Recyclate-containing fiber-reinforced polypropylene composition

Abstract

A fiber-reinforced polypropylene composition (PC) that comprises: a) from 10.0 to 60.0 wt.-% of one or more propylene-ethylene random copolymers (C3C2); b) from 10.0 to 60.0 wt.-% of one or more recycled polypropylenes (RPP); c) from 20.0 to 50.0 wt.-% of glass fibers (GF); d) optionally, from 0.0 to 5.0 wt.-%, of one or more adhesion promoters (AP); e) optionally, from 0.0 to 10.0 wt.-% of one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters; f) optionally, from 0.0 to 5.0 wt.-% of one or more pigments (P); and g) optionally, from 0.0 to 30.0 wt.-% of one or more further additives (A), wherein the combined content of the one or more propylene-ethylene random copolymers and the recycled polypropylene is in the range from 40.0 to 70.0 wt.-%.

Description

[0001] Recyclate-containing fiber-reinforced polypropylene composition

[0002] Field of the Invention

[0003] The present invention is directed to a fiber-reinforced polypropylene composition that comprises glass fibers, one or more propylene ethylene random copolymers, and a recycled polypropylene, and to injection moulded articles comprising said fiber-reinforced polypropylene composition.

[0004] Background to the Invention

[0005] Long glass fiber-reinforced polypropylene is commonly used to produce structural parts for a range of applications. The glass-fibers embedded in the polymer matrix enhance the mechanical properties of the composition, an effect that can be controlled by adjusting the amount of glass fibers and the length of the glass fibers. Whilst it is well-known that increasing the length and / or amount of glass fibers is beneficial for improving the reinforcing effect, this is accompanied by a considerable deterioration in the surface properties, with the glass fibers causing inhomogeneities that are visible on the surface of the resultant products, such as injection moulded articles. These surface defects are particularly problematic for dark-coloured compositions, since the surface defects are more noticeable to the naked eye due to the contrast relative to the dark background. In many applications, such as automotive applications, the resulting products are (partially) visible during use, thus the surface appearance is important.

[0006] It is thus extremely challenging to balance the mechanical properties with the surface appearance properties. Most commercially available long glass fiber-reinforced polypropylene compositions inevitably have had to compromise to achieve values that are acceptable but not optimal.

[0007] There is thus a long held need to improve the surface appearance of long glass fiber- reinforced polypropylene compositions without resorting to shorter glass fibers and / or lower glass fiber content, thereby achieving a beneficial balance of both the surface appearance and mechanical properties that is superior to that known in the art. Polypropylene based materials offer significant potential for mechanical recycling, as these materials are extensively used in packaging. Taking into account the huge amount of waste collected compared to the amount of waste recycled back into the stream, there is still a great potential for intelligent reuse of plastic waste streams and for mechanical recycling of plastic wastes.

[0008] Development of polyolefins and polyolefin blends is often focused on the continuous goal of improving the balance of mechanical properties, and also the more effective handling of waste streams, for both economical and also environmental reasons. It is usually understood that the use of recycled materials in polymer blends tends to lead to a degradation of mechanical properties, since the mechanical properties of virgin polymers can easily be modified by the polymerization conditions, whereas controlling the properties of a recycled material is intrinsically more difficult, resulting in poorer performance of these compositions.

[0009] Recently, the demand of the market has expanded in direction of using recycled polyolefins in blends with virgin polymers in order to fulfil specific requirements.

[0010] However, there is a deeply felt need for allowing the reuse of post-consumer polyolefin recy elates in final products without health and safety hazards.

[0011] Due to the poor homogeneity of recyclate blends, it is generally understood that properties that would be desirable for automotive articles, for example surface appearance, are notably lower for such recyclate blends than for similar virgin polymer.

[0012] As such, a recyclate-containing long glass fiber-reinforced polypropylene composition that is able to achieve a beneficial balance of both the surface appearance and mechanical properties is a particularly relevant goal.

[0013] Summary of the Invention

[0014] The present invention is based on the finding that the surface appearance of injection moulded parts can be improved by careful polymer design, allowing for the addition of polypropylene-based recyclates and removing the need to shorten the glass fibers and thus avoid compromising on mechanical properties.

[0015] As such, in a first aspect, the present invention is directed to a fiber-reinforced polypropylene composition (PC) that comprises: a) an amount in the range from 10.0 to 60.0 wt.-%, relative to the total weight of the fiber- reinforced polypropylene composition (PC), of one or more propylene-ethylene random copolymers (C3C2); b) an amount in the range from 10.0 to 60.0 wt.-%, relative to the total weight of the fiber- reinforced polypropylene composition (PC), of one or more recycled polypropylenes (RPP); c) an amount in the range from 20.0 to 50.0 wt.-%, relative to the total weight of the fiber- reinforced polypropylene composition (PC), of glass fibers (GF); d) optionally, an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more adhesion promoters (AP); e) optionally, an amount in the range from 0.0 to 10.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters; f) optionally, an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more pigments (P); and g) optionally, an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further additives (A), wherein the combined content of the one or more propylene-ethylene random copolymers (C3C2) and the one or more recycled polypropylenes (RPP) is in the range from 40.0 to 70.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC).

[0016] In a second aspect, the present invention is directed to an injection moulded article comprising at least 90 wt.-%, relative to the total weight of the article, of the fiber-reinforced polypropylene composition (PC) of the first aspect. Definitions

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although, any methods and materials similar or equivalent to those described herein can be used in practice fortesting of the present invention, the preferred materials and methods are described herein. In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below.

[0018] Unless clearly indicated otherwise, use of the terms “a”, “an”, and the like refers to one or more.

[0019] In the following amounts are given in % by weight (wt.-%) unless it is stated otherwise.

[0020] A propylene homopolymer is a polymer that essentially consists of propylene monomer units. Due to impurities especially during commercial polymerization processes, a propylene homopolymer can comprise up to 0.1 mol-% comonomer units, preferably up to 0.05 mol-% comonomer units and most preferably up to 0.01 mol-% comonomer units.

[0021] A propylene random copolymer is a copolymer of propylene monomer units and comonomer units, preferably selected from ethylene and C4-C8 alpha-olefins, in which the comonomer units are distributed randomly over the polymeric chain. The propylene random copolymer can comprise comonomer units from one or more comonomers different in their amounts of carbon atoms.

[0022] Heterophasic propylene copolymers typically comprise: a) a crystalline propylene homopolymer or copolymer matrix (M); and b) an elastomeric rubber, preferably a propylene-ethylene copolymer (E).

[0023] In case of a random heterophasic propylene copolymer, said crystalline matrix phase is a random copolymer of propylene and at least one alpha-olefin comonomer. The elastomeric phase can be a propylene copolymer with a high amount of comonomer that is not randomly distributed in the polymer chain but is distributed in a comonomer-rich block structure and a propylene-rich block structure. A heterophasic polypropylene usually differentiates from a monophasic propylene copolymer in that it shows two distinct glass transition temperatures Tg which are attributed to the matrix phase and the elastomeric phase.

[0024] The present invention will now be described in more detail.

[0025] Detailed Description

[0026] In a first aspect, the present invention is directed to a fiber-reinforced polypropylene composition (PC) that comprises, more preferably consists of: a) an amount in the range from 10.0 to 60.0 wt.-%, more preferably in the range from 18.0 to 50.0 wt.-%, most preferably in the range from 25.0 to 40.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more propylene-ethylene random copolymers (C3C2); b) an amount in the range from 10.0 to 60.0 wt.-%, more preferably in the range from 15.0 to 45.0 wt.-%, most preferably in the range from 20.0 to 35.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more recycled polypropylenes (RPP); c) an amount in the range from 20.0 to 50.0 wt.-%, more preferably in the range from 25.0 to 45.0 wt.-%, most preferably in the range from 28.0 to 42.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of glass fibers (GF); d) optionally, an amount in the range from 0.0 to 5.0 wt.-%, more preferably in the range from 0.0 to 3.5 wt.-%, most preferably in the range from 0.0 to 2.5 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more adhesion promoters (AP); e) optionally, an amount in the range from 0.0 to 10.0 wt.-%, more preferably in the range from 0.0 to 8.0, most preferably in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters; f) optionally, an amount in the range from 0.0 to 5.0 wt.-%, more preferably in the range from 0.0 to 3.5 wt.-%, most preferably in the range from 0.0 to 2.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more pigments (P); and g) optionally, an amount in the range from 0.0 to 30.0 wt.-%, more preferably in the range from 0.0 to 15.0 wt.-%, most preferably in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further additives (A), wherein the combined content of the one or more propylene-ethylene random copolymers (C3C2) and the one or more recycled polypropylenes (RPP) is in the range from 40.0 to 70.0 wt.-%, more preferably in the range from 45.0 to 68.0 wt.-%, most preferably in the range from 50.0 to 66.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC).

