High flow automotive exterior compound with excellent surface appearance

Abstract

The present invention relates to a propylene composition suitable for use in high flow automotive exterior compounds having excellent surface appearance, the composition comprising a modified polypropylene composition and an inorganic filler.

Description

[0001] This application is a divisional application of patent application no. 201780036031.4 filed on July 14, 2017 and titled "High flow automotive exterior compounds with superior surface appearance". TECHNICAL FIELD

[0002] The present invention relates to a composition comprising a modified polypropylene composition and an inorganic filler. The modified polypropylene composition is obtained by treating a polypropylene composition comprising a heterophasic composition and a plastomer with a peroxide. The present invention further relates to an article made from the composition. Furthermore, the present invention relates to a process for preparing the composition and the use of a peroxide for reducing tiger stripes of a polypropylene composition. BACKGROUND

[0003] Superior surface appearance of polypropylene composites for automotive interior and exterior applications is of utmost importance for many un-painted and visible parts. One common problem is flow marks, often referred to as "tiger stripes", i.e. alternating shiny and hazy portions on the surface of injection molded parts. Tiger stripes inherently reduce the surface quality of injection molded parts and composite design needs to provide robust solutions covering a wide tiger stripe free processing window.

[0004] One common approach to suppress tiger stripe formation is the use of specially designed PP-HECOs (often referred to as "tiger stripe killers") which have a dispersed rubber phase rich in propylene and high viscosity, which is added to the PP compound in certain amounts to reduce the elongation of the dispersed rubber particles under shear stress, leading to more round shaped elastomer phases, which are beneficial for good surface appearance.

[0005] Especially for high flow exterior applications with very demanding mechanical performance characteristics (e.g. bumpers with low wall thickness), this approach is facing some severe limitations since superior stiffness impact balance is an essential prerequisite for such applications. Such high flow exterior compounds usually contain a significant amount of rubber, typically an internal rubber of the PP-HECO and an external rubber which is an ethylene-a-olefin rubber. Since both the internal and the external rubber inherently contribute to tiger stripe formation, the use of such compositions leads to significant tiger stripe formation under industrial processing conditions.

[0006] In order to reduce or eliminate flow marks in these compounds, a rather high weight fraction of tiger stripe killers is required to achieve satisfactory results. Unfortunately, due to the high viscous rubber phase of the "tiger stripe killers", the addition of "tiger stripe killers" to reduce tiger stripes is often accompanied by a reduction of the flowability of the compounds.

[0007] Therefore, there is a need for a polypropylene composition suitable for automotive exterior compounds with improved surface appearance and high flow. Summary of the Invention

[0008] It was therefore an object of the present invention to provide a high-flow polymer composition which can be injection moulded to obtain automotive compounds showing reduced tiger stripes while maintaining a high level of mechanical properties.

[0009] Therefore, the present invention relates to a composition (C) comprising a modified polypropylene composition (mPP) and an inorganic filler (F), wherein the modified polypropylene composition (mPP) is obtained by treating a polypropylene composition (PP) with a peroxide (PO), the polypropylene composition (PP) comprising

[0010] (a) a heterogeneous composition (HECO) comprising

[0011] (a1) (semi)crystalline polypropylene (PP1), and

[0012] (a2) an elastomeric ethylene / propylene copolymer (EPR) dispersed in the (semi)crystalline polypropylene (PP1),

[0013] (b) a plastomer (PL) comprising ethylene and at least one C4 to C 20 Copolymers of α-olefins,

[0014] and

[0015] (c) optionally a high flow polypropylene (HPP) which preferably has a higher melt flow rate MFR2 (230°C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1).

[0016] Particularly preferably, the modified polypropylene composition (mPP) has

[0017] (i) a melt flow rate MFR2 (230°C) measured according to ISO 1133 of higher than 32 g / 10 min, and

[0018] (ii) a ratio IV(XCS) / IV(XCI) of at least 2.10, wherein IV(XCS) is the intrinsic viscosity IV of the xylene soluble fraction XCS, determined in accordance with DIN ISO 1628 / 1 (in decalin at 135° C.), and IV(XCI) is the intrinsic viscosity IV of the xylene insoluble fraction XCI, determined in accordance with DIN ISO 1628 / 1 (in decalin at 135° C.).

[0019] Alternatively to the preceding paragraph, the present application relates to a composition (C) comprising a modified polypropylene composition (mPP) and an inorganic filler (F), wherein the modified polypropylene composition (mPP) is obtained from a polypropylene composition (PP) comprising

[0020] (a) a heterophasic composition (HECO) comprising

[0021] (a1) a (semi)crystalline polypropylene (PP1), and

[0022] (a2) an elastomeric ethylene / propylene copolymer (EPR) dispersed in the (semi)crystalline polypropylene (PP1),

[0023] (b) a plastomer (PL) being a copolymer of ethylene and at least one C4 to C 20 α-olefin,

[0024] and

[0025] (c) optionally a high flow polypropylene (HPP), the high flow polypropylene (HPP) preferably having a higher melt flow rate MFR2(230 °C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1),

[0026] wherein the modified polypropylene composition (mPP) has

[0027] (i) a melt flow rate MFR2(230 °C) measured according to ISO 1133 higher than 32 g / 10 min, and

[0028] (ii) a ratio of IV(XCS) / IV(XCI) of at least 2.10, wherein IV(XCS) is the intrinsic viscosity IV of the xylene soluble fraction XCS determined according to DIN ISO 1628 / 1 (in decalin at 135 °C) and IV(XCI) is the intrinsic viscosity IV of the xylene insoluble fraction XCI determined according to DIN ISO 1628 / 1 (in decalin at 135 °C).

[0029] It is particularly preferred that the modified polypropylene composition (mPP) is obtained by treating the polypropylene composition (PP) with a peroxide (PO).

[0030] According to one embodiment of the present application, the plastomer (PL) is a copolymer of ethylene and 1-butene or 1-octene.

[0031] According to another embodiment of the present application, the modified polypropylene composition (mPP) has

[0032] (i) an intrinsic viscosity IV of the xylene soluble fraction XCS determined according to DIN ISO 1628 / 1 (in decaline at 135 °C) of below 2.30 dl / g, and

[0033] (ii) an intrinsic viscosity IV of the xylene insoluble fraction XCI determined according to DIN ISO 1628 / 1 (in decaline at 135 °C) of below 1.05 dl / g.

[0034] According to another embodiment of the present application, the weight ratio of the heterophasic composition (HECO) and the plastomer (PL) in the polypropylene composition (PP) [(HECO) / (PL)] is in the range of 0.1 to 10.0.

[0035] According to another embodiment of the present application, the polypropylene composition (PP) comprises 3 to 15 wt.-% of a high flow polypropylene (HPP) based on the total weight of the polypropylene composition (PP), the high flow polypropylene (HPP) preferably having a higher melt flow rate MFR2(230 °C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1).

[0036] It is particularly preferred that the composition (C) comprises

[0037] (a) 45 to 95 wt.-% of a modified polypropylene composition (mPP), and

[0038] (b) 5 to 30 wt.-% of an inorganic filler (F).

[0039] According to one embodiment of the present application, the heterophasic composition (HECO) has

[0040] (a) a comonomer content in the range of 3 to 20 wt.-% based on the total weight of the heterophasic composition (HECO), and / or

[0041] (b) a xylene soluble fraction (XCS) in the range of 10 to 35 wt.-%,

[0042] and / or

[0043] (c) a melt flow rate MFR2(230 °C) measured according to ISO 1133 of 40 to 100 g / 10 min.

[0044] According to another embodiment of the present application, the xylene soluble fraction (XCS) of the heterophasic composition (HECO) has

[0045] (a) an intrinsic viscosity (IV) determined according to DIN ISO 1628 / 1 (in decaline at 135 °C) in the range of 1.5 to 4.5 dl / g,

[0046] (b) a comonomer content in the range of 25 to 55 wt.-%, based on the total weight of the xylene soluble fraction (XCS) of the heterophasic composition (HECO).

[0047] According to another embodiment of the present application, the plastomer (P) has

[0048] (a) a melt flow rate MFR (190°C) measured according to ISO 1133 in the range of 0.05 to 5.0 g / 10 min,

[0049] (b) a comonomer content in the range of 5 to 25 mol-%, based on the total weight of the plastomer (PL), and

[0050] (c) a density equal to or below 0.880 g / cm3. 3

[0051] It is particularly preferred that the inorganic filler (F) is talc.

[0052] The present application also relates to an article comprising the composition (C) as described above, which is preferably an injection molded automotive article.

[0053] Furthermore, the present application also relates to the use of a peroxide (PO) for reducing tiger stripes of a polypropylene composition (PP) according to any of the preceding claims, wherein the composition (C) as described above is obtained.

[0054] It is particularly preferred that the reduction of tiger stripes is achieved at a MSE value equal to or below 30.

[0055] The present application also relates to a process for preparing the composition (C) as described above, wherein

[0056] (a)

[0057] (a1 ) extruding a polypropylene composition (PP) comprising the heterophasic composition (HECO), the plastomer (PL) and optionally the high flow polypropylene (HPP) in the presence of a peroxide (PO) in an extruder, thereby obtaining a modified polypropylene composition (mPP), and

[0058] (b1 ) melt blending the modified polypropylene composition (mPP) with the inorganic filler (F),

[0059] or

[0060] (b) extruding a polypropylene composition (PP) comprising the heterophasic composition (HECO), the plastomer (PL), the optional high flow polypropylene (HPP) and the inorganic filler (F) in the presence of a peroxide (PO) in an extruder. ​

[0061] According to the present application, a small amount of peroxide is added to a typical automotive exterior compound. The peroxide increases the melt flow rate, thus increasing the flowability through the visbreaking of the heterophasic composition (HECO). The peroxide changes the ratio between the intrinsic viscosities of the XCS and XCI fractions, thus changing the final morphology of the dispersed phase. Furthermore, the robustness of the presently claimed composition against shear elongation and final tiger stripe formation is increased. DETAILED DESCRIPTION

[0062] The present application will now be described in more detail.

[0063] Composition

[0064] The composition (C) according to the present application comprises a modified polypropylene composition (mPP) and an inorganic filler (F). The modified polypropylene composition (mPP) is obtained by treating a polypropylene composition (PP) with a peroxide (PO).

[0065] The polypropylene composition (PP) has to comprise a heterophasic composition (HECO) and a plastomer (PL). Optionally, the polypropylene composition can comprise a high flow polypropylene (HPP). Thus, in a preferred embodiment, the polypropylene composition (PP) and thus the modified polypropylene composition (mPP) comprises a heterophasic composition (HECO), a plastomer (PL) and a high flow polypropylene (HPP).

[0066] The composition (C) of the present application has to comprise a modified polypropylene composition (mPP) and an inorganic filler (F). Furthermore, the composition can comprise an alpha nucleating agent (NU) and an additive (AD). Thus, it is preferred that the modified polypropylene composition (mPP) and the inorganic filler (F) together constitute at least 80 wt.-%, more preferably at least 85 wt.-%, still more preferably at least 90 wt.-%, such as at least 95 wt.-% of the composition (C). In a particular embodiment, the composition (C) consists of the modified polypropylene composition (mPP) and the inorganic filler (F) and optionally the polymeric carrier material of the peroxide (P), the alpha nucleating agent (NU) and / or the additive (AD).

[0067] Preferably, the weight ratio between the modified polypropylene composition (mPP) and the inorganic filler (F) [(mPP) / (F)] is in the range of 2.0 to 10.0, more preferably in the range of 3.0 to 8.0, more preferably in the range of 5.0 to 7.0.

