experimental Section below,

[0015] Wherein, the mixed plastic recycled polyethylene composition further comprises:

[0016] at least one virgin polyethylene component (B), optionally blended with carbon black, and

[0017] Optionally, a virgin polyethylene component (B1) different from the virgin polyethylene component (B), optionally blended with carbon black,

[0018] wherein the mixed plastic recycled polyethylene composition has a tear resistance of at least 24 N / mm, measured according to BS 6469 section 99.1.

[0019] The above-mentioned recycled polyethylene fraction (rPE) can be obtained by or through a process for regenerating a mixed plastics regrind stream, the process comprising the steps of:

[0020] a) providing a mixed plastic recycled material stream (A);

[0021] b) screening the mixed plastic recycle stream (A) to produce a screened mixed plastic recycle stream (B) having only items having a longest dimension in the range of 30 to 400 mm;

[0022] c) sorting the screened mixed plastic recycled material stream (B) by one or more sorting systems equipped with near infrared (NIR) and optical sensors, wherein the screened mixed plastic recycled material stream (B) is sorted at least according to polymer type and color to generate a sorted polyethylene recycled material stream (CM) of mixed color or other colors (e.g., natural color and white), which is subjected to step d) and subsequent steps separately;

[0023] d) crushing the sorted polyethylene recycled material stream (CM) to form a flake polyethylene recycled material stream (D);

[0024] e) washing the flaky polyethylene regeneration stream (D) with a first aqueous washing solution (W1) without input of thermal energy, thereby producing a first suspended polyethylene regeneration stream (E);

[0025] f) removing at least a portion of the first aqueous washing solution (W1) from the first suspended polyethylene regeneration stream (E) to obtain a first washed polyethylene regeneration stream (F);

[0026] g) washing the first washed polyethylene regeneration stream (F) with a second aqueous washing solution (W2) to produce a second suspended polyethylene regeneration stream (G), wherein sufficient thermal energy is introduced into the second suspended polyethylene regeneration stream (G) to provide a temperature in the range of 65 to 95° C. during washing;

[0027] h) removing the second aqueous wash solution (W2) and any material not floating on the surface of the second aqueous wash solution from the second suspended polyethylene regeneration stream (G) to obtain a second washed polyethylene regeneration stream (H);

[0028] i) drying the second washed polyethylene regeneration stream (H) to obtain a dried polyethylene regeneration stream (I);

[0029] j) optionally, separating the dried polyethylene regeneration stream (I) into a light fraction and a heavy fraction polyethylene regeneration stream (J) by air separation;

[0030] k) optionally screening the polyethylene regeneration stream;

[0031] l) optionally, further sorting the heavy fraction polyethylene recycled stream (J) by one or more optical sorters, or, in the absence of step j), sorting the dried polyethylene recycled stream (I) to sort out one or more target polyethylenes by removing any flakes containing materials other than the one or more target polyethylenes to obtain a purified polyethylene recycled stream (K);

[0032] m) optionally melt-extruding, preferably pelletizing, the purified polyethylene regenerated stream (K), preferably with the addition of additives (Ad) in the molten state, to form an extruded, preferably pelletized, recycled polyethylene product (L); and

[0033] n) optionally aerating the recycled polyethylene product (L) or, in the absence of step l), the purified polyethylene regeneration stream (K) to remove volatile organic compounds, thereby producing an aerated recycled polyethylene product (M), which can be an aerated extruded, preferably granular, recycled polyethylene product (M1) or an aerated recycled polyethylene flake (M2),

[0034] The order of steps n) and m) can be interchanged, so that the purified polyethylene regeneration stream (K) is first aerated to form aerated recycled polyethylene sheets (M2), which are then extruded, preferably with the additive (Ad) added in a molten state, to form an extruded, preferably granular, aerated recycled polyethylene product (M3), which is the above-mentioned recycled polyethylene fraction (rPE).

[0035] The present invention also relates to a method for preparing the above-mentioned mixed plastic recycled polyethylene composition, comprising the steps of melting, blending and extruding a recycled polyethylene fraction (rPE), at least one virgin high-density polyethylene component (B) and an optional virgin polyethylene component (B1) in an extruder, with the screw speed not exceeding 400 rpm, preferably not exceeding 350 rpm.

[0036] The present invention also relates to a mixed plastic recycled polyethylene composition, which can be obtained by or by a method comprising the following steps: melting, blending and extruding at least 35.0% by weight of a recycled polyethylene fraction (rPE) and at least 20% by weight of a virgin polyethylene fraction in an extruder at a screw speed of not more than 400 rpm, preferably not more than 350 rpm, wherein the virgin polyethylene fraction is selected from at least one virgin polyethylene component (B) optionally blended with carbon black and a virgin polyethylene component (B1) optionally blended with carbon black different from the virgin polyethylene component (B).

[0037] The present invention also relates to an article, preferably a power cable sheathing material made from the above mixed plastic recycled polyethylene composition, wherein the mixed plastic recycled polyethylene composition accounts for at least 85% by weight of the total composition used to make the article.

[0038] The present invention also relates to the use of the above mixed plastic recycled polyethylene composition in wire and cable applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The variation of the strain hardening factor (STF) with Eta 0.05 for the recycled compositions of the examples and the virgin polyethylene component (B) / (B1) alone is shown to indicate the processability of the samples at a given complex viscosity. As virgin polyethylene components, the polymers PE1, PE2, PE3, PE4, PE5, PE7, and PE8 listed in the Examples section were used. DETAILED DESCRIPTION

[0040] definition

[0041] For the purposes of this specification and the appended claims, the term "recycled stream" is used to refer to materials processed from post-consumer waste, as opposed to virgin polymers and / or materials. Post-consumer waste refers to items that have completed at least their first use cycle (or life cycle), i.e., items that have served their original purpose. The term "virgin" refers to materials and / or items that have been newly produced prior to their first use and have not been regenerated. The term "recycled material," as used herein, refers to materials that have been reprocessed from post-consumer waste or recycled streams.

[0042] A blend is a mixture of two or more components, at least one of which is a polymer. Typically, a blend can be prepared by mixing two or more components. Suitable mixing procedures are known in the art. If such a blend comprises virgin material, the virgin material is preferably polyethylene, comprising at least 90% by weight of a reactor-produced polyethylene material, and optionally carbon black. Virgin material refers to a polymeric material that has not yet been regenerated.

[0043] For the purposes of this specification and the appended claims, the term "mixed plastic recycled polyethylene composition" or "recycled polyethylene fraction (rPE)" refers to a polymeric material comprising mainly units derived from ethylene and containing other polymeric components of any nature. These other polymeric components may be derived, for example, from monomeric units of α-olefins (e.g. propylene, butene, octene, etc.), styrene derivatives (e.g. vinyl styrene), substituted and unsubstituted acrylates, substituted and unsubstituted methacrylates.

[0044] The other polymeric materials may be quantitatively 13 The C{1H}NMR measurement method was used to identify the presence of recycled polyethylene in mixed plastic compositions. 13 In the C{1H}NMR measurement method, the different units in the polymer chain can be distinguished and quantified. These units are ethylene units (C2 units) and units with 3, 4, 6 or 7 carbon atoms. Therefore, units with 2 carbon atoms (C2 units) can be distinguished in the NMR spectrum as individual C2 units and continuous C2 units, which indicates that the polymer material contains an ethylene-based polymer. The mixed plastic recycled polyethylene composition according to the present invention generally contains a small amount of propylene-based polymer components, especially a small amount of continuous C3 units derived from polypropylene (PP), which can be determined by performing a soluble fraction analysis as described in the experimental part below. 13 confirmed by C-NMR analysis.

[0045] The term "C2 fraction" refers to the recurring -[C2H4]- units derived from ethylene, which are present in a linear backbone and short chain branches, as determined by quantitative 13 C{ 1H} NMR spectroscopy, wherein the repeat represents at least two units.

[0046] The C2 fraction can be calculated as

[0047] Wt C2级分 =fC C2总 *100 / (fC C2总 +fC PP )

[0048] in

[0049] fC C2总 =(Iddg–ItwoB4)+(IstarB1*6)+(IstarB2*7)+(ItwoB4*9)+(IthreeB5*10)+((IstarB4plus-ItwoB4-IthreeB5)*7)+(I3s*3)

[0050] as well as

[0051] fC PP =Isαα*3

[0052] Details are given in the experimental section below.

[0053] Regeneration composition

[0054] The recycled compositions of the present invention may contain HDPE, LDPE, or LLDPE, homopolymer and copolymer polyethylene. Polyethylene can be characterized by analytical separation. One suitable method is chemical composition analysis by cross-fractionation chromatography (CFC). This method has been described and successfully implemented by Polymer Char, Valencia Technology Par, Gustave Eiffel 8, Paterna E-46980 Valencia, Spain. Chemical composition analysis by cross-fractionation chromatography (CFC) can be fractionated into a homopolymer fraction (HPF) and a copolymer fraction (CPF), as well as an isotactic polypropylene fraction (IPPF) that may be present. The homopolymer fraction (HPF) is a fraction containing polyethylene similar to homopolymer-HDPE. The copolymer fraction (CPF) is a fraction similar to polyethylene HDPE copolymers, but may also contain LDPE and LLDPE fractions, respectively. The isotactic polypropylene fraction (IPPF) contains isotactic polypropylene and is defined as the polymer fraction eluting at 104°C and above. The homopolymer fraction (HPF), the copolymer fraction (CPF) and, if present, the isotactic polypropylene fraction (IPPF) add up to 100% by weight. It goes without saying that 100% by weight refers to the material which is soluble in a cross fractionation chromatography (CFC) experiment.

