Polyolefin composition with excellent balance of properties

Abstract

The present invention relates to a polyolefin composition having an excellent balance between low temperature impact, stiffness and transparency. The polyolefin composition comprises comonomer units derived from propylene, ethylene and 1-butene, and is characterized by a high content of a xylene insoluble component (XI) and a low content of a xylene soluble component (XS) having a specific intrinsic viscosity IV. The polyolefin composition is preferably prepared from a heterophasic polypropylene composition and an ethylene homopolymer. The heterophasic polypropylene composition comprises a propylene butene copolymer and a propylene ethylene elastomer, and is prepared using a Ziegler-Natta catalyst. In addition, the invention also relates to a preparation method of the polyolefin composition, an article comprising the polyolefin composition, and application of the polyolefin composition in manufacturing of the article.

Description

Technical Field

[0001] The present invention relates to a polyolefin composition having an excellent balance between low-temperature impact, stiffness and transparency. The xylene-insoluble component (XI) and the polyolefin composition of relatively low content comprise comonomer units derived from propylene, ethylene and 1-butene, characterized in that the higher content has a xylene-soluble component (XS) with a specific intrinsic viscosity IV. The polyolefin composition is preferably prepared by a heterophasic polypropylene composition and an ethylene homopolymer. The heterophasic polypropylene composition comprises a propylene-butene copolymer and a propylene-ethylene elastomer and is prepared using a Ziegler-Natta catalyst. In addition, the present invention further relates to a method for preparing the polyolefin composition, and relates to articles comprising the polyolefin composition and relates to the purposes of the polyolefin composition in the manufacture of articles. Background Art

[0002] Polypropylene is widely used in film and molding applications, including caps and seals, thin-wall packaging, household goods, and similar applications. High stiffness and good impact strength are desirable in these applications. Balanced optical properties are also often important, such as clarity in food packaging.

[0003] Heterogeneous propylene copolymers are often used in such packaging applications because of their excellent balance of properties. Usually, these are copolymers of propylene and ethene. However, heterogeneous propylene polymers with other comonomers are also known in packaging applications. For example, EP-A-3126411 describes a heterogeneous propylene copolymer comprising propylene-C4 to C4 as a matrix. 12 The invention relates to a multiphase propylene polymer comprising an α-olefin and a propylene-ethylene elastomer as a dispersed phase. The multiphase propylene polymer is prepared using a single-site solid particle catalyst. Although some exemplary polymers have acceptable impact strength, their other mechanical properties (such as stiffness) may still need further improvement.

[0004] Furthermore, in heterophasic propylene polymers, optical properties are often compromised due to the different refractive indices of the dispersed rubber phase, which can lead to light scattering, resulting in opaque materials.

[0005] To meet the diverse requirements of packaging applications, a balance of mechanical properties, including stiffness and impact strength, is required. Polymers with higher stiffness can allow for the use of lower film thicknesses, saving both material and energy. Good impact resistance is also crucial, ensuring that the contents are safely contained even if the package is dropped. In particular, good impact resistance at low temperatures is important for packaging frozen goods. Polymers with good optical properties, such as low haze, are important in applications where consumers can see through the package to the contents of the packaged product. Summary of the Invention

[0006] Purpose of the Invention

[0007] It is therefore an object of the present invention to provide novel polyolefin compositions which can provide an improved balance of stiffness and impact strength combined with good optical properties. In particular, polyolefin compositions for applications in the packaging sector, such as molded articles or films are desired. SUMMARY OF THE INVENTION

[0009] Surprisingly, it has been found that the above objects can be achieved by a polyolefin composition comprising:

[0010] I) 55 to 95 wt.-% of a xylene insoluble fraction (XI), based on the total weight of the polyolefin composition and determined according to ISO 16152 at 25° C., said xylene insoluble fraction (XI) comprising comonomer units derived from propylene, comonomer units derived from ethylene in an amount in the range of 5.0 to 40.0 wt.-% and comonomer units derived from 1-butene in an amount in the range of 1.0 to 10.0 wt.-%, and

[0011] II) 5 to 45 wt.-% of a xylene soluble fraction (XS), based on the total weight of the polyolefin composition and measured at 25° C. according to ISO 16152, said xylene soluble fraction (XS) comprising comonomer units derived from propylene, comonomer units derived from ethylene in an amount in the range of 20.0 to 60.0 wt.-% and optionally comonomer units derived from 1-butene, and said xylene soluble fraction (XS) having an intrinsic viscosity IV in the range of 1.2 to 3.0 dl / g, measured according to ISO 1628-1 and 3; and

[0012] wherein the polyolefin composition has at least two melting temperatures, a first melting temperature T m1 In the range of 150°C to 167°C, and the second melting temperature T m2 in the range of 90°C to 125°C; and

[0013] The melt flow rate MFR2 (230° C.), determined according to ISO 1133, is in the range of 20 to 80 g / 10 min.

[0014] Furthermore, it has been found that the above objects are achieved by a process for the preparation of a polyolefin composition according to the present invention, wherein the process comprises preparing a heterophasic polypropylene composition by a multistage polymerization process and blending the heterophasic polypropylene composition with an ethylene homopolymer (C) to obtain the polyolefin composition.

[0015] It has also been found that the above objects can be achieved by an article, preferably a film or a molded article, comprising the polyolefin composition, and by the use of the polyolefin composition for the production of corresponding articles. Detailed Description of the Invention

[0017] The present invention relates to a polyolefin composition comprising: a xylene-insoluble fraction (XI) comprising comonomer units derived from propylene, ethylene and 1-butene, and a xylene-soluble fraction (XS) comprising comonomer units derived from propane, ethylene and optionally 1-butene. The composition is preferably prepared from a heterophasic polypropylene composition and an ethylene homopolymer (C). The present invention also relates to a process for preparing the polyolefin composition.

[0018] Polyolefin composition

[0019] The term "polyolefin composition" generally describes a composition comprising at least one polyolefin polymer. The term "polyolefin polymer" refers to a polymer comprising or consisting of monomeric units selected from ethylene, propylene, and α-olefin units containing from 4 to 12 carbon atoms.

[0020] The expression "α-olefin" units (such as propylene, ethylene, 1-butene units, etc.) used herein to refer to the content of a polymer should be understood to teach that these units are used to prepare the polymer. The resulting polymer contains the corresponding units derived from these α-olefin monomer units.

[0021] Therefore can comprise these polymkeric substance by being prepared by heterophasic polypropylene composition and ethylene homopolymer (C) according to polyolefin composition of the present invention.In one embodiment, described polyolefin composition comprises heterophasic polypropylene composition and ethylene homopolymer (C) at least.Described polyolefin composition can comprise other components, for example other polyolefin or non-polyolefin polymer.Preferably, described polyolefin composition does not comprise non-polyolefin polymer.

[0022] According to the present invention, the polyolefin composition comprises from 55 wt.-% to 95 wt.-%, preferably from 70 wt.-% to 93 wt.-%, more preferably from 75 wt.-% to 90 wt.-% of a xylene-insoluble fraction (XI), based on the total weight of the polyolefin composition and measured according to ISO 16152 at 25°C, and from 5 wt.-% to 45 wt.-%, preferably from 7 wt.-% to 30 wt.-%, more preferably from 10 wt.-% to 25 wt.-% of a xylene soluble fraction (XS), based on the total weight of the polyolefin composition and measured according to ISO 16152 at 25°C.

[0023] The 1-butene content of the xylene insoluble fraction (XI) of the polyolefin composition is in the range of 1.0 to 10.0 wt.-%, preferably 1.1 to 8.0 wt.-%, and more preferably 1.2 to 5.0 wt.-%.

[0024] The ethylene content of the xylene insoluble fraction (XI) of the polyolefin composition is in the range of 5.0 to 40.0 wt.-%, more preferably 8.0 to 35.0 wt.-%, and even more preferably 10.0 to 30.0 wt.-%. All amounts are based on the total weight of the xylene insoluble fraction (XI).

[0025] The 1-butene content of the xylene soluble fraction (XS) of the polyolefin composition is preferably in the range of 0 to 3.0 wt.-%. If 1-butene is present, its content is preferably in the range of 0.1 to 3.0 wt.-%, more preferably 0.3 to 2.5 wt.-%, and even more preferably 0.5 to 2.0 wt.-%. In a preferred embodiment, 1-butene is absent from the xylene soluble fraction (XS) of the polyolefin composition.

[0026] The ethylene content of the xylene soluble fraction (XS) of the polyolefin composition is preferably in the range of 20 to 60 wt.-%, more preferably 22 to 50 wt.-%, and even more preferably 25 to 45 wt.-%. All amounts are based on the total weight of the xylene soluble fraction (XS).

[0027] The comonomer content of the polyolefin composition, the xylene soluble fraction (XS) and the xylene insoluble fraction (XI) is determined based on NMR spectroscopy as described herein in the methods section.

[0028] The xylene soluble fraction (XS) has an intrinsic viscosity IV, determined according to ISO 1628-1 & 3, in the range of 1.2 to 3.0 dl / g, preferably 1.3 to 2.7 dl / g, more preferably 1.4 to 2.5 dl / g, and even more preferably 1.7 to 2.1 dl / g.

[0029] The polyolefin composition comprises at least propylene, 1-butene and ethylene comonomer units, i.e. at least a terpolymer composition. The 1-butene content in the polyolefin composition is preferably in the range of 0.5 wt.-% to 5.0 wt.-%, more preferably 0.6 wt.-% to 4.5 wt.-%, and even more preferably 0.7 wt.-% to 4.0 wt.-%. The ethylene content in the polyolefin composition is preferably in the range of 10.0 wt.-% to 40.0 wt.-%, more preferably 12.0 wt.-% to 35.0 wt.-%, and even more preferably 15.0 wt.-% to 30.0 wt.-%. All contents are based on the gross weight of the polyolefin composition.

[0030] In a preferred embodiment, the xylene insoluble fraction (XI) comprises a propylene copolymer (A) of propylene with 1-butene comonomer units in an amount in the range of 1.0 to 10.0 wt.% and optionally ethylene comonomer units in an amount in the range of 0 to 6.0 wt.%. Preferably, the propylene copolymer (A) has a melt flow rate MFR2 (230°C) in the range of 30 to 400 g / 10 min, determined according to ISO 1133. The propylene copolymer (A) is preferably produced using a Ziegler-Natta catalyst.

