Patent Description:
Mixtures of polypropylene and polyethylene are characterized by limited miscibility. When processing such mixtures into final products, the mechanical and optical properties limit the possible applications to non-demanding ultra-low cost applications such as park benches or geotextile reinforcements. Blend morphology is one of the decisive hurdles towards valuable applications which is particularly visible in the field of recycled materials. Very common recycling streams contain polyethylene and polypropylene next to a number of byproducts. Separation can be carried out using density separation in water and then further separation based on fluorescence, near infrared absorption or Raman fluorescence. However, it is commonly quite difficult to obtain either pure recycled polypropylene or pure recycled polyethylene. Generally, recycled quantities of polypropylene on the market are mixtures of both polypropylene (PP) and polyethylene (PE), this is especially true for post-consumer waste streams. Moreover, recycled polyolefin materials are often cross-contaminated with non-polyolefin materials such as polyethylene terephthalate, polyamide, polystyrene or non-polymeric substances like wood, paper, glass or aluminum further limiting morphology. The use of various compatibilizers is known in the art. <NPL> described the use of diblock, tetrablock, and hexablock copolymers (BCPs) for compatibilization of isotactic polypropylene and HDPE. The authors have also described that the use of ethylene propylene rubber (EPR) and ethylene propylene diene monomer (EPDM) rubber result in phase separation problems and, when used in higher amounts, compromises the tensile strength. Olefin block copolymers (OBCs) are reported to be good compatibilizers for mixtures of PE and iPP such as described by <NPL>. However, the broad use of OBCs is limited due to the challenging and costly production method. Another group of compatibilizers are ethylene octene elastomers (EO rubbers) which are also rather expensive and may deteriorate stiffness. The use of heterophasic copolymers and heterophasic random copolymers for upgrading a recycled polyolefin stream has been described in literature mostly dealing with stiffness and impact properties. <CIT> teaches the use of heterophasic polyolefin compositions having a flexural modulus of lower than <NUM> MPa within a broad melt flow rate range of <NUM> to <NUM>/<NUM> and broad elongation at break range of <NUM> to <NUM>%. Inter alia, a low MFR (<NUM>/<NUM>) heterophasic polyolefin "HC2" including two fractions of propylene copolymers, a first propylene random copolymer and a second essentially linear ethylene/propylene copolymer being insoluble in xylene as well as an ethylene propylene rubber with an intrinsic viscosity of <NUM> dl/g has been exemplified for upgrading recyclates having a PE/PP ratio of about <NUM>. Compatibilizer "HC2" was further subjected to visbreaking yielding a MFR of <NUM>/<NUM> and used for recyclates having a PE/PP ratio of about <NUM>. It turned out that the elongation at break values of the upgraded compositions are only satisfactory at undesirable high amounts of heterophasic polyolefin.

Thus, there is a deeply felt need in the art for further compatibilizers for PP/PE mixtures for improving mechanical performances, i.e. improving the balance between flowability (MFR), stiffness (as measured by Tensile modulus ISO <NUM>-<NUM>), impact strength (Charpy Notched Impact Strength ISO <NUM>-<NUM> eA at +<NUM> and at -<NUM>), and particularly elongation at break (ISO <NUM>-<NUM>) as well as room temperature puncture (<NUM>) resistance and especially cold puncture resistance (at <NUM> and -<NUM>) at low amounts of compatibilizer.

The present invention is concerned with a heterophasic copolymer according to claim <NUM> for compatibilization of a polypropylene/polyethylene blend (A) said polypropylene/polyethylene blend (A) having one or more of the following properties:.

The present invention is further concerned with the use of the heterophasic copolymer as a compatibilizer according to claim <NUM>. The present invention further concerns a process for upgrading a polypropylene-polyethylene blend (A) comprising (A-<NUM>) polypropylene and (A-<NUM>) polyethylene whereby the weight ratio of polypropylene (A-<NUM>) to polyethylene (A-<NUM>) is <NUM>:<NUM> to <NUM>:<NUM> as claimed in claim <NUM>. The present invention also concern a polypropylene-polyethylene composition as set forth in claim <NUM> as well as an article comprising this polypropylene-polyethylene composition as set forth in claim <NUM>.