[0055] In addition to chemical composition analysis by cross fractionation chromatography (CFC), the mixed plastic recycled polyethylene composition of the present invention also has the following characteristics: 13 The C2 fraction, as measured by C-NMR, contains at least 95.0% by weight, preferably at least 97.0% by weight. This percentage refers to the d2-tetrachloroethylene soluble portion used in the NMR experiment. The term "C2 fraction" refers to a polymer fraction derived from ethylene monomer units (i.e., not propylene monomer units).

[0056] The upper limit of the "C2 fraction" is 100% by weight.

[0057] Typically, other components may be present in the mixed plastic recycled polyethylene composition of the present invention, 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.

[0058] The mixed plastic recycled polyethylene composition according to the present invention has a melt flow rate (MFR5) of 0.1 to 10.0 g / 10 min (ISO 1133, 5.0 kg; 190° C.). The melt flow rate can be influenced by fractionating a post-consumer plastic waste stream, such as, but not limited to, waste streams from extended producer responsibility schemes (e.g., DSD in Germany), or waste streams sorted from municipal solid waste and separated into a number of pre-sorted fractions that are then recombined in an appropriate manner. Preferably, the MFR5 ranges from 0.5 to 5.0 g / 10 min, more preferably from 0.7 to 4.0 g / 10 min, and even more preferably from 1.0 to 3.0 g / 10 min.

[0059] The presence of carbon black can affect the density of the composition. The mixed plastic recycled polyethylene composition according to the present invention may contain carbon black or pigment, preferably the carbon black content does not exceed 5% by weight, more preferably does not exceed 3% by weight. The lower limit of carbon black is preferably at least 1.0% by weight, more preferably at least 2.0% by weight.

[0060] The carbon black-containing mixed plastic recycled polyethylene composition according to the present invention has a carbon black content of 950 to 985 kg / m 3 , preferably 952 to 975 kg / m 3 , more preferably 954 to 972 kg / m 3 density.

[0061] The carbon black-free mixed plastic recycled polyethylene composition according to the present invention has a viscosity of 938 to 973 kg / m 3 , preferably 940 to 963 kg / m 3 , more preferably 942 to 960 kg / m3 The density of Eta 0.05 This means that the processability of the composition is improved compared to the pure virgin polyethylene component.

[0062] The mixed plastic recycled polyethylene composition of the present invention preferably has a White Spot Rating (WSR) of no greater than 5.0, more preferably no greater than 4.0, measured according to ISO 18553 and as described herein.

[0063] The mixed plastic recycled polyethylene composition of the present invention preferably has a tensile strain at break of at least 670%, more preferably at least 700%, as measured on a Class 5A sample according to ISO 527-2. In certain embodiments, the mixed plastic recycled polyethylene composition of the present invention may have a tensile strain at break of at least 750%. The mixed plastic recycled polyethylene composition of the present invention may preferably have a tensile strain at break of no more than 1200%.

[0064] The mixed plastic recycled polyethylene composition of the present invention preferably has a tear strength of at least 24 N / mm, more preferably at least 25 N / mm, even more preferably at least 26 N / mm, and still more preferably at least 26.3 N / mm, as measured according to BS 6469, Section 99.1. The mixed plastic recycled polyethylene composition of the present invention may also have a tear strength of at least 27.0 N / mm. Preferably, the mixed plastic recycled polyethylene composition of the present invention has a tear strength of no more than 50 N / mm.

[0065] The mixed plastic recycled polyethylene composition according to the present invention preferably has a Large Amplitude Oscillation Shear - Non-Linear Factor (LAOS-NLF) in the range of 2.0 to 4.0, more preferably in the range of 2.3 to 3.8, measured at 190° C. and 1000% strain as described in the experimental part,

[0066]

[0067] in

[0068] G1' is the first-order Fourier coefficient

[0069] G3' is the third-order Fourier coefficient.

[0070] LAOS-NLF is a rheological measure of the degree of long-chain branching, further indicating the nonlinear polymer structure. The higher the LAOS-NLF value, the higher the degree of long-chain branching.

[0071] The mixed plastic recycled polyethylene composition according to the present invention may preferably have a strain hardening modulus of 10 MPa or more, preferably 12 MPa or more, measured according to ISO 18488 and as described herein, and / or may have a Shore D hardness (15s) of at least 57, preferably at least 57.5, measured according to ISO 868 and as described in the experimental part below. The mixed plastic recycled polyethylene composition according to the present invention may preferably have a Shore D hardness (15s) of not more than 67.

[0072] The strain hardening modulus is a measure of resistance to slow crack growth, while the Shore D hardness is a measure of the hardness of a material.

[0073] The mixed plastic recycled composition of the present invention is 0.05 The strain hardening factor (STF) and the complex shear viscosity (Eta) preferably exhibit the following inequalities at an angular frequency of 0.05 rad / s within the range of 10,000 to 100,000 Pa·s: 0.05 ):

[0074] STF>0.0009*Eta 0.05 (Pa·s)+9.

[0075] Preferably, the relationship satisfies STF>0.0009*Eta 0.05 (Pa·s)+12, more preferably, the relationship satisfies STF>0.0009*Eta 0.05 (Pa·s)+14.

[0076] Preferably, the complex shear viscosity Eta 0.05 It is 19,000 to 80,000 Pa·s, more preferably 20,000 to 70,000 Pa·s.

[0077] At a given Eta 0.05 Under the same conditions, STF and Eta 0.05 The above relationship means that the processability of the composition is improved.

[0078] The mixed plastic recycled polyethylene composition according to the present invention comprises more than 35% by weight of recycled polyethylene fraction (rPE), which is preferably obtained from post-consumer recycled (PCR). Such PCR materials are typically obtained from consumer waste streams, such as waste streams originating from traditional collection systems, such as those implemented by the European Union (e.g., extended producer responsibility schemes, EPR schemes). PCR materials can also come from municipal solid waste outside of EPR collection systems.

[0079] The raw material for obtaining the recycled polyethylene fraction (rPE) used in the present invention can be selected from various fractions produced from municipal solid waste (MSW, also often referred to as residual waste, black box waste) to feedstock based on extended producer responsibility (EPR), for example, the ARA 402 fraction from Altstoff Recycling Austria or the DSD 329 fraction from German producer responsibility organizations (such as DSD-Duales System Holding, Interzero, Reclay).

[0080] Preferably, the mixed plastic recycled polyethylene composition according to the present invention comprises at least 40 wt%, more preferably at least 45 wt%, even more preferably at least 50 wt% of recycled polyethylene fraction (rPE).

[0081] The mixed plastic recycled polyethylene composition according to the present invention can be obtained by a method comprising the following steps or can be obtained by a method comprising the following steps: melting, blending and extruding at least 35% by weight of a recycled polyethylene fraction (rPE) as defined herein and at least 20% by weight of a virgin polyethylene component in an extruder at a screw speed not exceeding 400 rpm, preferably not exceeding 350 rpm, wherein the virgin polyethylene component is selected from at least one virgin polyethylene component (B) optionally mixed with carbon black, and a virgin polyethylene component (B1) optionally mixed with carbon black different from the virgin polyethylene component (B). According to a preferred embodiment, the mixed plastic recycled polyethylene composition comprises the recycled polyethylene fraction (rPE) and the at least one virgin polyethylene component (B) optionally mixed with carbon black, and does not comprise the virgin polyethylene component (B1).

[0082] According to the mixed plastic recycled polyethylene composition of the present invention, in addition to the recycled polyethylene fraction (rPE), at least one virgin polyethylene component (B) and the optional virgin polyethylene component (B1), other components may also be included, for example, based on the total weight of the composition, no more than 15% by weight of other polymer components or additives. Suitable additives are additives commonly used with polyolefins, such as stabilizers (e.g., antioxidants), metal scavengers and / or UV stabilizers, antistatic agents and utilization agents. The content of the additive in the composition may be 10% by weight or less, more preferably 9% by weight or less, more preferably 7% by weight or less. Carbon black or other pigments are not included in the definition of additives.

[0083] The steps of melting, blending and extruding may preferably be performed as described in WO 2021 / 122299 A1.

[0084] Recycled polyethylene fraction (rPE)

[0085] In the mixed plastic recycled polyethylene composition according to the present invention, the content of recycled polyethylene fraction (rPE) is at least 35 wt%, preferably at least 40 wt%, more preferably at least 45 wt%, based on the total weight of the final composition. In the mixed plastic recycled polyethylene composition according to the present invention, the content of recycled polyethylene fraction (rPE) is preferably not more than 80 wt%, more preferably not more than 75 wt%, even more preferably not more than 70 wt%, based on the total weight of the final composition.

[0086] The recycled polyethylene fraction (rPE) used in the present invention has a homopolymer fraction (HPF) content in the range of 73.0 to 95.0 wt. %, preferably in the range of 75.0 to 94.0 wt. %, more preferably in the range of 77.0 to 93.0 wt. %, even more preferably in the range of 79.0 to 92.0 wt. %, as determined according to chemical composition analysis performed by cross fractionation chromatography (CFC).

[0087] The recycled polyethylene fraction (rPE) used in the present invention also has a copolymer fraction (CPF) content in the range of 5.0 to 27.0 wt. %, preferably in the range of 6.0 to 25.0 wt. %, more preferably in the range of 7.0 to 23.0 wt. %, even more preferably in the range of 8.0 to 21.0 wt. %, as determined by chemical composition analysis cross fractionation chromatography (CFC).

