Post-consumer recycled colored polypropylene composition

Abstract

The present invention relates to a process for producing a crystalline fraction (CF) having a content in the range of 85.0-95.0 wt. %, a soluble fraction (SF) having a content in the range of 5.0-15.0 wt. %, a total ethylene content (C2) having a content in the range of 2.0-10.0 wt. %, and a crystalline fraction (CF) having a content in the range of 85.0-95.0 wt. %, the total ethylene content being measured according to CRYSTEX QC analysis. 13 (v) the propylene content (C3(CF)) measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of 93.0-99.0 wt.%; and (v) the crystalline fraction (CF) is quantitative. 13 (vi) the ethylene content (C2(CF)) measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of [C2]-3.4 wt% to [C2]-0.2 wt%, where [C2] is the total ethylene content (C2) as defined in (iii) and (vi) the CIELAB color space (L * a * b * ) is L * is 30.0 to 73.0, and a * is -10 to 25, b * The present invention relates to a polypropylene mixed color blend, wherein the .DELTA..times ...

Description

[Technical field]

[0001] The present invention relates to mixed color polypropylene blends derived from post consumer recycled (PCR) materials. [Background technology]

[0002] 2. Background of the Invention The challenge of disposing of accumulated plastic waste and the associated environmental problems have attracted widespread attention from the public and industry. Therefore, recycling of plastic materials has become an important topic, which can turn plastic waste into a valuable resource for new plastic products. Thus, in the recycling and reuse of plastic materials, environmental and economic aspects can be combined.

[0003] Recycling of plastic materials started already in the mid-1990s with the introduction of collection systems. Although collection systems allow a more targeted collection and separation of plastic materials from other household waste, the reuse of plastic materials derived from plastic waste is still limited. So-called post-consumer recycled (PCR) plastic materials generally contain a mixture of different plastics and some contaminants. Methods for further purification of post-consumer recycled (PCR) plastic materials have been developed.

[0004] Many attempts have been made to purify recycle streams derived from post-consumer plastic waste, including washing, sieving, aeration, distillation, etc. For example, WO2018 / 046578A1 discloses a method for producing polyolefin recycle from mixed color polyolefin waste, including packaging waste, comprising cold washing the waste with water, then washing with an alkaline medium at 60°C, followed by flake color sorting to obtain a color-sorted monopolyolefin-rich fraction.

[0005] US 5,767,230A describes a method that involves contacting a PCR polyolefin chip containing volatile impurities with a heated gas at a superficial velocity sufficient to significantly reduce the volatile impurities, such as odor-active substances. However, so far contamination with residual benzene amounts has proven problematic. The origin of residual benzene in post-consumer recycled materials remains doubtful, but it represents an obstacle for end-use applications in areas such as medical packaging, food packaging, etc. Residual amounts of benzene, i.e. traces of benzene, are particularly problematic, since odor testing by olfactory experiments is not possible. End-use applications with specific requirements regarding odor are therefore excluded.

[0006] WO2020 / 182435A1 discloses a polymer composition consisting of 50-90 wt.% recycled polypropylene; 4-50 wt.% talc; 0-10 wt.% additives selected from the group of polyethylene (PE), maleic anhydride grafted PE (PE-MA), maleic anhydride grafted PP (PP-MA), stabilizers, peroxides, calcium oxide (CaO), or colorants, where the talc has a D50 (ISO13317-3) of less than 4 microns, and the weight percentages are relative to the total weight of the polymer composition.

[0007] As a further problem, known recyclates suffer from moderate homogeneity problems as reflected in the surface contamination that occurs in injection molded parts.

[0008] Post-consumer polypropylene-based recycled materials (PP-PCR) prepared from mechanical recycling processes remain challenging to meet certain requirements, such as purity, contaminants, light / white color, odor, quality consistency, batch-to-batch consistency, and homogeneity.

[0009] Therefore, there remains a high demand for recycled materials with properties as close as possible to those of virgin resins.Specifically, the object of the present invention is to provide a PP-PCR material that is superior to existing materials in that it has a higher product purity in terms of polypropylene content, a lower contaminant content, a lighter shade of gray, lower emissions (e.g., total carbon emissions, VOCs, FOGs), higher color consistency, higher homogeneity, higher tensile strength, and better processability. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2018 / 046578 [Patent Document 2] U.S. Patent No. 5,767,230 [Patent Document 3] International Publication No. 2020 / 182435 Summary of the Invention

[0011] Summary of the Invention The objective of the present invention is to provide a post-consumer recycled polypropylene composition that addresses the above-mentioned needs and shortcomings. Thus, the present invention provides (i) the crystalline fraction (CF) content, as determined herein, is in the range of 85.0-95.0 wt.% as determined according to CRYSTEX QC analysis; (ii) a soluble fraction (SF) content, as determined herein, in the range of 5.0-15.0 wt. % as measured according to CRYSTEX QC analysis; (iii) the total ethylene content (C2), as determined herein according to CRYSTEX QC analysis, is in the range of 2.0 to 10.0 wt.%; (iv) The crystalline fraction (CF), as defined herein, is quantitatively 13The propylene content (C3(CF)) measured by FT-IR spectroscopy calibrated with C-NMR spectroscopy is in the range of 93.0-99.0 wt%; (v) The crystalline fraction (CF), as defined herein, is quantitatively 13 the ethylene content (C2(CF)) measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of [C2]-3.4 wt% to [C2]-0.2 wt%, where [C2] is the total ethylene content (C2) as defined in (iii); (vi) CIELAB color space (L) measured according to DIN EN ISO 11664-4 as described herein * a * b * )teeth, -L * is 30.0~73.0, -a * -10 to 25, -b * -5~20 The present invention provides a polypropylene mixed color blend comprising:

