Patent Description:
High melt flow polypropylenes are suitable for the production of fiber reinforced composites used e.g. in the automotive industry.

One of the fundamental problems in polymer business is recycling. At the moment, the market for recyclates, particularly recyclates from household trash, commonly denoted PCR ('post-consumer resins') is somewhat limited. Starting from household trash, the sorting and separation processes employed will not allow preparing pure polymers, i.e. there will always be some contaminants, or the processes may even result in blends of different polymers. When it comes to polyolefins, which constitute the vast majority of the polymer fraction of the collected household trash, a perfect separation of polypropylene and polyethylene is hardly possible. Recycled polyolefin materials, particularly post-consumer resins, are conventionally cross-contaminated with non-polyolefin materials such as polyethylene terephthalate, polyamide, polystyrene or non-polymeric substances like wood, paper, glass or aluminum. Even worse, those post-consumer recycled polyolefin materials are readily available on a multi-ton scale but unfortunately have limited mechanical properties and frequently severe odor and/or emission problems.

For fiber reinforced applications polypropylene compositions are required which have a high melt flow rate in order to prevent fiber breakage. At the same time balanced mechanical properties in high stiffness and strength are required. 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.

However, there is a deeply felt need for allowing the dumping and reuse of post-consumer polyolefin recyclates in final products without health and safety hazards.

The present invention is based on the surprising finding that by carefully selecting the propylene homopolymer based virgin components in polypropylene based compositions, which contain mixed plastics polypropylene-based blends originating from post-consumer recycled polyolefin streams, polypropylene based compositions with a superior balance of properties in regard of impact properties and especially mechanical properties, such as in tensile properties, and flowability, shown in a high melt flow rate. Thus, the compositions of the invention comprising mixed plastics polypropylene-based blends originating from post-consumer recycled polyolefin streams qualify for moulding applications and fiber reinforced composites, especially in the automotive area, such as exterior automotive applications, and can replace sophisticated polypropylene compositions.

The present invention relates to a composition obtainable by blending at least components (A), (B) and (C).

Further, the present invention relates to an article, preferably a moulded article or fiber reinforced composite, more preferably an automotive article comprising the composition as described above or below.

Still further, the present invention relates to the use of the composition as described above or below for the production of articles, preferably automotive articles, more preferably exterior automotive articles.

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 for testing 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. Unless clearly indicated otherwise, use of the terms "a", "an", and the like refers to one or more.

Mixed plastics is defined by the presence of low amounts of compounds usually not found in virgin polypropylene blends such as polystyrenes, polyamides, polyesters, wood, paper, limonene, aldehydes, ketones, fatty acids, metals, and/or long term decomposition products of stabilizers. Virgin polypropylene blends denote blends as directly originating from the production process without intermediate use.

As a matter of definition "mixed plastics" can be equated with detectable amounts of polystyrene and/or polyamide-<NUM> and/or limonene and/or fatty acids.

Mixed plastics thereby can originate from both post-consumer waste and industrial waste, as opposed to virgin polymers. Post-consumer waste refers to objects having completed at least a first use cycle (or life cycle), i.e. having already served their first purpose. In contrast to that, industrial waste refers to manufacturing scrap, respectively conversion scrap, which does not normally reach a consumer.

It will be understood by those skilled in the art that a soluble fraction (SF) as obtained by CRYSTEX QC analysis having an intrinsic viscosity (iV(SF)) in the range from <NUM> to <NUM> dl/g is typically found in material from recycling streams. In a preferred aspect of the invention the soluble fraction (SF) as obtained by CRYSTEX QC analysis has an intrinsic viscosity (iV(SF)) in the range from <NUM> to <NUM> dl/g.

A polymer blend is a mixture of two or more polymeric components. In general, the blend can be prepared by mixing the two or more polymeric components. A suitable mixing procedure known in the art is post-polymerization blending. Post-polymerization blending can be dry blending of polymeric components such as polymer powders and/or compounded polymer pellets or melt blending by melt mixing the polymeric components.

A propylene homopolymer is a polymer, which essentially consists of propylene monomer units. Due to impurities especially during commercial polymerization processes a propylene homopolymer can comprise up to <NUM> mol% comonomer units, preferably up to <NUM> mol% comonomer units and most preferably up to <NUM> mol% comonomer units.