[0068] Thus, the composition (C) preferably comprises

[0069] (a) 45 to 95 wt.-%, more preferably 55 to 90 wt.-%, still more preferably 60 to 85 wt.-%, like 70 to 83 wt.-%, based on the total weight of the composition (C), of a modified polypropylene composition (mPP), and

[0070] (b) 5 to 30 wt.-%, more preferably 6 to 25 wt.-%, still more preferably 8 to 20 wt.-%, like 10 to 15 wt.-%, based on the total weight of the composition (C), of an inorganic filler (F).

[0071] As mentioned above, the modified polypropylene composition (mPP) is obtained by treating a polypropylene composition (PP) with a peroxide (PO). Preferred peroxides (PO) are listed in the section "Modified polypropylene composition (mPP)" below.

[0072] The peroxide (PO) is preferably introduced in the form of a masterbatch. That is, the peroxide (PO) is pre-mixed with a polymeric carrier material. Said polymeric carrier material does not contribute to the improved properties of the composition (C). Preferably, the polymeric carrier material is a polyethylene or a polypropylene, the latter being preferred. Typically, the polymeric carrier material is different from the heterophasic composition (HECO) and the plastomer (PL). Preferably, the polymeric carrier material is a propylene homopolymer. The amount of said polymeric carrier material is preferably in the range of 0.01 to 5 wt.-%, more preferably in the range of 0.02 to 2 wt.-%, still more preferably in the range of 0.1 to 1 wt.-%, like in the range of 0.1 to 0.5 wt.-%, based on the total weight of the composition (C).

[0073] Thus, the composition (C) preferably comprises

[0074] (a) 45 to 95 wt.-%, more preferably 55 to 90 wt.-%, still more preferably 60 to 85 wt.-%, like 70 to 83 wt.-%, based on the total weight of the composition (C), of a modified polypropylene composition (mPP), and

[0075] (b) 5 to 30 wt.-%, more preferably 6 to 25 wt.-%, still more preferably 8 to 20 wt.-%, like 10 to 15 wt.-%, based on the total weight of the composition (C), of an inorganic filler (F).

[0076] (c) 0.01 to 5 wt.-%, more preferably 0.02 to 2 wt.-%, still more preferably 0.1 to 1 wt.-%, like 0.1 to 0.5 wt.-%, based on the total weight of the composition (C), of a polymeric carrier material of a peroxide (P).

[0077] As mentioned above, the composition (C) can additionally comprise an alpha-nucleating agent (NU) and / or an additive (AD). According to the present application, neither the alpha-nucleating agent (NU) nor the filler (F) is an additive (AD). Furthermore, according to the present application, the filler (F) is not an alpha-nucleating agent (NU). It is therefore preferred that the composition (C) contains up to 5.0 wt.-%, preferably 1.0 x 10 -5 to 4.0 wt.-%, more preferably 2.0 x 10 -5 wt.-% of an alpha-nucleating agent (NU) and / or up to 8.0 wt.-%, preferably 0.1 to 6.0 wt.-%, more preferably 0.5 to 4.0 wt.-% of an additive (AD), based on the total weight of the composition.

[0078] It is therefore particularly preferred that the composition consists of:

[0079] (a) 35 to 80 wt.-%, more preferably 40 to 70 wt.-%, still more preferably 45 to 65 wt.-%, like 48 to 63 wt.-% of a modified polypropylene composition (mPP), based on the total weight of the composition (C),

[0080] (b) 5 to 30 wt.-%, more preferably 6 to 25 wt.-%, still more preferably 8 to 20 wt.-%, like 10 to 15 wt.-% of an inorganic filler (F), based on the total weight of the composition (C),

[0081] (c) 0.01 to 5 wt.-%, more preferably in the range of 0.02 to 2 wt.-%, still more preferably in the range of 0.1 to 1 wt.-%, like in the range of 0.1 to 0.5 wt.-% of a polymer carrier material for peroxide (P), based on the total weight of the composition (C),

[0082] (d) optionally up to 5.0 wt.-%, preferably 1.0 x 10 -5 to 4.0 wt.-%, more preferably 2.0 x 10 -5 wt.-% of an alpha-nucleating agent (NU), based on the total weight of the composition, and

[0083] (e) optionally up to 8.0 wt.-%, preferably 0.1 to 6.0 wt.-%, more preferably 0.5 to 4.0 wt.-% of an additive (AD), based on the total weight of the composition.

[0084] It is particularly preferred that the composition (C) has a melt flow rate MFR2 (230 °C, 2.16 kg) higher than 25 g / 10 min, more preferably in the range of 26 to 50 g / 10 min, more preferably in the range of 28 to 48 g / 10 min, like in the range of 30 to 45 g / 10 min.

[0085] In a preferred embodiment, the composition (C) has a density in the range of 0.890 to 0.990 g / cm3 in the range of 0.950 to 0.985 g / cm3, preferably in the range of 0.955 to 0.980 g / cm3, more preferably in the range of 0.960 to 0.978 g / cm3, even more preferably in the range of 0.965 to 0.975 g / cm3, and most preferably in the range of 0.970 to 0.975 g / cm3. 3 in the range of 0.950 to 0.985 g / cm3, preferably in the range of 0.955 to 0.980 g / cm3, more preferably in the range of 0.960 to 0.978 g / cm3, even more preferably in the range of 0.965 to 0.975 g / cm3, and most preferably in the range of 0.970 to 0.975 g / cm3. 3 in the range of 0.950 to 0.985 g / cm3, preferably in the range of 0.955 to 0.980 g / cm3, more preferably in the range of 0.960 to 0.978 g / cm3, even more preferably in the range of 0.965 to 0.975 g / cm3, and most preferably in the range of 0.970 to 0.975 g / cm3. 3 in the range of 0.950 to 0.985 g / cm3, preferably in the range of 0.955 to 0.980 g / cm3, more preferably in the range of 0.960 to 0.978 g / cm3, even more preferably in the range of 0.965 to 0.975 g / cm3, and most preferably in the range of 0.970 to 0.975 g / cm3.

[0086] Preferably, the composition (C) has a flexural modulus of less than 2000 MPa, more preferably in the range of 1000 to 1900 MPa, still more preferably in the range of 1200 to 1500 MPa, such as in the range of 1300 to 1490 MPa.

[0087] Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2. 2 Additionally or alternatively to the preceding paragraph, the composition (C) has a notched Izod impact strength (23 °C) of at least 5 kJ / m2, more preferably in the range of 5 to 30 kJ / m2, still more preferably in the range of 8 to 28 kJ / m2, such as in the range of 10 to 25 kJ / m2, and most preferably in the range of 12 to 20 kJ / m2.

[0088] The composition according to the present application can be pelletized and compounded using any of a variety of compounding and blending methods well known and commonly used in the art.

[0089] In the following, the individual components of the composition are defined in more detail.

[0090] Modified polypropylene composition (mPP)

[0091] As mentioned above, the modified polypropylene composition (mPP) is obtained by treating a polypropylene composition (PP) with a peroxide (PO). The polypropylene composition (PP) must comprise the heterophasic composition (HECO) and the plastomer (PL), and can additionally comprise the high flow polypropylene (HPP). In a preferred embodiment, the heterophasic composition (HECO), the plastomer (PL) and the optional high flow polypropylene (HPP) together constitute at least 80 wt.-%, more preferably at least 85 wt.-%, still more preferably at least 90 wt.-%, such as at least 95 wt.-% of the modified polypropylene composition (mPP). In a particular embodiment, the modified polypropylene composition (mPP) consists of the heterophasic composition (HECO), the plastomer (PL) and, optionally, the high flow polypropylene (HPP).

[0092] The polymeric carrier material of the peroxide (P), the alpha nucleating agent (NU) and the additives (AD) are not considered part of the modified polypropylene composition (mPP) but part of the final composition (C).

[0093] The weight ratio of the heterophasic composition (HECO) and the plastomer (PL) in the modified polypropylene composition (mPP) [(HECO) / (PL)] is preferably in the range of 0.1 to 10.0, more preferably in the range of 1.0 to 8.0, still more preferably in the range of 1.2 to 5.0, such as in the range of 2.6 to 4.0.

[0094] The weight ratio of the heterophasic composition (HECO) and the high flow polypropylene (HPP) in the modified polypropylene composition (mPP) [(HECO) / (HPP)] is preferably in the range of 1.0 to 20.0, more preferably in the range of 3.0 to 18.0, still more preferably in the range of 6.0 to 15.0, such as in the range of 8.0 to 12.0.

[0095] As can be seen from the term "modified", the polypropylene composition (mPP) is a composition which has been chemically treated by using a peroxide (PO), i.e. a polypropylene composition (PP). In the present case, the modified polypropylene composition (mPP) is a polypropylene composition (PP) which has been chemically modified due to crosslinking, branching of the individual polymer chains and / or an increased ratio between the intrinsic viscosities of the XCS and XCI fractions. As can be seen by high resolution microscopy, the modified polymer composition typically shows a coarsening of the rubber phase domains. The observation of coarse rubber particles can be due to an increased viscosity ratio (IV(XCS) / IV(XCI)) between the XCS and XCI fractions.

[0096] As mentioned above, in order to obtain the modified polypropylene composition (mPP), the polypropylene composition (PP) has to be treated with a peroxide.

[0097] As the modified polypropylene composition (mPP), the polypropylene composition (PP) has to comprise a heterophasic composition (HECO) and a plastomer (PL) and can additionally comprise a high flow polypropylene (HPP). In a preferred embodiment, the heterophasic composition (HECO), the plastomer (PL) and the optional high flow polypropylene (HPP) together constitute at least 80 wt.-%, more preferably at least 85 wt.-%, still more preferably at least 90 wt.-%, such as at least 95 wt.-% of the polypropylene composition (PP). In a particular embodiment, the polypropylene composition (PP) consists of the heterophasic composition (HECO), the plastomer (PL) and the optional high flow polypropylene (HPP).

[0098] The polymeric carrier material of the peroxide (P), the alpha nucleating agent (NU) and the additives (AD) are not considered part of the polypropylene composition (PP) but part of the final composition (C).

[0099] The weight ratio of the heterophasic composition (HECO) and the plastomer (PL) in the polypropylene composition (PP) [(HECO) / (PL)] is preferably in the range of 0.1 to 10.0, more preferably in the range of 1.0 to 8.0, still more preferably in the range of 1.2 to 5.0, like in the range of 2.6 to 4.0.

[0100] The weight ratio of the heterophasic composition (HECO) and the high flow polypropylene (HPP) in the polypropylene composition (PP) [(HECO) / (HPP)] is preferably in the range of 1.0 to 20.0, more preferably in the range of 3.0 to 18.0, still more preferably in the range of 6.0 to 15.0, like in the range of 8.0 to 12.0.

[0101] It is preferred that the modified polypropylene composition (mPP) has a melt flow rate MFR2(230 °C) measured according to ISO 1133 of higher than 32 g / 10 min, more preferably in the range of 33 to 55 g / 10 min, still more preferably in the range of 34 to 50 g / 10 min, like in the range of 35 to 45 g / 10 min.

[0102] In addition to the previous paragraph, it is preferred that the modified polypropylene composition (mPP) has a comonomer content in the range of 7.5 to 21.0 mol-%, more preferably in the range of 8.0 to 18.0 mol-%, still more preferably in the range of 10.0 to 14.0 mol-%.

[0103] Further, it is preferred that the intrinsic viscosity IV of the xylene soluble fraction XCS of the modified polypropylene composition (PP) determined according to DIN ISO 1628 / 1 (in decalin at 135 °C) is lower than 2.30 dl / g, more preferably lower than 2.29 dl / g.