[0027] The combined content of the glass fibers (GF), the one or more propylene-ethylene random copolymers (C3C2), and the one or more recycled polypropylenes (RPP) is at least 60.0 wt.- %, in some embodiments at least 70.0 wt.-%, in further embodiments at least 80.0 wt.-%, and in yet further embodiments at least 90.0 wt.-%, relative to the total weight of the fiber- reinforced polypropylene composition (PC).

[0028] The individual components will now be described in more detail.

[0029] The one or more propylene-ethylene random copolymers (C3C2)

[0030] One essential component of the fiber-reinforced polypropylene composition (PC) is one or more propylene-ethylene random copolymers (C3C2).

[0031] Each of the propylene-ethylene random copolymers (C3C2) is formed from propylene monomer units and ethylene comonomer units. Any other comonomer units present are negligible and would result from impurities in the feeds of propylene and ethylene during polymerization, rather than the addition of a further comonomer feed. It is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 20 to 500 g / 10 min, more preferably in the range from 40 to 200 g / 10 min, most preferably in the range from 60 to 100 g / 10 min.

[0032] It is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a melting temperature (Tm), determined according to ISO 11357, in the range from 125.0 to 156.0 °C, more preferably in the range from 135.0 to 156.0 °C, most preferably in the range from 145.0 to 156.0 °C.

[0033] It is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a crystallization temperature (Tc), determined according to ISO 11357, in the range from 110.0 to 140.0 °C, more preferably in the range from 115.0 to 135.0 °C, most preferably in the range from 120.0 to 130.0 °C.

[0034] It is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has an ethylene (C2) content, determined by quantitative13C- NMR spectroscopy, in the range from 1.0 to 7.0 wt.-%, more preferably in the range from 2.0 to 6.0 wt.-%, most preferably in the range from 3.0 to 5.0 wt.-%.

[0035] It is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has not been visbroken. As such, it is preferred that at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) is / are free from radical initiators and decomposition products thereof.

[0036] The one or more recycled polypropylenes (RPP)

[0037] Another essential component of the fiber-reinforced polypropylene composition (PC) is the one or more recycled polypropylenes (RPP).

[0038] The one or more recycled polypropylenes (RPP) are polypropylene rich recycled materials, meaning that they comprise significantly more polypropylene than polyethylene. Recycled waste streams, which are high in polypropylene can be obtained from a number of commercial sources.

[0039] Preferably, the one or more recycled polypropylenes (RPP) are obtained from recycled waste by means of plastic recycling processes known in the art. Such recyclates are commercially available, e.g. from Corepla (Italian Consortium for the collection, recovery, recycling of packaging plastic wastes), Resource Plastics Corp. (Brampton, ON), Kruschitz GmbH, Plastics and Recycling (AT), Vogt Plastik GmbH (DE), Mtm Plastics GmbH (DE) etc. Non- exhaustive examples of polypropylene rich recycled materials include: Purpolen®PP (Mtm Plastics GmbH), Axpoly® recycled polypropylene pellets (Axion Ltd) and PolyPropylene Copolymer (BSP Compounds).

[0040] During recycling, any reasonable measure will usually be taken for any components other than polypropylene to be reduced / removed as far as the final application or use suggests such measures; however, other components are often present in small amounts.

[0041] Other such components include polyethylene (PE), polystyrene (PS), polyamides (PA), polyethylene terephthalate (PET), which are all present in as low an amount as possible, preferably below the detection limit.

[0042] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has a melt flow (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 10 to 500 g / 10 min, more preferably in the range from 15 to 450 g / 10 min, most preferably in the range from 18 to 400 g / 10 min.

[0043] In the production process for long glass fiber-reinforced polypropylene, it is preferred that the viscosity of the polypropylene is low.

[0044] One such was of ensuring low viscosity, i.e. high MFR2, is visbreaking, wherein a radical initiator, more preferably a peroxide radical initiator, is used to degrade the longer chain polymers, thus reducing the MFR2. In one particularly preferred embodiment, at least one of the one or more recycled polypropylenes (RPP) has been prepared via visbreaking. Such visbroken recycled polypropylenes typically have a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 75 to 500 g / 10 min, more preferably in the range from 100 to 450 g / 10 min, most preferably in the range from 150 to 400 g / 10 min.

[0045] In view of the viscosity requirements for producing long glass fiber-reinforced polypropylene compositions via pultrusion, it is preferred that at least one of the one or more propylene-ethylene random copolymers (C3C2) and the one or more recycled polypropylenes (RPP) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 75 to 500 g / 10 min, more preferably in the range from 100 to 450 g / 10 min, most preferably in the range from 150 to 400 g / 10 min. In some embodiments at least one of the one or more propylene-ethylene random copolymers (C3C2) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 75 to 500 g / 10 min, more preferably in the range from 100 to 450 g / 10 min, most preferably in the range from 150 to 400 g / 10 min. In other embodiments at least one of the one or more recycled polypropylenes (RPP) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 75 to 500 g / 10 min, more preferably in the range from 100 to 450 g / 10 min, most preferably in the range from 150 to 400 g / 10 min.

[0046] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has an ethylene content (C2(total)), determined by CRYSTEX QC analysis, in the range from 1.0 to 11.0 wt.-%, more preferably in the range from 1.5 to 9.0 wt.-%, most preferably in the range from 2.0 to 7.0 wt.-%.

[0047] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has a soluble fraction (SF) content, determined by CRYSTEX QC analysis, in the range from 2.0 to 17.0 wt.-%, more preferably in the range from 4.0 to 15.0 wt.-%, most preferably in the range from 6.0 to 13.0 wt.-%. At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has a crystalline fraction (CF) content, determined by CRYSTEX QC analysis, in the range from 83.0 to 98.0 wt.-%, more preferably in the range from 85.0 to 96.0 wt.-%, most preferably in the range from 87.0 to 94.0 wt.-%.

[0048] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has an ethylene content of the soluble fraction (C2(SF)), determined by CRYSTEX QC analysis, in the range from 5.0 to 35.0 wt.-%, more preferably in the range from 7.0 to 33.0 wt.-%, most preferably in the range from 10.0 to 30.0 wt.-%.

[0049] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has an ethylene content of the crystalline fraction (C2(CF)), determined by CRYSTEX QC analysis, in the range from 0.5 to 8.0 wt.-%, more preferably in the range from 1.0 to 6.0 wt.-%, most preferably in the range from 1.5 to 4.0 wt.-%.

[0050] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has an inorganic residue content, as determined by calcination analysis according to DIN ISO 1172: 1996, of O.OO to 1.70 wt.-%, more preferably in the range from 0.00 to 1.00 wt.-%, most preferably in the range from 0.00 to 0.30 wt.-%.

[0051] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably originates from post-industrial waste, post-consumer waste, or a mixture thereof, most preferably from post-consumer waste.

[0052] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has a limonene content, determined by headspace gas chromatography mass spectrometry (HS / GC / MS), in the range from 0. 10 to 150 ppm.

[0053] The presence of limonene is indicative that the one or more recycled polypropylenes (RPP) originates from post-consumer waste. Further indications of the recycled-nature of the one or more recycled polypropylenes (RPP) include the presence of other polymers, such as polystyrene and polyamide-6, and the presence of fatty acids.

[0054] Accordingly, it is further preferred that the one or more recycled polypropylenes (RPP) comprises one or more of polystyrene, polyamide-6 and fatty acids, preferably comprises each of polystyrene, polyamide-6 and fatty acids.

