Polypropylene composition suitable for foaming injection molding products

Abstract

The present invention relates to a polypropylene composition comprising from 55.0 to 97.5% by weight of a heterophasic propylene copolymer (A), from 2.5 to 25.0% by weight of a high melt strength propylene homopolymer (B) and from 0 to 20.0% by weight of a copolymer of ethylene with at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms, the invention relates to a polypropylene composition, to an injection molded article comprising said polypropylene composition, to a foamed article comprising said polypropylene composition and to the use of said polypropylene composition for producing a foamed article.

Description

Technical Field

[0001] The present invention relates to a polypropylene composition comprising 55.0 to 97.5 wt.% of a heterophasic propylene copolymer (A), 2.5 to 25.0 wt.% of a high melt strength propylene homopolymer (B) and 0 to 20.0 wt.% of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, an injection molded article comprising the polypropylene composition, a foamed article comprising the polypropylene composition and use of the polypropylene composition for producing a foamed article. Background Art

[0002] Plastic materials characterized by reduced weight while maintaining a mechanical property profile are receiving increasing attention, for example in the automotive and packaging industries. Therefore, low-density parts can be produced using foam injection-moulding technology.

[0003] Especially in the automotive industry, an established method for preparing foam injection molded parts is core back injection molding. Thus, a polymer composition (such as a polypropylene composition) is melted and injected into a mold together with a blowing agent. Then, the mold filled with the composition is opened to a predetermined degree, which activates the blowing agent and introduces bubbles into the injected composition. Typically, when using core back foam injection molding technology (core-back foam injection molding technology, also known as core back foam injection molding technology), the density reduction achieved is already as high as 30%, because a higher density reduction can lead to a deteriorated foam structure and foam performance. The limited maximum density reduction limits the applicability of this technology in other applications where a higher density reduction is required. For example, a beverage cup for repeated use of hot and / or cold drinks can be mentioned.

[0004] High foaming degree can not only reduce the density of the foamed product, but also bring other desirable properties, such as improved thermal insulation. In addition to low density, the final product also needs to show good surface quality and sufficient mechanical properties to be used in the target application. In many cases, especially in the case of high density reduction, the foamed product does not have sufficient toughness, and the usability of the foamed product is limited due to the brittleness of the final product.

[0005] Therefore, there is a need for a polypropylene composition which can be used to produce foamed injection molded articles having a high density reduction and an improved balance of properties in terms of toughness and stiffness.

[0006] The present invention provides a polypropylene composition which, when foamed in the presence of a blowing agent, provides a foamed article having a surprisingly improved balance of properties of low density, high toughness (determined by high puncture energy) and high stiffness (determined by high flexural modulus) and high tensile properties. Summary of the invention

[0007] The present invention relates to a polypropylene composition comprising

[0008] (A) 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-%, based on the total weight of the composition, of a heterophasic propylene copolymer comprising a matrix phase and an elastomeric phase dispersed in said matrix phase and having a xylene cold soluble (XCS) fraction in an amount of 10.0 to 25.0 wt.-%, preferably 11.5 to 22.5 wt.-%, more preferably 12.5 to 20.0 wt.-%, based on the total amount of heterophasic propylene copolymer (A);

[0009] (B) 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-%, based on the total weight of the composition, of a high melt strength propylene homopolymer having a melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg, of 0.5 to 5.0 g / 10 min, preferably 1.0 to 3.0 g / 10 min and more preferably 1.2 to 2.5 g / 10 min;

[0010] (C) 0 to 20.0 wt. %, preferably 0 to 15.0 wt. %, more preferably 0 to 12.5 wt. % of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, based on the total weight of the composition, the copolymer having a molecular weight of 860 to 880 kg / m 3 , preferably 862 to 877 kg / m 3 , more preferably 865 to 875 kg / m 3 A density determined according to ISO 1183 of 0.1 to 2.5 g / 10 min, preferably 0.2 to 2.0 g / 10 min, more preferably 0.5 to 1.5 g / 10 min, determined according to ISO 1133 at a temperature of 190° C. and a load of 2.16 kg.

[0011] According to a preferred embodiment of the present invention, there is provided a polypropylene composition having a melt flow rate MFR2 of 10.0 to 55.0 g / 10 min as measured at a temperature of 230° C. and a load of 2.16 kg according to ISO 1133, the polypropylene composition comprising

[0012] (A) 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-%, based on the total weight of the composition, of a heterophasic propylene copolymer comprising a matrix phase and an elastomeric phase dispersed in said matrix phase and having a xylene cold soluble (XCS) fraction in an amount of 10.0 to 25.0 wt.-%, preferably 11.5 to 22.5 wt.-%, more preferably 12.5 to 20.0 wt.-%, based on the total amount of heterophasic propylene copolymer (A);

[0013] (B) 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-%, based on the total weight of the composition, of a high melt strength propylene homopolymer having a melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg, of 0.5 to 5.0 g / 10 min, preferably 1.0 to 3.0 g / 10 min and more preferably 1.2 to 2.5 g / 10 min;

[0014] (C) 0 to 20.0 wt. %, preferably 0 to 15.0 wt. %, more preferably 0 to 12.5 wt. % of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, based on the total weight of the composition, the copolymer having a molecular weight of 860 to 880 kg / m 3 , preferably 862 to 877 kg / m 3 , more preferably 865 to 875 kg / m 3 A density determined according to ISO 1183 of 0.1 to 2.5 g / 10 min, preferably 0.2 to 2.0 g / 10 min, more preferably 0.5 to 1.5 g / 10 min, determined according to ISO 1133 at a temperature of 190° C. and a load of 2.16 kg.

[0015] Further, the present invention relates to an injection moulded article comprising the polypropylene composition as described above or below.

[0016] Still further, the present invention relates to a foamed article, preferably a foamed injection moulded article, comprising the polypropylene composition as described above or below.

[0017] Finally, the present invention relates to the use of a polypropylene composition and a blowing agent as described above or below for producing a foamed article, preferably a foamed injection moulded article.

[0018] definition

[0019] Heterophasic polypropylene is a propylene-based copolymer having a crystalline matrix phase and an elastomeric phase dispersed therein, the crystalline matrix phase being a propylene homopolymer or a random copolymer of propylene and at least one α-olefin comonomer. In the case of a random heterophasic propylene copolymer, the crystalline matrix phase is a random copolymer of propylene and at least one α-olefin comonomer.

[0020] The elastomeric phase may be a propylene copolymer with a high amount of comonomer which is not randomly distributed in the polymer chain but is distributed in comonomer-rich block structures and propylene-rich block structures. Heterophasic polypropylene generally differs from monophasic propylene copolymers as it shows two different glass transition temperatures Tg, which are attributed to the matrix phase and the elastomeric phase.

[0021] The expression "propylene homopolymer" relates to a polypropylene consisting essentially of propylene units, i.e. a polypropylene consisting of at least 99.0 wt.-%, more preferably at least 99.5 wt.-%, still more preferably at least 99.8 wt.-%, such as at least 99.9 wt.-% propylene units. In another embodiment, only propylene units are detectable, i.e. only propylene has been polymerized.

[0022] Propylene random copolymers are copolymers of propylene monomer units and comonomer units, wherein the comonomer units are randomly distributed on the polymer chain. Propylene random copolymers may contain comonomer units from one or more comonomers having different numbers of carbon atoms. Propylene random copolymers do not contain an elastomeric phase.

[0023] Ethylene copolymers are copolymers of ethylene monomer units and comonomer units. Thus, the ethylene monomer units account for the molar majority of the ethylene copolymer, i.e., more than 50 mole % of the ethylene copolymer.

[0024] Plastomers are polymers that combine the properties of elastomers and plastics, such as rubber-like performance and the processing capabilities of plastics.

[0025] Vinyl plastomers are plastomers whose molar majority is ethylene monomer units.

[0026] If not stated otherwise, percentages herein are generally given as % by weight (wt.-%). DETAILED DESCRIPTION

[0027] Polypropylene composition

[0028] In one aspect, the present invention is directed to a polypropylene composition.

[0029] The polypropylene composition comprises as polymer components 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-% of a heterophasic propylene copolymer (A), 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-% of a high melt strength propylene homopolymer (B) and 0 to 20.0 wt.-%, preferably 0 to 15.0 wt.-%, more preferably 0 to 12.5 wt.-% of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, all amounts based on the total weight of the polypropylene composition.

[0030] The polypropylene composition may comprise further polymer components different from components (A), (B) and (C) in an amount of up to 10 wt%.

[0031] However, it is preferred that the polymer component of the polypropylene composition consists of components (A), (B) and optionally (C).

[0032] The polymer components, preferably components (A), (B) and optionally (C) preferably comprise 80.0 to 100 wt.-% of the polypropylene composition, more preferably 85.0 to 99.999 wt.-% of the polypropylene composition, still more preferably 97.5 to 99.99 wt.-% of the polypropylene composition.

[0033] The polypropylene composition may further comprise an inorganic filler in an amount of 0 to 20.0 wt.-%, preferably 0 to 15.0 wt.-%, based on the total weight of the polypropylene composition.

[0034] Preferably, the inorganic filler is a mineral filler. It is understood that the inorganic filler is a phyllosilicate, mica or wollastonite. Even more preferably, the inorganic filler is selected from the group consisting of mica, wollastonite, kaolinite, smectite, montmorillonite and talc. Most preferably, the inorganic filler is talc and / or wollastonite.

[0035] However, it is preferred that the polypropylene composition comprises no inorganic fillers.

[0036] Further, the polypropylene composition can include an additive of 0 to 10.0 % by weight, preferably 0.001 to 5.0 % by weight, more preferably 0.01 to 3.5 % by weight, based on the gross weight of the polypropylene composition. Typical additives are acid scavengers, antioxidants, colorants, light stabilizers, plasticizers, slip agents, anti-scratch agents, dispersants, processing aids, lubricants, pigments, etc. Optional inorganic fillers are not considered as additives. Such additives are commercially available, and are described, for example, in " Plastic Additives Handbook " by Hans Zweifel, 2009, the 6th edition (pages 1141 to 1190).

[0037] The polypropylene composition preferably has a molecular weight of 890 to 1100 kg / m 3 density.

[0038] Therefore, the density depends on the presence of inorganic fillers.

[0039] If no inorganic filler is present, the polypropylene composition preferably has a carbon content of 890 to 915 kg / m 3 , more preferably 895 to 910 kg / m 3 density.

[0040] In the presence of inorganic fillers, the polypropylene composition may have a weight up to 1100 kg / m 3 density.

[0041] Further, the polypropylene composition preferably has a melt flow rate MFR2 measured according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg of 10.0 to 55.0 g / 10 min, preferably 15.0 to 50.0 g / 10 min, more preferably 17.0 to 45.0 g / 10 min.

[0042] The polypropylene composition preferably shows a good balance of properties in terms of stiffness and toughness. This can preferably be seen in the following properties:

[0043] The polypropylene composition preferably has a flexural modulus of 1200 to 2000 MPa, more preferably of 1300 to 1850 MPa, still more preferably of 1400 to 1750 MPa.

[0044] Furthermore, the polypropylene composition preferably has a maximum force at 23°C of 1750 to 2750 N, more preferably of 2000 to 2600 N, still more preferably of 2100 to 2500 N.

[0045] Furthermore, the polypropylene composition preferably has an Energy to Max Force at 23°C of 10 to 20 J, more preferably of 12 to 18 J, still more preferably of 13 to 17 J.