[0088] The recycled polyethylene fraction (rPE) used in the present invention also has a total content of heavy metals selected from Cr, Cd, Hg and Pb of not more than 100 ppm, preferably not more than 80 ppm, more preferably not more than 50 ppm, relative to the total recycled polyethylene fraction, as determined by X-ray fluorescence (XRF) as described in the experimental part below.

[0089] In some embodiments, the recycled polyethylene fraction (rPE) used in the present invention may be a mixed color polyethylene recycled blend, which may have the following CIELAB color space (L*a*b*) measured according to DIN EN ISO 11664-4 as described in the experimental section below:

[0090] L* from 30.0 to 73.0;

[0091] a* from -10.0 to 25.0;

[0092] b* ranges from -5.0 to 20.0.

[0093] Preferably, the CIELAB color space (L*a*b*) is defined as:

[0094] L* from 32.0 to 71.0;

[0095] a* from -9.0 to 23.0;

[0096] b* ranges from -5.0 to 18.0.

[0097] More preferably, the CIELAB color space (L*a*b*) is defined as:

[0098] L* from 35.0 to 70.0;

[0099] a* from -7.0 to 20.0;

[0100] b* ranges from -5.0 to 15.0.

[0101] In some embodiments, the recycled polyethylene fraction (rPE) used in the present invention may be a natural color polyethylene recycled blend, which may have the following CIELAB color space (L*a*b*) measured according to DIN EN ISO 11664-4 as described in the experimental section below:

[0102] L* from 55 to 88;

[0103] a* from -7.0 to 3.0;

[0104] b* ranges from 0.0 to 30.0.

[0105] Preferably, the CIELAB color space (L*a*b*) is defined as:

[0106] L* from 75.0 to 86.0;

[0107] a* from -5.0 to 0.0;

[0108] b* ranges from 5.0 to 25.0.

[0109] More preferably, the CIELAB color space (L*a*b*) is defined as:

[0110] L* from 76.0 to 85.0;

[0111] a* from -4.0 to -0.1;

[0112] b* ranges from 6.0 to 22.0.

[0113] The recycled polyethylene fraction (rPE) used in the present invention preferably has a benzene content below the detection limit as determined by static headspace chromatography mass spectrometry (HS / GC-MS) at 100°C / 2h as described in the experimental part below.

[0114] The recycled polyethylene fraction (rPE) used in the present invention preferably has an odor (VDA 270-B3) of 5.0 or less, more preferably 4.0 or less. It should be noted that many commercial recycled grades that do not report odor are actually even worse because the odor test according to VDA 270 is prohibited due to the presence of harmful substances.

[0115] Regeneration method

[0116] The above objects can also be achieved by the above-mentioned method for regenerating a mixed plastic recycled material stream, which method comprises steps a) to n), wherein steps j) to n) are optional steps. In other words, the recycled polyethylene fraction (rPE) used in the present invention is preferably obtained by the above-mentioned method or preferred method.

[0117] As mentioned above, the presence of carbon black affects the density of virgin polyethylene.

[0118] Virgin polyethylene (B) / (B1)

[0119] As described above, the mixed plastic recycled polyethylene composition of the present invention further comprises at least one virgin polyethylene component (B) optionally blended with carbon black, and optionally a virgin polyethylene component (B1) different from the virgin polyethylene component (B) optionally blended with carbon black. The at least one virgin polyethylene component (B) or the virgin polyethylene component (B1) is preferably a high density or medium density component.

[0120] The at least one virgin polyethylene component (B) preferably has a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of 0.01 to 1.2 g / 10 min, more preferably 0.05 to 1.0 g / 10 min, and has a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of 920 to 970 kg / m 3 , preferably 920 to 955 kg / m 3 The density of the carbon black is 932 to 982 kg / m 3 , preferably 944 to 967 kg / m 3 density.

[0121] The mixed plastic recycled polyethylene composition according to the present invention may also preferably comprise a virgin polyethylene component (B1) different from the virgin polyethylene component (B), which has a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of 0.04 to 0.8 g / 10 min, more preferably 0.05 to 0.5 g / 10 min, and may have a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of 930 to 960 kg / m 3 , more preferably 935 to 955 kg / m 3 The density of the carbon black is 942 to 972 kg / m3 , more preferably 947 to 967 kg / m 3 density.

[0122] The at least one virgin polyethylene component (B) and / or the virgin polyethylene component (B1) may preferably comprise at least one bimodal polyethylene, and preferably comprise a polyethylene homopolymer and a polyethylene copolymer. In some cases, the at least one virgin polyethylene component (B) and / or the virgin polyethylene component (B1) may comprise a copolymer of ethylene and one or more comonomer units selected from α-olefins having 3 to 6 carbon atoms. They may comprise a copolymer of ethylene and 1-butene or a copolymer of ethylene and 1-hexene.

[0123] In this context, the term "bimodal" means that the polymer consists of two polyethylene fractions which have been prepared under different polymerization conditions, resulting in the two fractions having different (weight average) molecular weights and molecular weight distributions. The shape of the molecular weight distribution curve of such a bimodal polyethylene, i.e. the appearance of the curve of the polymer weight fractions as a function of their molecular weight, will show two maxima, or at least be significantly broadened compared to the curve of the individual fractions.

[0124] The bimodal polyethylene preferably comprises a polyethylene homopolymer and a polyethylene copolymer.

[0125] Ethylene homopolymer refers to a polymer formed essentially only from ethylene monomer units, that is, more than 99.9% by weight of ethylene. Since industrial ethylene contains trace amounts of other monomers, trace amounts of other monomers may obviously be present.

[0126] Ethylene copolymers are made of ethylene and at least one other α-olefin comonomer having at least 4 carbon atoms (e.g., C 4-20 The comonomer is preferably an α-olefin, particularly 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 / or 1-hexene are preferably used.

[0127] Methods for obtaining such polymers are familiar to those skilled in the art and are described, for example, in WO 2015 / 121161 A1.

[0128] The at least one virgin polyethylene component (B) may preferably have a complex viscosity (η ) at an angular frequency ω of 0.05 rad / s of 15,000 to 90,000 Pa.s, more preferably 16,000 to 80,000 Pa.s, even more preferably 17,000 to 70,000 Pa.s. 0.05); and a shear thinning factor (STF) (eta 0.05 / eta 300 ), which is defined as the complex viscosity eta at 190° C. in the frequency range of 0.01 to 600 rad / s according to ISO 6721-1 and 6721-10 0.05 with eta 300 The shear thinning factor (STF) indicates the processability of polyethylene materials.

[0129] The virgin polyethylene component (B1) may preferably have a complex viscosity (η ) at an angular frequency ω of 0.05 rad / s of 100,000 Pa.s to 280,000 Pa.s, preferably 120,000 Pa.s to 250,000 Pa.s, more preferably 140,000 Pa.s to 230,000 Pa.s. 0.05 ); and a shear thinning factor (STF) (eta 0.05 / eta 300 ), which is defined as the complex viscosity eta at 190° C. in the frequency range of 0.01 to 600 rad / s according to ISO 6721-1 and 6721-10 0.05 with eta 300 The ratio.

[0130] The at least one virgin polyethylene component (B) may preferably have a strain hardening modulus of 12 to 49 MPa, more preferably 14 to 45 MPa, most preferably 15 to 42 MPa.

[0131] The virgin polyethylene component (B1) may preferably have a strain hardening modulus of 40 to 130 MPa, more preferably 50 to 120 MPa, most preferably 70 to 110 MPa.

[0132] The strain hardening modulus reflects the slow crack growth resistance (Kurelec, L., Teeuwen, M., Schoffeleers, H. & Deblieck, R. Strain hardening modulus as a measure of environmental stress crack resistance (ESCR) of high density polyethylene. Polymer 46, 6369-6379, (2005)). Therefore, an increase in the strain hardening modulus of the virgin polyethylene component (B) and / or (B1) helps to improve the slow crack growth resistance of the final recycled polyethylene composition of the present invention.

[0133] As mentioned above, the mixed plastic recycled polyethylene composition of the present invention exhibits an environmental stress crack resistance (ESCR) of at least 1000 hours to failure, preferably at least 2500 hours to failure, according to the Bell test conducted according to IEC 60811-406 Method B and as described in the experimental section below. The mixed plastic recycled polyethylene composition of the present invention may preferably exhibit an ESCR of no more than 20,000 hours to failure.

[0134] Preferably, the mixed plastic recycled polyethylene composition according to the present invention comprises at least 20.0 wt.%, more preferably at least 25 wt.%, even more preferably at least 30 wt.% of the total amount of virgin polyethylene components as defined above. Preferably, the mixed plastic recycled polyethylene composition according to the present invention comprises no more than 60.0 wt.%, more preferably no more than 55 wt.%, even more preferably no more than 50 wt.% of the total amount of virgin polyethylene components as defined above.

[0135] In some embodiments, the mixed plastic recycled polyethylene composition according to the present invention may contain no more than 70% by weight of the recycled polyethylene fraction (rPE) defined above, and a density (ISO 1183) of no more than 942 kg / m 3 The at least one virgin polyethylene component (B) and / or the virgin high density polyethylene component (B1) are preferably selected from the group consisting of: polyethylene glycol, ... and polyethylene glycol. As shown in the inventive examples IE4 to IE8 given in the experimental part, this composition surprisingly shows improvements in stress and strain at break, impact strength and ESCR.

[0136] Products

[0137] The present invention also relates to an article, preferably a jacketing material for a power cable or an optical cable, 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, preferably at least 88% by weight, more preferably at least 90% by weight of the total composition used to make the article.