[0055] At least one of, preferably each of, the one or more recycled polypropylenes (RPP) preferably has a density, determined according to ISO 1183-187, in the range from 890 to 930 kg / m3, more preferably in the range from 900 to 920 kg / m3, most preferably in the range from 905 to 915 kg / m3.

[0056] The glass fibers (GF)

[0057] Another essential component of the fiber-reinforced polypropylene composition (PC) is the glass fibers (GF).

[0058] It is preferred that the glass fibers (GF) have a weighted average fiber length (Lp), determined according to DIN ISO 22314 on 400x200x2.5 mm3injection moulded plaques prepared according to the method given in the determination method for optical properties / surface aspect, in the range from 0.80 to 5.00 mm, more preferably in the range from 1.00 to 4.00 mm, most preferably in the range from 1.20 to 3.00 mm.

[0059] It is preferred that the glass fibers (GF) have a weighted average fiber length (Lp), determined according to DIN ISO 22314 on specimens of Tensile type 1A prepared in accordance with ISO 19069-2, in the range from 1.00 to 6.00 mm, more preferably in the range from 1.50 to 5.00 mm, most preferably in the range from 2.00 to 4.00 mm.

[0060] As explained above, reducing the length of the glass fibers or the amount of glass fibers is known to be a solution to the undesired surface defects; however, by reducing the length and / or amount of the glass fibers affects their ability to provide a beneficial balance of mechanical properties. As such, by optimizing the polymer design, it is possible to include high amounts of long glass fibers having increased length relative to other compositions having similar surface performance.

[0061] Although the polymer design of the present invention may be suitable for producing fiber- reinforced polypropylene compositions containing glass fiber derived from chopped glass fiber (i.e. short glass fiber), it is particularly useful for producing long-glass fiber reinforced polypropylene compositions having especially long glass fibers.

[0062] As such, it is preferred that the glass fibers are long glass fibers, i.e. introduced as continuous glass fibers. It is preferred that the fiber-reinforced polypropylene is obtainable, more preferably obtained via a pultrusion process, most preferably via the pultrusion process as described in EP 1 364 760 Bl.

[0063] The one or more adhesion promoters (AP)

[0064] Another of the optional components of the fiber-reinforced polypropylene composition (PC) is one or more adhesion promoters (AP). These adhesion promoters help to disperse the glass fibers within the fiber-reinforced polypropylene composition (PC) and chemically couple the glass fibers to the polypropylene used as matrix.

[0065] Each adhesion promoter (AP) preferably comprises, more preferably is, a modified (functionalized) polymer and optionally a low molecular weight compound having reactive polar groups.

[0066] Modified alpha-olefin polymers, in particular propylene homopolymers and copolymers, like copolymers of ethylene and propylene with each other or with other alpha-olefins, are most preferred, as they are highly compatible with the polymer of the present composite. Modified polyethylene and modified styrene block copolymers, like modified poly(styrcnc- / i- butadicnc- / ?-styrcnc) (SBS) or poly(styrcnc- / ?-(cthylcnc-cobutylcnc)- / ?-styrcnc) (SEBS), can be used as well. In terms of structure, the modified polymers are preferably selected from graft or block copolymers.

[0067] In this context, preference is given to modified polymers containing groups deriving from polar compounds, in particular selected from the group consisting of acid anhydrides, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl compounds, oxazoline and epoxides, and also ionic compounds.

[0068] Specific examples of the said polar compounds are unsaturated cyclic anhydrides and their aliphatic diesters, and the diacid derivatives. In particular, one can use maleic anhydride and compounds selected from Ci to Cio linear and branched dialkyl maleates, Ci to Cio linear and branched dialkyl fumarates, itaconic anhydride, Ci to Cio linear and branched itaconic acid dialkyl esters, maleic acid, fumaric acid, itaconic acid and mixtures thereof.

[0069] Particular preference is given to maleic anhydride functionalized polypropylene as adhesion promoter (AP).

[0070] Particular preference is given to an adhesion promoter (AP) being a modified propylene copolymer or, a modified propylene homopolymer the latter is especially preferred.

[0071] In one embodiment the adhesion promoter (AP) is a modified (random) propylene copolymer containing polar groups as defined above. In one specific embodiment the adhesion promoter (AP) is a (random) propylene copolymer grafted with maleic anhydride. Thus, in one specific preferred embodiment the adhesion promoter (AP) is a (random) propylene ethylene copolymer grafted with maleic anhydride, more preferably wherein the ethylene content based on the total amount of the random propylene ethylene copolymer is in the range of 1.0 to 8.0 wt.-%, more preferably in the range of 1.5 to 7.0 wt.-%.

[0072] The modified polymer, i.e. the adhesion promoter (AP), can be produced in a simple manner by reactive extrusion of the polymer, for example with maleic anhydride in the presence of free radical generators (like organic peroxides), as disclosed for instance in EP 0 572 028. Adhesion promoters are known in the art and may be commercially available. Suitable examples include SCONA TPPP 9012 GA and SCONA TPPP 8112 FA of BYK.

[0073] The one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters

[0074] Another of the optional components of the fiber-reinforced polypropylene composition (PC) is one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters.

[0075] In the broadest sense, these one or more further polymers may be any virgin polymers other than polypropylenes and adhesion promoters. Non limiting examples of such polymers that are routinely added to such fiber-reinforced compositions include ethylene-based polymers, for example HDPE, MDPE, LDPE, LLDPE, ethylene-based plastomers, and ethylene-based elastomers, wherein the ethylene-based polymers may be homopolymers, copolymers, or terpolymers, polystyrene, thermoplastic elastomers such as styrenic block copolymers (e.g. SEBS), and ethylene propylene diene monomer rubbers (EPDM).

[0076] The optional further virgin polymers (FP) do not include any further recycled polymers. Any recycled polymer, if present, is assigned to the one or more recycled polypropylenes (RPP). As such, any optional further virgin polymers (FP) are free from limonene, as determined by headspace gas chromatography mass spectrometry (HS / GC / MS).

[0077] The one or more pigments (P)

[0078] Another optional component of the fiber-reinforced polypropylene composition (PC) is the one or more pigments (P).

[0079] The choice of whether one or more pigments are present depends on the end application of the fiber-reinforced polypropylene composition (PC). The selection of one or more pigments suitable for the fiber-reinforced polypropylene composition (PC) is within the general knowledge of the person skilled in the art. Given that it is preferred that the fiber-reinforced polypropylene composition (PC) has a low CIELAB L* value, it is also preferred that at least one of the one or more pigments is a black pigment, more preferably carbon black (CB).

[0080] The one or more additives (A)

[0081] Another optional component of the fiber-reinforced polypropylene composition (PC) is the one or more further additives (A).

[0082] The selection of suitable additives for the fiber-reinforced polypropylene composition (PC) is within the general knowledge of the person skilled in the art.

[0083] For example, the one or more further additives (A) may be selected from the group consisting of antioxidants, stabilizers, flame retardants, fillers, nucleating agents, and antistatic agents.

[0084] Such additives are generally commercially available and are described, for example, in "Plastic Additives Handbook", pages 871 to 873, 5th edition, 2001 of Hans Zweifel.

[0085] It is understood that the content of additives (A), given with respect to the total weight of the fiber-reinforced polypropylene composition (PC), includes any carrier polymers used to introduce the additives to said fiber-reinforced polypropylene composition (PC), i.e. masterbatch carrier polymers. An example of such a carrier polymer would be a polypropylene homopolymer in the form of powder.

[0086] Any pigments present in the fiber-reinforced polypropylene composition do not count towards the content of one or more further additives, rather these are present as the one or more pigments (P), as described above. The fiber-reinforced polypropylene composition (PC)

[0087] It is preferred that the fiber-reinforced polypropylene composition (PC) has a crystallization peak width at 10% height (FW10%), as determined according to the method given in the determination methods, of at least 30.0 °C, more preferably of at least 35.0 °C, most preferably of at least 40.0 °C.

[0088] It is also preferred that the fiber-reinforced polypropylene composition (PC) has a crystallization peak width at 25% height (FW25%), as determined according to the method given in the determination methods, of at least 16.00 °C, more preferably of at least 18.00 °C, most preferably of at least 20.00 °C.