[0046] Further, the polypropylene composition preferably has a puncture energy at 23°C of 15 to 35 J, more preferably of 18 to 32 J, still more preferably of 20 to 30 J.

[0047] Still further, the polypropylene composition preferably has a tensile modulus of 1200 to 2000 MPa, more preferably of 1300 to 1850 MPa, still more preferably of 1400 to 1800 MPa.

[0048] Furthermore, the polypropylene composition preferably has a tensile strain at break of 10 to 75%, more preferably of 12 to 70%, still more preferably of 15 to 60%.

[0049] Furthermore, the polypropylene composition preferably has a tensile strain at tensile strength of 2.0 to 7.5%, more preferably of 2.5 to 7.0%, still more preferably of 3.0 to 6.5%.

[0050] Further, the polypropylene composition preferably has a tensile strain at yield of 2.0 to 7.5%, more preferably of 2.5 to 7.0%, still more preferably of 3.0 to 6.5%.

[0051] Still further, the polypropylene composition preferably has a tensile strength of 15 to 50 MPa, more preferably of 20 to 45 MPa, still more preferably of 23 to 40 MPa.

[0052] Furthermore, the polypropylene composition preferably has a tensile stress at break of 10 to 35 MPa, more preferably of 13 to 30 MPa, still more preferably of 15 to 25 MPa.

[0053] Further, the polypropylene composition preferably has a tensile stress at yield of 15 to 50 MPa, more preferably of 20 to 45 MPa, still more preferably of 23 to 40 MPa.

[0054] The polypropylene composition can have a specific branching index according to the GPC-VISC-MALS analysis. In this article, the GPC-VISC-MALS analysis can be carried out as described in "Measuring Method" part of the present disclosure below. The polypropylene composition of melt blending form can be used to carry out GPC-VISC-MALS analysis. The branching index according to the GPC-VISC-MALS analysis may be relevant to the amount of the high melt strength propylene homopolymer (B) present in the polypropylene composition. Therefore, the branching index can also be used to determine the amount of high melt strength propylene homopolymer (B).

[0055] The polypropylene composition may have a branching index determined according to GPC-VISC-MALS analysis in the range of 0.01 to 0.45, preferably in the range of 0.01 to 0.40, more preferably in the range of 0.02 to 0.38, like in the range of 0.03 to 0.35 or in the range of 0.04 to 0.32.

[0056] The polypropylene composition is preferably produced by melt blending components (A), (B), optional component (C) and further optional components as described above in a compounding device such as an extruder. A suitable extruder is for example a twin-screw extruder. Compounding conditions are generally known in the art.

[0057] Heterophasic propylene copolymer (A)

[0058] The polypropylene composition comprises the heterophasic propylene copolymer (A) in an amount of 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-%, based on the total weight of the composition.

[0059] The heterophasic propylene copolymer (A) comprises a matrix phase and an elastomeric phase dispersed in the matrix phase.

[0060] The heterophasic propylene copolymer (A) has a xylene cold soluble (XCS) fraction in an amount of 10.0 to 25.0 wt.-%, preferably 11.5 to 22.5 wt.-%, more preferably 12.5 to 20.0 wt.-%, based on the total amount of heterophasic propylene copolymer (A).

[0061] The xylene cold soluble fraction (XCS) of the heterophasic propylene copolymer (A) preferably has an intrinsic viscosity (IV(XCS)) in the range of 2.00 to 4.00 dl / g, more preferably in the range of 2.30 to 3.70 dl / g, still more preferably in the range of 2.50 to 3.40 dl / g, most preferably in the range of 2.70 to 3.30 dl / g.

[0062] The xylene cold soluble fraction (XCS) of the heterophasic propylene copolymer (A) preferably has an ethylene content (C2(XCS)) measured during CRYSTEX analysis by infrared spectroscopy in the range of 20.0 to 60.0 wt.-%, more preferably in the range of 25.0 to 50.0 wt.-%, still more preferably in the range of 30.0 to 45.0 wt.-%, most preferably in the range of 32.5 to 40.0 wt.-%.

[0063] The heterophasic propylene copolymer (A) preferably has a crystalline fraction (CF) determined according to CRYSTEX QC method ISO 6427-B present in an amount in the range of 72.5 to 92.0 wt.-%, more preferably in the range of 75.0 to 90.0 wt.-%, still more preferably in the range of 77.5 to 88.0 wt.-%, most preferably in the range of 80.0 to 87.5 wt.-% relative to the total weight of the heterophasic propylene copolymer (A).

[0064] The crystalline fraction (CF) of the heterophasic propylene copolymer (A) preferably has an intrinsic viscosity (IV(CF)) in the range of 0.90 to 2.00 dl / g, more preferably in the range of 1.00 to 1.80 dl / g, still more preferably in the range of 1.05 to 1.60 dl / g, most preferably in the range of 1.10 to 1.50 dl / g.

[0065] The crystalline fraction (CF) of the heterophasic propylene copolymer (A) preferably has an ethylene content (C2(CF)) measured during CRYSTEX analysis by infrared spectroscopy in the range of 0.5 to 5.0 wt.-%, more preferably in the range of 1.0 to 4.0 wt.-%, still more preferably in the range of 1.3 to 3.0 wt.-%, most preferably in the range of 1.5 to 2.0 wt.-%.

[0066] The heterophasic propylene copolymer (A) preferably has a soluble fraction (SF) determined according to CRYSTEX QC method ISO 6427-B present in an amount in the range of 8.0 to 27.5 wt.-%, more preferably in the range of 10.0 to 25.0 wt.-%, still more preferably in the range of 12.0 to 22.5 wt.-%, most preferably in the range of 12.5 to 20.0 wt.-% relative to the total weight of the heterophasic propylene copolymer (A).

[0067] The soluble fraction (SF) of the heterophasic propylene copolymer (A) preferably has an intrinsic viscosity (IV(SF)) in the range of 1.80 to 4.00 dl / g, more preferably in the range of 2.00 to 3.50 dl / g, still more preferably in the range of 2.20 to 3.50 dl / g, most preferably in the range of 2.40 to 3.30 dl / g.

[0068] The soluble fraction (SF) of the heterophasic propylene copolymer (A) preferably has an ethylene content (C2(SF)) measured during CRYSTEX analysis by infrared spectroscopy in the range of 20.0 to 60.0 wt.-%, more preferably in the range of 22.5 to 50.0 wt.-%, still more preferably in the range of 25.0 to 45.0 wt.-%, most preferably in the range of 30.0 to 40.0 wt.-%.

[0069] The ratio of the intrinsic viscosity of the soluble fraction to the intrinsic viscosity of the crystalline fraction (IV(SF) / IV(CF)) of the heterophasic propylene copolymer (A) is preferably in the range of 1.00 to 3.00, more preferably in the range of 1.30 to 2.70, still more preferably in the range of 1.60 to 2.50, most preferably in the range of 1.80 to 2.40.

[0070] The heterophasic propylene copolymer (A) preferably consists of propylene monomer units and ethylene monomer units.

[0071] The heterophasic propylene copolymer (A) preferably has a total ethylene content (C2) measured in the range of 3.0 to 15.0 wt.-%, more preferably in the range of 4.0 to 12.0 wt.-%, still more preferably in the range of 5.0 to 10.0 wt.-%, most preferably in the range of 6.0 to 8.5 wt.-%.

[0072] The heterophasic propylene copolymer (A) preferably has a melt flow rate MFR2 measured according to ISO 1133-1 at 230 °C under a load of 2.16 kg in the range of 15.0 to 100.0 g / 10 min, more preferably in the range of 20.0 to 90.0 g / 10 min, still more preferably in the range of 25.0 to 85.0 g / 10 min, most preferably in the range of 30.0 to 80.0 g / 10 min.

[0073] The heterophasic propylene copolymer (A) may be polymerized via processes well known in the art or alternatively may be a commercially available polypropylene grade. It is understood that commercially available grades may contain common additives.

[0074] In one embodiment the heterophasic propylene copolymer (A) consists of a single heterophasic propylene copolymer.

[0075] In said embodiment the single heterophasic propylene copolymer (A) preferably has a melt flow rate MFR2 measured according to ISO 1133-1 at 230 °C under a load of 2.16 kg in the range of 15.0 to 55.0 g / 10 min, more preferably in the range of 20.0 to 50.0 g / 10 min, still more preferably in the range of 25.0 to 47.0 g / 10 min, most preferably in the range of 30.0 to 45.0 g / 10 min.

[0076] In another embodiment the heterophasic propylene copolymer (A) comprises, preferably consists of, two or more, such as two to five, preferably two or three, most preferably two, heterophasic propylene copolymers (A-1) and (A-2).

[0077] The heterophasic propylene copolymers (A-1 ) and (A-2) differ in their melt flow rate MFR2. Thus, the heterophasic propylene copolymer (A-1 ) has a lower melt flow rate MFR2 than the heterophasic propylene copolymer (A-2).

[0078] The heterophasic propylene copolymer (A-1 ) preferably has a melt flow rate MFR2 measured according to ISO 1133-1 at 230 °C under a load of 2.16 kg in the range of 15.0 to 55.0 g / 10 min, more preferably in the range of 20.0 to 50.0 g / 10 min, still more preferably in the range of 25.0 to 47.0 g / 10 min, most preferably in the range of 30.0 to 45.0 g / 10 min.

[0079] The heterophasic propylene copolymer (A-2) preferably has a melt flow rate MFR2 measured according to ISO 1133-1 at 230 °C under a load of 2.16 kg in the range of more than 55.0 to 100.0 g / 10 min, such as in the range of 57.0 to 100.0 g / 10 min, more preferably in the range of 60.0 to 90.0 g / 10 min, still more preferably in the range of 62.5 to 85.0 g / 10 min, most preferably in the range of 65.0 to 80.0 g / 10 min.

[0080] The weight ratio of heterophasic propylene copolymer (A-1) to heterophasic propylene copolymer (A-2) in the polypropylene composition is preferably in the range of 40:60 to 60:40, more preferably in the range of 45:55 to 55:45.

[0081] The heterophasic propylene copolymer (Al) is preferably present in the polypropylene composition in an amount of 25.0 to 55.0 wt.-%, more preferably 30.0 to 54.0 wt.-%, still more preferably 32.5 to 52.5 wt.-%, based on the total weight of the polypropylene composition.

[0082] The heterophasic propylene copolymer (A-2) is preferably present in the polypropylene composition in an amount of 25.0 to 55.0 wt.-%, more preferably 30.0 to 54.0 wt.-%, still more preferably 32.5 to 52.5 wt.-%, based on the total weight of the polypropylene composition.

[0083] High melt strength propylene homopolymer (B)

[0084] The polypropylene composition comprises the high melt strength propylene homopolymer in an amount of 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-%, based on the total weight of the composition.