[0012] Further, the present invention relates to a) providing a mixed plastic recycle stream (A); b) sieving the mixed plastics recycle stream (A) to prepare a sieved mixed plastics recycle stream (B) having only articles with a longest dimension in the range of 30-400 mm; c) classifying the sieved mixed plastic recycle stream (B) by one or more classification systems including near infrared (NIR) and optical sensors, whereby the sieved mixed plastic recycle stream (B) is classified at least by color and polymer type and optionally by article form, thereby preparing a classified mixed color polypropylene recycle stream (CM) for subsequent steps d); d) shredding the classified mixed color polypropylene recycle stream (CM) to prepare a flaked mixed color polypropylene recycle stream (D); e) washing the flaked mixed color polypropylene recycle stream (D) with a first aqueous wash solution (W1) without input of thermal energy to prepare a first suspended polypropylene recycle stream (E); f) removing at least a portion of the first aqueous wash liquid (W1) from the first suspended polypropylene recycle stream (E) to obtain a first washed polypropylene recycle stream (F); g) preparing a second suspended polypropylene recycle stream (G) by washing the first washed polypropylene recycle stream (F) with a second aqueous washing liquid (W2), introducing sufficient thermal energy into the second suspended polypropylene recycle stream (G) to provide a temperature during washing in the range of 65-95°C; h) removing the second aqueous wash liquid (W2) and material not suspended on the surface of the second aqueous wash liquid (W2) from the second suspended polypropylene recycle stream (G) to obtain a second washed polypropylene recycle stream (H); i) drying the second washed polypropylene recycle stream (H), thereby obtaining a dried polypropylene recycle stream (I) comprising a polypropylene mixed color blend according to the present invention. The present invention provides a method for recycling polypropylene mixed color material, comprising:

[0013] The present invention further provides articles comprising the polypropylene mixed color blends of the present invention, wherein said polypropylene mixed color blends preferably comprise at least 85% by weight, more preferably at least 90% by weight, and even more preferably at least 93% by weight of the ingredients for making the articles. These articles are particularly useful in making caps, closures, bottles, containers, automotive articles, and wire and cable articles.

[0014] The polypropylene mixed color blends according to the present invention may preferably further comprise at least one virgin polypropylene and / or additional recycled polypropylene to produce blends which are useful for manufacturing the above-mentioned articles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Detailed Description of the Invention For the purposes of this specification and the claims that follow, the term "recycled waste" is used to denote materials recovered from post-consumer waste, rather than virgin polymers and / or materials. Post-consumer waste refers to objects that have completed at least their first cycle of use (or life cycle), i.e., have already fulfilled their initial purpose. The term "virgin" refers to newly produced materials and / or objects that have not yet been recycled and have not yet been used for the first time. The term "recycled material" as used herein refers to materials that have been reprocessed from "recycled waste".

[0016] A blend is a mixture of two or more components, at least one of which is a polymer. In general, blends can be prepared by mixing two or more components. Suitable mixing procedures are known in the art. When such blends include virgin material, the virgin material is preferably polypropylene comprising at least 90% by weight of reactor-produced polypropylene material, and optionally carbon black. Virgin material is polymeric material that has not yet been recycled.

[0017] For purposes of this specification and the claims that follow, the term "polypropylene mixed color blend" refers to a polymeric material that contains primarily propylene-derived units, apart from other polymeric components of any nature. Such polymeric components may be derived, for example, from monomeric units derived from α-olefins such as ethylene, butylene, octene, styrene derivatives such as vinylstyrene, substituted and unsubstituted acrylates, substituted and unsubstituted methacrylates.

[0018] The polymeric material may be a polymeric material having a quantitative 13 It can be identified in polypropylene mixed color blends by C{1H} NMR measurement. The quantitative measurement used herein and described in the measurement method below. 13In the C{1H} NMR measurement, different units in the polymer chain can be distinguished and quantified. These units are propylene units (C3 units), units with 2, 4 and 6 carbons, and units with 7 carbon atoms. Thus, units with 2 carbon atoms (C2 units) can be distinguished in the NMR spectrum as consecutive C2 units and as isolated C2 units, which indicates that the polymer material contains an ethylene-based polymer. The polypropylene mixed color blend according to the present invention usually contains a small amount of ethylene-based polymer component.

[0019] Typically, fillers including organic and inorganic fillers such as talc, chalk, carbon black, additional pigments such as TiO2, and additional ingredients such as paper and cellulose may be present.

[0020] In the present invention, it has been found that the above objectives can be achieved by the polypropylene mixed color blends defined above.

[0021] The polypropylene mixed color blend in the present invention preferably has a crystalline fraction (CF) content, as measured according to CRYSTEX QC analysis, in the range of 85.0-93.0 wt%, more preferably 88.0-93.0 wt%.

[0022] The crystalline fraction (CF) of the polypropylene mixed color blend according to the present invention is preferably quantitatively 13 The propylene content (C3(CF)) measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is 94.0 to 99.0% by weight, more preferably 95.0 to 98.5% by weight.

[0023] The crystalline fraction (CF) of the polypropylene mixed color blend according to the present invention is preferably quantitatively determined as defined herein. 13The ethylene content (C2(CF)) as measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of [C2]-3.0 to [C2]-0.6 wt%, more preferably [C2]-2.4 to [C2]-1.2 wt%, where [C2] is the total ethylene content (C2) as measured according to CRYSTEX QC analysis.

[0024] The polypropylene mixed color blend preferably has a total ethylene content (C2), as measured according to CRYSTEX QC analysis, in the range of 2.5 to 8.0 wt.%, more preferably 3.0 to 6 wt.%, based on the total weight of the polypropylene mixed color blend.

[0025] The polypropylene mixed color blends according to the present invention preferably have a color reproducibility in the CIELAB color space (L) measured according to DIN EN ISO 11664-4 as described herein. * a * b * )but - 40~65L * - -8~20a * - -3~15b * where L * , a * and b * The above ranges can be combined independently of each other.

[0026] The polypropylene mixed color blend according to the present invention preferably has a soluble fraction (SF) as determined by CRYSTEX QC analysis of 6.0 to 11.0 wt %, more preferably 7.0 to 10.0 wt %.

[0027] The polypropylene mixed color blends according to the present invention are preferably 13The ethylene content in the soluble fraction (C2(SF)) obtained by CRYSTEX QC analysis, as measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy, is 21.0-28.0 wt%, more preferably 22.0-27.0 wt%.

[0028] The polypropylene mixed color blend according to the present invention preferably has an inorganic residue of 0.1 to less than 2.0 wt. %, more preferably 0.3 to 1.5 wt. %, based on the total weight of the polypropylene mixed color blend, as determined by thermal analysis (TGA) according to DIN ISO 1172: 1996. The result of thermal analysis (TGA) is also referred to herein as ash content.

[0029] The polypropylene mixed color blend according to the present invention preferably has a total carbon emission, measured by HS GC-FID according to VDA277, of 1.0 to 30 μg carbon / g, more preferably 5.0 to 25 μg carbon / g, based on the weight of the polypropylene mixed color blend.

[0030] The polypropylene mixed color blend according to the present invention preferably has a total volatile organic content (VOC) measured by HS GC-FID according to VDA278 of 10 to 150 μg / g, more preferably 20 to 120 μg / g, even more preferably 20 to 80 μg / g, based on the weight of the polypropylene mixed color blend.

