Compositions derived from post-consumer recycled materials with low crystallization temperatures

Abstract

Polyolefin compositions derived from post-consumer recycled (PCR) polyolefin (PO) based materials, wherein the polyolefin (PO) compositions exhibit balanced properties in terms of mechanical properties, low crystallization temperature, dimensional stability and processability.

Description

Technical Field

[0001] This invention relates to polyolefin compositions derived from post-consumer recycled (PCR) polyolefin (PO) based materials, the compositions having a good balance of mechanical properties, low crystallization temperature and processability. Background Technology

[0002] Polymer recycling is generally categorized into physical recycling (including mechanical and solvent-based recycling) and chemical recycling (including depolymerization, pyrolysis, and biodegradation). Before undertaking the appropriate recycling steps, waste undergoes pretreatment, which in particular includes waste pulverization and separation of different components. Polyolefins, especially polyethylene and polypropylene, are consumed in large quantities in a wide range of applications, including fibers, automotive parts, household components, and various finished products.

[0003] Polyethylene and polypropylene-based materials present a particular challenge due to their widespread use in packaging. Given the enormous volume of waste collected compared to the amount recycled into the waste logistics, intelligent reuse and mechanical recycling of plastic waste still hold significant potential.

[0004] Generally, the amount of polypropylene recycled in the market is a mixture of polypropylene (PP) and polyethylene (PE), especially for post-consumer waste streams. Furthermore, commercially recycled materials from post-consumer waste sources are often cross-contaminated with non-polyolefin materials such as polyethylene terephthalate, polyamides, polystyrene, or non-polymer materials such as wood, paper, glass, or aluminum. This cross-contamination significantly limits the end-use of the recycled stream, resulting in no profitable end-uses.

[0005] Furthermore, recycled polyolefin materials typically perform much worse than virgin materials unless the amount of recycled polyolefin added to the final compound is extremely low. For example, such materials often have limited impact strength and poor mechanical properties (e.g., brittleness), thus failing to meet customer requirements. Additionally, recycled polyolefins tend to be less processable than virgin materials. For a variety of applications, such as pipes, containers, automotive parts, or household goods, these limitations preclude the use of recycled materials in high-quality parts, meaning they will only be used in low-cost, less demanding applications such as construction or furniture. To improve the mechanical properties of these recycled materials, a relatively large amount of virgin material (derived from petroleum) is usually added.

[0006] What is particularly challenging is providing pipes, containers, automotive parts, or household products derived from recycled waste, in which a good balance is achieved in terms of mechanical properties, crystallization temperature, dimensional stability, and processability.

[0007] EP3260495 relates to components for domestic applications derived from recycled polyolefins. The compositions contain mineral fillers and / or reinforcing fillers. However, compositions containing mineral fillers require large quantities of pure polypropylene.

[0008] Therefore, there remains a need in the field to provide solutions for recycling polyolefins, especially for tubular materials that have a good balance of properties (e.g., mechanical properties, crystallization temperature, and processability) and contain a large amount of PO-based PCR material.

[0009] Surprisingly, the polyolefin compositions of the present invention, derived from PCR materials containing non-polyolefins and other contaminants, exhibit good mechanical properties, crystallization temperature, and processability. Attached Figure Description

[0010] Figure 1 The tensile modulus of the inventive example (white) and the comparative example (black) is shown as a function of the anisotropic shrinkage coefficient. Summary of the Invention

[0011] In its broadest aspect, the present invention provides a polyolefin composition that can be obtained by mixing the following components:

[0012] (a) 10 to 40% by weight of post-consumer recycled polyolefin-based material (PCR-PO), wherein the melt flow rate of said post-consumer recycled polyolefin-based material (PCR-PO) is 1 to 50 g / 10 min (as determined according to ISO 1133 at 2.16 kg and 230 °C).

[0013] (b) 10 to 35% by weight of a polypropylene composition (PP), wherein, based on the total weight of the polypropylene composition (PP), the C2 content of the polypropylene composition (PP) is less than 3.4% by weight, the polypropylene composition (PP) is selected from polypropylene homopolymer (h-PP1), polypropylene random copolymer (r-PP), and a mixture of polypropylene random copolymer (r-PP) and polypropylene homopolymer (h-PP2), wherein the melt flow rate of the polypropylene homopolymer (h-PP1) (determined according to ISO 1133 at 2.16 kg and 230 °C) is 10 to 40 g / 10 min;

[0014] (c) 30 to 55% by weight of inorganic fillers;

[0015] The amount of each component is based on the total weight of the polyolefin composition.

[0016] The polyolefin composition has a crystallization temperature Tc (determined according to ISO 11357) of less than 125°C and a flexural modulus (determined according to ISO 178) of more than 2000 MPa.

[0017] This invention is based on a surprising discovery that when post-consumer recycled polyolefin-based material (PCR-PO) is mixed with a polypropylene composition (PP) having a certain C2 content and a relatively high amount of inorganic filler, a polyolefin composition with a good balance of mechanical properties, crystallization temperature, and processability can be obtained. The inventors have surprisingly found that this polyolefin composition provides improvements in properties such as shrinkage and stiffness for articles obtained from said polyolefin composition.

[0018] The present invention also relates to injection-molded articles comprising polyolefin compositions, preferably pipes.

[0019] Furthermore, the present invention also relates to a method for manufacturing a polyolefin composition, the method comprising the step of mixing the following components to obtain the polyolefin composition:

[0020] (a) 10 to 40% by weight of post-consumer recycled polyolefin-based material (PCR-PO), wherein the melt flow rate of said post-consumer recycled polyolefin-based material (PCR-PO) is 1 to 50 g / 10 min (as determined according to ISO 1133 at 2.16 kg and 230 °C).

[0021] (b) 10 to 35% by weight of a polypropylene composition (PP), wherein, based on the total weight of the polypropylene composition (PP), the C2 content of the polypropylene composition (PP) is less than 3.4% by weight, the polypropylene composition (PP) is selected from polypropylene homopolymer (h-PP1), polypropylene random copolymer (r-PP), and a mixture of polypropylene random copolymer (r-PP) and polypropylene homopolymer (h-PP2), wherein the melt flow rate of the polypropylene homopolymer (h-PP1) (determined according to ISO 1133 at 2.16 kg and 230 °C) is 10 to 40 g / 10 min;

[0022] (c) 30 to 55% by weight of inorganic fillers;

[0023] The amount of each component is based on the total weight of the polyolefin composition. Preferably, the polyolefin composition has a crystallization temperature Tc (determined according to ISO 11357) of less than 125°C and a flexural modulus (determined according to ISO 178) of more than 2000 MPa.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention relates. While any methods and materials similar to or corresponding to those described herein may be used in practice to test the invention, preferred materials and methods are described herein. In recording and claiming protection for this invention, the following terms will be used according to the definitions listed below.

[0025] Unless otherwise expressly stated, the terms “a”, “an”, etc., refer to more than one.

[0026] For the purposes of this specification and the following claims, the term "recycled waste" is used to refer to materials recovered from post-consumer waste and industrial waste, rather than virgin polymers and / or materials.

