High purity polypropylene recovery

Abstract

The present invention relates to a polymer composition, preferably a melt treated polymer composition, comprising at least 95 wt%, based on the total weight of the polymer composition, of a post-consumer recycled polypropylene resin, said polymer composition having the following features: based on the total weight of the crystalline components of the polymer composition, at least 95 wt%, based on the total weight of the polymer composition, of the post-consumer recycled polypropylene resin; the ethylene content (C2 (CF)) of the crystalline component (CF) is in the range of [C2-3. 4] wt% to [C2-0. 2] wt%, preferably [C2-3. 0] wt% to [C2-0. 6] wt%, more preferably [C2-2. 4] wt% to [C2-1. 2] wt%, as described in the description, as determined by Crystex analysis; and a total light transmittance in the range of from 60% to 100%, preferably in the range of from 65% to 90%, more preferably in the range of from 70% to 85%, measured according to ASTM D1003-13 for a press-molded sheet of 60 mm * 60 mm * 1 mm, preferably in the range of from 60% to 100%, preferably in the range of from 65% to 90%, more preferably in the range of from 70% to 85%. The invention further relates to the use of said polymer composition for the manufacture of articles, and to corresponding articles.

Description

TECHNICAL FIELD

[0001] The present invention relates to a polymer composition, preferably a melt-processed polymer composition, comprising a post-consumer recycled polypropylene resin. The present invention further relates to the use of said polymer composition, preferably a melt-processed polymer composition, for the manufacture of an article, and to the corresponding article. BACKGROUND

[0002] The challenge of dealing with accumulated plastic waste and the corresponding environmental problems have received a lot of attention from the public and professionals. Therefore, the recycling of plastic materials has become an important issue, in which plastic waste can be turned into a resource for new plastic products. Thus, in the recycling and re-use of plastic materials, environmental and economic aspects can be combined.

[0003] Although the recycling of plastic materials has been initiated in the mid-1990s by implementing a collection system, which allowed a more targeted collection and separation of plastic materials from other household waste materials, the re-use of plastic materials derived from plastic waste is still limited. So-called post-consumer recycled (PCR) plastic materials usually contain a mixture of different plastics and a variety of contaminants. Methods have been developed to further purify post-consumer recycled (PCR) plastic materials.

[0004] Post-consumer recyclates obtained by mechanical recycling facilities involving sorting according to color and chemical structure followed by an intensive washing treatment still have some drawbacks, as the purification is limited to the surface of the polymer particles and any substances in the bulk of the particles cannot be removed. Extrusion and de- / aeration can be used to partially remove larger sized fillers and to reduce volatiles, respectively, for example by melt filtration. Mechanical recycling processes are widely known and described in, for example, WO 2022 / 200588 and WO 2022 / 200587.

[0005] However, even with the current advanced mechanical recycling technologies, the filler content, the presence of specific metals, the color, the volatiles and odor, and other properties can hinder the application of polymer materials requiring a higher purity.

[0006] Solvent-based recycling offers post-consumer recycled polymers with a higher purity grade. For example, WO 2017 / 003798 A1 discloses a method of dissolving post-consumer used polymers, wherein a polymer with a relatively low contaminant content is prepared. Further solvent-based recycling processes are disclosed in WO 2022 / 128490 A1 and WO 2022 / 128488 A1. However, these contaminant contents can still not allow the use of the recycled polymers in all applications, and there is still a need for recycled polymers with a higher purity grade.

[0007] Due to the establishment of voluntary sustainability goals by many companies, the demand for high quality recyclates is very strong and continuously increasing. In addition, upcoming regulations set targets for a certain percentage of recycled content into end products.

[0008] Therefore, there is a need for a high purity post-consumer recyclate that can be used in a variety of applications. SUMMARY

[0009] It is an object of the present invention to provide a polymer composition containing a high content of post-consumer recycled polypropylene resin that meets the above-mentioned needs.

[0010] Therefore, the present invention provides a polymer composition, preferably a melt-processed polymer composition, comprising at least 95 wt% of a post-consumer recycled polypropylene resin based on the total weight of the polymer composition, the polymer composition having the following features: an ethylene content (C2(CF)) of the crystalline fraction (CF) in the range of [C2-3.4] wt% to [C2-0.2] wt%, preferably [C2-3.0] wt% to [C2-0.6] wt%, more preferably [C2-2.4] wt% to [C2-1.2] wt%, based on the total weight of the crystalline fraction of the post-consumer recycled polypropylene resin, as determined by Crystex analysis as described in the specification; and a total light transmission in the range of 60% to 100%, preferably in the range of 65% to 90%, more preferably in the range of 70% to 85%, as measured according to ASTM D1003-13 on a compression-molded plaque of 60 mm x 60 mm x 1 mm.

[0011] Surprisingly, it was found that dissolving the (mechanically) pre-processed plastic feedstock in a dissolving solvent selected from organic solvents comprising one or more hydrocarbons having a boiling point between 75°C and 250°C to recover a purified polymer component, followed by melt processing the purified polymer component and further separating the solvent from the purified polymer component, improves the removal of impurities, thereby resulting in a polymer composition having improved optical properties, as indicated by the advantageous total light transmission of the polymer composition.

[0012] The present invention further relates to the use of the polymer composition, preferably the melt-processed polymer composition, for the manufacture of an article, and to the corresponding article. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The relationship between the ethylene content (C2) of the polypropylene resins of Examples IE1 and IE2 and the ethylene content (C2(CF)) of the crystalline fraction of the respective resins is shown and compared to various virgin PP resins. DETAILED DESCRIPTION

[0014] For the purposes of the present specification and the following claims, the term "post-consumer waste" refers to objects that have completed at least a first use cycle (or life cycle), i.e. have completed their first use. The term "virgin" denotes newly produced materials and / or objects that have not been recycled, i.e. have not undergone a first use. The term "recycled" as used herein denotes materials that have been reprocessed from "recycled waste".

[0015] The present invention provides a polymer composition comprising a post-consumer recycled polypropylene resin, preferably a melt-processed polymer composition, having a total light transmission in the range of 60% to 100%, preferably in the range of 65% to 90%, more preferably in the range of 70% to 85%, measured according to ASTM D1003-13 on a compression-molded plaque of 60 mm x 60 mm x 1 mm.

[0016] Thus, the polymer composition according to the present invention, and preferably the post-consumer recycled polypropylene resin of the polymer composition, has good optical properties, wherein the polymer composition is preferably a melt-processed polymer composition. Optical properties are an indicator of the purity grade of a material. In general, only virgin polymers can achieve good optical properties, while recycled materials cannot. The high purity grade of the post-consumer recycled polypropylene resin of the polymer composition according to the present invention enables its use in a variety of applications, wherein the polymer composition is preferably a melt-processed polymer composition. For example, it can be used in applications where contaminants can have a negative impact on the production or handling of the article. Furthermore, it can also be considered for use in applications where the recycled polymer has not yet been approved according to regulations due to the uncertainty of the content of contaminants (e.g. in the food industry). Thus, the polymer composition according to the present invention, preferably a melt-processed polymer composition, allows the use of recycled polymers in areas where their use can not yet be feasible.

[0017] Polymer composition

[0018] The present invention relates to a polymer composition, preferably a melt-processed polymer composition, such as a melt-extruded polymer composition. The polymer composition according to the present invention, preferably a melt-processed polymer composition, comprises a post-consumer recycled polypropylene resin, preferably consists essentially of a post-consumer recycled polypropylene resin.

[0019] The polymer composition according to the present application, preferably a melt- processed polymer composition, comprises at least 95 wt%, preferably at least 97 wt%, more preferably at least 98 wt%, even more preferably at least 99 wt% of post-consumer recycled polypropylene resin, based on the total weight of the polymer composition. In some embodiments, the polymer composition according to the present application, preferably a melt-processed polymer composition, comprises post-consumer recycled polypropylene resin as the sole polymer component. According to another embodiment, the polymer composition consists essentially of post-consumer recycled polypropylene resin. In this case, the post-consumer recycled polypropylene resin represents all polymer material present in the entire composition.

[0020] It is understood that low levels of additives, such as polymer stabilizers, can be present in the polymer composition, up to 5 wt%, preferably up to 3 wt%, more preferably up to 2 wt%, even more preferably up to 1 wt%, based on the total weight of the polymer composition. In one aspect of the present specification, the polymer composition consists of post-consumer recycled polypropylene resin and optionally these low levels of polymer additives. Generally, low levels of additives up to 5 wt% do not significantly alter the properties of the polymer composition. In particular, the properties described in the present application are not significantly altered by the addition. This means that the described properties, if measured directly on the post-consumer recycled polypropylene resin, generally have similar values, or in some cases even identical values, based on the total weight of the polymer composition. Examples of additives are: primary antioxidants, such as sterically hindered phenols, including octadecyl 3-(3',5'-di-tertbutyl-4-hydroxyphenyl)propionate (e.g. Irganox 1076), 2,2'-thiodiethylenebis-(3,5-di-tertbutyl-4-hydroxyphenyl)-propionate (e.g. Irganox 1330 FF), 2,5,7,8-Tetramethyl-2(4',8',12'-trimethyltridecyl)chroman-6-ol (e.g. Irganox E 201); and secondary antioxidants, such as phosphites (e.g. Irgafos 168) or phosphonites.

[0021] Preferably, the content of the compounds comprised in the post-consumer recycled polypropylene resin as described below is similar or at least not higher in the corresponding polymer composition, preferably in the melt-processed polymer composition.

[0022] Post-consumer recycled (PCR) polypropylene resin

[0023] According to the present application, a post-consumer recycled (PCR) polypropylene resin means a resin comprising at least one post-consumer recycled polypropylene, i.e. a polypropylene obtained from post-consumer waste. Preferably, the post-consumer recycled polypropylene resin comprises at least 80 wt.-% and preferably at most 100 wt.-%, for example 80 wt.-% to 99 wt.-%, preferably at least 90 wt.-%, more preferably at least 95 wt.-% of at least one post-consumer recycled polypropylene, i.e. a polypropylene obtained from post-consumer waste, as determined by Fourier Transform Infrared (FTIR) spectroscopy, based on the total weight of the post-consumer recycled polypropylene resin.

[0024] Thus, the post-consumer recycled polypropylene resin has completed at least one use cycle (or life cycle), i.e. has completed its first use. The post-consumer recycled polypropylene resin is different from virgin polypropylene resin, i.e. a newly produced material which has not yet been recycled. The post-consumer recycled polypropylene resin is also different from industrial waste, i.e. manufacturing scrap, which typically does not reach the consumer.

[0025] The post-consumer recycled (PCR) polypropylene resin of the polymer, i.e. polypropylene, composition according to the present application is preferably produced from a plastic feedstock comprising at least polypropylene, wherein the polymer composition is preferably a melt-processed polymer composition, by a process comprising one or more mechanical recycling steps and one or more recycling steps based on solvents, wherein the plastic feedstock comprises plastic waste, such as post-consumer waste, preferably consists of plastic waste, such as post-consumer waste, and the above steps are preferably combined with the melt-processing process steps discussed herein.

[0026] In general, virgin polymer materials and mechanically recycled polymer materials can be easily distinguished based on the presence of contaminants, such as limonene, fatty acids, paper and / or wood and other contaminants, or are usually easily distinguished based on their ash content. It is also possible to further distinguish polypropylene from the source of the material by the presence of non-polyolefin polymers, such as polystyrene and / or polyamide. However, current post-consumer recycled resins are comparable to virgin polypropylene to a considerable extent in many of these conventional distinguishing properties.

[0027] The post-consumer recycled polypropylene resin of the polymer composition according to the present application, preferably can be distinguished from virgin polypropylene by an ethylene content (C2(CF)) of the crystalline fraction (CF) in the range of [C2-3.4] wt% to [C2-0.2] wt%, preferably [C2-3.0] wt% to [C2-0.6] wt%, more preferably [C2-2.4] wt% to [C2-1.2] wt%, based on the total weight of the crystalline fraction of the post-consumer recycled polypropylene resin, which is determined by Crystex analysis as described herein. Herein, C2 represents the value obtained for the ethylene content of the respective polymer as further described below.

[0028] In other words, the ethylene content (C2(CF)) of the crystalline fraction (CF) is preferably in the range of [-3.4+C2] < C2(CF) < [-0.2+C2], more preferably [-3.0+C2] < C2(CF) < [-0.6+C2], most preferably [-2.4+C2] < C2(CF) < [-1.2+C2], based on the total weight of the crystalline fraction of the post-consumer recycled polypropylene resin in wt%.

[0029] Similarly, the polymer composition (preferably the melt-processed polymer composition) according to the present application can preferably be distinguished from virgin polypropylene (composition) by an ethylene content (C2(CF)) of the crystalline fraction (CF) in the range of [C2-3.4] wt% to [C2-0.2] wt%, preferably [C2-3.0] wt% to [C2-0.6] wt%, more preferably [C2-2.4] wt% to [C2-1.2] wt%, based on the total weight of the crystalline fraction of the polymer composition.

[0030] As Figure 1 It can be seen that the relationship between the ethylene content of the crystalline fraction and the ethylene content of the polymer sample differs between the recycled polypropylene resin (SbR product) and the virgin polypropylene resin.

[0031] The polymer composition (preferably the melt-processed polymer composition) according to the present application can further be distinguished from mechanically recycled polypropylene (composition) by the gamma phase content as measured by wide angle X-ray scattering (WAXS). It has been found that polypropylene recyclates obtained by solvent-based recycling processes typically contain much lower gamma phase content (as measured by WAXS) in the crystalline structure than the corresponding polypropylene recyclates obtained by mechanical recycling processes.

[0032] Preferably, the post-consumer recycled polypropylene resin comprises at least 80 wt%, more preferably at least 85 wt%, even more preferably at least 90 wt%, preferably at most 100 wt% of one or more propylene (co)polymer components, based on the total weight of the post-consumer recycled polypropylene resin, as determined by Fourier Transform Infrared (FTIR) spectroscopy. The term propylene (co)polymer components denotes propylene homopolymer components and / or propylene copolymer components.

[0033] Preferably, the polymer composition comprises at least 80 wt%, more preferably at least 85 wt%, even more preferably at least 90 wt%, preferably at most 100 wt% of one or more propylene (co)polymer components, based on the total weight of the polymer composition, as determined by Fourier Transform Infrared (FTIR) spectroscopy.

[0034] Preferably, the polymer composition comprises 0 wt% to 1 wt% of non-polyolefin polymers, as determined by Fourier Transform Infrared (FTIR) spectroscopy, based on the total weight of the polymer composition. More preferably, no polyamide (PA) and / or polystyrene (PS) polymers are detected in the polymer composition by FTIR spectroscopy. Yet more preferably, no PET and / or PVC are detected in the polymer composition by FTIR spectroscopy. Most preferably, no PA, PS, PET and PVC are detected in the polymer composition by FTIR spectroscopy.

[0035] In particular, the post-consumer recycled polypropylene resin comprises 0 wt% to 1 wt% of non-polyolefin polymers, as determined by Fourier Transform Infrared (FTIR) spectroscopy, based on the total weight of the post-consumer recycled polypropylene resin. More preferably, no polyamide (PA) and / or polystyrene (PS) polymers are detected in the post-consumer recycled polypropylene resin by FTIR spectroscopy. Yet more preferably, no PET and / or PVC are detected in the post-consumer recycled polypropylene resin by FTIR spectroscopy. Most preferably, no PA, PS, PET and PVC are detected in the post-consumer recycled polypropylene resin by FTIR spectroscopy.

[0036] The post-consumer recycled polypropylene resin as well as the polymer composition preferably comprises a mixture (e.g. a polymer blend) of one or more propylene (co)polymer components, said mixture comprising propylene homopolymer components and / or propylene copolymer components.

[0037] "Polymer blend" means a mixture of two or more components, at least one of which is a polymer. Generally, a blend can be prepared by mixing two or more components. Suitable mixing procedures are known in the art. If such a blend comprises virgin material, the virgin material is preferably polypropylene comprising at least 90 wt% of a reactor made polypropylene material and optionally polymer additives.

[0038] The expression "propylene homopolymer" means a propylene polymer consisting of at least 99.0 wt%, preferably at least 99.5 wt%, more preferably at least 99.8 wt% of propylene monomer units, based on the total weight of the propylene polymer, as determined by quantifying the 13 C{ 1 H}nuclear magnetic resonance (NMR) spectroscopy. In one embodiment, only propylene monomer units are detectable in the propylene homopolymer.

[0039] Based on its crystalline structure, the propylene homopolymer can exist as isotactic, syndiotactic, and / or atactic propylene homopolymer.

[0040] The expression "propylene copolymer" means a propylene polymer generally comprising propylene monomer units and other comonomer units, preferably ethylene comonomer units and / or one or more alpha-olefin comonomer units having 4 to 10 carbon atoms, most preferably ethylene comonomer units. Preferably, the content of propylene monomer units in the propylene copolymer is at least 70 wt%, based on the total weight of the propylene copolymer, as determined by quantifying the 13 C{ 1 H}-NMR spectroscopy; or, the content of propylene monomer units in the propylene copolymer is 70 mol%, based on the total mole content of the propylene copolymer, as determined by quantifying the 13 C{ 1 H}-NMR spectroscopy.

[0041] In some embodiments, the polymer composition comprises less than 12 wt%, more preferably less than 10 wt%, most preferably less than 9 wt%, and typically at least 0.1 wt% of ethylene propylene rubber (EPR), based on the total weight of the polymer composition, as determined by Cross Fraction Chromatography (CFC) as described herein.

[0042] In particular, the post-consumer recycled polypropylene resin comprises less than 12 wt%, more preferably less than 10 wt%, most preferably less than 9 wt%, and typically at least 0.1 wt% of ethylene propylene rubber (EPR), based on the total weight of the post-consumer recycled polypropylene resin, as determined by Cross Fraction Chromatography (CFC) as described herein.

[0043] The content of ethylene comonomer can range from 15 wt% to 50 wt%, based on the total weight of the ethylene-propylene rubber, and determined by IR detector.

[0044] The polymer composition can further comprise up to 10 wt%, more preferably up to 6 wt%, most preferably up to 4 wt%, of one or more ethylene (co)polymer components, including ethylene homopolymer components and ethylene copolymer components, comprising ethylene monomer units and one or more alpha-olefin comonomer units having 4 to 10 carbon atoms, as determined by quantification 13 C{ 1 H}-NMR spectroscopy.

[0045] In particular, the post-consumer recycled polypropylene resin comprises up to 10 wt%, more preferably up to 6 wt%, most preferably up to 4 wt%, of one or more ethylene (co)polymer components, including ethylene homopolymer components and ethylene copolymer components, comprising ethylene monomer units and one or more alpha-olefin comonomer units having 4 to 10 carbon atoms, as determined by quantification 13 C{ 1 H}-NMR spectroscopy.

[0046] In some embodiments, the polymer composition comprises: 0.1 wt% to 1.0 wt%, preferably 0.2 wt% to 0.5 wt%, of a high crystalline fraction (HCF) ethylene polymer; and / or 1.0 wt% to 5.0 wt%, preferably 2.0 wt% to 3.5 wt%, of a low crystalline fraction (LCF) ethylene polymer, based on the total weight of the polymer composition, and as determined by Cross-Fraction Chromatography (CFC) as described herein.