[0138] use

[0139] The present invention also relates to the use of the mixed plastic recycled polyethylene composition according to the invention for wire and cable applications.

[0140] The mixed plastic recycled polyethylene composition according to the present invention is characterized by: higher purity in terms of isolated and continuous C3 units; improved ESCR (Bell test) performance; higher strain / stress at break performance; higher tear resistance; higher Charpy notched impact strength (NIS); high tensile modulus and improved strain hardening modulus; and lower white spot ratings, as discussed in detail in the Examples section below.

[0141] Measurement method

[0142] Unless otherwise defined, the following definitions of terms and assay methods apply to the above general description of the invention as well as to the following examples.

[0143] a) Melt flow rate

[0144] Melt flow rate (MFR) is measured according to ISO 1133 and is expressed in g / 10 min. The MFR is an indicator of polymer flowability and, therefore, processability. The higher the melt flow rate, the lower the polymer viscosity. The MFR is measured at 190°C under a load of 2.16 kg, 5.0 kg, or 21.6 kg.

[0145] b) Density

[0146] The density of non-foamed plastics is determined using ISO 1183-1:2012, Method A, the immersion method (Archimedean principle). 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 sample volume displaced by the liquid.

[0147] The test was carried out on PE (polyethylene) compression molded plates. The following parameters were used for the compression molding process.

[0148]

[0149] Conditioning time: 24 hours after compression molding (PE)

[0150] Test temperature: 23°C

[0151] Impregnation liquid: Isododecane

[0152] Buoyancy correction: None

[0153] c) C2 fraction determined by NMR spectroscopy and general microstructure including “continuous C3” as well as short chain branches

[0154] Use the 1 H and 13 Quantitative NMR spectra were recorded in solution on a Bruker Avance III 400 MHz NMR spectrometer operating at 400.15 and 100.62 MHz, respectively. 13 C{ 1 H}NMR spectra. All spectra were obtained using 13 Recordings were made at 125°C using a C-optimized 10 mm extended temperature probe, with nitrogen used for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) and chromium(III) acetylacetonate (Cr(acac)3) to yield a 65 mM relaxation agent solution 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 10 Hz. This setup was chosen primarily to achieve high precision and quantitative analysis, enabling accurate quantification of ethylene content. Standard single-pulse excitation was employed without NOE, along with optimized tilt angles, a 1 s recycle delay, and a two-stage WALTZ16 decoupling scheme {zhou07, busico07}. A total of 6144 (6k) transients were acquired for each spectrum.

[0155] Quantification was performed using a proprietary computer program 13 C{ 1 H NMR spectra were processed and integrated, and relevant quantitative properties were determined from the integrals. 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 various short-chain polyethylene branches (B1, B2, B4, B5, B6 plus) and polypropylene were observed {randall89, brandolini00}.

[0156] Characteristic signals corresponding to the presence of polyethylene were observed, including: 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 4 carbons (starB4plus 38.3 ppm), and the third carbon atom from the end of a saturated fatty chain (3s 32.2 ppm). The intensity of the ethylene backbone methine carbon (ddg), which includes a combination of polyethylene backbone carbon atoms (dd 30.0 ppm), γ-carbon atoms (g 29.6 ppm), 4s and threeB4 carbon atoms (to be compensated later), ranged from 30.9 ppm to 29.3 ppm, excluding Tββ in polypropylene. All of the mentioned signals were used to quantify the amount of C2-related carbons according to the following formula:

[0157] fC C2总计 =(Iddg–ItwoB4)+(IstarB1*6)+(IstarB2*7)+(ItwoB4*9)+I(threeB5*10)+((IstarB4plus-ItwoB4-IthreeB5)*7)+(I3s*3)

[0158] 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 content of PP-related carbon was quantified using the integral of Sαα at 46.6 ppm:

[0159] fC PP =Isαα*3

[0160] The weight percentages of C2 fraction and polypropylene can be quantified according to the following equations:

[0161] wt C2级分 =fC C2总计 *100 / (fC C2总计 +fC PP )

[0162] wt PP =fC PP *100 / (fC C2总计 +fC PP )

[0163] Characteristic signals corresponding to various short chain branches were observed and their weight percentages were quantified. Since the relevant branches would be α-olefins, the weight fraction of each branch was first quantified:

[0164] fwtC2=fC C2总计–((IstarB1*3)–(IstarB2*4)–(ItwoB4*6)–(IthreeB5*7)

[0165] fwtC3(isolated C3)=IstarB1*3

[0166] fwtC4=IstarB2*4

[0167] fwtC6=ItwoB4*6

[0168] fwtC7=IthreeB5*7

[0169] Normalizing all weight fractions gives the weight percentages of all relevant branches:

[0170] fsum wt％总计 =fwtC2+fwtC3+fwtC4+fwtC6+fwtC7+fC PP

[0171] wtC2 total = fwtC2*100 / fsum wt％总计

[0172] wtC3 total = fwtC3*100 / fsum wt％总计

[0173] wtC4 total = fwtC4*100 / fsum wt％总计

[0174] wtC6 total = fwtC6*100 / fsum wt％总计

[0175] wtC7 total = fwtC7*100 / fsum wt％总计

[0176] Assuming that B5 branches (generated solely by ethylene polymerized under high-pressure processes) are nearly constant in LDPE, we can estimate the LDPE content. We found that the average B5 content, quantified by C7, is 1.46 wt%. Based on this assumption, we can estimate the LDPE content to be within a certain range (approximately 20 wt% to 80 wt%), depending on the signal-to-noise ratio (SNR) of the three B5 signals:

[0177] wt% LDPE = wtC7 total * 100 / 1.46

[0178] References:

[0179] zhou07 Zhou,Z.,Kuemmerle,R.,Qiu,X.,Redwine,D.,Cong,R.,Taha,A.,Baugh,D.Winniford,B.,J.Mag.Reson.187(2007)225

[0180] busico07 Busico,V.,Carbonniere,P.,Cipullo,R.,Pellecchia,R.,Severn,J.,Talarico,G.,Macromol.Rapid Commun.2007,28,1128

[0181] singh09 Singh,G.,Kothari,A.,Gupta,V.,Polymer Testing 28 5(2009),475

[0182] randall89 J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.

[0183] brandolini00 AJBrandolini,DDHills,NMR Spectra of Polymers andPolymer Additives,Marcel Dekker Inc.,2000

[0184] d) Cross-fractionation chromatography

[0185] The chemical composition distribution and the determination of the molecular weight distribution and the corresponding average molecular weights (Mn, Mw and Mv) at a specific elution temperature (polymer crystallinity in solution) were determined by fully automated cross-fractionation chromatography (CFC) as described in Ortin A., Monrabal B., Sancho-Tello J., Macromol. Symp., 2007, 257, 13-28.

[0186] Cross-fractionation chromatography (TREFx SEC) was performed using a CFC instrument (PolymerChar, Valencia, Spain). Concentration was monitored using a quad-band IR5 infrared detector (PolymerChar, Valencia, Spain). The polymer was dissolved at 160°C for 150 minutes to a concentration of approximately 1 mg / ml.

[0187] To avoid injection of gels and polymers (such as PET and PA) that may not dissolve in TCB at 160°C, weighed samples were loaded into stainless steel mesh with MW 0.077 / D 0.05 mm.

[0188] After the sample was completely dissolved, a 0.5 ml aliquot was loaded onto a TREF column and stabilized for a period of time at 110° C. By applying a constant cooling rate of 0.1° C. / min, the polymer was crystallized and precipitated until 30° C. A discontinuous elution process was performed using the following temperature step: (35, 40, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 103, 106, 109, 112, 115, 117, 119, 121, 123, 125, 127, 130, 135, and 140).

[0189] For the second-dimension gel permeation chromatography (GPC) analysis, three PL Olexis columns and one Olexis Guard column from Agilent (Church Stretton, UK) were used as the stationary phase. 1,2,4-Trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) was used as the eluent, with a temperature of 150°C and a constant flow rate of 1 mL / min. The column set was calibrated using a universal calibration method (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards ranging from 0.5 kg / mol to 11,500 kg / mol. PS molecular weights were converted to PP equivalents using the following Mark Houwink constants.

[0190] K PS =19×10 -3 mL / g, α PS =0.655

[0191] K PP =19x 10 -3 mL / g, α PP =0.725

[0192] A third-order polynomial fit was used to fit the calibration data. Data processing was performed using the software provided by PolymerChar for the CFC instrument.

[0193] e) Environmental stress cracking resistance (Bell test)

[0194] The term ESCR (environmental stress crack resistance) refers to the ability of a polymer to resist crack formation when subjected to mechanical stress and to agents in the form of surfactants. ESCR is determined according to IEC 60811-406, Method B. The agent used is a 10 wt% aqueous solution of Igepal CO 630. The material is prepared according to the instructions for HDPE as follows: the material is pressed at 165°C to a thickness of 1.75-2.00 mm. The notch depth is 0.30-0.40 mm. In the results, a value of "0" indicates that the sample failed during preparation.

[0195] f) Tensile test

[0196] 5A dog bone specimens were prepared by die cutting from 2 mm thick die-stamped plaques according to ISO 527-2 / 5A. All specimens were conditioned at 23°C and 50% relative humidity for at least 16 hours before testing. Tensile properties were measured at 23°C and 50% relative humidity with an Alwetron R24, 1 kN load cell according to ISO 527-1 / 2. The tensile test speed was 50 mm / min, the clamping distance was 50 mm, and the gauge length was 20 mm. The 5A specimens were tested before aging, after aging at 100°C for 10 days (240 h), or after aging at 110°C for 14 days (336 h).