[0089] It is preferred that the fiber-reinforced polypropylene composition (PC) has a CIELAB L* value, as determined according to ISO 11664-4 on a 400x200x2.5 mm3injection moulded plaques prepared according to the method given in the determination method for optical properties / surface aspect, of less than or equal to 32, more preferably of less than or equal to 29, most preferably of less than or equal to 27.

[0090] The CIELAB L* parameter is an indication of how dark the fiber-reinforced polypropylene composition is. This is particularly relevant, since the surface defects caused by long glass fibers (as discussed above) are particularly visible when the composition is dark. That is not to say that these surface defects are not present for lighter-coloured compositions; however, they are simply less measurable by the methods used in the present application. As such, the problem of surface defects is a problem that is of relevance for all colours, but especially for dark coloured fiber-reinforced polypropylene compositions.

[0091] As mentioned above, the fiber-reinforced polypropylene compositions of the present invention have reduced surface defects, relative to compositions having similar amounts of glass fiber having a similar length.

[0092] It is thus preferred that the fiber-reinforced polypropylene composition (PC) has a histogram peak standard deviation, as determined according to the method given in the determination methods, in the range from 1.0 to 11.0, more preferably in the range from 3.0 to 10.0, most preferably in the range from 5.0 to 9.0.

[0093] This histogram peak standard deviation is an indication of the reduced surface defects, especially for dark compositions, as discussed above.

[0094] As mentioned above, the fiber-reinforced polypropylene compositions of the present invention have a beneficial balance of mechanical properties, relative to compositions having similar surface properties.

[0095] It is preferred that the fiber-reinforced polypropylene composition (PC) has a tensile modulus, determined according to ISO 527-2 on a specimen of Tensile type 1A, in the range from 5,000 to 20,000 MPa, more preferably in the range from 6,000 to 15,000 MPa, most preferably in the range from 7,000 to 12,000 MPa.

[0096] It is preferred that the fiber-reinforced polypropylene composition (PC) has a tensile strength, determined according to ISO 527-2 on a specimen of Tensile type 1A, in the range from 100 to 300 MPa, more preferably in the range from 110 to 250 MPa, most preferably in the range from 120 to 200 MPa.

[0097] It is preferred that the fiber-reinforced polypropylene composition (PC) has a Charpy Notched Impact Strength (NIS) at 23 °C, measured according to ISO 179-leA on 80x 10x4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 10 to 50 kJ / m2, more preferably in the range from 13 to 35 kJ / m2, most preferably in the range from 16 to 25 kJ / m2.

[0098] It is preferred that the fiber-reinforced polypropylene composition (PC) has a Charpy Unnotched Impact Strength (UNIS) at 23 °C, measured according to ISO 179-leU on 80x 10x4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 30 to 100 kJ / m2, more preferably in the range from 40 to 80 kJ / m2, most preferably in the range from 50 to 65 kJ / m2. It is preferred that the fiber-reinforced polypropylene composition (PC) has a puncture energy at +23 °C, measured according to ISO 6603-2 using injection-moulded plaques of 60x60x3 mm3and a test speed of 4.4 m / s, in the range from 9.0 to 40.0 J, more preferably in the range from 10.0 to 30.0 J, most preferably in the range from 11.0 to 20.0 J.

[0099] Process

[0100] Technologies for producing fiber-reinforced polypropylene compositions are well known in the art.

[0101] In the context of the present invention, it is preferred that the glass fiber is long glass fiber, i.e. introduced via a pultrusion method. In such a method, continuous glass fibers are impregnated and / or coated with a polymer matrix to produce strands, which may subsequently be cut into pellets. As a first approximation, the fibers in these pellets are aligned and have approximately the same length as the pellet.

[0102] There are many well-known pultrusion methods; however, in the context of the present invention, it is particularly preferred that the pultrusion is carried out according to the method as described in EP 1 364 760 Bl.

[0103] Article

[0104] In a second aspect, the present invention is directed to an injection moulded article comprising at least 90 wt.-%, relative to the total weight of the article, of the fiber-reinforced polypropylene composition (PC) of the first aspect.

[0105] The injection moulded article preferably comprises at least 95 wt.-%, more preferably at least 98 wt.-% of the fiber-reinforced polypropylene composition (PC) of the first aspect.

[0106] In one embodiment, the injection moulded article consists of the fiber-reinforced polypropylene composition (PC) of the first aspect. The injection moulded article is preferably an automotive interior article that is at least partially visible when installed in the vehicle, more preferably selected from the group consisting of tailgates, door module carriers, seat structures, dashboards and centre consoles. It is preferred that the glass fibers (GF) in the injection moulded article have a weighted average fiber length (Lp), determined according to DIN ISO 22314, in the range from 0.70 to 6.00 mm, more preferably in the range from 0.75 to 5.00 mm, most preferably in the range from 0.80 to 4.00 mm. It is preferred that the injection moulded article has a CIELAB L* value, as determined according to ISO 11664-4, of less than or equal to 32, more preferably of less than or equal to 29, most preferably of less than or equal to 27.

[0107] All fallback positions and preferred embodiments of the fiber-reinforced polypropylene composition (PC) of the first aspect apply mutatis mutandis to the second aspect.

[0108] E X A M P L E S

[0109] 1. Determination methods

[0110] The following definitions of terms and determination methods apply for the above general description of the invention including the claims as well as to the below examples unless otherwise defined.

[0111] Quantification of microstructure by NMR spectroscopy (propylene homopolymers) Quantitative13C{’H} NMR spectra were recorded in the solution-state using a Bruker A vance Neo 400MHz NMR spectrometer operating at 400.15 and 100.63 MHz for 'H and13C respectively. All spectra were recorded using a13C optimised 10 mm selective excitation probehead at 125 °C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 1 . 1 .2.2-tctrachlorocthanc / 2 (TCE-d2) using approximately 3 mg of 2,6-di-tert-buthyl-4-methylphenol (CAS 128-37-0) as stabiliser. Standard 90 degree single-pulse excitation was employed utilising the NOE, bi-level WALTZ 16 decoupling scheme, relaxation delay of 3 s and 10Hz sample rotation {zhou07,busico07}. A total of 6144 (6k) transients were acquired per spectra. This setup was chosen primarily for the high resolution needed for tacticity distribution quantification {busicoOl, busico97}.

[0112] 13C{’H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were internally referenced to the methyl signal of the isotactic pentad mmmm at 21.85 ppm.

[0113] The tacticity distribution was quantified through integration of the methyl region between 23.6 and 19.7 ppm correcting for any sites not related to the stereo sequences of interest {busicoOl, busico97}.

[0114] The pentad tacticity distribution was determined through direct separate integration of each methyl signal from a given steric pentad followed by normalisation to the sum of methyl signals from all steric pentads. The relative content of a specific steric pentad was reported as the mole fraction or percentage of a given steric pentad xxxx with respect to all steric pentads:

[0115] [xxxx] = xxxx / (mmmm + mmmr + rmmr + mmrr + xmrx + mrmr + rrrr + mrrr + mrrm) where xmrx represents the combined integral of both mmrm and rmrr as signal from these steric pentads are not commonly resolved. The pentad isotacticity was thus given by: [mmmm] = mmmm / (mmmm + mmmr + rmmr + mmrr + xmrx + mrmr + rrrr + mrrr + mrrm)

[0116] The triad tacticity distribution was indirectly determined from the pentad tacticity distribution using the known pentad-triad necessary relationships:

[0117] [mm] = [mmmm] + [mmmr] + [rmmr]

[0118] [mr] = [mmrr] + [xmrx] + [mrmr]

[0119] [rr] = [rrrr] + [mrrr] + [mrrm]

[0120] If 2,1 erythro regio defects were present, indicated by the two methyl sites at 17.6 and 17.2 ppm and confirmed by other characteristic sites {resconiOO}, the amount of 2,1 erythro regio defects was quantified using the average integral of the two characteristic methyl sites at 17.6 (Ie6) and 17.2 (Ies) ppm:

[0121] P21e = (Ie6 + leg) / 2

[0122] The amount of 1,2 primary inserted propene was quantified based on the methyl region (ICHS 22.5 ppm - 19.8 ppm) with correction undertaken for sites included in this region not related to primary insertion and for primary insertion sites excluded from this region (Pi2e = P2ie): P12 = lens + P12e

[0123] The total amount of propene was quantified as the sum of primary inserted propene and propene from 2.1 erythro regio defects:

[0124] P total = P12 + P21e

[0125] The mole percent of 2,1 erythro regio defects was quantified with respect to all propene: [2.1e] mol-% = 100 * (P2ie / Ptotai) busicoOl - Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443 busico97 - Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30 (1997) 6251 zhou07 - Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B„ J. Mag. Reson. 187 (2007) 225 busico07 - Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128 resconiOO - Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253 Quantification of microstructure by NMR spectroscopy (C3C2 copolymers)

[0126] Quantitative13C{’H} NMR spectra were recorded in the solution-state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for 'H and13C respectively. All spectra were recorded using a13C optimised 10 mm extended temperature probehead at 125 °C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of l,2-tetrachloroethane-d2 (TCE-d2) along with chromium - (Ill)-acetylacetonate (Cr(acac)s) resulting in a 65 mM solution of relaxation agent in solvent {singh09} . To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme{zhou07,busico07}. A total of 6144 (6k) transients were acquired per spectra.

