High melting point heterophasic polypropylene composition

Abstract

The invention relates to a heterophasic polypropylene composition with high melting temperature, moderate softness and high impact strength. Specifically, the present invention relates to a heterophasic polypropylene composition comprising a propylene copolymer (A) matrix of propylene with ethylene and 1-butene comonomer units and a propylene ethylene elastomer (B) dispersed in the matrix. Furthermore, the present invention relates to a process for preparing said heterophasic polypropylene composition in the presence of a Ziegler-Natta catalyst, as well as to articles comprising said heterophasic polypropylene composition and to the use of said heterophasic polypropylene composition in articles.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heterophasic polypropylene composition having a high melting temperature, moderate softness and high impact strength. In particular, the present invention relates to a heterophasic polypropylene composition comprising a matrix of a propylene copolymer (A) of propylene with ethylene and 1-butene comonomer units and a propylene ethylene elastomer (B) dispersed in the matrix. Furthermore, the present invention relates to a process for the production of the heterophasic polypropylene composition in the presence of a Ziegler-Natta catalyst, to an article comprising the heterophasic polypropylene composition and to the use of the heterophasic polypropylene composition in an article. BACKGROUND

[0002] Plastic packaging is widely used in daily life due to its good cost / performance balance. In these applications, polyolefin polymers based on polypropylene and / or polyethylene are often used. In order to adjust the properties of these polymers, other higher alpha-olefin comonomers, such as 1-butene and 1-hexene, are often used. The use of such higher alpha-olefins allows great flexibility in improving the selection properties of the final polymer.

[0003] Due to the excellent property balance of heterophasic propylene copolymers, it is often used in the packaging field. For example, EP-A-3126411 describes a heterophasic propylene copolymer comprising a matrix of an alpha-olefin copolymer of propylene-C4 to C 12 alpha-olefin copolymer and a propylene-ethylene elastomer as a dispersed phase. The heterophasic propylene polymer is produced with a single-site solid particulate catalyst. The exemplary polymer is characterized by having good mechanical properties, such as moderate to higher flexibility, but its impact strength still has room for improvement. In addition, it is often desirable for the polymer to be applicable over a wide temperature range, so it is crucial to improve the temperature properties of the polymer. SUMMARY

[0004] OBJECTIVE Therefore, it is an object of the present invention to provide a new polypropylene composition suitable for a wide temperature range, wherein the polypropylene composition is able to provide high impact strength at moderate softness at the same time. In particular, a polypropylene composition suitable for use in the packaging field, such as molded articles or films, is needed.

[0005] In addition, it is desirable to provide a polypropylene composition with the above-mentioned properties with a smaller number of different components, because a relatively uncomplicated polymer composition is easier to recycle after use. SUMMARY Surprisingly, the above objective can be achieved by a multiphase polypropylene composition comprising a propylene copolymer (A) matrix of propylene, ethylene, and 1-butene comonomer units, and a propylene-ethylene elastomer (B) dispersed in the matrix. Based on the total weight of the multiphase polypropylene composition and determined according to ISO 16152 at 25°C, 25 to 50% by weight of xylene soluble (XS), said xylene soluble comprising propylene comonomer units and ethylene comonomer units in the range of 18.0 to 35.0% by weight based on the total weight of said xylene soluble (XS), and said xylene soluble (XS) having an intrinsic viscosity IV of 1.8 to 3.0 dl / g as determined according to ISO 1628-1&3; and Wherein based on the total weight of the multiphase polypropylene composition and by 13 C-NMR spectroscopy determined that the multiphase polypropylene composition comprises 1-butene comonomer units in the range of 3.0 to 10.0 wt% and ethylene comonomer units in the range of 5.0 to 15.0 wt%, and wherein the multiphase polypropylene has: i) Melt flow rate MFR2 (230°C) as determined according to ISO 1133, in the range of 0.1 to 20.0 g / 10 min; and ii) The melting temperature T, determined by differential scanning calorimetry (DSC) as described in the specification, within the range of 157 to 170°C. m .

[0007] By selecting specific comonomers and their content in the polymer, as well as the ethylene content in xylene-soluble (XS), polymers with the aforementioned good balance of properties can be obtained. These polymers are characterized by high melting temperatures, thus allowing for use over a wide temperature range. They exhibit moderate softness and high impact strength.

[0008] Furthermore, it has been found that the above-mentioned objective can be achieved by a method for preparing the multiphase polypropylene composition according to the present invention via a multi-stage polymerization method, the method comprising: I) In the presence of a Ziegler-Natta catalyst, during the first polymerization stage, in a bulk reactor, preferably a loop reactor, a first propylene polymer fraction (A1) is prepared, wherein the first propylene polymer fraction (A1) is a propylene homopolymer or a propylene copolymer of propylene and ethylene comonomer units. II) transferring the first propylene polymer fraction (Al) to a second polymerization stage and producing a second propylene polymer fraction (A2) which is a propylene copolymer of propylene with ethylene and 1-butene comonomer units in a first gas phase reactor (GPR1) in the presence of a Ziegler-Natta catalyst; and wherein the first propylene polymer fraction (Al) and the second propylene polymer fraction (A2) together form a propylene copolymer (A); and III) transferring the propylene copolymer (A) to a third polymerization stage and producing a propylene ethylene elastomer (B) as a third propylene polymer fraction in a second gas phase reactor (GPR2) in the presence of a Ziegler-Natta catalyst to obtain a heterophasic polypropylene composition.

[0009] The use of a Ziegler-Natta catalyst in the claimed process further allows to obtain the desired properties. By using a new generation of Ziegler-Natta catalysts, the use of phthalate compounds can be avoided and the risk of contamination of the final product with phthalates is minimized.

[0010] Articles, preferably films and molded articles, comprising the heterophasic polypropylene composition as well as the use of the heterophasic polypropylene composition in articles can impart good properties to the articles. These articles are characterized by having a high melting temperature, while at the same time, by having a high impact strength at moderate softness. DETAILED DESCRIPTION

[0011] Heterophasic polypropylene composition The present invention relates to a heterophasic polypropylene composition.

[0012] The heterophasic polypropylene composition according to the present invention comprises or consists of a propylene copolymer (A) matrix of propylene with ethylene and 1-butene comonomer units and a propylene ethylene elastomer (B) dispersed in the matrix. Thus, the heterophasic polypropylene composition is a terpolymer of propylene, ethylene and 1-butene.

[0013] The term "heterophasic" as used herein means that at least two different phases are present in the composition, i.e. the propylene copolymer (A) and the propylene ethylene elastomer (B). The propylene copolymer (A) forms a crystalline matrix of the heterophasic polypropylene composition, the propylene ethylene elastomer (B) is dispersed in the crystalline matrix. The presence of the different phases can be detected by DSC analysis: the crystalline matrix propylene copolymer (A) will show a higher melting point than the propylene ethylene elastomer (B). Heterophasic polypropylene composition The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a crystalline matrix of the heterophasic polypropylene composition. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene copolymer (A) is a propylene copolymer of propylene with ethylene and 1-butene comonomer units. The propylene cop

[0014] The term "propylene-based polymer" as used herein refers to a polymer comprising at least 50 wt.-% of propylene monomer units and further comonomer units different from propylene. Propylene copolymer The term "propylene-based polymer" as used herein refers to a polymer comprising at least 50 wt.-% of propylene monomer units and further comonomer units different from propylene.