[0031] The polypropylene mixed color blend according to the present invention preferably has a total condensable organic content (FOG) measured by HS GC-FID according to VDA278 of 20 to 450 μg / g, more preferably 30 to 420 μg / g, based on the weight of the polypropylene mixed color blend.

[0032] The polypropylene mixed color blends according to the present invention preferably have an odor (VDA270-B3) of 5.0 or less, more preferably 4.8 or less. It should be understood that many commercially available recycle grades that have no reported odor are actually worse because odor testing according to VDA270 is prohibited due to the presence of problematic substances.

[0033] The polypropylene mixed color blend according to the present invention preferably has a large amplitude oscillatory shear-nonlinear index (LAOS-NLF) measured at 190° C., an angular frequency of 0.628 rad / s, and a strain of 1000%. TIFF2025509945000001.tif932 is in the range of 1.5 to 3.5. In the formula, G1' is the first-order Fourier coefficient and G3' is the third-order Fourier coefficient.

[0034] Without intending to be bound by theory, it is believed that polymer processing contributes to the branching caused by encapsulated contaminants. LAOS-NLF can be influenced by selecting the feedstock such that approximately 10% by weight of the material is soft polypropylene. It should be understood that some regions operate collection stations that collect pre-sorted plastics at a high level by consumers. Such high-value plastic streams are commercially available and can upgrade lower quality streams (such as those with softer polypropylene mixtures) from other waste treatment resources.

[0035] The polypropylene mixed color blends according to the invention preferably have a tensile modulus (according to ISO 527-2 at a crosshead speed of 1 mm / min; 23° C.) of at least 1200 MPa, more preferably at least 1250 MPa, even more preferably at least 1300 MPa, using injection molded test specimens (dogbone shape, 4 mm thick) as described in EN ISO 1873-2. Such a relatively high flexural modulus is due to the relatively low amount of rubbery and plastomeric materials in the blend.

[0036] The polypropylene mixed color blend according to the present invention preferably has a tensile modulus in the range of 1200 to 1500 MPa, more preferably in the range of 1250 to 1480 MPa.

[0037] The polypropylene mixed color blends according to the present invention preferably have a tensile strength at break in the range of 5 to 350%, more preferably in the range of 10 to 200%, even more preferably in the range of 15 to 150%, measured according to ISO 527-2 as described in the examples below.

[0038] The polypropylene mixed color blend according to the present invention preferably has a Charpy impact strength of 3.5 to 12.0 kJ / m at 23° C. according to ISO 179-1 / 1eA, measured as described in the Examples below. 2 More preferably, it is in the range of 4.0 to 10.0 kJ / m 2 and more preferably in the range of 4.5 to 9 kJ / m 2 It is.

[0039] The polypropylene mixed color blend according to the present invention preferably has an intrinsic viscosity (IV(SF)) of the soluble fraction measured according to CRYSTEX QC analysis as measured in the examples described below in the range of 1.0 to 2.2 dL / g, more preferably 1.2 to 2.1 dL / g, and even more preferably 1.3 to 2.0 dL / g.

[0040] The polypropylene mixed color blend according to the present invention preferably has a shear thinning index (STF) value, defined as the ratio of the complex viscosity at 0.05 rad / s η(0.05) to the complex viscosity at 300 rad / s η(300) at 230°C, performed in the frequency range of 0.01 to 628 rad / s according to ISO 6721-1 and 6721-10, in the range of 7.5 to 15, more preferably in the range of 8.0 to 13. STF is a rheological measure that indicates the breadth of molecular weight of a polymer. The measurement of STF is described in the experimental section below. The higher the STF value, the broader the molecular weight of the material and the better the processability of the material.

[0041] The polypropylene mixed color blend according to the present invention preferably has a melt flow rate MFR at 230° C. measured according to ISO 1133 2.16 is at least 5 g / 10 min, more preferably at least 10 g / 10 min. 2.16 is preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less.

[0042] In certain applications, polypropylene mixed color blends may be obtained by visbreaking, preferably with peroxides. In these cases, the MFR 2.16 is preferably at least 50 g / 10 min, more preferably at least 100 g / 10 min, even more preferably at least 150 g / 10 min.

[0043] The visbreaking process may be preferably carried out either with a peroxide or a mixture of peroxides, or with a hydroxylamine ester or a mercaptan compound as a free radical source (visbreaking agent), or purely by pyrolysis. Decomposition products of the visbreaking process may be found in the resulting blend. It should be understood that decomposition products of the visbreaking process (commonly used in the art for virgin materials) are not considered impurities.

[0044] The process of visbreaking is known in the art and can be carried out, for example, as described in WO 2021 / 260053A1.

[0045] The density of the polypropylene mixed color blend according to the present invention is preferably 900 to 940 kg / m 3 , more preferably 905 to 935 kg / m 3 , and more preferably 910 to 930 kg / m 3 It is.

[0046] The polypropylene mixed color blends according to the invention are preferably obtained from post-consumer recycled (PCR), preferably from 100% PCR material. Such PCR material is typically obtained from consumer waste streams, such as waste streams generated in conventional collection systems (e.g. Extended Producer Responsibility, EPR, etc.) as implemented in the European Union. PCR material may also come from municipal solid waste generated outside the EPR collection system.

[0047] The raw materials for obtaining the polypropylene mixed color blends according to the invention can be selected from a wide range of fractions generated from municipal solid waste (MSS, often also called residual waste, black bin waste), up to Extended Producer Responsibility (EPR) based raw materials, for example the ARA414 fraction of Altstoff Recycling Austria, the DSD324 fraction of DSD-Duales System Holding, Interzero, Reclay or German producer responsibility organizations.

[0048] It is preferred that the polypropylene mixed color blends of the present invention are at least 95.0% by weight, more preferably at least 96% by weight, and even more preferably at least 97% by weight post-consumer derived.

[0049] The above object can also be achieved by the above polypropylene mixed color material recycling method, which includes the above steps a) to i). In other words, the polypropylene mixed color blend of the present invention is preferably obtained or has been obtained by the above method or the preferred method described below.

[0050] In step c), the sieved mixed plastics recycle stream (B) can preferably be further classified by article shape, for example by type of use (MFR) or specific target using an artificial intelligence classification system (e.g. available from Tomra Systems, etc.). In the classification step c), the white and natural colored waste materials are preferably classified such that substantially only non-white and / or non-natural colored waste materials remain in the one or more classified mixed color polypropylene recycle streams (CM).

