Polypropylene composition for preparing a foam and a foam containing the same

Abstract

The present application provides a polypropylene composition for preparing a foam. This polypropylene composition contains (a) a long-chain branched polypropylene and (b) a linear polypropylene, and this linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min. This linear polypropylene is present in this polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition. The present application further relates to a foam containing this polypropylene composition.

Description

Technical Field

[0001] The present application relates to a polypropylene composition for preparing a foam. The present application further relates to a foam comprising or obtainable from this polypropylene composition.

Background Art

[0002] Long-chain branched polypropylene is known for its combination of high melt strength and high melt drawability. Due to this combination of properties, these materials are particularly useful for foaming applications such as the preparation of low-density foams.

[0003] Polypropylene foams are known in the art. International Publication No. WO 2021 / 260097A1 pamphlet discloses a polypropylene composition comprising 10 to 50% by weight of recycled polypropylene and / or linear polypropylene, 40 to 89.95% by weight of a high melt strength polypropylene having an F 30 melt strength of more than 25.0 cN and a v 30 melt drawability of more than 205 mm / s, and 0.05 to 10% by weight of a nucleating agent (NA), and relates to a foamed sheet formed from the polypropylene composition.

[0004] U.S. Patent Application Publication No. US 2005 / 0165165A1 describes a polymer composition used in the production of foams. The polymer composition includes conventional linear polypropylene, high melt strength polypropylene, and a rheology modifier resin. The conventional linear polypropylene is present in an amount of about 1 to 25 weight percent of the polymer composition. The high melt strength polypropylene is present in an amount of about 51 to 85 weight percent of the polymer composition. The rheology modifier resin is a member of the group of styrene-olefin copolymers.

[0005] To obtain good foamability and high-quality foams, a typical approach in the art has been to maximize the melt strength and melt drawability of long-chain branched polypropylene or compositions containing it for good foaming.

[0006] However, increasing the melt strength significantly decreases the melt flow rate of the polymer. When the melt flow rate is low, the processability of the polymer under standard extrusion foaming conditions is limited. To process a polymer composition with a low viscosity (i.e., a low melt flow rate) at low shear, the output of the extruder can be decreased and / or the size of the extruder can be increased while maintaining the same output level. However, both approaches are costly and often not economically feasible.

[0007] To avoid the processing challenges of low melt flow rate polypropylene compositions and / or to increase the output of existing polypropylene foaming lines, a foaming polypropylene composition with good processability is needed. At the same time, the foaming polypropylene composition should be suitable for providing high-quality foams with good mechanical properties, such as high-quality low-density foams. Typically, high-quality foams have a low number of continuous cells, which is an indicator of a good cell structure.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] One object of the present invention is to provide a polypropylene composition for preparing a foam. One object of the present invention is to provide a foam comprising a polypropylene composition.

Means for Solving the Problems

[0010] One aspect of the present invention provides a polypropylene composition for preparing a foam. This polypropylene composition comprises (a) a long-chain branched polypropylene, and (b) a linear polypropylene and the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, and the linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition.

[0011] One finding of the present inventors is that the polypropylene composition described herein is suitable for preparing foams of good quality, specifically low-density foams of good quality. The polypropylene composition can be used to prepare foams having good and / or improved mechanical properties, such as, inter alia, longitudinal tensile strength and elongation at break, in combination with a good cell structure. When the polypropylene composition of the present invention is foamed, better processability due to a relatively high melt flow rate can be observed. This can contribute to a lower pressure level in the extruder. The viscosity of the polypropylene composition can allow the converter to reach a lower melt temperature, which in turn can allow the foam to reach a lower density.

[0012] These findings were surprising. This is because the use of a large amount of high melt flow rate linear polypropylene in combination with long-chain branched polypropylene was expected to have a significant adverse effect on the melt strength of the polypropylene composition, thereby degrading the quality of the foamed product.