[0015] The term "propylene-based polymer" as used herein refers to a polymer comprising at least 50 wt.-% of propylene monomer units and further comonomer units different from propylene. Alpha-olefins The term "propylene-based polymer" as used herein refers to a polymer comprising at least 50 wt.-% of propylene monomer units and further comonomer units different from propylene.

[0016] Unless stated otherwise, all percentages in the present disclosure are weight percentages (wt.-%) based on the total weight of the respective closed entity.

[0017] The heterophasic polypropylene composition comprises 25 to 50 wt.-%, preferably 28 to 45 wt.-%, more preferably 30 to 40 wt.-% of xylene solubles (XS) based on the total weight of the heterophasic polypropylene composition and determined at 25 °C according to ISO 16152.

[0018] The xylene solubles (XS) comprise propylene comonomer units and, based on the total weight of the xylene solubles (XS), ethylene comonomer units in an amount in the range of 18.0 to 35.0 wt.-%, preferably in the range of 19.0 to 34.0 wt.-%, more preferably in the range of 20.0 to 33.0 wt.-%.

[0019] The xylene solubles (XS) can further comprise 1-butene comonomer units. Preferably, the xylene solubles (XS) further comprise 1-butene comonomer units in an amount in the range of 0.0 to 8.0 wt.-%, preferably in the range of 3.0 to 7.5 wt.-%, more preferably in the range of 3.5 to 7.0 wt.-%, based on the total weight of the xylene solubles (XS).

[0020] Thus, the xylene solubles (XS) comprise or consist of propylene comonomer units, ethylene comonomer units and, optionally, 1-butene comonomer units.

[0021] Preferably, the total amount of ethylene and 1-butene comonomer units in the xylene solubles (XS) is in the range of 18.0 to 43.0 wt.-%, preferably in the range of 22.0 to 41.5 wt.-%, more preferably in the range of 23.5 to 40.0 wt.-%, based on the total weight of the xylene solubles (XS).

[0022] Typically, the xylene solubles (XS) comprise propylene ethylene elastomer (B). Preferably, the xylene solubles (XS) comprise a content of propylene ethylene elastomer (B) of at least 50 wt.%, more preferably of at least 60 wt.%, and up to 100 wt.%, based on the total weight of the xylene solubles (XS).

[0023] The xylene solubles (XS) have an intrinsic viscosity IV determined according to ISO 1628-1 & 3 in the range of 1.8 to 3.0 dl / g, preferably in the range of 1.9 to 2.8 dl / g, more preferably in the range of 2.0 to 2.6 dl / g.

[0024] Typically, the heterophasic polypropylene composition further comprises xylene insolubles (XI) in an amount of 50 to 75 wt.%, respectively, of the heterophasic polypropylene composition, based on the total weight of the heterophasic polypropylene composition and determined at 25°C according to ISO 16152. Preferably, the xylene insolubles (XI) comprise or consist of propylene comonomer units, ethylene comonomer units and 1-butene comonomer units.

[0025] Typically, the xylene insolubles (XI) comprise a higher content of propylene copolymer (A). Preferably, the xylene insolubles (XI) comprise a content of propylene copolymer (A) of at least 70 wt.%, more preferably of at least 80 wt.%, and up to 100 wt.%, based on the total weight of the xylene insolubles (XI).

[0026] Preferably, the total content of xylene insolubles (XI) and xylene solubles (XS) amounts to 100 wt.% of the propylene polymer content of the heterophasic polypropylene composition. More preferably, their total content amounts to 100 wt.% of the total polymer content of the heterophasic polypropylene composition. However, it is to be understood that additives can also be present in the heterophasic polypropylene composition as described below.

[0027] Therefore, preferably, the heterophasic polypropylene composition consists of xylene insolubles (XI) and xylene solubles (XS) and optionally additives.

[0028] The heterophasic polypropylene composition comprises a content of 1-butene comonomer units in the range of 3.0 to 10.0 wt.%, preferably in the range of 3.5 to 8.0 wt.%, more preferably in the range of 4.0 to 6.5 wt.%, and a content of ethylene comonomer units in the range of 5.0 to 15.0 wt.%, preferably in the range of 5.5 to 12.0 wt.%, more preferably in the range of 6.0 to 10.0 wt.%, based on the total weight of the heterophasic polypropylene composition and determined by 13 C-NMR spectroscopy.

[0029] Preferably, the total content of both comonomer units, i.e. 1 -butene comonomer units and ethylene comonomer units, is in the range of 8.0 to 25.0 wt.-%, more preferably in the range of 9.0 to 20.0 wt.-%, most preferably in the range of 10.0 to 16.5 wt.-%.

[0030] The heterophasic polypropylene composition has a melt flow rate MFR2 (230 °C) determined according to ISO 1133 in the range of 0.1 to 20.0 g / 10 min, more preferably in the range of 0.8 to 15.0 g / 10 min, more preferably in the range of 1.0 to 10.0 g / 10 min.

[0031] The heterophasic polypropylene composition is characterized by its melting temperature Tm m which is high.

[0032] Thus, the heterophasic polypropylene composition has a melting temperature Tm m determined according to the differential scanning calorimetry (DSC) as described herein in the range of 157 to 170 °C, preferably in the range of 158 to 167 °C, more preferably in the range of 159 to 165 °C.

[0033] The heterophasic polypropylene composition has a first glass transition temperature Tg g1 and a second glass transition temperature Tg g2 determined according to ISO 6721-7. The first glass transition temperature Tg g1 is the glass transition temperature of the propylene copolymer (A) matrix, while the second glass transition temperature Tg g2 is the glass transition temperature of the propylene ethylene elastomer (B). The first glass transition temperature Tg g1 is typically higher than the second glass transition temperature Tg g2 .

[0034] Preferably, the first glass transition temperature Tg g1 is in the range of -12 to +2 °C, more preferably in the range of -10 to 0 °C, more preferably in the range of -8 to -2 °C. Preferably, the second glass transition temperature Tg g2 is in the range of -55 to -35 °C, more preferably in the range of -52 to -37 °C, even more preferably in the range of -50 to -38 °C.

[0035] Preferably, the heterophasic polypropylene composition is free of acid esters of phthalic acid and their respective decomposition products.

[0036] The heterophasic polypropylene composition is characterized by a high melting temperature and a moderate softness.

[0037] Preferably, the heterophasic polypropylene composition has a flexural modulus determined according to ISO 178 in the range of 300 to 700 MPa, more preferably in the range of 350 to 600 MPa, most preferably in the range of 400 to 550 MPa.