[0047] In particular, the post-consumer recycled polypropylene resin comprises: 0.1 wt% to 1.0 wt%, preferably 0.2 wt% to 0.5 wt%, of a high crystalline fraction (HCF) ethylene polymer; and / or 1.0 wt% to 5.0 wt%, preferably 2.0 wt% to 3.5 wt%, of a low crystalline fraction (LCF) ethylene polymer, based on the total weight of the post-consumer recycled polypropylene resin, and as determined by Cross-Fraction Chromatography (CFC) as described herein.

[0048] As the propylene (co)polymer or ethylene (co)polymer content cannot be determined directly, the weight content is determined from the equivalent ratio corrected by isotactic polypropylene (iPP) homopolymer and high density polyethylene (HDPE).

[0049] The propylene (co)polymer component preferably has a high crystallinity as defined below. However, less crystalline or non-crystalline copolymer components can also be present in the post-consumer recycled polypropylene resin, and thus also in the polymer composition.

[0050] Preferably, the polymer composition comprises 85 wt% to 95 wt%, more preferably 87 wt% to 94 wt%, most preferably 88 wt% to 93 wt% of the crystalline fraction (CF) based on the total weight of the polymer composition, as determined according to the Crystex analysis as described herein.

[0051] In particular, the post-consumer recycled polypropylene resin comprises 85 wt% to 95 wt%, more preferably 87 wt% to 94 wt%, most preferably 88 wt% to 93 wt% of the crystalline fraction (CF) based on the total weight of the post-consumer recycled polypropylene resin, as determined according to the Crystex analysis as described herein.

[0052] The less crystalline or non-crystalline copolymer components constitute the majority of the soluble fraction (SF) and, based on the total weight of the polymer composition, they are preferably present in an amount of 5 wt% to 15 wt%, more preferably 6 wt% to 13 wt%, even more preferably 7 wt% to 12 wt%, as determined according to the Crystex analysis as described herein. In particular, they are present in an amount of 5 wt% to 15 wt%, more preferably 6 wt% to 13 wt%, even more preferably 7 wt% to 12 wt%, based on the total weight of the post-consumer recycled polypropylene resin, as determined according to the Crystex analysis as described herein.

[0053] In some embodiments, the polymer composition comprises an ethylene content (C2) of 1.5 wt% to 10.0 wt%, preferably 2.0 wt% to 8.0 wt%, more preferably 2.0 wt% to 7.0 wt%, based on the total weight of the polymer composition, as determined according to the Crystex analysis as described herein.

[0054] In particular, the post-consumer recycled polypropylene resin comprises an ethylene content (C2) of 1.5 wt% to 10.0 wt%, preferably 2.0 wt% to 8.0 wt%, more preferably 2.0 wt% to 7.0 wt%, based on the total weight of the post-consumer recycled polypropylene resin, as determined according to the Crystex analysis as described herein.

[0055] In some embodiments, the polymer composition comprises an ethylene content (C2(CF)) of the crystalline fraction of 0.3 wt% to 5 wt%, preferably 0.4 wt% to 4 wt%, more preferably 0.5 wt% to 3 wt%, based on the total weight of the crystalline fraction of the polymer composition, as determined according to the Crystex analysis as described herein.

[0056] In particular, the post-consumer recycled polypropylene resin comprises an ethylene content of the crystalline fraction (C2(CF)) of 0.3 wt% to 5 wt%, preferably 0.4 wt% to 4 wt%, more preferably 0.5 wt% to 3 wt%, based on the total weight of the crystalline fraction of the post-consumer recycled polypropylene resin, determined according to the Crystex analysis as described herein.

[0057] In some embodiments, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, comprises an ethylene content of the soluble fraction (C2(SF)) of 10 wt% to 40 wt%, preferably 15 wt% to 35 wt%, more preferably 20 wt% to 30 wt%, based on the total weight of the soluble fraction of the polymer composition, determined according to the Crystex analysis as described herein.

[0058] In particular, the post-consumer recycled polypropylene resin comprises an ethylene content of the soluble fraction (C2(SF)) of 10 wt% to 40 wt%, preferably 15 wt% to 35 wt%, more preferably 20 wt% to 30 wt%, based on the total weight of the soluble fraction of the post-consumer recycled polypropylene resin, determined according to the Crystex analysis as described herein.

[0059] In some embodiments, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, comprises a soluble fraction having an intrinsic viscosity (IV(SF)) in the range of 0.8 dl / g to 3.0 dl / g, preferably 0.9 dl / g to 2.5 dl / g, more preferably 1 dl / g to 2 dl / g, determined according to the Crystex analysis as described herein.

[0060] Advantageously, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, comprises a soluble fraction (SF) having a ratio of the molecular weight of the soluble fraction (SF) to the molecular weight of the ethylene polymer (PE): Mw(SF) / Mw(PE) of more than 2, and also preferably less than 5, determined by Cross-Fraction Chromatography (CFC) as described herein. A higher Mw(SF) / Mw(PE) value indicates that the high molecular weight ethylene polymer component is purged from the composition, while the high molecular weight EPR (ethylene propylene rubber) component is retained. Due to the high intrinsic viscosity of the EPR, the composition is endowed with positive properties.

[0061] Preferably, the (weight average) molecular weight (Mw) of the soluble fraction (SF) of the polymer composition, in particular of the post-consumer recycled polypropylene resin thereof, is in the range of 100 kg / mol to 350 kg / mol, more preferably 110 kg / mol to 200 kg / mol, most preferably 120 kg / mol to 180 kg / mol, as determined by Cross-Fraction Chromatography (CFC) analysis as described herein.

[0062] Preferably, the (weight average) molecular weight (Mw) of the ethylene polymer (PE) of the polymer composition, in particular of the post-consumer recycled polypropylene resin thereof, is in the range of 20 kg / mol to 100 kg / mol, more preferably 25 kg / mol to 80 kg / mol, most preferably 30 kg / mol to 60 kg / mol, as determined by Cross-Fraction Chromatography (CFC) analysis as described herein.

[0063] The polymer composition of the present application, in particular the post-consumer recycled polypropylene resin thereof, is advantageously a near polyethylene-free composition, characterized by a low C2 content in the TREF fraction between 70 °C and 95 °C and a high PEP / EEE ratio.

[0064] In some embodiments, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, comprises a temperature rising elution fraction (TREF) fraction eluting between 70 °C and 95 °C, wherein high molar mass PE, EP copolymer and low Mw iPP are eluted with an ethylene content lower than 34 wt% C2, preferably less than 30 wt% C2, more preferably less than 25 wt% C2, even more preferably less than 16 wt% C2, and also preferably more than 2.5 wt%, as determined by Cross-Fraction Chromatography (CFC) analysis as described herein.

[0065] In some embodiments, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, has a comonomer sequence distribution ratio at ternary level PEP / EEE of more than 0.3, preferably more than 0.4, as determined by quantitative 13 C{ 1 H}NMR spectroscopy. EEE denotes a ternary ethylene block, while PEP denotes a propylene-ethylene-propylene block.

[0066] Optical and mechanical properties

[0067] The polymer composition (preferably a melt-treated polymer composition) comprising post-consumer recycled polypropylene resin according to the present invention has a beneficial balance of mechanical and optical properties, wherein the mechanical properties are particularly fracture, elongation and impact properties, and the optical properties are particularly good total luminous transmittance.

[0068] Therefore, the polymer composition according to the invention (preferably a melt-treated polymer composition) is characterized by its good mechanical properties and light transmittance.

[0069] Therefore, the total light transmittance of the polymer composition (preferably a melt-treated polymer composition, especially its post-consumption recycled polypropylene resin) is preferably in the range of 60% to 100%, more preferably in the range of 65% to 90%, and more preferably in the range of 70% to 85%, as measured according to ASTM D1003-13 for a 60mm × 60mm × 1mm molded plate.

[0070] Of particular advantage is that the polymer composition according to the invention simultaneously possesses good total light transmittance and good color values ​​(i.e., CIEL*a*b* and ΔE). This makes the polymer composition particularly suitable for a wide range of applications requiring these properties.

[0071] In some embodiments, the tensile modulus E of the polymer composition (especially its post-consumption recycled polypropylene resin) is preferably in the range of 1200 MPa to 2000 MPa, more preferably in the range of 1300 MPa to 1900 MPa, even more preferably in the range of 1400 MPa to 1800 MPa, and most preferably in the range of 1500 MPa to 1700 MPa, and is measured using a test speed of 20 mm / s according to ISO 527-1 / -2 on a compression-molded specimen of tension type 5A with a thickness of 2 mm.

[0072] In some embodiments, the polymer composition (especially its post-consumer recycled polypropylene resin) preferably has a Charpy notched impact strength of 2.0 kJ / m at 23°C. 2 Up to 7.0 kJ / m 2 Within the range, it is better at 3.0 kJ / m 2 Up to 6.0 kJ / m 2 Within the range, and even better at 3.2 kJ / m 2 Up to 5.0 kJ / m 2 Within the specified range, measurements were performed using 80 mm × 10 mm × 4 mm molded specimens prepared in accordance with EN ISO 19069-2, according to ISO 179-1 / 1eA.

[0073] Optionally or additionally, such overall performance can be expressed by the optomechanical ability.

[0074] The optomechanical ability (OMA) is understood as the ratio of the mechanical (in particular impact and flexural) behavior to the optical performance (i.e. haze), wherein the goal of the mechanical properties is to be as high as possible, while the optical performance (e.g. haze) is desired to be as low as possible. The optomechanical ability can be determined by multiplying the flexural modulus by the notched impact strength and correlating this result with the haze determined on a 1 mm plaque. Such overall performance can also be expressed by the process focused optomechanical ability (pOMA).

[0075] The optomechanical ability of the polymer composition (in particular of the post-consumer recycled polypropylene resin thereof) can be at least 50 or more, for example from 50 to 200.

[0076] In some embodiments, the process focused optomechanical ability (pOMA) of the polymer composition (in particular of the post-consumer recycled polypropylene resin thereof) can be at least 50 or more, for example from 50 to 200.

[0077] The polymer composition comprising a post-consumer recycled polypropylene resin according to the present application (preferably a melt-processed polymer composition) preferably has a beneficial balance of further mechanical properties comparable to virgin polypropylene, in particular a beneficial balance of breaking, elongation and impact properties.

[0078] In some embodiments, the tensile strength at yield (TSY) of the polymer composition (in particular of the post-consumer recycled polypropylene resin thereof) is at least 26 MPa, for example in the range of from 28 MPa to 50 MPa, preferably at least 28 MPa, more preferably at least 30 MPa, as measured according to ISO 527-1 / -2 as described herein.

[0079] In some embodiments, the polymer composition (in particular of the post-consumer recycled polypropylene resin thereof) has a bendability of more than 9, preferably more than 10, for example from 9 to 15, as calculated as described herein.

[0080] The polymer composition comprising a post-consumer recycled polypropylene resin according to the present application (preferably a melt-processed polymer composition) preferably has a beneficial dynamic mechanical property comparable to virgin polypropylene, in particular a beneficial heat distortion resistance.

[0081] In some embodiments, the polymer composition, especially the post-consumer recycled polypropylene resin thereof, has a heat distortion resistance of at least 97 °C, preferably in the range of 97 °C to 110 °C, more preferably in the range of 98 °C to 105 °C, as determined by DMTA as described herein and expressed as the temperature at which the storage modulus E' reaches 400 MPa (T(E' = 400 MPa)).

[0082] In some embodiments, the polymer composition, especially the post-consumer recycled polypropylene resin thereof, has a storage modulus (E', 90 °C) in the range of 470 MPa to 600 MPa, preferably in the range of 480 MPa to 550 MPa, as determined by DMTA at 90 °C as described herein.

[0083] In some embodiments, the polymer composition, especially the post-consumer recycled polypropylene resin thereof, has a storage modulus (E', 120 °C) in the range of 210 MPa to 350 MPa, preferably in the range of 240 MPa to 300 MPa, as determined by DMTA at 120 °C as described herein.

[0084] The polymer composition, preferably melt-processed polymer composition, comprising a post-consumer recycled polypropylene resin according to the present application preferably has advantageous dynamic mechanical properties, in particular heat distortion resistance, comparable to virgin polypropylene.

[0085] In some embodiments, the post-consumer recycled polypropylene resin, and advantageously also the polymer composition, preferably melt-processed polymer composition, has a heat distortion resistance of at least 97 °C, preferably in the range of 97 °C to 110 °C, more preferably in the range of 98 °C to 105 °C, as determined by DMTA as described herein and expressed as the temperature at which the storage modulus E' reaches 400 MPa (T(E' = 400 MPa).

[0086] In some embodiments, the post-consumer recycled polypropylene resin, and advantageously also the polymer composition, preferably melt-processed polymer composition, has a storage modulus (E', 90 °C) in the range of 470 MPa to 600 MPa, preferably in the range of 480 MPa to 550 MPa, as determined by DMTA at 90 °C as described herein.

[0087] In some embodiments, the post-consumer recycled polypropylene resin, and advantageously also the polymer composition, preferably melt-processed polymer composition, has a storage modulus (E', 120 °C) in the range of 210 MPa to 350 MPa, preferably in the range of 240 MPa to 300 MPa, as determined by DMTA at 120 °C as described herein.

[0088] contaminants

[0089] The polymer composition comprising post-consumer recycled polypropylene resin, preferably melt-processed polymer composition, according to the present application has very low levels of contaminants. This enables its use in various applications. Preferably, the metal content of the polymer composition, especially of the post-consumer recycled polypropylene resin thereof, is very low. For certain contaminants, the levels in the polymer composition, especially of the post-consumer recycled polypropylene resin thereof, are lower than in virgin polypropylene polymers. In particular, the levels of metals used in the co-catalyst are reduced.

[0090] The polymer composition of the present application preferably has a very low ash content comparable to virgin polypropylene. Preferably, the levels of other contaminants are also very low. The contaminant levels of the polymer composition are described below. The contaminant levels in the post-consumer recycled polypropylene resin are also similarly low, i.e. the same maximum levels and ranges of contaminants are comprised in the post-consumer recycled polypropylene resin.

[0091] In some embodiments, the polymer composition, preferably melt-processed polymer composition, comprising post-consumer recycled polypropylene resin has an ash content of at most 0.07 wt%, preferably at most 0.06 wt%, and more preferably at most 0.05 wt%, based on the total weight of the polymer composition, preferably melt-processed polymer composition, as determined according to thermogravimetric analysis (TGA) as described herein. In other words, the ash content is in the range of 0 wt% to at most 0.07 wt%, preferably 0 wt% to at most 0.06 wt%, and more preferably 0 wt% to at most 0.05 wt%, based on the total weight of the polymer composition, preferably melt-processed polymer composition.

[0092] In particular, the post-consumer recycled polypropylene resin has an ash content of at most 0.07 wt%, preferably at most 0.06 wt%, and more preferably at most 0.05 wt%, based on the total weight of the post-consumer recycled polypropylene resin, as determined according to thermogravimetric analysis (TGA) as described herein. In other words, the ash content is in the range of 0 wt% to at most 0.07 wt%, preferably 0 wt% to at most 0.06 wt%, and more preferably 0 wt% to at most 0.05 wt%, based on the total weight of the post-consumer recycled polypropylene resin.

[0093] Therefore, the ash content of the post-consumer recycled polypropylene resin is preferably very low, and therefore, the ash content of the polymer composition is preferably very low. The ash content is an indicator of the purity grade of the material. In general, only virgin polymers can achieve such a low ash content, while recycled materials cannot. The high purity grade of the post-consumer recycled polypropylene resin and the polymer composition according to the present application enables their use in a variety of applications. For example, they can be used in applications where contaminants can have a negative impact on the production or handling of the article. Furthermore, it can also be considered to use them in applications where the recycled polymer has not yet been approved according to regulations due to the uncertainty of the content of contaminants (for example, in the food industry). Therefore, the polymer composition (preferably the melt-processed polymer composition) according to the present application allows the use of recycled polymers in fields where their use can not have been feasible yet.

[0094] In some embodiments, the heavy metal content (w / w) of the polymer composition (preferably the melt-processed polymer composition) is less than 10 ppm, preferably less than 5 ppm, based on the total weight of the polymer composition (preferably the melt-processed polymer composition), as determined by X-ray fluorescence (XRF) spectroscopy as the sum of the metal content of cadmium (Cd), chromium (Cr), mercury (Hg) and lead (Pb). In more preferred embodiments, cadmium, chromium, mercury, and / or lead are not detected by X-ray fluorescence (XRF) spectroscopy.

[0095] In particular, the heavy metal content (w / w) of the post-consumer recycled polypropylene resin is less than 10 ppm, preferably less than 5 ppm, based on the total weight of the post-consumer recycled polypropylene resin, as determined by X-ray fluorescence (XRF) spectroscopy as the sum of the metal content of cadmium (Cd), chromium (Cr), mercury (Hg) and lead (Pb). In more preferred embodiments, cadmium, chromium, mercury, and / or lead are not detected by X-ray fluorescence (XRF) spectroscopy.

[0096] In some embodiments, the titanium (Ti) content (w / w) of the polymer composition (preferably the melt-processed polymer composition) is less than 100 ppm, preferably less than 50 ppm, more preferably less than 20 ppm, based on the total weight of the polymer composition (preferably the melt-processed polymer composition), as determined by X-ray fluorescence (XRF) spectroscopy.

[0097] In particular, the titanium (Ti) content (w / w) of the post-consumer recycled polypropylene resin is less than 100 ppm, preferably less than 50 ppm, more preferably less than 20 ppm, based on the total weight of the post-consumer recycled polypropylene resin, as determined by X-ray fluorescence (XRF) spectroscopy.

[0098] Low titanium content is an indicator of low filler (e.g. titanium dioxide) content in the polymer composition.

[0099] In some embodiments, the content of at least one of aluminum (Al), calcium (Ca) or chlorine (CI) in the polymer composition, preferably in the melt-processed polymer composition, is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, based on the total weight of the polymer composition, preferably of the melt-processed polymer composition, as determined by X-ray fluorescence (XRF) spectroscopy.

[0100] In particular, the content of at least one of aluminum (Al), calcium (Ca) or chlorine (CI) in the post-consumer recycled polypropylene resin is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, based on the total weight of the post-consumer recycled polypropylene resin, as determined by X-ray fluorescence (XRF) spectroscopy.

[0101] In one embodiment, the content of aluminum is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, for example from 0 ppm to 40 ppm, from 0 ppm to 30 ppm, or from 0 ppm to 20 ppm, respectively. In another embodiment, the content of calcium is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, for example from 0 ppm to 40 ppm, from 0 ppm to 30 ppm, or from 0 ppm to 20 ppm, respectively. In another embodiment, the content of chlorine is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, for example from 0 ppm to 40 ppm, from 0 ppm to 30 ppm, or from 0 ppm to 20 ppm, respectively. In yet another embodiment, the content of each of aluminum, calcium, chlorine is less than 40 ppm, preferably less than 30 ppm, more preferably less than 20 ppm, for example from 0 ppm to 40 ppm, from 0 ppm to 30 ppm, or from 0 ppm to 20 ppm, respectively. These contents apply to the polymer composition, in particular to the post-consumer recycled polypropylene resin.

[0102] Odour

[0103] The polymer composition, preferably the melt-processed polymer composition, according to the present application is characterized in that the odour rating (analysis according to VDA 270-B3) can be 3 or less.

[0104] Volatile and off-gassing

[0105] Preferably, in the polymer composition, preferably in the melt-processed polymer composition, in particular in the post-consumer recycled polypropylene resin, after pelletization, the content of each of the compounds selected from the group consisting of formaldehyde, limonene, benzene, styrene and toluene is below the detection limit, as determined by headspace gas chromatography / mass spectrometry (HS-GC-MS) as described herein.