The present invention provides the use of a compatibilizer (B) being a heterophasic copolymer comprising a matrix phase and an elastomer phase dispersed therein, whereby the matrix phase includes a random polypropylene copolymer, and whereby the heterophasic copolymer has.

for upgradinga polypropylene-polyethylene blend (A) comprising.

The present invention further provides a process for upgrading a polypropylene-polyethylene blend (A) comprising.

In a further aspect, the present invention provides a polypropylene-polyethylene composition obtainable by blending.

In yet a further aspect, the present invention provides a heterophasic copolymer according to claim <NUM> for compatibilization of polypropylene/polyethylene blends comprising a matrix phase and an elastomer phase dispersed therein, whereby the matrix phase includes a random polypropylene copolymer and, whereby the heterophasic copolymer has.

the xylene cold soluble content (XCS) having an intrinsic viscosity (measured in decalin according to DIN ISO <NUM>/<NUM> at <NUM>) of <NUM> dl/g to less than <NUM> dl/g, preferably <NUM> to <NUM> dl/g, most preferably <NUM> to <NUM> dl/g.

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. A propylene homopolymer-random copolymer matrix phase of the compatibilizer (B), i.e. of the heterophasic copolymer according to the present invention denotes a matrix phase being composed of a propylene homopolymer mixed with a random polypropylene copolymer. The presence of two polymers, i.e. a first polypropylene homopolymer and a second polypropylene random copolymer may be detected by the presence of two melting points within the ranges as specified such as by two recognizable peaks or a peak and a shoulder by the differential scanning calorimetry (DSC). "Upgrading" means improving one or more properties such as elongation at break, Charpy notched impact or particle morphology of the reactant blend such that the resulting composition, i.e. the combination of the reactant blend and the compatibilizer, shows one or more properties superior to the reactant blend. Dispersed phase particle morphology describes the size distribution of the particles of the dispersed phase as observable by microscopy. "Upgrading" of the dispersed phase particle morphology means that the morphology of the dispersed phase as observed by microscopy and optionally analyzed by image analysis is refined.

For the purpose of the present invention.

For the purposes of the present description, the term "recycled waste" or "recycled material" is used to indicate a material recovered 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; while industrial waste refers to manufacturing scrap, which does not normally reach a consumer. The term "virgin" denotes the newly produced materials and/or objects prior to their first use, which have not already been recycled. Virgin materials and recycled materials easily can be differentiated based on absence or presence of contaminants such as limonene and/or fatty acids and/or paper and/or wood. Polypropylene-polyethylene blends also can be differentiated with respect to their origin by presence of polystyrene and/or polyamide. Residual content denotes a content above the detection limit. Many different kinds of polyethylene or polypropylene can be present in "recycled material". The ratio polypropylene (A-<NUM>) versus polyethylene plus polyethylene copolymer (A-<NUM>) is determined experimentally by using isotactic polypropylene (iPP) and high density polyethylene (HDPE) for calibration. 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 procedures 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 random copolymer is a copolymer of propylene monomer units and comonomer units in which the comonomer units are distributed randomly over the polypropylene chain. A "compatibilizer" is a substance in polymer chemistry, which is added to a blend of polymers with limited miscibility in order to increase their stability. "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. The term "elastomer" denotes a natural or synthetic polymer having elastic properties. The term "XCS" refers to the xylene cold soluble content (XCS wt. -%) determined at <NUM> according to ISO <NUM>. The term "XCI" refers to the xylene cold insoluble content (XCI wt. -%) determined at <NUM> according to ISO <NUM>. If not indicated otherwise "%" refers to weight-%. Presence of a heterophasic nature can be easily determined by the number of glass transition points. 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 alternatively may result from blending in solution. A reactor blend stands in contrast to a compound as produced by melt extrusion.