[0038] The heterophasic polypropylene composition is further characterized by a high impact strength (determined as Charpy notched impact strength).

[0039] Preferably, the heterophasic polypropylene composition has an impact strength at +23°C determined according to ISO 179 / 1 eA in the range of 65.0 to 120.0 kJ / m 2 , more preferably in the range of 70.0 to 100.0 kJ / m 2 , most preferably in the range of 75.0 to 95.0 kJ / m 2 .

[0040] Preferably, the crystallization temperature Tc of the heterophasic polypropylene composition is 114°C or more, for example in the range of 115 to 125°C, more preferably in the range of 115 to 124°C, most preferably in the range of 116 to 123°C, determined according to the differential scanning calorimetry (DSC) as described herein for non-nucleated heterophasic polypropylene composition; and / or 120°C or more, for example in the range of 121 to 135°C, more preferably in the range of 122 to 130°C, most preferably in the range of 123 to 129°C, determined according to the differential scanning calorimetry (DSC) as described herein for nucleated heterophasic polypropylene composition. The term ‘ Nucleation ’ refers to alpha nucleation, which can be achieved by the presence of external nucleating agents, by Borealis Nucleation Technology (BNT) or by a combination of both.

[0041] Preferably, propylene, 1 -butene and ethylene are the only monomers in the heterophasic polypropylene composition. Preferably, the heterophasic polypropylene composition is essentially free of units derived from other alpha-olefin monomers (i.e. C5 to C8 alpha-olefin monomers), for example, it comprises less than 0.10 wt.-%, preferably less than 0.05 wt.-%, more preferably less than 0.01 wt.-% of other alpha-olefin monomers, for example C5 to C8 alpha-olefin monomer units.

[0042] The comonomer content in the heterophasic polypropylene composition, the xylene solubles (XS) and the propylene copolymer was determined using 13 C-NMR spectroscopy as described in the methods section.

[0043] The heterophasic polypropylene composition is preferably obtained by a polymerization process using a Ziegler-Natta catalyst. Preferably, the heterophasic polypropylene composition is manufactured using a Ziegler-Natta catalyst according to the preferred embodiments for the preparation of the heterophasic polypropylene composition as described herein.

[0044] Preferably, the propylene copolymer (A) and the propylene ethylene elastomer (B) are the only propylene polymer components in the heterophasic polypropylene composition.

[0045] Preferably, the weight ratio of the propylene ethylene elastomer (B) to the propylene copolymer (A) in the heterophasic polypropylene composition is in the range of 10:90 to 25:75, more preferably in the range of 12:88 to 22:78. In other words, preferably, the heterophasic polypropylene composition comprises 75 to 90 wt.-%, more preferably 78 to 88 wt.-%, of the propylene copolymer (A) and 12 to 22 wt.-% of the propylene ethylene elastomer (B), based on the total weight of the heterophasic polypropylene composition.

[0046] It is understood herein that the heterophasic polypropylene composition can comprise further components, such as additives, which can optionally be added in the form of a mixture with or without a carrier polymer (e.g. in the form of a masterbatch).

[0047] Suitable additives include fillers, lubricants, processing aids, antioxidants, ultraviolet light absorbers, light stabilizers, nucleating agents, blowing or foaming agents, clarifiers, and pigments.

[0048] The content of the additives ranges from 0.1 to 10.0 wt.-%, preferably from 0.1 to 5.0 wt.-%, more preferably from 0.1 to 3.0 wt.-%, based on the total weight of the heterophasic polypropylene composition.

[0049] In one particular embodiment, the nucleating agent is used in an amount of 0.05 to 0.2 wt.-%. One preferred nucleating agent is ADK STAB NA-71, commercially available from Adeka, France, which comprises more than 90 wt.-% of 2,2'-methylenebis-(2,6-di-tert-butylphenyl)phosphoric acid lithium salt (CAS No.: 85209-93-4).

[0050] Propylene copolymer (A) The propylene copolymer (A) forms the crystalline matrix of the heterophasic polypropylene composition. The propylene copolymer (A) is a copolymer of propylene with 1-butene comonomer units and ethylene comonomer units.

[0051] Preferably, the propylene copolymer (A) has a content of 1-butene comonomer units in the range of 2.0 to 6.0 wt.-%, more preferably in the range of 2.5 to 5.5 wt.-%, and a content of ethylene comonomer units in the range of 1.0 to 3.9 wt.-%, more preferably in the range of 1.5 to 3.5 wt.-%, based on the total weight of the propylene copolymer (A).

[0052] Preferably, propylene, 1 -butene and ethylene are the only monomers in the propylene copolymer (A). Preferably, the propylene copolymer (A) is essentially free of units derived from other alpha-olefin monomers, i.e. C5 to C8 alpha-olefin monomers, e.g. it comprises less than 0.10 wt.-%, preferably less than 0.05 wt.-%, more preferably less than 0.01 wt.-% of other alpha-olefin monomers, e.g. C5 to C8 alpha-olefin monomer units.

[0053] The propylene copolymer (A) is preferably a multimodal polymer. The term ‘multimodal’ as used herein denotes a polymer composition comprising at least two polymer fractions which are generated under different polymerization conditions, resulting in the fractions having different (weight average) molecular weights and / or molecular weight distributions and / or different comonomer contents. The prefix ‘multimodal’ denotes the number of different polymer fractions which make up the polymer. The term “multimodal” includes bimodal, trimodal, tetramodal and the like polymers. Multimodal polymer Multimodal polymer First propylene polymer fraction (A1)

[0054] More preferably, the propylene copolymer (A) is a bimodal polymer, i.e. it consists of or comprises two different polymer fractions, i.e. a first propylene polymer fraction (A1 ) and a second propylene polymer fraction (A2).

[0055] Preferably, the first propylene polymer fraction (A1 ) and the second propylene polymer fraction (A2) are produced in the order of the consecutive polymerization stages.

[0056] Preferably, the propylene copolymer (A) comprises or consists of 30 to 70 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 with ethylene comonomer units, preferably a propylene homopolymer; and 30 to 70 wt.-%, based on the total weight of the propylene copolymer (A), of a second propylene polymer fraction (A2) which is a propylene copolymer with ethylene comonomer units and 1 -butene comonomer units.

[0057] In other words, the weight ratio of the first propylene polymer fraction (A1 ) to the second propylene polymer fraction (A2) in the propylene copolymer (A) is preferably in the range of 30:70 to 70:30, more preferably in the range of 35:65 to 65:35, most preferably in the range of 40:60 to 60:40.

[0058] ​​​The second propylene polymer fraction (A2) is different from the first propylene polymer fraction (A1 ). Preferably, the second propylene polymer fraction (A2) has a higher total comonomer content than the first propylene polymer fraction (A1 ). More preferably, the second propylene polymer fraction (A2) has a higher content of ethylene and 1 -butene comonomer units than the first propylene polymer fraction (A1 ).