"Polypropylene-polyethylene blend" refers to a composition containing both polypropylene and polyethylene including also polypropylene copolymers as well as polyethylene copolymers. As a direct determination of the polypropylene content and polyethylene content is not possible, the weight ratio polypropylene (A-<NUM>) to polyethylene (A-<NUM>) of <NUM>: <NUM> to <NUM>:<NUM> denotes the equivalent ratio as determined from calibration by iPP and HDPE and determination by IR spectroscopy.

A polypropylene means a polymer being composed of units derived from propylene in an amount of more than <NUM> mol-%.

A polyethylene means a polymer being composed of units derived from ethylene in an amount of more than <NUM> mol-%.

The term "XCS" refers to the xylene cold soluble fraction (XCS wt. -%) determined at <NUM> according to ISO <NUM>. The term "XCI" refers to the xylene cold insoluble fraction (XCI wt. -%) determined at <NUM> according to ISO <NUM>.

Reactor blend is a blend originating from the production in two or more reactors coupled in series or in a reactor having two or more reaction compartments. A reactor blend may alternatively result from blending in solution. A reactor blend stands in contrast to a compound as produced by melt extrusion.

If not indicated otherwise "%" refers to weight-% (wt.

In a first aspect, the present invention relates to a composition obtainable by blending at least components (A), (B) and (C).

The composition suitable for automotive application according to the present invention is particularly suitable for molding of articles, such as injection moulding of articles, or fiber reinforced composites to be used on the exterior of vehicles.

The composition according to the present invention has one or more of the following characteristics:
The composition has a melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.

The composition can be characterized by CRYSTEX QC analysis. In the CRYSTEX QC analysis a crystalline fraction (CF) and a soluble fraction (SF) are obtained which can be quantified and analyzed in regard of the monomer and comonomer content as well as the intrinsic viscosity (iV).

The composition preferably shows one or all of the following properties in the CRYSTEX QC analysis:.

Said crystalline fraction (CF) preferably has one or more, preferably all of the following properties:.

Said soluble fraction (SF) preferably has one or more, preferably all of the following properties:.

The composition preferably comprises units derived from ethylene in an amount of from <NUM> to <NUM> wt. -%, more preferably from <NUM> to <NUM> wt. -%, still more preferably from <NUM> to <NUM> wt.

Further, the composition preferably has an intrinsic viscosity (iV(Comp)) of <NUM> to <NUM> dl/g, more preferably of <NUM> to <NUM> dl/g, still more preferably of <NUM> to <NUM> dl/g.

The composition according to the invention preferably shows a superior balance of properties in regard of impact properties, flowability, as can be seen from the melt flow rate described above, and especially mechanical properties, such as in in regard of the tensile modulus or other tensile properties.

The composition preferably has a tensile modulus of from <NUM> MPa to <NUM> MPa, more preferably from <NUM> MPa to <NUM> MPa.

Further, the composition preferably has a tensile strain at tensile strength of from <NUM> to <NUM> %, more preferably from <NUM> to <NUM> %,.

Still further, the composition preferably has a tensile strain at yield of from <NUM> to <NUM> %, more preferably from <NUM> to <NUM> %.

Further, the composition preferably has a tensile strength of from <NUM> to <NUM> MPa, more preferably from <NUM> to <NUM> MPa.

Still further, the composition preferably has a tensile stress at break of from <NUM> to <NUM> MPa, more preferably from <NUM> to <NUM> MPa,.

Additionally, the composition preferably has a nominal tensile strain at break of from <NUM> to <NUM> %, more preferably from <NUM> to <NUM> %.

In regard of impact properties, the composition preferably has a Charpy Notched Impact Strength at <NUM> (CNIS at <NUM>) of from <NUM> kJ/m<NUM> to <NUM> kJ/m<NUM>, preferably from <NUM> kJ/m<NUM> to <NUM> kJ/m<NUM>.

Further, the composition preferably has a Charpy Notched Impact Strength at -<NUM> (CNIS at -<NUM>) of from <NUM> kJ/m<NUM> to <NUM> kJ/m<NUM>, preferably from <NUM> kJ/m<NUM> to <NUM> kJ/m<NUM>.

The composition of the invention mandatorily comprises components (A), (B) and (C) as described above or below in the accordantly described amounts.