[0013] Another aspect of the present invention provides a foam. This foam comprises a polypropylene composition according to one embodiment of the present invention.

[0014] According to one preferred embodiment of the present invention, up to 100 kg / m3 There is provided a foam having a density and comprising a polypropylene composition, and this polypropylene composition comprises (a) long-chain branched polypropylene, and (b) linear polypropylene, wherein the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, and the linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition.

[0015] Alternatively, the foam can be obtained from, or is obtained from, a polypropylene composition according to one embodiment of the present invention.

[0016] Another aspect of the present invention provides the use of a polypropylene composition according to one embodiment of the present invention for preparing a foam.

[0017] Another aspect of the present invention provides a process for preparing a foam. This process comprises a) providing a polypropylene composition according to one embodiment of the present invention, and b) foaming the polypropylene composition provided in step a) to obtain a foam and.

[0018] According to one preferred embodiment of the present invention, there is provided a process for preparing a foam having a density of up to 100 kg / m 3 and comprising a polypropylene composition, and this polypropylene composition comprises (a) long-chain branched polypropylene, and (b) linear polypropylene wherein the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, The linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition, and this process is a) a step of providing a polypropylene composition, wherein this polypropylene composition is (a) long-chain branched polypropylene, (b) having a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min and being present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition, the linear polypropylene comprising a step; b) a step of foaming the polypropylene composition provided in step a) to obtain a foam and comprising.

[0019] According to one embodiment of the present invention, the polypropylene composition is (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) optionally, 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and all amounts by weight are based on the total weight of the polypropylene composition. Optionally, components (a) to (c) together amount to 100% by weight.

[0020] According to one embodiment of the present invention, the polypropylene composition does not contain a styrene-based polymer.

[0021] According to one embodiment of the present invention, the polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 6.0 to 30.0 g / 10 min, preferably in the range of 6.0 to 25.0 g / 10 min.

[0022] According to one embodiment of the present invention, the long-chain branched polypropylene is a long-chain branched polypropylene homopolymer.

[0023] According to one embodiment of the present invention, the long-chain branched polypropylene is preferably obtained by treating linear polypropylene with a radical-forming agent in the presence of a difunctional unsaturated monomer (multiple types possible) and / or a polyfunctional unsaturated low molecular weight polymer (multiple types possible).

[0024] According to one embodiment of the present invention, the linear polypropylene is a matrix of polypropylene, preferably a propylene homopolymer or a propylene copolymer, and an elastomeric ethylene copolymer, preferably a C2C3 copolymer, dispersed in the above matrix and is a heterophasic polypropylene composition.

[0025] According to one embodiment of the present invention, the above heterophasic polypropylene composition has a cold xylene soluble fraction (at 25 °C according to ISO 16152) in the range of 10.0 to 45.0 wt%, preferably in the range of 12.0 to 30.0 wt%, more preferably in the range of 12.0 to 22.0 wt% based on the total weight of this heterophasic polypropylene composition.

[0026] According to one embodiment of the present invention, the above elastomeric ethylene copolymer, preferably a C2C3 copolymer, has an ethylene content in the range of 25.0 to 70.0 wt%, preferably in the range of 25.0 to 65.0 wt%, more preferably in the range of 28.0 to 58.0 wt% based on the total weight of this elastomeric ethylene copolymer.

[0027] According to one embodiment of the present invention, the above long-chain branched polypropylene has the following properties 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, more preferably in the range of 30.0 to 40.0 cN 30 (ISO16790:2005), ii) A melt drawability v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s, more preferably in the range of 230 to 280 mm / s 30 (ISO16790:2005), iii) A melt flow rate MFR2 (ISO1133, 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, more preferably in the range of 1.2 to 2.5 g / 10 min having one or more, preferably two or more, more preferably all of the above.

[0028] According to one embodiment of the present invention, the above linear polypropylene has a melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 15.0 to 125.0 g / 10 min, preferably in the range of 20.0 to 100.0 g / 10 min, more preferably in the range of 25.0 to 70.0 g / 10 min, most preferably in the range of 25.0 to 40.0 g / 10 min.