[0059] Preferably, the propylene copolymer (A) has a molecular weight distribution Mw / Mn in the range of 3.0 to 10.0, more preferably 4.0 to 8.0, most preferably 5.5 to 7.0. w / M n The weight average molecular weight Mw of the propylene copolymer (A) is preferably in the range of 100,000 to 1,000,000 g / mol, more preferably in the range of 150,000 to 800,000 g / mol, most preferably in the range of 200,000 to 600,000 g / mol. w The number average molecular weight Mn of the propylene copolymer (A) is preferably in the range of 50,000 to 500,000 g / mol, more preferably in the range of 70,000 to 400,000 g / mol, most preferably in the range of 80,000 to 300,000 g / mol. n The ratio of the weight average molecular weight Mw to the number average molecular weight Mn of the propylene copolymer (A) is preferably in the range of 2.0 to 10.0, more preferably in the range of 2.5 to 8.0, most preferably in the range of 3.0 to 6.0.

[0060] The propylene copolymer (A) preferably has a melt flow rate MFR2(230 °C) determined according to ISO 1133 in the range of 0.5 to 30.0 g / 10 min, more preferably in the range of 0.6 to 25.0 g / 10 min, most preferably in the range of 0.7 to 20.0 g / 10 min.

[0061] Second propylene polymer fraction (A2) The first propylene polymer fraction (A1 ) of the propylene copolymer (A) preferably consists of a single propylene polymer.

[0062] The propylene polymer of the first propylene polymer fraction (A1 ) is preferably a propylene homopolymer or a copolymer of propylene and ethylene comonomer units and optionally 1 -butene comonomer units.

[0063] More preferably, the first propylene polymer fraction (A1 ) has a content of ethylene comonomer units in the range of 0 to less than 2.0 wt.-%, more preferably in the range of 0 to less than 1.0 wt.-%, based on the total weight of the first propylene polymer fraction (A1 ), most preferably the first propylene polymer fraction (A1 ) is a propylene homopolymer.

[0064] The first propylene polymer fraction (A1 ) preferably has a melt flow rate MFR2(230 °C) determined according to ISO 1133 in the range of 0.2 to 10.0 g / 10 min, more preferably in the range of 0.5 to 8.0 g / 10 min, most preferably in the range of 0.8 to 6.0 g / 10 min.

[0065] MFR (A) The second propylene polymer fraction (A2) of the propylene copolymer (A) preferably consists of a single propylene polymer.

[0066] The propylene polymers of the second propylene polymer fraction (A2) are preferably propylene copolymers of propylene and 1 -butene comonomer units and ethylene comonomer units.

[0067] The second propylene polymer fraction (A2) preferably has a melt flow rate MFR2 (230 °C) determined according to ISO 1133 in the range of 0.1 to 20.0 g / 10 min, preferably in the range of 0.8 to 15.0 g / 10 min, more preferably in the range of 1.0 to 10.0 g / 10 min.

[0068] The MFR2 of the second propylene polymer fraction (A2) produced in the second polymerization stage is determined according to formula (1): Formula (1) wherein w (A1) MFR2 is the MFR2 of the propylene copolymer (A); w (A2) and MFR (A1) wA1 and wA2 are the weight fractions of the propylene polymer fractions (A1) and (A2), respectively, in the propylene copolymer (A); Propylene ethylene elastomer (B) MFR2 is the MFR2 of the propylene polymer fraction (A1) produced in the first polymerization stage.

[0069] The parameters of the second propylene polymer fraction (A2) or of the polymer produced in the further polymerization stage of the production process can be determined using the respective formula.

[0070] Preferably, the second propylene polymer fraction (A2) comprises 1 -butene comonomer units in an amount in the range of 6.0 to 18.0 wt.-%, more preferably in the range of 8.0 to 16.0 wt.-%, most preferably in the range of 10.0 to 15.0 wt.-%, and ethylene comonomer units in an amount in the range of 4.0 to 15.0 wt.-%, more preferably in the range of 5.0 to 13.0 wt.-%, most preferably in the range of 6.0 to 12.0 wt.-%, based on the total weight of the second propylene polymer fraction (A2).

[0071] Preparation of heterophasic polypropylene composition The heterophasic polypropylene composition further comprises a propylene ethylene elastomer (B). The propylene ethylene elastomer (B) forms a dispersed phase dispersed in a crystalline matrix.

[0072] The propylene ethylene elastomer (B) is a copolymer of propylene and ethylene. Preferably, the propylene ethylene elastomer (B) is a unimodal propylene copolymer.

[0073] Preferably, the content of ethylene in the propylene-ethylene elastomer (B) is in the range of 20 to 60 wt.-%, more preferably in the range of 22 to 50 wt.-%, most preferably in the range of 25 to 45 wt.-%, based on the total weight of the propylene-ethylene elastomer (B). The content of ethylene is determined by 13 C-NMR spectroscopy.

[0074] The propylene-ethylene elastomer (B) can comprise 1-butene comonomer units. The content of 1-butene comonomer units in the propylene-ethylene elastomer (B) is preferably in the range of 0 to 5.0 wt.-%.

[0075] Preferably, propylene and ethylene and optionally 1-butene are the only monomers in the propylene-ethylene elastomer (B). Preferably, the propylene-ethylene elastomer (B) is essentially free of units derived from other alpha-olefin monomers (i.e. C5 to C8 alpha-olefin monomers), e.g. it comprises less than 0.10 wt.-%, preferably less than 0.05 wt.-%, more preferably less than 0.01 wt.-% of other alpha-olefin monomers (e.g. C5 to C8 alpha-olefin monomer units).

[0076] Preferably, the propylene-ethylene elastomer (B) has a molecular weight distribution Mw / Mn in the range of 3.0 to 10.0, more preferably in the range of 4.0 to 8.0, most preferably in the range of 5.5 to 7.0. w / M n The ratio of weight average molecular weight Mw w to number average molecular weight Mn. n

[0077] Articles and applications The heterophasic polypropylene composition according to the present application can be prepared by any method known in the art. Ideally, a method is used which produces a homogeneous mixture of the various components. Usually compounding is employed. Compounding usually involves mixing or / and blending the various components in the molten state, usually by extrusion.

[0078] Preferably, the heterophasic polypropylene composition is prepared in a multi-stage process, wherein the propylene polymers are produced in sequential stages.

[0079] In a preferred embodiment, the heterophasic polypropylene composition according to any of the above embodiments is prepared in a multi-stage polymerization process, comprising: I) preparing a first propylene polymer fraction (A1) in a first polymerization stage in a bulk phase reactor, preferably a loop reactor, in the presence of a Ziegler-Natta catalyst, said first propylene polymer fraction (A1) being a propylene homopolymer or a propylene copolymer with ethylene comonomer units; ​II) transferring the first propylene polymer fraction (Al) to a second polymerization stage and producing a second propylene polymer fraction (A2) in a first gas phase reactor (GPR1) in the presence of a Ziegler-Natta catalyst, the second propylene polymer fraction (A2) being a propylene copolymer of propylene with comonomer units of ethylene and 1-butene; and wherein the first propylene polymer fraction (Al) and the second propylene polymer fraction (A2) together form a propylene copolymer (A); and III) transferring the propylene copolymer (A) to a third polymerization stage and producing a propylene ethylene elastomer (B) as a third propylene polymer fraction in a second gas phase reactor (GPR2) in the presence of a Ziegler-Natta catalyst, obtaining a heterophasic polypropylene composition.