[0106] Preferably, in the polymer composition, preferably in the melt-processed polymer composition, in particular in the post-consumer recycled polypropylene resin, after pelletization, the content of compounds having a boiling point below 250 °C is very low, more preferably the content of such compounds is below the detection limit, as determined by headspace gas chromatography / mass spectrometry (HS-GC-MS) as described herein.

[0107] Color

[0108] In general, one major drawback of recycled polymers is that they contain a high content of coloring components, which leads to a colored or typically grey appearance of the recycled polymers. Thus, their use is strongly limited to dark colored products or products where appearance is not relevant.

[0109] Preferably, the polymer composition, preferably the melt-processed polymer composition, according to the present application has a very low content of coloring components in its post-consumer recycled polypropylene resin.

[0110] The L*a*b* color space defined by the International Commission on Illumination (CIE) can be used to express the color of a polymer. It is modeled after the color-opponent theory, which states that two colors cannot be red and green at the same time, or yellow and blue at the same time. L* represents the lightness, a* is the red / green coordinate, and b* is the yellow / blue coordinate. The delta of L*(Delta L*), a*(Delta a*) and b*(Delta b*) can be positive or negative. However, the total difference Delta E (Delta E, also known as Euclidean distance) is always positive.

[0111] The polymer composition, in particular the post-consumer recycled polypropylene resin thereof, has advantageously an L* value in the CIE L*a*b* color space of at least 75, preferably from 86 to 97, more preferably from 89 to 97, for example from 90 to 97, as determined according to ISO 11664-4.

[0112] In some embodiments, the polymer composition has a color difference Delta E compared to a reference background of less than 7.5, preferably less than 7.0, for example less than 6 or even less than 5.5, as determined according to ISO 11664-4 and using the following equation:

[0113] Delta E = (DL 2+ Da 2 + Db 2 ) 0.5 = [(L* - L ref ) 2 + (a* - a ref ) 2 + (b* - b ref ) 2 ] 0.5

[0114] wherein the values of the reference background are: L ref = 96.01, a ref = -0.29, b ref = 1.79.

[0115] In some embodiments, the post-consumer recycled polypropylene resin has a color difference AE as defined above of less than 6, preferably less than 5.5, more preferably less than 5.

[0116] The color difference represents the color intensity of a component and is defined as the numerical comparison of the color of a component to a reference background (here a background panel with L ref = 96.01, a ref = -0.29, b ref = 1.79. This represents the difference in absolute color coordinates (CIEL*a*b* color space), called delta (D or D).

[0117] In some embodiments, the polymer composition, especially the post-consumer recycled polypropylene resin thereof, has a CIEL*a*b* color space of:

[0118] L* is from 86 to 97, preferably from 89 to 97, for example from 90 to 97;

[0119] a* is from -0.5 to 0.0;

[0120] b* is from 0.0 to 10.0, preferably from 0.0 to 5.0.

[0121] In the above embodiments, the color difference AE is very low and the composition appears white. The L* value represents the lightness or brightness of the composition, a high L* value indicating that the composition is very bright. Accordingly, the respective polymer compositions having a low color difference AE and / or a high L* value have a white and / or bright appearance comparable to virgin propylene polymers. Thus, they are suitable for use in white or light-colored articles where appearance is important.

[0122] In some embodiments, the polymer composition, in particular the post-consumer recycled polypropylene resin thereof, has a melt flow rate MFR2 in the range of 10 to 40 g / 10 min, preferably 12 to 36 g / 10 min, more preferably 15 to 30 g / 10 min, determined according to ISO 1133 at a load of 2.16 kg and at 230 °C.

[0123] The polymer composition, preferably the melt-processed polymer composition, can be provided in any of the embodiments as described above.

[0124] Process for the preparation of a post-consumer recycled (PCR) polypropylene resin

[0125] Plastic feedstock

[0126] The post-consumer recycled polypropylene resin as described herein can be obtained from a plastic feedstock comprising at least polypropylene, the plastic feedstock comprising, preferably consisting of, plastic waste, such as post-consumer waste.

[0127] The plastic feedstock can comprise a mixture of polymers, in particular a mixture of polyolefins, more in particular a mixture of polypropylene with other polyolefins and / or other polymers, such as polyethylene (PE), polystyrene (PS), polyamide (PA), polyvinyl chloride (PVC), expanded polystyrene (EPS), and / or polyethylene terephthalate (PET); additives for the formulation of one or more plastic materials; and impurities related to the use, originating from the life cycle of the materials and plastic objects and / or from the waste collection and sorting circuit, which compounds are collectively referred to as impurities. The plastic feedstock can further comprise other contaminants originating from other components of the original plastic objects, such as paper, cardboard, wood, textiles, metals, glass, sand, etc.

[0128] Hence, the plastic feedstock can comprise impurities. The plastic feedstock can comprise at most 50 wt% of impurities, preferably at most 20 wt% of impurities, more preferably at most 15 wt%, such as 1 to 10 wt% of impurities, based on the total weight of the plastic feedstock. One specific example of impurities comprised in the plastic feedstock are additives. Additives used in plastics are organic or inorganic compounds, such as fillers, colorants, pigments, plasticizers, modifiers, flame retardants, etc.

[0129] In particular, the plastic feedstock comprises polyolefins, including polypropylene (PP), polyethylene (PE) and copolymers thereof, in particular mixtures of polyolefins. According to the present application, the plastic feedstock typically comprises at least 60 wt.-%, preferably at least 80 wt.-%, more preferably at least 85 wt.-%, such as 80 wt.-% to 90 wt.-%, of polyolefins, based on the total weight of the plastic feedstock. The plastic feedstock preferably comprises at least 60 wt.-%, preferably at least 80 wt.-%, more preferably at least 85 wt.-%, such as 80 wt.-% to 90 wt.-%, of polypropylene, based on the total weight of the plastic feedstock.

[0130] Process for the preparation

[0131] The polymer composition (preferably melt-processed polymer composition) comprising a post-consumer recycled (PCR) polypropylene resin according to the present application can be prepared from a plastic feedstock as described above by a recycling process comprising one or more solvent-based recycling (SbR) process steps in combination with one or more mechanical recycling process steps.

[0132] Accordingly, the present application also relates to a polymer composition (preferably melt-processed polymer composition) comprising a post-consumer recycled polypropylene resin as defined herein in terms of its properties, wherein the polymer composition is obtained or obtainable from a plastic feedstock by a recycling process comprising the following steps:

[0133] M) pre-treating the plastic feedstock by a mechanical recycling process comprising sieving; sorting by at least one of polymer type, polymer article form and / or color; shredding; and optionally cleaning (e.g. washing) of the plastic feedstock to obtain a pre-treated plastic feedstock, and optionally melting of the pre-treated plastic feedstock;

[0134] S) solvent-based recycling of the pre-treated, optionally melted, plastic feedstock to obtain the post-consumer recycled polypropylene resin, preferably by dissolving the plastic feedstock comprising polypropylene in a solvent and separating the undissolved components and soluble impurities, wherein step S) comprises:

[0135] S-a) a dissolving step, wherein the pre-treated plastic feedstock is contacted with a dissolving solvent at a dissolving temperature of 100 °C to 300 °C and a dissolving pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one crude polymer solution (preferably one crude polymer solution), wherein the dissolving solvent is selected from organic solvents comprising one or more hydrocarbons having a boiling point between 75 °C and 250 °C to obtain at least one crude polymer solution;

[0136] S-b) an optional adsorption step, carried out by contacting the crude polymer solution obtained from step S-a) with at least one adsorbent at a temperature of from 100 °C to 300 °C and a pressure of from 1.0 MPa abs to 20.0 MPa abs, to obtain at least one refined polymer solution; and

[0137] S-c) a step of recovering the polymer from the at least one crude polymer solution of step S-a) or from the at least one refined polymer solution to obtain at least one solvent component and one purified polymer component; and

[0138] C) subjecting the post-consumer recycled polypropylene resin obtained from step S) to a melt treatment, wherein step C) comprises:

[0139] C-a) further separating solvent from the purified polymer component; and

[0140] C-b) subjecting the purified polymer component to a melt treatment to obtain the polymer composition of the present application.

[0141] All definitions, embodiments and further features described above for the post-consumer recycled polypropylene resin and the polymer composition of the present application apply equally to the post-consumer recycled polypropylene resin and the polymer composition obtained or obtainable by one or more recovery process steps.

[0142] Throughout the present disclosure, pressures are indicated as absolute pressures (abs).

[0143] Advantageously, the method comprises the following steps:

[0144] M-a) providing a plastic feedstock comprising at least polypropylene, the plastic feedstock comprising plastic waste, such as post-consumer waste, preferably consisting of plastic waste, such as post-consumer waste;

[0145] M-b) subjecting the plastic feedstock to a sieving to produce a sieved plastic waste material comprising at least polypropylene, the plastic waste material having only objects with a longest dimension within a defined range, such as from 30 mm to 400 mm;

[0146] M-c) subjecting the sieved plastic waste material to a sorting by one or more sorting systems, wherein the sieved waste polymer material is sorted at least according to polymer type, polymer article form and / or color, thereby producing a sorted polypropylene recycling material and feeding it to step M-d) and subsequent steps;

[0147] M-d) comminuting the sorted polypropylene recyclate to form a flaked polypropylene recyclate stream, wherein the flaked material has preferably a longest dimension of 2.5 mm to 20 mm, to obtain a pre-treated plastic feedstock;

[0148] S-a) a dissolving step comprising contacting the pre-treated plastic feedstock with a solvent to obtain at least one crude polymer solution; followed by

[0149] S-E1) optionally separating off insoluble material to obtain at least one clarified polymer solution and one insoluble component;

[0150] S-b) a step of adsorbing impurities by contacting with an adsorbent solid to obtain at least one refined polymer solution;

[0151] S-c) a step of recovering the polymer to obtain at least one solvent component and one purified polymer component;

[0152] C-a) further separating solvent from the purified polymer component; and

[0153] C-b) subjecting the purified polymer component to a melt treatment, preferably melt extrusion and / or pelletization, wherein additives are preferably added in the melt state, to obtain a polymer composition of a (preferably melt extruded and / or pelletized) polypropylene resin comprising post-consumer recycled.

[0154] Mechanical recycling pre-treatment M)

[0155] Primary pre-treatment of a plastic feedstock comprising at least polypropylene by a mechanical recycling process, the mechanical recycling process preferably comprising the following steps:

[0156] M-a) providing a plastic feedstock comprising polypropylene, the plastic feedstock comprising, preferably consisting of, plastic waste, such as post-consumer waste;

[0157] M-b) sieving the plastic feedstock to produce a sieved plastic waste material comprising polypropylene, the plastic waste material having only objects with a longest dimension within a defined range;

[0158] M-c) sorting the sieved plastic waste material by one or more sorting systems, wherein the sieved waste polymer material is sorted at least according to polymer type, polymer article form, and / or color, thereby producing a sorted polypropylene recyclate, and sending it to step M-d) and subsequent steps;

[0159] M-d) comminuting the sorted polypropylene recyclate to form a flaked polypropylene recyclate stream, wherein the flaked material has a longest dimension preferably of 2.5 mm to 20 mm, to obtain a pre- treated flaked polypropylene recyclate;

[0160] M-e) optionally, cleaning the pre-treated flaked polypropylene recyclate one or more times with a gaseous and / or aqueous cleaning medium, whereby the flaked material is separated from the medium applying the principle of gravity, to obtain a cleaned and pre-treated polypropylene recyclate;

[0161] M-f) optionally, separating the cleaned and pre-treated polypropylene recyclate into a light fraction and a heavy fraction polypropylene recyclate, to obtain a pre-treated heavy fraction polypropylene recyclate; and

[0162] M-g) optionally, further sorting the pre-treated heavy fraction polypropylene recyclate, or, in the absence of step M-f), sorting the cleaned and pre-purified polypropylene recyclate, by one or more optical sorters comprising NIR and / or optical sensors, to sort for one or more target polypropylenes by removing any flaked material containing material other than the one or more target polypropylenes and / or flaked material of an undesired color such as natural color, black color, etc., to yield a further purified and pre-treated polypropylene recyclate;

[0163] M-h) optionally, melt-extruding and optionally pelletizing the pre-treated polypropylene material in flaked form obtained from the last executed step of steps M-d) to M-g), to obtain a melt-extruded, optionally pelletized, pre-treated polypropylene recyclate.

[0164] The melt-extruded, optionally pelletized, pre-treated polypropylene recyclate, or, in the absence of step M-h), the further purified and pre-treated polypropylene recyclate, or, in the absence of step M-g) and the subsequent steps, the pre-purified heavy fraction polypropylene recyclate, or, in the absence of step M-f) and the subsequent steps, the cleaned and pre-treated polypropylene recyclate, or, in the absence of step M-e) and the subsequent steps, the pre-treated flaked polypropylene recyclate, can be used as plastic feedstock for the above solvent-based recycling steps.

[0165] As mentioned above, the pre-treated polypropylene recyclate is preferably fed as a melt to the dissolving step S-a) of the solvent-based recycling step, thus, the pre-treated polypropylene recyclate in sheet or melt-extruded form, such as pellets, is melted before being fed to the dissolving step S-a). The temperature of the molten polypropylene feed is preferably the dissolving temperature in step S-a) or higher. More preferably, the temperature of the molten polypropylene feed is higher than the temperature in step S-a). The melt feeding can be done in a continuous manner, as the melt feed can be pressurized to match the pressure in the dissolving step. However, a batch operation is also feasible, but less ideal.

[0166] Step M-b) of sieving the plastic feedstock

[0167] According to the present application, the pre-treatment of the plastic feedstock comprises a step M-b) of sieving the plastic feedstock. The sieving is done to remove oversized and undersized components to obtain a sieved plastic recyclate having only objects with a longest dimension in a defined range, for example up to 400 mm. Preferably, the longest dimension is in the range of 30 mm to 400 mm, more preferably in the range of 50 mm to 100 mm.

[0168] Step M-c) of sorting the sieved plastic waste material

[0169] According to the present application, the pre-treatment of the plastic feedstock comprises a step M-c) of sorting the sieved plastic waste material by one or more sorting systems, wherein the sieved waste polymer material is sorted according to at least one of polymer type, polymer article form and / or color, thereby producing a pre-treated polypropylene recyclate stream.

[0170] Preferably, the sorting system comprises near infrared (NIR) and / or optical sensors, wherein the sorting is performed at least according to polymer type, polymer article form and / or color, thereby producing a sorted polypropylene recyclate and feeding it to step M-d) and subsequent steps. In step M-c), the sieved plastic waste material is preferably sorted at least according to color and, optionally, also according to polyolefin type and / or article form. The sorted polypropylene material is preferably enriched in polypropylene components and can comprise any desired mixture of polypropylene objects, which are colored and / or uncolored, flexible and / or rigid.

[0171] The term "article form" as used herein refers to the shape and form of the articles present in the waste polymeric material. Such articles can be present in the form of films, bags and pouches, which can be considered as flexible articles, and in the form of molded articles, such as food containers, skin care containers and plastic bottles, which can be considered as rigid articles, in particular. Commercial optical sorters, such as Tomra Autosort, RTT Steinert Unisort and Redwave Pellenc, are capable of separating so-called rigid articles from so-called flexible articles by their aerodynamic properties (i.e. air flow is typically applied to the stream and those rigid articles will fall with a different arc than flexible articles), converting the stream containing such articles into a so-called rigid stream and a flexible stream.

[0172] In the sorting step M-c), non-polypropylene materials comprising polystyrene, polyamide, polyethylene, metal, paper and wood are preferably sorted out.

[0173] In the sorting step M-c), white and natural color waste materials are preferably sorted out, so that essentially only non-white and / or non-natural color waste materials of the least optimal direct re-use remain in the sorted polypropylene recycle stream(s). In this context, "natural" means that the object has a natural color. This means that the object essentially does not contain pigments (including carbon black) or colorants, such as dyes or inks. On the other hand, "white" indicates that the object contains a white pigment.

[0174] Step M-d) of shredding the sorted polypropylene recycle stream

[0175] According to the present application, the pre-treatment of the plastic feedstock comprises a step M-d) of shredding the sorted polypropylene recycle material to form a flaked polypropylene recycle stream. Preferably, the longest dimension of the flaked material is from 2.5 mm to 20 mm, more preferably from 5 mm to 15 mm.

[0176] The resulting pre-treated flaked polypropylene recycle material is suitable for use in a solvent-based recycling process as pre-treated plastic feedstock, or for use in step M-e) and subsequent steps. Such sorted polypropylene material comprises any homogeneous mixture of colored and uncolored polypropylene objects, as well as non-homogeneous mixtures of flexible and rigid polypropylene objects.

[0177] Step M-e) of cleaning the flaked polypropylene recycle stream

[0178] According to the present application, the pre-treatment of the plastic feedstock comprises the step M-e) of cleaning the flaky polypropylene recyclate one or more times with a gaseous and / or aqueous cleaning medium, whereby the flaky material is separated from the medium applying the principle of gravity to produce a cleaned polypropylene recyclate to obtain a pre-treated polypropylene recyclate stream.

[0179] The produced pre-treated and cleaned polypropylene recyclate is suitable for use in a solvent-based recycling process as pre-treated plastic feedstock or for use in step M-f) and subsequent steps.

[0180] The step M-e) preferably comprises:

[0181] M-e1 ) washing the flaky polypropylene recyclate one or more times with an aqueous washing solution to obtain a suspended polypropylene recyclate and removing the aqueous washing solution and optionally any material not floating on the surface of the aqueous washing solution from the suspended polypropylene recyclate to produce a washed polypropylene recyclate stream; and

[0182] M-e2) drying the washed polypropylene recyclate stream to obtain a dried polypropylene.

[0183] The step M-f) of separating the pre-treated polypropylene recyclate stream

[0184] According to the present application, the pre-treatment of the plastic feedstock optionally comprises the step M-f) of separating the optionally cleaned, pre-treated polypropylene recyclate into a light fraction and a heavy fraction polypropylene recyclate stream. Preferably, the separation is performed with an air classification device. Alternatively, the separation can be performed based on the aerodynamic properties of the particles, e.g. flaky material, such as separating light and thin flexible flaky material from heavy and thick rigid flaky material. In the sorting step M-f), preferably, light and thin flexible flaky material is sorted out, such that essentially only rigid polypropylene objects are retained in the sorted polypropylene recyclate stream. Preferably, the further sorted and pre-purified polypropylene recyclate comprises from 65 wt% to 100 wt% of rigid polypropylene based on the total amount of the pre-purified polypropylene recyclate.

[0185] The produced pre-treated heavy fraction polypropylene recyclate is suitable for use in a solvent-based recycling process as pre-treated plastic feedstock or for use in step M-g) and subsequent steps. This sorted polypropylene material comprises any mixture of colored and uncolored polypropylene articles, which is rich in rigid polypropylene objects.

[0186] The step M-g) of further sorting

[0187] According to the present application, the pre-treatment of the plastic feedstock optionally comprises a step M-g) of further sorting the heavy component polypropylene recyclate, or, in the absence of step M-f), further sorting the pre-treated polypropylene recyclate, by one or more optical sorters with NIR and / or optical sensors to sort one or more target polypropylenes. In the sorting step M-g), preferably one or more sheet-like materials containing materials other than the target polypropylenes and / or sheet-like materials having an undesired color (e.g. natural color, black color, etc.) are removed to produce a further purified and pre-treated polypropylene recyclate stream.