[0085] High melt strength propylene polymer is branched, therefore, it is different from linear propylene polymer in that the polypropylene main chain covers side chains, while non-branched propylene polymer (i.e. linear propylene polymer) does not cover side chains. Side chains have a significant effect on the rheological properties of propylene polymer. Therefore, linear propylene polymers and high melt strength propylene polymers can be clearly distinguished by their flow behavior under stress (e.g., polymer melt viscosity ratio measured under different loads). Additionally or alternatively, long chain branching can be determined by NMR analysis of the content of long chain branching and / or by measuring the long chain branching index g' using, for example, SEC / VISC-LS (size exclusion chromatography / viscometry-light scattering) known in the art. Branching index g' is a parameter of the degree of branching. Branching index g' is related to the amount of branching of the polymer. Low g' values ​​are indicators of highly branched polymers. In other words, if the g' value decreases, the branching of polypropylene will increase. For example, at least 0.96, such as at least 0.97 or at least 0.98 g' value generally indicates that long chain branching does not exist. On the other hand, 0.9 or less (e.g., 0.6 to 0.9), such as 0.8 or lower g' value generally indicates that polymer contains long chain branching. More details about branching index g' and its determination method are described, for example, in the "Measuring Method" section of EP3280748B1, which is incorporated herein by reference. The branching index g' measured using SEC / VISC-LS analysis is different from the branching index measured using GPC-VISC-MALS analysis, as described herein above and below in conjunction with the polypropylene composition according to an embodiment of the present invention.

[0086] Branching can usually be achieved by using a specific catalyst (i.e. a specific single active site catalyst), or by chemical modification. Regarding the preparation of the branched propylene polymer obtained by using a specific catalyst, reference is made to EP 1 892264. Regarding the branched propylene polymer obtained by chemical modification, reference is made to EP 0 787 750, EP 0 879 830 A1 and EP 0890 612A2. In this case, branched propylene polymers are also referred to as high melt strength propylene polymers. High melt strength propylene homopolymer (B) is preferably obtained by chemical modification of the propylene polymer as described in more detail below. High melt strength propylene homopolymer can be obtained under the trade name Daploy TM Commercially available from Borealis AG.

[0087] In case the high melt strength propylene homopolymer (B) is a high melt strength propylene homopolymer obtained by chemical modification of a linear propylene homopolymer, the definition of propylene homopolymer is understood to mean a linear propylene homopolymer used for obtaining the high melt strength propylene homopolymer (B) by chemical modification, e.g. with bifunctionally unsaturated monomer(s) and / or multifunctionally unsaturated low molecular weight polymer(s) in reactive extrusion.

[0088] High melt strength propylene homopolymers generally have a relatively low melt flow rate combined with high melt strength and high melt ductility.

[0089] The high melt strength propylene homopolymer (B) preferably has an F greater than 20.0 cN. 30 Melt strength and v greater than 200mm / s 30 Melt ductility, preferably with an F greater than 20.0 to 50.0 cN 30 Melt strength and v greater than 200 to 300 mm / s 30 Melt ductility. 30 Melt strength and v 30 Melt ductility was measured according to ISO 16790:2005.

[0090] The high melt strength propylene homopolymer (B) preferably has specific properties, like specific melt properties.

[0091] The high melt strength propylene homopolymer (B) preferably has a melt strength F of 20.0 to 50.0 cN, preferably in the range of 25.0 to 45.0 cN, more preferably in the range of 30.0 to 40.0 cN, such as in the range of 32.0 to 38.0 cN. 30 (ISO16790:2005).

[0092] The high melt strength propylene homopolymer (B) preferably has a melt ductility v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s and more preferably in the range of 230 to 280 mm / s, such as in the range of 240 to 280 mm / s. 30 (ISO 16790:2005).

[0093] The high melt strength propylene homopolymer (B) has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230°C) in the range of 0.5 to 5.0 g / 10 min, preferably in the range of 1.0 to 3.0 g / 10 min and more preferably in the range of 1.2 to 2.5 g / 10 min, like in the range of 1.4 to 2.3 g / 10 min.

[0094] According to a preferred embodiment, the high melt strength propylene homopolymer (B) has two or more of the following properties, and preferably has all of the following properties:

[0095] i) a melt strength F in the range of 20.0 to 50.0 cN, preferably in the range of 25.0 to 45.0 cN and more preferably in the range of 30.0 to 40.0 cN, such as in the range of 32.0 to 38.0 cN 30 (ISO 16790:2005),

[0096] ii) a melt ductility v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s and more preferably in the range of 230 to 280 mm / s, such as in the range of 240 to 280 mm / s 30 (ISO 16790:2005),

[0097] iii) a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230°C) in the range of 0.5 to 5.0 g / 10 min, preferably in the range of 1.0 to 3.0 g / 10 min and more preferably in the range of 1.2 to 2.5 g / 10 min, such as in the range of 1.4 to 2.3 g / 10 min.

[0098] The high melt strength propylene homopolymer (B) may have a melting point of at least 130°C, more preferably at least 135°C and most preferably at least 140°C. The crystallization temperature may be at least 110°C, more preferably at least 120°C.

[0099] The high melt strength propylene homopolymer (B) may contain unsaturated units different from propylene, such as (one or more) difunctional unsaturated monomers and / or (one or more) multifunctional unsaturated low molecular weight polymers as defined in detail below. Therefore, in the case of the high melt strength propylene homopolymer (B), the definition of homopolymer actually refers to the unmodified propylene homopolymer used to obtain the high melt strength propylene homopolymer (B) by chemical modification as defined in detail below, which unmodified propylene homopolymer is preferably a linear polypropylene.

[0100] Thus, in a preferred embodiment the high melt strength propylene homopolymer (B) comprises units derived from

[0101] (i) propylene, and

[0102] (ii) (one or more) difunctional unsaturated monomers and / or (one or more) polyfunctional unsaturated low molecular weight polymers.

[0103] As used above, "difunctionally unsaturated" or "polyfunctionally unsaturated" preferably means the presence of two or more non-aromatic double bonds, such as are present in, for example, divinylbenzene or cyclopentadiene or polybutadiene. Only such difunctionally unsaturated compounds or polyfunctionally unsaturated compounds are used which can be polymerized, preferably by means of free radicals (see below). The unsaturated sites in the difunctionally unsaturated compounds or polyfunctionally unsaturated compounds are in their chemically bound state and are not actually "unsaturated" since the double bonds are each used for covalent bonding to the polymer chain of the unmodified propylene homopolymer, preferably a linear propylene homopolymer.

[0104] The reaction of (one or more) difunctional unsaturated monomers and / or (one or more) multifunctional unsaturated low molecular weight polymers (which preferably have a number average molecular weight (Mn) of ≤10000 g / mol, synthesized from one and / or more unsaturated monomers and an unmodified propylene homopolymer (preferably a linear propylene homopolymer)) is carried out in the presence of a thermal free radical former (e.g. a decomposing free radical former, such as a thermally decomposable peroxide).

[0105] The difunctional unsaturated monomer can be

[0106] - divinyl compounds such as divinylaniline, m-divinylbenzene, p-divinylbenzene, divinylpentane and divinylpropane;

[0107] - allyl compounds such as allyl acrylate, allyl methacrylate, allyl methylmaleate and allyl vinyl ether;

[0108] - dienes, such as 1,3-butadiene, chloroprene, cyclohexadiene, cyclopentadiene, 2,3-dimethylbutadiene, heptadiene, hexadiene, isoprene and 1,4-pentadiene;

[0109] - Aromatic and / or aliphatic bis(maleimide)bis(citraconimide)s and mixtures of these unsaturated monomers.

[0110] Particularly preferred difunctional unsaturated monomers are 1,3-butadiene, isoprene, dimethylbutadiene and divinylbenzene.

[0111] The multifunctional unsaturated low molecular weight polymer, preferably having a number average molecular weight (Mn) of ≤ 10000 g / mol, can be synthesized from one or more unsaturated monomers.

[0112] Examples of such low molecular weight polymers are

[0113] - polybutadiene, particularly where the different microstructures in the polymer chain (i.e., 1,4-cis, 1,4-trans and 1,2-(vinyl)) are predominantly 1,2-(vinyl)

[0114] - Copolymers of butadiene and styrene having 1,2-(vinyl) groups in the polymer chain.

[0115] Preferred low molecular weight polymers are polybutadienes, especially polybutadienes having greater than 50.0% by weight of butadiene in the 1,2-(vinyl) configuration.

[0116] The high melt strength propylene homopolymer (B) may contain more than one difunctional unsaturated monomer and / or multifunctional unsaturated low molecular weight polymer. Even more preferably, the total amount of (one or more) difunctional unsaturated monomers and (one or more) multifunctional unsaturated low molecular weight polymers in the high melt strength propylene homopolymer (B) is 0.01 to 10.0 wt.-%, based on the total weight of the high melt strength propylene homopolymer (B).

[0117] In a preferred embodiment the high melt strength propylene homopolymer (B) contains no additives. Hence, if the inventive polypropylene composition comprises additives (A) these additives are not introduced into the polypropylene composition during the production of the high melt strength propylene homopolymer (B).

[0118] The high melt strength propylene homopolymer (B) further preferably has a low gel content, typically below 1.00 wt%. Preferably the gel content is less than 0.80 wt%, more preferably less than 0.50 wt%.

[0119] A suitable high melt strength propylene homopolymer (B) is WB140HMS TM Commercially available from Borealis AG.

[0120] Copolymer of ethylene (C)

[0121] The polypropylene composition may further comprise a copolymer of ethylene (C) in an amount of 0 to 20.0 wt.-%, preferably 0 to 15.0 wt.-%, more preferably 0 to 12.5 wt.-%, based on the total weight of the composition.

[0122] In one embodiment the polypropylene composition does not comprise a copolymer of ethylene (C).In said embodiment the polymer components of the polypropylene composition comprise, preferably consist of, components (A) and (B), but do not comprise a copolymer of ethylene (C).

[0123] In another embodiment, the polypropylene composition comprises a copolymer of ethylene (C). In said embodiment, the copolymer of ethylene is present in the polypropylene composition in an amount of 2.5 to 20.0 wt.-%, preferably 5.0 to 15.0 wt.-%, more preferably 7.5 to 12.5 wt.-%, based on the total weight of the composition. In said embodiment, the polymer component of the polypropylene composition comprises, preferably consists of, components (A), (B) and (C).

[0124] The copolymer of ethylene (C) has a molecular weight of 860 to 880 kg / m 3 In the range of 862 to 877 kg / m 3 In the range of 865 to 875 kg / m 3 Density within the range.

[0125] The copolymer of ethylene (C) has a melt flow rate MFR2 of 0.1 to 2.5 g / 10 min, preferably 0.2 to 2.0 g / 10 min, more preferably 0.5 to 1.5 g / 10 min.

[0126] The copolymer of ethylene (C) comprises at least one, preferably one comonomer selected from α-olefins having 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms. Preferably, at least one comonomer, preferably a comonomer selected from 1-hexene or 1-octene, most preferably 1-octene.

[0127] It is particularly preferred that the copolymer (C) of ethylene contains 1-octene as single comonomer(s).

[0128] The copolymer of ethylene (C) preferably has a melting temperature Tm of 40 to 70°C, preferably 45 to 65°C, more preferably 50 to 60°C.

[0129] The copolymer of ethylene (C) is preferably an ethylene-based plastomer.

[0130] The copolymer of ethylene (C) may be polymerized via methods well known in the art, such as a solution polymerization process preferably in the presence of a single-site catalyst, or alternatively may be a commercially available polyethylene grade. It will be appreciated that commercially available grades may contain common additives.

[0131] Injection molding products

[0132] In another aspect, the present invention relates to an injection molded article comprising the polypropylene composition as described above or below.

[0133] Thus, preferably all aspects of the polypropylene composition and its components as described above or below are suitable for injection moulded articles.