[0080] The present application also relates to a process for producing a heterophasic polypropylene composition by a multi-stage polymerization process, the process comprising the above steps I), II) and III). The process can result in the heterophasic polypropylene composition of any of the above embodiments.

[0081] Thus, in step I) of the process, propylene and optionally ethylene are fed into a bulk phase reactor to produce a first propylene polymer fraction (Al).

[0082] In step II) of the process, propylene, 1-butene and ethylene are fed into a first gas phase reactor (GPR1) in which the first propylene polymer fraction (Al) has been previously placed to produce a second propylene polymer fraction (A2). These two propylene polymer fractions (Al) and (A2) form a propylene copolymer (A).

[0083] The propylene copolymer (A) is placed in a second gas phase reactor (GPR2) and in step III) of the process propylene, ethylene and optionally 1-butene are added to produce a heterophasic polypropylene composition. The process can further comprise blending the heterophasic composition with additives, and extruding and / or pelletizing the heterophasic composition.

[0084] Generally, the polymers produced in a multi-stage process are also referred to as "in situ" blends. The resulting final product is composed of a close mixture of polymers from three or more reactors. These three or more polymers can have different molecular weight distribution curves, and / or they can differ in comonomer content or type. Thus, the final product contains a mixture of three or more polymers with different properties, i.e. it is a multimodal polymer mixture.

[0085] The first polymerisation stage for producing the first propylene polymer fraction (A1) is preferably a slurry polymerisation step. Slurry polymerisation is typically carried out in a liquid mixture of the monomers used, preferably in the absence of an inert diluent, such as a hydrocarbon diluent.

[0086] The temperature of the first polymerisation stage is typically in the range of 60 to 100°C, preferably 60 to 80°C. Too high a temperature should be avoided to prevent partial dissolution of the polymer in the liquid phase, reactor fouling and premature deactivation of the catalyst. The pressure is typically in the range of 1 to 150 barg, preferably 40 to 80 barg.

[0087] Slurry polymerisation can be carried out in any known slurry polymerisation reactor, such as any bulk phase reactor. Such reactors include continuous stirred tank reactors and loop reactors. It is especially preferred to carry out the polymerisation in a loop reactor. In such reactors, the slurry is circulated at high speed through a closed pipe by the use of a circulation pump. Loop reactors are well known in the art, for example, examples are given in patent applications US-A-4582816, US-A-3405109, US-A-3324093, EP-A-479186 and US-A-5391654. It is therefore preferred to carry out the first polymerisation stage in a slurry polymerisation in a loop reactor.

[0088] The slurry can be withdrawn from the reactor continuously or intermittently. A preferred way of intermittent withdrawal is to use a settling leg, where the slurry is concentrated and then a batch of concentrated slurry is withdrawn from the reactor. The use of a settling leg is disclosed in US-A-3374211, US-A-3242150 and EP-A-1310295, among others. Continuous withdrawal methods have been disclosed in EP-A-891990, EP-A-1415999, EP-A-1591460 and WO-A-2007 / 025640, among others. Continuous withdrawal is preferably combined with a suitable concentration method, as disclosed in EP-A-1310295 and EP-A-1591460. It is preferred to continuously withdraw the slurry of the first polymerisation stage.

[0089] Hydrogen is typically introduced into the first polymerisation stage to control the MFR2of the polymer. The amount of hydrogen required to achieve the desired MFR2depends on the catalyst used and the polymerisation conditions, which will be appreciated by the skilled person.

[0090] The average residence time in the first polymerisation stage is typically in the range of 20 to 120 minutes, preferably 30 to 80 minutes. It is well known in the art that the average residence time The average residence time can be calculated by the following equation (2): Equation (2) wherein V RThis represents the volume of the reaction space (or the volume of the reactor if it is a loop reactor; or the volume of the fluidized bed if it is a fluidized bed reactor).

[0091] Q o This refers to the volumetric flow rate of the product stream (including polymer products and fluid reaction mixtures).

[0092] The production rate can be appropriately controlled by adjusting the catalyst feed rate. It can also be influenced by selecting a suitable monomer concentration. Then, the desired monomer concentration can be achieved by appropriately adjusting the propylene feed rate.

[0093] The first propylene polymer fraction (A1) is transferred to the second polymerization stage to prepare the second propylene polymer fraction (A2) in a gas-phase polymerization step (i.e., carried out in the 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.

[0094] For gas-phase reactors, the reaction temperature is typically 60 to 115°C (e.g., 70 to 110°C), the reactor pressure is typically 10 to 30 barg, and the residence time is typically 1 to 8 hours. The gas used is typically a non-reactive gas, such as nitrogen, or a low-boiling hydrocarbon, such as propane, that is present with the monomer.

[0095] Chain transfer agents (such as hydrogen) are typically added to the second polymerization stage.

[0096] 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, namely the propylene copolymer (A).

[0097] The propylene copolymer (A) is transferred to a third polymerization stage to produce propylene-ethylene elastomer (B) in 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, such as a fluidized bed gas-phase reactor. The conditions described above for the first gas-phase reactor also apply to the second gas-phase reactor.

[0098] The preferred multi-stage method is the aforementioned slurry-gas phase method, such as the Borstar® technology developed by Borealis. In this regard, reference can be made to European patent applications EP-A-0887379 and EP-A-0517868.

[0099] The method may include one or more further polymerization stages / steps. A pre-polymerization step is particularly preferred, which is performed before polymerization step I).

[0100] The purpose of prepolymerization is to polymerize a small amount of polymer onto the catalyst at low temperature and / or low monomer concentration. By prepolymerization, the performance of the catalyst in the slurry and / or the properties of the final polymer can be improved. The prepolymerization step is usually carried out in a slurry.

[0101] Thus, the prepolymerization step can be carried out in a loop reactor. The prepolymerization is also preferably carried out in liquid propylene and in the absence of an inert diluent, such as a hydrocarbon diluent.

[0102] The temperature in the prepolymerization step is usually from 0 to 60°C, preferably from 10 to 50°C, more preferably from 15 to 40°C.

[0103] The pressure is not critical and is usually from 1 to 150 barg, preferably from 40 to 80 barg.