The composition can optionally comprise additional polymeric components so that the composition may be obtainable by blending components (A), (B), (C) and one or more of the following component (D).

In one embodiment, the composition is obtainable by blending components (A), (B) and (C), with (D) not being present,.

whereby all percentages refer to the total composition.

In another embodiment, the composition is obtainable by blending components (A), (B), (C) and (D),.

The mixed-plastics polypropylene blend (A) originates from post-consumer waste and/or industrial waste.

The mixed-plastics polypropylene blend (A) is suitably characterized by CRYSTEX QC analysis. In the CRYSTEX QC analysis, a crystalline fraction (CF) and a soluble fraction (SF) are obtained which can be quantified and analyzed in regard of the monomer and comonomer content as well as the intrinsic viscosity (iV).

The mixed-plastics polypropylene blend (A) shows the following properties in the CRYSTEX QC analysis:.

Said crystalline fraction (CF) has one or more, preferably all of the following properties:.

Said soluble fraction (SF) has one or more, preferably all of the following properties:.

Preferably, the mixed-plastics polypropylene blend (A) comprises polypropylene and polyethylene.

The weight ratio of polypropylene to polyethylene is preferably from <NUM>:<NUM> to <NUM>:<NUM>.

The mixed-plastics polypropylene blend (A) preferably comprises units derived from propylene in an amount of more than <NUM> mol-%.

The mixed-plastics polypropylene blend (A) preferably comprises units derived from ethylene in an amount of from <NUM> to <NUM> wt. -%, more preferably from <NUM> to <NUM> wt. -%, still more preferably from <NUM> to <NUM> wt.

Further, the mixed-plastics polypropylene blend (A) preferably has one or more, preferably all of the following properties:.

The mixed-plastics polypropylene blend according to the present invention is preferably present in the form of pellets. Pelletization contributes to the low amounts of volatile substances.

The first propylene homopolymer (B) has a very high melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.

Preferably, the first propylene homopolymer (B) has a melting temperature of from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

Further, the first propylene homopolymer (B) preferably has a narrow polydispersity index, measured as ratio of weight average molecular weight to number average molecular weight, Mw/Mn, of less than <NUM>, such as from <NUM> to <NUM>, more preferably from <NUM> to <NUM>.

Still further, the first propylene homopolymer (B) has a tensile modulus of from <NUM> to <NUM> MPa, preferably <NUM> to <NUM> MPa, more preferably <NUM> to <NUM> MPa.

The presence of the first propylene homopolymer (B) ensures the high melt flow rate of the final composition.

Such propylene homopolymers are commercially available.

The second propylene homopolymer (C) has a lower melt flow rate (<NUM>, <NUM>, ISO <NUM>) than the first propylene homopolymer (B) of from <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.

The second propylene homopolymer (C) has a tensile modulus of from <NUM> to <NUM> MPa, preferably <NUM> to <NUM> MPa, more preferably <NUM> to <NUM> MPa.

Further, the second propylene homopolymer (C) preferably has one or more, preferably all of the following properties:.

Thereby, the tensile properties are all measured according to ISO <NUM>-<NUM> at <NUM>/min, the HDT is measured according to ISO <NUM>-<NUM> at <NUM> MPa and the CNIS is measured according to ISO <NUM>/1eA.

Additives are commonly used in the composition according to the present invention. Preferably, the additives are selected from one or more of antioxidant(s), UV stabilizer(s), slip agent(s), nucleating agent(s), pigment(s), lubricant(s), masterbatch polymer(s) and/or antifogging agents.

Additives are usually present in the composition in an amount of from <NUM> to <NUM> wt. -%, preferably in an amount of <NUM> to <NUM> wt. -%, based on the total composition.

The optional third propylene homopolymer (D) preferably has the lowest melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the three propylene homopolymers (B), (C) and (D) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.

The optional third propylene homopolymer (D) preferably has a higher tensile modulus than the the second propylene homopolymer (C). The tensile modulus of the optional third propylene homopolymer (D) is preferably from <NUM> to <NUM> MPa, preferably <NUM> to <NUM> MPa, more preferably <NUM> to <NUM> MPa, measured according to ISO <NUM>-<NUM> at <NUM>/min.

Further, the optional third propylene homopolymer (D) preferably has one or more, preferably all of the following properties:.