[0104] In addition, it is preferred that the intrinsic viscosity IV of the xylene insoluble fraction XCI of the modified polypropylene composition (PP) determined according to DIN ISO 1628 / 1 (in decalin at 135 °C) is lower than 1.05 dl / g, more preferably lower than 1.04 dl / g, more preferably lower than 1.03 dl / g.

[0105] It is particularly preferred that the ratio of IV(XCS) / IV(XCI) of the modified polypropylene composition (mPP) is at least 2.10, more preferably at least 2.11, still more preferably at least 2.12, wherein IV(XCS) is the intrinsic viscosity IV of the xylene soluble fraction XCS determined according to DIN ISO 1628 / 1 (in decalin at 135 °C) and IV(XCI) is the intrinsic viscosity IV of the xylene insoluble fraction XCI determined according to DIN ISO 1628 / 1 (in decalin at 135 °C).

[0106] Further, it is preferred that the comonomer content of the xylene soluble fraction XCS of the modified polypropylene composition (mPP) is in the range of 20.0 to 70.0 mol-%, more preferably in the range of 35.0 to 65.0 mol-%, still more preferably in the range of 45.0 to 61.0 mol-%.

[0107] The respective properties of the heterophasic composition (HECO), the plastomer (PL) and the optional high flow polypropylene (HPP) in the polypropylene composition (PP) can be taken from the following information.

[0108] The modified peroxide (PO) for the polypropylene composition (PP) is preferably a thermally decomposing radical former. More preferably, the peroxide (PO), i.e. the thermally decomposing radical former, is selected from the group consisting of acyl peroxides, alkyl peroxides, hydroperoxides, peresters and peroxy carbonates.

[0109] The following listed peroxides are particularly preferred:

[0110] Acyl peroxides: benzoyl peroxide, 4-chlorobenzoyl peroxide, 3-methoxybenzoyl peroxide and / or methylbenzoyl peroxide.

[0111] Alkyl peroxides: allyl tert-butyl peroxide, 2,2-bis(tert-butylperoxybutane), 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 1,1 -bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl 4,4-bis(tert-butylperoxy)valerate, diisopropylaminomethyl-tert-amyl peroxide, dimethylaminomethyl-tert-amyl peroxide, diethylaminomethyl-tert-butyl peroxide, dimethylaminomethyl-tert-butyl peroxide, 1,1 -di-(tert-amylperoxy)cyclohexane, tert-amyl peroxide, tert-butyl cumyl peroxide, tert-butyl peroxide and / or 1 -hydroxybutyl n-butyl peroxide.

[0112] Peresters and peroxy carbonates: butyl peracetate, cumyl peracetate, cumyl perpropionate, cyclohexyl peracetate, di-tert-butyl peroxoadipate, di-tert-butyl peroxedisuccinate, di-tert-butyl peroxeglutarate, di-tert-butyl perphthalate, di-tert-butyl persebacate, 4-nitrophenyl perpropionate, 1-phenylethyl perbenzoate, phenethyl nitroperbenzoate, tert-butyl perbicyclo-(2,2,1)heptane carboxylate, tert-butyl 4-methoxycarbonyl perbutyrate, tert-butyl percyclobutane carboxylate, tert-butyl percyclohexyl carboxylate, tert-butyl percyclopentyl carboxylate, tert-butyl percyclopropane carboxylate, tert-butyl dimethyl percinnamate, tert-butyl 2-(2,2-diphenylvinyl)perbenzoate, tert-butyl 4-methoxyperbenzoate, tert-butyl perbenzoate, tert-butyl carboxyl cyclohexane, tert-butyl pernaphthoate, tert-butyl peroxyisopropyl carbonate, tert-butyl perpivalate, tert-butyl 1-phenylcyclopropyl percarboxylate, tert-butyl 2-propyl perpivalate, tert-butyl 1-methylcyclopropyl percarboxylate, tert-butyl 4-nitrophenyl peracetate, tert-butyl nitroperoxy carbamic acid, tert-butyl N-succinimidyl percarboxylate, tert-butyl percrotonate, tert-butyl permaleate, tert-butyl peroctoate, tert-butyl peroxyisopropyl carbonate, tert-butyl perisobutyrate, tert-butyl peracrylate and / or tert-butyl perpropionate, or mixtures of these radical formers listed above.

[0113] In a preferred embodiment, the peroxide (PO) is an alkyl peroxide. It is particularly preferred that the peroxide (PO) is 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane.

[0114] In a first embodiment of the modification process, the modified polypropylene composition (mPP) is obtained in a first step by extruding a polypropylene composition (PP) comprising the heterophasic composition (HECO), the plastomer (PL) and optionally the high flow polypropylene (HPP) in the presence of a peroxide (PO) in an extruder.

[0115] Subsequently, the modified polypropylene composition (mPP) is (melt) blended with the inorganic filler (F) to obtain the final composition (C).

[0116] In a second embodiment of the process, the polypropylene composition (PP) comprising the heterophasic composition (HECO), the plastomer (PL) and optionally the high flow polypropylene (HPP) and the inorganic filler (F) are extruded in the presence of a peroxide (PO) in an extruder to obtain the final composition (C).

[0117] The modification can be carried out, inter alia, by dosing the polypropylene composition (PP) or the mixture of polypropylene composition (PP) and inorganic filler (F) into a twin-screw extruder (e.g. ZSK 32) with a temperature profile of 80 / 200 / 210 / 220 / 220 / 230 / 230 / 220 / 225 / 220°C and a screw rotation speed of 300 rpm. The peroxide (PO) (e.g. 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane) is preferably added in the form of a masterbatch with polyolefin, which is dosed directly into the extruder with all components, obtaining a concentration of peroxide (PO) of 0.001 to 1.0% by weight based on the mixture. The polymer melt / liquid / gas mixture is passed through the extruder, then subjected to vigorous devolatilization, discharged and pelletized, thus obtaining the modified polypropylene composition (mPP) or the final composition (C).

[0118] The properties of the heterophasic composition (HECO), in particular of the ethylene / propylene copolymer (EPR) of the heterophasic composition (HECO), and of the plastomer (PL) can change due to the use of the peroxide (PO). This applies in particular to the intrinsic viscosity and the melt flow rate of the ethylene / propylene copolymer (EPR) of the heterophasic composition (HECO) and to the properties of the plastomer (PL). The properties of the matrix of the heterophasic composition (HECO), i.e. of the (semi)crystalline polypropylene (PP1), are not affected. In some cases, due to the use of the peroxide, the melt flow rate MFR2(230°C) of the (semi)crystalline polypropylene (PP1) and of the high flow polypropylene (HPP) can slightly increase.

[0119] Heterophasic composition (HECO)

[0120] As mentioned above, due to the use of the peroxide (PO), the properties of the heterophasic composition (HECO) can change. That is, the properties defined in this part can be different after the treatment of the heterophasic composition (HECO) with the peroxide (PO). The properties of the ethylene / propylene copolymer (EPR) and of the polypropylene matrix and, as a consequence, the viscosity, e.g. the intrinsic viscosity (IV), of the xylene soluble fraction (XCS) and of the xylene cold insoluble fraction (XCI) of the heterophasic composition (HECO) are affected to some extent.

[0121] The heterophasic composition (HECO) preferably comprises as matrix (semi)crystalline polypropylene (PP1) in which the elastomeric propylene copolymer (ERP) is dispersed. Thus, the elastomeric propylene copolymer (EPR) is (finely) dispersed in the (semi)crystalline polypropylene (PP1). In other words, the (semi)crystalline polypropylene (PP1) constitutes the matrix in which the elastomeric propylene copolymer (ERP) forms inclusions in the matrix, i.e. in the (semi)crystalline polypropylene (PP1). Thus, the matrix contains (finely) dispersed inclusions which are not part of the matrix, and which contain the elastomeric propylene copolymer (ERP). The term "inclusion" according to the present application shall preferably mean that the matrix and the inclusions form different phases within the heterophasic composition (HECO), which are visible, for example, by high resolution microscopy, such as electron microscopy or atomic force microscopy, or by dynamic mechanical thermal analysis (DMTA). In particular in DMTA, the presence of a heterophasic structure can be determined by the presence of at least two different glass transition temperatures.

[0122] Preferably, the heterophasic composition (HECO) has a melt flow rate MFR2(230 °C, 2.16 kg) in the range of 10 to 120 g / 10 min, more preferably in the range of 20 to 100 g / 10 min, still more preferably in the range of 40 to 80 g / 10 min.

[0123] As mentioned above, the heterophasic composition (HECO) according to the present application preferably comprises

[0124] (a) the (semi)crystalline polypropylene (PP1) as matrix (M), and

[0125] (b) the elastomeric propylene copolymer (EPR).

[0126] Preferably, the weight ratio [PP1 / EPR] between the (semi)crystalline polypropylene (PP1) and the elastomeric propylene copolymer (EPR) of the heterophasic composition (HECO) is in the range of 90 / 10 to 40 / 60, more preferably in the range of 85 / 15 to 45 / 55, still more preferably in the range of 83 / 17 to 50 / 50, such as in the range of 82 / 18 to 60 / 40.

[0127] Preferably, the heterophasic composition (HECO) has an ethylene content in the range of 5 to 25 mol%, more preferably in the range of 6 to 20 mol%, still more preferably in the range of 8 to 18 mol%, yet more preferably in the range of 10 to 15 mol%.

[0128] Preferably, the heterophasic composition (HECO) has a xylene cold soluble (XCS) fraction (25°C) in the range of 10 to 45 wt.-%, more preferably in the range of 12 to 35 wt.-%, still more preferably in the range of 15 to 30 wt.-% and most preferably in the range of 15 to 25 wt.-%.

[0129] Preferably, the ethylene content of the xylene cold soluble fraction (XCS) of the heterophasic composition (HECO) is in the range of 15 to 55 mol%, more preferably in the range of 25 to 52 mol%, still more preferably in the range of 35 to 50 mol%, still more preferably in the range of 40.0 to 48 mol%.

[0130] In a preferred embodiment, the intrinsic viscosity (IV) of the xylene cold soluble fraction (XCS) of the heterophasic composition (HECO) is at least 1.5 dl / g, more preferably at least 2.0 dl / g. On the other hand, the intrinsic viscosity (IV) should not be too high, otherwise the fluidity would be reduced. Therefore, the intrinsic viscosity of the xylene cold soluble fraction (XCS) of the heterophasic composition (HECO) is preferably in the range of 1.5 to 4.0 dl / g, more preferably in the range of 1.8 to 3.8 dl / g, and even more preferably in the range of 2.0 to 3.5 dl / g.

[0131] The (semi)crystalline polypropylene (PP1) is preferably a (semi)crystalline random propylene copolymer (R-PP1) or a (semi)crystalline propylene homopolymer (H-PP1), the latter being especially preferred.

[0132] In case the (semi)crystalline polypropylene (PP1) is a (semi)crystalline random propylene copolymer (R-PP1), it is understood that the (semi)crystalline random propylene copolymer (R-PP1) comprises monomers copolymerizable with propylene, e.g. comonomers such as ethylene and / or C4 to C 12 α-olefins, in particular ethylene and / or C4 to C8 α-olefins, such as 1-butene and / or 1-hexene. Preferably, the (semi-)crystalline random propylene copolymer (R-PP1) according to this invention comprises, in particular consists of, monomers copolymerizable with propylene from the group consisting of ethylene, 1-butene and 1-hexene. More specifically, the (semi-)crystalline random propylene copolymer (R-PP1) according to this invention comprises, in addition to propylene, units derived from ethylene and / or 1-butene. In a preferred embodiment, the (semi-)crystalline random propylene copolymer (R-PP1) comprises units derived from ethylene and propylene only.