[0188] The produced further purified and pre-treated polypropylene recyclate is suitable for use in a solvent-based recycling process as pre-treated plastic feedstock, or for step M-h) and subsequent steps.

[0189] The step M-h) of melt-extrusion

[0190] According to the present application, the pre-treatment of the plastic feedstock optionally comprises a step M-h) of melt-extruding the pre-treated polypropylene material in sheet form. The melt-extruded plastic feedstock can optionally be pelletized. Step M-h) provides the pre-treated polypropylene material in melt-extruded form, optionally in pellets.

[0191] Step M-h) is preferably carried out in an extruder, which can be a single-screw extruder or a twin-screw extruder, wherein one or more loss-in-weight (LIW) feeders can be used, but also so-called pre-conditioning unit (PCU) feeding, which is well known to the person skilled in the art. The dimensionless throughput Q on this extruder can be calculated by the following formula:

[0192] Q = tr [kg / s] / (md [kg / m 3 * sd [m] * ss [s-1])

[0193] wherein tr is the throughput rate of the extruder; sd is the screw diameter; ss is the screw speed, which is 0.75 to 0.20, preferably 0.10 to 0.15.

[0194] The target melt temperature is 190 °C to 270 °C, preferably 200 °C to 250 °C, even more preferably 200 °C to 230 °C.

[0195] The pre-treated polypropylene material can optionally be degassed to remove moisture and reduce VOCs during its extrusion.

[0196] Degassing can be performed via up to three (in particular two) degassing ports, for example, one degassing port for top degassing and one degassing port for side degassing, which form part of the extruder. The pressure at the degassing ports can be in the range of 0.5 kPa abs to 75 kPa abs, preferably 1 kPa abs to 50 kPa abs, even more preferably 1 kPa abs to 10 kPa abs, which can be achieved by a suitable vacuum system comprising one or more vacuum pumps.

[0197] The melt-extruded and pre-treated polypropylene material can optionally be melt- filtered downstream of the extruder.

[0198] The melt-filtering can be performed with a continuous melt-filtering device, for example, the so-called Laserfilter of Erema or the Ettlinger / Maag ERF filter, or the Britas belt filter. The filtering level is typically in the range of 50 pm to 500 pm, preferably 50 pm to 250 pm, even more preferably 50 pm to 150 pm.

[0199] Optionally, the pressure for the melt-filtering is provided by one or more gear melt pumps as known to the person skilled in the art, which allow for an efficient pressurization at low energy input, thereby reducing the risk of melt temperature and polymer degradation.

[0200] The produced melt-treated (preferably melt-extruded and / or optionally pelletized) pre-treated polypropylene recyclate is suitable for a solvent-based recycling process.

[0201] The pre-treated polypropylene recyclate has a polypropylene content of higher than 90 %, preferably higher than 95 %, based on the total weight of the pre-treated polypropylene recyclate.

[0202] The pre-treated polypropylene recyclate can still contain up to 1.5 wt% of inorganic contaminants, for example, talc, chalk, Ti02, and pigments; up to about 5 wt% of polyethylene; and small amounts, for example, below 0.4 wt% of other polymers such as PA, PET, EVA, or PVC and odor active substances such as limonene, n-hexanal, toluene, and other odor active substances.

[0203] The content of polypropylene and contaminants in the pre-treated polypropylene recyclate can be analyzed using a NIR sheet material analyzer before the material is subjected to the solvent-based recycling process.

[0204] Solvent-based recycling process S)

[0205] The post-consumer recycled polypropylene resin according to the present application is obtained by a recycling process comprising a solvent-based recycling process S) after the mechanical recycling process M) as described above, for recycling a plastic feedstock comprising polypropylene, said plastic feedstock comprising plastic waste such as post-consumer waste, by dissolving the polypropylene in a solvent under specific temperature and pressure conditions, optionally followed by contacting the resulting polymer solution with a sorbent solid. Generally, the dissolving solvent has to be able to dissolve the polyolefin, in particular polypropylene. Therefore, preferably, the dissolving solvent is a non-polar solvent or a mixture thereof. Thus, the solvent is preferably a hydrocarbon or a mixture of hydrocarbons. More preferably, the dissolving solvent is a paraffinic solvent or a mixture of paraffinic solvents ("Similia similibus solventum") due to the paraffinic nature of polyolefins.

[0206] Preferably, the solvent-based recycling process S) for purifying the pre-treated plastic feedstock comprises and preferably consists of:

[0207] S-a) a dissolving step as described above, comprising contacting the pre-treated plastic feedstock obtained from the mechanical recycling process with a solvent to obtain at least one crude polymer solution; followed by

[0208] S-E1) an optional step of separating off insoluble material to obtain at least one clear polymer solution and one insoluble component;

[0209] S-E2) an optional washing step by contacting with a concentrated solution to obtain at least one washing effluent and one washed polymer solution;

[0210] S-E3) an optional extraction step by contacting with an extraction solvent to obtain at least one extracted polymer solution and one waste solvent;

[0211] S-b) a step of adsorbing impurities by contacting with a sorbent solid to obtain at least one refined polymer solution; and finally

[0212] S-c) a step of recovering the polymer (from the at least one refined polymer solution) to obtain at least one solvent component and one purified polymer component.

[0213] As an example, the solvent-based recycling process S) comprises:

[0214] S-a) a dissolving step comprising contacting the plastic feedstock with a dissolving solvent selected from at least one organic solvent comprising one or more hydrocarbons having a boiling point between 75 °C and 250 °C at a dissolving temperature of 100 °C to 300 °C and a dissolving pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one crude polymer solution;

[0215] S-b) an adsorbing step by contacting the crude polymer solution obtained from step S-a) with at least one adsorbent at a temperature of 100 °C to 300 °C and a pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one refined polymer solution; followed by

[0216] S-c) a step of recovering the polymer (from the at least one refined polymer solution) to obtain at least one solvent component and one purified polymer component.

[0217] As a preferred example, the solvent-based recovery process step S) comprises and preferably consists of:

[0218] S-a) a dissolving step comprising contacting the plastic feedstock with a dissolving solvent selected from at least one organic solvent comprising one or more hydrocarbons having a boiling point between 75 °C and 250 °C at a dissolving temperature of 100 °C to 300 °C and a dissolving pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one crude polymer solution;

[0219] S-E1) a step of separating insoluble matter to obtain at least one clear polymer solution and one insoluble component;

[0220] S-E2) an optional washing step by contacting with a concentrated solution to obtain at least one washing effluent and one washed polymer solution;

[0221] S-E3) an optional extraction step by contacting with an extraction solvent to obtain at least one extracted polymer solution and one waste solvent;

[0222] S-b) an adsorbing step by contacting the clear polymer solution obtained from step S-E1), or the optionally washed polymer solution from step S-E2), or the extracted polymer solution from step S-E3), with at least one adsorbent at a temperature of 100 °C to 300 °C and a pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one refined polymer solution; followed by

[0223] S-c) recovering the polymer (from the at least one refined polymer solution) to obtain at least one solvent component and one purified polymer component.

[0224] dissolution step S-a)

[0225] According to the present application, the process comprises a dissolution step S-a) in which the pre-treated plastic feedstock is contacted with a dissolution solvent at a dissolution temperature comprised between 100°C and 300°C and a dissolution pressure comprised between 1.0 MPa abs and 20.0 MPa abs to obtain at least one, preferably one, crude polymer solution. In particular, this step advantageously enables the dissolution of at least a part of the polymer, and preferably of the whole polymer, which is preferably polypropylene.

[0226] The term "dissolution" is understood to mean any phenomenon leading to at least one polymer solution, i.e. a liquid comprising a polymer dissolved in a solvent, and more particularly in a dissolution solvent. The person skilled in the art is perfectly aware of the phenomena involved in the dissolution of a polymer and at least include among them the mixing, the dispersion, the homogenization and the disentangling of the polymer chains, and more particularly of the thermoplastic chains.

[0227] During and at the end of the dissolution step S-a), the pressure and temperature conditions are such that at least a part, and preferably the whole, of the dissolution solvent can be kept in liquid form; while the soluble components of the feedstock, in particular the target polymer, preferably the target thermoplastic, and preferably the target polypropylene, and at least a part of the impurities, are advantageously at least partially, and preferably completely, dissolved. The contact between the dissolution solvent and the pre-treated plastic feedstock enables the at least partial, and preferably complete, dissolution of the polymer of the pre-treated plastic feedstock in the dissolution solvent, which can be carried out in one line and / or in one device and / or between two devices. Thus, the step S-a) advantageously involves at least one dissolution device, and optionally at least one feedstock preparation means, mixing means and / or conveying means. These devices and / or means can be, for example, static mixers, extruders, pumps, "reactors" (e.g. stirred vessels), co- or counter-current columns, or combinations thereof with lines and devices. The means for conveying, in particular of fluids (e.g. gases, liquids or solids), are well known to the person skilled in the art. In a non-limiting manner, the conveying means can comprise compressors, pumps, extruders, vibrating tubes, endless screws or valves. These devices and / or means can also comprise or be combined with heating systems (e.g. ovens, heat exchangers, tracings, etc.) necessary to achieve the conditions required for the dissolution.

[0228] At least the pretreated plastic feedstock, in particular in the form of one or more streams of pretreated plastic feedstock, and the solvent for dissolution, in particular in the form of one or more streams of solvent for dissolution, are fed to the dissolving step S-a), advantageously by means of one or more conveying devices. The one or more streams of pretreated plastic feedstock can be different from the one or more streams of solvent for dissolution. Part or all of the plastic feedstock can also be fed to step S-a) as a mixture with part or all of the solvent for dissolution, the remaining solvent and / or feedstock being fed separately to step S-a) where appropriate. During the contacting of the pretreated plastic feedstock with the solvent for dissolution, the solvent for dissolution is advantageously at least partially, and preferably entirely, in liquid form; while the pretreated plastic feedstock comprising polymer, in particular thermoplastic, such as polyolefin, in particular polypropylene, can be in solid or liquid form, optionally comprising suspended solid particles. The pretreated plastic feedstock can also optionally be injected into the dissolving device as a mixture with the solvent for dissolution in the form of a suspension in the solvent for dissolution, the preparation and injection of the suspension being continuous or batchwise.

[0229] Preferably, step S-a) involves at least one extruder and a dissolving device. In this case, the pretreated plastic feedstock is fed to the extruder so that at the outlet of the extruder, at least part, and preferably all, of the target polymer, in particular the target polypropylene comprised in the feedstock, is in molten form. The pretreated plastic feedstock is then injected into the dissolving device in at least partially molten form. The pretreated plastic feedstock at least partially in molten form can also be pumped by means of a pump dedicated to viscous fluids, generally known as a melt pump or gear pump. The advantage of the pretreated plastic feedstock being (at least partially) in molten form is that the pretreated plastic feedstock dissolves more quickly and uniformly in the solvent. This makes it possible to reduce the residence time in the dissolving step and to facilitate the dissolution. In addition to the melt pump, a filtering device can also be used at the outlet of the extruder to filter the pretreated plastic feedstock at least partially in molten form, in order to remove the coarsest particles; generally, the mesh size of this filter is between 10 microns and 1 millimeter, preferably between 20 microns and 200 microns. Preferably, step S-a) involves an extruder, into which the solvent for dissolution is advantageously injected at several points in order to promote shearing, thereby promoting the intimate mixing between the solvent for dissolution and the pretreated plastic feedstock, which facilitates the dissolution of the polymer, in particular the polypropylene.

[0230] The solvent used for the dissolving step S-a) is an organic solvent or a mixture of organic solvents. Preferably, the solvent used for the dissolving is selected from organic solvents comprising and preferably consisting of one or more hydrocarbons having a boiling point in the range of 75 °C to 250 °C, preferably 80 °C to 220 °C, more preferably 80 °C to 180 °C. Solvents having a higher boiling point generally require a lower process pressure, which is advantageous in terms of energy consumption. Furthermore, lower process pressures are preferred as they enable a more secure process control. The boiling point of the solvent used for the dissolving is to be understood as the boiling point of the solvent used for the dissolving at atmospheric pressure, in particular equal to 0.1 MPa. The solvent used for the dissolving comprises and preferably consists of one or more hydrocarbons, preferably one or more alkanes, containing 6 to 12 carbon atoms, in particular 6 to 10 carbon atoms, for example selected from cyclohexane and heptane isomers.

[0231] In some embodiments, the solvent used for the dissolving comprises or preferably consists of at least one n-alkane selected from C7, C8, C9 and C10 or any mixture thereof. In some embodiments, the solvent used for the dissolving comprises or consists of at least one cycloalkane selected from C6, C7, C8, C9 and C10 or any mixture thereof. In some embodiments, the solvent used for the dissolving comprises or consists of at least one isoalkane selected from C7, C8, C9 and C10 or any mixture thereof. In some embodiments, the solvent used for the dissolving comprises or consists of at least one n-alkane, preferably selected from C7, C8, C9, C10 and mixtures thereof, at least one cycloalkane, preferably selected from C6, C7, C8, C9, C10 and mixtures thereof, and / or at least one isoalkane, preferably selected from C7, C8, C9, C10 and mixtures thereof.

[0232] Preferably, the solvent for dissolution is an organic solvent, preferably a hydrocarbon, having a critical temperature comprised between 90°C and 400°C, preferably between 200°C and 390°C, more preferably between 250°C and 350°C; and a critical pressure comprised between 1.5 MPa abs and 5.0 MPa abs, preferably between 2.0 MPa abs and 4.3 MPa abs, more preferably between 2.4 MPa abs and 4.2 MPa abs. According to a specific embodiment, the solvent for dissolution has a boiling point greater than 75°C, preferably comprised between 80°C and 220°C, more preferably between 80°C and 180°C, and / or said solvent comprises and preferably consists of an alkane containing at least 7 carbon atoms. Advantageously, said dissolution is carried out at a dissolution temperature comprised between 100°C and 300°C and a dissolution pressure comprised between 1.0 MPa abs and 20.0 MPa abs. More specifically, the temperature and pressure are gradually varied from ambient conditions throughout step S-a), i.e. the temperature of the pretreated plastic feedstock is gradually varied from between 10°C and 30°C and atmospheric pressure (0.1 MPa) until the dissolution conditions, more specifically the dissolution temperature and dissolution pressure, are reached. In particular, the dissolution temperature is comprised between 100°C and 300°C, preferably between 150°C and 250°C, and the dissolution pressure is comprised between 1.0 MPa abs and 20.0 MPa abs, preferably between 1.5 MPa abs and 15.0 MPa abs, more preferably between 2.0 MPa abs and 10.0 MPa abs. Very advantageously, at the end of the dissolution step S-a), the dissolved polymer stream is at the dissolution temperature and dissolution pressure. According to a specific embodiment of the dissolution step S-a), the dissolution pressure is comprised between 1.5 MPa abs and 2.4 MPa abs, preferably between 1.7 MPa abs and 2.2 MPa abs. In this very specific embodiment, water possibly present in the pretreated plastic feedstock (in the case of a wet plastic feedstock) can be subsequently evaporated and removed during and / or prior to dissolution, for example, in particular from vents located on the dissolution line and / or equipment, in particular vents on the extruder. When this specific embodiment of the dissolution step S-a) is performed, the process for treating a plastic feedstock according to the present application does not comprise the optional step S-E2) of washing using a concentrated solution, in particular a water solution. Limiting the temperature in step S-a) to less than or equal to 300°C, preferably less than or equal to 250°C, prevents or limits the thermal degradation of the polymer, in particular of polypropylene. Preferably, the dissolution temperature is higher than or equal to the melting point of the polymer, in particular of the thermoplastic, more particularly of polypropylene, to facilitate its dissolution. Preferably, the temperature in the dissolution step S-a) is less than or equal to the critical temperature of the solvent for dissolution, to avoid the formation of a supercritical phase that would disrupt the dissolution during the dissolution step S-a).At the same time, the dissolution pressure is greater than the saturation vapor pressure of the dissolving solvent at the dissolution temperature, so that the dissolving solvent is at least partially and preferably entirely in liquid form at the dissolution temperature. Advantageously, the dissolution pressure is greater than or equal to the critical pressure of the dissolving solvent, so as to be able to carry out the recovery step S-c) in particular under conditions in which at least a portion of the solvent is in supercritical form, without the need to substantially increase the pressure between step S-a) (in particular at the outlet of step S-a) and step S-c). When the dissolution pressure in step S-a) is greater than or equal to the critical pressure of the dissolving solvent, the dissolution temperature is lower than the critical temperature of the dissolving solvent, so that the dissolving solvent remains at least partially in liquid form. Very advantageously, the dissolution temperature and pressure conditions reached in step S-a) are adjusted so that the mixture (dissolving solvent + target polymer) is a single-phase mixture. Preferably, the ratio by weight of the pretreated plastic feedstock to the dissolving solvent is between 0.01 and 5.0, more preferably between 0.05 and 3.0, even more preferably between 0.10 and 1.0.

[0233] Advantageously, the dissolution step S-a) is carried out for a residence time of between 1 minute and 600 minutes, preferably between 2 minutes and 300 minutes, more preferably between 2 minutes and 180 minutes. The residence time is understood to be the residence time at the dissolution temperature and dissolution pressure, i.e. the implementation time of the pretreated plastic feedstock with the dissolving solvent at the dissolution temperature and dissolution pressure in step S-a). Advantageously, the dissolving solvent used in step S-a) consists of and preferably consists of a fresh supply of solvent and / or a recovered solvent stream obtained from the recovery step S-c). Optionally, the process can comprise an intermediate adsorption step S-a') which is carried out during the dissolution step S-a) or directly downstream of the dissolution step S-a) and which comprises the introduction of an adsorbent solid, preferably for example alumina, silica, silica-alumina, activated carbon or decolorizing earth (for example bleaching earth), in the form of dispersed particles into the crude polymer solution obtained at the end of the dissolution step S-a) or optionally during the dissolution step S-a). The adsorbent solid can then be removed in one of the optional intermediate purification steps, for example during the optional step S-E1) of separation of insoluble substances and / or the optional washing step S-E2). Carrying out the optional adsorption step S-a') in the presence of the adsorbent solid in dispersed form makes it possible to optimize the purification of the polymer solution.

[0234] The crude polymer solution obtained at the end of the dissolution step S-a) comprises at least the solvent for dissolution, the polymer dissolved in the solvent for dissolution, in particular the purified target polymer sought to be recovered according to the application. Generally, the crude polymer solution also comprises soluble impurities which are also dissolved in the solvent for dissolution. It can also optionally contain insoluble impurities or compounds in suspension. The crude polymer solution obtained at the end of step S-a) also optionally comprises polymers other than the target polymer, i.e. other than polypropylene, for example in the form of a melt.

[0235] Optional step S-E1 ) of separation of insoluble matter

[0236] This process can also optionally comprise a step S-E1 ) of separation of insoluble matter by solid-liquid separation, so as to advantageously obtain at least one clarified polymer solution and one insoluble fraction. The insoluble fraction advantageously comprises at least a part, preferably all, of the insoluble impurities, in particular the insoluble impurities obtained in suspension in the crude polymer solution from step S-a).

[0237] When it is incorporated into the process according to the application, the step S-E1 ) of separation of insoluble matter is carried out between the dissolution step S-a) and the polymer recovery step S-c), and upstream or downstream of the adsorption step S-b), preferably upstream of the adsorption step S-b). When the optional step S-E1 ) of separation of insoluble matter is carried out downstream of the adsorption step S-b), the adsorption step S-b) corresponds to an intermediate adsorption step S-a').