The optional third propylene homopolymer (D) preferably is nucleated, more preferably is nucleated by poly(vinylcyclohexane) as described e.g. in <CIT>.

Such propylene homopolymers are usually added for further improving the mechanical properties of the composition.

In another aspect, the present invention relates to an article, preferably a moulded article or fiber reinforced composite, more preferably an automotive article comprising the composition comprising the composition as described above or below.

The article is preferably used on the exterior of vehicles.

In one embodiment the composition of the article can comprise fiber, such as glass fibers. In the case fibers are present in the composition of the article, the amount of fibers is in the range of from <NUM> to <NUM> wt%, based on the composition of the article.

In yet another aspect the present invention relates to the use of the composition as described above or below for the production of articles, preferably automotive articles, more preferably exterior automotive articles.

In one embodiment the composition used for the production of articles can comprise fibers, such as glass fibers. In the case fibers are present in the composition of the article, the amount of fibers is in the range of from <NUM> to <NUM> wt%, based on the composition of the article.

The following Examples are included to demonstrate certain aspects and embodiments of the invention as described in the claims. It should be appreciated by those of skill in the art, however, that the following description is illustrative only and should not be taken in any way as a restriction of the invention.

The crystalline (CF) and soluble fractions (SF) of the polypropylene (PP) compositions as well as the comonomer content and intrinsic viscosities of the respective fractions were analyzed by use of the CRYSTEX instrument, Polymer Char (Valencia, Spain). Details of the technique and the method can be found in literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer & Markus Gahleitner (<NUM>) 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, <NUM>:<NUM>, <NUM>-<NUM>).

The crystalline and amorphous fractions are separated through temperature cycles of dissolution at <NUM>, crystallization at <NUM> and re-dissolution in <NUM>,<NUM>,<NUM>-trichlorobenzene at <NUM>. Quantification of SF and CF and determination of ethylene content (C2) are achieved by means of an integrated infrared detector (IR4) and for the determination of the intrinsic viscosity (iV) an online <NUM>-capillary viscometer is used.

The IR4 detector is a multiple wavelength detector measuring IR absorbance at two different bands (CH<NUM> stretching vibration (centred at app. <NUM>-<NUM>) and the CH stretching vibration (<NUM>-<NUM>-<NUM>) that are serving for the determination of the concentration and the Ethylene content in Ethylene-Propylene copolymers. The IR4 detector is calibrated with series of <NUM> EP copolymers with known Ethylene content in the range of <NUM> wt. -% to <NUM> wt. -% (determined by <NUM>C-NMR) and each at various concentrations, in the range of <NUM> and <NUM>/ml. To encounter for both features, concentration and ethylene content at the same time for various polymer concentrations expected during Crystex analyses the following calibration equations were applied: <MAT> <MAT>.

The constants a to e for equation <NUM> and a to f for equation <NUM> were determined by using least square regression analysis.

The CH<NUM>/1000C is converted to the ethylene content in wt. -% using following relationship: <MAT>.

Amounts of Soluble Fraction (SF) and Crystalline Fraction (CF) are correlated through the XS calibration to the "Xylene Cold Soluble" (XCS) quantity and respectively Xylene Cold Insoluble (XCI) fractions, determined according to standard gravimetric method as per ISO16152. XS calibration is achieved by testing various EP copolymers with XS content in the range <NUM>-<NUM> wt. The determined XS calibration is linear: <MAT>.

Intrinsic viscosity (iV) of the parent EP copolymer and its soluble and crystalline fractions are determined with a use of an online <NUM>-capillary viscometer and are correlated to corresponding iV's determined by standard method in decalin according to ISO <NUM>-<NUM>. Calibration is achieved with various EP PP copolymers with iV = <NUM>-<NUM> dL/g. The determined calibration curve is linear: <MAT>.

The samples to be analyzed are weighed out in concentrations of <NUM>/ml to <NUM>/ml. To avoid injecting possible gels and/or polymers which do not dissolve in TCB at <NUM>, like PET and PA, the weighed out sample was packed into a stainless steel mesh MW <NUM>,<NUM>/D <NUM>,05mmm.