[0133] Furthermore, it is appreciated that the (semi)crystalline random propylene copolymer (R-PP1) preferably has a comonomer content in the range of more than 0.3 to 1.5 mol.-%, more preferably in the range of more than 0.35 to 1.2 mol.-%, still more preferably in the range of 0.4 to 1.0 mol.-%.

[0134] Further, it is appreciated that the (semi)crystalline polypropylene (PP1), such as the (semi)crystalline propylene homopolymer (H-PP1), has a melt flow rate MFR2(230 °C) measured according to ISO 1133 in the range of 70 to 200 g / 10 min, more preferably in the range of 80 to 190 g / 10 min, still more preferably in the range of 100 to 180 g / 10 min, yet more preferably in the range of 130 to 170 g / 10 min.

[0135] Furthermore, it is preferred that the semi-crystalline polypropylene (PP1) according to the present application has a xylene soluble fraction (XCS) of not more than 10 wt.-%, even lower, i.e. not more than 5.0 wt.-%, if in the case of the (semi)crystalline propylene homopolymer (H-PP1).

[0136] Therefore, it is preferred that the (semi)crystalline propylene homopolymer (H-PP1) has a xylene soluble fraction (XCS) of less than 5.0 wt.-%, more preferably in the range of 0.5 to 4.5 wt.-%, such as in the range of 0.8 to 3.5 wt.-%.

[0137] The second component of the heterophasic composition (HECO) is an elastomeric propylene copolymer (EPR).

[0138] The elastomeric propylene copolymer (EPR) comprises, preferably consists of, units derived from (i) propylene and (ii) ethylene.

[0139] The elastomeric propylene copolymer (EPR) of the heterophasic composition (HECO) has an ethylene content in the range of 15 to 55 mol.-%, more preferably in the range of 25 to 52 mol.-%, still more preferably in the range of 35 to 50 mol.-%, yet more preferably in the range of 40.0 to 48 mol.-%.

[0140] The heterophasic composition (HECO) can be prepared by blending the (semi)crystalline polypropylene (PP1) and the elastomeric propylene copolymer (EPR). However, it is preferred that the heterophasic composition (HECO) is prepared in a sequential step process employing reactors in a series configuration and operated at different reaction conditions. As a result, each fraction prepared in a particular reactor can have its own molecular weight distribution and / or comonomer content distribution.

[0141] The heterophasic composition (HECO) according to the present application is preferably produced in a sequential polymerization process (i.e. a multi-stage process) known in the art, wherein the (semi)crystalline polypropylene (PP1) is produced in at least one slurry reactor, preferably in a slurry reactor and optionally in a subsequent gas phase reactor, and subsequently the elastomeric propylene copolymer (EPR) is produced in at least one (i.e. one or two) gas phase reactor(s).

[0142] Therefore, it is preferred that the heterophasic composition (HECO) is produced in a sequential polymerization process comprising the following steps:

[0143] (a) polymerizing propylene and optionally at least one ethylene and / or C4 to C 12 an alpha-olefin, obtaining a first polypropylene fraction of (semi)crystalline polypropylene (PP1), preferably the first polypropylene fraction is a propylene homopolymer,

[0144] (b) transferring the first polypropylene fraction into a second reactor (R2),

[0145] (c) polymerizing propylene and optionally at least one ethylene and / or C4 to C 12 an alpha-olefin in the presence of the first polypropylene fraction, thereby obtaining a second polypropylene fraction, preferably the second polypropylene fraction is a second propylene homopolymer, the first polypropylene fraction and the second polypropylene fraction forming a (semi)crystalline polypropylene (H-PP1), i.e. a matrix of the heterophasic composition (HECO),

[0146] (d) transferring the (semi)crystalline polypropylene (PP1) of step (c) into a third reactor (R3),

[0147] (e) polymerizing propylene and ethylene in the third reactor (R3) and in the presence of the (semi)crystalline polypropylene (PP1) obtained in step (c), an elastomeric propylene / ethylene copolymer fraction (EPR) being dispersed in the (semi)crystalline polypropylene (PP1), the (semi)crystalline polypropylene (PP1) and the elastomeric propylene copolymer (EPR) forming the heterophasic composition (HECO).

[0148] Of course, in the first reactor (R1) a second polypropylene fraction can be produced and in the second reactor (R2) a first polypropylene fraction can be obtained. The same is true for the elastomeric propylene copolymer phase.

[0149] Preferably, monomers are flashed between the second reactor (R2) and the third reactor (R3).

[0150] The term "sequential polymerization process" means that the heterophasic composition (HECO) is produced in at least two (e.g. three or four) reactors connected in series. Thus, the process comprises at least a first reactor (R1) and a second reactor (R2), more preferably a first reactor (R1), a second reactor (R2) and a third reactor (R3). The term "polymerization reactor" shall mean where the main polymerization takes place. Thus, in case the process consists of four polymerization reactors, this definition does not exclude the option that the whole process comprises a prepolymerization step in a prepolymerization reactor, for example. The term "consists of" is a closed expression only with respect to the main polymerization reactors.

[0151] The first reactor (R1) is preferably a slurry reactor (SR) and can be any continuous or simply agitated batch tank reactor or loop reactor operating in bulk or slurry. Bulk means polymerization in a reaction medium comprising at least 60% (w / w) monomer. According to the present application, the slurry reactor (SR) is preferably a (bulk) loop reactor (LR).

[0152] The second reactor (R2) can be like the first reactor a slurry reactor, such as a loop reactor, or alternatively the second reactor (R2) is a gas phase reactor (GPR).

[0153] The third reactor (R3) is preferably a gas phase reactor (GPR).

[0154] Such a gas phase reactor (GPR) can be any mechanically mixed reactor or fluidized bed reactor. Preferably, the gas phase reactor (GPR) comprises a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m / sec. It can thus be appreciated that the gas phase reactor is a fluidized bed type reactor preferably having a mechanical stirrer.

[0155] Thus, in a preferred embodiment, the first reactor (R1) is a slurry reactor (SR), such as a loop reactor (LR), and the second reactor (R2) and the third reactor (R3) are gas phase reactors (GPR). Thus, for the present process, at least three reactors, preferably three polymerization reactors, are employed connected in series, i.e. a slurry reactor (SR), such as a loop reactor (LR), a first gas phase reactor (GPR-1) and a second gas phase reactor (GPR-2). If desired, a prepolymerization reactor is placed before the slurry reactor (SR).

[0156] In another preferred embodiment, the first reactor (R1 ) and the second reactor (R2) are slurry reactors (SR), such as loop reactors (LR), while the third reactor (R3) is a gas phase reactor (GPR). Thus, for the present process, at least three reactors, preferably three polymerization reactors, are employed in series connection, i.e. two slurry reactors (SR), such as two loop reactors (LR), and a gas phase reactor (GPR-1 ). If desired, a prepolymerization reactor is placed before the first slurry reactor (SR).

[0157] A preferred multi-stage process is, for example, the "Loop-Gas" process such as developed by Borealis A / S, Denmark, described in patent literature such as EP 0887379, WO 92 / 12182, WO 2004 / 000899, WO 2004 / 1 1 1095, WO 99 / 24478, WO 99 / 24479 or WO 00 / 68315, referred to as the "Borstar® Technology).

[0158] Another suitable slurry-gas process is the Borealis Process.

[0159] Preferably, in the present process for preparing a heterophasic composition (HECO) as defined above, the conditions of the first reactor (R1 ) of step (a), i.e. the slurry reactor (SR), such as a loop reactor (LR), can be as follows:

[0160] - the temperature is in the range of 50°C to 1 10°C, preferably between 60°C and 100°C, more preferably between 68 and 95°C,

[0161] - the pressure is in the range of 20 bar to 80 bar, preferably between 40 bar and 70 bar,

[0162] - hydrogen can be added in a manner known per se to control the molar mass.

[0163] Subsequently, the reaction mixture from step (a) is transferred to the second reactor (R2), i.e. to step (c), which is a gas phase reactor (GPR-1 ), wherein the conditions of step (c) are preferably as follows:

[0164] - the temperature is in the range of 50°C to 130°C, preferably between 60°C and 100°C,

[0165] - the pressure is in the range of 5 bar to 50 bar, preferably between 15 bar and 35 bar,

[0166] - hydrogen can be added in a manner known per se to control the molar mass.

[0167] The conditions in the third reactor (R3), preferably the second gas phase reactor (GPR-2), are similar to those in the second reactor (R2).

[0168] The residence times in the three reactor zones can be different.

[0169] In one embodiment of the process for the preparation of polypropylene, the residence time in the bulk reactor, e.g. loop reactor, is in the range of 0.1 to 2.5 hours, e.g. in the range of 0.15 to 1.5 hours, and the residence time in the gas phase reactor is typically in the range of 0.2 to 6.0 hours, such as 0.5 to 4.0 hours.

[0170] If desired, the polymerization can be carried out in the first reactor (R1), i.e. the slurry reactor (SR), such as a loop reactor (LR), under supercritical conditions in a known manner and / or in a gas phase reactor (GPR) in a condensed mode.

[0171] Preferably, the process further comprises a prepolymerization using a catalyst system comprising a Ziegler-Natta procatalyst, an external donor and optionally a cocatalyst, as described in detail below.

[0172] In a preferred embodiment, the prepolymerization is carried out in liquid propylene in a bulk slurry polymerization, i.e. the liquid phase mainly comprises propylene and a small amount of other reactants and optionally inert components dissolved therein.

[0173] The prepolymerization reaction is typically carried out at a temperature in the range of 10°C to 60°C, preferably in the range of 15°C to 50°C, more preferably in the range of 20 to 45°C.

[0174] The pressure in the prepolymerization reactor is not critical, but must be sufficiently high to keep the reaction mixture in the liquid phase. Thus, the pressure can be in the range of 20 to 100 bar, e.g. in the range of 30 to 70 bar.

[0175] The catalyst components are preferably introduced in the prepolymerization step in their entirety. However, in case the solid catalyst component (i) and the cocatalyst (ii) can be fed separately, only a part of the cocatalyst can be introduced in the prepolymerization stage, the remainder being introduced in the subsequent polymerization stage. Likewise, in this case, it is necessary to introduce into the prepolymerization stage as much cocatalyst as to obtain a sufficient polymerization reaction therein.

[0176] Other components can also be added to the prepolymerization stage. Thus, hydrogen can be added to the prepolymerization stage to control the molecular weight of the prepolymer, as known in the art. Furthermore, antistatic additives can be used to prevent the particles from adhering to each other or to the walls of the reactor.

[0177] The precise control of the prepolymerization conditions and reaction parameters is within the skill of the art.

[0178] According to the present application, the heterophasic composition (HECO) is obtained by a multi-stage polymerization process as described above in the presence of a catalyst system comprising a Ziegler-Natta procatalyst containing the transesterification product of a lower alcohol and a phthalate ester as component (i).

[0179] The procatalyst employed according to the present application for the preparation of the heterophasic composition (HECO) is prepared by the following operations:

[0180] a) reacting a spray-crystallized or emulsion-solidified adduct of MgCl2and a C1-C2alcohol with TiCl4,

[0181] b) reacting the product of stage a) with a dialkyl phthalate of the formula (I) under conditions for transesterification between the C1to C2alcohol and the dialkyl phthalate of the formula (I) to form an internal donor,

[0182]

[0183] wherein R 1’ and R 2’ are independently at least a C5alkyl group,

[0184] c) washing the product of stage b), or

[0185] d) optionally reacting the product of step c) with additional TiCl4.

[0186] The procatalyst is prepared as defined for example in the patent applications WO 87 / 07620, WO 92 / 19653, WO 92 / 19658 and EP 0491566. The content of these documents is included herein by reference.