The compatibilizer according to the present invention is a heterophasic copolymer comprising a matrix phase and an elastomer phase dispersed therein, whereby the matrix phase includes a random polypropylene copolymer and also a polypropylene homopolymer. The skilled person will instantly recognize presence of a polypropylene homopolymer, which easily can be detected by differential scanning calorimetry, by e.g. melting peak analysis. In other words, the presence of at least one melting point Tm1 in the range of <NUM> to <NUM> indicates the presence of a polypropylene homopolymer. Usually heterophasic copolymers include either a polypropylene homopolymer matrix (commonly denoted HECO) or they include a random polypropylene copolymer matrix (commonly denoted RAHECO), whereby such matrix may also be composed of two random polypropylene copolymers differing as to their molecular weight distribution and/or their comonomer content. The heterophasic copolymer according to the present invention has a melt flow rate MFR<NUM> (<NUM>, ISO1133) of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, most preferably <NUM> to <NUM>/<NUM>. The heterophasic copolymer according to the present invention further has to have at least one melting point Tm1 in the range of <NUM> to <NUM>. As explained above, such melting point(s) signal(s) the presence of a homopolymer. Optionally a second melting point Tm2 in the range of <NUM> to <NUM> originating from the random polypropylene copolymer is present. It is possible that the melting point of the random polypropylene copolymer within a temperature range of <NUM> to <NUM> is clearly visible. However, usually this will not be the case and the melting point will appear as a shoulder in the DSC thermogram. The heterophasic copolymer according to the present invention optionally has at least a second or third melting point Tm3 in the range of <NUM> to <NUM>. Such melting point(s) originates from polyethylene. The heterophasic copolymer according to the present invention further has to have a xylene cold insoluble content (XCI) of from <NUM> to <NUM> wt. -%, preferably <NUM> to <NUM> wt. -% (ISO <NUM>, 1ed, <NUM>) and a xylene cold soluble content (XCS) of <NUM> to <NUM> wt. -%, preferably <NUM> to <NUM> wt. -% (ISO <NUM>, 1ed, <NUM>), whereby the xylene cold insoluble content (XCI) and xylene cold soluble content (XCS) add up to <NUM> wt. The amount of xylene cold soluble content should not be too high as this may deteriorate stiffness and it should also not be too low as otherwise impact and puncture resistances may not be sufficient. A skilled person will understand that both, the matrix component and the elastomer component contribute to the xylene cold soluble content. As can be seen from the experimental part, the propylene homopolymer - polypropylene random copolymer mixture, i.e. the mixture constituting the matrix component as produced in reactors one and two has a relatively high xylene cold soluble content.

The heterophasic copolymer according to the present invention further has a content of units derived from ethylene in the xylene cold insoluble content (XCI) of from <NUM> to <NUM> wt. -%, preferably from <NUM> to <NUM> wt. Moreover, the content of units derived from ethylene in the xylene cold soluble content (XCS) of the heterophasic copolymer according to the present invention is <NUM> to <NUM> wt. -%, preferably of <NUM> to <NUM> wt. In a further aspect the xylene cold soluble content (XCS) of the heterophasic copolymer according to the present invention may have an intrinsic viscosity (measured in decalin according to DIN ISO <NUM>/<NUM> at <NUM>) within a broad range of <NUM> dl/g to less than <NUM> dl/g. Preferably the intrinsic viscosity of the xylene cold soluble content (XCS) is within the range of <NUM> to <NUM> dl/g and most preferably within the range of <NUM> to <NUM> dl/g. Such IV(XCS) range is particularly beneficial for impact and puncture resistance. In yet a further preferred aspect, the xylene cold soluble content (XCS) includes units derived from ethylene and propylene only. In other words, the elastomer can only be a copolymer of propylene and ethylene.