[0027] "Post-consumer waste" refers to articles that have completed at least their first use cycle (or life cycle), i.e., articles that have achieved their primary purpose; while "industrial waste" refers to manufacturing waste that typically does not reach consumers. According to the invention, the waste stream is a consumer waste stream, which may originate from conventional collection systems, such as those used in the European Union. The post-consumer waste material is characterized by a limonene content of 0.10 to 500 ppm (determined by solid-phase microextraction (HS-SPME-GC-MS) using a standard additive method). For the purposes of this specification and the following claims, the term "polyolefin-based recycled waste material" refers to polyolefin materials derived from post-consumer waste and / or industrial waste, wherein the polyolefin-based recycled waste material comprises at least 88% by weight, preferably at least 92% by weight, more preferably at least 96% by weight of polyolefin (based on the total weight of the polyolefin-based recycled waste material). For the purposes of this specification and the following claims, the term "post-consumer recycled polyolefin-based material" (PCR-PO) refers to a polyolefin material derived from post-consumer waste, wherein the PCR-PO comprises at least 88% by weight, preferably at least 92% by weight, more preferably at least 96% by weight of polyolefin (based on the total weight of PCR-PO), and has completed at least one first-use cycle (or life cycle), i.e., has achieved its first purpose. Post-consumer recycled polypropylene-based material (PCR-PP) refers to a polypropylene material comprising at least 80% by weight of polypropylene (based on the total weight of PCR-PP), and has completed at least one first-use cycle (or life cycle), i.e., has achieved its first purpose. Similarly, post-consumer recycled polyethylene-based material (PCR-PE) refers to a polyethylene material comprising at least 65% by weight of polyethylene (based on the total weight of PCR-PE), and has completed at least one first-use cycle (or life cycle), i.e., has achieved its first purpose. Post-consumer recycled polyolefin-based material (PCR-PO) may also refer to a mixture of two or more different post-consumer recycled polyolefin-based materials (PCR-PO), preferably a mixture of PCR-PP and PCR-PE. The weight ratio of the PCR-PP / PCR-PE mixture can be PP:PE of 20:80 to 80:20.

[0028] It should be understood that the composition of PCR-PO can vary greatly, including both polyolefin homopolymers and polyolefin copolymers.

[0029] Typically, the PCR-PO of the present invention may have one or more of the following characteristics:

[0030] - Residual chalk content determined by the following methods;

[0031] - Residual talc content determined by the following methods;

[0032] - Metal residue content (determined by X-ray fluorescence (XRF));

[0033] - The amount of residual paper determined by the following methods;

[0034] - The amount of wood residue determined by the following methods;

[0035] - The total free fatty acid content ranged from 0.1 to 100 ppm, as measured by headspace solid-phase microextraction (HS-SPME-GC-MS).

[0036] Talc and chalk content:

[0037] According to the TGA following these steps:

[0038] Thermogravimetric analysis (TGA) experiments can be performed using a Perkin Elmer TGA 8000. Approximately 10–20 mg of material should be placed in a platinum dish. The temperature is equilibrated at 50 °C for 10 min, and then increased to 950 °C at a heating rate of 20 °C / min under nitrogen. The weight loss (WCO2) between approximately 550 °C and 700 °C is allocated to CO2 derived from CaCO3, thus the chalk content is assessed as follows:

[0039] Chalk content = 100 / 44 × WCO2

[0040] The temperature was then reduced to 300°C at a cooling rate of 20°C / min. The gas was then converted to oxygen, and the temperature was raised again to 900°C. The weight loss in this step is attributed to carbon black (Wcb). Knowing the contents of carbon black and chalk, the ash content, excluding chalk and carbon black, is calculated as follows:

[0041] Ash content = Ash residue – 56 / 44 × WCO2 – Wcb

[0042] The ash content was measured by weight percentage at 900°C in the first step under nitrogen atmosphere. The estimated ash content was the same as the talc content of the recovered material studied.

[0043] Quantities of paper and wood:

[0044] Paper and wood were tested using standard laboratory methods, including rolling, flotation, microscopy, and thermogravimetric analysis (TGA).

[0045] For the purposes of this invention, any polyolefin-based material containing at least 88% by weight of polyolefin (based on the total weight of the polyolefin-based material) and a limonene content of 0.0 to 500 ppm, preferably 0.10 to 500 ppm (determined by solid-phase microextraction (HS-SPME-GC-MS) using the standard addition method) should be considered as PCR-PO.

[0046] For the purposes of this invention, PCR-PO has at least one of the following:

[0047] - The limonene content is 0.05 to 500 ppm, preferably 0.10 to 500 ppm, more preferably 0.1 to 100 ppm, even more preferably 0.1 to 50 ppm, and particularly preferably 0.1 to 20 ppm (determined by solid-phase microextraction (HS-SPME-GC-MS) using the standard addition method);

[0048] - The polystyrene content is at most 6.0% by weight;

[0049] - The talc content is at most 3% by weight;

[0050] - The chalk content is at most 1.0% by weight;

[0051] - The polyamide content is at most 5.0% by weight;

[0052] - Fatty acid content (determined by solid-phase microextraction (HS-SPME-GC-MS) using the standard additive method) ranges from 1.0 to 100 ppm.

[0053] For the purposes of this specification and the following claims, the term "post-consumer recycled polyolefin-based material (PCR-PO)" further refers to a polymer material primarily comprising units derived from polyolefins (derived from ethylene, propylene, butene, octene, etc.), and other polymeric components of any nature. Such polymeric components may be derived, for example, monomeric units derived from styrene derivatives such as vinylstyrene, substituted and unsubstituted acrylates, and substituted and unsubstituted methacrylates. Other components are typically present, such as fillers, including organic and inorganic fillers such as talc, chalk, and carbon black, as well as further pigments (e.g., TiO2) and paper and cellulose.

[0054] Quantitative methods known in the art 13 C{ 1 ¹H NMR measurements are used to identify the polymeric material in the PCR-PO composition. This allows for the differentiation and quantification of different units within the polymer chain. These units include ethylene units (C2 units), units with 3, 4, and 6 carbon atoms, and units with 7 carbon atoms.

[0055] Therefore, units with three carbon atoms (C3 units) can be distinguished in nuclear magnetic resonance (NMR) spectra as independent C3 units (independent C3 units) and continuous C3 units (continuous C3 units), indicating that the polymer material contains propylene-based polymers. These continuous C3 units can also be identified as iPP units.

[0056] Units with 3, 4, 6, and 7 carbon atoms describe units in NMR spectra. These units are derived from short side chains or branches of two carbon atoms and one carbon atom (independent C3 unit), two carbon atoms (C4 unit), four carbon atoms (C6 unit), or five carbon atoms (C7 unit) in the polymer backbone.

[0057] Units with 3, 4, and 6 carbon atoms (individual C3, C4, and C6 units) can be derived from incorporated comonomers (propylene, 1-butene, and 1-hexene comonomers) or from short-chain branches formed by free radical polymerization.

[0058] The post-consumer recycled polyolefin-based materials used herein are commercially available. Suitable mixtures include various recycled materials from Mtm Plastics, branded under the names Purpolen, Dipolen, or Systalen, from Der Grüne Punkt. Other preferred post-consumer recycled polyolefin-based materials are polypropylene-rich recycled materials. Preferably, the polypropylene-rich recycled materials are obtained from recycled waste using plastic recycling methods known in the art. Such PP-rich recycled materials are commercially available, for example from Corepla (Italian consortium for the collection, recycling, and reuse of packaging plastic waste), ResourcePlastics (Blapton, Ontario), Kruschitz GmbH, Plastics and Recycling (AT), VogtPlastik GmbH (Germany), Mtm ​​Plastics GmbH (Germany), etc. Non-exhaustive examples of polypropylene-rich recycled materials include: PP, PP (Mtm Plastics GmbH), MOPRYLENE PC B-420White, MOPRYLENE PC B 440 (Morssinkhof Plastics, NL), SYSTALEN PP-C24000; Systalen PP-C44000; Systalen 13404GR 014, Systalen PP-C14900 GR000 (Der grüne Punkt, DE), Vision (Veolia) PPC BC 2006HS or PP MONO.

[0059] The term "virgin" refers to newly produced materials and / or objects that have not yet been recycled before their first use. For example, the term "recycled material" as used herein refers to materials that have been reprocessed from "recycled waste." Virgin and recycled materials can be easily distinguished based on the presence of contaminants such as limonene and / or fatty acids and / or paper and / or wood.