[0127] Quantitative13C{’H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed {wangOO, cheng84, randall89}.

[0128] The comonomer fraction was quantified using the method of Wang et. al. {wangOO} through integration of multiple signals across the whole spectral region in the13C{’H} spectra. This method was chosen for its robust nature and ability to account for the presence of regiodefects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents.

[0129] The mole percent comonomer incorporation was calculated from the mole fraction: E [mol-%] = 100 * fE

[0130] The weight percent comonomer incorporation and propylene was calculated from the mole fraction:

[0131] E [wt.-%] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1-fE) * 42.08)) P [wt.-%] = 100 * ((1-fE) * 42.08) / ((fE * 28.06) + ((1-fE) * 42.08)) If 2, 1 erythro regio defects were present, indicated by the two methyl sites at 17.7 ppm and 17.3 ppm and confirmed by other characteristic sites {resconiOO}, the amount of 2,1 erythro regio defects was quantified using the average integral of the two characteristic methyl sites at 17.7ppm (Iee) and 17.3 (Ies) ppm:

[0132] P21e = (Ie6 + leg) / 2

[0133] The amount of 1,2 primary inserted propene was quantified based on the methyl region (ICHS 22.5 ppm - 19.8 ppm) with correction undertaken for sites included in this region not related to primary insertion and for primary insertion sites excluded from this region (Pi2e = P2ie): P12 = IcH3 + P12e

[0134] The total amount of propene was quantified as the sum of primary inserted propene and propene from 2.1 erythro regio defects:

[0135] P total = P12 + P21e

[0136] The mole percent of 2,1 erythro regio defects was quantified with respect to all propene: [2.1e] mol-% = 100 * (P2ie / Ptotai) busicoOl - Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443 busico97 - Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30 (1997) 6251 zhou07 - Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D.

[0137] Winniford, B„ J. Mag. Reson. 187 (2007) 225 busico07 - Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128 resconiOO - Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253 wangOO - Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157 cheng84 - Cheng, H. N., Macromolecules 17 (1984), 1950 singh09 - Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475 kakugo82 - Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150 randall89 - Randall, J. Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201. CRYSTEX QC analysis

[0138] All CRYSTEX QC analysis was carried out according to the method described in WO 2024 / 184334 Al.

[0139] Quantification of microstructure by NMR spectroscopy (for CRYSTEX calibration) Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used for calibration.

[0140] Quantitative13C {1H } NMR spectra were recorded in the solution-state using a Bruker Avance Neo 400 NMR spectrometer operating at 400.15 and 100.62 MHz for 'H and13C respectively. All spectra were recorded using a13C optimized 10 mm extended temperature probe head at 125 °C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in approximately 3 ml of l,2-tetrachloroethane-d2 (TCE-d2) along with approximately 3 mg BHT (2,6-di-tert-butyl-4-methylphenol CAS 128-37-0) and chromium-(III)-acetylacetonate (Cr(acac)3) resulting in a 60 mM solution of relaxation agent in solvent as described in G. Singh, A. Kothari, V. Gupta, Polymer Testing 2009, 28(5), 475.

[0141] To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme as described in Z. Zhou, R. Kuemmerle, X. Qiu, D. Redwine, R. Cong, A. Taha, D. Baugh, B. Winniford, J. Mag. Reson. 187 (2007) 225 and V. Busico, P. Carbonniere, R. Cipullo, C. Pellecchia, J. Severn, G. Talarico, Macromol. Rapid Commun. 2007, 28, 1128. A total of 6144 (6k) transients were acquired per spectra.

[0142] Quantitative13C{’H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present.

[0143] Characteristic signals corresponding to the incorporation of ethylene were observed (as described in Cheng, H. N., Macromolecules 1984, 17, 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer: fE = ( E ) / ( P + E )

[0144] The comonomer fraction was quantified using the method of W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157, through integration of multiple signals across the whole spectral region in the13C{’H} spectra. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents.

[0145] The mole percent comonomer incorporation was calculated from the mole fraction:

[0146] E [mol-%] = 100 * fE

[0147] The weight percent comonomer incorporation was calculated from the mole fraction: E [wt.-%] = 100 * ( fE * 28.06 ) / ( (fE * 28.06) + ((1-fE) * 42.08) ).

[0148] Melt Flow Rate

[0149] The melt flow rate (MFR) was determined according to the method described in WO 2024 / 184334 Al.

[0150] The xylene soluble fraction at room temperature (XCS, wt.-%): The amount of the polymer soluble in xylene was determined at 25 °C according to ISO 16152 (2022).

[0151] DSC analysis, melting temperature (Tm) and heat of fusion (Hf), crystallization temperature (Tc) and heat of crystallization (Hc): measured with a TA Instrument Q200 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC was run according to ISO 11357 / part 3 / method C2 in a heat / cool / heat cycle with a scan rate of 10 °C / min in the temperature range of -30 to +225 °C. Crystallization temperature (Tc) and crystallization enthalpy (Hc) were determined from the cooling step, while melting temperature (Tm) and melting enthalpy (Hm) were determined from the second heating step.

[0152] DSC peak width

[0153] A TA Instruments Q200 Differential Scanning Calorimeter was used as calibrated with Indium, Zinc, and Tin and operating under 50 mL / min of nitrogen flow. The employed thermal program consisted of a first heating step to 225 °C to erase the previous thermal history and a cooling step at 10 °C / min. The melting behavior was obtained by performing a second heating scan to 225 °C at 10 °C / min. The melting temperature was taken as the peak value from the second heating scan. The DSC trace was integrated from 30 °C to the end of the melting peak. The heat flow at melting was evaluated as the heat flow measured at the peak melting temperature and subtracting the value at the same temperature at the baseline. This value was multiplied by 0. 1 (i.e., 10%) and the temperatures before and after the melting peak at which this value was reached, after baseline subtraction, were recorded. The difference between these two temperatures was taken as a measure of the broadness of the DSC melting trace and indicated as FW10%. The method for determining FW25% is analogous (with a factor of 0.25 instead of O. l).

[0154] Inorganic residues

[0155] Inorganic residues were quantified according to the method described in WO 2024 / 184334 Al.

[0156] Limonene detection

[0157] The determination of limonene was carried out according to the method described in WO 2024 / 184334 Al.

[0158] Tensile Properties

[0159] The tensile properties were determined according to ISO 527-2:2012, on a specimen of Tensile type 1A prepared in accordance with ISO 19069-2 using a melt temperature of 250 °C and 10 bar specific back pressure during dosing.

[0160] Charpy impact strength (NIS and UNIS)

[0161] The Charpy notched impact strength (NIS) was measured according to ISO 179 leA at +23 °C, using injection moulded bar test specimens of 80x 10x4 mm3prepared in accordance with ISO 19069-2 using a melt temperature of 250 °C and 10 bar specific back pressure during dosing. The Charpy unnotched impact strength (UNIS) was measured according to ISO 179 leU at +23 °C, using injection moulded bar test specimens of 80x 10x4 mm3prepared in accordance with ISO 19069-2 using a melt temperature of 250 °C and 10 bar specific back pressure during dosing. Puncture energy and Energy to max Force

[0162] Puncture energy and Energy to max Force were determined on plaques with dimensions 60 x 60 x 3 mm3prepared in accordance with ISO 19069-2 using a melt temperature of 250 °C and 10 bar specific back pressure during dosing using impact testing according to ISO 6603-2. The test was performed at +23 °C with a lubricated tip with a diameter of 20 mm and impact velocity of 4.4 mm / s.