The heterophasic copolymer according to the present invention preferably is a reactor blend of a propylene homopolymer, a random polypropylene copolymer and an ethylene propylene rubber. Thus, the heterophasic copolymer according to the present invention easily can be made in various types of polymer plants such as a Borstar® configuration (loop reactor - gas phase reactor <NUM> - gas phase reactor <NUM>), Spheripol configuration (loop reactor <NUM> - loop reactor <NUM> - gas phase reactor <NUM>), Spheripol configuration with liquid propylene as barrier gas and other common types of production plants.

The heterophasic copolymer according to the present invention, i.e. the compatibilizer (B), preferably has a tensile modulus of at least <NUM> MPa, more preferably at least <NUM> MPa and most preferably at least <NUM> MPa (measured according to ISO <NUM>-<NUM>).

In a further aspect, the heterophasic copolymer according to the present invention, i.e. the compatibilizer (B) according to the present invention, has a total content of units derived from ethylene of <NUM> to <NUM> wt.

In a specific embodiment compatibilizer (B) is made by using a Ziegler Natta catalyst. If so, the at least one melting point Tm1 in the range of <NUM> to <NUM> will be found within the range of <NUM> to <NUM>. Compatibilizers having at least one melting point Tm1 in the range of <NUM> to <NUM> are preferred due to processability and cost advantages.

The polypropylene-polyethylene blend (A) according to present invention has one or more of the following properties.

Preferably the polypropylene-polyethylene blend (A) according to present invention is a recycled material, more preferably originates from household trash.

The polypropylene-polyethylene blend (A) according to the present invention comprises.

It should be understood that polypropylene-polyethylene blend (A) may vary broadly in composition, i.e. may include polypropylene homopolymer, polypropylene copolymer, polyethylene, and 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>) is <NUM>:<NUM> to <NUM>:<NUM> is the equivalent ratio as determined from calibration by iPP and HDPE.

Conventionally the polypropylene-polyethylene blend (A) according to the present invention may have one or more of the following:.

The compatibilizer according to the present invention is used for upgrading a polypropylene-polyethylene blend (A) comprising.

According to the present invention, compatibilizer (B) is used in an amount of <NUM> to <NUM> wt. -% preferably <NUM> to <NUM> wt. -%, more preferably <NUM> to <NUM> wt. -% with respect to the final composition. Higher amounts of compatibilizer than the indicated maximum values of <NUM> wt. -%, preferably <NUM> wt. -% and most preferably <NUM> wt. -% should be avoided as otherwise the elongation at break and/or the stiffness may again be compromised.

Preferred aspects as to the polypropylene-polyethylene composition according to the present invention are described in the following.

The polypropylene-polyethylene composition according to the present invention should have a relatively high stiffness. Thus, the compatibilizer (B) preferably has a tensile modulus of at least <NUM> MPa, more preferably at least at least <NUM> MPa and most preferably as described above.

The present invention also concerns an article comprising, preferably consisting of the polypropylene-polyethylene composition as described above.

In a particularly preferred embodiment the heterophasic copolymer for compatibilization of polypropylene/polyethylene blends comprises a matrix phase and an elastomer phase dispersed therein, whereby the matrix phase includes a random polypropylene copolymer and, whereby the heterophasic copolymer has.

This heterophasic copolymer preferably has a tensile modulus of at least <NUM> MPa (measured according to ISO <NUM>-<NUM>). In a further aspect, the matrix of this heterophasic copolymer includes, preferably consists of a polypropylene homopolymer - random polypropylene copolymer mixture. In yet a further aspect, the xylene cold soluble content (XCS) of this heterophasic copolymer includes units derived from ethylene and propylene only. Moreover, it is also preferred that this heterophasic copolymer is a reactor blend of a propylene homopolymer, a random polypropylene copolymer and an ethylene propylene rubber.

In the following two particularly preferred embodiments shall be described.

The polypropylene-polyethylene composition according to a first specific and preferred embodiment of the present invention preferably has one or more of the following properties.