[0060] A mixture refers to a mixture of two or more components, wherein at least one component is polymerized. Typically, mixtures are prepared by mixing two or more components. Suitable mixing procedures are known in the art. For example, carbon black containing polyolefin homopolymer (CB-PO) is a mixture comprising polyolefin and carbon black.

[0061] Unless otherwise stated, "%" refers to weight%.

[0062] When referring to the composition and the weight percentage of its constituent components, it should be understood that, according to the invention, the total amount of the components does not exceed 100% (due to rounding ±1%). Detailed Implementation

[0063] According to the polyolefin composition of the present invention, the polyolefin composition can be obtained by mixing the following components:

[0064] (a) 10 to 40% by weight of post-consumer recycled polyolefin-based material (PCR-PO), wherein the melt flow rate of said post-consumer recycled polyolefin-based material (PCR-PO) is 1 to 50 g / 10 min (as determined according to ISO 1133 at 2.16 kg and 230 °C).

[0065] (b) 10 to 35% by weight of a polypropylene composition (PP), wherein, based on the total weight of the polypropylene composition (PP), the C2 content of the polypropylene composition (PP) is less than 3.4% by weight, the polypropylene composition (PP) is selected from polypropylene homopolymer (h-PP1), polypropylene random copolymer (r-PP), and a mixture of polypropylene random copolymer (r-PP) and polypropylene homopolymer (h-PP2), wherein the melt flow rate of the polypropylene homopolymer (h-PP1) (determined according to ISO 1133 at 2.16 kg and 230 °C) is 10 to 40 g / 10 min;

[0066] (c) 30 to 55% by weight of inorganic fillers;

[0067] The amount of each component is based on the total weight of the polyolefin composition.

[0068] The polyolefin composition has a crystallization temperature Tc (determined according to ISO 11357) of less than 125°C and a flexural modulus (determined according to ISO 178) of more than 2000 MPa.

[0069] It is important to understand that filler content refers to the total filler content based on the polyolefin composition. Therefore, when referring to fillers in a polyolefin composition, it may also include fillers that may be contained in, for example, post-consumer recycled polyolefin-based materials (PCR-PO) or polypropylene homopolymers (h-PP1).

[0070] According to the present invention, 100% by weight of the post-consumer recycled polyolefin-based material (PCR-PO) is derived from post-consumer waste, for example from conventional collection systems (curbside collection), such as those used in the European Union.

[0071] The post-consumer waste can be identified by its limonene content. Preferably, the limonene content of the post-consumer waste is 0.05 to 500 ppm, more preferably 0.10 to 500 ppm.

[0072] The present invention provides the polyolefin composition wherein the components are preferably mixed in the following amounts:

[0073] a) 20 to 38% by weight, preferably 25 to 35% by weight, more preferably 28 to 32% by weight of post-consumer recycled polyolefin-based material (PCR-PO);

[0074] b) 15 to 33% by weight, preferably 22 to 32% by weight, more preferably 25 to 30% by weight of a polypropylene composition (PP); and

[0075] c) 35 to 50% by weight, preferably 38 to 46% by weight, more preferably 39 to 45% by weight of inorganic filler;

[0076] The amount of each component is based on the total weight of the polyolefin composition.

[0077] Preferably, the post-consumer recycled polyolefin-based material (PCR-PO) is selected from post-consumer recycled polypropylene-based material (PCR-PP), post-consumer recycled polyethylene-based material (PCR-PE), and mixtures thereof, more preferably post-consumer recycled polypropylene-based material (PCR-PP).

[0078] In another preferred embodiment, based on the total weight of the post-consumer recycled polyolefin-based material (PCR-PO), the PCR-PO preferably comprises 80.0% to 99.0% by weight, more preferably 85.0% to 95.0% by weight, more preferably 87.0% to 93.0% by weight, and most preferably 88.0% to 92.0% by weight of propylene units (C3 units). According to the invention, these materials may refer to post-consumer recycled polypropylene-based material (PCR-PP). In this regard, ethylene units (C2 units) determined according to Appendix B of CRYSTEX QC method ISO 6427 are preferred. Without any theoretical constraints, it is presumed that when the C2 units of the PCR-PO material are determined according to Appendix B of CRYSTEX QC method ISO 6427, the vast majority of the remaining polyolefin units can be classified as propylene units (C3 units).

[0079] In a preferred embodiment, based on the total weight of the post-consumer recycled polyolefin-based material (PCR-PO), the PCR-PO preferably comprises 65.0 wt% to 99.0 wt%, more preferably 68.0 wt% to 96.0 wt%, more preferably 70.0 wt% to 92.0 wt%, and most preferably 72.0 wt% to 90.0 wt% of ethylene units (C2 units). According to the invention, these materials may refer to post-consumer recycled polyethylene-based material (PCR-PE).

[0080] In another preferred embodiment, the post-consumer recycled polyolefin-based material (PCR-PO) preferably comprises 35.0 wt% to less than 80.0 wt%, more preferably 38.0 wt% to 75.0 wt%, more preferably 40.0 wt% to 70.0 wt%, and most preferably 49.0 wt% to 60.0 wt% of propylene units (C3 units) (based on the total weight of PCR-PO), and 20.0 wt% to less than 65.0 wt%, more preferably 25.0 wt% to 62.0 wt%, more preferably 30.0 wt% to 60.0 wt%, and most preferably 40.0 wt% to 51.0 wt% of ethylene units (C2 units) (based on the total weight of PCR-PO). According to the invention, these materials may refer to a mixture of post-consumer recycled polyethylene-based material (PCR-PE) and post-consumer recycled polypropylene-based material (PCR-PP), i.e., a PCR-PP / PCR-PE mixture.

[0081] Preferably, the melt flow rate (ISO 1133, 2.16 kg, 230°C) of the post-consumer recycled polyolefin-based material (PCR-PO) is 2 to 40 g / 10 min, more preferably 3 to 35 g / 10 min, even more preferably 5 to 25 g / 10 min, and particularly preferably 8 to 20 g / 10 min. In a specific embodiment, the melt flow rate (ISO 1133, 2.16 kg, 230°C) of the post-consumer recycled polyolefin-based material (PCR-PO) is 1 to 10 g / 10 min, more preferably 2 to 8 g / 10 min, and even more preferably 3 to 7 g / 10 min. In another specific embodiment, the melt flow rate (ISO 1133, 2.16 kg, 230°C) of the post-consumer recycled polyolefin-based material (PCR-PO) is 20 to 50 g / 10 min, more preferably 25 to 45 g / 10 min, and even more preferably 30 to 40 g / 10 min.

[0082] Preferably, based on the total weight of the post-consumer recycled polyolefin-based material (PCR-PO), the ethylene units (C2 units) of the post-consumer recycled polyolefin-based material (PCR-PO) (determined according to Appendix B of CRYSTEX QC method ISO 6427) are 1 to 18% by weight, more preferably 2 to 15% by weight, even more preferably 3 to 12% by weight, and particularly preferably 4 to 10% by weight. According to the present invention, this post-consumer recycled polyolefin-based material (PCR-PO) refers to post-consumer recycled polypropylene-based material (PCR-PP).

[0083] Preferably, the tensile modulus (measured at 1 mm / min according to DIN EN ISO 527) of the post-consumer recycled polyolefin-based material (PCR-PO) is greater than 600 MPa, more preferably greater than 700 MPa, and even more preferably greater than 800 MPa. Furthermore, the tensile modulus (measured at 1 mm / min according to DIN EN ISO 527) of the post-consumer recycled polyolefin-based material (PCR-PO) is preferably from 600 to 2500 MPa, more preferably from 800 to 2000 MPa, more preferably from 900 to 1800 MPa, and particularly preferably from 1000 to 1600 MPa.