[0051] The sorting step c) preferably results in one or more sorted mixed color polypropylene recycle streams (CM). This can be achieved by removing preferably white and natural color polypropylene articles and non-polypropylene articles. In this specification, "natural" means that the article is naturally colored. It means that the article is essentially free of colorants such as dyes or inks or pigments (including carbon black). On the other hand, "white" refers to the article containing white pigments. The same logic applies to the sorting of flakes as described in step k) below.

[0052] In step f), preferably substantially all of the first aqueous wash liquid (W1) is removed from the first suspended polypropylene polyolefin recycle stream (E) to obtain said first washed polypropylene polyolefin recycle stream (F).

[0053] In step h), the removal of the second aqueous washing solution (W2) and the material not floating on the surface of the second aqueous washing solution is preferably achieved by a density separation step.

[0054] The method of the present invention further comprises the steps of: j) separating the dried polypropylene recycle stream (I) obtained in step i) into a light fraction and a heavy fraction polypropylene recycle stream (J); k) further classifying the heavy fraction polypropylene recycle stream (J), or, if step j) is not present, the dried polypropylene recycle stream (I), using one or more optical classifiers to classify the one or more target polypropylenes by removing flakes containing materials other than the one or more target polypropylenes to prepare a purified polypropylene recycle stream (K); l) melt extruding and preferably pelletizing the purified polypropylene recycle stream (K) to prepare an extruded, preferably pelletized, recycled polypropylene product (L), preferably with the addition of additives (Ad) in the melt state; m) aerating the recycled polypropylene product (L) or, in the absence of step l), the purified polypropylene recycle stream (K) to remove volatile organic compounds to prepare an aerated recycled polypropylene product (M), which is either an aerated extruded and preferably pelletized recycled polypropylene product (M1), or an aerated recycled polypropylene flake (M2); may include at least one of Here, the order of steps l) and m) can be reversed so that the purified polypropylene recycle stream (K) is first aerated to prepare aerated recycled polypropylene flake (M2), which is then extruded, preferably with the addition of additives (Ad) in the melt state, to prepare an extruded, preferably pelletized, aerated recycled polypropylene product (M3), which is a polypropylene mixed color blend according to the present invention.

[0055] In step j), separation may preferably be performed by air sieving, or may be performed based on the aerodynamic properties of the particles (e.g. flakes, e.g. separating thin, light and flexible flakes from heavy, thick and hard flakes).

[0056] After the above step j), a sieving step j1) may be carried out in which the dried polypropylene recycle stream (I) is sieved to remove fines to prepare a sieved polypropylene recycle stream (J1), which is then subjected to the above optional step k). In this sieving step j1), fines, preferably having a size of 2.5 mm or less, are removed.

[0057] Furthermore, the present invention relates to an article made from the polypropylene mixed color blend according to the present invention, said polypropylene mixed color blend preferably representing at least 85% by weight, more preferably at least 90% by weight, even more preferably at least 93% by weight of the ingredients for making the article, said remaining ingredients may include additives such as antioxidants, stabilizers, colorants such as carbon black, pigments, dyes or inks, optionally in the form of a masterbatch.

[0058] According to the present invention, the article may be selected from the group consisting of caps, closures, bottles, containers, automotive articles, and wire and cable articles.

[0059] The present invention further relates to a blend comprising the polypropylene mixed color blend according to the present invention and at least one virgin polypropylene and / or additional recycled polypropylene. The virgin polypropylene may be selected from heterophasic polypropylene, random propylene copolymer, and propylene homopolymer. The additional recycled polypropylene may be the same or different from the polypropylene mixed color blend according to the present invention and may be derived from a commercial source as described above.

[0060] The present invention further relates to the use of the polypropylene mixed color blends according to the present invention in household applications, automotive applications, appliance applications, packaging, or wire and cable applications.

[0061] Measurement method The following definitions of terms and methods of measurement apply to the above general description of the invention and the following examples, unless otherwise indicated.

[0062] a) Melt flow rate The melt flow rate (MFR) is measured according to ISO 1133 and is given in g / 10 min. MFR is an index of the flowability and therefore processability of a polymer. The higher the melt flow rate, the lower the viscosity of the polymer. Here, MFR2 was measured at a temperature of 230°C and under a load of 2.16 kg.

[0063] b) Isotacticity and comonomer content of polypropylene Quantification of Microstructure by NMR Spectroscopy (Calibration Only) Quantitative nuclear magnetic resonance (NMR) spectroscopy was used for calibration.

[0064] quantitative 13 C{1H}NMR spectrum 1 H and 13 The NMR spectra were recorded in solution on a Bruker Avance Neo 400 NMR spectrometer operating at 400.15 MHz and 100.62 MHz for C, respectively. The spectra were recorded at 125 °C with nitrogen gas at total pressure. 13 All spectra were recorded using a C optimized 10 mm extended temperature probe head. Approximately 200 mg of material was dissolved in approximately 3 mL of 1,2-tetrachloroethane-d2 (TCE-d2) along with approximately 3 mg of BHT (2,6-di-tert-butyl-4-methylphenol, CAS 128-37-0) and chromium-(III)-acetylacetonate (Cr(acac)3) to prepare a 60 mM solution of the relaxation agent in the solvent as described in G. Singh, A. Kothari, V. Gupta, Polymer Testing 2009, 28(5), 475.

[0065] After preparing the first sample in a heat block to ensure a homogenous solution, the NMR tube was heated in a rotating oven for an additional hour or more. When inserted into the magnet, the tube was spun at 10 Hz. This setting was chosen primarily for the high resolution and quantitatively necessary for accurate ethylene content quantification. Standard single-pulse excitation was employed, without NOE, with an optimized tip angle, a 1 s recycle delay, and a two-level WALTZ16 decoupling scheme, as described in Z. Zhou, R. Kuemmerle, X. Qiu, D. Redwine, R. Cong, A. Taha, D. Baugh, B. Winniford, J. Mag. Reson. 187 (2007) 225 and V. Busico, P. Carbonniere, R. Cipullo, C. Pellecchia, J. Severn, G. Talarico, Macromol. Rapid Commun. 2007, 28, 1128. A total of 6144 (6k) transients were acquired per spectrum.

[0066] quantitative 13 C{1H} NMR spectra were processed, 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. This approach allowed for comparable referencing even in the absence of this structural unit.