[0134] The injection molded article is preferably an automotive article or a packaging article.

[0135] The injection molded article preferably comprises the polypropylene composition in an amount of 90 to 100 wt%, more preferably 95 to 100 wt%, based on the total weight of the injection molded article.

[0136] The injection molded article may contain additional components, such as additional polymer components, fillers or additives, in an amount of 0 to 10 wt %, more preferably 0 to 5 wt %, based on the total weight of the injection molded article.

[0137] The injection molded article preferably has a pressure of 890 to 1100 kg / m 3 density.

[0138] Hence, the density depends on the presence of inorganic fillers in the polypropylene composition.

[0139] If no inorganic filler is present in the polypropylene composition, the injection molded article preferably has a carbon content of 890 to 915 kg / m 3 , more preferably 895 to 910 kg / m 3 density.

[0140] When inorganic fillers are present in the polypropylene composition, the injection molded articles may have a weight up to 1100 kg / m 3 density.

[0141] As can be seen from the density, the injection-moulded article is preferably not foamed but a solid injection-moulded article.

[0142] The injection molded article preferably shows a good balance of properties in terms of stiffness and toughness. This can preferably be seen in the following properties:

[0143] The injection molded article preferably has a flexural modulus of 1200 to 2000 MPa, more preferably 1300 to 1850 MPa, still more preferably 1400 to 1750 MPa.

[0144] Furthermore, the injection molded article preferably has a maximum force at 23° C. of 1750 to 2750 N, more preferably 2000 to 2600 N, still more preferably 2100 to 2500 N.

[0145] Furthermore, the injection molded article preferably has an energy to maximum force at 23° C. of 10 to 20 J, more preferably 12 to 18 J, still more preferably 13 to 17 J.

[0146] Further, the injection molded article preferably has a puncture energy at 23° C. of 15 to 35 J, more preferably 18 to 32 J, still more preferably 20 to 30 J.

[0147] Still further, the injection molded article preferably has a tensile modulus of 1200 to 2000 MPa, more preferably 1300 to 1850 MPa, still more preferably 1400 to 1800 MPa.

[0148] Furthermore, the injection molded article preferably has a tensile strain at break of 10% to 75%, more preferably 12% to 70%, still more preferably 15% to 60%.

[0149] Furthermore, the injection molded article preferably has a tensile strain at tensile strength of 2.0% to 7.5%, more preferably 2.5% to 7.0%, still more preferably 3.0% to 6.5%.

[0150] Further, the injection molded article preferably has a tensile strain at yield of 2.0% to 7.5%, more preferably 2.5% to 7.0%, still more preferably 3.0% to 6.5%.

[0151] Still further, the injection molded article preferably has a tensile strength of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa.

[0152] Furthermore, the injection molded article preferably has a tensile stress at break of 10 to 35 MPa, more preferably 13 to 30 MPa, still more preferably 15 to 25 MPa.

[0153] Further, the injection molded article preferably has a yield tensile stress of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa.

[0154] Foam products

[0155] In a further aspect the present invention relates to a foamed article comprising the polypropylene composition as described above or below.

[0156] Thus, preferably, all aspects of the polypropylene composition and its components as described above or below are suitable for use in foamed articles.

[0157] The foamed article is preferably a foamed injection molded article, more preferably an automotive article or a packaging article.

[0158] The foamed injection-molded article is preferably produced by core back injection molding as described above.

[0159] The foamed article preferably comprises the polypropylene composition in an amount of 90.0 to 99.9 wt%, more preferably 95.0 to 99.5 wt%, based on the total weight of the injection molded article.

[0160] The foamed article is preferably produced by foaming the polypropylene composition in the presence of a blowing agent.

[0161] The term "blowing agent" refers to an agent capable of generating a cellular structure in the polypropylene composition during foaming.

[0162] The blowing agent may be a physical blowing agent, typically a gas such as carbon dioxide, nitrogen or other inert gas.

[0163] However, it is preferred that the blowing agent is a chemical blowing agent.

[0164] Therefore, the polypropylene composition is preferably blended, more preferably melt blended, with a blowing agent, preferably a chemical blowing agent.

[0165] The melt of the polypropylene composition and the blowing agent is preferably formed into the form of an article, preferably by injection moulding.

[0166] When formed into the form of an article, the chemical foaming agent is preferably activated. Upon activation, the chemical foaming agent releases a gas (such as nitrogen or carbon dioxide) which forms bubbles in the melt of the article.

[0167] When the bubbles solidify, they solidify into cells in the product, thereby forming a foamed product.

[0168] When the core back injection molding technique is used to produce the foamed article, the chemical foaming agent is activated by opening the mold to a predetermined extent, such as 1 mm to 5 mm, preferably 2 mm to 3 mm.

[0169] The chemical blowing agent is preferably introduced into the polypropylene composition in an amount of 0.1 to 10.0 wt.-%, more preferably 0.2 to 5.0 wt.-%, based on the combined weight of the polypropylene composition and the chemical blowing agent.

[0170] The chemical blowing agent is preferably an endothermic chemical blowing agent.

[0171] Preferably, the chemical blowing agent is an organic chemical blowing agent, such as a polycarboxylic acid, for example citric acid, fumaric acid, tartaric acid, sodium hydrogen citrate, monosodium citrate or a combination thereof.

[0172] The chemical blowing agent may also be an inorganic chemical blowing agent, such as a carbonate, for example ammonium carbonate or a divalent bicarbonate, for example sodium bicarbonate or zinc bicarbonate.

[0173] The chemical blowing agent may also be a mixture of an organic chemical blowing agent and an inorganic chemical blowing agent, such as a mixture of a polycarboxylic acid and a divalent bicarbonate (eg sodium bicarbonate or zinc bicarbonate).

[0174] The chemical blowing agent preferably releases carbon dioxide in gaseous form which forms bubbles in the melt.

[0175] Preferably, upon release of gas (preferably carbon dioxide), the residual reaction products of the chemical blowing agent form solid crystals which can act as nucleating agents for the solidifying melt.

[0176] The chemical blowing agent is preferably added to the polypropylene composition in the form of a masterbatch, wherein the active ingredient of the chemical blowing agent is distributed in a polymer matrix.Preferably, the polymer matrix is ​​a vinyl polymer, such as low density polyethylene.

[0177] The active ingredient of the chemical blowing agent is preferably present in the masterbatch in an amount of 5 to 35 wt %, more preferably 10 to 30 wt %, still more preferably 15 to 25 wt %, based on the total amount of the masterbatch.

[0178] When the chemical blowing agent is added as a masterbatch, the amount of polymer matrix is ​​calculated based on the amount of chemical blowing agent rather than the amount of the polypropylene composition.

[0179] Chemical blowing agents are preferably activated at relatively high temperatures of 200 to 250°C, more preferably 210 to 230°C.

[0180] Suitable chemical blowing agents are commercially available, such as Panthelene H65C, Panthelene H25C (both available from EIWA CHEMICAL IND. CO., LTD), or Maxithen HP 788810 / 20TR (available from Gabriel-Chemie GmbH).

[0181] The foamed article preferably has an average cell size in the longitudinal direction of 100 to 200 μm, more preferably 120 to 175 μm, still more preferably 130 to 160 μm.

[0182] Further, the foamed article preferably has an average cell size in the transverse direction of 110 to 225 μm, more preferably 135 to 210 μm, still more preferably 150 to 200 μm.

[0183] The foamed article preferably exhibits an improved balance of properties of low density, high toughness and high stiffness. This can preferably be seen in the following properties:

[0184] The foamed article preferably has a density of 350 to 650 kg / m 3 , preferably 375 to 625 kg / m 3 , more preferably 400 to 600 kg / m 3 density.

[0185] The foamed article further preferably has a flexural modulus of 600 to 1200 MPa, preferably 650 to 1100 MPa, more preferably 675 to 1050 MPa.

[0186] Furthermore, the foamed article preferably has a maximum force at 23° C. of 400 to 1750 N, more preferably 550 to 1600 N, still more preferably 700 to 1500 N.

[0187] Furthermore, the foamed article preferably has an energy to maximum force at 23° C. of 1.8 to 10.0 J, preferably 2.0 to 9.0 J.

[0188] Further, the foamed article preferably has a puncture energy at 23°C of 2.0 to 10.0 J, more preferably 2.3 to 9.0 J.

[0189] Still further, the foamed article preferably has a tensile modulus of 350 to 800 mPa, preferably 375 to 775 MPa, more preferably 400 to 750 MPa.

[0190] Furthermore, the foamed article preferably has a tensile strain at break of 20% to 100%, more preferably 25% to 85%, still more preferably 32% to 70%.

[0191] Furthermore, the foamed article preferably has a tensile strain under tensile strength of 2.0% to 7.5%, more preferably 2.5% to 7.0%, still more preferably 3.0% to 6.5%.

[0192] Further, the foamed article preferably has a tensile strain at yield of 2.5% to 30.0%, more preferably 5.0% to 25.0%, still more preferably 7.5% to 20.0%.

[0193] Still further, the foamed article preferably has a tensile strength of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa.

[0194] Furthermore, the foamed article preferably has a tensile stress at break of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa.

[0195] Further, the foamed article preferably has a yield tensile stress of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa.

[0196] The density of the foamed article (ie the density reduction of the foamed article) is preferably 35 to 65%, more preferably 40 to 55% of the density of the unfoamed injection moulded article of the same polypropylene composition (corresponding to 100%).

[0197] Further, the flexural modulus of the foamed article is preferably 500 to 1500 MPa, more preferably 700 to 1200 MPa lower than the flexural modulus of an unfoamed injection molded article of the same polypropylene composition.

[0198] Still further, the puncture energy of the foamed article is preferably 10 to 30 J, more preferably 15 to 25 J lower than the flexural modulus of the unfoamed injection molded article of the same polypropylene composition.

[0199] use

[0200] In another aspect, the present invention relates to the use of a polypropylene composition as described above or below and a chemical blowing agent for producing a foamed article, preferably a foamed injection moulded article.

[0201] Therefore, preferably, all aspects of the polypropylene composition and its components and foamed articles as described above or below are suitable for this use.

[0202] Further non-limiting embodiments and aspects of the present invention are defined in the following items [1] to

[15] :

[0203] [1] A polypropylene composition comprising

[0204] (A) 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-%, based on the total weight of the composition, of a heterophasic propylene copolymer comprising a matrix phase and an elastomeric phase dispersed in said matrix phase and having a xylene cold soluble (XCS) fraction in an amount of 10.0 to 25.0 wt.-%, preferably 11.5 to 22.5 wt.-%, more preferably 12.5 to 20.0 wt.-%, based on the total amount of heterophasic propylene copolymer (A);

[0205] (B) 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-%, based on the total weight of the composition, of a high melt strength propylene homopolymer having a melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg, of 0.5 to 5.0 g / 10 min, preferably 1.0 to 3.0 g / 10 min and more preferably 1.2 to 2.5 g / 10 min;

[0206] (C) 0 to 20.0 wt. %, preferably 0 to 15.0 wt. %, more preferably 0 to 12.5 wt. % of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, based on the total weight of the composition, the copolymer having a molecular weight of 860 to 880 kg / m 3 , preferably 862 to 877 kg / m 3 , more preferably 865 to 875 kg / m 3 A density determined according to ISO 1183 of 0.1 to 2.5 g / 10 min, preferably 0.2 to 2.0 g / 10 min, more preferably 0.5 to 1.5 g / 10 min, determined according to ISO 1133 at a temperature of 190° C. and a load of 2.16 kg.