[0084] Preferably, the Charpy (determined according to ISO 179-1 / 1eA at 23±2°C) of the post-consumer recycled polyolefin-based material (PCR-PO) is 2.0 to 10.0 kJ / m³. 2 More preferably 2.5 to 9.0 kJ / m 2 More preferably 3.0 to 8.0 kJ / m 2 More preferably 3.5 to 7.0 kJ / m 2 The preferred value is 4.0 to 6.0 kJ / m³. 2 .

[0085] Preferably, the crystallization temperature Tc (determined according to ISO 11357) of the post-consumer recycled polyolefin-based material (PCR-PO) is 116 to 132°C, more preferably 118 to 130°C, even more preferably 120 to 128°C, and particularly preferably 122 to 126°C.

[0086] Preferably, the crystallization half-life (determined at 135°C according to ISO 11357-7) of the post-consumer recycled polyolefin-based material (PCR-PO) is 2.0 to 6.5 min, more preferably 2.5 to 5.0 min, even more preferably 3.0 to 4.5 min, and particularly preferably 3.4 to 4.2 min.

[0087] Preferably, the density of the post-consumer recycled polyolefin-based material (PCR-PO) (determined according to DIN EN ISO 1183) is 900 to 956 kg / m³. 3 More preferably 905 to 950 kg / m 3 More preferably 908 to 948 kg / m 3 The preferred strength is 910 to 945 kg / m³. 3 .

[0088] Preferably, the amount of the soluble fraction (SF, determined according to Appendix B of CRYSTEX QC method ISO 6427) of the post-consumer recycled polyolefin-based material (PCR-PO) relative to the total weight of PCR-PO ranges from 4.0 to 40.0% by weight, more preferably from 5.0 to 30.0% by weight, more preferably from 6.0 to 20.0% by weight, and particularly preferably from 7.0 to 15.0% by weight.

[0089] Preferably, the amount of the crystalline fraction (CF, determined according to Appendix B of CRYSTEX QC method ISO 6427) of the post-consumer recycled polyolefin-based material (PCR-PO) ranges from 60.0 to 96.0% by weight, more preferably from 70.0 to 95.0% by weight, more preferably from 80.0 to 94.0% by weight, and particularly preferably from 85.0 to 93.0% by weight (relative to the total weight of PCR-PO).

[0090] Preferably, the ethylene content (measured by Fourier Transform Infrared Spectroscopy (FTIR) during CRYSTEX analysis) of the soluble portion of the post-consumer recycled polyolefin-based material (PCR-PO) ranges from 15.0 to 90.0 wt%, more preferably from 20.0 to 60.0 wt%, even more preferably from 25.0 to 52.0 wt%, and particularly preferably from 26.0 to 35.0 wt%.

[0091] Preferably, the ethylene content (measured by Fourier Transform Infrared Spectroscopy (FTIR) during CRYSTEX analysis) of the crystalline portion of the post-consumer recycled polyolefin-based material (PCR-PO) ranges from 1.0 to 20.0 wt%, more preferably from 1.0 to 15.0 wt%, and even more preferably from 2.0 to 10.0 wt%.

[0092] Preferably, the intrinsic viscosity (measured in decahydronaphthalene at 135°C according to ISO 1628-1) of the soluble portion of the post-consumer recycled polyolefin-based material (PCR-PO) is in the range of 0.05 to 5.0 dl / g, more preferably 0.1 to 4.0 dl / g, even more preferably 0.5 to 3.0 dl / g, and particularly preferably 1.0 to 2.2 dl / g.

[0093] Preferably, the intrinsic viscosity (measured in decahydronaphthalene at 135°C according to ISO 1628-1) of the crystalline portion of the post-consumer recycled polyolefin-based material (PCR-PO) ranges from 0.1 to 5.0 dl / g, more preferably from 0.5 to 4.0 dl / g, even more preferably from 0.8 to 3.0 dl / g, and particularly preferably from 1.1 to 2.3 dl / g.

[0094] In one embodiment of the invention, the polyolefin composition comprises another post-consumer recycled polyolefin-based material (PCR-PO2), wherein the difference between PCR-PO2 and PCR-PO is at least in the melt flow rate (determined according to DIN EN ISO 1133 at 230°C / 2.16 kg).

[0095] Preferably, based on the total weight of the polypropylene composition (PP), the C2 content of the polypropylene composition (PP) is less than 3.2% by weight, more preferably less than 3.0% by weight, and particularly preferably less than 2.8% by weight. In this regard, the ethylene units (C2 units) are preferably determined according to Annex B of ISO 6427 using the CRYSTEX QC method.

[0096] In a preferred embodiment of the invention, the polypropylene composition (PP) is a polypropylene homopolymer (h-PP1). In this regard, it should be understood that the C2 content of the polypropylene homopolymer (h-PP1) is less than 0.5% by weight, preferably less than 0.1% by weight.

[0097] The crystallization temperature Tc of the polypropylene homopolymer (h-PP1) (determined according to ISO 11357) is preferably 90 to 128°C, more preferably 95 to 127°C, more preferably 100 to 126°C, more preferably 102 to 124°C, more preferably 104 to 122°C, and particularly preferably 105 to 120°C.

[0098] Preferably, the melt flow rate of the polypropylene homopolymer (h-PP1) (measured according to ISO 1133 at 2.16 kg and 230 °C) is 12 to 35 g / 10 min, more preferably 13 to 30 g / 10 min, even more preferably 14 to 28 g / 10 min, and particularly preferably 15 to 25 g / 10 min.

[0099] Preferably, the flexural modulus (determined according to ISO 178) of the polypropylene homopolymer (h-PP1) is 900 to 2500 MPa, more preferably 1000 to 2300 MPa, more preferably 1000 to 1800 MPa, more preferably 1100 to 1700 MPa, more preferably 1200 to 1650 MPa, and particularly preferably 1250 to 1600 MPa.

[0100] Preferably, the XCS content of the polypropylene homopolymer (h-PP1) (determined according to ISO 64279 at 23°C) is less than 5% by weight, more preferably less than 4% by weight, and particularly preferably less than 3% by weight.

[0101] Preferably, based on the total weight of the polypropylene homopolymer (h-PP1), the polypropylene homopolymer (h-PP1) contains less than 1% by weight, more preferably less than 0.4% by weight, and particularly preferably less than 0.3% by weight of talc.

[0102] In a preferred embodiment of the invention, the polypropylene composition (PP) is a random copolymer of polypropylene (r-PP) having a crystallization temperature Tc (determined according to ISO 11357) greater than 105 to 115°C, preferably 106 to 112°C, and particularly preferably 107 to 110°C.

[0103] In another preferred embodiment of the invention, the polypropylene composition (PP) is a mixture of a random copolymer of polypropylene (r-PP) and a homopolymer of polypropylene (h-PP2), wherein the crystallization temperature Tc (as determined according to ISO 11357) of the random copolymer of polypropylene (r-PP) is greater than 95 to 110°C, preferably 100 to 108°C, particularly preferably 102 to 106°C, and the crystallization temperature Tc (as determined according to ISO 11357) of the homopolymer of polypropylene (h-PP2) is greater than 115 to 140°C, preferably 120 to 135°C, particularly preferably 122 to 130°C.

[0104] Preferably, the flexural modulus (determined according to ISO 178) of the random copolymer of polypropylene (r-PP) is 400 to 1500 MPa, more preferably 500 to 1300 MPa, and particularly preferably 600 to 1100 MPa.

[0105] Preferably, the melt flow rate (ISO 1133, 2.16 kg, 230 °C) of the random copolymer of polypropylene (r-PP) is 1 to 40 g / 10 min, more preferably 2 to 30 g / 10 min, more preferably 3 to 25 g / 10 min, and particularly preferably 4 to 20 g / 10 min.