[0067] The characteristic signals corresponding to ethylene incorporation were observed (as described in Cheng, HN, Macromolecules 1984, 17, 1950) and the comonomer fraction was calculated as the fraction of ethylene in the polymer relative to the total monomers in the polymer: fE = (E / (P+E)

[0068] The comonomer fraction was determined by the method of WJ. Wang and S. Zhu (Macromolecules 2000, 33 1157) 13Quantification was achieved by integrating multiple signals over the entire spectral region of the C{1H} spectrum, with the integration region slightly adjusted to increase applicability over the full range of comonomer contents encountered.

[0069] The mole percent incorporation of the comonomer was calculated from the mole fraction: E [mol%] = 100 * fE The weight percent incorporation of the comonomer was calculated from the mole fraction: E [% by weight] = 100 * ( fE * 28.06 ) / ( (fE * 28.06) + ((1-fE) * 42.08) ).

[0070] c) Crystex analysis, crystalline fraction (CF) and soluble fraction (SF) The crystalline fraction (CF) and soluble fraction (SF) of the PCR polypropylene compositions, as well as the ethylene content and intrinsic viscosity of each fraction, were analyzed using a CRYSTEX instrument from Polymer Char (Valencia, Spain) according to ISO 6427 Annex B. Details of the technique and method can be found in the literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer, Markus Gahleitner (2020) Rapid Characterization of Impact Ethylene-Propylene Copolymer Compositions by Crystallization Extraction Separation: Comparison with Standard Separation Methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596).

[0071] Crystalline and amorphous fractions are separated by temperature cycling: dissolution at 160° C., crystallization at 40° C., and redissolution in 1,2,4-trichlorobenzene at 160° C. Quantification of SF and CF and measurement of ethylene content (C2) are performed by an integrated infrared detector (IR4), and intrinsic viscosity (IV) is measured using an online two-capillary viscometer.

[0072] The IR4 detector detects two distinct bands (CH stretching vibration (center wavelength approximately 2960 cm)) that are useful for measuring the concentration and ethylene content of ethylene propylene copolymers. -1 ) and CH stretching vibration (2700-3000cm -1 )) is a multi-wavelength detector that measures IR absorbance in ethylene-containing polymers with known ethylene content between 2% and 69% by weight ( 13 The system is calibrated with eight different EP copolymers, each at various concentrations ranging from 2 to 13 mg / mL, in the range of 1000 to 10000 s (measured by C-NMR). For the various polymer concentrations expected during the Crystex analysis, the following calibration equation was applied to simultaneously detect both the concentration and ethylene content characteristics: TIFF2025509945000002.tif12158

[0073] Constants a to e in Equation 1 and constants a to f in Equation 2 were determined using least squares regression analysis.

[0074] CH3 / 1000C is expressed by the following equation: Weight % (ethylene in EP copolymer) = 100-CH3 / 1000TC * 0.3 The ethylene content is converted to weight percent using the formula:

[0075] The intrinsic viscosity (IV) of PCR polypropylene compositions and their soluble and crystalline fractions are measured using an online 2-capillary viscometer and correlated with the corresponding IV's measured by standard method in decalin according to ISO 1628-3. Calibration is performed with various EP PP copolymers with IV=2-4 dL / g. The determined calibration curve is a straight line: IV(dL / g)=a * Vsp / c It is.

[0076] The samples to be analyzed were weighed out at concentrations between 10 mg / mL and 20 mg / mL. To avoid the possibility of injecting gels and / or polymers that are not soluble in TCB at 160 °C, such as PET and PA, the weighed samples were packed into a stainless steel mesh with MW 0.077 / D 0.05 mm.

[0077] After automatically filling the vials with 1,2,4-TCB containing 250 mg / L of 2,6-tert-butyl-4-methylphenol (BHT) as an antioxidant, the samples are dissolved at 160 °C with constant stirring at 400 rpm, typically for 60 min, until completely dissolved. The polymer solution is covered with a nitrogen atmosphere during dissolution to prevent sample decomposition.

[0078] A defined amount of sample solution is injected into a column filled with an inert carrier, which allows the sample to crystallize and separate the soluble fraction from the crystalline portion. This process is repeated twice. In the first injection, the entire sample is measured at high temperature to determine the IV [dL / g] and C2 [wt%] of the PP composition. In the second injection, the soluble fraction (low temperature) and the crystalline fraction (high temperature) are measured in the crystallization cycle (wt% SF, wt% CF, wt% C2, IV). Wt% CF is calculated as follows: Weight%CF =100-Weight%SF It is calculated by the following method.

[0079] d) Cross-fractionation chromatography The determination of the chemical composition distribution as well as the molecular weight distribution and the corresponding molecular weight averages (Mn, Mw, Mv) at specific elution temperatures (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).

[0080] A CFC instrument (PolymerChar, Valencia, Spain) was used to perform cross-fractionation chromatography (TREF x SEC). A 4-band IR5 infrared detector (PolymerChar, Valencia, Spain) was used to monitor the concentration. The polymer was dissolved at 160°C for 150 min at a concentration of approximately 1 mg / mL.

[0081] To avoid injection of possible gels or polymers that are not soluble in TCB at 160° C., such as PET and PA, the weighed samples were packed into a stainless steel mesh of MW 0.077 / D 0.05 mm.

[0082] Once the sample was completely dissolved, 0.5 mL aliquots were loaded onto a TREF column and stabilized at 110° C. for a period of time. A constant cooling rate of 0.1° C. / min was applied to reach a temperature of 30° C. to crystallize and precipitate the polymer. A discontinuous elution process is carried out using the following temperature steps: (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).

[0083] In the second dimension, a 3PL Olexis column and 1x Olexis Guard column from Agilent (Church Stretton, UK) were used as stationary phase in the GPC analysis. As eluent, 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L of 2,6-di-tert-butyl-4-methylphenol) was applied at a constant flow rate of 1 mL / min at 150 °C. The column set was calibrated using a universal calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards ranging from 0.5 kg / mol to 11500 kg / mol. The following Mark Houwink constants were used to convert PS molecular weights to PP molecular weight equivalents: KPS=19×10-3mL / g, αPS=0.655 KPP=19×10-3mL / g, αPP=0.725

[0084] Calibration data was fitted using third order polynomial fitting. Data processing was performed using software provided by PolymerChar in conjunction with the CFC instrument.

[0085] e) Tensile modulus and tensile strain at break The tensile modulus and tensile strain at break were determined according to ISO 527-2 (crosshead speed = 1 mm / min, test speed 50 mm / min, 23 °C) using injection-molded test specimens (dogbone shape, thickness 4 mm) as described in EN ISO 1873-2. The measurements are carried out after conditioning the test specimens for 96 hours.