[0187] First an adduct of the formula MgCl2*nROH is formed, wherein R is a methyl or ethyl group and n is from 1 to 6, of MgCl2and a C1-C2alcohol. Preferably ethanol is employed as the alcohol.

[0188] The adduct, which is first melted and then spray-crystallized or emulsion-solidified, is used as catalyst carrier.

[0189] In a next step, the spray-crystallized or emulsion-solidified adduct of the formula MgCl2*nROH, wherein R is a methyl or ethyl group, preferably an ethyl group, and n is from 1 to 6, is contacted with TiCl4to form a titaniumized carrier, followed by

[0190] • adding to the titaniumized carrier the following compounds to form a first product

[0191] (i) a dialkyl phthalate of the formula (I), wherein R 1’ and R2’ is independently at least C5-alkyl, such as at least C8-alkyl,

[0192] or preferably

[0193] (ii) dialkyl phthalate of formula (I), wherein R 1’ and R 2’ are the same and are at least C5-alkyl, such as at least C8-alkyl,

[0194] or more preferably

[0195] (iii) a dialkyl phthalate of formula (I) selected from the group consisting of propylhexyl phthalate (PrHP), dioctyl phthalate (DOP), diisodecyl phthalate (DIDP) and tricosyl phthalate (DTDP), even more preferably, the dialkyl phthalate of formula (I) is dioctyl phthalate (DOP), such as diisooctyl phthalate or diethylhexyl phthalate, in particular diethylhexyl phthalate,

[0196] subjecting said first product to appropriate transesterification conditions (i.e. to a temperature above 100° C., preferably between 100 and 150° C., more preferably between 130 and 150° C.) to transesterify said methanol or ethanol with said ester groups of said dialkyl phthalate of formula (I) to form preferably at least 80 mol %, more preferably 90 mol %, most preferably 95 mol % of said dialkyl phthalate of formula (II),

[0197]

[0198] Among them, R 1 and R 2 is methyl or ethyl, preferably ethyl,

[0199] A dialkyl phthalate of formula (II) is an internal donor, and

[0200] - Recovering the transesterification product as the procatalyst composition (component (i)).

[0201] In a preferred embodiment, an adduct of the formula MgCl2*nROH, wherein R is methyl or ethyl and n is from 1 to 6, is melted and the melt is then preferably injected by gas into a cold solvent or cold gas, whereby the adduct crystallizes in a morphologically favorable form, as described, for example, in WO 87 / 07620.

[0202] The crystalline adduct is preferably used as a catalyst support and reacted as a procatalyst useful in the present application, as described in WO 92 / 19658 and WO 92 / 19653.

[0203] When the catalyst residues are removed by extraction, an adduct of the titaniumized support and the internal donor is obtained, in which the groups derived from the ester alcohol have been changed.

[0204] If sufficient titanium remains on the support, it will be the active element of the procatalyst.

[0205] Otherwise, titaniumization is repeated after the above treatment to ensure sufficient titanium concentration, thus ensuring sufficient activity.

[0206] Preferably, the procatalyst used according to the present application contains at most 2.5 wt.%, preferably at most 2.2 wt.% and more preferably at most 2.0 wt.% of titanium. Its donor content is preferably between 4 and 12 wt.%, more preferably between 6 and 10 wt.%.

[0207] More preferably, the procatalyst used according to the present application has been prepared using ethanol as alcohol and dioctyl phthalate (DOP) as dialkyl phthalate of formula (I), resulting in diethyl phthalate (DEP) as internal donor compound.

[0208] Still more preferably, the catalyst used according to the present application is the one described in the Examples section; in particular using dioctyl phthalate as dialkyl phthalate of formula (I).

[0209] For the preparation of the heterogeneous composition (HECO) according to the present application, the catalyst system used preferably comprises, in addition to the specific Ziegler-Natta procatalyst, as component (ii) an organometallic cocatalyst.

[0210] Thus, the cocatalyst is preferably selected from the group consisting of trialkylaluminium, such as triethylaluminium (TEA), dialkylaluminium chloride and alkylaluminium sesquichloride.

[0211] Component (iii) of the catalyst system used is an external donor represented by formula (Ilia) or (Illb). Formula (Ilia) is defined as follows

[0212] Si(OCH3)2R2 5 (Ilia)

[0213] wherein R 5 represents a branched alkyl group having 3 to 12 carbon atoms, preferably a branched alkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 4 to 12 carbon atoms, preferably a cycloalkyl group having 5 to 8 carbon atoms.

[0214] It is particularly preferred that R 5 is selected from the group consisting of isopropyl, isobutyl, isopentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

[0215] Formula (IIIb) is defined as follows

[0216] Si(OCH2CH3)3(NR x R y ) (IIIb)

[0217] wherein R x and R y may be the same or different, represent a hydrocarbyl group having 1 to 12 carbon atoms.

[0218] R x and R y are independently selected from the group consisting of a linear aliphatic hydrocarbyl group having 1 to 12 carbon atoms, a branched aliphatic hydrocarbyl group having 1 to 12 carbon atoms and a cyclic aliphatic hydrocarbyl group having 1 to 12 carbon atoms. It is particularly preferred that R x and R y are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decyl, iso-propyl, iso-butyl, iso-pentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

[0219] More preferably, R x and R y are the same, still more preferably R x and R y are both ethyl groups.

[0220] More preferably, the external donor has the formula (IIIa), such as dicyclopentyl dimethoxysilane [Si(OCH3)2(cyclopentyl)2] or diisopropyl dimethoxysilane [Si(OCH3)2(CH(CH3)2)2].

[0221] Most preferably, the external donor is dicyclopentyl dimethoxysilane [Si(OCH3)2(cyclopentyl)2].

[0222] In another embodiment, the Ziegler-Natta procatalyst can be modified by polymerizing a vinyl compound having the following formula in the presence of a catalyst system comprising a specific Ziegler-Natta procatalyst (component (i)), an external donor (component (iii) and optionally a co-catalyst (component (iii)):

[0223] CH2=CH-CHR 3 R 4

[0224] wherein R 3 and R 4together form a 5- or 6-membered saturated, unsaturated or aromatic ring, or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is used for the preparation of the heterophasic composition (HECO) according to the present application. The polymerized vinyl compound can be used as an alpha-nucleating agent.

[0225] With regard to the catalyst modification, reference is made to the international applications WO 99 / 24478, WO 99 / 24479 and in particular to WO 00 / 68315, which are incorporated herein by reference with regard to the reaction conditions involved in the catalyst modification as well as the polymerization reaction.

[0226] Plasticizer (PL)

[0227] As mentioned above, due to the use of the peroxide (PO), the properties of the plasticizer (PL) change. That is, the properties defined in this part can be different after the treatment of the plasticizer (PL) with the peroxide (PO). In particular, the density as well as the melt flow rate MFR2(190°C) are affected. However, the comonomer content is not affected.

[0228] The plasticizer (PL) can be any elastomeric polyolefin, provided that it is chemically different from the elastomeric ethylene / propylene copolymer (EPR) as defined herein. More preferably, the plasticizer (PL) is a very low density polyolefin, more preferably a very low density polyolefin polymerized using single-site catalysis, preferably metallocene catalysis. Typically, the plasticizer (PL) is an ethylene copolymer.

[0229] In a preferred embodiment, the plasticizer (PL) has a density equal to or below 0.880 g / cm3. 3 More preferably, the plasticizer (PL) has a density equal to or below 0.879 g / cm3. 3 Still more preferably in the range of 0.860 to 0.879 g / cm3, such as in the range of 0.864 to 0.875 g / cm3. 3 3

[0230] Preferably, the plasticizer (PL) has a melt flow rate MFR2(190°C, 2.16 kg) in the range of less than 50 g / 10 min, more preferably 0.05 to 20 g / 10 min, still more preferably 0.1 to 10 g / 10 min, such as 0.1 to 5 g / 10 min.

[0231] Preferably, the plasticizer (PL) comprises units derived from ethylene and a C4 to C20 alpha-olefin.

[0232] ​​The plastomer (PL) comprises units derived from (i) ethylene and (ii) at least another C4to C20 α-olefin, such as a C4to C10 α-olefin, more preferably units derived from (i) ethylene and (ii) at least another α-olefin selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene, preferably the plastomer (PL) consists of units derived from (i) ethylene and (ii) at least another C4to C20 α-olefin, such as a C4to C10 α-olefin, more preferably the plastomer (PL) consists of units derived from (i) ethylene and (ii) at least another α-olefin selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. It is particularly preferred that the plastomer (PL) comprises at least units derived from (i) ethylene and (ii) 1-butene or 1-octene.

[0233] In a particularly preferred embodiment, the plastomer (PL) consists of units derived from (i) ethylene and (ii) 1-butene or 1-octene.

[0234] The comonomer content, such as the C4to C20 α-olefin content, of the plastomer (PL) is in the range of 20 to 60 wt%, more preferably in the range of 25 to 55 wt%, still more preferably in the range of 27 to 50 wt%, such as in the range of 29 to 42 wt%.

[0235] In a preferred embodiment, the elastomer (E) is prepared with at least one metallocene catalyst. The elastomer (E) can also be prepared with more than one metallocene catalyst, or the elastomer (E) can be a blend of multiple elastomers prepared with different metallocene catalysts. In some embodiments, the elastomer (E) is a substantially linear ethylene polymer (SLEP). SLEPs and other metallocene catalyzed elastomers (E) are known in the art, for example from US5272236. These resins are also commercially available, for example Queo TM Plastomer, ENGAGE TM Plastomer resin or EXACT TM Polymer or TAFMER TM Polymer.

[0236] High flow polypropylene (HPP)

[0237] In a preferred embodiment of the present application, the polypropylene composition comprises a heterophasic composition (HECO) as defined above, a plastomer (PL) as defined above and a high flow polypropylene (HPP). The high flow polypropylene (HPP) will also be affected by the peroxide, but to a lesser extent. If so, the melt flow rate will increase slightly further.

[0238] The high flow polypropylene (HPP) is preferably a high flow propylene random copolymer (R-HPP) or a high flow propylene homopolymer (H-HPP). It is particularly preferred that the high flow polypropylene (HPP) is a high flow propylene homopolymer (H-HPP).

[0239] In case the high flow polypropylene (HPP) is a high flow random propylene copolymer (R-HPP), it is understood that the high flow random propylene copolymer (R-HPP) comprises monomers copolymerizable with propylene, e.g. comonomers, such as ethylene and / or C4to C8a-olefins, e.g. 1 -butene and / or 1 -hexene. Preferably, the high flow random propylene copolymer (R-HPP) according to the present application comprises comonomers copolymerizable with propylene from the group consisting of ethylene, 1 -butene and 1 -hexene, in particular consists of comonomers copolymerizable with propylene from the group consisting of ethylene, 1 -butene and 1 -hexene. More specifically, the high flow random propylene copolymer (R-HPP) of the present application comprises, in addition to propylene, units derived from ethylene and / or 1 -butene. In a preferred embodiment, the high flow random propylene copolymer (R-HPP) comprises only units derived from ethylene and propylene. 12 a-olefins, in particular ethylene and / or C4to C8a-olefins, e.g. 1 -butene and / or 1 -hexene. Preferably, the high flow random propylene copolymer (R-HPP) according to the present application comprises comonomers copolymerizable with propylene from the group consisting of ethylene, 1 -butene and 1 -hexene, in particular consists of comonomers copolymerizable with propylene from the group consisting of ethylene, 1 -butene and 1 -hexene. More specifically, the high flow random propylene copolymer (R-HPP) of the present application comprises, in addition to propylene, units derived from ethylene and / or 1 -butene. In a preferred embodiment, the high flow random propylene copolymer (R-HPP) comprises only units derived from ethylene and propylene.