[0238] Thus, the step S-E1 ) of separation of insoluble matter makes it possible to remove at least a part, preferably all, of the insoluble compound particles which can be in suspension in the crude polymer solution obtained from step S-a) or from the optional step S-a'), at the temperature and pressure conditions of step S-a). The insoluble impurities removed during the optional step S-E1 ) of separation of insoluble matter are, for example, pigments, mineral compounds, packaging residues (glass, wood, cardboard, paper, aluminium) and insoluble polymers.

[0239] When it is carried out, this separation step S-E1 ) advantageously limits the operating problems of the downstream process steps, in particular clogging and / or corrosion for example, while contributing to the purification of the plastic feedstock.

[0240] When incorporated into the process, the step S-E1 ) of separating insoluble material is advantageously carried out at a temperature comprised between 100°C and 300°C, preferably between 150°C and 250°C, and at a pressure comprised between 1.0 MPa abs and 20.0 MPa abs, preferably between 1.5 MPa abs and 15.0 MPa abs, and even more preferably between 2.0 MPa abs and 10.0 MPa abs. Very advantageously, the optional step S-E1 ) of separating insoluble material is carried out at the temperature and pressure conditions of the dissolution, i.e. at the temperature and pressure conditions at the outlet of the step S-a).

[0241] When incorporated into the process, the crude polymer solution obtained from the step S-a) or from the optional intermediate adsorption step S-a') is preferably fed to the step S-E1 ) of separating insoluble material. According to another embodiment, the washed polymer solution obtained from the optional washing step S-E2) can be fed to the optional step S-E1 ).

[0242] When incorporated into the process, the step S-E1 ) advantageously comprises a section comprising at least one solid-liquid separation device, such as a decanter, a decanting centrifuge, a centrifuge, a filter, a sand filter, an electrofugal separator, an electrostatic separator, a triboelectric separator, preferably a decanter, a filter, a sand filter and / or an electrostatic separator. The removal of insoluble components can be facilitated by devices for transporting and / or removing traces of solvent that can be present in the insoluble components, such as conveyors, vibrating tubes, worms, extruders or stripping columns. The step S-E1 ) can thus comprise devices for transporting and / or removing traces of solvent to remove insoluble components.

[0243] According to a particular embodiment of the optional step S-E1 ), the step S-E1 ) of separating insoluble material comprises at least two and generally less than five solid-liquid separation devices in series and / or in parallel. The presence of at least two solid-liquid separation devices in series makes it possible to improve the removal of insoluble material, while the presence of parallel devices makes it possible to manage the maintenance and / or unblocking operations of the devices.

[0244] Certain insoluble compounds, especially certain pigments and mineral fillers, are generally added during the formulation of the polymer, which can be introduced in the form of particles having a size of less than 1 μιη. This is the case, for example, for titanium dioxide, calcium carbonate and carbon black. According to a particular embodiment of the optional step S-E1), said step S-E1) of separation of insoluble substances advantageously comprises an electrostatic separator, which makes it possible to effectively remove at least part, preferably all, of the insoluble particles having a size of less than 1 μιη. According to another particular embodiment of the optional step S-E1), the step S-E1) of separation of insoluble substances comprises a sand filter, in order to remove particles of different sizes and notably of size less than 1 μιη.

[0245] Depending on the nature of the raw material, the polymer solution fed to the step S-E1), preferably the crude polymer solution, can also optionally comprise a second liquid phase, for example a liquid phase consisting of molten polymer. According to another particular embodiment of the optional step S-E1), the step S-E1) advantageously comprises a device for separation of this second liquid phase, preferably by at least one three-phase separator.

[0246] Adsorption step S-b)

[0247] The treatment process according to the application optionally comprises an adsorption step S-b) in order to obtain at least one refined polymer solution. The refined polymer solution obtained at the end of the step S-b) advantageously comprises the purified target polymer dissolved in the solvent for dissolution sought to be recovered according to the application.

[0248] The adsorption step S-b) is advantageously performed downstream of the dissolution step S-a) and upstream of the polymer recovery step S-c). The adsorption step S-b) is preferably performed upstream or downstream of the additional purification step. For example, it can be performed upstream of the optional steps S-E1) and / or S-E2), and in particular corresponds to the optional intermediate adsorption step S-a'). It can also be performed, for example, upstream or downstream of the optional extraction step S-E3). Thus, the adsorption step S-b) is performed by contacting the polymer solution fed to the step S-b) (in particular the crude polymer solution obtained from the step S-a), the clarified polymer solution obtained from the optional step S-E1), or the washed polymer solution obtained from the optional step S-E2), or the extracted polymer solution obtained from the optional step S-E3) with one or more adsorbents.

[0249] The adsorption step S-b) advantageously comprises an adsorption section operating in the presence of at least one adsorbent, preferably solid, in particular in the form of a fixed bed, of an entrained bed (or slurry, i.e. in the form of particles introduced into the stream to be purified and entrained in this stream) or of a boiling bed, preferably in the form of a fixed bed or of an entrained bed. The adsorbent(s) used in step S-b) are preferably alumina, silica, silica-alumina, activated carbon, decolorizing earth or mixtures thereof, preferably activated carbon, decolorizing earth or mixtures thereof, preferably in the form of a fixed bed or of an entrained bed, the circulation of the stream can be ascending or descending.

[0250] Advantageously, the adsorption step S-b) is carried out at a temperature of 100°C to 300°C, preferably 150°C to 250°C, and at a pressure of 1.0 MPa abs to 20.0 MPa abs, preferably 1.5 MPa abs to 15.0 MPa abs, particularly 2.0 MPa abs to 10.0 MPa abs. Very advantageously, the adsorption step S-b) is carried out under the conditions of the dissolution temperature and the dissolution pressure, i.e. under the dissolution temperature and the dissolution pressure reached in step S-a). Preferably, in step S-b), the hourly space velocity (or HSV) corresponding to the ratio of the volumetric flow rate of the polymer solution fed to step S-b) to the volume of adsorbent is 0.05 h -1 to 10 h -1 , preferably 0.1 h -1 to 5.0 h -1 .

[0251] According to another embodiment, the adsorption section of step S-b) can comprise the addition of adsorbent particles to the polymer solution, in particular to the crude polymer solution, said particles being separable from the polymer solution by a step of removal of the adsorbent particles located downstream of said adsorption section. The removal of the adsorbent particles can advantageously then correspond to the step S-E1) of separation of insoluble substances or to the washing step S-E2). The adsorption step S-b) carried out by the introduction of adsorbent particles followed by a solid / liquid separation advantageously corresponds to the optional intermediate adsorption step S-a') previously described in the present specification.

[0252] Step S-c) of recovery of the polymer

[0253] According to the present application, the process comprises a step S-c) of recovering the polymer to obtain at least one solvent component and one purified polymer component, thereby obtaining a polymer composition comprising a post-consumer polypropylene recycled resin. The polymer recovery step S-c) advantageously involves at least one solvent recovery section, preferably 1 to 6 solvent recovery sections, more preferably 2, 3, 4 or 5 solvent recovery sections. The refined polymer solution or optionally the extracted polymer solution is fed to the polymer recovery step S-c).

[0254] Thus, first the polymer recovery step S-c) at least partially, preferably predominantly, separates one or more solvents, in particular the dissolution solvent, contained in the polymer solution, i.e. the purified polymer solution or the optionally extracted polymer solution, fed to step S-c), in order to recover a polymer which is at least partially, preferably predominantly, and more preferably completely, free of the dissolution solvent and of the other solvent(s) used in the process, which can still be present in the polymer solution fed to step S-c), such as the extraction solvent. The term "predominantly" is to be understood as meaning at least 50% by weight, preferably at least 70% by weight, more preferably at least 90% by weight, and particularly preferably at least 95% by weight, relative to the weight of the one or more solvents contained in the polymer solution fed to step S-c), in particular relative to the weight of the dissolution solvent and optionally the extraction solvent contained in the purified polymer solution and optionally the extracted polymer solution fed to step S-c). Any method known to the person skilled in the art for separating solvents from polymers, in particular any method which enables a phase change of the polymer or of the one or more solvents, can be carried out. The one or more solvents can be separated off, for example, by evaporation and / or flash devolatization, stripping, layering, density differences, and in particular decanting or centrifugation. In a preferred embodiment, the polymer is recovered in at least one solvent recovery section, in particular two, three or four solvent recovery sections, by evaporation and / or flash devolatization at a temperature in the range from 100°C to 300°C, preferably from 1 10°C to 275°C, more preferably from 150°C to 250°C, and at a pressure in the range from 10 Pa abs to 4 MPa abs, preferably from 0.1 kPa abs to 4 MPa abs, in particular from 0.1 kPa abs to 2 MPa abs. In a particular embodiment, the polymer recovery step S-c) involves three or four solvent recovery sections by flash devolatization, wherein the first flash devolatization is carried out at a temperature in the range from 1 10°C to 275°C and at a pressure in the range from 0.8 kPa abs to 2 MPa abs, in particular from 0.1 MPa abs to 2 MPa abs, the last flash devolatization, i.e. the corresponding third or fourth flash devolatization, is carried out at a temperature in the range from 1 10°C to 275°C and at a pressure in the range from 0.1 kPa abs to 1 MPa abs, in particular from 0.1 kPa abs to 0.1 MPa abs, and the intermediate flash devolatization(s) are carried out at a temperature in the range from 1 10°C to 275°C and at a pressure between the first and the last flash devolatization, wherein the pressure is gradually reduced from the first to the last flash devolatization.To protect the recycled polypropylene resin from thermal degradation, a heat stabilizer (e.g. Irganox 1076 and / or Irgafos 168) can be advantageously added to the refined polymer solution resulting from step S-b) before the solvent(s) is / are separated in step S-c).

[0255] The resulting purified polymer component can correspond to a concentrated polymer solution or a solid purified polymer.

[0256] According to a particular embodiment of the application, at least a part of the purified polymer component obtained at the end of step S-c) can be recycled into the dissolving step S-a) to undergo again the treatment cycle, thus increasing the efficiency of the polymer purification.

[0257] After the solvent separation of step S-c), the solvent content is typically less than 5 wt%, preferably less than 2 wt%, more preferably less than 1 wt%, based on the total weight of the purified polymer component.

[0258] Melting treatment step C)

[0259] The following steps are performed on the purified polymer component comprising post-consumer recycled polypropylene resin obtained from step S-c) of the solvent-based recycling process:

[0260] C-a) further separating the solvent from the purified polymer component, preferably by evaporation (herein referred to as degassing) and / or flash devolatilization of the solvent;

[0261] C-b) subjecting the purified polymer component, preferably further comprising added additives, to a melting treatment, preferably to a melt extrusion and / or to a pelletization, to form a melt-treated, preferably melt-extruded and / or pelletized, recycled polypropylene product;

[0262] C-c) optionally aerating the recycled polypropylene product to remove volatile organic compounds, to thereby produce an aerated and melt-treated, preferably melt-extruded and / or pelletized, recycled polypropylene product,

[0263] to obtain the polymer composition of the application comprising post-consumer recycled polypropylene resin, i.e. the melt-treated polymer composition.

[0264] Step C-a) of further separating the solvent from the purified polymer component

[0265] According to the present application, the process comprises further separating the solvent from the purified polymer component, which is preferably done by evaporation and / or devolatilization of the solvent as known to the person skilled in the art. After solvent separation, the solvent content is typically less than 2,000 ppm, preferably less than 1,000 ppm, more preferably less than 500 ppm, based on the total weight of the purified polymer component.

[0266] This step of further separating the solvent (devolatilization) from the purified polymer component helps to remove high-boiling residual contaminants, such as limonene, n-hexanal, toluene and other odor-active substances.

[0267] Step C-a) of further separating the solvent from the purified polymer component can be performed simultaneously with step C-b) of melt processing the purified polymer component. Thus, the solvent can be further separated from the purified polymer component while the purified polymer component is melt processed.

[0268] In a preferred embodiment, the solvent is further separated from the purified polymer component during melt processing the purified polymer component in an extruder having a devolatilization port (as further described below), wherein the extrusion is preferably performed at a temperature in the range of 220 °C to 280 °C, preferably 240 °C to 270 °C, and at a pressure at the devolatilization port of 0.5 kPa abs to 0.1 MPa abs, preferably 1 kPa abs to 50 kPa abs, more preferably 1 kPa abs to 10 kPa abs.

[0269] Generally, the solvent content of the melt-extruded and purified polymer component after the devolatilization can be in the range of 100 ppm to 500 ppm, such as in the range of 300 ppm to 500 ppm, based on the total weight of the purified polymer component.

[0270] Step C-b) of melt processing the purified polymer component

[0271] According to the present application, the process comprises melt processing, preferably melt extruding and / or pelletizing, the purified polymer component, preferably comprising added additives, to form a melt-processed, preferably melt-extruded and / or pelletized, recycled polypropylene product as the melt-processed polymer composition of the present application comprising the post-consumer recycled polypropylene resin of the present application. Optional additives can be added in the molten state or in the solid state to be molten in the polymer melt, preferably in the molten state.

[0272] Step C-b) is preferably carried out in a single-screw or twin-screw extruder, preferably in combination with a suitable pelletizing system. The extruder can be designed for degassing (as described above) and optionally mixing with additives such as polymer stabilizers. The screw speed of the extruder can be in the range of 50 rpm to 500 rpm. The dimensionless throughput Q of the extruder can be in the range of 0.02 to 0.15, preferably 0.03 to 0.12, more preferably 0.03 to 0.10. The target melt temperature of the purified polymer component is typically in the range of 190 °C to 280 °C, preferably 220 °C to 280 °C, more preferably 240 °C to 270 °C.

[0273] In embodiments where the purified polymer component is melt-extruded, the extruder can comprise up to four (e.g. two or three) degassing ports for top and / or side degassing. The absolute pressure at the degassing ports can be in the range of 0.5 kPa abs to 0.1 MPa abs, preferably 1 kPa abs to 50 kPa abs, more preferably 1 kPa abs to 10 kPa abs, which can be achieved by a suitable vacuum system with one or more vacuum pumps, for example.

[0274] Degassing can be improved by adding 0.01 wt% to 1 wt% of a stripping agent, such as an alcohol (e.g. ethanol or isopropanol), supercritical carbon dioxide, water, or any combination thereof, based on the weight of the purified polymer component. The stripping agent is preferably water. One or more stripping agents can be injected into the extruder under pressure with a suitable pump. In embodiments where the extruder comprises three degassing ports, 0.01 wt% to 1 wt% of a stripping agent, such as water, is preferably added in the second and third degassing ports, respectively, based on the weight of the purified polymer component.

[0275] Pelletizing of the melt-processed polymer composition can be carried out using a suitable pelletizing system as known to those skilled in the art, such as selected from underwater pelletizing, strand pelletizing, or watering pelletizing systems. Optionally, a gear melt pump can be used to overcome the pressure drop of the pelletizer die plate to prevent excessive energy input when the extruder is pressurized, which in turn increases the risk of melt temperature and polymer degradation. This can be particularly advantageous for high output lines with large die plates that generate a significant pressure drop (e.g. > 30 bar). The gear melt pump can also prevent one or more extruder screws from reversing and the degassing ports from being flooded, which can result in ineffective degassing and, in the worst case, a production line stop.

[0276] Step C-c) aerating the recycled polypropylene product

[0277] According to the present application, the process can comprise aerating the recycled polypropylene product to remove any residual volatile organic compounds, thereby producing an aerated and melt treated, preferably melt extruded and / or pelletized, recycled polypropylene product as the polymer composition of the present application comprising the post-consumer recycled polypropylene resin of the present application. The aeration can be performed by heating the recycled polypropylene product to a temperature above 100 °C, for example in the range of 110 °C to 130 °C.

[0278] After the aeration, the solvent weight content is typically less than 300 ppm, preferably less than 200 ppm, more preferably less than 100 ppm. Typically, the solvent weight content after the aeration can be in the range of 20 ppm to 100 ppm, based on the total weight of the recycled polypropylene product.

[0279] According to the present application, the polymer composition comprising at least 95 wt% of the post-consumer recycled polypropylene resin based on the total weight of the polymer composition, can be prepared by a process comprising the steps of:

[0280] M) pre-treating the plastic feedstock by a mechanical recycling process comprising sieving; sorting by at least one of polymer type, polymer article form and / or color; shredding; and optionally cleaning, for example washing, of the plastic feedstock to obtain a pre-treated plastic feedstock, and optionally melting the pre-treated plastic feedstock;

[0281] S) solvent-based recycling of the optionally melted and pre-treated plastic feedstock to obtain the post-consumer recycled polypropylene resin by dissolving the plastic feedstock comprising polypropylene in a solvent and separating the undissolved components and soluble impurities, wherein step S) comprises:

[0282] S-a) a dissolving step, wherein the pre-treated plastic feedstock is contacted with a dissolving solvent at a dissolving temperature in the range of 100 °C to 300 °C and a dissolving pressure in the range of 1.0 MPa abs to 20.0 MPa abs to obtain at least one crude polymer solution, preferably one crude polymer solution, wherein the dissolving solvent is selected from organic solvents comprising one or more hydrocarbons having a boiling point in the range of 75 °C to 250 °C to obtain at least one crude polymer solution;

[0283] S-b) an optional adsorbing step by contacting the crude polymer solution obtained from step S-a) with at least one adsorbent at a temperature in the range of 100 °C to 300 °C and a pressure in the range of 1.0 MPa abs to 20.0 MPa abs to obtain at least one refined polymer solution; and

[0284] S-c) recovering the polymer in at least one solvent recovery section, in particular two or three solvent recovery sections, by evaporation and / or flash devolatilization at a temperature in the range of 100 °C to 300 °C, preferably 110 °C to 275 °C, and a pressure in the range of 10 Pa abs to 4 MPa abs, preferably 0.1 kPa abs to 4 MPa abs, in particular 0.1 kPa abs to 2 MPa abs, to obtain at least one solvent component and a purified polymer component; and

[0285] C) subjecting the post-consumer recycled polypropylene resin obtained from step S) to a melt treatment, wherein step C) comprises:

[0286] C-a) further separating solvent from the purified polymer component; and

[0287] C-b) subjecting the purified polymer component to a melt treatment,

[0288] wherein the melt treatment of the purified polymer component is performed in an extruder having a degassing port, wherein the melt treatment is performed at a temperature in the range of 220 °C to 280 °C, preferably 240 °C to 270 °C, and a pressure at the degassing port in the range of 0.5 kPa abs to 0.1 MPa abs, preferably 1 kPa abs to 50 kPa abs, more preferably 1 kPa abs to 10 kPa abs, to obtain the polymer composition.

[0289] Use and article

[0290] The present application also relates to the use of the polymer composition (preferably the melt treated polymer composition) comprising the post-consumer recycled polypropylene resin according to any one of the above embodiments for the manufacture of an article.

[0291] The present application also relates to the use of the polymer composition (preferably the melt treated polymer composition) comprising the post-consumer recycled polypropylene resin according to any one of the above embodiments for packaging applications. The present application also relates to an article comprising the polymer composition (preferably the melt treated polymer composition) comprising the post-consumer recycled polypropylene resin according to any one of the above embodiments.

[0292] The article is preferably selected from caps, closures, bottles, containers, automotive articles, and the like.

[0293] The article preferably comprises more than 20 wt%, preferably more than 30 wt%, most preferably more than 40 wt% of the polymer composition, and preferably also comprises the post-consumer recycled polypropylene resin, based on the total weight of the article.