After automated filling of the vial with <NUM>,<NUM>,<NUM>-TCB containing <NUM>/l <NUM>,<NUM>-tert-butyl-<NUM>-methylphenol (BHT) as antioxidant, the sample is dissolved at <NUM> until complete dissolution is achieved, usually for <NUM>, with constant stirring of 400rpm. To avoid sample degradation, the polymer solution is blanketed with the N2 atmosphere during dissolution.

A defined volume of the sample solution is injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part is taking place. This process is repeated two times. During the first injection the whole sample is measured at high temperature, determining the iV [dl/g] and the C2 [wt. -%] of the PP composition. During the second injection the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) with the crystallization cycle are measured (wt. -% C2, iV).

Xylene cold soluble fraction (XCS) was determined at <NUM> according ISO <NUM>; first edition; <NUM>-<NUM>-<NUM>. The part which remains insoluble is the xylene cold insoluble (XCI) fraction.

Intrinsic viscosity was measured according to DIN ISO <NUM>/<NUM>, October <NUM> (in Decalin at <NUM>).

was determined according to ISO <NUM>-<NUM> eA at +<NUM> and at -<NUM> on injection molded specimens of <NUM> x <NUM> x <NUM><NUM> prepared according to EN ISO <NUM>-<NUM>. The measurement was done after <NUM> conditioning time at <NUM> of the specimen.

The tensile properties (tensile modulus, tensile strain at break, tensile strength, tensile strain at tensile strength, tensile strain at yield, tensile stress at break) were measured according to ISO <NUM>-<NUM> (cross head speed = <NUM>/min; test speed <NUM>/min at <NUM>) using injection molded specimens 1B prepared as described in EN ISO <NUM>-<NUM> (dog bone shape, <NUM> thickness). The measurement was done after <NUM> conditioning time at <NUM> of the specimen.

Quantitative infrared (IR) spectroscopy was used to quantify the ethylene content of the poly(ethylene-co-propene) copolymers through calibration to a primary method. Calibration was facilitated through the use of a set of in-house non-commercial calibration standards of known ethylene contents determined by quantitative <NUM>C solution-state nuclear magnetic resonance (NMR) spectroscopy. The calibration procedure was undertaken in the conventional manner well documented in the literature. The calibration set consisted of <NUM> calibration standards with ethylene contents ranging <NUM>-<NUM> wt. % produced at either pilot or full scale under a variety of conditions. The calibration set was selected to reflect the typical variety of copolymers encountered by the final quantitative IR spectroscopy method. Quantitative IR spectra were recorded in the solid-state using a Bruker Vertex <NUM> FTIR spectrometer. Spectra were recorded on 25x25 mm square films of <NUM> thickness prepared by compression moulding at <NUM> - <NUM> and <NUM>-<NUM> MPa. For samples with very high ethylene contents (><NUM> mol%) <NUM> thick films were used. Standard transmission FTIR spectroscopy was employed using a spectral range of <NUM>-<NUM>-<NUM>, an aperture of <NUM>, a spectral resolution of <NUM>-<NUM>, <NUM> background scans, <NUM> spectrum scans, an interferogram zero filling factor of <NUM> and Blackmann-Harris <NUM>-term apodisation. Quantitative analysis was undertaken using the total area of the CH<NUM> rocking deformations at <NUM> and <NUM>-<NUM> (AQ) corresponding to (CH<NUM>)><NUM> structural units (integration method G, limits <NUM> and <NUM>-<NUM>). The quantitative band was normalised to the area of the CH band at <NUM>-<NUM> (AR) corresponding to CH structural units (integration method G, limits <NUM>, <NUM>-<NUM>). The ethylene content in units of weight percent was then predicted from the normalised absorption (AQ / AR) using a quadratic calibration curve. The calibration curve having previously been constructed by ordinary least squares (OLS) regression of the normalised absorptions and primary comonomer contents measured on the calibration set.

Quantitative <NUM>C{<NUM>H} NMR spectra were recorded in the solution-state using a Bruker Avance III <NUM> NMR spectrometer operating at <NUM> and <NUM> for <NUM>H and <NUM>C respectively. All spectra were recorded using a <NUM>C optimised <NUM> extended temperature probehead at <NUM> using nitrogen gas for all pneumatics. Approximately <NUM> of material was dissolved in <NUM> of <NUM>,<NUM>-tetrachloroethane-d<NUM> (TCE-d<NUM>) along with chromium (III) acetylacetonate (Cr(acac)<NUM>) resulting in a <NUM> solution of relaxation agent in solvent (<NPL>).