[0031] The xylene insoluble fraction (XI) preferably also comprises an ethylene homopolymer (C). Preferably, the ethylene homopolymer (C) has a melt flow rate MFR2 (190° C.) in the range of 4 g / 10 min to 100 g / 10 min, measured according to ISO 1133, and a melt flow rate MFR2 (190° C.) in the range of 910 kg / m2, measured according to ISO 1183. 3 Up to 940kg / m 3 Density within the range.

[0032] The xylene soluble fraction (XS) preferably comprises the propylene ethylene elastomer (B) having an ethylene content in the range of 20 to 60 wt.-% and optionally comprises 1-butene comonomer units.The propylene ethylene elastomer (B) is preferably prepared using a Ziegler-Natta catalyst.

[0033] Embodiments of polymer (A), polymer (B), and polymer (C) are described in detail below.

[0034] The polyolefin composition may be prepared from a heterophasic polypropylene composition comprising a propylene copolymer (A) and a propylene ethylene elastomer (B) and an ethylene homopolymer (C).

[0035] In a preferred embodiment the polyolefin composition comprises the heterophasic polypropylene composition according to any of the embodiments described below and an ethylene homopolymer (C).

[0036] The polyolefin composition preferably comprises from 75 wt.-% to 95 wt.-%, preferably from 80 wt.-% to 90 wt.-% of the heterophasic polypropylene composition and from 5 wt.-% to 25 wt.-%, more preferably from 10 wt.-% to 20 wt.-% of the ethylene homopolymer (C), based on the total weight of the polyolefin composition. In a specific embodiment, the polyolefin composition consists of the determined amounts of these two components and further optional polymer additives, preferably in the range of up to 5 wt.-%, based on the total weight of the polyolefin composition.

[0037] Unless stated otherwise, percentages in the present disclosure are percentages by weight (wt.-%) based on the total weight of the respective enclosed entity.

[0038] In a preferred embodiment, the polyolefin composition is a blend of a heterophasic polypropylene composition and an ethylene homopolymer (C), preferably a blend having the above determined contents. Blending can be performed by any method known in the art for polymer blending.

[0039] The polyolefin composition has medium to high fluidity. The polyolefin composition has a melt flow rate MFR2 (230°C) in the range of 20 to 80 g / 10 min, preferably 25 to 70 g / 10 min, and more preferably 30 to 60 g / 10 min, measured according to ISO 1133.

[0040] The polyolefin composition has at least two melting temperatures, namely a first melting temperature T m1 and the second melting temperature T m2 The first melting temperature T m1 In the range of 150° C. to 167° C., preferably 155° C. to 166° C., and more preferably 156° C. to 165° C. The corresponding first melting enthalpy H m1 It is preferably in the range of 60 J / g to 95 J / g, more preferably 63 J / g to 90 J / g, and even more preferably 65 J / g to 85 J / g.

[0041] The second melting temperature T m2 In the range of 90° C. to 125° C., preferably 93° C. to 120° C., and more preferably 95° C. to 110° C. The corresponding second melting enthalpy H m2 It is preferably in the range of 5 J / g to 50 J / g, more preferably 10 J / g to 40 J / g, and even more preferably 15 J / g to 35 J / g.

[0042] Melting temperature and melting enthalpy are determined according to Differential Scanning Calorimetry (DSC) as described herein. In the present disclosure, melting temperature is understood to be the temperature peak obtained from the DSC analysis.

[0043] Preferably, the polyolefin composition has a crystallization temperature Tc, determined according to differential scanning calorimetry (DSC) as described herein, in the range of 105 to 140° C., more preferably 110 to 138° C. and even more preferably 115 to 135° C. The crystallization temperature Tc is preferably at least 105° C. and / or at most 140° C.

[0044] Polyolefin composition has excellent rigidity.Preferably, measure according to ISO178, polyolefin composition has the flexural modulus greater than 950MPa, and preferably in the scope of greater than 950MPa to 1500MPa, more preferably 970MPa to 1450MPa, even more preferably 1000MPa to 1400MPa.Described flexural modulus is preferably at least greater than 950MPa and / or 1500MPa at the most.

[0045] The polyolefin composition has excellent impact properties. Preferably, the polyolefin composition has an impact strength of 4.0 kJ / m at +23°C, measured according to ISO 179 / 1eA. 2 Up to 15.0kJ / m 2 The impact strength is within the range of 4.5 kJ / m 2 Up to 14.0 kJ / m 2 , and even more preferably 5.0 kJ / m 2 Up to 12.0 kJ / m 2 The impact strength at +23°C is preferably at least 4.0 kJ / m 2 and / or up to 15.0 kJ / m 2 .

[0046] Preferably, the polyolefin composition has a relative humidity of 1.8 kJ / m at -20°C, measured according to ISO 179 / 1eA. 2 Up to 10.0 kJ / m 2 The impact strength is within the range of 1.9 kJ / m 2 Up to 9.0kJ / m 2 , and even more preferably 2.0 kJ / m 2 Up to 8.0kJ / m 2 The impact strength at -20°C is preferably at least 1.8 kJ / m 2 and / or up to 10.0 kJ / m 2 .

[0047] The polyolefin composition has good optical properties. According to ASTM1003 in 60×60×1mm3 The polyolefin composition preferably has a haze value of less than 70%, more preferably less than 68%, and even more preferably less than 65%, measured on a plate of . Preferably, the haze value is at least 30%.

[0048] The polyolefin composition preferably has a viscosity greater than 35 kJMPa / m at -20°C. 2 The photomechanical ability (OMA (-20 ° C)) is more than 40 kJMPa / m 2 , even more preferably greater than 45 kJMPa / m 2 Preferably, the polyolefin composition has a thermal conductivity of not more than 100 kJMPa / m at -20°C. 2 The photomechanical ability (OMA (-20 ° C)) of the invention is preferably not more than 90 kJMPa / m 2 The photo-mechanical capabilities were determined as described in the Methods section herein.

[0049] Heterophasic polypropylene composition

[0050] The polyolefin composition according to the present invention can be prepared from a heterophasic polypropylene composition and preferably comprises a heterophasic polypropylene blend. The heterophasic polypropylene composition preferably comprises or consists of a propylene copolymer (A) and a propylene ethylene elastomer (B).

[0051] The term "heterophasic polypropylene composition" as used herein refers to the presence of at least two different phases in the composition, i.e. the propylene copolymer (A) and the propylene ethylene elastomer (B). The propylene copolymer (A) forms the crystalline matrix of the heterophasic polypropylene composition, while the propylene ethylene elastomer (B) is dispersed in the crystalline matrix. The presence of the different phases can be easily detected by DSC analysis: the crystalline matrix propylene copolymer (A) will show a melting temperature that is higher than the melting temperature of the propylene ethylene elastomer (B).

[0052] The term "propylene copolymer" as used herein denotes a polymer comprising at least 50 wt.-% of propylene monomer units and other α-olefin comonomer units other than propylene, based on the total weight of the polymer.

[0053] The heterophasic polypropylene composition may comprise 55 to 90 wt.-%, preferably 60 to 90 wt.-% and more preferably 65 to 89 wt.-% of propylene copolymer (A), based on the total weight of the heterophasic polypropylene composition.

[0054] The heterophasic polypropylene composition may comprise 10 to 45 wt.-%, preferably 10 to 40 wt.-% and more preferably 11 to 35 wt.-% of propylene ethylene elastomer (B), based on the total weight of the heterophasic polypropylene composition.

[0055] The heterophasic polypropylene composition may comprise 55 to 90 wt.-%, preferably 60 to 90 wt.-% and more preferably 65 to 89 wt.-% of a xylene insoluble fraction (XI), based on the total weight of the heterophasic polypropylene composition and determined according to ISO 16152 at 25 °C.

[0056] The heterophasic polypropylene composition may comprise 10 to 45 wt.-%, preferably 10 to 40 wt.-% and more preferably 11 to 35 wt.-% of a xylene soluble fraction (XS), based on the total weight of the heterophasic polypropylene composition and determined according to ISO 16152 at 25 °C.

[0057] Preferably, the xylene insoluble fraction (XI) of the heterophasic polypropylene composition comprises at least 80 wt.-%, more preferably at least 95 wt.-% and up to 100 wt.-% of propylene copolymer (A), based on the total weight of the xylene insoluble fraction (XI).

[0058] Preferably, the xylene soluble fraction (XS) of the heterophasic polypropylene composition comprises at least 80 wt.-%, more preferably at least 95 wt.-% and at most 100 wt.-% of propylene ethylene elastomer (B), based on the total weight of the xylene soluble fraction (XS).

[0059] The heterophasic polypropylene composition preferably has a melting temperature T 0 in the range of 150 to 167 °C, determined according to Differential Scanning Calorimetry (DSC) as described herein. m , preferably 155°C to 166°C, and more preferably 156°C to 165°C.

[0060] The heterophasic polypropylene composition can be obtained or obtainable by the polymerization process using a Ziegler-Natta catalyst. Preferably, the heterophasic polypropylene composition adopts the Ziegler-Natta catalyst production described in the preferred embodiment according to the preparation of the heterophasic polypropylene composition as described herein. Selected from propylene copolymer (A), the component (A1) of propylene copolymer (A) and a kind of (A2) and at least one polymer of propylene ethylene elastomer (B) are prepared under the presence of a Ziegler-Natta catalyst. Preferably, all of these polymers are prepared under the presence of a Ziegler-Natta catalyst.

[0061] The heterophasic polypropylene composition is at least a terpolymer comprising propylene and 1-butene and ethylene comonomer units. The 1-butene content in the heterophasic polypropylene composition is preferably in the range of 0.5 wt.-% to 5.0 wt.-%, more preferably 0.6 wt.-% to 4.5 wt.-%, and even more preferably 0.7 wt.-% to 4.0 wt.-%. The ethylene content in the heterophasic polypropylene composition is preferably in the range of 1.0 wt.-% to 20.0 wt.-%, more preferably 3.0 wt.-% to 15.0 wt.-%, and even more preferably 5.0 wt.-% to 13.0 wt.-%. All amounts are based on the total weight of the heterophasic polypropylene composition.