[0029] According to one embodiment of the present invention, the foam has a maximum density of 100 kg / m 3 , preferably in the range of 30 to 100 kg / m 3 and has a density in the range of.

[0030] According to one embodiment of the present invention, the foam has the following properties i) A melt strength F of up to 20.0 cN 30 (ISO16790:2005), ii) A shear thinning index SHI determined as described herein, with a maximum of 40.0, preferably in the range of 10.0 to 35.0, more preferably in the range of 10.0 to 30.0 (0.05 / 300) having one or both of the above.

[0031] According to one embodiment of the present invention, the foam has the following properties i) a closed cell content measured according to ASTM D6226 of up to 50%, preferably in the range of 5 to 45%, ii) an elongation at break measured in the machine direction (MD) according to ISO1798 of at least 10%, preferably in the range of 10 to 20%, and iii) a tensile strength measured in the machine direction (MD) according to ISO1798 of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa and has one or more, preferably two or more, more preferably all of the above properties.

[0032] When the term "comprising" is used in this specification and claims, it does not exclude other unspecified elements, whether functionally important or not. For the purposes of the present invention, the terms "essentially consisting of" and "consisting of" are considered to be specific embodiments of the term "comprising". In the following, when a group is defined as including at least a number of features or embodiments, this should also be understood to optionally disclose a group consisting essentially of or consisting only of these features or embodiments. Whenever the terms "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above.

[0033] The present invention will be described in more detail below.

Embodiments for Carrying out the Invention

[0034] A polypropylene composition for preparing a foam One aspect of the present invention provides a polypropylene composition for preparing a foam. This polypropylene composition (a) Long-chain branched polypropylene, and (b) Linear (unbranched) polypropylene and contains. The linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min. This linear polypropylene is present in this polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition.

[0035] The polypropylene composition provided herein is suitable for preparing foams. "Suitable for preparing foams" includes, for example, polypropylene compositions that can be foamed by using a physical blowing agent provided externally in an extrusion foaming process. Therefore, "suitable for preparing foams" should be understood in the sense that the polypropylene composition does not necessarily contain a blowing agent (however, this is possible).

[0036] According to one preferred embodiment, the polypropylene composition is suitable for preparing foams by an extrusion foaming process using a physical blowing agent (such as a gas like butane).

[0037] The polypropylene composition is not only suitable for preparing foams, but is not limited to the preparation of foams. Other uses and applications of the polypropylene composition provided herein are also contemplated and not excluded.

[0038] Long-chain branched polypropylene (a) The polypropylene composition contains long-chain branched polypropylene as component (a). The long-chain branched polypropylene present in the polypropylene composition according to the present invention is also referred to herein as "long-chain branched polypropylene (a)".

[0039] Long-chain branched polypropylene is known in the art. Long-chain branched polypropylene contains long side chains in the polypropylene backbone, which is different from linear polypropylene, i.e., unbranched polypropylene, which does not contain long side chains. The long side chains branching from the polymer main chain have a significant impact on the rheology of polypropylene. Therefore, linear polypropylene and long-chain branched polypropylene can be clearly distinguished, for example, by their flow behavior under stress (e.g., the ratio of polymer melt viscosities measured under different loads). Additionally or alternatively, long-chain branching can be determined by analyzing the content of long-chain branches by NMR and / or by measuring the long-chain branching index g' by using, for example, SEC / VISC-LS (size exclusion chromatography / viscosity measurement - light scattering) known in the art. The branching index g' is a parameter of the degree of branching. The branching index g' correlates with the amount of branching of the polymer. A low g' value is an indicator of a highly branched polymer. That is, as the g' value decreases, the branching of polypropylene increases. For example, a g' value of at least 0.96, for example at least 0.97 or at least 0.98, typically indicates the absence of long-chain branches. On the other hand, a g' value of less than 0.9 (e.g., 0.6 - 0.9), for example less than 0.8, typically indicates that the polymer contains long-chain branches. Further details regarding the branching index g' and its determination method are described, for example, in the "Measuring methods" section of European Patent No. 3280748B1, which is incorporated herein by reference.