A good Charpy notched impact strength (1eA) (non-instrumented, ISO <NUM>-<NUM> at +<NUM>) of at least <NUM> kJ/m<NUM> easily can be achieved by use of higher amounts of compatibilizer. Intrinsic viscosity of the xylene cold soluble content IV(XCS) within the range of <NUM> to <NUM> dl/g favors Charpy notched impact strength (1eA) (non-instrumented, ISO <NUM>-<NUM> at -<NUM>) of at least <NUM> kJ/m<NUM>. Good elongation at break (ISO <NUM>-<NUM>) of at least <NUM> %, particularly <NUM>% requires limited amounts of compatibilizer and preferably an intrinsic viscosity of the xylene cold soluble content IV(XCS) of <NUM> to <NUM> dl/g, more preferably <NUM> to <NUM> dl/g. A tensile modulus of at least <NUM> MPa can only be achieved with a limited amount of compatibilizer and optionally xylene cold soluble content at the lower end of the range foreseen.

Blend (A), i.e. preferably the recyclate as contained in this first specific and preferred embodiment preferably has one or more of the following features:.

The polypropylene-polyethylene composition according to a second specific and preferred embodiment of the present invention preferably has one or more of the following properties:.

Blend (A), i.e. preferably the recyclate as contained in this second specific and preferred embodiment preferably has one or more of the following features:.

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.

To establish different calibration curves different standards, iPP and HDPE and iPP, PS and PA6 were blended. For the quantification of the content of the foreign polymers, IR spectra were recorded in the solid-state using a Bruker Vertex <NUM> FTIR spectrometer. Films were prepared with a compression-molding device at <NUM> with <NUM> - <NUM> MPa clamping force. The thickness of the films for the calibration standards for iPP and HDPE was <NUM> and for the quantification of the iPP, PS and PA <NUM><NUM>-<NUM> film thickness was used. Standard transmission FTIR spectroscopy is 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 Norton Beer strong apodization.

The absorption of the band at <NUM>-<NUM> in iPP is measured and the iPP content is quantified according to a calibration curve (absorption/thickness in cm versus iPP content in weight %).

The absorption of the band at <NUM>-<NUM> (PS) and <NUM>-<NUM> (PA6) are measured and the PS and PA6 content quantified according to the calibration curve (absorption/thickness in cm versus PS and PA content in wt. The content of polyethylene and ethylene containing copolymers is obtained by subtracting (iPP+PS+PA6) from <NUM>, taking into account the content of non-polymeric impurities as determined in the methods below. The analysis is performed as a double determination.

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.

was determined as Charpy Notched Impact Strength according to ISO <NUM>-<NUM> eA at +<NUM>, 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.

Instrumented puncture test was performed on 60x60x1 mm<NUM> injection-molded plaques at <NUM>, <NUM> and -<NUM> according to ISO6603-<NUM>:<NUM>. 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. Poly(propylene-co-ethylene) - ethylene content - <NUM>C NMR spectroscopy 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 (Singh, G. , Kothari, A. , Gupta, V. , Polymer Testing <NUM><NUM> (<NUM>), <NUM>).

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 (Cheng, H. , Macromolecules <NUM> (<NUM>), <NUM>) 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.

TGA according to the following procedure:
Thermogravimetric Analysis (TGA) experiments were performed with a Perkin Elmer TGA <NUM>. Approximately <NUM>-<NUM> of material was placed in a platinum pan. The temperature was equilibrated at <NUM> for <NUM> minutes, and afterwards raised to <NUM> under nitrogen at a heating rate of <NUM>/min. The weight loss between ca. <NUM> and <NUM> (WCO<NUM>) was assigned to CO<NUM> evolving from CaCO<NUM>, and therefore the chalk content was evaluated as: <MAT>.

Afterwards the temperature was lowered to <NUM> at a cooling rate of <NUM>/min. Then the gas was switched to oxygen, and the temperature was raised again to <NUM>. The weight loss in this step was assigned to carbon black (Wcb). Knowing the content of carbon black and chalk, the ash content excluding chalk and carbon black was calculated as: <MAT>.