[0197] g) Flexural modulus

[0198] Flexural modulus was measured according to ISO 178, Method A (three-point bend test) on a sheet measuring 80 mm x 10 mm x 4 mm. In accordance with this standard, a test speed of 2 mm / min and a span of 16 x thickness were used. The test temperature was 23 ± 2°C. Compression molding was performed according to ISO 17855-2.

[0199] h) Impact strength (Charpy NIS)

[0200] Charpy notched impact strength (NIS) was measured according to ISO 179-1 / 1eA on 80 mm x 10 mm x 4 mm notched specimens (compression molded according to ISO 179-1 / 1eA). The test temperature was 0 ± 2°C, -20 ± 2°C, or -30 ± 2°C. Compression molding was performed according to ISO 17855-2.

[0201] i) CIELAB color space (L*a*b*)

[0202] Color values ​​and color differences were determined according to ISO 11664-4.

[0203] In the CIE L*a*b* uniform color space, color coordinates are: L*—lightness; a*—red / green coordinate, with +a* representing red and -a* representing green; and b*—yellow / blue coordinate, with +b* representing yellow and -b* representing blue. The L*, a*, and b* axes define the three-dimensional CIE color space. Measurements were performed using a standard Konica / Minolta colorimeter CM-3700A.

[0204] j) Heavy metal content

[0205] X-ray fluorescence (XRF) was used to determine the content of heavy metals such as Cr, Cd, Hg, and Pb.

[0206] The instrument used for XRF measurements was a Malvern Panalytical wavelength dispersive Zetium (2.4 kW) calibrated using Malvern Panalytical's polyolefin-based standards set (i.e., Toxel).

[0207] The analysis was performed under vacuum on a plate with a diameter of 40 mm and a thickness of 2 mm.

[0208] This method is used to determine the quantitative content of Cr, Cd, Hg and Pb in polyolefin matrix within the range specified in this standard.

[0209] k) Strain hardening (SH) modulus

[0210] The strain hardening test is a modified tensile test performed on specially prepared thin specimens at 80°C. Strain hardening modulus (MPa), <gp>, is calculated from the true strain-true stress curve; using the slope of the curve in the true strain (λ) region between 8 and 12.

[0211] The true strain λ is calculated from the length l (mm) and the gauge length l0 (mm), as shown in Formula 1.

[0212]

[0213] Where Δl is the increase in specimen length between gauge marks (mm). True stress σ 真 (MPa) Calculated according to Equation 2, assuming conservation of volume between gauge marks:

[0214] σ 真 =σ n λ (2)

[0215] where σ n is the engineering stress.

[0216] The Neo-Hookean constitutive model (Formula 3) is used to fit the true strain-true stress data, from which the true stress when 8 < λ < 12 is calculated. <gp>(MPa).

[0217]

[0218] where C is a mathematical parameter of the constitutive model, describing the yield stress extrapolated to λ = 0.

[0219] Initially measure five specimens. If <gp>If the coefficient of variation is greater than 2.5%, two additional specimens are measured. If the strain of the test rod occurs in the fixture, the test results are invalid.

[0220] According to the press parameters provided in Table 2 of ISO 1872-2, the PE material granules were pressed into sheets with a thickness of 0.30 mm.

[0221] After the sheet is press-formed, it is annealed to eliminate any orientation or thermal history and maintain isotropy. The sheet is annealed in an oven at (120±2)°C for 1 hour, then the chamber is closed and slowly cooled to room temperature. During this operation, the sheet can move freely.

[0222] Next, test pieces were punched out of the pressed sheets. The sample geometry used the modified ISO 37:1994, Type 3 (Figure 3).

[0223] The sample has a large clamping area to prevent the clamp from slipping. The dimensions are shown in Table 1.

[0224] Table 1: Dimensions of Type 3 of revised ISO 37:1994

[0225] size Size (mm) L Starting length between clamps 30.0+ / -0.5 l0 Gauge length 12.5+ / -0.1 l1 Prism length 16.0+ / -1.0 l3 Total length 70 R1 radius 10.0+ / -0.03 R2 radius 8.06+ / -0.03 b1 Prism width 4.0+ / -0.01 b2 Clamp width 20.0+ / -1.0 h thickness 0.30+0.05 / 0.30-0.03

[0226] The stamping process is carried out in such a way that no deformations, cracks or other irregularities appear on the test piece.

[0227] The thickness of the sample was measured at three points on the parallel area of ​​the sample; the smallest of these measured thickness values ​​was used for data processing.

[0228] 1. Perform the following steps on a universal tensile testing machine with a controlled temperature chamber and a non-contact extensometer:

[0229] 2. Before starting the test, place the test sample in a constant temperature box at (80±1)℃ for at least 30 minutes.

[0230] 3. Clamp the test piece at the upper side.

[0231] 4. Close the thermostat.

[0232] 5. After reaching the temperature of (80±1)°C, close the lower clamp.

[0233] 6. Allow the sample to equilibrate between the clamps for 1 minute before applying the load and starting the measurement.

[0234] 7. Apply a preload of 0.5 N at a speed of 5 mm / min.

[0235] 8. Extend the test sample along the main axis at a constant moving speed (20 mm / min) until the sample breaks.

[0236] During the test, the load on the sample was measured with a 200 N load cell, and the elongation was measured with a non-contact extensometer.

[0237] l) Carbon black dispersion and white point rating

[0238] The measurements were performed according to ISO 18553. Slices of approximately 15 μm in thickness were cut from six pellets using a Leica Histocore NANOCUT R and mounted on glass slides. The images of each complete slice were collected and stitched together using a microscope Olympus BX51 under transmitted light with a magnification of 100 times. The particles on each slice were automatically detected using the Olympus software Particle Inspector. For carbon black agglomerates and white spots, the grade used to provide the final classification was taken from ISO 18553 (e.g., grade 1 represents 1 particle with a diameter of 11-20 μm or 3 particles with a diameter of 5-10 μm). The final result is the average of six single measurements (slices).

[0239] m) Tear resistance

[0240] Tear resistance is measured on 1mm thick compression-molded sheet materials according to BS 6469, Section 99.1. The tear force is measured using a tensile testing machine using a notched test piece. Tear resistance is calculated by dividing the maximum force required to tear the test piece by its thickness.

[0241] n) Dynamic rheological measurement

[0242] Polymer melt characterization by dynamic shear measurements complies with ISO standards 6721-1 and 6721-10. Measurements were performed on an Anton Paar MCR501 stress-controlled rotational rheometer equipped with 25 mm parallel-plate geometry. Measurements were performed on compression-molded plaques under a nitrogen atmosphere, with strain set to the linear viscoelastic range. For PE, oscillatory shear tests were performed at 190°C, with an applied frequency range of 0.01 to 600 rad / s and a gap setting of 1.3 mm.

[0243] In dynamic shear experiments, the probe is subjected to uniform deformation under sinusoidally varying shear strain or shear stress (strain and stress control modes, respectively). In controlled strain experiments, the probe is subjected to a sinusoidal strain expressed as

[0244] (t)=γ0 sin(ωt) (1)

[0245] If the applied strain is in the linear viscoelastic range, the resulting sinusoidal stress response can be expressed as

[0246] (t)=σ0 sin(ωt+δ) (2)

[0247] in

[0248] σ0 and γ0 are the stress and strain amplitudes, respectively

[0249] ω is the angular frequency

[0250] δ is the phase shift (loss angle between applied strain and stress response)

[0251] t is time.

[0252] Dynamic test results are usually expressed in terms 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 heterogeneous component of the complex shear viscosity η", and the loss tangent tanδ, which can be expressed as follows:

[0253]

[0254] G * =G′+iG"[Pa] (5)

[0255] η * =η′-iη"[Pa.s] (6)

[0256]

[0257] The so-called shear thinning factor (STF) is determined as described in Equation 9.

[0258]

[0259] These values ​​were determined using the single-point interpolation procedure defined in the Rheoplus software. In cases where a given G* value was not experimentally achieved, the value was determined to be 10 by extrapolation using the same procedure as described above. In both cases (interpolation or extrapolation), the Rheoplus options "Interpolate y-values ​​to x-values ​​from parameter" and "logarithmic interpolation type" were used.

[0260] The tests were performed on compression-molded discs.