[0207] [2] The polypropylene composition according to item [1], wherein the composition has

[0208] 890 to 1100 kg / m 3 density determined in accordance with ISO 1183; and / or

[0209] • A melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg, of 10.0 to 55.0 g / 10 min, preferably 15.0 to 50.0 g / 10 min, more preferably 17.0 to 45.0 g / 10 min.

[0210] [3] The polypropylene composition according to item [1] or [2], wherein the composition has one or more of the following properties, or has all of the following properties:

[0211] a tensile modulus measured according to ISO 527-1 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1800 MPa; and / or

[0212] 10 to 75%, more preferably 12 to 70%, still more preferably 15 to 60% of the tensile strain at break measured according to ISO 527-1; and / or

[0213] a tensile strength measured according to ISO 527-1 of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa; and / or

[0214] ● a tensile stress at break measured according to ISO 527-1 of 10 to 35 MPa, more preferably 13 to 30 MPa, still more preferably 15 to 25 MPa; and / or

[0215] a flexural modulus measured according to ISO 178 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1750 MPa; and / or

[0216] a puncture energy measured at 23°C according to ISO 6603-2 of 15 to 35 J, more preferably 18 to 32 J, still more preferably 20 to 30 J; and / or

[0217] 1750 to 2750 N, more preferably 2000 to 2600 N, still more preferably 2100 to 2500 N according to ISO

[0218] 6603-2 Maximum force at 23°C measured at 23°C; and / or

[0219] • Energy to Maximum Force at 23°C measured according to ISO 6603-2 at 23°C of 10 to 20 J, more preferably 12 to 18 J, still more preferably 13 to 17 J.

[0220] [4] The polypropylene composition according to any of items [1] to [3], wherein the heterophasic propylene copolymer (A) has one or more of the following properties, or has all of the following properties:

[0221] In the range of 15.0 to 100.0 g / 10 min, more preferably in the range of 20.0 to 90.0 g / 10 min, still more preferably in the range of 25.0 to 85.0 g / 10 min, most preferably in the range of 30.0 to 80.0 g / 10 min according to ISO

[0222] 1133-1 Melt flow rate MFR2 measured at 230°C under a load of 2.16 kg; and / or

[0223] xylene cold soluble fraction (XCS), determined according to ISO 16152 at 25 °C, present in an amount in the range of 8.0 to 25.0 wt.-%, more preferably in the range of 10.0 to 22.5 wt.-%, still more preferably in the range of 1 1.0 to 21.0 wt.-%, most preferably in the range of 12.5 to 20.0 wt.-%, based on the total weight of the heterophasic propylene copolymer (A); and / or

[0224] an intrinsic viscosity of the xylene cold soluble fraction (IV(XCS)) determined in decalin according to DIN ISO 1628 / 1 in the range of 2.00 to 4.00 dl / g, more preferably in the range of 2.30 to 3.70 dl / g, still more preferably in the range of 2.50 to 3.40 dl / g, most preferably in the range of 2.70 to 3.30 dl / g; and / or

[0225] · In the range of 20.0 to 60.0 wt. %, more preferably in the range of 25.0 to 50.0 wt. %, still more preferably in the range of 30.0 to 45.0 wt. %, most preferably in the range of 32.5 to 40.0 wt. % by quantitative 13 C{ 1 H} NMR measurement of the ethylene content of the xylene cold soluble fraction (C2(XCS)); and / or

[0226] · in the range of 3.0 to 15.0 wt. %, more preferably in the range of 4.0 to 12.0 wt. %, still more preferably in the range of 5.0 to 10.0 wt. %, most preferably in the range of 6.0 to 8.5 wt. % by quantitative 13 C{ 1 H}

[0227] NMR measurement was performed to measure the total ethylene content (C2).

[0228] [5] A polypropylene composition according to any of items [1] to [4], wherein the heterophasic propylene copolymer (A) comprises, preferably consists of, two heterophasic propylene copolymers (A-1) and (A-2), wherein the heterophasic propylene copolymer (A-1) has a lower melt flow rate MFR2 than the heterophasic propylene copolymer (A-2), and the weight ratio of the heterophasic propylene copolymer (A-1) to the heterophasic propylene copolymer (A-2) in the polypropylene composition is in the range of 40:60 to 60:40, preferably in the range of 45:55 to 55:45.

[0229] [6] The polypropylene composition according to any one of items [1] to [5], wherein the high melt strength propylene homopolymer (B) is branched, and the branches are introduced into the polymer chain of the high melt strength propylene homopolymer (B) as side chains by polymerization in the presence of a single active site catalyst or by chemical modification.

[0230] [7] The polypropylene composition according to any one of items [1] to [6], wherein the high melt strength propylene homopolymer (B) has a melt strength F in the range of 20.0 to 50.0 cN, preferably in the range of 25.0 to 45.0 cN and more preferably in the range of 30.0 to 40.0 cN, such as in the range of 32.0 to 38.0 cN. 30 (ISO 16790:2005); and / or a melt ductility v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s and more preferably in the range of 230 to 280 mm / s, such as in the range of 240 to 280 mm / s 30 (ISO 16790:2005).

[0231] [8] The polypropylene composition according to any one of items [1] to [7], wherein the ethylene copolymer (C) is a copolymer of ethylene and 1-octene comonomer units.

[0232] [9] An injection molded article comprising the polypropylene composition according to any one of items [1] to [8].

[0233]

[10] The injection molded article according to item [9], wherein the article has one or more of the following properties, or has all of the following properties:

[0234] a tensile modulus measured according to ISO 527-1 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1800 MPa; and / or

[0235] ● a tensile strain at break measured according to ISO 527-1 of 10 to 75%, more preferably 12 to 70%, still more preferably 15 to 60%; and / or

[0236] ● a tensile strength measured according to ISO 527-1 of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa; and / or

[0237] ● a tensile stress at break measured according to ISO 527-1 of 10 to 35 MPa, more preferably 13 to 30 MPa, still more preferably 15 to 25 MPa; and / or

[0238] a flexural modulus measured according to ISO 178 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1750 MPa; and / or

[0239] a puncture energy measured at 23°C according to ISO 6603-2 of 15 to 35 J, more preferably 18 to 32 J, still more preferably 20 to 30 J; and / or

[0240] ● 1750 to 2750 N, more preferably 2000 to 2600 N, still more preferably 2100 to 2500 N according to ISO

[0241] 6603-2 Maximum force at 23°C measured at 23°C; and / or

[0242] • Energy to Maximum Force at 23°C measured according to ISO 6603-2 at 23°C of 10 to 20 J, more preferably 12 to 18 J, still more preferably 13 to 17 J.

[0243]

[11] A foamed article, preferably a foamed injection molded article, comprising the polypropylene composition according to any one of items [1] to [8].

[0244]

[12] The foamed article according to item

[11] , wherein the polypropylene composition is foamed in the presence of a foaming agent, preferably a chemical foaming agent.

[0245]

[13] The foamed article according to item

[11] or

[12] , wherein the article has one or more of the following properties, or has all of the following properties:

[0246] 350 to 650 kg / m 3 , preferably 375 to 625 kg / m 3 , more preferably 400 to 600 kg / m 3 According to ISO

[0247] 1183Measured density;

[0248] 600 to 1200 MPa, preferably 650 to 1100 MPa, more preferably 675 to 1050 MPa according to ISO

[0249] 178 measured flexural modulus;

[0250] A tensile modulus measured according to ISO 527 of 350 to 800 mPa, preferably 375 to 775 MPa, more preferably 400 to 750 MPa;

[0251] A tensile strain at break of 20 to 100%, more preferably 25 to 85%, still more preferably 32 to 70%;

[0252] A tensile strain at tensile strength measured according to ISO 527 of 2.0 to 7.5%, more preferably 2.5 to 7.0%, still more preferably 3.0 to 6.5%;

[0253] 2.5 to 30.0%, more preferably 5.0 to 25.0%, still more preferably 7.5 to 20.0% tensile strain at yield measured according to ISO 527;

[0254] ● 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa according to ISO

[0255] 527 measured tensile strength;

[0256] ● 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa according to ISO

[0257] 527 measured tensile stress at break;

[0258] 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa according to ISO

[0259] 527 measured tensile stress at yield;

[0260] Energy to maximum force measured at 23°C according to ISO 6603-2 of 1.8 to 10.0 J, preferably 2.0 to 9.0 J; and / or

[0261] • A puncture energy measured at 23° C. according to ISO 6603-2 of 2.0 to 10.0 J, preferably 2.3 to 9.0 J.

[0262]

[14] The foamed article according to any one of items

[11] to

[13] , wherein the flexural modulus measured according to ISO 178 is 500 to 1500 MPa lower than the flexural modulus of the unfoamed injection molded article measured according to ISO 178.

[0263]

[15] Use of the polypropylene composition according to any one of items [1] to [8] and a chemical foaming agent for producing a foamed article, preferably a foamed injection molded article.

[0264] The present invention is further illustrated by the following examples.

[0265] Examples

[0266] 1. Measurement method

[0267] Melt flow rate

[0268] The melt flow rate (MFR) is determined according to ISO 1133-1 and is expressed in g / 10 min. The MFR indicates the fluidity of a polymer and therefore its processability. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polypropylene is determined at a temperature of 230°C and a load of 2.16 kg. The MFR2 of polyethylene is determined at a temperature of 190°C and a load of 2.16 kg.

[0269] Differential Scanning Calorimetry (DSC)

[0270] Differential scanning calorimetry (DSC) analysis, melting temperature (T m ) and melting enthalpy (H m ), crystallization temperature (T c ) and heat of crystallization (H c , H CR ) 5 to 7 mg samples were measured using a TA Instrument Q200 differential scanning calorimeter (DSC). DSC was run according to ISO 11357 / Part 3 / Method C2 with a heating / cooling / heating cycle in the temperature range of -30 to +225°C at a scanning rate of 10°C / min. The crystallization temperature (T c ) and heat of crystallization (H c ) is determined by the cooling step, while the melting temperature (T m ) and melting enthalpy (H m ) is determined by the second heating step.

[0271] Xylene Cold Solubles (XCS)

[0272] The xylene cold soluble fraction at room temperature (XCS, wt. %) is determined according to ISO 16152; 5th edition; 2005-07-01 at 25°C.

[0273] Tensile properties

[0274] Tensile properties were determined according to ISO 527-2 (crosshead speed = 1 mm / min; test speed 50 mm / min, at 23°C) on 1B specimens.

[0275] Crystex analysis

[0276] Crystallization and soluble fraction method

[0277] The crystalline fraction (CF) and the soluble fraction (SF) of the polypropylene (PP) composition as well as the comonomer content and the intrinsic viscosity of each fraction were analyzed by CRYSTEX QC, Polymer Char (Valencia, Spain).

[0278] Figure 1a shows a schematic diagram of the CRYSTEX QC instrument. As shown in Figure 1b, the crystalline fraction and the amorphous fraction are separated by a temperature cycle of dissolving in 1,2,4-trichlorobenzene (1,2,4-TCB) at 160°C, crystallizing at 40°C, and re-dissolving in 1,2,4-TCB at 160°C. The quantification of SF and CF and the determination of ethylene content (C2) are achieved with the aid of an infrared detector (IR4), and the intrinsic viscosity (iV) is determined using an online 2-capillary viscometer.