[0294] For the preparation of the article, (additional) additives can be added to the polymer composition. Especially, common additives for the polypropylene preparation process can be added, such as, for example, modifiers, stabilizers, antistatic agents, lubricants, nucleating agents, blowing nucleating agents, acid scavengers, UV stabilizers, slip agents and pigments, as well as fillers and reinforcing agents. The post-consumer recycled polypropylene resin or the polymer composition according to the present application, preferably the melt-processed polymer composition, is preferably free of any additives or contains only a small amount of additives. Such additives are typically present in the recycled polypropylene from the preparation process of virgin polymers and first-use articles. It is an advantage that the additives can be selectively added based on the intended use of the post-consumer recycled polypropylene resin or the polymer composition, preferably the melt-processed polymer composition.

[0295] Examples

[0296] Measurement methods

[0297] The following definitions of terms and determination methods apply to the above general description of the application as well as to the below examples unless otherwise defined. The measurements in the experimental section are performed on the melt-processed recycled resin, i.e. on the polymer composition, unless otherwise stated.

[0298] Melt flow rate

[0299] The melt flow rate (MFR) is determined according to ISO 1133 and is expressed in g / 10 min. The MFR is an indication of the flowability and processability of a polymer. The higher the melt flow rate, the lower the viscosity of the polymer. In this context, the MFR2 is determined at a temperature of 230 °C and a load of 2.16 kg.

[0300] By 13 C-NMR to determine the ethylene content and the triad distribution of propylene

[0301] Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the ethylene content of the polymers.

[0302] A Bruker Avance Neo 400 NMR spectrometer is used to quantify the ethylene content of the polymers. 1 H and 13 C, respectively, at 400.15 MHz and 100.62 MHz, respectively, quantitative 13 C{ 1 H} NMR spectra are recorded in solution state. All spectra are recorded using a 13A 10 mm extended temperature probe optimized for C was used at 125 °C, all pneumatics used nitrogen. Approximately 200 mg of material was dissolved in approximately 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) 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 form a 60 mM relaxant solution as described in G. Singh, A. Kothari, V. Gupta, Polymer Testing 2009, 28(5), 475.

[0303] To ensure solution homogeneity, after initial sample preparation in the heating zone, the NMR tube was further heated in a rotating oven for at least one hour. After insertion of the magnet, the NMR tube was spun at 10 Hz. This setting was chosen mainly to achieve the high resolution and quantification needed for accurate ethylene content quantification. Standard single pulse excitation without NOE was used, using an optimized tip angle, 1 second recycle delay and a double-step 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.

[0304] Quantification 13 C{ 1 H} NMR spectra were processed, integrated and the relevant quantitative properties were determined from the integrals. All chemical shifts were referenced indirectly to the center methylene of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This method allows comparison to the reference even if this structural unit is not present.

[0305] Characteristic signals corresponding to ethylene incorporation were observed (as described in Cheng, H. N., Macromolecules 1984, 17, 1950) and the comonomer fraction was calculated as the fraction of ethylene in the polymer relative to all monomers in the polymer:

[0306] fE= (E / (P+E))

[0307] The method of W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157 was used to determine the fraction of ethylene in the polymer by integration of the signals13 C{ 1 H} multiple signals within the entire spectral region of the spectrum are integrated to quantify the comonomer fraction. The integration region is fine-tuned to increase applicability over the entire range of comonomer contents that are met.

[0308] The mole percent of comonomer incorporation is calculated from the mole fraction:

[0309] E [mol%] = 100 * fE

[0310] The weight percent of comonomer incorporation is calculated from the mole fraction:

[0311] E [wt%] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1 - fE) * 42.08))

[0312] The amount of comonomer incorporation is calculated from the mole fraction using the method of Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150 by integrating the entire spectral region of the spectrum obtained under the specified conditions. 13 C{ 1 H} multiple signals within the entire spectral region of the spectrum are integrated to quantify the comonomer fraction. The integration region is fine-tuned to increase applicability over the entire range of comonomer contents that are met.

[0313] Crystex analysis, crystalline fraction (CF) and soluble fraction (SF)

[0314] The crystalline fraction (CF) and soluble fraction (SF) of the PCR polypropylene resins and the ethylene content and intrinsic viscosity of the respective fractions were analyzed according to ISO 16152-2022 - Method 2 using a CRYSTEX instrument from Polymer Char (Valencia, Spain). For detailed information on the technique and method see the literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer & Markus Gahleitner (2020) Rapid characterization of high-impact ethylene-propylene copolymer composition by crystallization extraction separation: comparability to standard separation methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596).

[0315] The crystalline fraction and amorphous fraction were isolated by a temperature cycle of dissolution at 160 °C, crystallization at 40 °C and redissolution in 1,2,4-trichlorobenzene at 160 °C. The quantification of SF and CF and the determination of the ethylene content (C2) were achieved by integrating the infrared detector (IR4) and the intrinsic viscosity (IV) was determined using an online dual capillary viscometer.

[0316] The IR4 detector is a multi-wavelength detector for measuring the IR absorbance of two different wavebands (CH3stretching vibration centered around 2960 cm -1 and CH stretching vibration (2700 to 3000 cm -1 ) for the determination of concentration and ethylene content in ethylene-propylene copolymers. The IR4 detector was calibrated with a series of 8 EP copolymers with known ethylene content in the range of 2 to 69 wt% (determined by 13 C-NMR) and a concentration of each copolymer in the range of 2 to 13 mg / ml. In order to simultaneously fulfill the characteristics of the various polymer concentrations and ethylene content expected during the Crystex analysis, the following calibration formula was employed:

[0317] Concentration = a + b*Abs(CH) + c*(Abs(CH)) 2 + d*Abs(CH3) + e*(Abs(CH3)) 2 +

[0318] f*Abs(CH)*Abs(CH3) (Equation 1)

[0319] CH3 / 1000C = a + b*Abs(CH) + c*Abs(CH3) + d*(Abs(CH3) / Abs(CH)) + e*(Abs(CH3) / Abs(CH)) 2 (Equation 2)

[0320] The constants a to e of Equation 1 and a to f of Equation 2 are determined by regression analysis using the method of least squares.

[0321] The CH3 / 1000C is converted into ethylene content in wt% using the following relationship:

[0322] wt%(ethylene in EP copolymer) = 100 - CH3 / 1000TC*0.3

[0323] The Intrinsic Viscosity (IV) of the PCR polypropylene resin and its soluble and crystalline fractions is determined using an online dual capillary viscometer and correlated to the corresponding IV determined by standard method according to ISO 1628-3 in decalin. Various EP, PP copolymers with IV = 2 to 4 dL / g are used for calibration. The determined calibration curve is linear:

[0324] IV (dL / g) = a*Vsp / c

[0325] The sample to be analyzed is weighed in the concentration of 10 to 20 mg / ml. To avoid injection of gels and / or polymers like PET and PA which can be not soluble in TCB at 160°C, the weighed sample is loaded in a stainless steel mesh MW 0.077 / D 0.05 mm.

[0326] After automatic filling of 1,2,4-TCB containing 250 mg / l of 2,6-tert-butyl-4- methylphenol (BHT) as antioxidant into a vial, the sample is dissolved at 160°C until complete dissolution, usually 60 min, with continuous stirring at a speed of 400 rpm. To avoid sample degradation, the polymer solution during dissolution is covered by a nitrogen atmosphere.

[0327] A specified volume of sample solution is injected into a column packed with inert support, crystallization of the sample and separation of the soluble fraction from the crystalline fraction in the column takes place. This process is repeated twice. During the first injection, the whole sample is measured at high temperature, the IV [dl / g] and C2 [wt%] of the PP composition are determined. During the second injection, the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) in the crystallization cycle are measured (wt% SF, wt% CF, wt% C2, wt% C2(SF), wt% C2(CF), IV(SF), IV(CF)), wherein the wt% CF is calculated in the following way:

[0328] wt% CF = 100 - wt% SF

[0329] Cross Fractional Chromatography (CFC)

[0330] The chemical composition distribution and the molecular weight distribution and the corresponding average molecular weights (Mn, Mw and Mv) at specific elution temperatures (polymer crystallinity in solution) are determined by means of a fully automated Cross Fractional Chromatography (CFC) as described in Ortin A., Monrabal B., Sancho-Tello J., Macromol. Symp., 2007, 257, 13-28.

[0331] Cross Fractional Chromatography (TREF x SEC) is performed using a CFC instrument (PolymerChar, Valencia, Spain). The concentration is monitored using a four wavelength IR5 infrared detector (PolymerChar, Valencia, Spain). The polymer is dissolved at 160 °C for 150 minutes at a concentration of approximately 1 mg / ml.

[0332] To avoid the injection of gels and polymers, like PET and PA, which can not be soluble in TCB at 160 °C, the weighed sample is packed into a stainless steel mesh MW 0.077 / D 0.05 mm.

[0333] Once the sample is completely dissolved, an aliquot of 0.5 ml is packed into the TREF column and stabilized at 110 °C for a certain period of time. By applying a constant cooling rate of 0.1 °C / min, the polymer crystallizes and precipitates to a temperature of 30 °C. The following temperature steps are used for the discontinuous elution process: (35 °C, 40 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 103 °C, 106 °C, 109 °C, 112 °C, 115 °C, 117 °C, 119 °C, 121 °C, 123 °C, 125 °C, 127 °C, 130 °C, 135 °C and 140 °C).

[0334] In the second dimension, GPC analysis used a 3PL Olexis column and a 1 x Olexis Guard column from Agilent (Church Stretton, UK) as stationary phase. 1,2,4-Trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-Di tert butyl-4-methylphenol) was applied as eluent at 150 °C at a constant flow rate of 1 mL / min. This column set was calibrated using Universal Calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11500 kg / mol. The PS molecular weight was converted to PP molecular weight equivalents using the following Mark Houwink constants.

[0335] K PS = 19 x 10 -3 mL / g, a PS = 0.655

[0336] K PP = 19 x 10 -3 mL / g, a PP = 0.725

[0337] A third order polynomial fit was used to fit the calibration data. Data processing was done using the software provided by PolymerChar and the CFC instrument.

[0338] a) Calculation of the relative fraction of iso-PP in wt% at a specific molecular weight and elution temperature region

[0339] To calculate the relative fraction of iso-PP in wt% at a specific molecular weight and elution temperature region, the first step requires the calculation of the amount of iso-PP in wt% in the CFC contour plot:

[0340] iso-PP in wt% = 100 - EPR fraction - PE fraction Equation (1)

[0341] where EPR is the fraction at 35 °C in TCB of logM higher than 3.5 of the soluble fraction (SF) of the molar mass obtained by CFC analysis.

[0342] EPR fraction in wt% = 100 - (H

[0343] where H j represents the signal height and j represents the logM value.

[0344] Since the TREF curve has a slight dependency on the low Mw part, the molecular weight limit for the low Mw limit depends on the elution temperature (T el). The low Mw limit is determined using the following equation:

[0345] Low Mw limit (for PE fraction) = 0.0185*T el + 3.1538

[0346] With this in mind, the PE fraction is calculated using the following method.

[0347]

[0348] where H ij is the two-dimensional differential distribution at the respective elution temperature (T el ) and log M value j obtained by the respective data processing software.

[0349] The high crystalline PE component (HCF-PE) is defined as the fraction of the PE component eluting between 90°C and 100°C.

[0350]

[0351] where H ij represents the signal height, i the elution temperature and j the log M value.

[0352] This component mainly contains homopolymer PE and PE copolymers with very low comonomer content, below about 3 SCB / 1000 TC (L. Wild, T. R. Ryle, D. C. Knoblauch, I. R. Peat, J. Polym. Sci, Polym. Phys. 20, (1982), 441-455).

[0353] where the low crystalline PE component (LCF-PE) is defined as the fraction of the PE component eluting between 35°C and 89°C.

[0354]

[0355] where H ij represents the signal height, i the elution temperature and j the log M value.

[0356] This component mainly contains copolymer components from HDPE and LLDPE obtained from ZN catalysts or LLDPE obtained from SS catalysts, as well as LDPE, since the amount of SCB / 1000 TC of these polymers is comparable and thus co-elution occurs.

[0357] b) calculating Mw(PE)(50 to 95°C) and Mw(SF)

[0358] Mw(PE)(50 to 95°C) is calculated using the following equation:

[0359]

[0360] where w i is the weight fraction of the TREF fraction at temperature i, Mw i is the corresponding weight average molecular weight of the fraction as determined by CFC analysis.

[0361] Fractions less than 0.5 wt% were neglected in the calculation.

[0362] where Mw(SF) is the measured Mw value of the 35 °C TREF fraction as determined by CFC analysis.

[0363] c) Calibration of the IR5 detector to determine the number of short chain branches per 1000 total carbon (SCB / 1000TC) content

[0364] The IR5 detector provides different detector signals which are designated as concentration signal (wide spectral band covering the spectral region from 2800 cm -1 to 3000 cm -1 , methyl (CH3) (narrow band filter centered at 2959 cm -1 ) and methylene (CH2) (centered at 2928 cm -1 ) signals. The ratio of the methyl to methylene detector signals is related to the total amount of methyl groups (CH3 / 1000TC) per 1000 carbon atoms (A. Ortin, B. Monrabal, J. Montesinos, P. del Hierro, Macromol. Symp. 2009, 282, 65-70). The determination of CH3 / 1000TC using the IR5 detector can be performed by a calibration of the CH3 / CH2 ratio versus the nominal CH3 / 1000TC content. For this a linear fit is used.

[0365] The degree of branching of all calibration set samples was determined in 13C Melting state NMR determination as described in K. Klimke, M. Parkinson, C. Piel, W. Kaminsky, H. W. Spiess, M. Wilhelm, Macromol. Chem and Phys., 2006, 207, 382; M. Parkinson, K. Klimke, H. W. Spiess, M. Wilhelm, Macromol. Chem. and Phys., 2007, 208, 2128. This method uses a calibration set of 17 different short chain branched polyethylenes, including unit point catalyzed as well as a selection of Ziegler Natta catalyzed polyethylene-co-butene, polyethylene-co-hexene and polyethylene-co-octene, covering a total branching level up to 80 methyl groups (CH3 / 1000C) per 1000C.

[0366] d) Calculate SCB / 1000TC for TREF fractions between 70°C and 95°C

[0367] The SCB / 1000TC content for TREF fractions (70°C to 95°C) is calculated using the following formula:

[0368]

[0369] where w i is the weight fraction of the TREF fraction at temperature i, SCB / 1000TC i is the respective amount of short chain branching per 1000 total C atoms of the respective TREF fraction as analyzed by CFC analysis combined with composition detector analysis. Since the majority of the comonomer in polypropylene compounds is ethylene, the respective C2 content can be calculated in wt% by:

[0370] C2 content (70°C to 95°C) = (1 - SCB / 1000TC (70°C to 95°C) * 3 / 1000) * 100

[0371] Fractions less than 0.5 wt% are neglected in the calculation.

[0372] Basic literature:

[0373] Zhang, Macromol Symp. 282 (2009), 111-127.

[0374] W. Yau, D. Gillespie, Polymer 42 (2001) 8947-8958.

[0375] Monrabal, in "Encyclopedia of Analytical Chemistry", RAMeyers, Ed., John Wiley & Sons Ltd., 2000.

[0376] Nakano, Y. Goto, J. Appl. Polym. Sci. (1981), 26, 4217.

[0377] W. Yau, Macromol. Symp. 2007, 257, 29-45.

[0378] Faldi,JBPSoares,Polymer 42(2001)3057-3066.

[0379] Ortin, B. Monrabal, J, Sancho-Tello, Macromol. Symp. 257 (2007), 13-28.

[0380] The amounts of "iPP", "PVC", "PA", "PET", and "PS" were determined by transmission infrared spectroscopy, and the components and their contents in the recovered polymer resin were determined by FTIR spectroscopy.

[0381] Sample preparation:

[0382] All calibration samples and samples to be analyzed were prepared on fused plates in a similar manner.

[0383] Approximately 2 to 3 g of the analyte compound was melted at 190 °C. Subsequently, a pressure of 60 to 80 bar was applied for 20 seconds in a hydraulic hot press. Next, the sample was cooled to room temperature for 40 seconds in a cold press under the same pressure to control the morphology of the compound. The thickness of the plates was controlled by a 2.5 cm × 2.5 cm, 100 μm to 200 μm thick metal correction frame plate (depending on the MFR of the sample); two plates were produced simultaneously under the same conditions. The thickness of each plate was measured before any FTIR measurements; all plate thicknesses were between 100 μm and 200 μm.

[0384] To control the board surface and avoid any interference during the measurement process, all boards were pressed between two sheets of double-sided silicone release paper.

[0385] For powder samples or heterogeneous compounds, the pressing process will be repeated three times to press and cut the sample under the same conditions as described above to increase homogeneity.

[0386] Spectrometer:

[0387] A standard transmission FTIR spectrometer, such as a Bruker Vertex 70 FTIR spectrometer, is used with the following settings:

[0388] • Spectral range of 4000 cm -1 to 400 cm -1 ,

[0389] • Aperture of 6 mm,

[0390] • Spectral resolution of 2 cm -1 ,

[0391] • Interferogram zero fill factor of 32,

[0392] • Norton Beer strong apodisation.

[0393] • Norton Beer strong apodisation.

[0394] Spectra are recorded and analysed in Bruker Opus software.

[0395] Calibration samples:

[0396] As FTIR is a secondary method, several calibration standards are mixed to cover the range of target analytes, which typically are:

[0397] • Polyamide (PA) from 0.2 wt% to 2.5 wt%

[0398] • Polystyrene (PS) from 0.1 wt% to 5 wt%

[0399] • Polyethylene terephthalate (PET) from 0.2 wt% to 2.5 wt%

[0400] • Polyvinyl chloride (PVC) from 0.1 wt% to 4 wt%

[0401] For the compounds, the following commercially available materials are used: Borealis HC600TF is used as iPP, Borealis FB3450 is used as HDPE, and for the target polymers, RAMA PET N1S (Indorama Polymer) is used as PET, B36LN (BASF) is used as polyamide 6, Styrolution PS 486N (Ineos) is used as high impact polystyrene (HIPS), and for PVC, Inovyn PVC 263B (in powder form) is used.

[0402] ​All compounds were manufactured in a Haake kneader at temperatures below 265°C and small scale for less than 10 minutes to avoid degradation.

[0403] Additional antioxidants were added, such as Irgafos 168 (3000 ppm), to minimize degradation.

[0404] Correction:

[0405] The FTIR correction principle is the same for all components: the intensity of a specific FTIR band is divided by the thickness of the plate, and compared to the same band on a reference sample with a known composition. 1 H or 13 The component quantity determined by C solution NMR is related.

[0406] The choice of each specific FTIR absorption band is made regardless of the composition of the correction standard and the actual sample, due to its intensity increasing with the increasing quantity of component concentration, and due to its separation from the rest of the peaks.

[0407] This method is described in the publication of Signoret et al. “Alterations of plastic in MIR and the potential impacts on identification towards recycling”, Resources, conservation and Recycling journal, 2020, volume 161, article 104980.

[0408] The wavelength of each correction band is:

[0409] • PA is 3300 cm -1 ,

[0410] • PS is 1601 cm -1 ,

[0411] • PET is 1410 cm -1 ,

[0412] • PVC is 615 cm -1 ,

[0413] • iPP is 1167 cm -1 .