[0163] CIELAB

[0164] The method was used for measurement of color on injection moulded pieces or plaques and complies with ISO 11664-4 (2019). With a spectrophotometer, the 3 standard color value values X, Y and Z are measured, which are used to calculate the CIE L*, a*, b* and its color distances.

[0165] CIELAB measurements were carried out on 400x200x2.5 mm3injection moulded plaques prepared according to the method below for optical properties / surface aspect.

[0166] Spiral flow properties

[0167] Spiral Test was carried out using an Engel 1050 / 250 HL injection moulding apparatus

[0168] Machine details:

[0169] Clamping Force: 2501

[0170] Screw Diameter: 55mm

[0171] Maximum Injection Pressure: 2050 bar

[0172] Maximum Shot Volume: 510 cm3

[0173] Maximum Opening Stroke: 850mm

[0174] Min. to Max. Installation Height: 200mm - 800mm

[0175] Maximum Ejector Stroke: 200mm

[0176] Maximum Contact Pressure of Nozzle: 67kN

[0177] Amount of Corepullings: 3

[0178] Amount of Cooling Circles: 6 NS / 6 ES (with an option to 10) Clamping force: 2501 Injection moulding tool:

[0179] The tool cavity is designed in a spiral form starting from the central gating point with a length of 1450mm. The cavity has a trapezoid cross section with 20. 16mm2, the cavity has a height of 2. 1mm leading to an at about 2.0mm thickness of the specimen.

[0180] There are markers every 10mm in the cavity surface to be able to identify the flow length.

[0181] Injection moulding parameters:

[0182] The injection moulding cylinder is heated to the following temperature profde:

[0183] Zone 6=200 °C / zone 5=220 °C / zone 4=220 °C / zone 3=230 °C / zone 2=230 °C / die =230 °C

[0184] The injection moulding tool is kept on 40 °C.

[0185] The moulding cycle is defined as follows:

[0186] Injection time: 3s

[0187] Packing time: 3s

[0188] Cooling time: 15s

[0189] Screw speed: 50mm / s

[0190] Dosing stroke: 60mm

[0191] Maximum injection pressure and packing pressure are equal and defined as 1400bar, lOOObar and 600bar.

[0192] The test result is the length the cavity is filled (flow length) measured from 10 parallels at a certain maximum injection pressure / packing pressure together with the mass temperature (230 °C) and the tool temperature (40 °C).

[0193] Shrinkage

[0194] Preparation of specimen:

[0195] The shrinkage specimen sector (radius of 320 mm, opening angle of 20°) and the stripe (340 x 66 mm2), both with a thickness of 2.8 mm, were produced using an Engel ES 1350 / 350 injection moulding machine. The specimens were filled through a gate located at the base of both the sector and the stripe. The process utilized a melt temperature of 240 °C, a mould temperature of 25 °C, and an injection time (f) of 3.5 seconds. To set the holding pressure PN, diagrams of the cavity pressure near to the gate (png) and far from the gate (prg) over time were used, PN was the pressure needed to achieve an average cavity pressure pavof 400 bar at the time tavwith png= cavity pressure near the gate

[0196] Pfg = cavity pressure far from the gate t^ = time until the cavity pressure far from the gate is 0 bar t = injection time

[0197] The holding pressure time is defined as

[0198] A holding pressure profile is implemented by splitting the holding pressure duration into 10 equal intervals, labeled tl to tlO, following this scheme:

[0199] The cooling time is defined as tk=2 x tN

[0200] The whole process setup procedure always ensures the same conditions in the mould, especially in terms of cavity pressure, to provide comparable process shrinkage. Measurement:

[0201] A pattern of circular dots was created on the plates using eroded spots with a diameter of 1 mm, spaced 5 to 10 mm apart. This pattern is recorded immediately after de-moulding using an OGP Smartscope Flash 400 optical gauging system to ensure proper contrast. The original mould pattern serves as the dimensional reference. After 96 hours at 23 °C, the post-shrinkage moulding pattern is determined using the optical gauging system, and all deviations of point- to-point distances are recorded. An average is calculated from three sets of values (three sectors and three stripes). Measuring points along the edges are excluded to avoid the influence of varying shear profiles along the sample borders.

[0202] For calculating the isotropic area shrinkage, a number of measuring points is connected by vectors and the resulting area determined, with A being the area after 96 h and Ao the area of the original pattern. The isotropic area shrinkage, Siso, is then calculated as

[0203] [ A

[0204] Sis°= 1- JsT

[0205] For determining linear shrinkage in cross flow direction and in flow direction the distances of gauge marks (measuring points) on the samples perpendicular and parallel to the melt flow direction are measured, thereby creating a set of h distances. The set of lo distances are the distances of the original pattern.

[0206] Shrinkage cross flow and in flow is calculated as Fasep Lp

[0207] For the determination of glass fiber length, the polymer matrix was first incinerated. The remaining ash was transferred to an aqueous solution which was diluted to a desired fibers per volume level. This solution as imaged by a high performance scanner. The images were analyzed by a software that segmented each individual fiber automatically and calculated each length.

[0208] The incineration was done thermogravimetrically in an oven at 625 °C until weight constancy.

[0209] The ash remaining in the crucible was transferred into purified water and properly diluted for image acquisition.

[0210] For image acquisition and analysis, the method FASEP (IDM Systems, Germany) was applied.

[0211] The scanner was operated at 2400 dpi in bright field mode. A LED light box was used to increase contrast between glass fibers and surrounding medium.

[0212] Fiber clusters in case of long glass fiber compounds were separated into individual fibers by using the fiber tracking algorithm (FASEP method ‘Ultra’).

[0213] The shortest fibers that can be detected with the chosen settings are ca. 54 pm long.

[0214] The amount of fibers that were analyzed are ca. 5000.

[0215] From all segmented fibers, average (In) and weighted average (Ip) lengths were calculated according to ISO 22314:

[0216] Values reported as Fasep Lp(l) were measured on specimens of Tensile type 1A prepared in accordance with ISO 19069-2, whilst Fasep Lp(2) values were measured on 400x200x2.5 mm3injection moulded plaques prepared according to the method given below for optical properties / surface aspect. Screening of organic emissions by thermo-desorption analysis

[0217] This method describes the semi-quantitative determination of organic compounds emitting from polyolefins. It is similar to the VDA 278 (October 2011) but includes specific adjustments. Directly after the production, the sample (injection moulded plaque, DIN-A5) was sealed in an aluminium -coated polyethylene bag and provided to the lab within 14 days. In the lab, it was stored openly for 7 days below 25 °C. After this period, an aliquot of 60 ± 5 mg was prepared from the stored sample. Trimming the aliquot should aim for a maximum coherent area. It was not the aim to create the largest possible surface area by cutting the aliquot into smaller pieces. The diameter of the sample injection tube should be used first. Length and thickness should be chosen accordingly, considering the specified aliquot weight. The aliquotwas directly desorbed using heat and a flow of helium gas. Volatile and semivolatile organic compounds were extracted into the gas stream and cryo-focused prior to the injection into a gas chromatographic (GC) system for analysis. The method comprised two extraction stages: In the analysis of low-boiling substances (LBS) the aliquot was desorbed at 90 °C for 30 min to determine volatile organic compounds in the boiling / elution range up to n-C25 (n-pentacosane). The analysis of high-boiling substances (HBS) involved a further desorption step of the same aliquot at 120 °C for 60 min to determine semi -volatile compounds in the boiling / elution range from n-C14 (n-tetradecane) to n-C32 (n- dotriacontane).