[0240] Furthermore, it is understood that the comonomer content of the high flow random propylene copolymer (R-HPP) is preferably in the range of more than 0.3 to 1.5 mol-%, more preferably in the range of more than 0.35 to 1.2 mol-%, still more preferably in the range of 0.4 to 1.0 mol-%.

[0241] Preferably, the high flow polypropylene (HPP) has a higher melt flow rate MFR2(230 °C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1) which is the matrix (M) of the heterophasic composition (HECO).

[0242] It is particularly preferred that the high flow polypropylene (HPP) has a melt flow rate MFR2(230 °C) measured according to ISO 1133 of more than 200 g / 10 min, more preferably of more than 300 g / 10 min, still more preferably of more than 600 g / 10 min, like in the range of 700 to 1000 g / 10 min.

[0243] Preferably, the polypropylene composition (PP) comprises 3 to 15 wt.-%, more preferably 5 to 12 wt.-%, still more preferably 6 to 10 wt.-% of the high flow polypropylene (HPP), based on the total weight of the polypropylene composition (PP).

[0244] Inorganic filler (F)

[0245] As a further requirement for the composition according to the present application is the presence of an inorganic filler (F). Thus, the filler (F) is not considered to be comprised in the additives (AD) defined in more detail below.

[0246] Preferably, the inorganic filler (F) is a mineral filler. It can be appreciated that the inorganic filler (F) is a phyllosilicate, a mica or a wollastonite. More preferably, the inorganic filler (F) is selected from the group consisting of mica, wollastonite, kaolinite, montmorillonite, smectite and talc. The most preferred inorganic filler (F) is talc.

[0247] It can be appreciated that the filler (F) has a median particle size (D 50 ) in the range of 0.8 to 20 pm and a top cut particle size (D 95 ) in the range of 10 to 20 pm, preferably a median particle size (D 50 ) in the range of 5.0 to 8.0 pm and a top cut particle size (D 95 ) in the range of 12 to 17 pm, more preferably a median particle size (D 50 ) in the range of 5.5 to 7.8 pm and a top cut particle size (D 95 ) in the range of 13 to 16.5 pm.

[0248] According to the present application, the filler (F) does not belong to the class of alpha nucleating agents (NU) and additives (AD).

[0249] The filler (F) is a product of the prior art and is commercially available.

[0250] Alpha nucleating agent (NU)

[0251] In one embodiment of the present application, the composition (C) comprises an alpha-nucleating agent, more preferably the composition is free of beta-nucleating agents.

[0252] According to the present application, the alpha nucleating agent (NU) is not an additive (AD).

[0253] The alpha-nucleating agent is preferably selected from the group consisting of:

[0254] (i) salts of mono- and poly-carboxylic acids, such as sodium benzoate or aluminium tert-butylbenzoate, and

[0255] (ii) dibenzylidene sorbitols (e.g. 1,3:2,4 dibenzylidene sorbitol) and C1-C8 alkyl substituted dibenzylidene sorbitol derivatives such as methyl dibenzylidene sorbitol, ethyl dibenzylidene sorbitol or dimethyl dibenzylidene sorbitol (e.g. 1,3:2,4 bis(methylbenzylidene) sorbitol), or substituted nonitol derivatives, for example 1,2,3,-trideoxy-4,6:5,7-bis-0-[(4-propylphenyl)methylene]-nonitol, and

[0256] (iii) salts of diesters of phosphoric acid, for example sodium 2,2'-methylenebis(4,6,-di-tert- butylphenyl)phosphate or bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl)phosphoric acid]hydroxyaluminum, and

[0257] (iv) vinyl cycloalkane polymers and vinyl alkane polymers, and

[0258] (v) mixtures thereof.

[0259] Preferably, the alpha-nucleating agent comprised in the composition of the present application is a vinyl cycloalkane polymer and / or a vinyl alkane polymer, more preferably a vinyl cycloalkane polymer, such as a vinyl cyclohexane (VCH) polymer. A vinyl cyclohexane (VCH) polymer is particularly preferred as alpha-nucleating agent. It is understood that the amount of vinyl cycloalkane (such as vinyl cyclohexane (VCH)) polymer and / or vinyl alkane polymer, more preferably the amount of vinyl cyclohexane (VCH) polymer, in the composition does not exceed 500 ppm, preferably does not exceed 200 ppm, more preferably does not exceed 100 ppm, such as in the range of 0.1 to 500 ppm, preferably in the range of 0.5 to 200 ppm, more preferably in the range of 1 to 100 ppm. Further, it is understood that the vinyl cycloalkane polymer and / or vinyl alkane polymer is introduced into the composition by means of the BNT technology. With respect to the BNT technology, reference is made to international applications WO 99 / 24478, WO 99 / 24479 and in particular WO 00 / 68315. According to this technology, a catalyst system, preferably a Ziegler-Natta procatalyst, can be modified by polymerizing a vinyl compound in the presence of a catalyst system comprising in particular a specific Ziegler-Natta procatalyst, an external donor and a cocatalyst, wherein the vinyl compound has the following formula:

[0260] CH2=CH-CHR 3 R 4

[0261] wherein R 3 and R 4together form a 5- or 6-membered saturated, unsaturated or aromatic ring, or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is preferably used for the preparation of a heterophasic composition (HECO) present in the modified polypropylene composition (mPP). A vinyl compound is used as an alpha-nucleating agent. The weight ratio of the vinyl compound to the solid catalyst component in the modification step of the catalyst is preferably up to 5 (5:1), more preferably up to 3 (3:1), such as in the range of 0.5 (1:2) to 2 (2:1).

[0262] Such nucleating agents are commercially available and described, for example, in the "Plastic Additives Handbook", 5thEdition 2001 by Hans Zweifel, pages 967 to 990.

[0263] additives (AD)

[0264] In addition to the modified polypropylene composition (mPP) and the inorganic filler (F), the composition (C) of the present application can comprise additives (AD). Typical additives are acid scavengers, antioxidants, colorants, light stabilizers, plasticizers, slip agents, mar agents, dispersants, processing aids, lubricants, pigments, etc. As mentioned above, the inorganic filler (F) is not considered as an additive (AD).

[0265] Such additives are commercially available and described, for example, in the "Plastic Additives Handbook", 6thEdition 2009 by Hans Zweifel, pages 1141 to 1190.

[0266] Furthermore, the term "additives (AD)" according to the present application also includes carrier materials, in particular polymeric carrier materials.

[0267] polymeric carrier materials

[0268] Preferably, the composition (C) of the present application does not comprise more than 15 wt.-%, preferably more than 10 wt.-%, more preferably more than 9 wt.-%, based on the weight of the composition (C), of (a) further polymers different from the modified polypropylene composition (mPP), i.e. different from the heterophasic composition (HECO) and the plastomer (PL). If other polymers are present, such polymers are typically polymeric carrier materials for the peroxide (PO) and the additives (AD). Any carrier material for the additives (AD) is not counted to the amount of the polymeric compounds as indicated in the present application, but to the amount of the respective additive.

[0269] Therefore, in the present invention, there is a difference between the polymeric carrier material of the peroxide (PO) and the polymeric carrier material of the additive (AD). As mentioned above, the polymeric carrier material of the peroxide (PO) is considered separately, while the polymeric carrier material of the additive (AD) is considered as part of the additive (AD).

[0270] The polymeric carrier material of the additive (AD) is a carrier polymer ensuring homogeneous distribution in the composition (C) of the present invention. The polymeric carrier material is not limited to a specific polymer. The polymeric carrier material can be an ethylene homopolymer, an ethylene copolymer obtained from ethylene and an alpha-olefin comonomer such as a C3 to C8 alpha-olefin comonomer, a propylene homopolymer and / or a propylene copolymer obtained from propylene and an alpha-olefin comonomer such as ethylene and / or a C4 to C8 alpha-olefin comonomer.

[0271] Article

[0272] The composition of the present invention is preferably used for the preparation of an article, more preferably for the preparation of a shaped article, still more preferably for the preparation of an injection molded article. Even more preferred is the use for the preparation of parts of a washing machine or dishwasher and of automotive articles, in particular parts of the interior and exterior of a car, such as bumpers, side wall linings, step assists, body panels, spoilers, dashboards, interior linings and the like.

[0273] The present invention also provides an article, more preferably a shaped article, such as an injection molded article, comprising the composition of the present invention, preferably comprising at least 60 wt.-%, more preferably at least 80 wt.-%, still more preferably at least 95 wt.-% of the composition of the present invention, such as consisting of the composition of the present invention. Thus, the present invention relates in particular to parts of a washing machine or dishwasher and to automotive articles, in particular to parts of the interior and exterior of a car, such as bumpers, side wall linings, step assists, body panels, spoilers, dashboards, interior linings and the like, comprising the composition of the present invention, preferably comprising at least 60 wt.-%, more preferably at least 80 wt.-%, still more preferably at least 95 wt.-% of the composition of the present invention, such as consisting of the composition of the present invention.

[0274] Use

[0275] The present invention also relates to the use of a peroxide (PO) for reducing tiger stripes of a polypropylene composition (PP), wherein a composition (C) is obtained, said composition (C) comprising a modified polypropylene composition (mPP) and an inorganic filler (F). With regard to the definition of the composition (C), the modified polypropylene composition (mPP), the polypropylene composition (PP) and the inorganic filler (F), reference is made to the information provided above.

[0276] Reduction of tiger stripes is preferably achieved with an MSE value equal to or lower than 30, more preferably in the range of 1-20, and even more preferably in the range of 1-7.

[0277] The present invention will now be described in further detail by way of the examples provided below.

[0278] Example

[0279] 1. Definition / Measurement Method

[0280] Unless defined otherwise, the following definitions of terms and assay methods apply to the above general description of the invention and the following examples.

[0281] Quantification of microstructure by NMR spectroscopy

[0282] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers. 1 H and 13 Quantitative NMR spectra were recorded in solution on a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz, respectively. 13 C{ 1 H} NMR spectrum. 13A C-optimized 10 mm extended temperature probe recorded all spectra, using nitrogen gas for all pneumatic devices. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) with chromium(III) acetylacetonate (Cr(acac)3) to obtain a 65 mM solution of relaxer in solvent (Singh, G, Kothari, A., Gupta, V., Polymer Testing 28 (2009), 475). To ensure a homogeneous solution, the NMR tube was further heated in a rotating oven for at least 1 h after the initial sample was prepared in the heating block. After insertion into the magnet, the tube was spun at 10 Hz. This setting was chosen mainly for high resolution and accurate ethylene content quantification requires this setting. A standard single pulse excitation without NOE was employed using an optimized tip angle, a recycle delay of 1 s and a two-step WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G, Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transients were acquired per spectrum.

[0283] The quantitative 13 C{ 1 H}NMR spectra were processed, integrated and the relevant quantitative properties were determined from the integrals. All chemical shifts were indirectly referenced to the center methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allows a comparable reference even if this structural unit is not present. Characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, H. N., Macromolecules 17 (1984), 1950).

[0284] For the observed characteristic signals corresponding to 2,1 red region defects (as described in L. Resconi, L Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100(4), 1253, in Cheng, H. N., Macromolecules 1984, 17, 1950 and in W-J. Wang and S. Zhu, Macromolecules 2000, 33, 1157), the influence of the region defects on the determined properties needs to be corrected. No characteristic signals corresponding to other types of region defects were observed.