[0414] For each polymer component i, a linear correction is constructed (linearity based on Beer-Lambert law). The typical linear relationship for such a correction is shown below:

[0415]

[0416] wherein

[0417] x i is the amount of the polymer component i (in wt%);

[0418] E i is the absorption intensity (in a.u. absorption units) of a specific waveband related to the polymer component i. These specific wavebands are: PA 3300 cm -1 , PS 1601 cm -1 , PET 1410 cm -1 , PVC 615 cm -1 , and iPP 1167 cm -1 ;

[0419] d is the thickness of the sample plate;

[0420] A i and B i are two correlation coefficients determined for each calibration curve.

[0421] For each calibration standard, the amount of each component was determined by 1 H or 13 C solution state NMR as the primary method (except for PA). The NMR measurements were performed on the exact same FTIR plates used for building the FTIR calibration curves.

[0422] Ash content

[0423] Thermogravimetric analysis (TGA) experiments were performed according to ISO 11358-1 (2014) using a Perkin Elmer TGA 8000. Therefore, about 10 to 20 mg of material was placed in a platinum pan. The temperature was equilibrated at 50 °C for 10 minutes, then ramped to 950 °C at a heating rate of 20 °C / min under nitrogen. The ash content was calculated in wt% at 850 °C based on the total weight of the raw material used. As a reference, the ash content was also measured by oven method according to ISO 3451-1 (1997), where comparable results were obtained.

[0424] Metal and chlorine content

[0425] The content of metals and chlorine was determined by X-ray fluorescence (XRF) spectroscopy. The instrument used for the XRF measurements was a wavelength dispersive device produced by Malvern Panalytical called Zetium (2.4 kW). This instrument was calibrated with polyolefins based on a set of standards from Malvern Panalytical. This method was used to determine the quantitative content of F, Na, Mg, Al, Si, P, S, Ca, Ti, Zn, Cr, Cd, Hg, Pb, As, Ni, Cu, Ba, Br, Cl, Sb, Sn in a polyolefin matrix within the specified ranges of these standards. The analysis was performed on a plate of 40 mm in diameter and 2 mm in thickness under vacuum.

[0426] CIEL*a*b* color space values and color difference analysis

[0427] Color values and color differences were determined according to ISO 11664-4.

[0428] In the CIE L*a*b* uniform color space, the color coordinates are: L* - lightness coordinate; a* - red / green coordinate, where +a* indicates red and -a* indicates green; b* - yellow / blue coordinate, where +b* indicates yellow and -b* indicates blue. The L*, a* and b* coordinate axes define a three-dimensional CIE color space. Measurements were made using a standard Konica / Minolta colorimeter CM-3700A.

[0429] About 20 g of cryogenically ground PP powder was placed in a sampling cuvette, avoiding any voids before measurement.

[0430] The color of the IE and CE samples was measured as well as the color of the reference background (here, the L ref = 96.01, a ref = -0.29, b ref = 1.79) and the values of each measurement were saved. The color difference (Euclidean distance DE) between the sample and the reference background was calculated using the resulting colorimetric values and the following equation:

[0431] DE = (DL 2 + Da 2 + Db 2 ) 0.5 = [(L*-L ref ) 2 +(a*-a ref ) 2 +(b*-b ref ) 2 ] 0.5 .

[0432] Headspace gas chromatography / mass spectrometry (HS-GC-MS)

[0433] The determination of the selected marker substances is based on the static headspace (HS) method. This analysis combines the use of a HS sampler, a gas chromatograph (GC) and a mass spectrometer (MS) for screening.

[0434] The samples are transported to the laboratory in sealed, aluminium-coated polyethylene (PE) bags. Before analysis, the samples are ground at low temperature, 2.000 g ± 0.100 g of sample is weighed into a 20 ml HS vial and closed tightly. For each sample, a duplicate determination is performed.

[0435] HS / GC / MS parameters

[0436] HS parameters (Agilent G1888 headspace sampler)

[0437] Vial equilibration time: 120 min (sample), 5 min (standard)

[0438] Oven temperature: 100 °C (sample), 200 °C (standard)

[0439] Loop temperature: 110 °C (sample), 205 °C (standard)

[0440] Transfer line temperature: 120 °C (sample), 210 °C (standard)

[0441] Low speed shaking

[0442] GC parameters (Agilent 7890A GC system)

[0443] Column: ZB-WAX 7HG-G007-22 (30 m x 250 pm x 1 pm)

[0444] Carrier gas: Helium 5.0

[0445] Flow: 2 ml / min

[0446] Split ratio: 10:1

[0447] GC oven program: 35 °C, 0.1 min

[0448] 10 °C / min until 250 °C

[0449] 250 °C, 1 min

[0450] MS parameters (Agilent 5975C inert XL MSD)

[0451] Acquisition mode: Scan

[0452] Scan parameters:

[0453] Low quality: 20

[0454] High quality: 200

[0455] Threshold: 10

[0456] Software / Data evaluation

[0457] MSD ChemStation E.02.02.1431

[0458] MassHunter GC / MS Acquisition B.07.05.2479

[0459] AMDIS GC / MS Analysis version 2.71

[0460] NIST / EPA / NIH Mass Spectral Library (2011 version)

[0461] NIST Mass Spectral Search Program Version 2.0g

[0462] AMDIS deconvolution parameters

[0463] Minimum match factor: 80

[0464] Threshold: Low

[0465] Scan direction: High to low

[0466] Data file format: Agilent file

[0467] Instrument type: Quadrupole

[0468] Component width 20

[0469] Subtract adjacent peaks: 2

[0470] Resolution: High

[0471] Sensitivity: Very high

[0472] Shape requirement: Medium

[0473] Solvent tail: 44 m / z

[0474] Column bleed: 207 m / z

[0475] Minimum model peak: 2

[0476] Minimum S / N: 10

[0477] Minimum specific peak: 0.5

[0478] MSD ChemStation Integration Parameters

[0479] Integrator: ChemStation

[0480] Initial Region Exclusion: 0

[0481] Initial Peak Width: 0.005 (for limonene and acetaldehyde)

[0482] 0.200 (for acetic acid)

[0483] Shoulder Detection: Off

[0484] Initial Threshold: 8.0 (for limonene and acetaldehyde)

[0485] 10.5 (for acetic acid)

[0486] In this study, "below the detection limit (<LOD)" describes the situation where no peak is identified, or the matching factor is below 80 (AMDIS), or the signal-to-noise ratio of the peak in the sample run (Pk-pk S / N = corrected signal / Pk-pk noise, MSD ChemStation signal-to-noise ratio report) is below 3. The results only relate to the measured samples, measurement time, and applied parameters.

[0487] Standard Solution

[0488] To actively identify and compare with the (lowest) odour detection threshold (ODT), standards with specified marker substances were prepared (see Table A). For Standard 1, methanol was used as the solvent; for Standard 2, 2-butanol was used as the solvent.

[0489] For HS / GC / MS analysis, 5 μl of each standard was injected into a separate 20 ml HS vial, sealed, and measured.

[0490] Assuming that all standard substances have been completely vaporized, the concentration C of each analyte in HS G was estimated as listed in Table A.

[0491] Table A: Calibration Standards and ODT

[0492] Analyte Standard c G / ng ml -1 ]]> Target ion (m / z) (minimum) ODT / mg m -3 [1]]]> Acetic acid Standard 1 98 60 0.001 Limonene Standard 1 32 68 0.21 Acetaldehyde Standard 2 71 44 0.0027

[0493] Data Evaluation

[0494] The analyte concentration C in HS G was calculated by considering the amount of substance m G and the available HS volume V G for calculation.

[0495]

[0496] By integration of the extracted ion chromatograms (EIC) the peak area of each analyte is obtained. The respective target ions are listed in Table A. The theoretical peak area of the (lowest) ODT is reflected by the following equation:

[0497]

[0498] For the estimation of the odor relevance of the analytes in the HS above the polymer sample the peak area of the analyte (sample) is compared to the theoretical peak area (ODT).

[0499] In addition, an odor activity factor is introduced. This factor is the fraction of the actual peak area of the analyte (sample) to the theoretical peak area at the lowest ODT found in the literature [1]. Values higher than 1 indicate the relevance of the analyte to the odor at the given HS temperature.

[0500]

[0501] The odor test standard VDA 270-B3, i.e. VDA 270 for the determination of the odor characteristics of interior trim materials in motor vehicles and parts which come into contact with air inside the vehicle.

[0502] For this sensory test a trained and selected panel of odor assessors is required. Usually, 3 test persons are used. If the individual results differ by more than 2 points in one test, or in the case of approved tests, at least 5 test persons are required for a double test. The room in which the sensory test is performed is free of any disturbing odors. Furthermore, the assessors must not be biased by each other due to strong odors such as cigarette smoke, perfume, food odors or similar.

[0503] The samples are sealed in aluminum-coated polyethylene bags. Upon arrival at the laboratory, they are stored open at 23 °C (+ / - 2 °C) for one week and protected from direct sunlight and cross-contamination. For each assessor, 20 g (+ / - 2 g) of sample is weighed into a 1 liter jar, which is immediately closed tightly after weighing.

[0504] The jars are heated to 80 °C (+ / - 2 °C) for 2 hours (+ / - 10 minutes). After that, the jars are cooled to 60 °C (+ / - 5 °C) and the sensory panel is allowed to start the odor assessment.

[0505] Each assessor assesses the odor of the respective sample according to the VDA 270 standard after opening the lid of the jar as small as possible.

[0506] The six-point scale consists of the following grades:

[0507] Grade 1 : Not perceptible;

[0508] Level 2: Detectable, but not disruptive;

[0509] Level 3: Clearly perceptible, but not intrusive;

[0510] Level 4: Interference;

[0511] Level 5: Strong interference;

[0512] Level 6: Unacceptable.

[0513] Evaluators remained calm throughout the evaluation process and were not allowed to discuss personal results or form biases with each other during testing. They were also not permitted to adjust their evaluations after testing another sample.

[0514] For statistical reasons (and as accepted by VDA270), assessors are required to use all steps in the assessment. Therefore, the odor rating is based on the average of all individual assessments and rounded to the nearest integer.

[0515] Charpy notched impact strength (NIS)

[0516] Charpy notched impact strength was determined at 23°C according to ISO 179-1 / 1eA. Compression-molded specimens, 4 mm thick, were prepared from granules according to EN ISO 19069-2. The plates were then ground into 80*10*4 mm (Type B) specimens. The radius of the notch tip was 0.25 mm, and the span used during testing was 62 mm. Nine to ten specimens were tested, and the average value was reported.

[0517] Optical properties

[0518] Haze and total transmittance were measured according to ASTM D1003-13 (Method A - Haze Meter).

[0519] Gloss was measured at 20°, 60° and 85° according to ISO 2813.

[0520] The material is molded into a 1mm thick plate and then die-cut into 60mm×60mm×1mm specimens for testing using ISO D1 molds according to EN ISO 19069-2.

[0521] Optomechanical capability (OMA) and process-centric optomechanical capability (pOMA)

[0522] Optomechanical capability is determined by the following formula:

[0523]

[0524] Therefore, the process-centric optomechanical capability pOMA can be determined according to the following formula:

[0525]

[0526] Determination of Dynamic Mechanical Properties - Tensile Stress

[0527] In Dynamic Mechanical Thermal Analysis (DMTA) in tensile mode, the sample is subjected to a fixed load while a sinusoidal tensile strain is applied. At sufficiently low deformations, the material response remains in the linear viscoelastic regime independent of the magnitude of the strain.

[0528] The tensile storage modulus E'(1) and the tensile loss modulus E"(2) are determined from the following equations:

[0529]

[0530] where,

[0531] ΔF A is the amplitude of the dynamic force measured in Newtons;

[0532] S A is the amplitude of the dynamic displacement measured in meters;

[0533] L a is the distance between the grips measured in meters;

[0534] b is the width of the sample measured in meters;

[0535] d is the thickness of the sample measured in meters;

[0536] δ is the measured phase angle measured in degrees.

[0537] The determination of the so-called damping factor is made according to the following equation.

[0538]

[0539] The characteristics of the dynamic mechanical properties were in accordance with ISO standards 6721-1, 6721-4 and 6721-11. The measurements were performed on a "Netzsch DMA 242E Artemis" strain / stress controlled dynamic mechanical analyzer equipped with a tensile sample holder for rectangular sample geometry. The measurements were performed on rectangular specimens cut from compression molded plaques manufactured using the "Collin 400P / M" hot press process with a temperature of 200 °C for the melting performed at a pressure of 5 bar, an annealing time of 300 seconds, followed by a compression using a pressure of 25 bar for 300 seconds and a cooling to room temperature using a cooling rate of 15 K / min at a pressure of 50 bar. The compression molded plaques were prepared with a geometry of 100 mm x 100 mm x 0.1 mm and stored for a minimum resting time of 96 hours after compression molding. The rectangular samples were prepared using a laboratory cutting machine to ensure a geometry of length x width x thickness of 20 mm x 4 mm x 0.1 mm for the sample clamping. The free tensile length was approximately 12 mm, which was measured at room temperature using a vernier with an accuracy of 0.05 mm. The width and thickness were measured using an appropriate length gauge with an accuracy of 0.001 mm. The dynamic mechanical thermal analysis was performed under inert atmosphere using liquid nitrogen for cooling in the temperature range from -80 °C to +150 °C with a heating rate of 2 K / min, a frequency of 1 Hz, a maximum dynamic applied stress of 7.0 MPa in strain-stress controlled mode, a static load of 0.20 MPa and a maximum strain of 0.20 %. The samples were clamped on the screw using a torque of 2.5 cNm. An isothermal segment of 15 minutes was performed at the starting temperature of -80 °C. The E' was read at a temperature of 90 °C, 120 °C using the "Proteus Thermal Analysis - Version 6.1.0" software. Furthermore, the peak temperature (glass transition temperature T g ) and the E" function on tan delta were determined between -80 °C and 160 °C using a heating rate of 2 K / min and a frequency of 1 Hz.

[0540] The T g (glass transition temperature) was determined from the curve of the loss angle (tan delta).

[0541] References

[0542] [1] "Dynamic mechanical analysis: a practical introduction" Kevin P. Menard Dynamic Testing and Instrumentation, 71-76, 2008

[0543] Tensile properties

[0544] Tensile properties, tensile modulus (E), tensile strength at yield (EAY) and tensile strength at yield (TSY) were measured according to ISO 527-1 / -2 after conditioning time of 96 h at 23 °C, the samples were compression molded into 5A tensile specimens of 2 mm thickness under the following conditions according to EN ISO 19069-2:

[0545] Preload: 1 N; Preload speed: 0.5 mm / min; Test speed modulus: 0.5 mm / min; Test speed: 20.0 mm / min; εχ for determination of σs: 100%; Clamping distance: 50 mm; Gauge length: 20 mm; Modulus: secant, starting modulus: 0.05%; ending modulus: 0.25%.

[0546] Flexibility

[0547] The value of flexibility was calculated according to the following equation:

[0548] Flexibility = EAY * 100000 TSY * E

[0549] wherein EAY is the value of the elongation at yield in %, TSY is the tensile strength at yield in MPa, E is the value of the tensile modulus in MPa, and wherein EAY, TSY and E are determined according to ISO 527 at 23 °C.

[0550] Wide angle X-ray scattering (WAXS)

[0551] The crystallinity of the iPP samples was investigated by WAXS measurements in reflection mode using a Bruker Discover D8 diffractometer equipped with a two-dimensional GADDS detector and Cu Ka X-rays filtered by Ni. Three measurements were performed for each sample and the corresponding results were averaged. The amorphous halo obtained from the atactic PP sample (D. Tranchida, L. Resconi L., Influence of 2,1-erythro regiodefects on the crystallization behavior of isotactic polypropylene, Polymer Crystallization 1 (2018) e10022) was properly scaled and subtracted and the crystallinity index was quantified according to the following method (X C ) :

[0552]

[0553] where A tot is the area under the total pattern, A C is the area after subtraction of the amorphous halo.

[0554] Moreover, the relative content of beta modification was calculated from the intensity of the specific reflection after subtraction of the amorphous halo according to Turner-Jones et al. (A.T. Jones, J.M. Aizlewood, D. Beckett, Crystalline forms of isotactic polypropylene, Makromol. Chem.: Macromol. Chem. Phys. 75 (1964) 134-158):

[0555]

[0556] where gamma modification is calculated from the intensity of the specific reflection after subtraction of the amorphous halo using the method developed by Pae (Pae KD, J. Polym. Sci., Part A, gamma-alpha Solid-solid transition of isotactic polypropylene, 6, (1968) 657-663):

[0557]

[0558] Experiment

[0559] Two inventive examples (IE1 and IE2) and several comparative examples (CE) were prepared.

[0560] CE1, CE2, CE3, CE5 and CE8 were manufactured from post-consumer packaging waste. Among them, the raw material of CE1 mainly contains flexible polyolefin products such as films, shopping bags, etc.; while the raw material of CE2, CE3, CE5 and CE8 mainly contains rigid PP products, such as bottles, cups and trays, etc. CE1, CE2, CE3, CE5 and CE8 are obtained from a recycling process comprising the following steps:

[0561] screening the plastic raw material to produce a screened plastic waste material having only objects with a maximum longest dimension of 400 mm;

[0562] sorting products made of polystyrene, polyamide, polyethylene, metal, paper and wood from the raw material, thereby providing post-consumer plastic material; by color sorting of natural colored products (e.g. CE5) and white products (e.g. CE2) and light colored components (e.g. CE1) to obtain CE1, CE2 and CE5 as light colored components, the material not sorted remains as post-consumer mixed color polypropylene recyclate with a specified color mixture (e.g. CE3A and CE3B);

[0563] wet grinding of the selected post-consumer plastic material with a specified color to form a post-consumer plastic material in the form of flakes with a maximum longest dimension of 20 mm and washing in an aqueous solution with the help of thermal energy to reach a temperature in the range of 35 to 95 °C and a residence time in the range of 1 to 20 minutes using various cleaning agents under alkaline conditions by adding NaOH with a concentration of 1.5 to 2 wt.%, followed by drying with a final moisture content below 2 wt.%, air classification and screening to separate specific polymer materials other than the polypropylene to be recycled and by screening out <2.5 mm components to reduce the number of flake materials to an optimal size range for optical sorting; further sorting of the thus obtained pre-processed post-consumer plastic material to remove non-polyolefins and specific colored parts, thereby producing a purified polypropylene polyolefin recyclate stream; melt extrusion of the material and melt filtration applying a melt screen size in the range of 90 to 110 pm to obtain a polypropylene blend in the form of granules as an extruded, pelletized, recycled polypropylene product.

[0564] CE3A and CE3B are prepared from different raw materials.

[0565] The polypropylene content of the extruded, pelletized, recycled polypropylene products CE1, CE2, CE3A, CE3B, CE5 and CE8 was about 95 wt% (see Table 1 below). During extrusion, 1500 ppm of Irganox 1010 and 1500 ppm of Irgafos 168 were added to each of the comparative samples CE1, CE2, CE3A, CE3B, CE5 and CE8.

[0566] These mechanically recycled polypropylene products can be further treated with the solvent-based recycling process described herein.

[0567] CE5B is a "high purity" reference product which was mechanically recycled after drying the polymer pellets prepared from CE5 for 4 h at 120 °C.

[0568] CE4 is a commercially available heterophasic propylene copolymer composition "BE170CF" obtained from Borealis AG, Austria.

[0569] CE6 is a commercially available random propylene copolymer composition "RD204CF" obtained from Borealis AG, Austria.

[0570] CE7 is a commercially available random propylene copolymer composition "RD734MO" obtained from Borealis AG, Austria.