[0062] The 1-butene content of the xylene insoluble fraction (XI) of the heterophasic polypropylene composition is preferably in the range of 1.0 to 10.0 wt.-%, more preferably in the range of 1.2 to 8.0 wt.-%, and even more preferably in the range of 1.5 to 5.0 wt.-%. The ethylene content of the xylene insoluble fraction (XI) of the heterophasic polypropylene composition is preferably in the range of 0.1 to 6.0 wt.-%, more preferably in the range of 0.5 to 5.5 wt.-%, and even more preferably in the range of 1.0 to 5.0 wt.-%. All amounts are based on the total weight of the xylene insoluble fraction (XI).

[0063] The 1-butene content in the xylene soluble fraction (XS) of the heterophasic polypropylene composition is preferably in the range of 0 wt.-% to 5.0 wt.-%. If 1-butene is present, its content is preferably in the range of 0.1 wt.-% to 5.0 wt.-%, more preferably 0.5 wt.-% to 4.5 wt.-%, and even more preferably 1.0 wt.-% to 4.0 wt.-%. In a preferred embodiment, 1-butene is not present in the xylene soluble fraction (XS) of the heterophasic polypropylene composition. The ethylene content in the xylene soluble fraction (XS) of the heterophasic polypropylene composition is preferably in the range of 20 wt.-% to 60 wt.-%, more preferably 22 wt.-% to 50 wt.-%, and even more preferably 25 wt.-% to 45 wt.-%. All amounts are based on the total weight of the xylene soluble fraction (XS).

[0064] The comonomer content of the heterophasic polypropylene composition, the xylene soluble fraction (XS) and the xylene insoluble fraction (XI) as well as the propylene copolymer are determined based on NMR spectroscopy as described herein in the methods section.

[0065] Preferably, propylene, 1-butene and ethylene are the only comonomers present in the heterophasic polypropylene composition. Preferably, the heterophasic polypropylene composition is substantially free of units derived from other α-olefin monomers (i.e. C5 to C8 α-olefin monomers), e.g., it comprises less than 0.1 wt.-%, preferably less than 0.05 wt.-%, and more preferably less than 0.01 wt.-% of other α-olefin monomers, e.g., C5 to C8 α-olefin monomer units.

[0066] The xylene soluble fraction (XS) of the heterophasic polypropylene composition preferably has an intrinsic viscosity IV, determined according to ISO 1628-1 & 3, in the range of 1.2 to 3.0 dl / g, preferably 1.3 to 2.7 dl / g, more preferably 1.4 to 2.5 dl / g and even more preferably 1.7 to 2.1 dl / g.

[0067] Preferably, the propylene copolymer (A) and the propylene ethylene elastomer (B) are the only polymer components in the heterophasic polypropylene composition. However, it is understood herein that the heterophasic polypropylene composition may comprise other components, such as additives, which may optionally be added to the mixture with or without a carrier polymer (e.g. in a masterbatch).

[0068] Suitable additives include fillers, lubricants, processing aids, antioxidants, UV absorbers, light stabilizers, nucleating agents, foaming or blowing agents, clarifiers, and pigments.

[0069] The additives may be present in the heterophasic polypropylene composition in an amount ranging from 0.1 to 10.0 wt.-%, preferably from 0.3 to 5.0 wt.-%, more preferably from 0.5 to 3.0 wt.-%, based on the total weight of the heterophasic polypropylene composition.

[0070] Propylene copolymer (A)

[0071] The propylene copolymer (A) is a copolymer of propylene and 1-butene as a comonomer. The content of 1-butene comonomer units in the propylene copolymer (A) is preferably in the range of 1.0 wt.-% to 10.0 wt.-%, preferably 1.2 wt.-% to 8.0 wt.-%, and more preferably 1.5 wt.-% to 5.0 wt.-%.

[0072] The propylene copolymer (A) may contain ethylene as an additional comonomer. The content of ethylene comonomer units in the propylene copolymer (A) is preferably in the range of 0 wt.-% to 6.0 wt.-%. If ethylene is present, its content is preferably in the range of 0.1 wt.-% to 6.0 wt.-%, more preferably 0.5 wt.-% to 5.5 wt.-%, and even more preferably 1.0 wt.-% to 5.0 wt.-%.

[0073] Preferably, propylene, 1-butene and optionally ethylene are the only comonomers present in the propylene copolymer (A). Preferably, the propylene copolymer (A) is essentially free of units derived from other α-olefin monomers, i.e. C5 to C8 α-olefin units, e.g. it comprises other α-olefin monomers, such as C5 to C8 α-olefin monomer units, in an amount of less than 0.1 wt.-%, preferably less than 0.05 wt.-% and more preferably less than 0.01 wt.-%.

[0074] The propylene copolymer (A) is preferably obtainable or has been obtained by a polymerization process using a Ziegler-Natta catalyst. Preferably, the propylene copolymer (A) is produced using a Ziegler-Natta catalyst according to the preferred embodiments described herein for the preparation of the heterophasic polypropylene composition.

[0075] The propylene copolymer (A) preferably has a melt flow rate MFR2 (230°C), determined according to ISO 1133, in the range of 30 to 400 g / 10 min, preferably 40 to 300 g / 10 min and more preferably 50 to 200 g / 10 min.

[0076] The propylene copolymer (A) composition preferably has a melting temperature T 0 ... m Within the range of 150°C to 167°C, preferably 155°C to 166°C, and more preferably 156°C to 165°C.

[0077] Preferably, the propylene copolymer (A) has a molecular weight distribution M w / M n (i.e. weight average molecular weight M w and number average molecular weight M n ) is in the range of 3.0 to 20.0, more preferably 4.0 to 15.0, and most preferably 5.5 to 9.0.

[0078] Preferably, the propylene copolymer (A) has a xylene soluble fraction (XS) in the range of 1.0 to 8.0 wt.-%, more preferably 1.2 to 7.5 wt.-% and even more preferably 1.5 to 7.0 wt.-%, determined at 25°C according to ISO 16152. The amount of xylene soluble fraction (XS) is preferably at most 8.0 wt.-% of the propylene copolymer (A).

[0079] The propylene copolymer (A) is preferably a multimodal polymer. The term "multimodal polymer" as used herein refers to a polymer composition comprising at least two polymer fractions produced under different polymerization conditions, resulting in different (weight average) molecular weights and / or molecular weight distributions and / or different comonomer contents for the fractions. The prefix "multi" relates to the number of different polymer fractions comprising the polymer. The term "multimodal polymer" includes bimodal, trimodal, quadromodal, etc. polymers.

[0080] More preferably the propylene copolymer (A) is a bimodal polymer, i.e. it consists of two different polymer fractions, e.g. a first propylene polymer fraction (A1) and a second propylene polymer fraction (A2), each comprising a propylene polymer. The two fractions are different from each other.

[0081] In a specific embodiment, the propylene copolymer (A) comprises or consists of a first propylene polymer component (A1) which is a propylene homopolymer or a propylene copolymer of propylene with 1-butene comonomer units and / or ethylene comonomer units, preferably a propylene homopolymer or a propylene copolymer having less than 1 wt.-% comonomer units, based on the total weight of the first propylene polymer component (A1); and a second propylene polymer component (A2) which is a propylene copolymer of propylene with 1-butene comonomer units and optionally ethylene comonomer units. Embodiments of the first propylene polymer component (A1) and the second propylene polymer component (A2) are described below.

[0082] Preferably, the propylene copolymer (A) comprises or consists of 25 to 75 wt.-% of the first propylene polymer fraction (A1 ), based on the total weight of the propylene copolymer (A); and 75 to 25 wt.-% of the second propylene polymer fraction (A2), based on the total weight of the propylene copolymer (A).

[0083] In other words, the weight ratio of the first propylene polymer component (A1) to the second propylene polymer component (A2) in the propylene copolymer (A) is preferably in the range of 25:75 to 75:25, more preferably in the range of 30:70 to 70:30, most preferably 35:65 to 65:35.

[0084] First propylene polymer component (A1)

[0085] The first propylene polymer component (A1) is preferably composed of a single propylene polymer. The propylene polymer of the first propylene polymer component (A1) can be a propylene homopolymer or a propylene copolymer. If the propylene polymer of the first propylene polymer component (A1) is a propylene copolymer, then it is a copolymer of propylene and 1-butene comonomer units and / or ethylene comonomer units, preferably a copolymer of ethylene comonomer units. In a preferred embodiment, the propylene polymer of the first propylene polymer component (A1) is a propylene homopolymer or has a propylene copolymer of less than 1 wt.-% comonomer units based on the first propylene polymer component (A1) gross weight.

[0086] The first propylene copolymer fraction (A1) is preferably obtainable or has been obtained by a polymerization process using a Ziegler-Natta catalyst. Preferably, the first propylene copolymer fraction (A1) is produced using a Ziegler-Natta catalyst according to the preferred embodiments described herein for the preparation of the heterophasic polypropylene composition.

[0087] Preferably, the first propylene copolymer fraction (A1 ) has a melt flow rate MFR2 (230°C), determined according to ISO 1133, in the range of 30 to 400 g / 10 min, more preferably 40 to 300 g / 10 min and even more preferably 50 to 200 g / 10 min.

[0088] Preferably, the first propylene copolymer fraction (A1) has a xylene soluble fraction (XS) in the range of 1.0 to 8.0 wt.-%, more preferably 1.2 to 7.5 wt.-%, and even more preferably 1.5 to 7.0 wt.-%, determined at 25°C according to ISO 16152. The amount of xylene soluble fraction (XS) is preferably at most 8.0 wt.-% of the first propylene copolymer fraction (A1).

[0089] Preferably, the first propylene polymer fraction (A1 ) is present in the propylene copolymer (A) in an amount of 25 to 75 wt.-%, preferably 30 to 70 wt.-% and more preferably 35 to 65 wt.-%, based on the total weight of the propylene copolymer (A).

[0090] Second propylene polymer component (A2)

[0091] The second propylene polymer fraction (A2) is different from the first propylene polymer fraction (A1 ).The second propylene polymer fraction (A2) may be different from the first propylene polymer fraction (A1 ) in the amount and / or quality of the comonomers.