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 <NUM> hour. Upon insertion into the magnet the tube was spun at <NUM>. 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, <NUM> recycle delay and a bi-level WALTZ16 decoupling scheme (<NPL>, and in <NPL>). A total of <NUM> (<NUM>) transients were acquired per spectra. Quantitative <NUM>C{<NUM>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 <NUM> 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 (<NPL>) 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 ) The comonomer fraction was quantified using the method of Wang et. (Wang, W-J. , Macromolecules <NUM> (<NUM>), <NUM>) through integration of multiple signals across the whole spectral region in the <NUM>C{<NUM>H} spectra. For systems with very low ethylene content where only isolated ethylene in PPEPP sequences were observed the method of Wang et. was modified reducing the influence of integration of sites that are no longer present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content to E = <NUM>( Sββ + Sβγ + Sβδ + <NUM>( Sαβ + Sαγ)) Through the use of this set of sites the corresponding integral equation becomes E = <NUM>( IH +IG + <NUM>( IC + ID )) using the same notation used in the article of Wang et. (Wang, W-J. , Macromolecules <NUM> (<NUM>), <NUM>). The mole percent comonomer incorporation was calculated from the mole fraction: E [mol%] = <NUM> * fE. The weight percent comonomer incorporation was calculated from the mole fraction: E [wt. %] = <NUM> * ( fE * <NUM> ) / ( (fE * <NUM>) + ((<NUM>-fE) * <NUM>) ).

Contents were determined using a film thickness method using the intensity of the quantitative band I(q) and the thickness of the pressed film T using the following relationship:
[ I(q) / T ]m + c = C where m and c are the coefficients determined from the calibration curve constructed using the comonomer contents obtained from <NUM>C-NMR spectroscopy.

Comonomer content was measured in a known manner based on Fourier transform infrared spectroscopy (FTIR) calibrated with <NUM>C-NMR, using Nicolet Magna <NUM> IR spectrometer together with Nicolet Omnic FTIR software. Films having a thickness of about <NUM> were compression molded from the samples. Similar films were made from calibration samples having a known content of the comonomer. The comonomer content was determined from the spectrum from the wave number range of from <NUM> to <NUM>-<NUM>. The absorbance was measured as the height of the peak by selecting the so-called short or long base line or both. The short base line was drawn in about <NUM> - <NUM>-<NUM> through the minimum points and the long base line about between <NUM> and <NUM>-<NUM>. Calibrations needed to be done specifically for each base line type. Also, the comonomer content of the unknown sample was within the range of the comonomer contents of the calibration samples.

Melt flow rates were measured with a load of <NUM> (MFR<NUM>) at <NUM> (polypropylene based materials) or at <NUM> (polyethylene based materials). The melt flow rate is that quantity of polymer in grams which the test apparatus standardized to ISO <NUM> extrudes within <NUM> minutes at a temperature of <NUM> (or <NUM>) under a load of <NUM>.

Density was measured according to ISO <NUM>-<NUM>. Sample preparation was done by compression molding in accordance with ISO <NUM>-<NUM>:<NUM>.

The characterization of polymer melts by dynamic shear measurements complies with ISO standards <NUM>-<NUM> and <NUM>-<NUM>. The measurements were performed on an Anton Paar MCR501 stress controlled rotational rheometer, equipped with a <NUM> parallel plate geometry. Measurements were undertaken on compression moulded plates using nitrogen atmosphere and setting a strain within the linear viscoelastic regime. The oscillatory shear tests were done at <NUM> applying a frequency range between <NUM> and <NUM> rad/s and setting a gap of <NUM>.

In a dynamic shear experiment the probe is subjected to a homogeneous deformation at a sinusoidal varying shear strain or shear stress (strain and stress controlled mode, respectively). On a controlled strain experiment, the probe is subjected to a sinusoidal strain that can be expressed by <MAT>.

If the applied strain is within the linear viscoelastic regime, the resulting sinusoidal stress response can be given by <MAT> where σ<NUM>, and γ<NUM> are the stress and strain amplitudes, respectively; ω is the angular frequency; δ is the phase shift (loss angle between applied strain and stress response); t is the time. Dynamic test results are typically expressed by means of several different rheological functions, namely the shear storage modulus, G', the shear loss modulus, G", the complex shear modulus, G*, the complex shear viscosity, η*, the dynamic shear viscosity, η', the out-of-phase component of the complex shear viscosity, η" and the loss tangent, tan η, which can be expressed as follows: <MAT> <MAT> <MAT> <MAT> <MAT> <MAT>.