[0285] The method of Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) was adopted to quantify the comonomer fraction by integrating the multiple signals over the whole spectral region of the 13 C{ 1 H} spectra. This method was chosen because of its robust nature and the ability to account for the presence of region defects if needed. The integration region was slightly adjusted to improve the applicability over the whole range of comonomer contents encountered.

[0286] For systems where only isolated ethylene in the PPEPP sequence was observed, the method of Wang et al. was modified to reduce the influence of the non-zero integration of sites that are known to be absent. This method reduces the overestimation of the ethylene content for this system and is achieved by reducing the number of sites used to determine the absolute ethylene content to the following:

[0287] E = 0.5 (Sββ + Sβγ + Sβδ + 0.5 (Sαβ + Sαγ)).

[0288] By adopting this set of sites, the corresponding integration equations become, using the same notation as in the article of Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157):

[0289] E = 0.5 (I 11 + I G + 0.5 (I C + I D ))

[0290] The equation for the absolute propylene content was not changed.

[0291] The mole fraction of comonomer incorporation was calculated from the mole fraction:

[0292] E [mol%] = 100 * fE.

[0293] The weight percent of comonomer incorporation is calculated from the mole fraction:

[0294] E [wt%] = 100 * (fE* 28.06) / ((fE* 28.06) + ((1 - fE)* 42.08).

[0295] The comonomer sequence distribution at triad level is determined using the analytical method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method is chosen for its robustness, with slight adjustment of the integration region to increase the adaptability to a broader range of comonomer contents.

[0296] The ethylene content of the ethylene / propylene copolymer (EPR) is calculated:

[0297]

[0298] where

[0299] w(A) is the weight fraction [in wt%] of the (semi)crystalline polypropylene (PP1),

[0300] w(B) is the weight fraction [in wt%] of the ethylene / propylene copolymer (EPR),

[0301] C(A) is the comonomer content [in mol%] of the (semi)crystalline polypropylene (PP1),

[0302] C(P) is the comonomer content [in mol%] of the heterophasic composition (HECO),

[0303] C(B) is the calculated comonomer content [in mol%] of the ethylene / propylene copolymer (EPR).

[0304] Quantification of the comonomer content in the plastomer by NMR spectroscopy

[0305] Quantitative nuclear magnetic resonance (NMR) spectroscopy is utilized for quantifying the comonomer content of polymers. The comonomer content is determined by 13C NMR spectroscopy using the method of Wild et al. (Wild, L.; Bruzaud, J.; Guellal, A.; Bourgeois, C. Macromol. Chem. Phys. 200 1, 202, 1727-1736) and the method of Karjomehli et al. (Karjomehli, K.; Lofgren, B. Macromol. Chem. Phys. 1990, 191, 1983-1993). 1 H and 13 Bruker Advance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for H and C, respectively, is used to record quantitative 13 C{ 1 H} NMR spectra in the molten state. The quantitative 13C-optimized 7 mm magic angle spinning (MAS) probehead recorded all spectra, nitrogen gas was used for all pneumatic devices. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4 Hz. This setup was chosen mainly for the high sensitivity required for fast identification and accurate quantification [Klimke, K., Parkinson, M., Piel, C, Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382; Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208: 2128; Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373]. Standard single-pulse excitation was employed with transient NOE at a short recycle delay of 3 s [Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C, Kaminsky, W., Macromolecules 2004; 37: 813; Klimke, K., Parkinson, M., Piel, C, Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382] and RS-HEPT decoupling scheme [Filip, X., Tripon, C, Filip, C, J. Mag. Resn. 2005, 176, 239, Griffin, J. M., Tripon, C, Samoson, A., Filip, C, and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198]. A total of 1024 (1 k) transient values were co-added for each spectrum. This setup was chosen due to its high sensitivity towards low comonomer contents. The quantitative 13 C{ 1 H}NMR spectra were processed, integrated and quantitative performance was determined using a custom-made spectral analysis automation program. All chemical shifts were internally referenced to the bulk methylene signal (δ+) at 30.00 ppm [J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201].

[0306] Characteristic signals corresponding to incorporation of comonomer were observed [J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201] and all contents are calculated relative to the total of all other monomers present in the polymer.

[0307] [For more information see Zhou, Z., Kuemmerle, R., Qiu, x., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225 and Busico, V, Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G, Macromol. Rapid Commun. 2007, 28, 1128]

[0308] The comonomer content in the plastomer (PL) was measured using a Nicolet Magna 550 IR spectrometer and Nicolet Omnic FTIR software based on the use of 13 Fourier transform infrared spectroscopy (FTIR) calibrated with C-NMR was measured in a known way. Films with a thickness of about 250 μm were compression molded from the sample. Similar films were made from calibration samples with known comonomer content. The comonomer content was determined from the spectrum in the wave number range of 1430 to 1100 cm-1. The absorbance was measured as the height of the peak by choosing either the so-called short baseline or the long baseline or both. The short baseline is drawn through the minima between about 1410 and 1320 cm-1, the long baseline between about 1410 and 1220 cm-1. Special calibration is needed for each baseline type. Furthermore, the comonomer content of the unknown sample needs to be within the range of the comonomer contents of the calibration samples. 1 1 1

[0309] MFR2(230 °C) is measured according to ISO 1133 (230 °C, 2.16 kg load).

[0310] MFR2(190 °C) is measured according to ISO 1133 (190 °C, 2.16 kg load).

[0311] Xylene cold soluble (XCS, wt.%) The xylene cold soluble (XCS) content is determined according to ISO 16152; 1st Edition; 2005-07-01 at 25 °C.

[0312] ​​​The intrinsic viscosity is measured according to DIN ISO 1628 / 1, October 1999 (at 135°C in decalin).

[0313] The density is measured according to ISO 1 183-187. Sample preparation is done by compression moulding according to ISO 1872-2:2007.

[0314] The flexural modulus and the flexural strength are measured on 80x10x4mm injection moulded bars according to EN ISO 1873-2. 3 The test bars are measured according to ISO 178 at 23°C with 3 point bending.

[0315] The tensile modulus and the tensile strain at break are measured according to ISO 527-2 (crosshead speed = 1 mm / min; test speed 50 mm / min at 23°C) by using injection moulded test specimens (dog-bone, 4 mm thick) as described in EN ISO 1873-2. The measurements are performed after conditioning the specimens for 96 hours.

[0316] The Charpy notched impact strength is measured according to ISO 180 / 1A at 23°C and -20°C by using injection moulded test specimens (80x10x4mm) as described in EN ISO 1873-2.

[0317] The heat deflection temperature is measured according to ISO 75-2: Method A and Method B.

[0318] Shrinkage: The shrinkage is measured on centre gated, injection moulded discs (diameter 180 mm, thickness 3 mm, with a flow angle of 355° and a notch of 5°). Two specimens are moulded with two different dwell times (10 s and 20 s, respectively). The melt temperature at the gate is 260°C and the average flow front velocity in the mould is 100 mm / s. Tool temperature: 40°C, back pressure: 600 bar.

[0319] The dimensional changes in the radial and tangential direction of flow of the two discs are measured after conditioning the specimens for 96 hours at room temperature. The average of the respective values of the two discs is recorded as the final result.

[0320] Flow Marks

[0321] The tendency to show flow marks is detected with the method described below. This method is described in detail in WO 2010 / 149529, which is incorporated herein in its entirety.

[0322] The surface quality is characterized with an optical measurement system as described by Sybille Frank et al. in PPS 25 Intern. Conf. Polym. Proc. Soc 2009 or Proceedings of the SPIE, Vol. 6831, pp. 68130T-68130T-8 (2008).

[0323] The method consists of two parts:

[0324] 1. Image recording:

[0325] The basic principle of the measurement system is to illuminate the plate with a defined light source (LED) in a closed environment and to record the image with a CCD-camera system.

[0326] 2. Image analysis:

[0327] The sample is illuminated from one side with floodlight and the upwardly reflected part of the light is deflected by two mirrors to the CCD-sensor. The thus generated grey value image is analyzed on-line. From the deviation of the recorded grey values the mean square error (MSE) is calculated, which allows a quantification of the surface quality, i.e. the greater the MSE value, the more pronounced the surface defects.

[0328] Generally, for the same material, the tendency to flow marks increases when the injection speed is increased.

[0329] For this evaluation, substrates (440 x 148 x 2.8 mm 3 ) with a grain VW K50 and a film gate of 1.4 mm were used and these substrates were produced with different filling times of 1.5, 3 and 6 seconds, respectively.

[0330] Further conditions:

[0331] Melt temperature: 240 °C

[0332] Mold temperature 30 °C

[0333] Dynamic pressure: 10 bar hydraulic

[0334] The smaller the MSE value at a certain filling time, the smaller the tendency to flow marks.

[0335] The median particle size (D 50 ) and the top cut particle size (D 95 ) were calculated from the particle size distribution determined by laser diffraction according to ISO 13320-1 :1999.

[0336] 2. Examples

[0337] Preparation of HECO

[0338] Catalyst

[0339] First, 0.1 mole of MgCl2x 3 EtOH was suspended in 250 ml of decane in a reactor under inert conditions at atmospheric pressure. The solution was cooled to a temperature of -15°C and 300 ml of cold TiCl4was added while maintaining the temperature at this level. Then, the temperature of the slurry was slowly increased to 20°C. At this temperature, 0.02 mole of dioctyl phthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was increased to 135°C within 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl4was added and the temperature was maintained at 135°C for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml of heptane at 80°C. Then, the solid catalyst component was filtered and dried.

[0340] The catalyst and the concept of its preparation are generally described in, for example, patent publications EP 491566, EP 591224 and EP 586390.

[0341] The catalyst was further modified (VCH modification of the catalyst).

[0342] To a 125 ml stainless steel reactor, 35 ml of mineral oil (liquid paraffin PL68) was added at room temperature under inert conditions, followed by 0.82 g of triethylaluminium (TEAL) and 0.33 g of dicyclopentyl dimethoxysilane (donor D). After 10 minutes, 5.0 g of the catalyst prepared above (Ti content 1.4 wt%) was added and after a further 20 minutes, 5.0 g of vinyl cyclohexane (VCH) was added. The temperature was increased to 60°C within 30 minutes and maintained at this temperature for 20 hours. Finally, the temperature was decreased to 20°C and the concentration of unreacted VCH in the oil / catalyst mixture was analysed and found to be 200 ppm by weight.

[0343] Table 1: Polymerisation of HECO

[0344]

[0345]

[0346] In a twin-screw extruder, HECO was mixed with 1.00 wt% of Talc 3.1 (CAS No. 14807-96-6, supplied by IMI as Talc HM 2), 0.25 wt% of Dimodan HPL 80 / BB, 0.1 wt% of a blend of 67% tris(2,4-di-tert-butylphenyl)phosphite and 33% pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate] supplied by BASF AG (trade name Irganox B 215FF), and 0.05 wt% of calcium stearate (CAS No. 1592-23-0) supplied by Croda Polymer Additives.

[0347] Preparation of composition (C)

[0348] Example CE1 (comparative)

[0349] 56.7 wt% of HECO, 6.0 wt% of Borealis propylene homopolymer HL508FB, 20.0 wt% of Dow Engage XLT ethylene-octene copolymer, 13.0 wt% of talc (Imerys Jetfine 3CA), 3.0 wt% of a masterbatch of 70 wt% linear density polyethylene (LDPE) and 30 wt% of carbon black, 0.3 wt% of Cytec UV stabilizer masterbatch Cyasorb UV-3808PP5, 0.1 wt% of pentaerythritol tetrakis (3-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate (Songwon Songnox 1010FF), 0.1 wt% of tris (2,4-di-tert-butylphenyl) phosphite (HPL Additives' Kinox-68-G), 0.3 wt% of Croda's oleamide-9-octadecenamide, 0.2 wt% of Danisco's antistatic agent Dimodan HP FF, and 0.3 wt% of Faci's calcium stearate were melt blended on a co-rotating twin-screw extruder. The polymer melt mixture was discharged and pelletized.