[0092] The second propylene polymer component (A2) is preferably composed of a single propylene polymer. The propylene polymer of the second propylene polymer component (A2) is preferably a propylene copolymer of propylene and 1-butene comonomer units and optional ethylene comonomer units. In a particularly preferred embodiment, the propylene polymer of the second propylene polymer component (A2) is a propylene copolymer of propylene and 1-butene comonomer units. In another specific embodiment, the propylene polymer of the second propylene polymer component (A2) is a propylene copolymer of propylene and 1-butene comonomer units and ethylene comonomer units.

[0093] The second propylene polymer component (A2) can be produced in the presence of the aforementioned first polymer component (A1) to form the propylene copolymer (A). If so, the properties of the second propylene polymer component (A2) cannot be determined directly, but are calculated based on the values ​​of the propylene copolymer (A) and the first polymer component (A1).

[0094] The content of 1-butene comonomer units in the second propylene polymer fraction (A2) is preferably in the range of 2.0 to 15.0 wt.-%, preferably 3.0 to 13.0 wt.-% and more preferably 4.0 to 11.0 wt.-%.

[0095] The second propylene polymer fraction (A2) is preferably obtainable or has been obtained by a polymerization process using a Ziegler-Natta catalyst. Preferably, the second propylene polymer fraction (A2) is produced using a Ziegler-Natta catalyst according to the preferred embodiments described herein for the preparation of the heterophasic polypropylene composition.

[0096] Preferably, the second propylene polymer component (A2) has a melt flow rate MFR2 (230°C), determined according to ISO 1133, in the range of 30 to 400 g / 10 min, more preferably 40 to 300 g / 10 min, and even more preferably 50 to 200 g / 10 min.

[0097] As described herein for the preparation of the heterophasic polypropylene composition the MFR2 of the second propylene polymer fraction (A2) is determined according to formula (1).

[0098] Preferably, the second propylene polymer component (A2) has a xylene soluble fraction (XS) in the range of 1.0 to 8.0 wt.-%, more preferably 1.2 to 7.5 wt.-%, and even more preferably 1.5 to 7.0 wt.-%, determined at 25°C according to ISO 16152. The amount of xylene soluble fraction (XS) is preferably at most 8.0 wt.-% of the second propylene polymer component (A2).

[0099] As described herein for the preparation of the heterophasic polypropylene composition the xylene soluble fraction (XS) of the second propylene polymer fraction (A2) is determined according to formula (2).

[0100] Preferably, the second propylene polymer fraction (A2) is present in the propylene copolymer (A) in an amount of 25 to 75 wt.-%, preferably 30 to 70 wt.-% and more preferably 35 to 65 wt.-%, based on the total weight of the propylene copolymer (A).

[0101] Propylene ethylene elastomer (B)

[0102] Propylene ethylene elastomer (B) is a copolymer of propylene and ethylene. Based on the gross weight of propylene ethylene elastomer (B), the ethylene content in propylene ethylene elastomer (B) is in the range of 20wt.-% to 60wt.-%, more preferably 22wt.-% to 50wt.-%, even more preferably 25wt.-% to 45wt.-%. As described in the methods section, the ethylene content is measured by NMR spectroscopy.

[0103] The propylene ethylene elastomer (B) may contain 1-butene comonomer units. The content of 1-butene comonomer units in the propylene ethylene elastomer (B) is preferably in the range of 0 wt.-% to 5.0 wt.-%. If 1-butene is present, its content is preferably in the range of 0.1 wt.-% to 5.0 wt.-%, more preferably 0.5 wt.-% to 4.5 wt.-%, and even more preferably 1.0 wt.-% to 4.0 wt.-%. In a preferred embodiment, 1-butene comonomer units are not present in the propylene ethylene elastomer (B).

[0104] Preferably, propylene, ethylene and optionally 1-butene are the only comonomers present in the propylene ethylene elastomer (B). Preferably, the propylene ethylene elastomer (B) is substantially free of units derived from other α-olefin monomers, i.e. C5 to C8 α-olefin monomers, e.g. it comprises less than 0.1 wt.-%, preferably less than 0.05 wt.-%, and more preferably less than 0.01 wt.-% of other α-olefin monomers, e.g. C5 to C8 α-olefin monomer units.

[0105] Preferably, the propylene ethylene elastomer (B) is obtainable or has been obtained by a polymerization process using a Ziegler-Natta catalyst. More preferably, the propylene ethylene elastomer (B) is produced using a Ziegler-Natta catalyst according to the preferred embodiments described herein for the preparation of the heterophasic polypropylene composition.

[0106] In a preferred embodiment all polymers of the heterophasic polypropylene composition are obtainable or have been obtained by a polymerisation process using Ziegler-Natta catalysts.

[0107] Preferably, the copolymer of ethylene (B) has a molecular weight distribution M w / M n (i.e. weight average molecular weight M w and number average molecular weight M n ) is in the range of 3.0 to 20.0, more preferably 4.0 to 15.0, and most preferably 5.5 to 9.0.

[0108] Ethylene homopolymer (C)

[0109] The polyolefin composition according to the present invention may comprise an ethylene homopolymer (C).

[0110] The ethylene homopolymer (C) preferably has a melt flow rate MFR2 (190°C), determined according to ISO 1133, in the range of 4 g / 10 min to 100 g / 10 min, preferably 7 g / 10 min to 80 g / 10 min, more preferably 10 g / 10 min to 50 g / 10 min, and most preferably 12 g / 10 min to 25 g / 10 min.

[0111] The ethylene homopolymer (C) preferably has a density between 910 kg / m 3 Up to 940kg / m 3 In the range of 910kg / m 3 Up to 930kg / m 3 , and more preferably 912 kg / m 3 Up to 925kg / m 3 .

[0112] Preferably, the ethylene homopolymer (C) has a melting temperature T m Within the range of 90°C to 125°C, 93°C to 120°C is more preferred, and 95°C to 110°C is still more preferred.

[0113] Preferably, the ethylene homopolymer (C) has a g' factor (80-100% cum) in the range of 0.10 to 0.90, more preferably 0.10 to 0.60 and even more preferably 0.10 to 0.45. The g' factor is the long chain branching (LCB) index, which is measured as described in the methods section herein.

[0114] Preferably, the ethylene homopolymer (C) is a low density polyethylene (LDPE).LDPE is well known in the art and is typically produced in a high pressure process carried out in a tubular reactor or an autoclave.

[0115] As ethylene homopolymer (C), polyethylene CA9150 produced by Borealis can be used.

[0116] Preparation of polyolefin compositions

[0117] The polyolefin composition according to the present invention may be prepared by any method known in the art. Preferably, the polyolefin composition is prepared by blending the heterophasic polypropylene composition with an ethylene homopolymer (C).

[0118] The present invention also relates to a process for preparing a polyolefin composition according to any of the above embodiments, wherein the process comprises preparing a heterophasic polypropylene composition by a multistage polymerization process and blending the heterophasic polypropylene composition with an ethylene homopolymer (C) to obtain the polyolefin composition.

[0119] Blending can be carried out by any method known in the art for polymer blending. Preferably, blending is carried out in the melt, more preferably by extrusion.

[0120] Preparation of heterophasic polypropylene compositions

[0121] The heterophasic polypropylene composition according to the polyolefin composition of the present invention can be prepared by any method known in the art.Ideally, the method employed can produce a homogeneous mixture of various components.Usually adopt the mode of blending (compounding).Blending generally relates to various components being mixed or / and blending under molten state, normally carries out by the mode of extruding.

[0122] Preferably, the heterophasic polypropylene composition is produced in a multistage process, wherein the propylene polymer is produced in a subsequent stage.

[0123] In a preferred embodiment, the heterophasic polypropylene composition is prepared by a multistage polymerization process. Preferably, the process comprises:

[0124] a) preparing a first propylene polymer component (A1) which is a propylene homopolymer or a propylene copolymer with 1-butene comonomer units and / or ethylene comonomer units in a first polymerization stage in a bulk phase reactor, preferably a loop reactor, in the presence of a Ziegler-Natta catalyst;

[0125] b) transferring the first propylene polymer component (A1) to a second polymerization stage and producing a second propylene polymer component (A2) which is a propylene copolymer with 1-butene comonomer units and optionally ethylene comonomer units in a first gas phase reactor (GPR1) in the presence of a Ziegler-Natta catalyst; and

[0126] wherein the first propylene polymer fraction (A1) and the second propylene polymer fraction (A2) together form a propylene copolymer (A) of propylene with 1-butene comonomer units in an amount in the range of 1.0 to 10.0 wt.-% and optionally ethylene comonomer units in an amount in the range of 0 to 6.0 wt.-%, said propylene copolymer (A) preferably having a melt flow rate MFR2 (230°C) determined according to ISO 1133 in the range of 30 to 400 g / 10 min;

[0127] c) transferring the propylene copolymer (A) to a third polymerization stage and preparing in a second gas phase reactor (GPR2) a propylene ethylene elastomer (B) having an ethylene content in the range of 20 to 60 wt.-% and optionally comprising 1-butene comonomer units, preferably in the presence of a Ziegler-Natta catalyst; to obtain a heterophasic polypropylene composition.

[0128] The heterophasic polypropylene composition preferably has a melt flow rate MFR2 (230°C) determined according to ISO 1133 in the range of 10 g / 10 min to 100 g / 10 min and a melting temperature T2 (230°C) determined according to ISO 11357-3 in the range of 150°C to 167°C. m .

[0129] The method can obtain a heterophasic polypropylene composition in any of the above embodiments.

[0130] Therefore, in the step a) of the method, propylene and optional 1-butene and / or ethene are fed into the bulk phase reactor. In the step b) of the method, propylene, 1-butene and optional ethene are fed into the first gas phase reactor, wherein the first gas phase reactor has been filled with the first propylene polymer component (A1). In the second gas phase reactor, propylene, ethene and optional 1-butene are added into the propylene copolymer (A) thus prepared, to obtain final propylene polymer in the step c) of the method.

[0131] Thus, preferably the propylene copolymer (A) is produced in a multistage process wherein the propylene polymer components (A1 ) and (A2) are produced in subsequent stages.

[0132] The properties of the second propylene polymer fraction (A2) produced in the higher stages of a multi-stage process can be calculated as follows.

[0133] The MFR2 of the second propylene polymer fraction (A2) produced in the second reactor is determined according to formula (1):

[0134]

[0135] in

[0136] MFR(A) is the MFR2 of the propylene copolymer (A)

[0137] w(A1) and w(A2) are the weight fractions of the propylene polymer component (A1) and the propylene polymer component (A2) in the propylene copolymer (A).