[0571] Inventive Example IE1 was prepared from mechanically recycled CE3A (in the form of a flake material) and Inventive Example IE2 was prepared from mechanically recycled CE3B (in the form of a flake material), which were prepared by the same solvent-based recycling process.

[0572] Inventive Example 1

[0573] A pre-purified feedstock (CE3A) containing 95 wt% polypropylene (PP) was introduced into an extruder heated to 200 °C in the form of a flake. At the outlet of the extruder, the feedstock was at least partially in a molten form (i.e. at least substantially all of the polyolefin material was in a molten form) mixed with n-heptane preheated to 200 °C, the weight ratio of solvent:feedstock being 5:1. The mixture containing the solvent and the feedstock was introduced into a stirred reactor heated to 200 °C and maintained at 2.0 MPa abs, the residence time being 1 hour. A polymer solution having a high homogeneity was thus obtained.

[0574] The polymer solution was continuously discharged from the stirred reactor and introduced into a static settling tank. The settling was performed at 200 °C and 2.0 MPa.

[0575] The clarified polymer solution is continuously discharged from the settling tank and passed through two filters in series, maintained at 200 °C, and having a cut diameter equal to 10 pm and 1 pm, respectively (in this order).

[0576] At the outlet of the series filters, the pre-purified polymer solution is subsequently passed through an adsorption section comprising a bed of carbon particles. This adsorption step is carried out at 200 °C and 2.0 MPa, so that the weight content of carbon particles is 6.3 wt% of the weight of the pre-purified polymer solution.

[0577] The purified solution at the outlet of the adsorption section is then subjected to solvent-polymer separation by evaporation of n-heptane to obtain a post-consumer recycled polypropylene resin, which is further prepared into composition IE1 by extrusion as described below. The solvent-polymer separation is carried out in a flash devolatilization section at an inlet temperature of 180 °C and a pressure of 0.14 MPa.

[0578] Inventive Example 2

[0579] A pre-purified feedstock (CE3B) containing 95 wt% polypropylene (PP) is introduced in the extruder in the form of a pellet, heated to 200 °C. At the outlet of the extruder, the feedstock, at least partially in molten form (i.e. at least substantially all the polyolefin material is in molten form), is mixed with n-heptane preheated at 200 °C, the weight ratio solvent:feedstock being 5:1. The mixture containing the solvent and the feedstock is introduced in a stirred reactor heated to 200 °C and maintained at 2.0 MPa abs, the residence time being 1 hour. A polymer solution is thus obtained.

[0580] The polymer solution is continuously discharged from the stirred reactor and introduced in a static settling tank. The settling is carried out at 200 °C and 2.0 MPa.

[0581] The clarified polymer solution is continuously discharged from the settling tank and passed through two filters in series, maintained at 200 °C, and having a cut diameter equal to 10 pm and 1 pm, respectively (in this order).

[0582] At the outlet of the series filters, the pre-purified polymer solution is subsequently passed through an adsorption section comprising a bed of carbon particles. This adsorption step is carried out at 200 °C and 2.0 MPa, so that the weight content of carbon particles is 3.2 wt% of the weight of the pre-purified polymer solution.

[0583] The purified solution at the outlet of the adsorption section is then subjected to solvent-polymer separation by evaporation of n-heptane to obtain a post-consumer recycled polypropylene resin, which is further prepared into composition IE2 by extrusion as described below. The solvent-polymer separation is carried out in a flash devolatilization section at an inlet temperature of 180 °C and a pressure of 0.14 MPa.

[0584] To simulate the solvent removal efficiency of a devolatilization and / or degassing extruder, IE1 and IE2 were cryogenically ground into a powder and dried overnight at 90 °C using a vacuum of about 10 mbar abs (1 kPa abs) for about 16 hours. Due to the low amount of cryogenically ground powder, a small extruder was used to produce pellets from the cryogenically ground and dried polymer powder. The small extruder was a machine with a screw diameter of 16 mm without a degassing option. The extruder was operated at a rotational speed of 200 rpm and a throughput of 1 kg / h. 1500 ppm of the stabilizers Irganox 1010 and Irgafos 168 were added, respectively. Thus, the pellets of IE1 and IE2 (melt-processed polymer composition) contained at least 99 wt% of post-consumer recycled polypropylene resin and about 0.3 wt% of additives, based on the total weight of the polymer composition. The pellet samples were analyzed without any further stirring or devolatilization step. The properties of the PCR polypropylene samples are shown in Table 1 below.

[0585] Table 1: General properties of comparative and inventive examples.

[0586]

[0587]

[0588] * measured on powder samples before melt processing (i.e. extrusion)

[0589] The following abbreviations are used in all tables herein:

[0590] n.d. = not detected, i.e. below the limit of detection and / or below the limit of quantification;

[0591] n.m. = not measured;

[0592] LOQ = limit of quantification;

[0593] LOD = limit of detection.

[0594] As can be seen from Table 1, the inventive examples (IE1, IE2) have a general level of properties when compared to other recycled polypropylene samples (i.e. CE1 to CE3) and virgin polypropylene (CE4).

[0595] Table 2: Contaminants in comparative and inventive examples.

[0596]

[0597] * measured on powder samples before melt processing (i.e. extrusion)

[0598] As can be seen from Table 2, the contaminant levels in the inventive examples (IE1, IE2) are substantially reduced when compared to the other recycled polypropylene samples (i.e. CE1 to CE3). The levels of certain contaminants are lower than the virgin polypropylene (i.e. CE4).

[0599] Table 3: Emission properties of comparative and inventive examples.

[0600]

[0601]

[0602] *Measured on powder samples before melt processing (i.e. extrusion)

[0603] LOD estimation: using a signal to noise threshold of 3 and multiplying this by the standard concentration and dividing by the signal to noise value of the corresponding standard analysis.

[0604]

[0605] As can be seen from Table 3, the emission levels in the inventive examples (IE1, IE2) are substantially reduced when compared to the other recycled polypropylene samples (CE3A, CE3B, CE5B) whether as a resin powder or as a melt processed form after pelletisation.

[0606] Table 4: Colour properties of comparative and inventive examples.

[0607]

[0608] *Samples produced from a compression moulding plaque

[0609] As can be seen from Table 4, the substantially reduced colouring in the inventive examples (IE1, IE2) is significantly less when compared to the recycled polypropylene sample CE3A and is at a similar level to CE2 and CE5 where, in addition to white and natural colour materials, the remaining materials have been sorted out.

[0610] Table 5: Properties of comparative and inventive examples.

[0611]

[0612] *Measured on powder samples before melt processing (i.e. extrusion)

[0613] As can be seen from Table 5, the inventive examples (IE1, IE2) have properties of a general level when compared to the other recycled polypropylene samples (i.e. CE1 to CE3A) and the virgin polypropylene (CE4).

[0614] Table 6: Optical and mechanical properties of comparative and inventive examples.

[0615]

[0616] From the data of Table 6, it can be seen that the optical properties of the present invention (IE2) have similar values to the virgin polymer of similar composition (CE4) compared to other recycled materials of similar composition (CE3B), and similar to CE5, requiring sorting for all colors except natural color. Surprisingly, IE2 achieves a high total light transmission despite the higher haze.

[0617] Table 7: Comparative and inventive examples further mechanical properties.

[0618]

[0619]

[0620] From the data of Table 7, it can be seen that the bendability parameter shows that the mechanical properties of SbR materials IE1 and IE2 are improved (57% to 62% higher) compared to their mechanically recycled reference materials CE3A and CE3B, respectively. This parameter is similar to the one that can be obtained with the virgin heterophasic PP reference material CE4; this indicates that the material is similar to virgin material in this respect.

[0621] Table 8: Comparative and inventive examples dynamic mechanical properties.

[0622]

[0623] From the data of Table 8, it can be seen that the composition provided by the present invention (IE2) has similar values of E'(120°C) and T(E' = 400 MPa) to the virgin polymer (CE4) compared to other recycled materials (CE3B), indicating similar dimensional stability at elevated temperatures to the virgin polymer (CE4).

[0624] The pellets of IE1, IE2 and CE8 were analyzed by WAXS to determine the crystallinity (X c ) and the content of the beta and gamma phases of the crystal structure (the remaining phase is the alpha phase).

[0625] The melting temperature (T m ) and the crystallization temperature (T c ) of the samples were determined by DSC (10 K / min).

[0626] Table 9: Comparative and inventive examples WAXS data.

[0627]

[0628] As can be seen from Table 9, each of the samples IE1 and IE2 contained significantly less gamma phase (Kg) than the mechanically recycled comparative sample CE8.

[0629] The ash content of sample CE8 was determined to be 0.07 wt% (ISO 3451-1), the MFR was 14 g / 10 min (230°C / 2.16 kg), the C2 content was 4.2 wt% (Crystex), and the C2(CF) content was 3.9 wt% (Crystex).

Claims

1. A polymer composition, preferably a melt-processed polymer composition, comprising at least 95 wt% of a post-consumer recycled polypropylene resin based on the total weight of the polymer composition, the polymer composition having the following features: an ethylene content (C2(CF)) of the crystalline fraction (CF) in the range of [C2-3.4] wt% to [C2-0.2] wt%, preferably [C2-3.0] wt% to [C2-0.6] wt%, more preferably [C2-2.4] wt% to [C2-1.2] wt%, based on the total weight of the crystalline fraction of the polymer composition, determined by Crystex analysis as described in the specification; and a total light transmission in the range of 60% to 100%, preferably in the range of 65% to 90%, more preferably in the range of 70% to 85%, measured according to ASTM D1003-13 on a compression-molded plaque of 60 mm x 60 mm x 1 mm.

2. The polymer composition according to claim 1, wherein, The polymer composition is obtained or obtainable from a plastic feedstock by a recycling process comprising the following steps: M) pre-treating the plastic feedstock by a mechanical recycling process comprising subjecting the plastic feedstock to: screening; sorting by at least one of polymer type, polymer article form, and / or color; crushing; and optionally cleaning, e.g. washing, to obtain a pre-treated plastic feedstock; S) subjecting the pre-treated plastic feedstock to a solvent-based recycling process to obtain a post-consumer recycled polypropylene resin by dissolving the plastic feedstock comprising polypropylene in a solvent and separating the undissolved components and soluble impurities, wherein step S) comprises: S-a) a dissolving step, wherein the pre-treated plastic feedstock is contacted with a dissolving solvent at a dissolving temperature of 100 °C to 300 °C and a dissolving pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one crude polymer solution, preferably one crude polymer solution, wherein the dissolving solvent is selected from organic solvents comprising one or more hydrocarbons having a boiling point between 75 °C and 250 °C to obtain at least one crude polymer solution; S-b) an optional adsorption step by contacting the crude polymer solution obtained from step S-a) with at least one adsorbent at a temperature of 100 °C to 300 °C and a pressure of 1.0 MPa abs to 20.0 MPa abs to obtain at least one refined polymer solution; and S-c) a step of recovering the polymer to obtain at least one solvent component and one purified polymer component; and C) melt-processing the post-consumer recycled polypropylene resin obtained from step S), wherein step C) comprises: C-a) further separating solvent from the purified polymer component; and 3. The polymer composition according to any one of the preceding claims, wherein, C-b) melt-processing the purified polymer component, to obtain the polymer composition. The polymer composition has the following features: tensile The modulus E is in the range of 1200 MPa to 2000 MPa, preferably in the range of 1300 MPa to 1900 MPa, more preferably in the range of 1400 MPa to 1800 MPa, most preferably in the range of 1500 MPa to 1700 MPa, measured according to ISO 527-1 / -2 on a tensile type 5A specimen with a thickness of 2 mm as described in the specification.

4. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: In 23 °C in the range of 2.0 to 7.0 kJ / m 2 2, more preferably in the range of 3.0 to 6.0 kJ / m 2 2, more preferably in the range of 3.0 to 6.0 kJ / m 2 2, more preferably in the range of 3.0 to 6.0 kJ / m 2 2, more preferably in the range of 3.0 to 6.0 kJ / m 2 2, more preferably in the range of 3.0 to 6.0 kJ / m 2 measured according to ISO 179-1 / 1 eA using compression moulded specimens of 80 mm x 10 mm x 4 mm prepared according to EN ISO 19069-2.

5. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The optical mechanical capability or process centered optical mechanical capability is at least 50, determined as defined in the specification.

6. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The tensile strength at yield (TSY) is at least 26 MPa, in particular in the range of 28 MPa to 50 MPa, preferably at least 28 MPa, more preferably at least 30 MPa, measured according to ISO 527-1 / -2 as described in the specification; and / or The bendability is greater than 9, preferably greater than 10, for example in the range of 9 to 15, calculated as defined in the specification.

7. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The heat distortion resistance is at least 97°C, preferably in the range of 97°C to 110°C, more preferably in the range of 98°C to 105°C, determined with DMTA according to ISO 6721-7 and expressed in temperature at which the storage modulus E' of 400 MPa is reached (T(E' = 400 MPa); and / or The storage modulus (E', 90°C) is in the range of 470 MPa to 600 MPa, preferably in the range of 480 MPa to 550 MPa, determined by DMTA at 90°C as described in the specification; and / or The storage modulus (E', 120°C) is in the range of 210 MPa to 350 MPa, preferably in the range of 240 MPa to 300 MPa, determined by DMTA at 120°C as described in the specification.

8. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The ash content (w / w) is at most 0.07 wt% of the total weight of the polymer composition, determined according to thermogravimetric analysis (TGA) as described in the specification; and / or The heavy metal content (w / w) is less than 10 ppm of the total weight of the polymer composition, determined by X-ray fluorescence (XRF) spectroscopy as described in the specification as the sum of the metal content of cadmium, chromium, mercury and lead; and / or The titanium content (w / w) is less than 100 ppm, preferably less than 50 ppm, more preferably less than 20 ppm, based on the total weight of the polymer composition, determined by X-ray fluorescence (XRF) spectroscopy as described in the specification; and / or The content (w / w) of at least one of aluminum, calcium or chlorine is less than 40 ppm of the total weight of the polymer composition, determined by X-ray fluorescence (XRF) spectroscopy as described in the specification.

9. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The ratio of the molecular weight of the soluble component (SF) to the molecular weight of the ethylene polymer (PE): Mw(SF) / Mw(PE) greater than 2, determined by cross-fractional chromatography (CFC) as described in the specification; and / or In temperature-elution fractionation (TREF), the ethylene content of the fraction eluted between 70°C and 95°C is less than 34 wt% C2, as determined by cross-fractional chromatography (CFC) as described in the instructions; and / or The ratio PEP / EEE of the ter-level comonomer sequence distribution is greater than 0.3, preferably greater than 0.4, as determined by quantitative 13 C{ 1 H}NMR spectroscopy; and / or Based on the total weight of the polymer composition, the ethylene propylene rubber content is less than 12 wt%, more preferably less than 10 wt%, and typically at least 0.1 wt%, as determined by cross-gradient chromatography (CFC) as described in the specification.

10. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has the following characteristics: The content of each of the compounds selected from aldehyde, limonene, benzene, styrene, and toluene in the polymer composition is below the detection limit, and is determined by headspace gas chromatography / mass spectrometry (HS-GC-MS) as described in the specification; and / or When determined by headspace gas chromatography / mass spectrometry (HS-GC-MS) as described in the specification, the content of compounds with boiling points below 250°C in the polymer composition is below the detection limit.

11. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The L* value in the CIEL*a*b* color space is at least 75, preferably 86 to 97, more preferably 89 to 97, as determined according to ISO 11664-4; and / or The color difference ΔE compared to the reference background is less than 7.5, which is determined according to ISO 11664-4 using the following equation: ΔΕ = (DL 2 + Da 2 + Db 2 ) 0.5 = [(L*-L ref ) 2 +(a*-a ref ) 2 +(b*-b ref ) 2 ] 0.5 , wherein the value of the reference background is: L ref = 96.01, a ref = -0.29, b ref = 1.79; and / or The CIEL*a*b* color space is: L* is 86 to 97, preferably 89 to 97; a* ranges from -0.5 to 0.0; b* is 0.0 to 10.0, preferably 0.0 to 5.0; It was determined according to ISO 11664-4.

12. The polymer composition according to any one of the preceding claims, wherein, The post-consumption recycled polypropylene resin has at least one of the following characteristics: The L* value in the CIEL*a*b* color space is at least 75, preferably 86 to 97, more preferably 90 to 97, as determined according to ISO 11664-4; and / or The color difference ΔE compared to the reference background is less than 6, which is determined according to ISO 11664-4 using the following equation: ΔΕ = (DL 2 + Da 2 + Db 2 ) 0.5 = [(L*-L ref ) 2 + (a*-a ref ) 2 + (b*-b ref ) 2 ] 0.5 , wherein the value of the reference background is: L ref = 96.01, a ref = -0.29, b ref = 1.79; and / or The CIEL*a*b* color space is: L* is 86 to 97, preferably 89 to 97; a* ranges from -0.5 to 0.0; b* is 0.0 to 10.0, preferably 0.0 to 5.0; It was determined according to ISO 11664-4.

13. The polymer composition according to any one of the preceding claims, wherein, When measured by FTIR spectroscopy, the polymer composition does not include at least one of polyamide and / or polystyrene polymer and / or PET and / or PVC.

14. The polymer composition according to any one of the preceding claims, wherein, The polymer composition has at least one of the following characteristics: The crystalline component (CF) content is 85 wt% to 95 wt% of the total weight of the polymer composition, preferably 87 wt% to 94 wt%, more preferably 88 wt% to 93 wt%, as determined by Crystex analysis as described in the specification; and / or a soluble fraction content (SF) of 5 wt% to 15 wt%, preferably 6 wt% to 13 wt%, more preferably 7 wt% to 12 wt%, based on the total weight of the polymer composition, as determined according to the Crystex analysis as described in the description; and / or a total ethylene content (C2) of 1.5 wt% to 10.0 wt%, preferably 2.0 wt% to 8.0 wt%, more preferably 2.0 wt% to 7.0 wt%, based on the total weight of the polymer composition, as determined according to the Crystex analysis as described in the description.

15. The polymer composition according to any one of the preceding claims, wherein, the polymer composition has at least one of the following characteristics: a melt flow rate MFR2 in the range of 10 g / 10 min to 40 g / 10 min, preferably 12 g / 10 min to 36 g / 10 min, more preferably 15 g / 10 min to 30 g / 10 min, determined according to ISO 1133 at a load of 2.16 kg and 230 °C; and / or an intrinsic viscosity of the soluble fraction (IV(SF)) in the range of 0.8 dl / g to 3.0 dl / g, preferably 0.9 dl / g to 2.5 dl / g, more preferably 1 dl / g to 2 dl / g, as determined according to the Crystex analysis as described in the description.

16. The polymer composition according to any one of the preceding claims, wherein the post-consumer recycled polypropylene resin comprises at least 80 wt%, such as 80 wt% to 99 wt%, preferably at least 90 wt%, more preferably at least 95 wt%, of at least one post-consumer recycled polypropylene, as determined by Fourier Transform Infrared (FTIR) spectroscopy as described in the description, based on the total weight of the post-consumer recycled polypropylene resin.

17. The polymer composition according to any one of the preceding claims, wherein, the polymer composition comprises at least 97 wt%, preferably at least 98 wt%, more preferably at least 99 wt%, of the post-consumer recycled polypropylene resin, based on the total weight of the polymer composition.

18. Use of the polymer composition (preferably a melt-processed polymer composition) according to any one of the preceding claims for the manufacture of an article.

19. An article comprising the polymer composition according to any one of claims 1 to 17.

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