[0086] f) Impact strength (Charpy NIS) Impact strength was measured as notched Charpy impact strength (1 eA) according to ISO 179-1 eA at +23°C (non-instrumented, ISO 179-1, +23°C) on injection-molded specimens of 80 x 10 x 4 mm prepared according to EN ISO 1873-2.

[0087] g) Inorganic residues Inorganic residues were determined by TGA using a Perkin Elmer TGA 8000 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 min and then increased to 950 °C at a heating rate of 20 °C / min under nitrogen. Ash content was evaluated as wt% at 850 °C.

[0088] h) CIELAB color space (L * a * b * ) CIE L * a * b * In a uniform color space, the color coordinates are: * -Brightness coordinate; a * -Red / Green coordinates (+a * for red, -a for * indicates green);b * -yellow / blue coordinates (+b * for yellow, -b for* indicates blue). * , a * , b * The coordinate axes define the three-dimensional CIE color space. Standard Konica Minolta colorimeter CM-3700A.

[0089] i) Odor (VDA270-B3) VDA270 is the quantification of odor properties of automotive trim materials. In this study, odor is judged according to variant B3 of VDA270 (2018). The odor of each sample is evaluated according to the VDA270 scale by each assessor, with the jar lids opened as little as possible. The 6-point scale consists of the following grades: grade 1: not perceptible, grade 2: perceptible but not unpleasant, grade 3: clearly perceptible but not unpleasant, grade 4: unpleasant, grade 5: very unpleasant, grade 6: unacceptable. The assessors must remain calm during the evaluation and are not allowed to prejudice each other by discussing individual results during the test. They are also not allowed to adjust their evaluation after testing another sample. For statistical reasons (and as allowed by VDA270), the assessors must use the full scale for their evaluation. The odor grade is therefore measured based on the average of all individual evaluations, rounded to an integer.

[0090] j) Total organic emissions from non-metallic materials (VDA 277, January 1995) The following method description provides the experienced reader with an overview of the relevant parameters. In case of doubt, only the original method is valid for comparison of results. Equivalent standards to VDA277 are PV3341 (Volkswagen) and VCS1027, 2749 (Volvo).

[0091] VDA 277 is intended for the determination of organic compounds emitted from non-metallic materials relevant for vehicle interiors. It allows the determination of emission potential using a combination of static headspace techniques and gas chromatography.

[0092] For transport and storage, samples must be packed sealed in aluminum-coated polyethylene bags. Unless otherwise stated, samples are not stored in the open or preconditioned in any other way before analysis. Before weighing the samples, the injection moulded parts are cut into small pieces without risking the samples being heated. Pellets are weighed directly without an additional cutting step.

[0093] 2 g of each sample are then placed in a 20 mL headspace vial and tightly closed. The vials are heated immediately prior to subsequent GC analysis. They are incubated at 120°C (+ / - 1°C) for 5 hours (+ / - 5 minutes) in a headspace sampler connected to a gas chromatograph by means of a heated transfer line. Chromatographic separation is performed on a so-called wax-type column (WCOT capillary column, 100% polyethylene glycol) and detection is performed with a flame ionization detector (FID).

[0094] The evaluation includes: - Height is more than three times the baseline noise, -The area is greater than 10% of the peak in the acetone region (the calibration solution concentration is 0.5 g / L) Only such peaks are considered.

[0095] The results are based on a semi-quantitative evaluation of the total peak area of ​​the sample chromatogram minus the blank peak area. The evaluation is referenced to a calibration with acetone and its carbon content, respectively. The resulting total emission values ​​(or TVOC = total volatile organic compounds) are thus expressed in carbon equivalents.

[0096] k) Thermal desorption analysis of organic emissions for the characterization of non-metallic materials (VDA278, October 2011) The following method description provides the experienced reader with an overview of the relevant parameters; in case of doubt, only the original method is valid for comparing results.

[0097] VDA278 is intended for the measurement of emissions from non-metallic materials such as fabrics, carpets, adhesives, sealants, foams, leather, plastic parts, films and sheets, paints, or combinations of materials used in molded parts of motor vehicles.

[0098] In a VDA278 experiment, volatile and semi-volatile substances are extracted from a sample in a thermal desorption process using heat and a flow of inert gas (usually helium). The extracted compounds are cryofocused in a cold trap and then hot-injected into a gas chromatograph for separation. Detection is by mass spectrometry.

[0099] The analysis involves the semi-quantification of two specifically defined cumulative emission values, namely the volatile organic compounds (VOCs) and the fraction of condensable substances (FOG values), as well as the measurement of individual substances.

[0100] In the VOC analysis, the sample is heated to 90 °C for 30 min to extract the volatile organic compounds taking into account the emission up to n-pentacosane (C25) in the chromatogram. In the FOG analysis, an additional thermal desorption step is performed. For this purpose, the sample is kept in the desorption tube after the VOC analysis and reheated to 120 °C for 60 min. The FOG value is defined as the fraction of semi-volatile organic compounds eluting between n-tetradecane (C14) and n-dotriacontane (C32) in the chromatogram. The semi-quantitative analysis of the VOC value is calculated as toluene equivalents. The FOG value is calculated as hexadecane equivalents, respectively.

[0101] The equipment used for the analysis must comply with the minimum requirements set out in VDA 278 (chapter 3.1).

[0102] Typical result variations of up to 15% can be expected within a single laboratory, but generally valid precision statements cannot be made, therefore separate series of measurements are required to investigate relevant matrices.

[0103] According to VDA 278 the results obtained are not suitable for the following purposes: - Further estimation of the health effects of emissions - Any use as a basis for estimating concentrations that may be present inside a completed vehicle under stationary, operating or operating-like conditions.

[0104] l) Dynamic rheology measurements Characterization of polymer melts by dynamic shear measurements follows ISO standards 6721-1 and 6721-10. Measurements were performed on an Anton Paar MCR501 stress-controlled rotational rheometer with a 25 mm parallel plate geometry. Measurements were performed on compression molded plates using a nitrogen atmosphere and strains set within the linear viscoelastic region. Oscillatory shear tests were performed at 190 °C and 200 °C for PE and PP, respectively, applying a frequency range of 0.01-600 rad / s and setting the gap at 1.3 mm. In dynamic shear experiments, the probe is subjected to uniform deformation with sinusoidally varying shear strain or shear stress (strain-controlled and stress-controlled modes, respectively). In controlled strain experiments, the probe is subjected to the following: (t) = γ0 sin(ωt) (1) The sinusoidal distortion may be expressed as: If the applied strain is within the linear viscoelastic region, the resulting sinusoidal stress response is: (t) = σ0 sin(ωt + δ) (2) It can be expressed as: In the above formula, σ0 and γ0 are the stress and strain amplitudes, respectively; ω is the angular frequency, δ is the phase shift (loss angle between the applied strain and the stress response) where t is time.