[0138] MFR(A1) is the MFR2 of the propylene polymer component (A1) produced in the first reactor.

[0139] The xylene soluble content of the second propylene polymer fraction (A2) produced in the second reactor is determined according to formula (2):

[0140]

[0141] in

[0142] XS(A) is the xylene soluble content of the propylene copolymer (A)

[0143] w(A1) and w(A2) are the weight fractions of the propylene polymer component (A1) and the propylene polymer component (A2) in the propylene copolymer (A).

[0144] XS(A1) is the xylene soluble content of the propylene polymer fraction (A1) produced in the first reactor.

[0145] The respectively adapted formulae can be used to determine the parameters of the second propylene polymer fraction (A2) or of polymers produced in subsequent stages of the process.

[0146] Thus, although the products of a multi-stage process cannot be measured directly, the properties of the polymers produced in the higher stages of such a multi-stage process can be determined by applying the above methods.

[0147] Polymers produced in a multistage process are often referred to as "in situ" blends. The final product consists of an intimate mixture of polymers from two or more reactors. The two polymers may have different molecular weight distributions and / or differ in comonomer content or type. Thus, the final product contains a mixture, or two or more polymers with different properties; that is, it is a multimodal polymer mixture.

[0148] The first polymerization stage for producing the first propylene polymer component (A1) is preferably a slurry polymerization step. Slurry polymerization is usually carried out in an inert diluent, and the inert diluent is usually a hydrocarbon diluent, such as methane, ethane, propane, n-butane, isobutane, pentane, hexane, heptane, octane, etc., or a mixture thereof. Preferably, the diluent is a low-boiling hydrocarbon with 1 to 4 carbon atoms or a mixture of such hydrocarbons. Particularly preferred diluent is propane, which may contain a small amount of methane, ethane and / or butane.

[0149] The temperature in the first polymerization stage is generally 60° C. to 100° C., preferably 70° C. to 90° C. Excessively high temperatures should be avoided to prevent partial dissolution of the polymer into the diluent and reactor fouling. The pressure is generally 1 bar to 150 bar, preferably 40 bar to 80 bar.

[0150] Slurry polymerization can be carried out in any known reactor for slurry polymerization, for example any bulk phase reactor. Such reactors include continuous stirred tank reactors and loop reactors. It is particularly preferred to carry out polymerization in a loop reactor. In such a reactor, the slurry is circulated at high speed along a closed pipeline using a circulation pump. Loop reactors are well known in the art, and examples are given, for example, in US-A-4582816, US-A-3405109, US-A-3324093, EP-A-479186 and US-A-5391654. Therefore, it is preferred to carry out the first polymerization stage with slurry polymerization in a loop reactor.

[0151] The slurry can be removed from the reactor continuously or intermittently. A preferred mode of intermittent extraction is to use settling legs, wherein the slurry is allowed to concentrate in the settling legs before removing a batch of concentrated slurry from the reactor. The use of settling legs is disclosed, for example, in US-A-3374211, US-A-3242150 and EP-A-1310295. For example, continuous extraction is disclosed in EP-A-891990, EP-A-1415999, EP-A-1591460 and WO-A-2007 / 025640. As disclosed in EP-A-1310295 and EP-A-1591460, continuous extraction is advantageously combined with a suitable concentration method. It is preferred to continuously remove the slurry from the first polymerization stage.

[0152] Hydrogen is typically introduced into the first polymerization stage for controlling the MFR2 of the propylene copolymer (A). As will be appreciated by a person skilled in the art, the amount of hydrogen required to reach the desired MFR2 depends on the used catalyst and polymerization conditions.

[0153] The average residence time in the first polymerization stage is generally 20 to 120 minutes, preferably 30 to 80 minutes. As is well known in the art, the average residence time τ can be calculated by the following formula (3):

[0154]

[0155] in

[0156] V R is the volume of the reaction space (in the case of a loop reactor, it is the volume of the reactor; in the case of a fluidized bed reactor, it is the volume of the fluidized bed)

[0157] Q o is the volume flow rate of the product stream (including polymer product and fluid reaction mixture)

[0158] The production rate is appropriately controlled by the catalyst feed rate. It is also possible to influence the production rate by appropriately selecting the monomer concentration. The desired monomer concentration can then be achieved by appropriately adjusting the propylene feed rate.

[0159] The first propylene polymer component (A1) is transferred to a second polymerization stage to produce a second propylene polymer component (A2), which second polymerization stage is preferably a gas phase polymerization step, i.e. carried out in a first gas phase reactor (GPR1). Any suitable gas phase reactor known in the art can be used, such as a fluidized bed gas phase reactor.

[0160] For gas phase reactors, the reaction temperature used will typically be in the range of 60°C to 115°C (e.g., 70°C to 110°C), the reactor pressure will typically be in the range of 10 bar to 25 bar, and the residence time will typically be 1 hour to 8 hours. The gas used will typically be a non-reactive gas, such as nitrogen or low boiling hydrocarbons, such as propane and monomers.

[0161] A chain transfer agent (such as hydrogen) is typically added to the second polymerization stage.

[0162] The ratio between the first polymeric component and the second polymeric component may be in the range of 25:75 to 75:25, more preferably 30:70 to 70:30, most preferably 35:65 to 65:35.

[0163] In the first gas phase reactor (GPR1 ) a mixture of the first propylene polymer fraction (A1 ) and the second propylene polymer fraction (A2) is formed, ie the propylene copolymer (A).

[0164] The propylene copolymer (A) is transferred to a third polymerization stage to produce the propylene ethylene elastomer (B), which is preferably a gas phase polymerization step, i.e. carried out in a second gas phase reactor (GPR2). Any suitable gas phase reactor known in the art can be used, for example a fluidized bed gas phase reactor. The above-mentioned range of conditions for the first gas phase reactor is equally applicable to the second gas phase reactor.

[0165] The ratio between the propylene copolymer (A) component and the propylene ethylene elastomer (B) component may be in the range of 90: 10 to 55: 45. The resulting polymer is a heterophasic polypropylene composition.

[0166] A preferred multi-stage process is the above-mentioned slurry-gas phase process, such as that developed by Borealis and known In this respect, reference is made to European patent applications EP-A-0887379 and EP-A-0517868.

[0167] The polymerization step may be preceded by a prepolymerization step. The purpose of prepolymerization is to polymerize a small amount of polymer over a catalyst at low temperature and / or low monomer concentration. Prepolymerization can improve the performance of the catalyst in the slurry and / or alter the properties of the final polymer. The prepolymerization step is typically carried out in a slurry.

[0168] Thus, the prepolymerization step can be carried out in a loop reactor. The prepolymerization is then preferably carried out in an inert diluent, typically a hydrocarbon diluent such as methane, ethane, propane, n-butane, isobutane, pentane, hexane, heptane, octane, etc., or a mixture thereof. Preferably, the diluent is a low-boiling hydrocarbon having 1 to 4 carbon atoms or a mixture of such hydrocarbons.

[0169] The temperature in the prepolymerization step is usually 0°C to 60°C, preferably 10°C to 50°C, more preferably 15°C to 40°C.

[0170] The pressure is not critical and is generally from 1 bar to 150 bar, preferably from 40 bar to 80 bar.

[0171] The amount of monomer is usually such that: every gram of solid catalyst component of polymerization in the prepolymerization step is 0.1 gram to 1000 gram of monomer. As known to those skilled in the art, the catalyst particles recovered from the continuous prepolymerization reactor do not all contain the same amount of prepolymer. On the contrary, each particle has its own characteristic amount, which depends on the residence time of the particle in the prepolymerization reactor. Since the residence time of some particles in the reactor is relatively long, while that of other particles is relatively short, the amount of prepolymer on different particles is also different, and some individual particles may contain an amount of prepolymer that exceeds the above-mentioned limit. However, the average amount of prepolymer on the catalyst is usually within the scope of the above-mentioned regulations.

[0172] As known in the art, the molecular weight of the prepolymer can be controlled by hydrogen.In addition, antistatic additives can be used to prevent the particles from adhering to each other or to the reactor walls, as disclosed in WO-A-96 / 19503 and WO-A-96 / 32420.

[0173] When a prepolymerization step is present, the catalyst components are preferably all introduced into the prepolymerization step. However, in the case where the solid catalyst component and the cocatalyst can be fed separately, it is possible that only a portion of the cocatalyst is introduced into the prepolymerization stage, and the remainder is introduced into the subsequent polymerization stage. In this case, it is necessary to introduce as much cocatalyst as possible into the prepolymerization stage in order to obtain sufficient polymerization reaction therein.

[0174] It is within the understanding of the present invention that the amount of polymer produced in the prepolymerization is typically in the range of 1.0 wt.-% to 5.0 wt.-%, based on the total weight of the heterophasic propylene composition.

[0175] The propylene copolymer (A) is preferably obtained by a polymerization process using a Ziegler-Natta catalyst. Preferably, both the first propylene polymer component (A1) and the second propylene polymer component (A2) are obtained by a polymerization process using a Ziegler-Natta catalyst. Also preferably, the propylene ethylene elastomer (B) is obtained by a polymerization process using a Ziegler-Natta catalyst. In a preferred embodiment, the Ziegler-Natta catalyst is used in all stages of the polymerization process.

[0176] Preferably, the Ziegler-Natta catalyst comprises:

[0177] a) one or more compounds of IUPAC Group 4 to Group 6 transition metals;

[0178] b) Group 2 metal compounds;

[0179] c) an internal donor, wherein the internal donor is a non-phthalate compound, preferably a non-phthalate ester;

[0180] d) a co-catalyst; and

[0181] e) Optional external donor.

[0182] The internal donor is preferably selected from (di)esters of non-phthalic carboxylic (di)acids, 1,3-diethers, derivatives thereof and mixtures thereof. The most preferred internal donor is a (di)ester of citraconic acid.

[0183] Preferably, the Ziegler-Natta catalyst does not contain phthalates and the heterophasic polypropylene composition does not contain phthalates and their respective decomposition products. Also preferably, the polyolefin composition does not contain phthalates and their respective decomposition products.

[0184] Suitable Ziegler-Natta catalysts for the above-mentioned polymerization reactions and their preparation are described in EP-A-3562850.