[0106] Preferably, the XCS content of the random copolymer of polypropylene (r-PP) (determined at 23°C according to ISO 64279) is less than 15% by weight, more preferably less than 12% by weight, and particularly preferably less than 10% by weight.

[0107] Preferably, based on the total weight of the polypropylene random copolymer (r-PP), the polypropylene random copolymer (r-PP) contains less than 1% by weight, more preferably less than 0.4% by weight, and particularly preferably less than 0.3% by weight of talc.

[0108] The polypropylene homopolymer (h-PP2) can be any known polypropylene homopolymer known in the art. Therefore, it can also correspond to the polypropylene homopolymer (h-PP1) as detailed above.

[0109] Preferably, the crystallization temperature Tc of the polypropylene homopolymer (h-PP2) (determined according to ISO 11357) is greater than 115 to 140°C, more preferably 120 to 135°C, and particularly preferably 122 to 130°C.

[0110] Preferably, the melt flow rate of the polypropylene homopolymer (h-PP2) (measured according to ISO 1133 at 2.16 kg and 230 °C) is 12 to 35 g / 10 min, more preferably 13 to 30 g / 10 min, even more preferably 14 to 28 g / 10 min, and particularly preferably 15 to 25 g / 10 min.

[0111] Preferably, the flexural modulus (determined according to ISO 178) of the polypropylene homopolymer (h-PP2) is 1000 to 1750 MPa, more preferably greater than 1700 to 2800 MPa, even more preferably 1750 to 2600 MPa, and particularly preferably 1800 to 2500 MPa.

[0112] Preferably, the XCS content of the polypropylene homopolymer (h-PP2) (determined at 23°C according to ISO 64279) is less than 5% by weight, more preferably less than 4% by weight, and particularly preferably less than 3% by weight.

[0113] Preferably, based on the total weight of the polypropylene homopolymer (h-PP2), the polypropylene homopolymer (h-PP2) contains 0.01 to 2.0% by weight, more preferably 0.1 to 1.5% by weight, and particularly preferably 0.3 to 1.0% by weight of talc.

[0114] In a preferred embodiment of the invention, the inorganic filler is calcium carbonate. Calcium carbonate can be provided from natural sources (ground (natural) calcium carbonate, GCC) and its synthetic forms. Typically, the natural form has a wide particle size range (e.g., from 0.5 to greater than 100 μm). The synthetic (precipitated) form typically falls within the nanoscale range (e.g., less than 100 nm). Preferably, when referring to calcium carbonate, it refers to chalk.

[0115] In a preferred embodiment of the invention, the crystallization temperature Tc (as determined according to ISO 11357) of the polyolefin composition is below 124°C. In another preferred embodiment of the invention, the crystallization temperature Tc (as determined according to ISO 11357) of the polyolefin composition is 118 to 125°C, more preferably 120 to 124°C, even more preferably 121 to 124°C, and particularly preferably 122 to 124°C.

[0116] Preferably, the flexural modulus of the polyolefin composition (determined according to ISO 178) is 2000 to 2500 MPa, more preferably 2020 to 2400 MPa, even more preferably 2050 to 2350 MPa, and particularly preferably 2100 to 2300 MPa.

[0117] Preferably, the melt flow rate of the polyolefin composition (measured according to ISO 1133 at 2.16 kg and 230 °C) is 9 to 35 g / 10 min, more preferably 10 to 30 g / 10 min, more preferably 11 to 28 g / 10 min, more preferably 12 to 25 g / 10 min, and particularly preferably 13 to 22 g / 10 min.

[0118] Preferably, the Charpy ratio of the polyolefin composition (determined according to ISO 179-1 / 1eA at 23±2°C) is 1.5 to 2.6 kJ / m³. 2 More preferably 1.9 to 2.4 kJ / m 2 The preferred value is 2.0 to 2.3 kJ / m³. 2 .

[0119] Preferably, the heat deflection temperature (HDT; determined according to ISO 1873-2 at 0.45 MPa) of the polyolefin composition is 85 to 108°C, more preferably 90 to 104°C, and particularly preferably greater than 95 to 100°C.

[0120] Preferably, the crystallization half-life of the polyolefin composition (determined at 135°C according to ISO 11357-7) is 2.3 to 7.0 min, more preferably 2.5 to 5.0 min, and particularly preferably 2.6 to 4.0 min.

[0121] Optionally, the polyolefin composition may also include a carrier. The carrier can be used for premixed additives, such as stabilizers, and introduced into the polyolefin composition. The carrier can be any suitable carrier known in the art. Preferably, the carrier is a polypropylene homopolymer-based carrier, wherein the melt flow rate (determined according to ISO 1133 at 2.16 kg, 230 °C) of the polypropylene homopolymer is 0.5 to 9.0 g / 10 min, more preferably 1.0 to 7.0 g / 10 min, more preferably 1.5 to 5.0 g / 10 min, particularly preferably 2.0 to 4.0 g / 10 min, and / or the density (determined according to DIN EN ISO 1183) is 890 to 920 kg / m³. 3 More preferably 895 to 915 kg / m 3 900 to 910 kg / m³ is particularly preferred. 3 The carrier may be present in the polyolefin composition in an amount of 0 to 3.0 wt%, preferably 0 to 2.5 wt%, and particularly preferably 0.5 to 2.0 wt%, based on the total amount of the polyolefin composition.

[0122] In a further aspect, the present invention relates to injection-molded articles comprising polyolefin compositions as defined herein, preferably tubing.

[0123] Preferably, the flow shrinkage (SH-inF; measured according to EN ISO 1873-2 at 60×60×2mm) of the injection molded article is less than 1.60%, more preferably less than 1.55%, and particularly preferably less than 1.52%.

[0124] Preferably, the cross-flow shrinkage (SH-crossF; measured according to ENISO 1873-2 at 60×60×2mm) of the injection molded article is less than 1.50%, more preferably less than 1.40%, even more preferably less than 1.30%, and particularly preferably less than 1.18%.

[0125] Preferably, the flow shrinkage (SH-inF; measured according to EN ISO 1873-2 at 60×60×2mm) of the injection molded article is 1.45 to 1.60%, more preferably 1.47 to 1.55%, and particularly preferably 1.49 to 1.54%.

[0126] Preferably, the cross-flow shrinkage (SH-crossF; measured according to ENISO 1873-2 at 60×60×2mm) of the injection molded article is 1.00 to 1.60%, more preferably 1.05 to 1.53%, and particularly preferably 1.06 to 1.3%.

[0127] Preferably, the anisotropic shrinkage coefficient (flow shrinkage SH-inF / crossflow shrinkage SH-crossF; measured according to EN ISO 1873-2 at 60×60×2 mm) of the injection-molded article is 1.38 or less, more preferably 1.37 or less, more preferably 1.36 or less, and more preferably 1.35 or less. Alternatively, the anisotropic shrinkage coefficient (flow shrinkage SH-inF / crossflow shrinkage SH-crossF; measured according to EN ISO 1873-2 at 60×60×2 mm) of the injection-molded article is preferably 1.00 to 1.38, more preferably 1.00 to 1.36, and more preferably 1.00 to 1.35. In some embodiments of the present invention, the anisotropic shrinkage coefficient (flow shrinkage SH-inF / crossflow shrinkage SH-crossF; measured according to EN ISO 1873-2 at 60×60×2 mm) of the injection-molded article is 1.00 to 1.10, more preferably 1.00 to 1.05.

[0128] In a specific embodiment of the present invention, the flow shrinkage rate (60×60×2mm) of the injection molded article is less than 1.55% and the crossflow shrinkage rate (60×60×2mm) is less than 1.18%.