[0279] The IR4 detector is based on two different wavelengths (CH3 stretching vibration (centered at about 2960 cm -1 ) and CH X Extension vibration (2700 to 3000cm -1 The IR4 detector is calibrated with a series of 8 EP copolymers with known ethylene contents ranging from 2 wt% to 69 wt% (measured by 13 C-NMR spectroscopy), and each EP copolymer used for calibration had multiple concentrations in the range of 2 and 13 mg / ml. In order to simultaneously experience two characteristics of various concentrations of polymers during Crystex analysis, concentration and ethylene content, the following calibration equation was applied:

[0280] Concentration = a + b * absorbance (CH) + c * (absorbance (CH) x ))2+d*absorbance(CH3)+e*(absorbance(CH3) 2 +f*Absorbance(CH x )*Absorbance(CH3) (Equation 1)

[0281] CH3 / 1000C=a+b*absorbance(CH x )+c*absorbance(CH3)+d*(absorbance(CH3) / absorbance(CH x ))+e*(absorbance(CH3) / absorbance(CH x )) 2 (Equation 2)

[0282] Constants a to e of Equation 1 and constants a to f of Equation 2 are determined by using least squares regression analysis.

[0283] The following relationship is used to convert CH3 / 1000C to ethylene content in wt %:

[0284] Weight % (ethylene in EP copolymer) = 100 - CH3 / 1000TC*0.3 (Equation 3)

[0285] The amounts of the soluble fraction (SF) and the crystalline fraction (CF) are related by means of the XS calibration to the amount of "xylene cold solubles" (XCS) and the xylene cold insolubles (XCI) fraction, respectively, determined according to the standard gravimetric method according to ISO 16152. The XS calibration was achieved by testing various EP copolymers with XS contents in the range of 2 to 31 wt.%. The determined XS calibration is linear:

[0286] Weight %XS=1.01*weight %SF (Equation 4)

[0287] The intrinsic viscosity (IV) of the parent EP copolymer and its soluble fraction and crystalline fraction was determined using an online 2-capillary viscometer and related to the corresponding IV determined by the standard method in decalin according to ISO 1628-3. Calibration was achieved using various EP PP copolymers with IV = 2 to 4 dL / g. The determined calibration curve was linear:

[0288] IV(dL / g)=a*Vsp / c (Equation 5)

[0289] Weigh out the sample of the PP composition to be analyzed at a concentration of 10 mg / ml to 20 mg / ml. After automatically filling the vial with 1,2,4-TCB containing 250 mg / 1 of 2,6-tert-butyl-4-methylphenol (BHT) as an antioxidant, dissolve the sample at 160°C until complete dissolution is achieved, usually for 60 min, and continue stirring at 400 rpm. To avoid sample degradation, cover the polymer solution with a N2 atmosphere during dissolution.

[0290] As shown in Figures 1a and 1b, a defined volume of sample solution is injected into a column filled with an inert carrier, where crystallization of the sample and separation of the soluble fraction from the crystalline portion are performed. This process is repeated twice. During the first injection, the entire sample is measured at high temperature, and IV [dl / g] and C2 [wt%] of the PP composition are determined. During the second injection, the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) (wt% SF, wt% C2, IV) are measured using the crystallization cycle.

[0291] based on 13 Determination of C2 Content of Calibration Standards by C NMR Spectroscopy

[0292] Use for 1 H and 13 Quantitative measurements were recorded in solution on a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz, respectively. 13 C{ 1 H} NMR spectroscopy. Nitrogen was used for all pneumatics and all spectra were 13 C optimized 10mm extended temperature probe was recorded at 125°C. Approximately 200mg of material was dissolved in 3ml of 1,2-tetrachloroethane-d2 (TCE-d2) along with chromium (III) acetylacetonate (Cr(acac)3) to give a 65mM solution of the relaxation agent in the solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure a homogeneous solution, the NMR tube was further heated in a rotary oven for at least 1 hour after initial sample preparation in a heating block. After insertion into the magnet, the tube was rotated at 10Hz. This setup was selected primarily for high resolution and quantitatively required for accurate ethylene content quantification. Standard single pulse excitation without NOE was used, with optimized tip angle, 1s recycle delay and double-stage WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225, Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transient values ​​were collected for each spectrum. For quantitative 13 C{ 1H} NMR spectra are processed, integrated and the relevant quantitative properties are determined from the integrals. All chemical shifts are indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This method allows for comparable references even if the structural unit does not exist. Characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, HN, Macromolecules 17 (1984), 1950), and the comonomer fraction was calculated as the fraction of ethylene in the polymer relative to all monomers in the polymer: fE = (E / (P+E)). Using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157), by 13 C{ 1 The comonomer fraction is quantified by integrating multiple signals over the entire spectral area in the {H} spectrum. This method was chosen because of its robustness and ability to account for the presence of regional defects when necessary. The integration region was slightly adjusted to improve applicability over the entire range of comonomer contents encountered. For systems with very low ethylene content where only isolated ethylene in the PPEPP sequence was observed, the method of Wang et al. was modified to reduce the impact of the integration of sites that are no longer present. This approach reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine the absolute ethylene content to the following: E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ)). By using this set of sites, the corresponding integration equation becomes: E=0.5(I H +I G +0.5(I C +I D )), using the same symbols used in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157). The equation for absolute propylene content was not modified. The mole percentage of comonomer incorporation was calculated from the mole fraction: E [mole %] = 100 * fE. The weight percentage of comonomer incorporation was calculated from the mole fraction: E [weight %] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1-fE) * 42.08)).

[0293] By quantitative 13 C{ 1 Quantification of comonomer content of poly(propylene-co-ethylene) copolymers by H}NMR

[0294] Use for 1 H and 13Quantitative measurements were recorded in solution on a Bruker Avance NEO 400 NMR spectrometer operating at 400.15 and 100.62 MHz, respectively. 13 C{ 1 H} NMR spectroscopy. Nitrogen was used for all pneumatics and all spectra were 13 C optimized 10 mm extended temperature probe was recorded at 125 °C. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) together with chromium (III) acetylacetonate (Cr(acac)3) and approximately 3 mg of BHT (2,6-di-tert-butyl-4-methylphenol, CAS128-37-0) to obtain a 60 mM solution of the relaxation agent in the solvent {8}. To ensure a homogeneous solution, the NMR tube was further heated in a rotary oven for at least 1 hour after initial sample preparation in a heating block. After insertion into the magnet, the tube was rotated at 10 Hz. This setup was chosen primarily for high resolution and is quantitatively required for accurate ethylene content quantification. Standard single pulse excitation without NOE was employed, using an optimized top cone angle, 1 s recycle delay and a two-stage WALTZ16 decoupling scheme {3, 4}. A total of 6144 (6k) transients were collected for each spectrum. Quantification was performed using a dedicated computer program 13 C{ 1 The H} NMR spectra were processed, integrated and the relevant quantitative properties were determined from the integration. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allows for comparable references even if this structural unit is not present. Characteristic signals corresponding to the incorporation of ethylene were observed {7}.

[0295] Using the method of Wang et al. {6}, we 13 C{ 1 The comonomer fraction is quantified by integrating multiple signals over the entire spectral area in the H} spectrum. This approach was chosen for its robustness and ability to account for the presence of regio defects when required. The integration area was slightly adjusted to improve applicability over the entire range of comonomer content encountered.

[0296] For systems where only isolated ethylene in the PPEPP sequence is observed, the method of Wang et al. was modified to reduce the effect of non-zero integrals at sites known to be absent. This approach reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine absolute ethylene content to:

[0297] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0298] Using this set of sites, the corresponding integral equation becomes:

[0299] E = 0.5 (IH + IG + 0.5 (IC + ID))

[0300] The same symbols used in the article by Wang et al. {6} were used. No modifications were made to the equations for absolute propylene content.

[0301] Calculate the mole percentage of comonomer incorporation from the mole fraction:

[0302] E[mol%]=100*fE

[0303] Calculate the weight percent of comonomer incorporation from the mole fraction:

[0304] E[weight%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0305] bibliography:

[0306] 1) Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443.

[0307] 2) Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromolecules 30 (1997) 6251.

[0308] 3) Zhou, Z., Kuemmerle, R., Qiu,

[0309] 4) Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128.

[0310] 5)Resconi,L.,Cavallo,L.,Fait,A.,Pimontesi,F.,Chem.Rev.2000,100,1253.

[0311] 6) Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157.

[0312] 7)Cheng, HN, Macromolecules 17 (1984), 1950.

[0313] 8)Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475.

[0314] 9) Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150.

[0315] 10) Randall, J. Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.

[0316] 11) Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253.

[0317] Intrinsic viscosity

[0318] The intrinsic viscosity (iV) is measured in accordance with DIN ISO 1628 / 1, October 1999, in decalin at 135°C.

[0319] F 30 Melt strength and v 30 Melt ductility

[0320] The tests described in this article follow ISO 16790:2005.

[0321] The strain hardening behavior is determined by the method described in the article "Rheotens-Mastercurves and Drawability of Polymer Melts" by MH Wagner, Polymer Engineering and Science, Vol. 36, pp. 925 to 935. The content of this document is included by reference. The strain hardening behavior of the polymer was determined by a Rheotens apparatus (Buchen, Germany). 2, 74711 Siemensstr. 2), in which the melt strand is elongated by pulling it at a defined acceleration.

[0322] The Rheotens experiment simulates the industrial spinning and extrusion process. In principle, the melt is pressed or extruded through a circular die, and the resulting strand is pulled. The stress on the extrudate is recorded, which varies with the melt properties and the measured parameters (especially the ratio between the output and pulling speeds, which is actually a measure of the stretching rate). For the results given below, the material was extruded using a laboratory extruder HAAKE Polylab system and a gear pump with a cylindrical die (L / D=6.0 / 2.0mm). The gear pump was pre-adjusted to a strand extrusion rate of 5mm / s, and the melt temperature was set to 200°C. The spinning path length between the die and the Rheotens wheel was 80mm. At the beginning of the experiment, the winding speed of the Rheotens wheel was adjusted to the speed of the extruded polymer strand (pulling force was zero): the experiment was then started by slowly increasing the winding speed of the Rheotens wheel until the polymer filament broke. The acceleration of the wheel is small enough so that the pulling force can be measured under quasi-steady-state conditions. The acceleration of the melt strand pulling is 120mm / s 2 Rheotens operates in combination with the PC program EXTENS. This is a real-time data acquisition program that displays and stores the measured data of the pulling force and the pulling speed. The end points of the Rheotens curve (force vs. pulley speed) are taken as F 30 Melt strength and stretchability values.

[0323] density

[0324] Density was measured according to ISO 1183-187. Sample preparation was performed by compression molding according to ISO 1872-2:2007.

[0325] Density of foam

[0326] This has been measured using an analytical and semi-micro precision balance (Swiss Specific Gravimetry Balance (XS225A)) from PRECISA Gravimetrics AG, Switzerland; Test method: Applying the Archimedean principle, the density of the sample is automatically calculated.

[0327] Foam cell size diameter

[0328] The cell size diameter of the foam was determined using optical microscopy using a Tawain CBS stereo microscope;

[0329] The test methods used are as follows:

[0330] 1. Cut strips of foam material in the cross direction (CD) and machine direction (MD).