[0185] It will be understood that the propylene polymer may contain standard polymer additives as described above.

[0186] After preparation, the obtained polymer is usually extruded and pelletized. Extrusion can be carried out in a manner well known in the art, preferably in a twin-screw extruder. An example of a suitable twin-screw extruder is a co-rotating twin-screw extruder. For example, those are manufactured by Coperion or Japan Steel Works. Another example is a counter-rotating twin-screw extruder. Such extruders are manufactured by Kobe Steel and Japan SteelWorks, for example. Before extrusion, at least some of the desired additives mentioned above are preferably mixed with the polymer. The extruder generally includes a melting section for melting the polymer and a mixing section for homogenizing the polymer melt. Melting and homogenization are achieved by introducing energy into the polymer. Suitable levels of specific energy input (SEI) are from about 150 kWh / ton to about 450 kWh / ton, preferably from 175 kWh / ton to 350 kWh / ton of polymer.

[0187] Preparation of ethylene homopolymer (C)

[0188] The ethylene homopolymer (C) may be produced by any process known in the art for the production of ethylene homopolymers. Preferably, the ethylene homopolymer (C) is produced in a high pressure process, typically carried out in a tubular reactor or an autoclave.

[0189] As ethylene homopolymer (C) there may be used commercially available ethylene homopolymers having the required properties, for example polyethylene CA9150 produced by Borealis.

[0190] Products and uses

[0191] The present invention also relates to an article comprising the polyolefin composition according to any of the above embodiments of the present invention, and to the use of the polyolefin composition in the manufacture of an article. Preferred articles include films and molded articles.

[0192] The film can be prepared by any method known in the art, such as casting or extrusion. The film can be a multilayer film or a monolayer film, but is preferably a monolayer film. In one embodiment, the film is composed of a polyolefin composition as the sole polymer component.

[0193] As used herein, the term "molded article" refers to an article produced by any conventional molding technique, such as injection molding, stretch molding, compression molding, rotational molding or injection stretch blow molding. Articles produced by injection molding, stretch molding or injection stretch blow molding are preferred. Articles produced by injection molding are particularly preferred. The molded article is preferably a thin-walled article with a wall thickness of 300 μm to 2 mm. More preferably, the thin-walled article has a wall thickness of 300 μm to 1400 μm, and even more preferably the thin-walled article has a wall thickness of 500 μm to 900 μm. The molded article of the present invention can be a container, such as a cup, bucket, beaker, tray or a component of such an article, such as a transparent viewing window, lid or similar component.

[0194] The articles according to the invention can be used in a variety of end uses, in particular thin-wall packaging applications and food packaging applications. The articles according to the invention are particularly suitable for containing food, in particular frozen food, such as ice cream, frozen liquids, sauces, prepared convenience products and the like. DETAILED DESCRIPTION

[0195] Test Method

[0196] All parameters mentioned in the description of the present invention or examples were measured according to the following methods.

[0197] Melt flow rate

[0198] Melt flow rate (MFR) is measured according to ISO 1133 and expressed in g / 10 min. MFR is an indicator of the viscosity of a polymer melt. The MFR of PE is measured at 190°C, and the MFR of PP is measured at 230°C. The load under which the melt flow rate was measured is typically expressed as a subscript; for example, MFR2 is measured under a load of 2.16 kg (Condition D).

[0199] density

[0200] The density of the polymer is determined according to ISO 1183.

[0201] Quantitative description of microstructure by NMR spectroscopy

[0202] The comonomer content of the polymers was quantified using quantitative nuclear magnetic resonance (NMR) spectroscopy.

[0203] A Bruker Avance III 500 NMR spectrometer was used operating at 500.13 MHz and 125.76 MHz, respectively. 1 H and 13 C, record the quantity in the molten state 13 C{ 1 H} NMR spectra. All spectra were obtained using 13 Recordings were made at 180°C using a C-optimized 7 mm magic angle spinning (MAS) probehead, with nitrogen used for all pneumatics. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconium oxide MAS rotor and spun at 4 kHz. This setup was chosen primarily for the high sensitivity required for rapid identification and accurate quantification {klimke06, parkinson07, castignolles09}. Standard single-pulse excitation was employed, with a short NOE recycle delay of 3 s {pollard04, klimke06} and an RS-HEPT decoupling scheme {fillip05, griffin07}. A total of 1024 (1k) transients were acquired for each spectrum.

[0204] Quantitative 13 C{ 1 H} NMR spectra were processed, integrated, and the relevant quantitative properties were determined from the integration. All chemical shifts were internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm and assigned according to {brandolini01, randall89, resconi00}.

[0205] Characteristic signals corresponding to 1-butene incorporation were observed, and the comonomer content was quantified as follows. The amount of isolated 1-butene incorporated into the PBP sequence was quantified using the integration of the αB2 site at 43.6 ppm, which takes into account the number of reported sites for each comonomer:

[0206] B=I αB2 / 2

[0207] If continuous incorporation of 1-butene into the PBBP sequence is observed, the amount of continuously incorporated 1-butene in the PBBP sequence is quantified using the integral of the ααB2 site at 40.6 ppm, which takes into account the number of reported sites for each comonomer:

[0208] BB=2*I ααB2

[0209] In the presence of continuously incorporated 1-butene (BB), the isolated incorporated butene (B) needs to be corrected by subtracting BB / 2 due to signal contribution.

[0210] Characteristic signals corresponding to different levels of ethylene incorporation were observed, and the comonomer content was quantified for each sequence using the following distribution and formula:

[0211]

[0212] The amount of P is quantified based on the Sαα methylene sites, which include the additional propylene units not covered by Sαα:

[0213] P=I Sαα +B+(0.5*BB)+E+(0.5*EE)

[0214] The total amount of comonomer is then calculated as follows:

[0215] B 总 =B+BB E 总 =E+EE+EEE P 总 =P

[0216] B [mol%] = 100 * B 总 / (B 总 +E 总 +P 总 )

[0217] E[mol%]=100*E 总 / (B 总 +E 总 +P 总 )

[0218] P[mol%]=100*P 总 / (B 总 +E 总 +P 总 )

[0219] The weight percent comonomer incorporation was calculated from mol %:

[0220] B[wt%]=100*(B[mol%]*56.11) / ((E[mol%]*28.05)+(B[mol%]*56.11)+(P[mol%]*42.08))

[0221] E[wt%]=100*(E[mol%]*28.05) / ((E[mol%]*28.05)+(B[mol%]*56.11)+(P[mol%]*42.08))

[0222] For example, no xylene-soluble component of butene is observed, and the relevant equation simplifies to the following:

[0223] P=I Sαα +E+(0.5*EE)

[0224] The total amount of comonomer is then calculated as follows:

[0225] E 总 =E+EE+EEE P 总 =P

[0226] E[mol%]=100*E 总 / (E 总 +P 总 )

[0227] P[mol%]=100*P 总 / (E 总 +P 总 )

[0228] The weight percent comonomer incorporation was calculated from mol %:

[0229] E[wt%]=100*(E[mol%]*28.05) / ((E[mol%]*28.05)+(P[mol%]*42.08))

[0230] References:

[0231] klimke06: Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, HW, Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382.

[0232] parkinson07: Parkinson, M., Klimke, K., Spiess, HW, Wilhelm, M., Macromol. Chem. Phys. 2007; 208:2128.

[0233] pollard04: Pollard, M., Klimke, K., Graf, R., Spiess, HW, Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004;37:813.

[0234] filip05:Filip,X.,Tripon,C.,Filip,C.,J.Mag.Resn.2005,176,239

[0235] griffin07:Griffin,JM,Tripon,C.,Samoson,A.,Filip,C.,and Brown,SP,Mag.Res.in Chem.2007 45,S1,S198

[0236] castignolles09:Castignolles,P.,Graf,R.,Parkinson,M.,Wilhelm,M.,Gaborieau,M.,Polymer 50(2009)2373

[0237] resconi00:Resconi,L.,Cavallo,L.,Fait,A.,Pimontesi,F.,Chem.Rev.2000,100,1253

[0238] randall89: J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.

[0239] brandolini01: AJ Brandolini, DDHills, "NMR spectra of polymers and polymer additives", Marcel Deker Inc., 2000

[0240] abis86:L.Abis,Mackromol.Chem.187,1877-1886(1986)

[0241] Molecular weight and molecular weight distribution

[0242] The molecular weight average (M) was determined by gel permeation chromatography (GPC) according to ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D 6474-12 using the following formula: z , M w and M n ), molecular weight distribution (MWD) and its width, described by polydispersity index, PDI = M w / M n (where M n is the number average molecular weight, M w is the weight average molecular weight):

[0243]

[0244] For a constant elution volume interval ΔV i , where A i and M i is the chromatographic peak slice area and the molecular weight of polyolefin (M W ), respectively with the elution volume V i where N is equal to the number of data points obtained from the chromatogram between the integration limits.

[0245] A high-temperature GPC instrument equipped with an infrared (IR) detector (IR4 or IR5 from PolymerChar, Valencia, Spain) or a differential refractometer (RI) from Agilent Technologies, equipped with 3×Agilent-PLgel Ole×is and 1×Agilent-PLgel Ole×is Guard columns, was used. 1,2,4-Trichlorobenzene (TCB) stabilized with 250 mg / L of 2,6-di-tert-butyl-4-methyl-phenol was used as the solvent and mobile phase. The chromatography system was operated at 160°C and a constant flow rate of 1 mL / min. 200 μL of sample solution was injected for each analysis. Data were collected using Agilent Cirrus version 3.3 software or PolymerChar GPC-IR control software.

[0246] The column set was calibrated using a universal calibration method (according to ISO 16014-2:2003) using 19 narrow MWD polystyrene (PS) standards ranging from 0.5 kg / mol to 11,500 kg / mol. The PS standards were dissolved at room temperature for several hours. Conversion of polystyrene peak molecular weights to polyolefin molecular weights was accomplished using the Mark Houwink equation and the following Mark Houwink constants:

[0247] K PS =19×10 -3 mL / g,α PS =0.655

[0248] K PE =39×10 -3 mL / g,α PE =0.725

[0249] K PP =19×10 -3 mL / g,α PP =0.725

[0250] A third order polynomial fit was used to fit the calibration data.