[0261] o) LAOS nonlinear viscoelastic ratio

[0262] The study of nonlinear viscoelastic behavior under shear flow is performed using the large amplitude oscillatory shear method. The method requires the application of a sinusoidal strain amplitude γ0 at a given time t and a given angular frequency ω. If the applied sinusoidal strain is high enough, a nonlinear response will occur. In this case, the stress σ is a function of the applied strain amplitude, time, and angular frequency. Under these conditions, the nonlinear stress response is still a periodic function; however, it can no longer be represented by a single harmonic sine wave. The stress caused by the linear viscoelastic response [1-3] can be represented by a Fourier series that includes the higher harmonic contributions:

[0263] σ(t,ω,γ0)=γ0·∑ n [G′ n (ω,γ0)·sin(nωt)+G″ n (ω,γ0)·cos(nωt)]

[0264] Where σ = stress response

[0265] t = time

[0266] ω = frequency

[0267] γ0=strain amplitude

[0268] n = number of harmonics

[0269] G' n = nth-order elastic Fourier coefficient

[0270] G” n = nth-order viscosity Fourier coefficient

[0271] The nonlinear viscoelastic response was analyzed using large amplitude oscillatory shear (LAOS). Time sweep measurements were performed using an Alpha Technologies RPA2000 rheometer and a standard double-cone die. During the measurement, the test chamber was sealed and a pressure of approximately 6 MPa was applied. LAOS tests were performed at a temperature of 190°C, an angular frequency of 0.628 rad / s, and a strain of 1000%. NLF (1000%)). To ensure that steady-state conditions are achieved, the nonlinear response is determined only after at least 20 cycles have been completed for each measurement. Large Amplitude Oscillatory Shear Nonlinearity Factor (LAOS) NLF ) is defined as:

[0272]

[0273] where G'1 = first-order elastic Fourier coefficient

[0274] G'3=third-order elastic Fourier coefficient

[0275] References:

[0276] 1.J.M.Dealy,K.F.Wissbrun,Melt Rheology and Its Role in PlasticsProcessing:Theory and Applications;edited by Van Nostrand Reinhold,New York(1990);

[0277] 2.S.Filipe,Non-Linear Rheology of Polymer Melts,AIP ConferenceProceedings 1152,pp.168-174(2009)3;

[0278] 3.M.Wilhelm,Macromol.Mat.Eng.287,83-105(2002);

[0279] 4.S.Filipe,K.Hofstadler,K.Klimke,A.T.Tran,Non-Linear RheologicalParameters for Characterisation of Molecular Structural Properties inPolyolefins,Proceedings of Annual European Rheology Conference,135(2010);

[0280] 5.S.Filipe,K.Klimke,A.T.Tran,J.Reussner,High ThroughputExperimentation:Novel Non-Linear Rheological Parameters for Quality Control,Novel Trends in Rheology IV,Zlin,Czech Republic(2011);

[0281] 6. K. Klimke, S. Filipe, ATTran, Non-linear rheological parameters for characterization of molecular structural properties in polyolefins, Proceedings of European Polymer Conference, Granada, Spain (2011).

[0282] p) Antioxidant content

[0283] Antioxidant content (chemicals such as 1010 (pentaerythritol tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate)) and 168 (tris(2,4-di-tert-butylphenyl)phosphite) was determined by high-performance liquid chromatography (HPLC) after extraction with ethyl acetate. Approximately 10 g of the sample was cryo-ground with the aid of liquid nitrogen. A portion of approximately 0.5 g of the ground sample was then extracted using ethyl acetate as the solvent. The extraction was carried out at 95°C for 90 minutes with constant stirring. After the mixture was allowed to cool to room temperature again, it was filtered and subjected to HPLC analysis for quantification of the antioxidant. The HPLC system was equipped with a C18 column for separation and a diode array detector (DAD) for detection.

[0284] q) Oxidation induction time OIT

[0285] The oxidation induction time (OIT) at 200°C was determined using a TA Instrument Q20 according to ISO 11357-6. The instrument was calibrated with indium and tin according to ISO 11357-1. The maximum temperature error after calibration was less than 0.1 K. Each polymer sample weighing 10 ± 2 mg (cylindrical, 5 mm diameter, 1 ± 0.1 mm thickness) was placed in an open aluminum crucible and heated in nitrogen (> 99.95 vol.% N2, < 5 ppm O2) at 20°C min -1 The rate of heating from 25℃ to 200℃ was 50mLmin -1 After standing for 5 minutes, the atmosphere was switched to pure oxygen (>99.95 vol. % O2) at a flow rate of 50 mL min -1 The sample was kept at a constant temperature and the heat released during 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.

[0286] r) Water content

[0287] The water content was determined as described in ISO 15512:2019, Method A - Anhydrous methanol extraction method. The test portion was extracted with anhydrous methanol, and the extracted water was determined using a coulometric Karl Fischer titrator.

[0288] s) Shore D hardness

[0289] Shore D hardness is measured according to ISO 868 on 4 mm thick compression-molded specimens. The Shore D hardness is measured after 1, 3, or 15 seconds of contact between the presser foot and the test specimen. The specimens are compression-molded according to ISO 17855-2 and milled to 80 x 10 x 4 mm.

[0290] t) Cable extrusion

[0291] Cable extrusion was performed on a Nokia-Maillefer cable production line. The extruder had five temperature zones at 170 / 175 / 180 / 190 / 190°C, and the extruder die had three zones at 210 / 210 / 210°C. The extruder screw was an Elise-designed barrier screw. The die was a semi-tubular design with a diameter of 5.9 mm, and the cable outer diameter was 5 mm. To investigate the extrusion properties, the compound was extruded onto a solid aluminum conductor with a diameter of 3 mm. The line speed was 75 m / min. The screen pressure and the extruder current consumption were recorded for each material.

[0292] u) Cable shrinkage

[0293] The shrinkage of the composition was determined using cable samples obtained from the cable extrusion process. Before cutting the sample, the cable was placed in a thermostatic chamber for at least 24 hours. The conditions in the thermostatic chamber were 23±2°C and 50±5% humidity. The sample was cut to 400 mm at least 2 m from the end of the cable. The sample was further placed in the thermostatic chamber for 24 hours and then placed in an oven at 100°C on a bed of talc for 24 hours. After removing the sample from the oven, it was allowed to cool to room temperature before measurement. The shrinkage was calculated according to the following formula:

[0294] [(L front – L back) / L front] x 100%, where L is the length.

[0295] v) Gel counting (OCS)

[0296] Cast films of recycled polyethylene fractions have been produced and optically inspected on a small laboratory cast film line equipped with a camera detector from Optical Control Systems.

[0297] The production line consists of a The extruder consisted of a screw with an aspect ratio of 25. The temperature profile of the five zones of the extruder was set at 190 / 200 / 210 / 210 / 200°C. 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 thickness of the produced film was 70 μm. During extrusion, the temperature of the cooling roller was set at 50°C. During the extrusion process, a 10 m 2 Gel particles and contaminants on the membrane are detected and counted. The camera has a resolution of 25 μm x 25 (on the membrane). Gel particles and contaminants are classified into four size classes (100-299 μm; 300-599 μm; 600-1000 μm; >1000 μm).

[0298] w) Crystallization and melting temperatures (Tc and Tm)

[0299] A TA Instruments Q2000 differential scanning calorimeter, calibrated with indium, zinc, and tin, was used and operated at a nitrogen flow rate of 50 mL / min. The thermal program used consisted of a first heating step from 0°C to 180°C to eliminate previous thermal history, followed by a cooling rate of 10°C / min. Melting behavior was captured by a second heating scan from 0°C to 180°C at a rate of 10°C / min. The crystallization and melting temperatures were taken as the peaks of the cooling and second heating scans, respectively.

[0300] x) Thermogravimetric analysis (TGA)

[0301] x-1) Carbon black content measured by TGA

[0302] Thermogravimetric analysis (TGA) experiments were performed using a Perkin Elmer TGA8000. Approximately 10-20 mg of material was placed in a platinum pan. The temperature was equilibrated at 50°C for 10 minutes, then raised to 900°C under nitrogen at a rate of 20°C / min. The temperature was then lowered to 300°C at a rate of 20°C / min, the gas was switched to oxygen, and the temperature was again raised to 900°C. The weight loss in this final step is attributed to the carbon black.

[0303] x-2) Ash content measured by TGA

[0304] Inorganic residues were measured by TGA using a Perkin Elmer TGA8000 according to DIN ISO 1172:1996. 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 under nitrogen at a rate of 20°C / min. Ash content was estimated as weight percent at 850°C.

[0305] y) Odor (VDA270-B3)

[0306] VDA 270 is used to determine the odor characteristics of automotive interior materials. In this study, odor was measured according to VDA 270 (2018), variant B3. Each assessor evaluated the odor of the corresponding sample according to the VDA 270 scale after opening the can lid as little as possible. The six-point scale consists of the following: 1: Not noticeable; 2: Noticeable, not disturbing; 3: Clearly noticeable, but not disturbing; 4: Disturbing; 5: Strongly disturbing; 6: Unacceptable. Assessors remained calm during the evaluation and were not allowed to bias each other by discussing individual results during the test. They were also not allowed to adjust their evaluation after testing another sample. For statistical reasons (and to comply with VDA 270), assessors were required to use the entire procedure in their evaluation. Therefore, the odor rating was based on the average of all individual evaluations and rounded to the nearest whole number.

[0307] z) Headspace gas chromatography / mass spectrometry (HS-GC-MS)

[0308] The determination of benzene and limonene is based on the static headspace (HS) method. The analysis uses a HS sampler combined with a gas chromatograph (GC) and a mass spectrometer (MS) for screening.

[0309] Samples were delivered to the laboratory in sealed aluminized polyethylene (PE) bags. Prior to analysis, samples were cryo-ground, and 2.000 ± 0.100 g of sample was weighed and placed in a 20 ml HS vial, which was then sealed. Each sample was measured in duplicate.

[0310] 1.1 HS / GC / MS parameters

[0311] HS parameters (Agilent G1888 headspace sampler)

[0312]

[0313] Slight shaking

[0314] GC parameters (Agilent 7890A GC system)

[0315]

[0316]

[0317] MS parameters (Agilent 5975C inert XL MSD)

[0318] Collection method: Scan

[0319] Scan parameters:

[0320] Low quality: 20

[0321] High quality: 200

[0322] Threshold: 10

[0323] · Software / Data Evaluation

[0324] MSD ChemStation E.02.02.1431

[0325] MassHunter GC / MS Acquisition Software B.07.05.2479

[0326] AMDIS GC / MS Analysis Version 2.71

[0327] NIST / EPA / NIH Mass Spectral Library (2011 Edition)

[0328] NIST Mass Spectral Search Program Version 2.0g

[0329] · AMDIS Deconvolution Parameters

[0330]

[0331]

[0332] · MSD ChemStation Integration Parameters

[0333]

[0334] In this study, the expression "below the detection limit (<LOD)" describes the situation where the match factor of the peak in the sample run is below 80 (AMDIS) or the signal-to-noise ratio (Pk-pk S / N = corrected signal / Pk-pk noise, MSD ChemStation signal-to-noise ratio report) is below 3. The results only refer to the measured sample, measurement time, and applied parameters.