Where Ash residue is the weight% measured at <NUM> in the first step conducted under nitrogen. The ash content is estimated to be the same as the talc content for the investigated recyclates.

Melt flow rates were measured with a load of <NUM> (MFR<NUM>) at <NUM>. 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> under a load of <NUM>.

was determined by x ray fluorescence (XRF).

Paper and wood were determined by conventional laboratory methods including milling, floatation, microscopy and Thermogravimetric Analysis (TGA).

Limonene quantification was carried out using solid phase microextraction (HS-SPME-GC-MS) by standard addition.

<NUM> ground samples were weighed into <NUM> headspace vials and after the addition of limonene in different concentrations and a glass-coated magnetic stir bar. the vial was closed with a magnetic cap lined with silicone/PTFE. Micro capillaries (<NUM> pL) were used to add diluted limonene standards of known concentrations to the sample. Addition of <NUM>, <NUM>, <NUM> and <NUM> ng equals <NUM>/kg, <NUM>/kg, <NUM>/kg and <NUM>/kg limonene, in addition standard amounts of <NUM>/kg, <NUM>/kg and <NUM>/kg limonene were used in combination with some of the samples tested in this application. For quantification, ion-<NUM> acquired in SIM mode was used. Enrichment of the volatile fraction was carried out by headspace solid phase microextraction with a <NUM> stable flex <NUM>/<NUM> pm DVB/Carboxen/PDMS fibre at <NUM> for <NUM> minutes. Desorption was carried out directly in the heated injection port of a GCMS system at <NUM>.

Fatty acid quantification was carried out using headspace solid phase micro-extraction (HS-SPME-GC-MS) by standard addition.

<NUM> ground samples were weighed in <NUM> headspace vial and after the addition of limonene in different concentrations and a glass coated magnetic stir bar the vial was closed with a magnetic cap lined with silicone/PTFE. <NUM>µL Micro-capillaries were used to add diluted free fatty acid mix (acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid and octanoic acid) standards of known concentrations to the sample at three different levels. Addition of <NUM>, <NUM>, <NUM> and <NUM> ng equals <NUM>/kg, <NUM>/kg, <NUM>/kg and <NUM>/kg of each individual acid. For quantification ion <NUM> acquired in SIM mode was used for all acids except propanoic acid, here ion <NUM> was used.

were determined by dynamic mechanical thermal analysis according to ISO <NUM>-<NUM>. The measurements were done in torsional deformation mode on compression moulded samples (40x10x1 mm<NUM>) between -<NUM> and +<NUM> with a heating rate of <NUM>/min and a frequency of <NUM> using TA Ares G2 test apparatus.

Compatibilizers CE1 and IE1 to IE4 were made in bench scale in a three-phase (bulk, gas phase <NUM> and gas phase <NUM>) polymerization setup.

The catalyst used in the polymerization processes of the inventive IE1-IE4 and comparative examples CE1 was prepared as follows:
Used chemicals:
<NUM> % solution in toluene of butyl ethyl magnesium (Mg(Bu)(Et), BEM), provided by Chemtura; <NUM>-ethylhexanol, provided by Amphochem; <NUM>-Butoxy-<NUM>-propanol - (DOWANOL™ PnB), provided by Dow; bis(<NUM>-ethylhexyl)citraconate, provided by SynphaBase; TiCl4, provided by Millenium Chemicals; Toluene, provided by Aspokem; Viscoplex® <NUM>-<NUM>, provided by Evonik; Heptane, provided by Chevron.

Preparation of a Mg alkoxy compound:
Mg alkoxide solution was prepared by adding, with stirring (<NUM> rpm), into <NUM> of a <NUM> wt% solution in toluene of butyl ethyl magnesium (Mg(Bu)(Et)), a mixture of <NUM> of <NUM>-ethylhexanol and <NUM> of butoxypropanol in a <NUM> stainless steel reactor. During the addition the reactor contents were maintained below <NUM>. After addition was completed, mixing (<NUM> rpm) of the reaction mixture was continued at <NUM> for <NUM> minutes. After cooling to room temperature <NUM> g of the donor bis(<NUM>-ethylhexyl)citraconate was added to the Mg-alkoxide solution keeping temperature below <NUM>. Mixing was continued for <NUM> minutes under stirring (<NUM> rpm).