[0251] All samples were prepared in the concentration range of 0.5 mg / mL to 1.0 mg / mL and dissolved at 160°C with continuous gentle shaking for 2.5 hours (PP) or 3 hours (PE). This method is particularly suitable for propylene polymers and polymer blends.

[0252] Average molecular weight, molecular weight distribution, long chain branching index (M by SEC / VISC-LS) n 、M w 、MWD、g'(80-100))

[0253] A PL 220 GPC (Agilent) equipped with an infrared detector (IR4 (PolymerChar, Spain), an online four-capillary bridge viscometer (PL-BV400-HT), and a dual light scattering detector with 15° and 90° angles (PL-LS15 / 90 light scattering detector) was used. Agilent 3×Olexis and 1×Olexis-Guard columns were used as stationary phases, and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) was used as the mobile phase at a constant flow rate of 1 mL / min at 160°C. 200 μL of sample solution was injected for each analysis. All samples were prepared as follows: 8.0 mg to 10.0 mg of polymer were dissolved in 10 mL (at 160°C) of stabilized TCB (same as the mobile phase) and incubated at 160°C with continuous gentle shaking for 2.5 hours. The column was heated at 160°C (c 160℃ ) The injection concentration of the polymer solution is determined as follows.

[0254]

[0255] Where: w 25 (polymer weight) and V 25 (Volume of TCB at 25°C).

[0256] GPC-VISC-LS Processing

[0257] For GPC light scattering method (GPC LS ), the inter-detector delay volume was determined using a narrow PS standard (MWD = 1.01) with a molar mass of 130,000 g / mol. The corresponding detector constants for the light scattering detector and the online viscometer were determined using the broad standard NIST 1475A (M w =52000 g / mol, IV=1.01 dl / g). The corresponding dn / dc used for the PE standard used in TCB is 0.094 cm 3Calculations were performed using Cirrus Multi-Offline SEC software version 3.2 (Agilent).

[0258] The molar mass of each elution slice was calculated using a 15° light scattering angle. Data collection, processing, and calculations were performed using Cirrus Multi-SEC software version 3.2. Molecular weights were calculated using the "use LS15angle" option in the "sample calculation options subfield slice MW data from" field in the Cirrus software. A value of 0.094 was used as the dn / dc ratio for molecular weight determination.

[0259] The molecular weight of each slice was calculated using the method described by C. Jackson and H.G. Barth at low angles. A linear fit was used to correlate the elution volume with the corresponding molecular weight for the low-molecular-weight region and high-molecular-weight region, where the LS or RI detectors provide less signal, respectively. The linear fit region was adjusted based on the sample.

[0260] The molecular weight average (M) was calculated by gel permeation chromatography (GPC) using the following formula: z (LS), M w (LS) and M n (LS)), molecular weight distribution (MWD) and its breadth (breadth described by the polydispersity index, PD(LS) = M w (LS) / M n (LS), where M n (LS) is the number average molecular weight, M w (LS) is the weight average molecular weight obtained from GPC-LS):

[0261]

[0262] For a constant elution volume interval ΔV i , where A i and M i(LS) is the chromatographic peak slice area and the molecular weight of polyolefin determined by GPC-LS (M W ).

[0263] Branching calculation g'(90-100% cum) or g'(85-100% cum)

[0264] The relative amount of branching is determined using the g'-index of a branched polymer sample. The long chain branching (LCB) index is defined as g' = [η] br / [η] linIt is well known that if the g' value increases, the branching content decreases. [η] is the intrinsic viscosity of a polymer sample at a specific molecular weight at 160°C in TCB and is measured by an online viscosity and concentration detector, where [η] lin is the intrinsic viscosity of a linear polymer with the same chemical composition. As described in the manual for Cirrus Multi-Offline SEC software version 3.2, the intrinsic viscosity is measured using the Solomon-Gatesman equation. [η] for a given molecular weight lin Using MarkHouwink's constant we get:

[0265] IV=K LLDPE *M α (Formula 1)

[0266] The constants K and α are specific to the polymer-solvent system and M is the molecular weight obtained from LS analysis.

[0267] In order to take into account the comonomer content in polyethylene co-α-olefin, [K] LLDPE Need to be corrected as follows:

[0268] K LLDPE =(1-(1-2 / x*wt.-%*(α-olefin)) 1+α *K PE (Formula 2)

[0269] where x is the number of C atoms in the α-olefin, and K PE The α-olefin content was determined by analyzing linear homopolymer PE (NIST 1475a) (using α = 0,725) and the α-olefin content was determined by 13 C-NMR determination. Usually K PE Between 0.00039 and 0.00042.

[0270] For linear low-density polyethylene (LDPE), an x ​​value of 8 is used to calculate K LLDPE value.

[0271] The IR detector determines the necessary concentration of each eluted slice.

[0272] [η] lin is the intrinsic viscosity of the linear sample, and [η] br is the viscosity of the branched sample with the same molecular weight and chemical composition. b ] divided by the intrinsic viscosity of the linear polymer at the same molecular weight [IV I ], the viscosity branching factor can be calculated.

[0273] In this case, g' (90-100)and g' (85-100) The calculation is done as follows: g' is calculated in the range of 80% to 100% of the cumulative score. M *a M Add the product of the concentration signal and divide it by the corresponding signal area a i .

[0274]

[0275] This method is particularly suitable for ethylene polymers.

[0276] References:

[0277] C.Jackson and HGBarth,"Molecular Weight Sensitive Detectors" in:Handbook of Size Exclusion Chromatography and related techniques,C.-S.Wu,2 nd ed., Marcel Dekker, New York, 2004, p.103.

[0278] Flexural modulus (FM)

[0279] Flexural modulus in 80×10×4 mm injection molded according to ISO 1873-2 3 The determination was carried out on test bars in a three-point bending test at 23°C according to ISO 178.

[0280] Differential Scanning Calorimetry (DSC)

[0281] Differential scanning calorimetry (DSC) analysis, melting temperature (T m ) and melt enthalpy (H m ), crystallization temperature (T c ) and heat of crystallization (H c , H CR ) was measured on 5 mg to 7 mg samples using a TA Instrument Q200 differential scanning calorimeter (DSC). The DSC was run according to ISO 11357 / Part 3 / Method C2 in a heating / cooling / heating cycle with a scan rate of 10°C / min over a temperature range of -30°C to +225°C. The crystallization temperature (T c ) and heat of crystallization (H c ) is determined from the cooling step, while the melting temperature (T m ) and melt enthalpy (H m ) is determined by the second heating step.

[0282] In the present specification, the term T m is understood to be the melting peak temperature determined by DSC at a heating rate of 10 K / min. In the present description, the term T c It is understood to be the crystallization peak temperature determined by DSC at a cooling rate of 10 K / min.

[0283] Notched Impact Strength (NIS)

[0284] Charpy notched impact strength (NIS) was measured according to ISO 179-1eA at +23°C or -20°C, using an 80×10×4 mm diameter test piece prepared according to ISO 1873-2. 3 Injection molded bar specimens.

[0285] Xylene soluble components

[0286] The xylene soluble fraction (XS) and the xylene insoluble fraction (XI) were determined at 25°C according to ISO 16152.

[0287] Intrinsic viscosity (IV)

[0288] IV of xylene solubles was measured according to ISO 1628-1 & 3 in decahydronaphthalene at 135°C.

[0289] Haze value

[0290] Haze values ​​are obtained on a 60×60×1 mm2 plastic injection molded according to EN ISO 1873-2. 3 The test was carried out on the plate according to ASTM 1003.

[0291] Opto-Mechanical Ability (OMA)

[0292] Opto-mechanical ability (OMA) is understood as the ratio of mechanical properties (especially impact and flexural properties) to optical properties (i.e. haze), where the goal is to have the highest possible mechanical properties and the lowest possible optical properties. Opto-mechanical ability is determined according to the following formula:

[0293]

[0294] The OMA calculated according to the NIS (-20°C) defined above is called OMA (-20°C).

[0295] Example

[0296] Preparation of heterophasic polypropylene compositions

[0297] Three heterophasic polypropylene compositions, namely the heterophasic polypropylenes hecoPP1, hecoPP2 and hecoPP3, were prepared in the form of particles in a multistage polymerization process as described above under the conditions listed in Table 1. The catalyst was a Ziegler-Natta catalyst prepared as described in EP-A-3562850. The solid catalyst component was used together with triethylaluminium (TEAL) as cocatalyst and dicyclopentyldimethoxysilane (D-donor) as external donor.

[0298] Table 1: Process conditions

[0299]

[0300]

[0301] The properties of the obtained heterophasic polypropylenes hecoP1, hecoP2 and hecoP3 and their respective xylene soluble fraction (XS) and xylene insoluble fraction (XI) are described in Table 2.

[0302] Table 2: Properties of heterophasic polypropylene.

[0303]

[0304]

[0305] nd = not determined

[0306] Preparation of polyolefin compositions

[0307] Heterophasic polypropylenes hecoPP1, hecoPP2 and hecoPP3 were prepared with polyethylene CA9150 (Borealis; MFR2 (190°C): 15 g / 10 min, density: 915 kg / m 3 , melting point (T m ), 104°C, and g' factor: 0.27) and the additives shown in Table 3 below were mixed and subsequently compounded in a twin-screw extruder ZSK 18 at a melt temperature of 200°C and a throughput of 7 kg / h. The polyolefin compositions thus obtained are respectively designated as Inventive Examples IE1, IE2, and IE3. A heterophasic polypropylene hecoPP1 containing no ethylene homopolymer (PE) was used as Comparative Example CE1.

[0308] Table 3: Contents of Examples

[0309] CE1 / hecoPP1 IE1 IE2 IE3 hPP1 wt.-% 99.4 82.4 0 0 hPP2 wt.-% 0 0 82.4 0 hPP3 wt.-% 0 0 0 82.4 B215 wt.-% 0.15 0.15 0.15 0.15 CaSt wt.-% 0.05 0.05 0.05 0.05 NX8000 wt.-% 0.4 0.4 0.4 0.4 PE wt.-% 0 17 17 17

[0310] B215(BAST)

[0311] CaSt = calcium stearate, CEASIT FI (Baerlocher),

[0312] NX TM 8000

[0313] The properties of the polyolefin compositions of Inventive Examples IE1, IE2 and IE3 and their respective xylene soluble fractions (XS) and xylene insoluble fractions (XI) are summarized in Table 4.