[0335] 1.2. Standard solution

[0336] For positive identification and comparison with the (lowest) odor detection threshold (ODT), benzene standard and limonene standard were used respectively (see Table 1).

[0337] For HS / GC / MS analysis, 5 μl of the corresponding standard was injected into a 20 ml HS vial, capped, and measured.

[0338] Assuming complete vaporization of the standard substance, the concentration of benzene (or limonene in another case) in HS c G is estimated as shown in the following table.

[0339] Calibration Standard and ODT

[0340] Analytes solvent <![CDATA[c G / mg m -3 ]]> Target ion (m / z) <![CDATA[(Minimum) ODT / mg·m -3 [1]]]> benzene Methanol 25 78 1.5 Limonene 2-Butanol 75 68 0.21

[0341] 1.3 Data Evaluation

[0342] By considering the content of the substance m G and available HS volume V G To calculate HS c G The concentration of the analyte in (Equation 1).

[0343]

[0344] To estimate the concentration of the analyte in the HS above the polymer sample, the response factor (Rf) from the single-point calibration is required (Equation 2). The peak area of ​​the analyte can be obtained by integrating the extracted ion chromatogram (EIC). The corresponding target ions are listed in Equation 2.

[0345]

[0346] Calculate the analyte concentration in the HS above the polymer sample by multiplying the response factor by the EIC peak area of ​​the sample (Formula 3).

[0347]

[0348] In addition, the odor relevance of the analyte in the HS above the polymer sample can be assessed by the odor activity value (OAV). Compare this to the (lowest) odor detection threshold (ODT) found in the literature (Equation 4) [1]. Values ​​greater than 1 indicate a high correlation between the analyte and the odor at a given HS temperature.

[0349]

[0350] 1.4 Considerations and Limitations

[0351] It has to be taken into account that the ODT of some substances is below the limit of detection (LOD) of the method. Therefore, components below the LOD may be missed, although they are still relevant to the overall odor.

[0352] OAV is based on the assumption that HS parameters correlate with the measurement conditions of the ODT assay. This isn't always true, as a temperature setting of 100°C isn't always used in such experiments, so its practical value is limited. Nevertheless, this method can at least provide an indication of the odor relevance of a defined marker substance.

[0353] Taking into account all mentioned assumptions and limitations, the concentration and odor activity values ​​determined in the HS above the samples can only be regarded as rough estimates.

[0354] 1.5 References

[0355] [1]Van Gemert LJ, Odor Thresholds: Compilations of odor threshold values ​​in air, water and other media, Utrecht, Oliemans Punter&Partners BV, 2011.

[0356] Example

[0357] The following polyethylene materials were used to prepare the recycled compositions studied below:

[0358] Recycled polyethylene fraction (rPE)

[0359] The raw material for rPE1 comes from the mixed plastic fraction sorted from municipal solid waste (MSW) in Greece and Poland, while the raw material for rPE2 mainly comes from separately collected plastic waste.

[0360] The above-mentioned post-consumer waste raw materials were used to produce rPE1 and rPE2 by the following recycling method. The raw materials of rPE1 and rPE2 were respectively subjected to the recycling method comprising the following steps:

[0361] a) Provide bales of post-consumer plastic waste feedstock;

[0362] b) screening the material to remove the undersize fraction (and, if necessary, the oversize fraction),

[0363] c) HDPE natural color and mixed color fractions were sorted by near infrared (NIR) and optical sensors.

[0364] d) The HDPE natural color fraction and the mixed color fraction are ground, cleaned in an alkaline aqueous solution with various detergents, and then dried, air-sorted, and screened. The resulting HDPE mixed color flakes are further processed in steps e) and f) to produce rPE1; while the resulting HDPE natural color flakes are further processed in steps e) and f) to produce rPE2.

[0365] e) further sorting the resulting plastic flake material to eliminate non-polyolefin flakes;

[0366] f) extruding the material in the presence of a stabilizer and producing the HDPE blend according to the invention in the form of pellets;

[0367] For comparison purposes, a commercial product of HDPE regrind (rPE3) was provided. The product was made from post-consumer waste (PCW) consisting primarily of pre-sorted community waste.

[0368] Recycled polyethylene fraction rPE1

[0369] rPE1 has a mass of 961.5 kg / m 3 The density, MFR2 of 0.39g / 10min, MFR5 of 1.69g / 10min, and continuous C3 unit (PP) content of 1.45wt% were quantitatively 13 The soluble fraction was measured by C{1H}-NMR.

[0370] Recycled polyethylene fraction rPE2

[0371] rPE2 has a mass of 958.1 kg / m 3 The density, MFR2 of 0.55g / 10min, MFR5 of 1.38g / 10min, and continuous C3 unit (PP) content of 0.1wt% were quantitatively 13 The soluble fraction was measured by C{1H}-NMR.

[0372] Recycled polyethylene fraction rPE3

[0373] rPE3 has a mass of 957.0 kg / m 3 The density, MFR2 of 0.32g / 10min, MFR5 of 2.73g / 10min, and continuous C3 unit (PP) content of 6.94wt% were quantitatively 13 The soluble fraction was measured by C{1H}-NMR.

[0374] Recycled polyethylene fraction rPE4

[0375] rPE3 has a mass of 950.7 kg / m 3 The density, MFR2 of 0.91g / 10min, MFR5 of 4.23g / 10min, and continuous C3 unit (PP) content of 25.07wt% were quantitatively 13 The soluble fraction was measured by C{1H}-NMR.

[0376] Virgin polyethylene (component (B) or (B1))

[0377] PE1

[0378] PE1 is a high-density polyethylene containing carbon black, which has a 3 density, MFR2 of 0.5g / 10min, MFR5 of 1.85g / 10min, STF value of 31.99 and eta of 26074Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name HE6062.

[0379] PE2

[0380] PE2 is a natural color high density polyethylene with a density of 945.8 kg / m 3 density, MFR2 of 0.55 g / 10 min, MFR5 of 2.04 g / 10 min, STF value of 28.81 and eta of 21897 Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name HE6063.

[0381] PE3

[0382] PE3 is a natural color medium density polyethylene with a 3 density, MFR2 of 0.7 g / 10 min, MFR5 of 3.0 g / 10 min, STF value of 26.42 and eta of 21583 Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name ME6053.

[0383] PE4

[0384] PE4 is a natural color linear low density polyethylene with a hardness of 924.8 kg / m 3 density, MFR2 of 0.84 g / 10 min, MFR5 of 3.38 g / 10 min, STF value of 29.49 and eta of 17695 Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name LE8706.

[0385] PE5

[0386] PE5 is a natural color medium density polyethylene with a hardness of 932.3 kg / m 3 density, MFR2 of 0.24 g / 10 min, MFR5 of 0.9 g / 10 min, STF value of 65.98 and eta of 61889 Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name FB2310.

[0387] PE6

[0388] PE6 is a natural color high density polyethylene with a density of 949.6 kg / m 3 density, MFR2 of 0.05 g / 10 min, MFR5 of 0.25 g / 10 min, STF value of 136.82 and eta of 175270 Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name HE3493-LS-H.

[0389] PE7

[0390] PE7 is a natural color high density polyethylene with a density of 956.9 kg / m 3 density, MFR2 of 0.3g / 10min, MFR5 of 1.17g / 10min, STF value of 40.75 and eta of 37364Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name BB2581.

[0391] PE8

[0392] PE8 is a natural color high density polyethylene with a density of 954 kg / m 3 density, MFR2 of 0.3g / 10min, STF value of 43.80 and eta of 39948Pa·s 0.05 It is commercially available from Borealis AG (Vienna) under the product name BB2541.

[0393] The properties of the recycled materials (rPE1-3) and virgin polymers (PE1-8) are summarized in Table 1 below. "nd" in this table and the following tables means "not determined".

[0394] Table 1

[0395]

[0396]

[0397] Other ingredients

[0398] HE0880-A (Add1) is a HDPE-carbon black masterbatch containing 40% carbon black.

[0399] B225FF (Add2) is a processing and long-term heat stabilizer with a high phenolic antioxidant content, supplied by BASF, Ludwigshafen, Germany, at 50 wt% 168 and 50wt% 1010 mixed.

[0400] CEASIT AV / T (Add3) is granular calcium stearate supplied by Baerlocher AG.

[0401] The regrind fraction was mixed with virgin polyethylene on a Coperion W&P ZSK 32 mm co-rotating twin-screw extruder with a barrel temperature of up to 230°C and a screw speed of 300 rpm.

[0402] The obtained polyethylene recycled composition and the measurement results are shown in Table 2 below.

[0403] Table 2

[0404]

[0405]

[0406]

[0407] The results in Table 2 show the effect of the higher purity of the regrind fraction for IE1 and IE2 compared to CE1 and CE2, resulting in a superior combination of ESCR, stress and strain at break, tear resistance, and optical properties (white point rating) at comparable impact strength and stiffness.

[0408] Table 3

[0409]

[0410]

[0411]

[0412] The results in Table 3 show that the higher purity of the recycled fraction of IE3 combined with the addition of the virgin polyethylene component has the effect of further improving the impact strength, strain at break and optical properties (white point rating), while the ESCR remains very good.