[0129] All of the above-mentioned preferred aspects, definitions, and implementation methods also apply to injection molded products.

[0130] In a further aspect, the present invention relates to a method for manufacturing a polyolefin composition, the method comprising the step of mixing the following components to obtain the polyolefin composition:

[0131] (a) 10 to 40% by weight of post-consumer recycled polyolefin-based material (PCR-PO), wherein the melt flow rate of said post-consumer recycled polyolefin-based material (PCR-PO) is 1 to 50 g / 10 min (as determined according to ISO 1133 at 2.16 kg and 230 °C).

[0132] (b) 10 to 35% by weight of a polypropylene composition (PP), wherein, based on the total weight of the polypropylene composition (PP), the C2 content of the polypropylene composition (PP) is less than 3.4% by weight, the polypropylene composition (PP) is selected from polypropylene homopolymer (h-PP1), polypropylene random copolymer (r-PP), and a mixture of polypropylene random copolymer (r-PP) and polypropylene homopolymer (h-PP2), wherein the melt flow rate of the polypropylene homopolymer (h-PP1) (determined according to ISO 1133 at 2.16 kg and 230 °C) is 10 to 40 g / 10 min;

[0133] (c) 30 to 55% by weight of inorganic fillers;

[0134] The amount of each component is based on the total weight of the polyolefin composition. Preferably, the polyolefin composition has a crystallization temperature Tc (determined according to ISO 11357) of less than 125°C and a flexural modulus (determined according to ISO 178) of more than 2000 MPa.

[0135] All the preferred aspects, definitions, and implementation methods described above should also apply to the manufacturing method.

[0136] Preferably, the polyolefin composition is prepared by melt blending on a co-rotating twin-screw extruder (ZSK). The individual components (PCR-PO, PP, and inorganic filler) are added to the apparatus (e.g., the co-rotating twin-screw extruder) and mixed. Alternatively, at least one of the individual components (PCR-PO, PP, and inorganic filler) is premixed outside the apparatus (e.g., in a mixing silo), and then the remaining components are added to the apparatus for final mixing to obtain the polyolefin composition. Any suitable apparatus can be used. After mixing, the polymer melt mixture can be discharged and granulated.

[0137] The key points of the present invention will be further listed in the following embodiments.

[0138] Example Section

[0139] 1. Testing Method

[0140] a) Melt flow rate

[0141] As shown, the melt flow rate was measured at 230°C under a load of 2.16 kg (MFR2). The melt flow rate is the amount of polymer (in grams) extruded within 10 minutes at 230°C and a load of 2.16 kg using a test apparatus standardized to ISO 1133. MFR2 (230°C) was measured according to ISO 1133 (230°C, 2.16 kg load).

[0142] b) Tensile modulus [MPa]

[0143] The tensile modulus was measured according to ISO 527-2 (Cross Head speed = 50 mm / min; 23°C, unless otherwise specified) using injection-molded samples (dog bone shape, 4 mm thick) as described in EN ISO 1873-2. Yield stress was determined at a speed of 50 mm / min.

[0144] c) Charpy Notched Impact Strength (NIS)

[0145] Charpy notched impact strength was determined according to ISO 179-1 / 1eA on a sample with a notch of 80 mm × 10 mm × 4 mm (samples were prepared according to ISO 179-1 / 1eA). The test temperature was 23 ± 2 °C. Injection molding was performed according to ISO 19069-2.

[0146] d) Flexural modulus [MPa]

[0147] The flexural modulus was determined on an 80mm × 10mm × 4mm sample according to ISO 178 Method A (3-point bending test). A test speed of 2mm / min and a span length of 16 times the thickness were used, as per the standard. The test temperature was 23±2℃, and injection molding was performed according to ISO 19069-2.

[0148] e) DSC analysis, melting temperature (Tm) and heat of fusion (Hf), crystallization temperature (Tc) and enthalpy of fusion (Hm)

[0149] DSC was measured on samples ranging from 5 to 7 mg using a TA Instrument Q2000 differential scanning calorimetry (DSC). The DSC was operated in hot / cold / hot cycling at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C, according to ISO 11357 / Part 3 / Method C2. The crystallization temperature (Tc) was determined by a cooling step, and the melting temperature (Tm) and enthalpy of fusion (Hm) were determined by a second heating step. Crystallinity can be calculated from the enthalpy of fusion by assuming an Hm value of 209 J / g for fully crystalline polypropylene (see Brandrup, J., Immergut, EH, Eds., 3rd ed., Wiley, New York, 1989; Chapter 3).

[0150] f) Shrinkage rate

[0151] Shrinkage was measured on a 60×60×2mm quadratic plaque (injection molded). The film gate sample was injection molded on a 20 Engel V60 injection molding machine equipped with a small ( L / D = 20 screw. The method parameters were: melt temperature 200°C, flow front velocity 100 mm / s, holding time 10 seconds, and hydraulic holding pressure level 10 bar. At least 96 hours after demolding, the patch dimensions (length and width) were measured and compared with the cavity dimensions at room temperature (25°C).

[0152] g) Crystallization half-life

[0153] The crystallization half-life was determined using differential scanning calorimetry (DSC). This method replaces the "crystallization rate" test according to ISO 11357-7, and specifically considers only the isothermal crystallization rate. Samples were heated to 225°C at a rate of 10 or 20°C / min, which is significantly higher than the melting temperature of isotactic polypropylene. To remove thermal history, the samples were held at this temperature for at least 5 minutes. Subsequently, the samples were rapidly quenched to the isothermal crystallization temperature. In this study, the isothermal crystallization temperature was defined as 135°C. During isothermal crystallization, the heat flux over time was recorded. The crystallization half-life was determined as the peak value of the heat flux / time curve. The crystallization half-life represents the time it takes for half of the sample to solidify at the selected temperature.

[0154] h) The crystalline and soluble fractions and their respective properties (Crystex analysis)

[0155] The crystalline and soluble fractions (CF) of the polyolefin (PO) composition, the final ethylene unit content of the PO composition, the ethylene unit content of each fraction, and the intrinsic viscosity of each fraction were analyzed using a CRYSTEX QC Polymer Char (Valencia, Spain) according to ISO 6427 Annex B: 1992(E). A schematic diagram of the CRYSTEX QC instrument is described in DelHierro, P.; Ortin, A.; Monrabal, B.; 'Soluble Fraction Analysis in polypropylene, The Column, February 2014, pp. 18-23. The crystalline and amorphous fractions were separated by temperature cycling, which involved dissolving in 1,2,4-trichlorobenzene (1,2,4-TCB) at 160°C, crystallizing at 40°C, and redissolving in 1,2,4-TCB at 160°C. The quantification of SF and CF and the determination of ethylene content (C2) were achieved using an infrared detector (IR4), and the intrinsic viscosity (IV) was determined using an online 2-capillary viscometer.

[0156] The IR4 detector is a multi-wavelength detector capable of detecting two different wavelengths (CH3 tensile vibration (center at approximately 2960 cm)). -1 ) and CHx tensile vibration (2700-3000cm) -1 The IR absorbance of ethylene-propylene copolymers (EP copolymers) can be used to determine the concentration and ethylene content in these copolymers. The IR4 detector is calibrated using a series of eight EP copolymers with known ethylene contents ranging from 2 wt% to 69 wt% (determined by 13C-NMR) and concentrations ranging from 2 to 13 mg / ml for each copolymer. To simultaneously account for both the concentration and ethylene content of the various polymers expected during Crystex analysis, the following calibration equation is applied:

[0157] Equation 1:

[0158] Concentration = a + b * Abs(CH) + c * (Abs(CH)) x )) 2 +d*Abs(CH3)+e*(Abs(CH3)) 2 +f*Abs(CH x )*Abs(CH3)

[0159] Equation 2:

[0160] CH3 / 1000C=a+b*Abs(CHx )+c*Abs(CH3)+d*(Abs(CH3) / Abs(CH x ))+e*(Abs(CH3) / Abs(CH x )) 2

[0161] Least square regression analysis was used to determine the constants a to e in Equation 1, and the constants a to f in Equation 2.