[0314] Table 4: Properties of polyolefin composition (I).

[0315]

[0316]

[0317] nd = not determined

[0318] Other properties of the polyolefin composition are described in Table 5. A random propylene copolymer produced in the presence of a Ziegler-Natta catalyst was used as comparative example CE2. The properties of this propylene copolymer are disclosed in WO 2015150467A1 (Example CE1). This polymer is typically used in packaging applications.

[0319] Table 5: Properties of polyolefin composition (II).

[0320] CE1 / hecoPP1 IE1 IE2 IE3 CE2 <![CDATA[MFR2]]> g / 10min 49.5 44 40 36 26 <![CDATA[T c ]]> ℃ 131 130 131 131 109 <![CDATA[T m1 ]]> ℃ 164 164 163 164 163 <![CDATA[T m2 ]]> ℃ nd 103 103 103 102 <![CDATA[H m1 ]]> J / g 98 77 70 71 70 <![CDATA[H m2 ]]> J / g nd 23 25 25 1.1 Haze ％ 99 47.8 59.7 52.3 55.6 NIS (23℃) <![CDATA[kJ / m 2 ]]> 3.9 5.9 8.1 6.8 7.9 NIS (-20℃) <![CDATA[kJ / m 2 ]]> 2.1 2.1 3.5 2.5 2.0 FM MPa 1517 1194 1052 1128 932 OMA(-20℃) <![CDATA[kJMPa / m 2 ]]> 31.6 52.5 61.3 53.3 33.5

[0321] nd = not determined

[0322] IE1 has lower haze when compared to CE1 (60×60×1mm 3 board), lower stiffness and similar temperature shock at -20°C. As shown in IE2, the temperature shock at -20°C is even improved when the xylene soluble fraction (XS) is increased.

[0323] All inventive examples have superior stiffness and temperature shock at -20° C. when compared to CE2. Optical properties are comparable or slightly improved.

[0324] Opto-mechanical properties (OMA, based on notched impact strength (NIS) at -20°C) values ​​show that all inventive examples have a better balance between stiffness, impact and optical properties than the comparative examples.

Claims

1. A polyolefin composition comprising: I) 55 to 95 wt.-% of a xylene insoluble fraction (XI), based on the total weight of the polyolefin composition and determined according to ISO 16152 at 25° C., said xylene insoluble fraction (XI) comprising comonomer units derived from propylene, comonomer units derived from ethylene in an amount in the range of 5.0 to 40.0 wt.-% and comonomer units derived from 1-butene in an amount in the range of 1.0 to 10.0 wt.-%, and II) 5 to 45 wt.-% of a xylene soluble fraction (XS), based on the total weight of the polyolefin composition and measured at 25° C. according to ISO 16152, said xylene soluble fraction (XS) comprising comonomer units derived from propylene, comonomer units derived from ethylene in an amount in the range of 20.0 to 60.0 wt.-% and optionally comonomer units derived from 1-butene, and said xylene soluble fraction (XS) having an intrinsic viscosity IV in the range of 1.2 to 3.0 dl / g, measured according to ISO 1628-1 & 3; and in, The polyolefin composition has at least two melting temperatures as measured by differential scanning calorimetry (DSC) as described in the specification, the first melting temperature T m1 In the range of 150°C to 167°C, and the second melting temperature T m2 In the range of 90°C to 125°C; and The melt flow rate MFR2 (230° C.), determined according to ISO 1133, is in the range of 20 to 80 g / 10 min.

2. The polyolefin composition according to claim 1, wherein I) The xylene-insoluble component (XI) comprises: a) a propylene copolymer (A) of propylene with 1-butene comonomer units in an amount in the range of 1.0 to 10.0 wt.-% and optionally ethylene comonomer units in an amount in the range of 0 to 6.0 wt.-%, preferably the propylene copolymer (A) has a melt flow rate MFR2 (230°C), determined according to ISO 1133, in the range of 30 to 400 g / 10 min; and b) an ethylene homopolymer (C), preferably an ethylene homopolymer (C) having a melt flow rate MFR2 (190° C.) in the range of 4 g / 10 min to 100 g / 10 min, measured according to ISO 1133, and in the range of 910 kg / m 3 Up to 940kg / m 3 Density within the range; and II) The xylene soluble fraction (XS) comprises: c) A propylene ethylene elastomer (B) having an ethylene content in the range of 20 to 60 wt.-%, and optionally comprising 1-butene comonomer units.

3. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition comprises a heterophasic polypropylene composition comprising a propylene copolymer of propylene and 1-butene comonomer units in an amount in the range of 1.0 to 10.0 wt.-% and optionally ethylene comonomer units in an amount in the range of 0 to 6.0 wt.-% (A), and a propylene ethylene elastomer (B) having an ethylene content in the range of 20 to 60 wt.-% and optionally comprising 1-butene comonomer units, preferably wherein, The propylene copolymer (A) is present in an amount of 55 to 90 wt.-% and the propylene ethylene elastomer (B) is present in an amount of 10 to 45 wt.-%, based on the total weight of the heterophasic polypropylene composition.

4. The polyolefin composition according to claim 3, wherein The polyolefin composition is a blend of the heterophasic polypropylene composition and the ethylene homopolymer (C), preferably wherein the heterophasic polypropylene composition is present in an amount of 75 to 95 wt.-% and the ethylene homopolymer (C) is present in an amount of 5 to 25 wt.-%, based on the total weight of the olefin composition.

5. The polyolefin composition according to any one of claims 2 to 4, wherein The propylene copolymer (A) and the propylene ethylene elastomer (B) are prepared in the presence of a Ziegler-Natta catalyst comprising: a) one or more compounds of IUPAC Group 4 to Group 6 transition metals; b) Group 2 metal compounds; c) an internal donor, wherein the internal donor is a non-phthalic acid compound, preferably a non-phthalate ester, and the internal donor is preferably selected from the group consisting of (di)esters, 1,3-diethers, derivatives thereof and mixtures thereof of non-phthalic (di)carboxylic acids; d) a co-catalyst; and e) Optional external donor.

6. The polyolefin composition according to any one of claims 2 to 5, wherein The propylene copolymer (A) is a multimodal propylene copolymer, preferably comprising the following two different propylene polymer fractions: a1) 25 to 75 wt.-%, based on the total weight of the propylene copolymer (A), of a first propylene polymer fraction (A1) which is a propylene homopolymer or a propylene copolymer of propylene with 1-butene comonomer units and / or ethylene comonomer units; and a2) 75 wt.-% to 25 wt.-% of a second propylene polymer component (A2), based on the total weight of the propylene copolymer (A), the second propylene polymer component (A2) being a propylene copolymer with 1-butene comonomer units and optionally ethylene comonomer units.

7. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition has a first melting temperature T m1 The first melting enthalpy H m1 In the range of 60 J / g to 95 J / g, and at the second melting temperature T m2 The second melting enthalpy H m2 In the range of 5 J / g to 50 J / g, wherein the melting temperature and the melting enthalpy are measured according to the differential scanning calorimetry (DSC) described in the specification.

8. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition has a flexural modulus greater than 950 MPa measured according to ISO 178 and / or an opto-mechanical ability (OMA (-20° C.)) greater than 35 kJ MPa / m² at -20° C., measured as described in the specification. 2 .

9. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition has a diameter of 60×60×1 mm according to ASTM 1003. 3 and / or a crystallization temperature T in the range of 105° C. to 140° C. as measured by differential scanning calorimetry (DSC) as described in the specification. c .

10. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition has a thermal conductivity of 4.0 kJ / m at +23° C., measured according to ISO 179 / 1eA. 2 Up to 15.0kJ / m 2 Impact strength within the range of 1.8 kJ / m² and / or 1.8 kJ / m² at -20°C according to ISO 179 / 1eA 2 Up to 10.0 kJ / m 2 Impact strength within the range.

11. The polyolefin composition according to any one of the preceding claims, wherein The polyolefin composition comprises a 1-butene content in the range of 0.5 wt.-% to 5.0 wt.-%, as determined by NMR spectroscopy.

12. A process for preparing a polyolefin composition according to any one of the preceding claims, wherein The method comprises preparing a heterophasic polypropylene composition by a multistage polymerization process, and blending the heterophasic polypropylene composition with an ethylene homopolymer (C) to obtain the polyolefin composition.

13. The method according to claim 12, wherein: The multi-stage polymerization process comprises: a) preparing a first propylene polymer component (A1) which is a propylene homopolymer or a propylene copolymer with 1-butene comonomer units and / or ethylene comonomer units in a first polymerization stage in a bulk phase reactor, preferably a loop reactor, in the presence of a Ziegler-Natta catalyst; b) transferring the first propylene polymer component (A1) to a second polymerization stage and producing in a first gas phase reactor (GPR1) a second propylene polymer component (A2) which is a propylene copolymer with 1-butene comonomer units and optionally ethylene comonomer units in the presence of a Ziegler-Natta catalyst; and wherein the first propylene polymer fraction (A1) and the second propylene polymer fraction (A2) together form a propylene copolymer (A) of propylene with 1-butene comonomer units in an amount in the range of 1.0 to 10.0 wt.-% and optionally ethylene comonomer units in an amount in the range of 0 to 6.0 wt.-%, said propylene copolymer (A) preferably having a melt flow rate MFR2 (230°C) determined according to ISO 1133 in the range of 30 to 400 g / 10 min; c) transferring the propylene copolymer (A) to a third polymerization stage and preparing in a second gas phase reactor (GPR2) a propylene ethylene elastomer (B) having an ethylene content in the range of 20 to 60 wt.-% and optionally comprising 1-butene comonomer units, preferably in the presence of a Ziegler-Natta catalyst; to obtain a heterophasic polypropylene composition preferably having a melt flow rate MFR2 (230°C), measured according to ISO 1133, in the range of 10 to 100 g / 10 min and a melting temperature T 200 to 150 to 167°C, measured according to ISO 11357-3. m .

14. An article comprising the polyolefin composition according to any one of claims 1 to 11, preferably a film or a molded article.

15. Use of the polyolefin composition according to any one of claims 1 to 11 for the manufacture of an article, preferably a film or a molded article.

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