The determination of so-called Shear Thinning Index, which correlates with MWD and is independent of Mw, is done as described in equation <NUM>.

For example, the SHI(<NUM>/<NUM>) is defined by the value of the complex viscosity, in Pa s, determined for a value of G* equal to <NUM> kPa, divided by the value of the complex viscosity, in Pa s, determined for a value of G* equal to <NUM> kPa.

The values of storage modulus (G'), loss modulus (G"), complex modulus (G*) and complex viscosity (η*) were obtained as a function of frequency (ω).

Thereby, e.g. η*300rad/s (eta*300rad/s) is used as abbreviation for the complex viscosity at the frequency of <NUM> rad/s and η*<NUM>. 05rad/s (eta*<NUM>. 05rad/s) is used as abbreviation for the complex viscosity at the frequency of <NUM> rad/s.

The loss tangent tan (delta) is defined as the ratio of the loss modulus (G") and the storage modulus (G') at a given frequency. Thereby, e.g. tan<NUM> is used as abbreviation for the ratio of the loss modulus (G") and the storage modulus (G') at <NUM> rad/s and tan<NUM> is used as abbreviation for the ratio of the loss modulus (G") and the storage modulus (G') at <NUM> rad/s. The elasticity balance tan<NUM>/tan<NUM> is defined as the ratio of the loss tangent tan<NUM> and the loss tangent tan<NUM>.

Besides the above mentioned rheological functions one can also determine other rheological parameters such as the so-called elasticity index EI(x). The elasticity index Ei(x) is the value of the storage modulus, G' determined for a value of the loss modulus, G" of x kPa and can be described by equation <NUM>.

For example, the EI(5kPa) is the defined by the value of the storage modulus G', determined for a value of G" equal to <NUM> kPa.

The polydispersity index, PI, is defined by equation <NUM>. <MAT> where ωCOP is the cross-over angular frequency, determined as the angular frequency for which the storage modulus, G', equals the loss modulus, G".

The values are determined by means of a single point interpolation procedure, as defined by Rheoplus software. In situations for which a given G* value is not experimentally reached, the value is determined by means of an extrapolation, using the same procedure as before. In both cases (interpolation or extrapolation), the option from Rheoplus "Interpolate y-values to x-valuesfrom parameter" and the "logarithmic interpolation type" were applied.

The HDT was determined on injection molded test specimens of <NUM> × <NUM> × <NUM><NUM> prepared according to ISO <NUM>-<NUM> and stored at +<NUM> for at least <NUM> hours prior to measurement. The test was performed on flatwise supported specimens according to ISO <NUM>, condition B, with a nominal surface stress of <NUM> MPa.

Table <NUM> shows the properties of the polypropylene / polyethylene blends (A-<NUM>) and (A-<NUM>) suitable as mixed-plastics polypropylene blend (A). As these compositions come from a mechanical recycling process, the properties are indicated as ranges.

Table <NUM> shows the properties of the samples of blends (A-<NUM>) and (A-<NUM>), which were used for the evaluation.

As blend A-<NUM> the mixed-plastics polypropylene blend Dipolen PP is used, commercially available from mtm Plastics GmbH. Dipolen PP is a post-consumer recyclate polypropylene based material having a density (determined according to DIN EN ISO <NUM>) of <NUM>/m<NUM>, a melt flow rate (determined according to DIN EN ISO <NUM>, <NUM>/<NUM>) of <NUM>/<NUM>, a moisture content (determined via a moisture infrared analyzer, <NUM>) of less than <NUM> %, a tensile modulus (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> MPa, a yield stress (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> MPa, and a tensile strain (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> %.

As blend A-<NUM> the mixed-plastics polypropylene blend Purpolen PP is used, commercially available from mtm Plastics GmbH. Purpolen PP is a post-consumer recyclate polypropylene based material having a density (determined according to DIN EN ISO <NUM>) of <NUM>/m<NUM>, a melt flow rate (determined according to DIN EN ISO <NUM>, <NUM>/<NUM>) of <NUM>/<NUM>, a moisture content (determined via a moisture infrared analyzer, <NUM>) of less than <NUM> %, a tensile modulus (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> MPa, a yield stress (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> MPa, and a tensile strain (determined according to DIN EN ISO <NUM>, <NUM>/min) of more than <NUM> %.