Preparation of solid catalyst component:
<NUM> of TiCl4 and <NUM> of toluene were added into a <NUM> stainless steel reactor. Under <NUM> rpm mixing and keeping the temperature at <NUM>, <NUM> of the Mg alkoxy compound prepared in example <NUM> was added during <NUM> hours. <NUM> of Viscoplex® <NUM>-<NUM> and <NUM> of heptane were added and after <NUM> hour mixing at <NUM> the temperature of the formed emulsion was raised to <NUM> within <NUM> hour. After <NUM> minutes mixing was stopped catalyst droplets were solidified and the formed catalyst particles were allowed to settle. After settling (<NUM> hour), the supernatant liquid was siphoned away. Then the catalyst particles were washed with <NUM> of toluene at <NUM> for <NUM> minutes followed by two heptane washes (<NUM>, <NUM>). During the first heptane wash the temperature was decreased to <NUM> and during the second wash to room temperature.

The thus obtained catal st was used along with triethyl-aluminium (TEAL) as cocatalyst and dicyclopentyl dimethoxy silane (D-Donor) as donor.

The virgin polymer powders (IE1-IE4 and CE1) or pellets (CE2-CE4) were compounded with recycled material pellets (blend A #<NUM>, blend A #<NUM>) in a co-rotating twin-screw extruder ZSK-<NUM> Megalab at <NUM> with <NUM> wt% Irganox B225 antioxidant and <NUM> wt% calcium stearate to produce the recyclate containing compounds.

In the Comparative Example CE2 SB815MO was used.

In the Comparative Example CE3 ED007HP was used.

In the Comparative Example CE4 SC876CF was used.

Commercial grade SB815MO is available from Borealis AG, Austria and is a nucleated propylene-ethylene random heterophasic copolymer having a MFR of <NUM>/<NUM>, melting temperature of <NUM>, a total C2 content of <NUM> wt% and an XCS content of <NUM> wt%.

Commercial grade ED007HP is available from Borealis AG, Austria and is a nucleated propylene-ethylene heterophasic copolymer having a MFR of <NUM>/<NUM>, melting temperature of <NUM>, a total C2 content of <NUM> wt% and an XCS content of <NUM> wt%. Commercial grade SC876CF is available from Borealis AG, Austria and is a nucleated propylene-ethylene random heterophasic copolymer having a MFR of <NUM>/<NUM>, melting temperature of <NUM>, a total C2 content of <NUM> wt% and an XCS content of <NUM> wt%.

Table <NUM> summarizes the process conditions and the features obtained.

Table <NUM> shows the properties of the compatibilizers and compatibilizers used for comparative purposes.

Inventive Compatibilizer <NUM> had a moderately high IV(XCS) of <NUM> dl/g and moderate C2(XCS) of <NUM> wt. Inventive Compatibilizer <NUM> had a low IV(XCS) of <NUM> dl/g and relatively low C2(XCS) of <NUM> wt. Inventive Compatibilizer <NUM> had a high IV(XCS) of <NUM> dl/g and relatively low C2(XCS) of <NUM> wt. Inventive Compatibilizer <NUM> had a high IV(XCS) of <NUM> dl/g and moderate C2(XCS) of <NUM> wt. Comparative Compatibilizer <NUM> was a mixture of a propylene homopolymer and a random propylene ethylene copolymer. Comparative Compatibilizer <NUM> was a random heterophasic polypropylene copolymer with a low IV(XCS) of <NUM> dl/g and low C2(XCS) of <NUM> wt. Comparative Compatibilizer <NUM> was a heterophasic polypropylene copolymer with a high IV(XCS) of <NUM> dl/g and moderate C2(XCS) of <NUM> wt. Comparative Compatibilizer <NUM> was a random heterophasic polypropylene copolymer with a low IV(XCS) of <NUM> dl/g and moderate C2(XCS) of <NUM> wt.