[0350] Example IE1 (present invention)

[0351] In the main hopper of a twin-screw extruder Mega Compounder ZSK 18 (screw length 40D) with a temperature profile of 20 / 190 / 220 / 225 / 230 / 230 / 210 / 200 °C and a screw speed of 300 rpm, to a mixture of 56.5 wt% HECO, 6.0 wt% of a propylene homopolymer HL508FB by Borealis and 20.0 wt% of an ethylene-octene copolymer Engage XLT by Dow, 0.2 wt% of a 5 wt% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in polypropylene masterbatch was dosed. The polymer melt mixture was melt blended with 13.0 wt% of a talcum (Jetfine 3CA by Imerys), 3.0 wt% of a masterbatch of 70 wt% of a linear density polyethylene (LDPE) and 30 wt% of carbon black, 0.3 wt% of a UV stabilizer masterbatch Cyasorb UV-3808PP5 by Cytec, 0.1 wt% of pentaerythrityl tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)-propionate (Songnox 1010FF by Songwon), 0.1 wt% of tris(2,4-di-tert-butylphenyl)phosphite (Kinox-68-G by HPL Additives), 0.3 wt% of oleic acid amide 9-octadecenyl amide by Croda, 0.2 wt% of an antistatic agent Dimodan HP FF by Danisco and 0.3 wt% of calcium stearate by Faci on a co-rotating twin-screw extruder, discharged and pelletized.

[0352] Example IE2 (inventive)

[0353] IE2 was prepared analogously to IE1, except that 56.3 wt% of HECO and 0.4 wt% of a 5 wt% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in polypropylene masterbatch were employed.

[0354] Example CE2 (comparative)

[0355] CE2 was prepared analogously to CE1, except that an ethylene-octene copolymer Queo2M137 by Borealis was employed instead of Engage XLT by Dow.

[0356] Example IE3 (inventive)

[0357] IE3 was prepared analogously to IE1, except that an ethylene-octene copolymer Queo2M137 by Borealis was employed instead of Engage XLT by Dow.

[0358] Example IE4 (inventive)

[0359] IE4 was prepared analogously to IE1, except that 56.3 wt% HECO and 0.4 wt% of a 5 wt% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in polypropylene masterbatch were employed, and Borealis' ethylene-octene copolymer Queo 2M137 was employed instead of Dow's Engage XLT.

[0360] Example CE3 (comparative)

[0361] CE3 was prepared analogously to CE1, except that Borealis' ethylene-octene copolymer Queo 2M138 was employed instead of Dow's Engage XLT.

[0362] Example IE5 (inventive)

[0363] IE5 was prepared analogously to IE1, except that 56.3 wt% HECO and 0.4 wt% of a 5 wt% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in polypropylene masterbatch were employed, and Borealis' ethylene-octene copolymer Queo 2M138 was employed instead of Dow's Engage XLT.

[0364] Example CE4 (comparative)

[0365] CE4 was prepared analogously to CE1, except that 64.0 wt% HECO, 19.0 wt% of Dow's ethylene-butene copolymer Engage 7487HM (instead of Dow's Engage XLT), and 3.0 wt% pigment were employed. According to CE4, Borealis' propylene homopolymer HL508FB was not employed.

[0366] Example IE6 (inventive)

[0367] IE6 was prepared analogously to IE1, except that 63.6 wt% HECO, 19.0 wt% of Dow's ethylene-butene copolymer Engage 7487HM (instead of Dow's Engage XLT), 0.6 wt% of a 5 wt% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in polypropylene masterbatch, and 4.2 wt% pigment were employed. According to IE6, Borealis' propylene homopolymer HL508FB was not employed.

[0368] Table 2: Compositions of comparative and inventive examples

[0369] CE1 IE1 IE2 CE2 IE3 IE4 CE3 IE5 CE4 IE6 HECO [wt%] 56.7 56.5 56.3 56.7 56.5 56.3 56.7 56.3 64.0 63.4 HPP [wt%] 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 - - PL1 [wt%] 20.0 20.0 20.0 - - - - - - - PL2 [wt%] - - - 20.0 20.0 20.0 - - - - PL3 [wt%] - - - - - - 20.0 20.0 - - PL4 [wt%] - - - - - - - - 19.0 19.0 Talc [wt%] 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 Pigment [wt%] 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 AD [wt%] 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 POXPP [wt%] - 0.2 0.4 - 0.2 0.4 - 0.4 - 0.60

[0370] HPP is a commercially available propylene homopolymer HL508FB of Borealis having a melt flow rate MFR2(230 °C) of 800 g / 10 min.

[0371] PL1 is a commercially available ethylene-octene copolymer Engage XLT of Dow having a density of 0.875 g / cm3, a melt flow rate MFR2(190 °C) of 0.5 g / 10 min and a 1-octene content of 14.5 mol%. 3

[0372] PL2 is a commercially available ethylene-octene copolymer Queo 2M137 of Borealis having a density of 0.870 g / cm3, a melt flow rate MFR2(190 °C) of 1.0 g / 10 min and a 1-octene content of 9.9 mol%. 3

[0373] PL3 is a commercially available ethylene-octene copolymer Queo 2M138 of Borealis having a density of 0.868 g / cm3, a melt flow rate MFR2(190 °C) of 0.5 g / 10 min and a 1-octene content of 11.0 mol%. 3

[0374] PL4 is a commercially available ethylene-butene copolymer Engage HM 7487 of Dow having a density of 0.860 g / cm3, a melt flow rate MFR2(190 °C) of 0.5 g / 10 min and a 1-butene content of 19.1 mol%. 3

[0375] Talc is a commercially available talc Jetfine 3CA of Imerys having a d50(Sedigraph 5100) of 1.0 pm and a d95(Sedigraph 5100) of 3.3 pm.

[0376] Pigment is a masterbatch of 70 wt% linear density polyethylene (LDPE) and 30 wt% carbon black having a MFR (190 °C / 21.6 kg) of 15 g / 10 min.

[0377] ​​​​AD 0.3 wt% of Cytec's UV stabilizer masterbatch Cyasorb UV-3808PP5, 0.1 wt% of pentaerythrityl-tetrakis(3-(3',5'-di-tert-butyl-4- hydroxyphenyl)-propionate) (Songwon's Songnox 1010FF), 0.1 wt% of tris(2,4-di-tert- butylphenyl)phosphite (HPL Additives' Kinox-68-G), 0.3 wt% of oleic acid amide 9- octadecenamide of Croda, 0.2 wt% of antistatic agent Dimodan HP FF of Danisco and 0.3 wt% of calcium stearate of Faci.

[0378] POX PP is a 5 wt% masterbatch of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane with polypropylene.

[0379]

Claims

1. A composition (C) comprising a modified polypropylene composition (mPP) and an inorganic filler (F), wherein the modified polypropylene composition (mPP) is obtained by treating a polypropylene composition (PP) with a peroxide (PO), the polypropylene composition (PP) comprising (a) a heterophasic composition (HECO) comprising (a1) (semi)crystalline polypropylene (PP1), and (a2) an elastomeric ethylene / propylene copolymer (EPR) dispersed in the (semi)crystalline polypropylene (PP1), (b) a plastomer (PL) that is ethylene and at least one C4to C 20 copolymer of an α-olefin, and (c) optionally a high flow polypropylene (HPP), the high flow polypropylene (HPP) preferably having a higher melt flow rate MFR2(230 °C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1), wherein the modified polypropylene composition (mPP) has (i) a melt flow rate MFR2(230 °C) measured according to ISO 1133 higher than 32 g / 10 min, and (ii) an intrinsic viscosity IV of the xylene soluble fraction XCS determined according to DIN ISO 1628 / 1 (in decaline at 135 °C) lower than 2.30 d l / g, and (iii) an intrinsic viscosity IV of the xylene insoluble fraction XCI determined according to DIN ISO 1628 / 1 (in decaline at 135 °C) lower than 1.05 d l / g.

2. The composition (C) according to claim 1, wherein the plastomer (PL) is a copolymer of ethylene and 1-butene or 1-octene.

3. The composition (C) according to any of the preceding claims, wherein the weight ratio [(HECO) / (PL)] of the heterophasic composition (HECO) and the plastomer (PL) in the polypropylene composition (PP) is in the range of 0.1 to 10.

0.

4. The composition (C) according to any of the preceding claims, wherein the polypropylene composition (PP) comprises 3 to 15 wt.-% of the high flow polypropylene (HPP) based on the total weight of the polypropylene composition (PP), the high flow polypropylene (HPP) preferably having a higher melt flow rate MFR2(230 °C) measured according to ISO 1133 than the (semi)crystalline polypropylene (PP1).

5. The composition (C) according to any of the preceding claims, comprising based on the total weight of the composition (C) (a) 45 to 95 wt.-% of the modified polypropylene composition (mPP), and (b) 5 to 30 wt.-% of the inorganic filler (F).

6. The composition (C) according to any of the preceding claims, wherein the heterophasic composition (HECO) has (a) a comonomer content in the range of 3 to 20 wt.-% based on the total weight of the heterophasic composition (HECO), and / or (b) a xylene soluble fraction (XCS) in the range of 10 to 35 wt.-%, and / or (c) a melt flow rate MFR2(230 °C) measured according to ISO 1133 of 40 to 100 g / 10 min.

7. The composition (C) according to any one of the preceding claims, wherein the xylene soluble fraction (XCS) of the heterophasic composition (HECO) has (a) an intrinsic viscosity (IV) determined according to DIN ISO 1628 / 1 (in decalin at 135 °C) in the range of 1.5 to 4.5 dl / g, and (b) a comonomer content in the range of 25 to 55 wt.-%, based on the total weight of the xylene soluble fraction (XCS) of the heterophasic composition (HECO).

8. The composition (C) according to any one of the preceding claims, wherein the plastomer (P) has (a) a melt flow rate MFR (190 °C) measured according to ISO 1133 of 0.05 to 5.0 g / 10 min, (b) a comonomer content in the range of 5 to 25 mol-%, based on the total weight of the plastomer (PL), and (c) a density equal to or lower than 0.880 g / cm 3 of density.

9. The composition (C) according to any one of the preceding claims, wherein the inorganic filler (F) is talc.

10. An article comprising the composition (C) according to any one of the preceding claims 1 to 9, preferably an injection molded automotive article.

11. Use of a peroxide (PO) for reducing tiger stripes of a polypropylene composition (PP) according to any one of the preceding claims, wherein the composition (C) according to any one of the preceding claims 1 to 6 is obtained.

12. The use according to claim 11, wherein the reduction of tiger stripes is achieved in case the MSE value is equal to or below 30.

13. A process for preparing the composition (C) according to any one of claims 1 to 9, wherein (a) (a1) extruding a polypropylene composition (PP) comprising a heterophasic composition (HECO), a plastomer (PL) and optionally a high flow polypropylene (HPP) in the presence of a peroxide (PO) in an extruder, thereby obtaining a modified polypropylene composition (mPP), and (b1) melt blending the modified polypropylene composition (mPP) with an inorganic filler (F), or (b) extruding a polypropylene composition (PP) comprising a heterophasic composition (HECO), a plastomer (PL), optionally a high flow polypropylene (HPP) and an inorganic filler (F) in the presence of a peroxide (PO) in an extruder.

14. The use according to claim 11 or 12, wherein the polypropylene composition (PP) is a heterophasic composition (HECO) according to any one of claims 1 to 6.

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