[0162] Equation 3:

[0163] Use the following relationship to convert CH3 / 1000C to ethylene content in weight percent:

[0164] Weight % (ethylene in EP copolymer) = 100 - CH3 / 1000TC * 0.3

[0165] The amounts of the soluble fraction (SF) and crystalline fraction (CF) were correlated with the "cold-soluble xylene" (XCS) and "cold-insoluble xylene" (XCI) fractions, respectively, by XS calibration, determined according to the ISO 16152 standard gravimetric method. XS calibration was achieved by testing various EP copolymers with XCS content ranging from 2% to 31% by weight. The determined XS calibration was linear.

[0166] (Equation 4):

[0167] % by weight x CS = 1.01 * % by weight SF

[0168] The intrinsic viscosity (IV) of the parent EP copolymer, as well as its soluble fraction (SF) and crystalline fraction (CF), was determined using an online 2-capillary viscometer and correlated with the corresponding IV, which was determined according to the standard method for decahydronaphthalene according to ISO 1628-3.

[0169] Calibration was performed using various commercially available EP and PP copolymers with IV = 2-4 dL / g. The calibration curve between the determined Vsp (measured in CRYSTEX QC and normalized to concentration (c)) and IV was linear (Equation 5):

[0170] IV(dl / g)=a*Vsp / c

[0171] The slope a = 16.2.

[0172] Weigh the sample of the PO composition to be analyzed at a concentration of 10 mg / ml to 20 mg / ml. After filling the vial with 1,2,4-TCB containing 250 mg / L of 2,6-tert-butyl-4-methylphenol (BHT) as an antioxidant, dissolve the sample at 160°C until completely dissolved, typically for 60 minutes, with continuous stirring at 400 rpm to 800 rpm. To prevent sample degradation, cover the polymer solution with a nitrogen atmosphere during the dissolution process.

[0173] A predetermined volume of sample solution is injected into a column filled with an inert support, where sample crystallization and separation of the soluble and crystalline fractions occur. This process is repeated twice. During the first injection molding, the entire sample is measured at high temperature, and the IV [dl / g] and C2 [wt%] of the PO composition are determined. During the second injection molding, the soluble fraction (SF, at a low temperature of 40°C) and the crystalline fraction (CF, at a high temperature of 160°C) are determined by crystallization cycling (wt% SF, wt% C2, IV).

[0174] based on 13 C2 content was determined by C1NMR spectroscopy for calibration standards.

[0175] Quantization was recorded in solution using a Bruker Avance III 400 NMR spectrometer. 13 C{ 1 ¹H NMR spectra were recorded at 400.15 MHz and 100.62 MHz, respectively. 1 H and 13 C. All spectra are used. 13A C-optimized 10mm extended temperature probe was used for recording at 125°C, and nitrogen was used for all pneumatic devices. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) and chromium acetylacetone (Cr(acac)3) to obtain a 65 mM relaxant solution in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure solution homogeneity, the NMR tube was further heated in a rotary furnace for at least 1 hour after initial sample preparation in a heating block. The tube was rotated at a frequency of 10 Hz after inserting a magnet. This setup was chosen primarily for high resolution and the precise ethylene content quantification required for quantification. Standard single-pulse excitation was used without NOE, employing an optimized tip angle, a 1-second cyclic delay, and a dual-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225, Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6 k) transients were acquired for each spectrum. Quantization... 13 C{ 1 The ¹H NMR spectra were processed, integrated, and the relevant quantitative properties were determined from the integration. Chemical shifts of the solvent were used, with all chemical shifts indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm. This method allows for comparable references even if the structural unit is absent. Characteristic signals corresponding to ethylene incorporation were observed (Cheng, HN, Macromolecules 17 (1984), 1950), and the comonomer portion was calculated as the fraction of ethylene in the polymer relative to all monomers in the polymer.

[0176] fE = (E / (P+E))

[0177] The comonomer portion uses the method of Wang et al., through... 13 C{ 1In H} spectra, multiple signals across the entire spectral region are integrated for quantization (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157). This method was chosen for its stable performance and ability to account for regional defects when needed. Slight adjustments were made to the overall region to increase applicability across the entire range of comonomer contents involved. For systems with very low ethylene content, only isolated ethylene was observed in the PPEPP sequence. A modification of Wang et al.'s method was made to reduce the influence of integration at sites that no longer exist. This method reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine the absolute ethylene content.

[0178] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0179] By using this set of points, the corresponding integral equation becomes

[0180] E = 0.5(I H +I G +0.5(I C +I D ))

[0181] The same notation as used in the literature of Wang et al. was employed. No modifications were made to the equations for absolute propylene content. The molar percentage of comonomer incorporation was calculated using the following molar fractions:

[0182] E[mol%]=100*fE

[0183] Use this mole fraction to calculate the weight percentage of comonomer incorporated:

[0184] E[weight%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0185] i) Density

[0186] Density was measured according to ISO 1183-187. Samples were prepared by compression molding according to ISO 1872-2:2007.

[0187] j) Cold-soluble fraction of xylene (XCS wt%)

[0188] The cold-soluble fraction of xylene can be determined at 23°C according to ISO 6427.

[0189] k) Heat distortion temperature (HDT)

[0190] HDT was prepared according to ISO 1873-2 in an 80x10x4 mm diameter.3 The test was performed on injection-molded samples and stored at +23°C for at least 96 hours prior to measurement. The test was conducted on a planar support sample according to ISO 75 Condition A, with a nominal surface stress of 0.45 MPa.

[0191] Material

[0192] The PCR-PO materials used have the properties listed in Table 1.

[0193] Table 1: Properties of PCR-PO materials

[0194]

[0195]

[0196] Table 2 summarizes the properties of commercially available (Borealis) polypropylene homopolymers (h-PP) and random copolymers (r-PP) for application. The applied polypropylene homopolymers (h-PPa to h-PPc) have a C2 content of less than 0.1% by weight.

[0197] The h-PP-based carrier HC001A with a density of 905 kg / m³ was used. 3 The MFR2 (determined according to ISO 1133 at 2.16 kg and 230 °C) was 2.7 g / 10 min, and the crystallization temperature Tc was 112 °C.

[0198] The chalk was Calcitec M / 5 from Mineraria Sacilese, with 99% of the particles being <20 μm in size.

[0199] Table 2: Properties of Polypropylene Compositions; *Unless otherwise stated, the remaining % by weight are attributed to polypropylene homopolymers.

[0200]

[0201] experiment

[0202] The compositions were prepared by melt blending on a co-rotating twin-screw extruder (ZSK) according to the formulations given in Table 3. The polymer melt mixture was discharged and granulated. The mechanical properties of the compositions are also given in Table 3. It should be understood that h-PPa in IE1 is used as h-PP1, h-PPc in IE2 is used as h-PP1, and h-PPa in IE4 is used as h-PP2.

[0203] Table 3: Comparative and Inventive Examples of Polypropylene Compositions; nm – Not measured

[0204]

[0205] As can be seen, the polyolefin composition of the present invention not only provides a sufficient tensile modulus greater than 2000 MPa, but also a satisfactory MFR2 value greater than 12 g / 10 min. Furthermore, the polyolefin composition of the present invention provides sufficient crystallization temperature and crystallization half-life values. In addition, the low anisotropic shrinkage coefficient below 1.35 ensures good dimensional stability.