[0104] The amount of monomer is usually such that from 0.1 to 1000 grams of monomer are polymerized per gram of solid catalyst component in the prepolymerization step. It is known to the skilled person that not all catalyst particles recovered from a continuous prepolymerization reactor contain the same amount of prepolymer. Instead, each particle has its own characteristic amount which depends on the residence time of the particle in the prepolymerization reactor. Since some particles reside in the reactor for a relatively long time and others for a relatively short time, the amount of prepolymer on different particles also varies and the amount of prepolymer contained in some individual particles can exceed the above limits. However, the average amount of prepolymer on the catalyst is usually within the above limits.

[0105] The molecular weight of the prepolymer can be controlled by hydrogen, which is known in the art. Furthermore, antistatic additives can be used to prevent the particles from adhering to each other or to the reactor wall, as disclosed in WO-A-96 / 19503 and WO-A-96 / 32420.

[0106] When a prepolymerization step is present, it is preferred to introduce the entire catalyst component into the prepolymerization step. However, when the solid catalyst component and the cocatalyst can be fed separately, it is possible to introduce only a part of the cocatalyst into the prepolymerization stage and the remaining part into the subsequent polymerization stage. In this case, it is necessary to introduce into the prepolymerization stage a sufficient amount of cocatalyst in which a sufficient polymerization reaction can be obtained.

[0107] It is understood that, within the scope of the present application, the amount of polymer produced in the prepolymerization is usually from 1.0 to 5.0 wt% based on the total weight of the heterophasic propylene composition. Said polymer is counted as part of the first propylene polymer fraction (A1).

[0108] The heterophasic polymer composition is preferably obtained by a polymerization process using a Ziegler-Natta catalyst. In a preferred embodiment, the Ziegler-Natta catalyst is used for all stages of the polymerization process.

[0109] Preferably, the Ziegler-Natta catalyst comprises: a) a compound of a transition metal of Group 4 to 6 according to IUPAC; b) a compound of a Group 2 metal; c) an internal donor, wherein the internal donor is a non-phthalic compound, preferably a non-phthalic acid ester; d) a cocatalyst; and e) optionally, an external donor.

[0110] The internal donor is preferably selected from the group consisting of (di)esters of non-phthalic carboxylic (di)acids, 1,3-diethers, derivatives thereof and mixtures thereof. Most preferably, the internal donor is a (di)ester of citraconic acid.

[0111] Preferably, the Ziegler-Natta catalyst does not comprise phthalate esters and the heterophasic polypropylene composition is free of phthalate esters and their corresponding decomposition products.

[0112] Ziegler-Natta catalysts suitable for the above polymerization reaction and methods for their preparation are described in EP-A-3562850.

[0113] It is understood that the propylene polymers can comprise standard polymer additives as described above.

[0114] After preparation, the resulting polymer is typically extruded and pelletized. The extrusion can be carried out in a manner generally known in the art, preferably in a twin-screw extruder. One example of a suitable twin-screw extruder is a co-rotating twin-screw extruder. These extruders are manufactured by Coperion or Japan Steel Works, among others. Another example is a counter-rotating twin-screw extruder. Such extruders are manufactured by Kobe Steel and Japan Steel Works, among others. Prior to extrusion, at least a portion of the desired additives as described above are preferably mixed with the polymer. The extruder typically comprises a melt section in which the polymer is melted and a mixing section in which the polymer melt is homogenized. Melting and homogenization are achieved by introducing energy into the polymer. Suitable specific energy input (SEI) levels are from about 150 to about 450 kWh / ton of polymer, preferably 175 to 350 kWh / ton.

[0115] Moulded articles The present invention also relates to an article comprising the multiphase polypropylene composition according to the invention in any of the above embodiments, and to the use of said multiphase polypropylene composition in articles. Preferred articles include films and molded articles.

[0116] The articles according to the present invention can be used in a variety of end applications, especially in food and non-food packaging applications and medical packaging applications.

[0117] The terminology used in this article Melt flow rate The term 'molded article' refers to an article produced using any conventional molding technique (e.g., injection molding, extrusion blow molding, stretch molding, compression molding, rotational molding, or injection stretch blow molding). Articles produced by injection molding, extrusion blow molding, or injection stretch blow molding are preferred. Articles produced by extrusion blow molding are particularly preferred. Preferably, the molded article is a thin-walled article with a wall thickness of 300 µm to 2 mm. More preferably, the wall thickness of the thin-walled article is 300 µm to 1400 µm, and even more preferably, the wall thickness of the thin-walled article is 500 µm to 900 µm. The molded article of the present invention can be a container, such as a bottle, jar, wide-mouth container, cylinder, etc.

[0118] The membrane can be prepared by any method known in the art, such as cast film extrusion or blown film extrusion, preferably the latter. The membrane can be a multilayer or a single-layer membrane, with its core layer composed of the multiphase polypropylene composition according to the invention. Preferably, the membrane is a non-oriented membrane. In one embodiment, the membrane is a single-layer membrane composed solely of the multiphase polypropylene composition according to the invention as the sole polymer component.

[0119] Generally, these products are characterized by moderate softness and can be used at higher temperatures (e.g., about 150°C).

[0120] Measurement methods All parameters mentioned in this specification or embodiments were measured according to the following method.

[0121] Quantitative description of the microstructure by nuclear magnetic resonance (NMR) spectroscopy Melt flow rate (MFR) is determined according to ISO 1133 and is expressed in g / 10 min. MFR is an indicator of polymer melt viscosity. The MFR of PE is determined at 190°C, and the MFR of PP is determined at 230°C. The load used to determine the melt flow rate is usually expressed as a subscript; for example, MFR2 is determined under a load of 2.16 kg (condition D).

[0122] Molecular weight and molecular weight distribution Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the comonomer content of polymers.

[0123] Use for 1H and 13 A Bruker Advance III 500 NMR spectrometer, operating at 500.13 and 125.76 MHz respectively, recorded quantitative data in the molten state. 13 C{ 1 HNMR spectroscopy. (Using...) 13 All spectra were recorded using a C-optimized 7 mm magic angle rotation (MAS) probe at 180 °C, with nitrogen used for all pneumatic devices. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconia MAS rotor and rotated at a frequency of 4 kHz. This setup was chosen primarily for the high sensitivity required for rapid identification and accurate quantification. Standard single-pulse excitation was used with a NOE of 3 s cycle delay and an RS-HEPT decoupling scheme. A total of 1024 (1 k) transients were acquired for each spectrum.

[0124] Quantitative 13 C{ 1 The H NMR spectra were processed, integrated, and the relevant quantitative characteristics were determined by integration. All chemical shifts were internally referenced to the methyl isotactic pentatonic group (mmmm) at 21.85 ppm and assigned according to {brandolini01,randall89, resconi00}.

[0125] Characteristic signals corresponding to 1-butene incorporation were observed, and comonomer content was quantified as follows. Taking into account the number of reporter sites for each comonomer, the concentration at 43.6 ppm was used. The amount of isolated 1-butene incorporated into the PBP sequence is quantified by the integral of the site:

[0126] If sequential incorporation of 1-butene is observed in the PBBP sequence, the number of reporter sites per comonomer is considered, using the value at 40.6 ppm. The amount of 1-butene continuously incorporated into the PBBP sequence is quantified by the integral of the site:

[0127] If there are continuously incorporated 1-butene (BB), the isolated incorporated butene (B) needs to be corrected by subtracting BB / 2 because of the influence signal.