[0218] Similar to the VOC and FOG value in the VDA 278, the LBS was calculated as toluene equivalent (TE) and the HBS was calculated as hexadecane equivalent (HE) applying a semiquantitation and a respective calibration. The result was expressed in “pg / g”

[0219] Integration parameters for the LBS and HBS evaluation were chosen in such way that the „area reject“ corresponds to the area of 1 pg / g (TE and HE, respectively). Thus, smaller peaks do not add to the semi-quantitative result. The GC oven program was kept the same, no matter if a calibration run, an LBS run or an HBS run was performed. It started at 50 °C (1 min hold), followed by a ramp of 10 °C / min and an end temperature of 320 °C (10 min hold). For the GC column an Agilent DB5: 50 m x 250 pm x 0.25 pm (or comparable) was used. The method requires a Thermal Desorption System TDS 3 (Gerstel) and a Cooled Injection System CIS 4 (Gerstel) as well as a GC system with a flame ionisation detector (FID) but does not involve a mass spectrometer. Instead of 280 °C the CIS end temperature is always set to 380 °C. Optical Properties / Surface aspect

[0220] (400x200x2.5)mm3injection moulded plaques were used for surface aspect testing. The front surface of each plaque featured three distinct sections with different surface textures (see image below, step A): grain K09 (Volkswagen interior), grain K50 (Volkswagen interior), and a high-gloss polished finish. The back side of the plaque was also high-gloss polished.

[0221] The plaques were manufactured on a ENGEL e-motion 2440 / 380T injection moulding machine utilising a single-sided film gate that spanned the entire width of the plaque and a triangle sprue with a thickness of 4mm. The injection moulding machine was equipped with a screw (0 55 mm) suitable for the conversion of glass-fiber reinforced polypropylene.

[0222] The melt- and tool temperature were set to 230 °C and 40 °C. A specific back pressure of 150 bar, an injection time of 3 sec and a plasticizing speed of 0,3 m / s were utilised to produce the plaques. The switchover volume, holding pressure time, hold pressure and cooling time were adjusted for each material.

[0223] A picture of the high-gloss polished back side surface of the plaques was taken with a Epson Scanner Expression 12000X1 applying a resolution of 200 DPI and 8 bytes grey scale (see image below, step B. The grey scale of the image is calibrated with a TE165-A scale test chart BT.709 from the company Image Engineering. The 8 bytes grey scale is correlated to the gamma 0.45 in % as shown in the following chart: A Vision software from Lab VIEW is used for post processing the image. A representative section of 3095 x 1520 pixels was selected for the evaluation. Then the histogram tool is used to calculate the mean and the standard deviation of the histogram (see Figure 2).

[0224] Total volume of organic compounds (TVOC):

[0225] The TVOC value (also known as total carbon emission) was determined according to VDA 277 January 1995.

[0226] B. Experimental

[0227] 1. Catalysts

[0228] The following catalysts were used for the polymerization of the polypropylenes employed in the following compositions:

[0229] ZNC

[0230] A Ziegler-Natta type catalyst as used in for the inventive examples of WO2016 / 066446 Al was employed (without any vinylcyclohexane prepolymerization, unless vinylcyclohexane prepolymerization is specified).

[0231] This catalyst system was used in combination with triethyl-aluminium (TEAL) as co-catalyst and dicyclopentadienyl-dimethoxy silane (Donor D) as external donor.

[0232] SSC

[0233] ICS4 of WO 2020 / 239598 Al, which is based on metallocene catalyst rac-anti- dimethylsilanediyl[2-methyl-4,8-bis-(3’,5’-dimethylphenyl)-l,5,6,7-tetrahydro-s indacen-1- yl] [2 -methyl -4-(3 ’ ,5 ’ -dimethylphenyl)-5 -methoxy-6-tert-butylinden- 1 -yl] zirconium dichloride. 2. Propylene random copolymers and propylene homopolymers

[0234] The polymerizations of the propylene-ethylene random copolymers have been effected under the following conditions.

[0235] Table 1 Polymerization conditions for the propylene-ethylene random copolymers

[0236] * PVCH-prepolymerized catalyst & 0. 1 wt.-% talc added in stabilization Each propylene-ethylene random copolymer was compounded in a co-rotating twin-screw extruder Coperion ZSK 40 at 220 °C with 0.05 wt.-% of pentaerythrityl-tetrakis(3-(3 ’,5 ’-ditert. butyl -4-hydroxyphenyl)-propionate, (available as Irganox 1010 from BASF AG, Germany; CAS-no. 6683-19-8), and 0.10 wt.-% of tris (2,4-di-t-butylphenyl) phosphite, (available as Irgafos 168 from BASF AG, Germany; CAS-no. 31570-04-4), as well as (for C3C2-1 only) 1.0 wt.-% of a propylene homopolymer (available as HF955MO from Borealis AG, Austria). For C3C2-1, C3C2-2a, and C3C2-2b, an appropriate amount (i.e. enough to achieve the target MFR2 of 375 g / 10 min (for C3C2-1 and C3C2-2a), or of 450 g / 10 min (for C3C2-2b)) of peroxide 2,5-bis(tert.-butylperoxy)-2,5-dimethylhexane (available as Luperox 101 from Arkema, France; CAS-No. 78-63-7) was added.

[0237] After compounding and optionally visbreaking, the propylene-ethylene random copolymers had the following properties:

[0238] Table 2 Properties of the propylene-ethylene random copolymers h-PPl is the commercially available grade HL504FB (Borealis AG, Austria) and has an MFR2 of 450 g / 10 min, an XCS content of 1.10 wt.-%, a Tm of 162 °C, a Tc of 122 °C, a 2,1 -regiodefect content of less than 0.01 mol-% (i.e. is ZN-catalyzed), and a pentad isotacticity of 94.5 mol-%. h-PP2 is the commercially available grade HJ120UB (Borealis AG, Austria) and has an MFR2 of 75 g / 10 min, an XCS content of 1.25 wt.-%, a Tm of 162 °C, a Tc of 116 °C, a 2,1- regiodefect content of less than 0.01 mol-% (i.e. is ZN-catalyzed), and a pentad isotacticity of 94.5 mol-%. 3. Post-consumer recyclate (PCR)

[0239] The post-consumer recyclate (PCR) was obtained from a German post-consumer plastic waste stream, fulfilling the specification DSD324. This feedstock, provided in the form of bales, underwent a bale opening process and was then fed to a vibro-sieve separating over- (> 400 mm) and undersize (< 30 mm) fractions and then subjected to multiple sorting steps based on NIR and color in a cascade of 4 Tomra Autosort units. The generated high-quality fraction consisting of colourless PP material was then subjected to a hot caustic-soda (min. 0.5 wt.% NaOH, 80 °C) washing line based on the Krones Metapure W design, followed by mechanical drying, thermal drying, windsifting, screening (material < 2mm is separated) and a two-step flake sorting using Tomra Autosort Flake units and subsequent extrusion. The resultant pellets were then visbroken in in a co-rotating twin-screw extruder Coperion ZSK 40 at 220 °C with an appropriate amount of peroxide 2,5-bis(tert.-butylperoxy)-2,5- dimethylhexane (available as Luperox 101 from Arkema, France; CAS-No. 78-63-7) to adjust the MFR2 from 21 g / 10 min to 250 g / 10 min. The properties of the visbroken postconsumer recyclate (PCR) are given in Table 3.

[0240] Table 3 Properties of post-consumer recyclate (PCR)

[0241] The post-consumer recyclate (PCR) further comprises minor amounts of polystyrene, polyamide-6 and fatty acids. 4. Compounding of Comparative and Inventive Examples

[0242] The compositions for the inventive and comparative examples were prepared according to the recipes in Table 3. The properties of the resultant compositions are given in Table 4.

[0243] The fiber-reinforced compositions of CE1 to CE5, IE1 and IE2 were obtained in a two step process as described in EP 1 364 760 Bl. The rovings were impregnated in a first step and the impregnated rovings were coated by a coating die in a second step to produce strands. The strands were produced with a speed of 50-60 m / min and were immediately after production pulled through a water bath for solidifying them for proper handling. The solidified strands were then dried from the cooling bath water and processed through a pelletizer where they were cut into granules with a length of 12.5mm.

[0244] The following components were additionally employed in Table 4:

[0245] LGF continuous glass fibers with a trade name of Performax SE4849-1200, commercially available from Owens Coming Composites (US).