[0040] Due to certain melt strength characteristics, long-chain branched polypropylene is also referred to as high melt strength polypropylene in the art.

[0041] Long-chain branching can usually be achieved by using specific catalysts, namely specific single-site catalysts and / or metallocene catalysts, or by chemical modification. For the preparation of long-chain branched polypropylene obtained by using specific catalysts, reference is made to European Patent Application Publication No. 1892264. For long-chain branched polypropylene obtained by chemical modification, reference is made to, for example, European Patent Application Publication No. 0787750, European Patent Application Publication No. 0879830A1, and European Patent Application Publication No. 0890612A2.

[0042] Long-chain branched polypropylene typically has a relatively low melt flow rate in combination with high melt strength and high melt extensibility.

[0043] The polypropylene composition contains at least one long-chain branched polypropylene (a), for example 1 to 3 long-chain branched polypropylenes (a). For example, the polypropylene composition can contain one long-chain branched polypropylene (a).

[0044] The long-chain branched polypropylene (a) is not limited in principle as long as it is suitable for preparing the polypropylene composition according to one embodiment of the present invention.

[0045] The long-chain branched polypropylene is not particularly limited with respect to the linear polypropylene forming its longest chain or backbone. The long-chain branched polypropylene (a) may be a long-chain branched propylene copolymer or a long-chain branched propylene homopolymer.

[0046] The long-chain branched polypropylene (a) may be a long-chain branched propylene copolymer such as a long-chain branched propylene random copolymer. When the long-chain branched polypropylene (a) is a propylene copolymer, the propylene copolymer contains ethylene and / or C4 - C 10It may contain a comonomer selected from the group consisting of α-olefins, such as 1-butene and / or 1-hexene, and ethylene and / or 1-butene is preferred. For example, the long-chain branched propylene copolymer may be a long-chain branched C2C3 copolymer.

[0047] The comonomer content of the long-chain branched propylene copolymer may be in the range of more than 0.5 to 10.0 mol%, and more preferably in the range of more than 0.5 to 7.0 mol%.

[0048] The long-chain branched polypropylene (a) is preferably a long-chain branched propylene homopolymer. Therefore, according to one preferred embodiment of the present invention, the long-chain branched polypropylene (a) is a long-chain branched propylene homopolymer.

[0049] When the long-chain branched polypropylene is a long-chain branched polypropylene obtained by chemical modification of linear polypropylene, the definitions of propylene homopolymer and propylene copolymer refer to, for example, the linear polypropylene used to obtain long-chain branched polypropylene by chemical modification using a bifunctional unsaturated monomer (multiple types possible) and / or a polyfunctional unsaturated low molecular weight polymer (multiple types possible) in reactive extrusion.

[0050] The polypropylene composition typically contains a specific minimum amount of long-chain branched polypropylene to impart sufficient melt strength to this composition.

[0051] The polypropylene composition typically contains at least 20.0% by weight of long-chain branched polypropylene (a) based on the total weight of the polypropylene composition. Preferably, the polypropylene composition contains at least 30.0% by weight, more preferably at least 35.0% by weight, and even more preferably at least 37.5% by weight of long-chain branched polypropylene based on the total weight of the polypropylene composition.

[0052] The polypropylene composition preferably contains 20.0 to 70.0% by weight, more preferably 30.0 to 70.0% by weight, even more preferably 35.0 to 65.0% by weight, for example 37.5 to 62.5% by weight of the long-chain branched polypropylene (a) based on the total weight of the polypropylene composition.

[0053] The long-chain branched polypropylene (a) preferably has specific properties such as viscosity and melt strength.