[0128] Characteristic signals corresponding to different ethylene incorporations were observed, and the comonomer content was quantified using the following assignments and formulas for the corresponding sequences:

[0129] Based on Methylene sites, including The amount of uncoated additional propylene units, P, is quantified as:

[0130] The total amount of comonomer is then calculated as follows:

[0131]

[0132]

[0133]

[0134] The weight percent comonomer incorporation is calculated from the mol% as:

[0135]

[0136] For example, for xylene solubles where butene is not observed, the relevant equation simplifies to the following equation:

[0137] The total amount of comonomer is then calculated as follows:

[0138]

[0139]

[0140] The weight percent comonomer incorporation is calculated from the mol% as:

[0141] References klimke06: Klimke, K., Parkinson, M., Piel, C, Kaminsky, W., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382. parkinson07: Parkinson, M., Klimke, K., Spiess, H.W., Wilhelm, M.,Macromol. Chem. Phys. 2007;208:2128. pollard04: Pollard, M., Klimke, K., Graf, R., Spiess, H.W., Wilhelm,M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004;37:813. filip05: Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176,239 griffin07: Griffin, J.M., Tripon, C., Samoson, A., Filip, C., andBrown, S.P., Mag. Res. in Chem. 2007 45, S1, S198 castignolles09: Castignolles, P., Graf, R., Parkinson, M., Wilhelm,M., Gaborieau, M., Polymer 50 (2009) 2373 resconi00: Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem.Rev. 2000, 100, 1253 randall89: J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys.1989, C29, 201. brandolini01: A.J. Brandolini, D.D. Hills, “NMR spectra of polymersand polymer additives”, Marcel Deker Inc., 2000 abis86: L. Abis, Mackromol. Chem. 187, 1877-1886 (1986) Flexural modulus (FM) Molecular weight averages (M z , M w , and M n ), molecular weight distribution (MWD) and its breadth (described by polydispersity index, PDI = M w / M n , where M n is the number average molecular weight and M w is the weight average molecular weight) were 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 equations:

[0142] for a constant elution volume interval wherein and are the chromatographic peak slice area and the polyolefin molecular weight (MW) associated with the elution volume , respectively, where N equals the number of data points obtained from the chromatogram between the integration limits.

[0143] A high temperature GPC instrument equipped with an infra-red (IR) detector (IR4 or IR5) from PolymerChar (Valencia, Spain) or a differential refractometer (RI) from Agilent Technologies, and equipped with 3 x Agilent-PLgel Olexis and 1 x Agilent-PLgel Olexis Guard columns was used. 1,2,4-Trichlorobenzene (TCB) stabilized with 250 mg / L 2,6-di tert butyl-4-methyl-phenol was used as solvent and mobile phase. The chromatographic system was run at 160 °C at a constant flow rate of 1 mL / min. 200 μL of sample solution were injected per analysis. Data collection was performed using Agilent Cirrus Software version 3.3 or PolymerChar GPC-IR control software.

[0144] The column set was calibrated using a universal calibration method (according to ISO 16014-2:2003) with 19 narrow molecular weight distribution (MWD) polystyrene (PS) standards in the range of 0.5 kg / mol to 11500 kg / mol. The PS standards were dissolved in tetrahydrofuran (THF) at room temperature for several hours. The polystyrene peak molecular weights were converted to polyolefin molecular weights using the Mark Houwink equation and the following Mark Houwink constants:

[0145] The calibration data were fitted using a third-order polynomial.

[0146] All samples were prepared at concentrations ranging from 0.5 to 1 mg / ml and dissolved at 160°C with gentle shaking for 2.5 hours (PP) or 3 hours (PE).

[0147] Glass transition temperature (T The flexural modulus was determined according to ISO 178 at 23°C using a three-point bending test on an 80x10x4 mm injection molded according to ISO 1873-2. 3 Determined on the test bar.

[0148] Differential scanning calorimetry (DSC) g ) The glass transition temperature T was determined by dynamic mechanical analysis according to ISO 6721-7. g1 and T g2 .

[0149] The measurement was performed on a compression-molded sample (40x10x1 mm). 3 The heating is performed in a torsion mode, with a temperature range of -100℃ to +150℃, a heating rate of 2℃ / min, and a frequency of 1 Hz.

[0150] Notched impact strength (NIS) Differential scanning calorimetry (DSC) analysis was performed on 5 to 7 mg samples using a TA Instrument Q200 differential scanning calorimeter (DSC) to measure the melting temperature (T). m ), enthalpy of fusion (H) m The crystallization temperature (Tc) was measured. DSC was performed according to ISO 11357 / Part 3 / Method C2 using a heating / cooling / heating cycle at a scan rate of 10 °C / min, covering a temperature range of -30 to +225 °C. c The melting temperature (T) is determined by the cooling step. m ) and enthalpy of fusion (H m The value is determined by the second heating step.

[0151] In this specification, the term T m This should be understood as the peak melting temperature determined by DSC at a heating rate of 10 K / min.

[0152] In this specification, the term T c This should be understood as the peak crystallization temperature determined by DSC at a cooling rate of 10 K / min.

[0153] Xylene solubles (XS) and xylene insolubles (XI) Charpy notched impact strength (NIS) was measured at +23°C according to ISO 179 1eA using an 80x10x4 mm gauge prepared according to ISO 1873-2. 3 Injection-molded rod-shaped specimen.

[0154] Intrinsic viscosity (IV) The xylene soluble (XS) and xylene insoluble (XI) were determined at 25°C according to ISO 16152.

[0155] Preparation of heterophasic polypropylene composition IV of xylene solubles in decahydronaphthalene at 135 °C, according to ISO 1628-1&3.

[0156] Example Properties of heterophasic polypropylene composition In the multi-stage polymerization method described above, two multiphase polypropylene compositions according to the present invention were prepared under the conditions shown in Table 1, as Examples IE1 and IE2 of the present invention. The catalyst was a Ziegler-Natta catalyst, the preparation method of which is described in EP-A-3562850. The solid catalyst component was used in conjunction with triethylaluminum (TEAL) (as a co-catalyst) and dicyclopentyldimethoxysilane (D-donor) (as an external donor).

[0157] Furthermore, the preparation methods of comparative examples CE1 and CE2 are shown in Table 1. The number of stages in the preparation methods of the comparative examples is the same as the number of stages in the preparation methods of the embodiments of the present invention. However, the comparative examples are random multiphase copolymers containing only propylene and ethylene.