[0246] MAH-PP a maleic anhydride-grafted polypropylene with a trade name of Scona TPPP 9012 GA, commercially available from BYK Co. Ltd (DE).

[0247] CBMB 1 A carbon black masterbatch with a trade name of Masterminds PE black

[0248] 8006, having a carbon black content of 30 wt.-%, commercially available from QolorTech bv (NL).

[0249] CBMB2 A carbon black masterbatch with a trade name of UCC 36-97831909- SOUL-NA, having a pigment content of 25 wt.-%, commercially available from UCC - Audia Plastics (US).

[0250] AO1 Tris (2,4-di-t-butylphenyl) phosphite, commercially available as Irgafos

[0251] 168 from BASF AG, Germany; CAS-no. 31570-04-4. A02 Pentaerythrityl-tetrakis(3 -(3 ’ ,5 ’ -di -tert, butyl -4-hydroxyphenyl)- propionate, commercially available as Irganox 1010 from BASF AG, Germany; CAS-no. 6683-19-8.

[0252] AO3 Octadecyl 3-(3’,5’-di-tert-butyl-4-hydroxyphenylpropionate, commercially available as Irganox 1076 from BASF AG, Germany; CAS-no. 2082-79-3.

[0253] UV1 A UV-stabilizer masterbatch commercially available from Cytec (USA), under the trade name Cyasorb UV-3508PP5.

[0254] NU1 Sodium 2,2 ’-methylene bis(4,6-di-tert-butylphenyl) phosphate, commercially available as ADK STAB NA-11 UH from Adeka Corporation (DE); CAS-no. 85209-91-2.

[0255] Table 3 Recipes of Comparative and Inventive Examples Table 4 Properties of Comparative and Inventive Examples

[0256] * = Shrinkage measurement

[0257] As can be seen from Tables 3 and 4, the CE3 to CE5 represent an improvement over the compositions typical in the art, i.e. CE1 and CE2 employing one or more Ziegler-Natta catalyzed homopolymers. This is evidenced by the improved surface properties (see HistogramSD). Furthermore, the excellent balance of mechanical properties of CE1 and CE2 is maintained in CE3 to CE5. IE1 and IE2, which include post-consumer recy elate, have even better surface properties than the random copolymer-based examples CE3 to CE5, which is very surprising, given that recyclate-containing compositions are generally expected to have worse surface properties than composition containing only virgin materials. The balance of mechanical properties is not quite as good as CE3 to CE5; however, this is significantly higher than would be achievable by reducing the content and / or length of the glass fibers. Finally, by using high amounts of recycled polypropylene, the inventive fiber- reinforced polypropylene compositions are more environmentally friendly and help to comply with ever stricter regulations regarding the incorporation of recycled material into various end products.

Claims

C L A I M S1. A fiber-reinforced polypropylene composition (PC) that comprises: a) an amount in the range from 10.0 to 60.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more propyleneethylene random copolymers (C3C2); b) an amount in the range from 10.0 to 60.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more recycled polypropylenes (RPP); c) an amount in the range from 20.0 to 50.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of glass fibers (GF); d) optionally, an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more adhesion promoters (AP); e) optionally, an amount in the range from 0.0 to 10.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further virgin polymers (FP) other than polypropylenes and adhesion promoters; f) optionally, an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more pigments (P); and g) optionally, an amount in the range from 0.0 to 30.0 wt.-%, more preferably in the range from 0.0 to 15.0 wt.-%, most preferably in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC), of one or more further additives (A), wherein the combined content of the one or more propylene-ethylene random copolymers (C3C2) and the one or more recycled polypropylenes (RPP) is in the range from 40.0 to 70.0 wt.-%, relative to the total weight of the fiber-reinforced polypropylene composition (PC).

2. The fiber-reinforced polypropylene composition (PC) according to claim 1, wherein at least one of, preferably each of, the one or more recycled polypropylenes (rPP)has a limonene content, determined by headspace gas chromatography mass spectrometry (HS / GC / MS), in the range from 0.10 to 150 ppm.

3. The fiber-reinforced polypropylene composition (PC) according to claim 1 or claim 2, wherein at least one of, preferably each of, the one or more recycled polypropylenes (rPP) originates from post-consumer waste, post-industrial waste, or a mixture thereof, most preferably at least one of, preferably each of, the one or more recycled polypropylenes (rPP) originates from post-consumer waste.

4. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, wherein at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 20 to 500 g / 10 min, more preferably in the range from 40 to 200 g / 10 min, most preferably in the range from 60 to 100 g / 10 min.

5. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, wherein at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a melting temperature (Tm), determined according to ISO 11357, in the range from 125.0 to 156.0 °C, more preferably in the range from 135.0 to 156.0 °C, most preferably in the range from 145.0 to 156.0 °C.

6. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, wherein at least one of, preferably all of, the one or more propylene-ethylene random copolymers (C3C2) has a crystallization temperature (Tc), determined according to ISO 11357, in the range from 110.0 to 140.0 °C, more preferably in the range from 115.0 to 135.0 °C, most preferably in the range from 120.0 to 130.0 °C.

7. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, wherein at least one of, preferably all of, the one or morepropylene-ethylene random copolymers (C3C2) has an ethylene (C2) content, determined by quantitative13C-NMR spectroscopy, in the range from 1.0 to 7.0 wt.- %, more preferably in the range from 2.0 to 6.0 wt.-%, most preferably in the range from 3.0 to 5.0 wt.-%.

8. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, wherein the glass fibers (GF) have a weighted average fiber length (Lp), determined according to DIN ISO 22314 on a 400x200x2.5 mm3injection moulded plaques prepared according to the method given in the determination method for optical properties / surface aspect, in the range from 0.80 to 5.00 mm, more preferably in the range from 1.00 to 4.00 mm, most preferably in the range from 1.20 to 3.00 mm.

9. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, having a peak width at 10% height (FW10%), as determined according to the method given in the determination methods, of at least 30.0 °C, more preferably of at least 35.0 °C, most preferably of at least 40.0 °C.

10. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims having a CIELAB L* value, as determined according to ISO11664-4 on a 400x200x2.5 mm3injection moulded plaques prepared according to the method given in the determination method for optical properties / surface aspect, of less than or equal to 32, more preferably of less than or equal to 29, most preferably of less than or equal to 27.

11. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims having a histogram peak standard deviation, as determined according to the method given in the determination methods, in the range from 1.0 to 11.0, more preferably in the range from 3.0 to 10.0, most preferably in the range from 5.0 to 9.0.

12. The fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims having one or more, preferably all, of the following properties: a) a tensile modulus, determined according to ISO 527-2 on a specimen of Tensile type 1A, in the range from 5,000 to 20,000 MPa, more preferably in the range from 6,000 to 15,000 MPa, most preferably in the range from 7,000 to 12,000 MPa; b) a Charpy Notched Impact Strength (NIS) at 23 °C, measured according to ISO 179-leA on 80x 10x4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 10 to 50 kJ / m2, more preferably in the range from 13 to 35 kJ / m2, most preferably in the range from 16 to 25 kJ / m2; c) a Charpy Unnotched Impact Strength (UNIS) at 23 °C, measured according to ISO 179-leU on 80x 10x4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 30 to 100 kJ / m2, more preferably in the range from 40 to 80 kJ / m2, most preferably in the range from 50 to 65 kJ / m2; d) a puncture energy at +23 °C, measured according to ISO 6603-2 using injection- moulded plaques of 60x60x3 mm3and a test speed of 4.4 m / s, in the range from 9.0 to 40.0 J, more preferably in the range from 10.0 to 30.0 J, most preferably in the range from 11.0 to 20.0 J.

13. An injection moulded article comprising at least 90 wt.-%, relative to the total weight of the article of the fiber-reinforced polypropylene composition (PC) according to any one of the preceding claims, preferably an automotive interior article that is at least partially visible when installed in the vehicle, more preferably selected from the group consisting of tailgates, door module carriers, seat structures, dashboards and centre consoles.

14. The injection moulded article according to claim 13, wherein the glass fibers (GF) have a weighted average fiber length (Up), determined according to DIN ISO 22314, in the range from 0.70 to 6.00 mm, more preferably in the range from 0.75 to 5.00 mm, most preferably in the range from 0.80 to 4.00 mm.

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