[0413] Table 4

[0414]

[0415]

[0416] The results in Table 4 show the effect of a lower weight proportion of high purity regrind fraction and the addition of lower density virgin polyethylene on the improvement of stress and strain at break, impact strength and ESCR.

[0417] Figure 1 The strain hardening factor (STF) and Eta when the recycled composition and the virgin polyethylene component (B) / (B1) are used alone are shown. 0.05 to express the processability of the sample at a given complex viscosity.

[0418] For native PE, at an angular frequency of 0.05rad / s (Eta 0.05 ) complex shear viscosity in the range of 10,000 to 70,000 Pa·s and STF and Eta 0.05 The correlation between them is based on the following formula:

[0419] STF=0.0009*Eta 0.05 (Pa·s)+9.

[0420] Surprisingly, the mixed plastic recycled polyethylene composition prepared according to the present invention comprises a blend of a recycled polyethylene fraction (rPE) with at least one virgin polyethylene (B) and optionally (B1), at a given complex shear viscosity (Eta 0.05 ) shows a higher STF, i.e.

[0421] STF>0.0009*Eta 0.05 (Pa·s)+9.

[0422] This indicates that shear thinning is more pronounced than using the virgin PE component alone, and thus the mixed plastic recycled polyethylene composition of the present invention exhibits improved processability.< / gp> < / gp> < / gp>

Claims

1. A mixed plastic recycled polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of 0.1 to 1.5 g / 10 min; a flow rate (ISO 1133, 2.16 kg, 190° C.) of 938 to 985 kg / m 3 density (ISO 1183) and containing more than 35% by weight of recycled polyethylene fraction (rPE); in, The mixed plastic recycled polyethylene composition has: (a) a total amount of ethylene units (C2 units) of at least 95.0% by weight, as described herein, by the d2-tetrachloroethylene soluble fraction 13 C-NMR measurement; (b) the total amount of continuous C3 units derived from polypropylene (PP) is from 0 to 3.0 wt. %, as described herein, by quantification of the soluble fraction 13 to determine by C{1H}-NMR measurement; and (c) an environmental stress crack resistance (ESCR) of at least 1000 hours to failure, preferably at least 2500 hours to failure, as determined by the Bell test according to IEC 60811-406 Method B and as described herein, Wherein, the mixed plastic recycled polyethylene composition further comprises: at least one virgin polyethylene component (B), optionally blended with carbon black, and Optionally, a virgin polyethylene component (B1) different from the virgin polyethylene component (B), optionally blended with carbon black, The mixed plastic recycled polyethylene composition has a tear resistance of at least 24 N / mm measured according to BS 6469 Section 99.

1.

2. A mixed plastic recycled polyethylene composition, which can be obtained by or by a method comprising the following steps: melting, blending and extruding at least 35.0% by weight of a recycled polyethylene fraction (rPE) and at least 20% by weight of a virgin polyethylene fraction in an extruder at a screw speed not exceeding 400 rpm, wherein the virgin polyethylene fraction is selected from at least one virgin polyethylene component (B) optionally blended with carbon black and a virgin polyethylene component (B1) optionally blended with carbon black different from the virgin polyethylene component (B).

3. The mixed plastic recycled polyethylene composition according to claim 1 or 2, wherein the at least one virgin polyethylene component (B) has a melt flow rate (ISO 1133, 2.16 kg, 190 ° C) of 0.01 to 1.2 g / 10 min and a 3 density (ISO 1183), and / or The virgin polyethylene component (B1) has a melt flow rate (ISO 1133, 2.16 kg, 190°C) of 0.04 to 0.8 g / 10 min and a 3 density (ISO 1183).

4. A mixed plastic recycled polyethylene composition according to any one of the preceding claims having a strain hardening modulus of 10 MPa or more, preferably 12 MPa or more, measured according to ISO 18488 and as described herein, and / or Having a Shore D hardness (15s) of at least 57, measured according to ISO 868 and as described herein.

5. The mixed plastic recycled polyethylene composition of any one of the preceding claims having a strain hardening factor (STF) and a complex shear viscosity (Eta) at an angular frequency of 0.05 rad / s determined as described herein. 0.05 ): STF>0.0009*Eta 0.05 (Pa·s)+9 in, Eta 0.05 In the range of 10,000 to 100,000 Pa·s.

6. The mixed plastic recycled polyethylene composition of any preceding claim having a White Spot Rating (WSR) of not more than 5.0, measured according to ISO 18553 and as described herein.

7. The mixed plastic recycled polyethylene composition of any one of the preceding claims having a tensile strain at break of at least 670% measured on compression molded Grade 5A specimens according to ISO 527-2.

8. The mixed plastic recycled polyethylene composition according to any one of the preceding claims, wherein either of the at least one virgin polyethylene component (B) and the virgin polyethylene component (B1) is a bimodal polyethylene.

9. A mixed plastic recycled polyethylene composition according to any one of the preceding claims, comprising not more than 70 wt% of a recycled polyethylene fraction (rPE) as defined in claim 1, and said at least one virgin polyethylene component (B) and / or said virgin high density polyethylene component (B1) having a mass fraction of not more than 942 kg / m 3 density (ISO 1183).

10. The mixed plastic recycled polyethylene composition of any one of the preceding claims having a Large Amplitude Oscillatory Shear - Non-Linear Factor (LAOS-NLF) in the range of 2.0 to 4.0 measured at 190°C and 1000% strain as described herein, in G1' is the first-order Fourier coefficient G3' is the third-order Fourier coefficient.

11. A recycled polyethylene fraction (rPE) as defined in claim 1, obtainable by or through a process for regenerating a mixed plastic regrind stream, the process comprising the steps of: a) providing a mixed plastic recycled material stream (A); b) screening the mixed plastic recycle stream (A) to produce a screened mixed plastic recycle stream (B) having only items having a longest dimension in the range of 30 to 400 mm; c) sorting the screened mixed plastic recycled material stream (B) by one or more sorting systems equipped with near infrared (NIR) and optical sensors, wherein the screened mixed plastic recycled material stream (B) is sorted at least according to polymer type and color to generate a mixed color sorted or natural color or white sorted polyethylene recycled material stream (CM), which is subjected to step d) and subsequent steps separately; d) crushing the sorted polyethylene recycled material stream (CM) to form a flake polyethylene recycled material stream (D); e) washing the flaky polyethylene regeneration stream (D) with a first aqueous washing solution (W1) without input of thermal energy, thereby producing a first suspended polyethylene regeneration stream (E); f) removing at least a portion of the first aqueous washing solution (W1) from the first suspended polyethylene regeneration stream (E) to obtain a first washed polyethylene regeneration stream (F); g) washing the first washed polyethylene regeneration stream (F) with a second aqueous washing solution (W2) to produce a second suspended ethylene regeneration stream (G), wherein sufficient thermal energy is introduced into the second suspended polyethylene regeneration stream (G) to provide a temperature in the range of 65 to 95° C. during washing; h) removing the second aqueous wash solution (W2) and any material not floating on the surface of the second aqueous wash solution from the second suspended polyethylene regeneration stream (G) to obtain a second washed polyethylene regeneration stream (H); i) drying the second washed polyethylene regeneration stream (H) to obtain a dried polyethylene regeneration stream (I); j) optionally, separating the dried polyethylene regeneration stream (I) into a light fraction and a heavy fraction polyethylene regeneration stream (J) by air separation; k) optionally screening the polyethylene regeneration stream; l) optionally, further sorting the heavy fraction polyethylene recycled stream (J) by one or more optical sorters, or, in the absence of step j), sorting the dried polyethylene recycled stream (I) to sort out one or more target polyethylenes by removing any flakes containing materials other than the one or more target polyethylenes to obtain a purified polyethylene recycled stream (K); m) optionally melt-extruding, preferably pelletizing, the purified polyethylene regenerated stream (K), preferably with the addition of additives (Ad) in the molten state, to form an extruded, preferably pelletized, recycled polyethylene product (L); and n) optionally aerating the recycled polyethylene product (L) or, in the absence of step l), the purified polyethylene regeneration stream (K) to remove volatile organic compounds, thereby producing an aerated recycled polyethylene product (M), which can be an aerated extruded, preferably granular, recycled polyethylene product (M1) or an aerated recycled polyethylene flake (M2), The order of steps n) and m) can be interchanged, so that the purified polyethylene regeneration stream (K) is first aerated to form aerated recycled polyethylene sheets (M2), which are subsequently extruded, preferably with the addition of additives (Ad) in the molten state, to form an extruded, preferably granular, aerated recycled polyethylene product (M3), which is the recycled polyethylene fraction (rPE) defined in claim 1.

12. The recycled polyethylene fraction (rPE) according to claim 11, having a total amount of continuous C3 units derived from polypropylene (PP) in an amount not exceeding 1.0 wt%, as described herein by quantification of the soluble fraction. 13 This was determined by C{1H}-NMR measurement.

13. A method for preparing the mixed plastic recycled polyethylene composition according to any one of claims 1 to 10, comprising the following steps: The recycled polyethylene fraction (rPE), the at least one virgin polyethylene component (B) and optionally the virgin polyethylene component (B1) are melted, blended and extruded in an extruder at a screw speed not exceeding 400 rpm.

14. An article, preferably a jacketing material for a power cable or an optical cable, made from the mixed plastic recycled polyethylene composition according to any one of claims 1 to 10, wherein the mixed plastic recycled polyethylene composition accounts for at least 85 wt% of the total composition from which the article is made.

15. 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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