[0158] Table 1: Process Conditions

[0159] The above prepared polymer was mixed with 0.25 wt% of Irganox B215 (a synergistic 2:1 mixture of Irgafos 168 (tris(2,4-di-tert-butylphenyl) phosphite, CAS No: 31570-04-4) and Irganox 1010 (pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4- hydroxyphenyl]propionate], CAS No: 6683-19-8), commercially available from BASF SE, Germany) and 0.05 wt% of CEASIT FI (calcium stearate, CAS No: 1592-23-0, commercially available from Baerlocher GmbH, Germany) and then compounded in a twin-screw extruder ZSK 18 with a melt temperature of 200-220 °C and a production rate of 7 kg / h. The polymer was pelletized with or without nucleating agents (as shown in Table 2).

[0160] ​ The properties of the polymer compositions (prepared into pellets) were measured and summarized in Table 2 below.

[0161] Table 2: Properties of the polymer compositions

[0162] * IE2 contains 1000 ppm of ADK STAB NA-71 (purchased from Adeka, France) as a nucleating agent.

[0163] ** CE2 was prepared using Nordic Chemical Nucleation Technology (BNT), see EP 2960279 for details.

[0164] The inventive examples have high melt temperature above 160 °C, while the comparative examples have a melt temperature 15 to 20 °C lower. All examples have a flexural modulus in the moderate softness range, with the inventive examples being softer. The inventive examples have improved Charpy notched impact strength.

Claims

1. A multiphase polypropylene composition comprising a propylene copolymer (A) matrix of propylene, ethylene, and 1-butene comonomer units, and a propylene-ethylene elastomer (B) dispersed in said matrix, said multiphase polypropylene composition comprising Based on the total weight of the multiphase polypropylene composition and determined according to ISO 16152 at 25°C, 25 to 50% by weight of xylene-soluble (XS), the xylene-soluble comprising propylene comonomer units and, based on the total weight of the xylene-soluble (XS), 18.0 to 35.0% by weight of ethylene comonomer units, and the xylene-soluble (XS) having an intrinsic viscosity IV of 1.8 to 3.0 dl / g as determined according to ISO 1628-1 & 3; and Wherein based on the total weight of the multiphase polypropylene composition and by 13 C-NMR spectroscopy determined that the multiphase polypropylene composition comprises 1-butene comonomer units in the range of 3.0 to 10.0 wt% and ethylene comonomer units in the range of 5.0 to 15.0 wt%; and wherein the multiphase polypropylene has: i) the melt flow rate MFR2 determined according to ISO 1133 at 230 °C in the range of 0.1 to 20.0 g / 10 min; and ii) The melting temperature T, determined by differential scanning calorimetry (DSC) as described in the specification, within the range of 157 to 170°C. m .

2. The multiphase polypropylene composition according to claim 1, wherein the multiphase polypropylene composition has a first glass transition temperature Ti as determined according to ISO 6721-7 in the range of -12 to +2°C. g1 And the second glass transition temperature T in the range of -55 to -35°C g2 .

3. The multiphase polypropylene composition according to any one of the preceding claims, wherein the multiphase polypropylene composition has a flexural modulus determined according to ISO 178 in the range of 300 to 700 MPa.

4. The multiphase polypropylene composition according to any one of the preceding claims, wherein the multiphase polypropylene composition has a strength of 65.0 to 120.0 kJ / m³. 2 Impact strength at +23°C within the range determined according to ISO 179 / 1eA.

5. The multiphase polypropylene composition according to any one of the preceding claims, wherein the crystallization temperature Tc of the multiphase polypropylene composition, determined by differential scanning calorimetry (DSC) as described in the specification, is 115 to 125°C for non-nucleating multiphase polypropylene compositions and / or 121 to 135°C for nucleating multiphase polypropylene compositions.

6. The multiphase polypropylene composition according to any one of the preceding claims, wherein the multiphase polypropylene composition is free of phthalates and their respective decomposition products.

7. The multiphase polypropylene composition according to any one of the preceding claims, wherein the propylene copolymer (A) is a multimodal propylene copolymer, and / or the propylene ethylene elastomer (B) is a unimodal propylene copolymer.

8. The multiphase polypropylene composition according to any one of the preceding claims, wherein, based on the total weight of the multiphase polypropylene composition, the multiphase polypropylene composition comprises 75 to 90% by weight of a propylene copolymer (A) and 10 to 25% by weight of a propylene ethylene elastomer (B).

9. The multiphase polypropylene composition according to any one of the preceding claims, wherein the propylene copolymer (A) comprises two different propylene polymer fractions: a) Based on the total weight of the propylene copolymer (A), 30 to 70% by weight of a first propylene polymer fraction (A1), wherein the first propylene polymer fraction (A1) is a propylene homopolymer or a propylene copolymer of propylene and ethylene comonomer units, preferably a propylene homopolymer; and b) Based on the total weight of the propylene copolymer (A), 30 to 70% by weight of a second propylene polymer fraction (A2), the second propylene polymer fraction (A2) being a propylene copolymer of propylene and ethylene comonomer units and 1-butene comonomer units.

10. The multiphase polypropylene composition according to any one of the preceding claims, wherein the composition is based on the total weight of the propylene copolymer (A) and is determined by... 13 C-NMR spectroscopy determined that the propylene copolymer (A) contains 1-butene comonomer units in the range of 2.0 to 6.0% by weight and ethylene comonomer units in the range of 1.0 to 3.9% by weight.

11. A method for preparing the multiphase polypropylene composition according to any one of the preceding claims by a multi-stage polymerization method, comprising: I) In the presence of a Ziegler-Natta catalyst, during the first polymerization stage, in a bulk reactor, preferably a loop reactor, a first propylene polymer fraction (A1) is prepared, wherein the first propylene polymer fraction (A1) is a propylene homopolymer or a propylene copolymer of propylene and ethylene comonomer units. II) The first propylene polymer fraction (A1) is transferred to the second polymerization stage, and a second propylene polymer fraction (A2) is prepared in a first gas-phase reactor (GPR1) in the presence of a Ziegler-Natta catalyst. The second propylene polymer fraction (A2) is a propylene copolymer of propylene with ethylene comonomer units and 1-butene comonomer units; and The first propylene polymer fraction (A1) and the second propylene polymer fraction (A2) together form a propylene copolymer (A); and III) The propylene copolymer (A) is transferred to the third polymerization stage, and in the second gas phase reactor (GPR2), a propylene-ethylene elastomer (B) as the third propylene polymer fraction is prepared in the presence of a Ziegler-Natta catalyst to obtain a multiphase polypropylene composition.

12. The method of claim 11, wherein the Ziegler-Natta catalyst comprises: a) Compounds of IUPAC group 4 to 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-phthalic acid ester; d) Co-catalysts; and e) Optionally, external donor.

13. The method according to claim 12, wherein the internal donor is preferably selected from the (di) esters of non-phthalic acid (di)carboxylic acids, 1,3-diethers, derivatives thereof, and mixtures thereof.

14. An article comprising a multiphase polypropylene composition according to any one of claims 1 to 10, preferably a film or a molded article.

15. The use of the multiphase polypropylene composition according to any one of claims 1 to 10 in articles, preferably in films or molded articles.

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