[0105] The results of dynamic testing 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 out-of-phase component of the complex shear viscosity η", and the loss tangent tan δ, which can be expressed as follows: It is expressed by:

number

[0106] The so-called shear thinning index (STF) is measured as shown in the following formula (9).

number

[0107] The values ​​are measured by a single-point interpolation procedure defined in the Rheoplus software. In situations where the given G* value is not achieved experimentally, the value is measured by extrapolation using the same procedure as before. In both cases (interpolation or extrapolation), the Rheoplus options "Interpolate y values ​​from parameters to x values" and "Logarithmic interpolation type" were applied.

[0108] These tests were performed on compression molded disks using cryomilled powder.

[0109] m) LAOS nonlinear viscoelasticity ratio The nonlinear viscoelastic behavior under shear flow was investigated by large amplitude oscillatory shear. This method requires the application of a sinusoidal strain amplitude γ0 at a given angular frequency ω for a given time t. If the applied sinusoidal strain is large enough, a nonlinear response will occur. In this case, the stress σ is a 20 function of the applied strain amplitude, time and angular frequency. Under these conditions, the nonlinear stress response is still a periodic function, but can no longer be expressed by a single harmonic sinusoid. The stress resulting from the nonlinear viscoelastic response [0-0] can be expressed by a Fourier series including the contributions of higher harmonics.

number

[0110] The nonlinear viscoelastic response was analyzed by applying large amplitude oscillatory shear (LAOS) [4-6]. Time sweep measurements were performed using an Alpha Technologies RPA 2000 rheometer coupled with a standard biconical die. During the measurements, the test chamber is sealed and a pressure of approximately 6 MPa is applied. LAOS tests are performed at a temperature of 190 °C, an angular frequency of 0.628 rad / s, and a strain of 1000%. To ensure that a steady state is reached, the nonlinear response is measured after at least 20 cycles are completed per measurement. The large amplitude oscillatory shear nonlinearity index (LAOS-NLF) is given by:

number

[0111] These tests were carried out on cryomilled powders. [1] JM Dealy, KF Wissbrun, Melt Rheology and Its Role in Plastics Processing: Theory and Applications; edited by Van Nostrand Reinhold, New York (1990) [2] S. Filipe, Non-Linear Rheology of Polymer Melts, AIP Conference Proceedings 1152, pp. 168-174 (2009) [3] M. Wilhelm, Macromol. Mat. Eng. 287, 83-105 (2002) [4] S. Filipe, K. HofstadLer, K. Klimke, AT Tran, Non-Linear Rheological Parameters for Characterization of Molecular Structural Properties in Polyolefins, Proceedings of Annual European Rheology Conference, 135 (2010) [5] S. Filipe, K. Klimke, AT Tran, J. Reussner, Proceedings of Novel Non-Linear Rheological Parameters for Molecular Structural Characterization of Polyolefins, Novel Trends in Rheology IV, Zlin, Check Republik (2011) [6] K. Klimke, S. Filipe, AT Tran, Non-Linear rheological parameters for characterization of molecular structural properties in polyolefins, Proceedings of European Polymer Conference, Granada, Spain (2011) EXAMPLES

[0112] Working Example The IE1 material was obtained from DSD324 (German Green Dot System) based on EPR-based material.

[0113] The IE2 feedstock was obtained from polypropylene sorted from municipal solid waste in Poland and Greece.

[0114] The raw material for CE1 was obtained from Purpolen® PP-70, a grey post-consumer recyclable material consisting mainly of pre-sorted municipal waste, which is a commercially available product manufactured by mtm plastics GmbH, Niedergebühle, Germany.

[0115] The raw material for CE2 was obtained from Van Werven BB2 06 / 2020, a rigid plastic waste material derived from flake-form post-consumer recyclates that had already been sorted and cleaned. The flakes are subjected to a pelletizing process to prepare pellets.

[0116] To obtain materials IE1 and IE2, the following process is carried out from these raw materials: Sorting non-polypropylene materials such as polystyrene, polyamide, polyethylene, metal, paper, wood, etc. to obtain post-consumer plastic materials; sorting natural (i.e. uncolored) and white products to obtain a post-consumer mixed color polypropylene recycle stream with a defined color mix, thereby resulting in a gray / grayish final color after extrusion (e.g. shampoo or shower gel bottles, cans, etc.); crushing the selected post-consumer plastic material having said prescribed color mix, washing it with aqueous solutions containing various detergents, followed by drying, air sieving and screening; further classifying the pretreated post-consumer plastic material to remove non-polyolefin and colored fractions to obtain a purified polypropylene polyolefin recycle stream; melt extruding the material to obtain a polypropylene blend in pellet form as an extruded pelletized recycled polypropylene product; and aerating the extruded pelletized recycled polypropylene product at a temperature in the range of 100-130°C by preheating the extruded pelletized recycled polypropylene product to a target temperature using an air stream having a temperature of at least 100°C. A polypropylene mixed color blend was obtained by

[0117] The properties of the resulting polypropylene mixed color blends and commercial samples are shown in the table below. [Table 1] TIFF2025509945000008.tif107135

[0118] From the above results, it can be seen that the recycled polypropylene mixed color blends according to IE1 and IE2 have higher purity expressed as C2 content, especially C2 content of the crystalline fraction (C2(CF)), and lower emission properties (total carbon emissions, VOC, FOG) than commercial products such as Purpolen® (CE1) and Van Werven (CE2). Furthermore, the compositions of the present invention had better mechanical properties such as tensile modulus, tensile strain at break, and impact strength.

[0119] The compositions of the present invention also exhibit high color consistency and lighter shades (CIELab).Furthermore, the compositions of the present invention exhibit good processability, as expressed by a higher shear thinning index, despite their lower MFR compared to the comparative examples.