[0206] It should be considered that when producing thick injection molded parts (>3 mm) with an MFR range of >12 g / 10 min, polymer compositions with slow crystallization kinetics and low crystallinity may be preferred. Crystallization temperature and crystallization half-life can be used as measures of crystallization kinetics. A longer crystallization half-life or a lower crystallization temperature means slower crystallization kinetics, smaller crystals, and lower shrinkage. For semi-crystalline polymers, high crystallinity means high volume shrinkage of the material. As shown in the prior art, volume shrinkage and asymmetric cooling conditions lead to the accumulation of internal stress [T. Glomsaker, EL. Hinrichsen, Larsen, P. Doshev, E. Ommundsen, Warpage-Crystallinity relations in rotational molding of polypropylene, Polym. Eng. And Sci., 522-530, 2009, DOI 10.1002 / pen.21322]. Therefore, achieving a balance between limited anisotropy and stiffness and impact performance remains a major challenge. The anisotropy of the polymer compositions of this invention and comparative polymer compositions is expressed as the ratio of flow shrinkage to transverse shrinkage. In this way, the anisotropic shrinkage coefficient of the current polymer system is calculated. A higher shrinkage coefficient indicates higher anisotropy in the polymer composition, which may lead to internal residual stress, warping, and low dimensional stability.

[0207] Figure 1 The tensile modulus and anisotropic shrinkage coefficient of the inventive examples (white) and comparative examples (black) are shown as a function of the tensile modulus. It can be seen that, at similar anisotropic shrinkage coefficients, the tensile modulus of the inventive examples (IE3; MFR2 = 13 and IE4; MFR2 = 12) is higher than that of the comparative example CE2 (MFR2 = 10). Furthermore, compared to the comparative example CE1 (MFR2 = 7), IE1 (MFR2 = 13) exhibits an excellent combination of higher tensile modulus and lower anisotropic shrinkage coefficient. Inventive example IE2 (MFR2 = 19) demonstrates that a combination of high tensile modulus and low anisotropy can be maintained even in a high MFR range.

Claims

1. A polyolefin composition obtainable by mixing the following components: (a) 10 to 40 wt% of a post-consumer recycled polyolefin-based material (PCR-PO), wherein, said post-consumer recycled polyolefin-based material (PCR-PO) has a melt flow rate of 1 to 50 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C; (b) 10 to 35 wt.-% of a polypropylene composition (PP), wherein the C2 weight content of the polypropylene composition (PP) is less than 3.4 wt.-%, based on the total weight of the polypropylene composition (PP), and the polypropylene composition (PP) is selected from the group consisting of a polypropylene homopolymer (h-PP1) having a melt flow rate of 10 to 40 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C, a polypropylene random copolymer (r-PP), and a mixture of a polypropylene random copolymer (r-PP) and a polypropylene homopolymer (h-PP2); (c) 30 to 55 wt.-% of an inorganic filler, wherein the inorganic filler is calcium carbonate; wherein the amounts of each component are based on the total weight of the polyolefin composition, said polyolefin composition has a crystallization temperature Tc of 125 °C or less, determined according to ISO 11357, and a flexural modulus of 2000 MPa or more, determined according to ISO 178.

2. The polyolefin composition according to claim 1, wherein, said components are mixed in the following amounts: a) 20 to 38 wt.-% of a post-consumer recycled polyolefin-based material (PCR-PO); b) 15-33 wt.-% of a polypropylene composition (PP); and c) 35-50 wt.-% of an inorganic filler; wherein the amounts of each component are based on the total weight of the polyolefin composition.

3. The polyolefin composition according to claim 1, wherein, said post-consumer recycled polyolefin-based material (PCR-PO) is selected from the group consisting of a post-consumer recycled polypropylene-based material (PCR-PP), a post-consumer recycled polyethylene-based material (PCR-PE), and mixtures thereof.

4. The polyolefin composition according to claim 1, wherein, said post-consumer recycled polyolefin-based material (PCR-PO) has a melt flow rate of 2 to 40 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C, and / or said post-consumer recycled polyolefin-based material (PCR-PO) has at least one of the following: a limonene content of 0.05 to 500 ppm, determined by standard addition method using headspace solid phase microextraction (HS-SPME-GC-MS); a polystyrene content of at most 6.0 wt.-%; a talc content of at most 3 wt.-%; a chalk content of at most 1.0 wt.-%; a polyamide content of at most 5.0 wt.-%; a fatty acid content of 1.0 to 100 ppm, determined by standard addition method using headspace solid phase microextraction (HS-SPME-GC-MS).

5. The polyolefin composition according to claim 1, wherein, the C2 weight content of the polypropylene composition (PP) is less than 3.2 wt.-%, based on the total weight of the polypropylene composition (PP).

6. The polyolefin composition according to claim 1, wherein, the polypropylene composition (PP) is a polypropylene homopolymer (h-PP1) having a crystallization temperature Tc of 90 to 128 °C, determined according to ISO 11357.

7. The polyolefin composition according to claim 1, wherein, The polypropylene composition (PP) is a polypropylene homopolymer (h-PP1) having a melt flow rate of 12 to 35 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C, and / or The polypropylene homopolymer (h-PP1) has a flexural modulus of 900 to 2500 MPa, determined according to ISO 178.

8. The polyolefin composition according to claim 1, wherein, The polypropylene composition (PP) is a polypropylene random copolymer (r-PP) having a crystallization temperature Tc of more than 105 to 115 °C, determined according to ISO 11357; or The polypropylene composition (PP) is a mixture of a polypropylene random copolymer (r-PP) having a crystallization temperature Tc of more than 95 to 110 °C, determined according to ISO 11357, and a polypropylene homopolymer (h-PP2) having a crystallization temperature Tc of more than 115 to 140 °C, determined according to ISO 11357.

9. The polyolefin composition according to claim 1, wherein, The polyolefin composition has a crystallization temperature Tc of 124 °C or less, determined according to ISO 11357.

10. The polyolefin composition according to claim 1, wherein, The polyolefin composition has a flexural modulus of 2000 to 2500 MPa, determined according to ISO 178.

11. The polyolefin composition according to claim 1, wherein, The polyolefin composition has a melt flow rate of 9 to 35 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C.

12. An injection molded article comprising the polyolefin composition according to any one of claims 1 to 11.

13. The injection molded article according to claim 12 having a flow shrinkage of less than 1.58 %, measured on a 60 x 60 x 2 mm plaque, a cross flow shrinkage of less than 1.18 %, measured on a 60 x 60 x 2 mm plaque, and / or an anisotropic shrinkage factor, i.e. flow shrinkage SH-inF / cross flow shrinkage SH-crossF, of 1.38 or less, measured according to EN ISO 1873-2 on a 60 x 60 x 2 mm plaque.

14. A process for manufacturing a polyolefin composition, the process comprising the step of mixing the following components to obtain a polyolefin composition: (a) 10 to 40 weight percent of a post-consumer recycled polyolefin-based material (PCR-PO), wherein, The post-consumer recycled polyolefin-based material (PCR-PO) has a melt flow rate of 1 to 50 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C; (b) 10 to 35 wt.-% of a polypropylene composition (PP), wherein the C2 weight content of the polypropylene composition (PP) is less than 3.4 wt.-%, based on the total weight of the polypropylene composition (PP), the polypropylene composition (PP) is selected from a polypropylene homopolymer (h-PP1) having a melt flow rate of 10 to 40 g / 10 min, determined according to ISO 1133 at 2.16 kg, 230 °C, a polypropylene random copolymer (r-PP), and a mixture of a polypropylene random copolymer (r-PP) and a polypropylene homopolymer (h-PP2); and (c) 30 to 55 wt.-% of an inorganic filler, wherein the inorganic filler is calcium carbonate; wherein the amounts of each component are based on the total weight of the polyolefin composition.

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