[0331] 2. Use a flat clamp to clamp the foam material and use a razor blade for fine trimming (shave).

[0332] 3. Focus the microscope at 100x magnification and adjust the illumination on the foam material.

[0333] 4. Measure the length and width of each single cell in both CD and MD directions and record the values.

[0334] 5. Count the number of single cells measured and record the value.

[0335] 6. Measure the cell wall thickness at 3 to 4 tangent lines throughout the total length of each single cell in CD and MD directions and record the values.

[0336] 7. Make three total strip thickness measurements starting from the bottom of the first measured cell group, to the middle of the cell group, and to the top of the cell group.

[0337] 8. Measure the total length starting from the lowest intact cell to the highest intact cell.

[0338] 9. Move the microscope field of view so that the bottom of the uppermost incomplete cell touches the bottom of the screen.

[0339] 10. Repeat steps 4 through 9 for each new single cell until a strip of approximately 0.200" to 0.800" has been measured. Make sure the total length and cell composition do not overlap. Each total length measurement after the first is taken from the top of the previous tallest complete cell to the top of the current tallest complete cell.

[0340] Flexural modulus

[0341] Flexural modulus according to ISO 178 at 23°C on 80×10×4 mm injection molded according to EN ISO 1873-2 3 Determined by 3-point bending on a test bar.

[0342] Puncture energy and energy to maximum force

[0343] The puncture energy and energy to maximum force were measured according to ISO 6603-2 using an instrumented drop weight impact test on a specimen made from injection molding with dimensions of 60×60×3 mm. 3The test is carried out at 23°C or -20°C (as indicated) using a lubricated tip with a diameter of 20 mm and an impact speed of 4.4 mm / s. Six specimens are tested for each sample, and the six force-deflection curves obtained are used to calculate the energy to maximum force and the average value of the puncture energy. In addition, the impact failure type is evaluated. ISO6603-2 defines the following impact failure types, and the numbers in brackets are assigned as the numerical values ​​for calculating the impact failure (the average value obtained from the six tested samples):

[0344] YD yield (slope is zero at maximum force), followed by deep drawing (1)

[0345] YS yield (slope zero at maximum force), followed by (at least partial) stable cracking (2)

[0346] YU yield (slope is zero at maximum force), followed by unstable cracking (3)

[0347] NY did not yield (4).

[0348] GPC-VISC-MALS analysis (branching index)

[0349] GPC measurements

[0350] A gel permeation chromatograph (GPC) manufactured by PolymerChar (Valencia, Spain) was used, which was equipped with an infrared detector (IR5), an online four-capillary bridge viscometer and a multi-angle light scattering (MALS) detector (Dawn Helios 2) with 18 angles in the range of about 22.5° to 147.0° from Wyatt Technology (Santa Barabara, USA). 3x Olexis and lx Olexis guard columns from Agilent were used as stationary phases and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L of 2,6-di-tert-butyl-4-methylphenol) was used as mobile phase at 160°C and at a constant flow rate of 1 mL / min. The polymer samples were dissolved in TCB at a concentration of 1 mg / ml at 160°C for 150 min. 200 μl of polymer solution was injected for each analysis. The injection concentration (c 160℃ ) is determined as follows.

[0351] GPC-VISC-MALS

[0352] The IV detector was calibrated with NIST 1475a using a nominal IV of 1.01 dl / g. The inter-detector volumes between the different detectors, concentration (IR), LS and viscometer detectors, were achieved by analyzing a narrow distribution of PS standards with a molar mass of 30000 g / mol.

[0353] For the determination of MWD using the GPC-VISC-MALS technique, a narrow distribution of PS standards with a molar mass of 30,000 g / mol was used to obtain normalization for the different MALS angles. The MALS detector was calibrated with a certified PE standard NIST1475a with a Mw of 54,000 g / mol at a laser wavelength (λ0) of 660 nm using a dn / dc of 0.094 ml / mg. For the calculation of the molecular weight, a laser wavelength (λ0) of 660 nm and a dn / dc of 0.094 ml / mg of PP in TCB solution were used. Due to the high baseline noise and frequent interferences, the MALS signals of the minimum 3 angles were not used in all calculations. Due to the low sample concentration used, the second Virial coefficient (A2=0) was neglected. The absolute Mw and the corresponding radius of gyration (R) of each chromatographic slice were obtained from the slope and intercept of the Debye plot. g ) (Reference: Wyatt, PJ (1993) Analy. Chim. Acta, Light Scattering and the Absolute Characterisation of Macromolecules. 272, 1-40). Zimm's formula is used to extrapolate the corresponding Rayleigh ratio (R(θ)) at different angles.

[0354] The molecular weight averages (Mz(LS), Mw(LS) and Mn(LS)), the molecular weight distribution (MWD) and its breadth described by the polydispersity PD(LS)=Mw(LS) / Mn(LS) (where Mn(LS) is the number average molecular weight and Mw(LS) is the weight average molecular weight obtained from GPC-LS) were calculated by gel permeation chromatography (GPC) using the following formula:

[0355]

[0356] For a constant elution volume interval ΔV i , where A i and M i(LS) and the elution volume V i Correlate the chromatographic peak slice areas and polyolefin molecular weight (MW) determined by GPC-MALS.

[0357] The corresponding subject IV (subject) and subject M wThe (body) value is calculated as follows:

[0358]

[0359]

[0360] The area IR ,area LSzero and area SpVisc are the area of ​​the concentration signal (IR5), the area of ​​the extrapolated LS signal at 0° and the area of ​​the specific viscosity. KIV and K(MALS) are the corresponding detector constants.

[0361] GPC routine

[0362] The column set was calibrated using a universal calibration of 19 polystyrene (PS) standards with narrow molecular weight distribution (MWD) in the range of 0.5 kg / mol to 11 500 kg / mol. The PS standards were dissolved at 160°C for 30 min. The conversion of polystyrene peak molecular weight to the corresponding polyolefin molecular weight was achieved by using the Mark Houwink equation and the corresponding Mark Houwink constant:

[0363] K PS =19×10 -3 mL / g, α PS =0.655

[0364] K PP =19×10 -3 mL / g, α PP =0.725

[0365] K PE =39×10 -3 mL / g, α PP =0.725

[0366] A third-order polynomial fit was used to fit the calibration data.

[0367] The molecular weight averages (Mz, Mw and Mn), the molecular weight distribution (MWD) and its breadth described by the polydispersity index PDI = Mw / Mn (where Mn is the number average molecular weight and Mw is the weight average molecular weight) are determined by gel permeation chromatography (GPC) using the following formula:

[0368]

[0369] For a constant elution volume interval ΔV i , where A i and M i and the elution volume V iCorrelate the chromatographic peak slice area and the polyolefin molecular weight (MW).

[0370] Branching index (gpcBR index):

[0371] The gpcBR index is calculated by using the following formula:

[0372]

[0373] All GPC calculations were performed using PolymerChar's GPCone software.

[0374] 2. Experiment

[0375] a) Polymerization of the heterophasic propylene copolymer (A)

[0376] The heterophasic propylene copolymer A used in the present invention is polymerized using the polymerization conditions given in Table 1 using techniques well known in the art.

[0377] The catalyst used in HECO A is an emulsion Ziegler-Natta catalyst, which is the same as the catalyst used in the polymerization of the inventive example of WO 2017 / 148970 Al.

[0378] The cocatalyst was TEAL and the external donor was dicyclopentyldimethoxysilane (donor D).

[0379] After polymerization under the conditions given in Table 1, the reactor produced polymer was supplemented with standard polypropylene additives as shown at the bottom of Table 1. Also given in Table 1 are the properties of the supplemented HECO A.

[0380] Table 1: Polymerization conditions and properties of HECO A

[0381]

[0382]

[0383] Talc was manufactured by IMI-Fabi (Italy) with an average particle size d50 of 2.4 μm, a cut-off particle size d95 of 7.7 μm and a particle size of 21 μm. 2 / g of specific surface area of ​​HM2.

[0384] GlySt glyceryl stearate, CAS-No. 31556-31-1, which is commercially available from Danisco (DuPont Group)

[0385] Irganox B 215 A 2:1 blend of Irgafox 168 and Irganox 1010, acting as a process and long-term heat stabilizer, commercially available from BASF SE

[0386] CaSt calcium stearate, CAS-No. 1592-23-0, which is commercially available from Faci

[0387] b) Blended composition and unfoamed sample

[0388] According to the formulations given in Table 2, unfoamed compositions according to the invention and comparative compositions IC1, IC2 and CC3 were prepared.

[0389] Thus, in a first step, the components were melt blended in a co-rotating twin-screw extruder in the amounts indicated in Table 1. The polymer melt mixture was discharged and pelletized.

[0390] In the second step, the pelletized polymer melt mixture was injection molded on an Engel E380 machine to produce injection molded plaques having the thicknesses listed in Table 2 below.

[0391] PPH B is a commercially available high melt strength propylene homopolymer Daploy from Borealis AG TM WB140HMS.

[0392] PE C is a commercially available ethylene-octene plastomer Queo 7001LA from Borealis AG having a melt flow rate MFR2 of 1 g / 10 min, 870 kg / m 3 density and a melting temperature of 56°C.

[0393] The properties of the final composition and the properties of the unfoamed plaques are given in Table 2.

[0394] Table 2: Composition and properties of unfoamed samples IC1, IC2 and CC3

[0395] Compounding IC1 IC2 CC3 HECO A [weight%] 90 80 100 PPH B [weight%] 10 10 - PE C [weight%] - 10 - performance Thickness of the sample [mm] 1.90 1.89 1.89 <![CDATA[MFR2]]> [g / 10min] 26 20 35 density <![CDATA[[kg / m 3 ]]]> 907.1 907.5 908.5 Flexural modulus [MPa] 1719 1443 1526 Tensile modulus [MPa] 1744 1448 1667 Tensile strain at break [％] 16.85 54.14 30.66 Tensile strain at tensile strength [％] 4.37 5.65 4.23 Tensile strain at yield [％] 4.37 5.65 4.23 Tensile Strength [MPa] 30.04 25.77 28.18 Tensile stress at break [MPa] 20.82 19.85 18.87 Yield tensile stress [MPa] 30.04 25.77 28.18 Energy to maximum force [J] 15.90 14.49 15.11 Maximum force [N] 2458 2171 2288 Piercing Energy [J] 23.01 26.45 24.38

[0396] c) Branching index of the melt blended polypropylene composition

[0397] The inventive melt-blended polypropylene compositions B, C and D and the comparative melt-blended polypropylene compositions A, E and F were prepared according to the recipes given in Table 3. The branching index was determined according to the GPC-VISC-MALS analysis described herein above.

[0398] Table 3:

[0399] Example HECO A PPH Branching index [weight%] [weight%] A Reference 100 0 0 B The present invention 95 5 0.06 C The present invention 90 10 0.14 D The present invention 80 20 0.28 E Reference 70 30 0.41 F Reference 0 100 1.52

[0400] d) Foaming the composition and the foamed sample

[0401] Injection molding foaming was carried out on an Engel E380 machine by introducing a pelletized polymer melt mixture having the composition as listed above in Table 2 for the unfoamed compositions IC1, IC2 and CC3 and a chemical blowing agent CFA1, CFA 2 or CFA 3 in the amount as listed below in Table 3. The material was foamed using the core back technique from a starting thickness of 2 mm to a final thickness as listed in Table 3.