PP-Homo <NUM> was propylene homopolymer HL708FB with an MFR<NUM> (<NUM>, <NUM>, ISO1133) of <NUM>/<NUM> and a Tm (DSC, ISO <NUM>-<NUM>) of <NUM>, commercially available from Borealis AG, Austria and represents the first propylene homopolymer (B).

PP-Homo <NUM> was propylene homopolymer HK060AE with an MFR<NUM> (<NUM>, <NUM>, ISO1133) of <NUM>/<NUM> and a Tm (DSC, ISO <NUM>-<NUM>) of <NUM>, commercially available from Borealis AG, Austria and represents the second propylene homopolymer (C). Further properties are disclosed in Table <NUM> below in example CE1.

PP-Homo <NUM> was propylene homopolymer HF955MO with an MFR<NUM> (<NUM>, <NUM>, ISO1133) of <NUM>/<NUM> and a tensile modulus of <NUM> MPa (ISO <NUM>-<NUM>, <NUM>/min), commercially available from Borealis AG, Austria and represents the third propylene homopolymer (D).

Additives is an antioxidant one-pack of Pentaerythrityl-tetrakis(<NUM>-(<NUM>',<NUM>'-di-tert. butyl-<NUM>-hydroxyphenyl)-propionate and Tris (<NUM>,<NUM>-di-t-butylphenyl) phosphite in a weight ratio of <NUM>:<NUM>.

The HC001A having a density of <NUM>/m<NUM>, an MFR<NUM> (determined according to ISO <NUM>, <NUM>, <NUM>) of <NUM>/<NUM>, and a crystallization temperature Tc of <NUM> was used as a homo-PP based carrier of the additives.

Table <NUM> shows the compositions of the examples.

Table <NUM> shows the properties of the examples.

The inventive examples show composition with around <NUM> wt% of blends from household waste with a high melt flow rate of around <NUM>/<NUM> and good mechanical properties. The inventive compostions show a higher impact strength than the comparative example CE1.

The addition of PP Homo <NUM> in examples IE1, IE5 and IE6 further improve the tensile properties without impairing the high melt flow rates.

Claim 1:
A composition obtainable by blending at least components (A), (B) and (C)
(A) <NUM> wt.-% to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-%, more preferably <NUM> to <NUM> wt.-% of a mixed-plastics polypropylene blend, which originates from post-consumer waste and/or industrial waste;
(B) <NUM> wt.-% to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-%, more preferably <NUM> to <NUM> wt.-% of a first propylene homopolymer; and
(C) <NUM> wt.-% to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-%, more preferably <NUM> to <NUM> wt.-% of a second propylene homopolymer,
whereby all percentages refer to the total composition, and whereby
the mixed-plastics polypropylene blend (A) has
- a crystalline fraction (CF) content determined according to CRYSTEX QC analysis in the range from <NUM> to <NUM> wt.-%, preferably in the range from <NUM> to <NUM> wt.-%, and
- a soluble fraction (SF) content determined according to CRYSTEX QC analysis in the range from <NUM> to <NUM> wt.-%, preferably in the range from <NUM> to <NUM> wt.-%, whereby
- said crystalline fraction (CF) has an ethylene content (C2(CF)), as determined by FT-IR spectroscopy calibrated by quantitative <NUM>C-NMR spectroscopy, in the range from <NUM> to <NUM> wt.-%, preferably in the range from <NUM> to <NUM> wt.-%; and
- said soluble fraction (SF) has an intrinsic viscosity (iV(SF)) in the range from <NUM> to below <NUM> dl/g, preferably in the range from <NUM> to <NUM> dl/g, more preferably in the range from <NUM> to <NUM> dl/g;
the first propylene homopolymer (B) has
- a melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>; and
the second propylene homopolymer (C) has
- a melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>; and
- a tensile modulus of <NUM> to <NUM> MPa, preferably <NUM> to <NUM> MPa, more preferably <NUM> to <NUM> MPa, and
the composition has
- a melt flow rate MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.