Claims

1. (i) the crystalline fraction (CF) content, as determined herein, is in the range of 85.0-95.0 wt. % as measured according to CRYSTEX QC analysis; (ii) the soluble fraction (SF) content, as determined herein, is in the range of 5.0-15.0 wt. % as measured according to CRYSTEX QC analysis; (iii) the total ethylene content (C2), as determined herein, is in the range of 2.0 to 10.0 wt.%, as measured according to CRYSTEX QC analysis; (iv) The crystalline fraction (CF), as defined herein, is quantitatively １３ a propylene content (C3(CF)) in the range of 93.0 to 99.0 wt.% as measured by FT-IR spectroscopy calibrated with C-NMR spectroscopy; (v) The crystalline fraction (CF), as defined herein, is quantitatively １３ the ethylene content (C2(CF)) as measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of [C2]-3.4 wt.% to [C2]-0.2 wt.%, where [C2] is the total ethylene content (C2) as defined in (iii); (vi) CIELAB color space (L) measured according to DIN EN ISO 11664-4 as described herein. ＊ a ＊ b ＊ )teeth, -L ＊ is 30.0 to 73.0, -a ＊ -10 to 25, -b ＊ -5 to 20 A polypropylene mixed color blend.

2. 10. The polypropylene mixed color blend of claim 1, having an inorganic residue of 0.1 to less than 2.0 wt. % based on the total weight of the polypropylene mixed color blend, as determined by calcination analysis (TGA) according to DIN ISO 1172:1996.

3. 3. The polypropylene mixed color blend of claim 1 or 2, having a total carbon footprint of 1.0-30 μg carbon / g based on the total weight of the polypropylene mixed color blend as measured by HS GC-FID according to VDA277.

4. The soluble fraction (SF) obtained by CRYSTEX QC analysis was quantitatively １３ 4. The polypropylene mixed color blend of any one of claims 1 to 3, having an ethylene content (C2(SF)) in the range of 20.0 to 30.0 wt.% as measured by FT-IR spectroscopy calibrated by C-NMR spectroscopy.

5. Large Amplitude Oscillatory Shear-Nonlinear Index (LAOS-NLF) measured at 190° C., angular frequency of 0.628 rad / s, and strain of 1000%, as described herein [In the formula, G １ ' is the first-order Fourier coefficient, and G ３ ' are the third order Fourier coefficients. The polypropylene mixed color blend of any one of claims 1 to 4, wherein M is in the range of 1.5 to 3.

5.

6. 6. The polypropylene mixed color blend according to any one of claims 1 to 5, wherein the Shear Thinning Index (STF) value, defined as the ratio of complex viscosities η(0.05) to η(300) at 230°C in the frequency range of 0.01 to 600 rad / s according to ISO 6721-1 and 6721-10, measured as described herein, is in the range of 7.5 to 15, and / or the Total Condensable Organic Content (FOG), measured by HS GC-FID according to VDA 278, is in the range of 20 to 450 μg / g based on the total weight of the polypropylene mixed color blend.

7. A polypropylene mixed colour blend according to any one of claims 1 to 6, obtained by visbreaking with peroxides.

8. Melt flow rate MFR at 230° C., measured as described herein ２．１６ The polypropylene mixed colour blend of any one of claims 1 to 7, wherein the viscosity is at least 5 g / 10 min.

9. a) providing a mixed plastic recycle stream (A); b) sieving the mixed plastics recycle stream (A) to produce a sieved mixed plastics recycle stream (B) having only articles with a longest dimension in the range of 30-400 mm; c) classifying the sieved mixed plastic recycle stream (B) by one or more classification systems including near infrared (NIR) and optical sensors, whereby the sieved mixed plastic recycle stream (B) is classified at least by color and polymer type and optionally by article form, thereby preparing a classified mixed color polypropylene recycle stream (CM) for subsequent steps d); d) shredding the classified mixed color polypropylene recycle stream (CM) to prepare a flaked mixed color polypropylene recycle stream (D); e) washing the flaked mixed color polypropylene recycle stream (D) with a first aqueous wash solution (W1) without input of thermal energy to prepare a first suspended polypropylene recycle stream (E); f) removing at least a portion of the first aqueous wash liquid (W1) from the first suspended polypropylene recycle stream (E) to obtain a first washed polypropylene recycle stream (F); g) preparing a second suspended polypropylene recycle stream (G) by washing the first washed polypropylene recycle stream (F) with a second aqueous wash liquid (W2), introducing sufficient thermal energy into the second suspended polypropylene recycle stream (G) to provide a temperature during washing in the range of 65-95°C; h) removing the second aqueous wash liquid (W2) and material not suspended on the surface of the second aqueous wash liquid (W2) from the second suspended polypropylene recycle stream (G) to obtain a second washed polypropylene recycle stream (H); i) drying the second washed polypropylene recycle stream (H), thereby obtaining a dried polypropylene recycle stream (I) comprising the polypropylene mixed color blend according to any one of claims 1 to 8.

16. A method for recycling polypropylene mixed color materials, comprising:

10. The following steps: j) separating the dried polypropylene recycle stream (I) obtained in step i) into a light fraction and a heavy fraction polypropylene recycle stream (J); k) further classifying the heavy fraction polypropylene recycle stream (J), or, in the absence of step j), the dried polypropylene recycle stream (I), using one or more optical classifiers to classify the one or more target polypropylenes by removing flakes containing materials other than the one or more target polypropylenes to prepare a purified polypropylene recycle stream (K); l) melt extruding and preferably pelletizing the purified polypropylene recycle stream (K) to prepare an extruded, preferably pelletized, recycled polypropylene product (L), preferably with the addition of additives (Ad) in the melt state; m) aerating the recycled polypropylene product (L) or, in the absence of step l), the purified polypropylene recycle stream (K) to remove volatile organic compounds to prepare an aerated recycled polypropylene product (M), which is either an aerated extruded and preferably pelletized recycled polypropylene product (M1), or an aerated recycled polypropylene flake (M2); 10. The method of claim 9 further comprising at least one of: The order of steps l) and m) can be reversed such that a purified polypropylene recycle stream (K) is first aerated to prepare an aerated recycled polypropylene flake (M2) which is then extruded, preferably with the addition of an additive (Ad) in the melt state, to prepare an extruded, preferably pelletized, aerated recycled polypropylene product (M3), which results in a polypropylene mixed color blend according to any one of claims 1 to 8.

11. A polypropylene mixed colour blend according to any one of claims 1 to 10, obtainable or obtained according to the method according to claim 9 or 10.

12. A blend comprising the polypropylene mixed color blend of any one of claims 1 to 8 and at least one virgin polypropylene and / or recycled polypropylene.

13. An article comprising the polypropylene mixed color blend of any one of claims 1 to 8 or the blend of claim 12.

14. 14. The article of claim 13, selected from the group consisting of caps, closures, bottles, containers, automotive articles, and wire and cable articles.

15. 12. Use of the polypropylene mixed color blend of any one of claims 1 to 8 and 11 in household applications, automotive applications, appliances, packaging, or wire and cable applications.

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