Table <NUM> shows the properties of the polypropylene / polyethylene blends (A) as used for the evaluation.

Both blends showed inacceptable elongation at break properties.

Blend A #<NUM> and Blend A #<NUM> were blended with compatibilizers and comparative compatibilizers in varying amounts as described above.

It can be seen that all compatibilizers according to the present invention increase elongation at break to desirable values already in surprisingly low amount of <NUM> wt. At higher compatibilizer loadings of <NUM> w. -% this effect begins to disappear. Charpy NIS (+<NUM>) profits from increased compatibilizer loading, whereas Charpy NIS (-<NUM>) turned out to be less dependent on the compatibilizer loading. The improvement as to elongation at break could be achieved with marginal deterioration of stiffness of about <NUM> MPa. Very significant increase of the room temperature puncture resistance and especially cold puncture resistance was shown by the inventive compatibilizers <NUM>, <NUM> and <NUM> (by <NUM>-<NUM>%) at desirable low loadings of only <NUM>%. At desirable low loadings of compatibilizer, compatibilizers # <NUM> and #<NUM> according to the present invention both having relatively high IV(XCS) of <NUM> and <NUM> dl/g surprisingly showed the best balance of properties.

Claim 1:
Heterophasic copolymer for compatibilization of a polypropylene/polyethylene blend (A) said polypropylene/polyethylene blend (A) having one or more of the following properties:
(i) a content of limonene as determined by using solid phase microextraction (HS-SPME-GC-MS) of from <NUM> ppm to <NUM> ppm, preferably from <NUM> ppm to <NUM> ppm, more preferably from <NUM> ppm to <NUM> ppm, most preferably from <NUM> ppm to <NUM> ppm;
(ii) a content of fatty acid(s) as determined by using solid phase microextraction (HS-SPME-GC-MS) of <NUM> to <NUM> ppm
(iii) a content of polyamide(s) as determined by NMR of <NUM> to <NUM> wt.-%;
(iv) a content of polystyrene(s) as determined by NMR of <NUM> to <NUM> wt.-% whereby said heterophasic copolymer comprises a matrix phase and an elastomer phase dispersed therein, whereby the matrix phase includes a random polypropylene copolymer, and whereby
the heterophasic copolymer has
- a melt flow rate MFR<NUM> (<NUM>, ISO1133) of <NUM> to <NUM>/<NUM>, and
- at least one melting point Tm1 in the range of <NUM> to <NUM>,
- optionally a second melting point Tm2 in the range of <NUM> to <NUM>,
- optionally a second or third melting point Tm3 in the range of <NUM> to <NUM>,
- a xylene cold insoluble content (XCI) of from <NUM> to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-% (ISO <NUM>, 1ed, <NUM>), and
- a xylene cold soluble content (XCS) of <NUM> to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-% (ISO <NUM>, 1ed, <NUM>), wherein the xylene cold insoluble content (XCI) and the xylene cold soluble content (XCS) add up to <NUM> wt.-%.
- a content of units derived from ethylene in the xylene cold insoluble content (XCI) of from <NUM> to <NUM> wt.-%, preferably <NUM> to <NUM> wt.-% and
- a content of units derived from ethylene in the xylene cold soluble content (XCS) of <NUM> to <NUM> wt.-%, preferably of <NUM> to <NUM> wt.%;
the xylene cold soluble content (XCS) having an intrinsic viscosity (measured in decalin according to DIN ISO <NUM>/<NUM> at <NUM>) of <NUM> dl/g to less than <NUM> dl/g, preferably <NUM> to <NUM> dl/g, more preferably <NUM> to <NUM> dl/g, and whereby optionally the heterophasic copolymer has a tensile modulus of at least <NUM> MPa (measured according to ISO <NUM>-<NUM>).