[0402] CFA1 Chemical blowing agent Panthelene H65C, commercially available from EIWA CHEMICAL IND. CO., LTD. CFA2 Chemical blowing agent Panthelene H25C, commercially available from EIWA CHEMICAL IND. CO., LTD. CFA 3 Chemical blowing agent Maxithen HP 788810 / 20TR, commercially available from Gabriel-Chemie GmbH.

[0403] The properties of the foamed specimens are given in Table 4.

[0404] From the properties in Table 4 below, it can be seen that depending on the chemical blowing agent, the puncture energy can be increased at a comparable flexural modulus (CFA 3) or the flexural modulus can be increased at a comparable puncture energy (CFA 1 and CFA 2). Thus, the introduction of the copolymer of ethylene PE 3 improves the puncture energy.

[0405] Furthermore, the introduction of CFA 3 resulted in a higher density reduction.

[0406] Table 4: Composition and properties of foamed panels of Examples IE1 to IE6 and CE1 to CE3

[0407]

[0408] nm not measured.

Claims

1. A polypropylene composition having a melt flow rate MFR2 measured according to ISO 1133 at a temperature of 230° C. and a load of 2.16 kg of 10.0 to 55.0 g / 10 min, The polypropylene composition comprises (A) 55.0 to 97.5 wt.-%, preferably 65.0 to 96.5 wt.-%, more preferably 70.0 to 95.0 wt.-%, based on the total weight of the composition, of a heterophasic propylene copolymer comprising a matrix phase and an elastomeric phase dispersed in the matrix phase and having a xylene cold soluble (XCS) fraction in an amount of 10.0 to 25.0 wt.-%, preferably 11.5 to 22.5 wt.-%, more preferably 12.5 to 20.0 wt.-%, based on the total amount of the heterophasic propylene copolymer (A); (B) 2.5 to 25.0 wt.-%, preferably 3.5 to 20.0 wt.-%, more preferably 5.0 to 15.0 wt.-%, based on the total weight of the composition, of a high melt strength propylene homopolymer having a melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230 °C and a load of 2.16 kg, of 0.5 to 5.0 g / 10 min, preferably 1.0 to 3.0 g / 10 min and more preferably 1.2 to 2.5 g / 10 min; (C) 0 to 20.0 wt. %, preferably 0 to 15.0 wt. %, more preferably 0 to 12.5 wt. % of a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, based on the total weight of the composition, the copolymer having a molecular weight of 860 to 880 kg / m 3 , preferably 862 to 877 kg / m 3 , more preferably 865 to 875 kg / m 3 A density determined according to ISO 1183 of 0.1 to 2.5 g / 10 min, preferably 0.2 to 2.0 g / 10 min, more preferably 0.5 to 1.5 g / 10 min, determined according to ISO 1133 at a temperature of 190° C. and a load of 2.16 kg.

2. The polypropylene composition according to claim 1, wherein the composition has 890 to 1100 kg / m 3 density determined in accordance with ISO 1183; and / or • A melt flow rate MFR2, measured according to ISO 1133 at a temperature of 230° C. and a load of 2.16 kg, of 15.0 to 50.0 g / 10 min, preferably of 17.0 to 45.0 g / 10 min.

3. The polypropylene composition according to claim 1 or 2, wherein the composition has one or more of the following properties, or all of the following properties: a tensile modulus measured according to ISO 527-1 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1800 MPa; and / or 10 to 75%, more preferably 12 to 70%, still more preferably 15 to 60% of the tensile strain at break measured according to ISO 527-1; and / or a tensile strength measured according to ISO 527-1 of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa; and / or a tensile stress at break measured according to ISO 527-1 of 10 to 35 MPa, more preferably 13 to 30 MPa, still more preferably 15 to 25 MPa; and / or a flexural modulus measured according to ISO 178 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1750 MPa; and / or a puncture energy measured at 23°C according to ISO 6603-2 of 15 to 35 J, more preferably 18 to 32 J, still more preferably 20 to 30 J; and / or a maximum force at 23°C measured according to ISO 6603-2 at 23°C of 1750 to 2750 N, more preferably 2000 to 2600 N, still more preferably 2100 to 2500 N; and / or • Energy to Maximum Force at 23°C measured according to ISO 6603-2 at 23°C of 10 to 20 J, more preferably 12 to 18 J, still more preferably 13 to 17 J.

4. Polypropylene composition according to anyone of the preceding claims, wherein the heterophasic propylene copolymer (A) has one or more of the following properties, or all of the following properties: a melt flow rate, MFR2, measured at 230°C and a load of 2.16 kg according to ISO 1133-1 in the range of 15.0 to 100.0 g / 10 min, more preferably in the range of 20.0 to 90.0 g / 10 min, still more preferably in the range of 25.0 to 85.0 g / 10 min, most preferably in the range of 30.0 to 80.0 g / 10 min; and / or xylene cold soluble fraction (XCS) determined according to ISO 16152 at 25 °C present in an amount in the range of 8.0 to 25.0 wt.-%, more preferably in the range of 10.0 to 22.5 wt.-%, still more preferably in the range of 1 1.0 to 21.0 wt.-%, most preferably in the range of 12.5 to 20.0 wt.-%, based on the total weight of the heterophasic propylene copolymer (A); and / or an intrinsic viscosity (IV(XCS)) of the xylene cold soluble fraction determined in decalin according to DIN ISO 1628 / 1 in the range of 2.00 to 4.00 dl / g, more preferably in the range of 2.30 to 3.70 dl / g, still more preferably in the range of 2.50 to 3.40 dl / g, most preferably in the range of 2.70 to 3.30 dl / g; and / or · In the range of 20.0 to 60.0 wt. %, more preferably in the range of 25.0 to 50.0 wt. %, still more preferably in the range of 30.0 to 45.0 wt. %, most preferably in the range of 32.5 to 40.0 wt. % by quantitative 13 C{ 1 H}NMR measurement of the ethylene content of the xylene cold soluble fraction (C2(XCS)); and / or · in the range of 3.0 to 15.0 wt. %, more preferably in the range of 4.0 to 12.0 wt. %, still more preferably in the range of 5.0 to 10.0 wt. %, most preferably in the range of 6.0 to 8.5 wt. % by quantitative 13 C{ 1 H} NMR measurement was performed to measure the total ethylene content (C2).

5. Polypropylene composition according to anyone of the preceding claims, wherein the heterophasic propylene copolymer (A) comprises, preferably consists of, two heterophasic propylene copolymers (A-1 ) and (A-2), wherein the heterophasic propylene copolymer (A-1 ) has a lower melt flow rate MFR2 than the heterophasic propylene copolymer (A-2), and the weight ratio of heterophasic propylene copolymer (A-1 ) to heterophasic propylene copolymer (A-2) in the polypropylene composition is in the range of 40:60 to 60:40, preferably in the range of 45:55 to 55:

45.

6. Polypropylene composition according to anyone of the preceding claims, wherein the high melt strength propylene homopolymer (B) is branched and the branches are introduced into the polymer chain of the high melt strength propylene homopolymer (B) as side chains by polymerization in the presence of a single site catalyst or by chemical modification.

7. The polypropylene composition according to any of the preceding claims, wherein the high melt strength propylene homopolymer (B) has a melt strength F in the range of 20.0 to 50.0 cN, preferably in the range of 25.0 to 45.0 cN and more preferably in the range of 30.0 to 40.0 cN, such as in the range of 32.0 to 38.0 cN. 30 (ISO 16790:2005); and / or a melt ductility v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s and more preferably in the range of 230 to 280 mm / s, such as in the range of 240 to 280 mm / s 30 (ISO 16790:2005).

8. The polypropylene composition according to any of the preceding claims, wherein the ethylene copolymer (C) is a copolymer of ethylene and 1-octene comonomer units.

9. An injection moulded article comprising the polypropylene composition according to any one of the preceding claims.

10. The injection molded article according to claim 9, wherein the article has one or more of the following properties, or all of the following properties: a tensile modulus measured according to ISO 527-1 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1800 MPa; and / or ● a tensile strain at break measured according to ISO 527-1 of 10 to 75%, more preferably 12 to 70%, still more preferably 15 to 60%; and / or a tensile strength measured according to ISO 527-1 of 15 to 50 MPa, more preferably 20 to 45 MPa, still more preferably 23 to 40 MPa; and / or ● a tensile stress at break measured according to ISO 527-1 of 10 to 35 MPa, more preferably 13 to 30 MPa, still more preferably 15 to 25 MPa; and / or a flexural modulus measured according to ISO 178 of from 1200 to 2000 MPa, more preferably from 1300 to 1850 MPa, still more preferably from 1400 to 1750 MPa; and / or a puncture energy measured at 23°C according to ISO 6603-2 of 15 to 35 J, more preferably 18 to 32 J, still more preferably 20 to 30 J; and / or a maximum force at 23°C measured according to ISO 6603-2 at 23°C of 1750 to 2750 N, more preferably 2000 to 2600 N, still more preferably 2100 to 2500 N; and / or • Energy to Maximum Force at 23°C measured according to ISO 6603-2 at 23°C of 10 to 20 J, more preferably 12 to 18 J, still more preferably 13 to 17 J.

11. A foamed article, preferably a foamed injection molded article, comprising the polypropylene composition according to any one of claims 1 to 8.

12. The foamed article according to claim 11, wherein the polypropylene composition is foamed in the presence of a blowing agent, preferably a chemical blowing agent.

13. The foamed article according to claim 11 or 12, wherein the article has one or more of the following properties, or all of the following properties: 350 to 650 kg / m 3 , preferably 375 to 625 kg / m 3 , more preferably 400 to 600 kg / m 3 Density measured according to ISO 1183; Flexural modulus measured according to ISO 178 of 600 to 1200 MPa, preferably 650 to 1100 MPa, more preferably 675 to 1050 MPa; A tensile modulus measured according to ISO 527 of 350 to 800 mPa, preferably 375 to 775 MPa, more preferably 400 to 750 MPa; A tensile strain at break of 20 to 100%, more preferably 25 to 85%, still more preferably 32 to 70%; · a tensile strain at tensile strength measured according to ISO 527 of 2.0 to 7.5%, more preferably 2.5 to 7.0%, still more preferably 3.0 to 6.5%; 2.5 to 30.0%, more preferably 5.0 to 25.0%, still more preferably 7.5 to 20.0% tensile strain at yield measured according to ISO 527; a tensile strength measured according to ISO 527 of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa; - a tensile stress at break measured according to ISO 527 of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa; ● a tensile stress at yield measured according to ISO 527 of 5.0 to 20.0 MPa, more preferably 6.5 to 15.0 MPa, still more preferably 7.0 to 12.5 MPa; Energy to maximum force measured at 23°C according to ISO 6603-2 of 1.8 to 10.0 J, preferably 2.0 to 9.0 J; and / or • A puncture energy measured at 23° C. according to ISO 6603-2 of 2.0 to 10.0 J, preferably 2.3 to 9.0 J.

14. The foamed article according to any one of claims 11 to 13, wherein the flexural modulus measured according to ISO 178 is 500 to 1500 MPa lower than the flexural modulus of an unfoamed injection molded article measured according to ISO 178.

15. Use of the polypropylene composition according to any one of claims 1 to 8 and a chemical blowing agent for producing a foamed article, preferably a foamed injection molded article.

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