[0054] The long-chain branched polypropylene (a) preferably 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, more preferably in the range of 30.0 to 40.0 cN, for example in the range of 32.0 to 38.0 cN. 30 (ISO16790:2005).

[0055] The long-chain branched polypropylene (a) preferably has a melt drawability v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s, more preferably in the range of 230 to 280 mm / s, for example in the range of 240 to 280 mm / s. 30 (ISO16790:2005).

[0056] The long-chain branched polypropylene (a) preferably has a melt flow rate MFR2 (ISO1133, 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, more preferably in the range of 1.2 to 2.5 g / 10 min, for example in the range of 1.4 to 2.3 g / 10 min.

[0057] According to one preferred embodiment, the long-chain branched polypropylene (a) has the following properties 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, more preferably in the range of 30.0 to 40.0 cN, for example in the range of 32.0 to 38.0 cN. 30 (ISO16790:2005), ii) a melt drawability v in the range of 190 to 320 mm / s, preferably 210 to 300 mm / s, more preferably 230 to 280 mm / s, for example in the range of 240 to 280 mm / s 30 (ISO 16790:2005), 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 1.0 to 3.0 g / 10 min, more preferably 1.2 to 2.5 g / 10 min, for example in the range of 1.4 to 2.3 g / 10 min has two or more, more preferably all, of the above.

[0058] The long-chain branched polypropylene (a) can 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.

[0059] The long-chain branched polypropylene (a) can preferably be obtained by treating linear polypropylene with a radical-forming agent in the presence of a difunctional unsaturated monomer(s) and / or a polyfunctional unsaturated low-molecular-weight polymer(s).

[0060] The radical former may be a peroxide, preferably an organic peroxide such as a thermally decomposable organic peroxide. The polyfunctional unsaturated low molecular weight polymer preferably has a number average molecular weight (Mn) of 10,000 g / mol or less. A suitable low molecular weight polymer is polybutadiene, preferably polybutadiene having a microstructure that is partially or mainly in the 1,2-(vinyl) configuration. The difunctional unsaturated monomer may be selected from divinyl compounds, allyl compounds, dienes, etc. Preferably, the difunctional unsaturated monomer is selected from the group consisting of 1,3-butadiene, isoprene, dimethylbutadiene, divinylbenzene, and mixtures thereof. Suitable methods for obtaining unused long chain branched PP are disclosed, for example, in European Patent Application Publication No. 0787750A2, European Patent Application Publication No. 0879830A1, and European Patent Application Publication No. 0890612A2.

[0061] A suitable long chain branched polypropylene (a) is WB140HMS (trademark), commercially available from Borealis AG.

[0062] Linear polypropylene (b) The polypropylene composition contains linear polypropylene as component (b). The linear polypropylene present in the polypropylene composition according to the present invention is also referred to herein as "linear polypropylene (b)".

[0063] Linear polypropylene is also known in the art. Linear polypropylene differs from long-chain branched polypropylene in that the polypropylene chains essentially do not contain side chains, i.e., are not branched. A person skilled in the art can distinguish between linear polypropylene and long-chain branched polypropylene. For example, as described above, linear polypropylene and long-chain branched polypropylene can be clearly distinguished by their flow behavior under stress. The presence of branches in polypropylene may also be determined, for example, by using gel phase chromatography (GPC) to determine the branching index. As is known in the art, linear polypropylene can be produced, for example, by using a suitable single-site catalyst or a Ziegler-Natta catalyst.

[0064] One requirement is that the linear polypropylene (b) has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, preferably at least 20 g / 10 min, more preferably at least 25.0 g / 10 min.

[0065] According to one preferred embodiment of the present invention, the linear polypropylene (b) has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 15.0 to 125.0 g / 10 min, preferably 20.0 to 100.0 g / 10 min, more preferably 25.0 to 70.0 g / 10 min, most preferably 25.0 to 40.0 g / 10 min, for example in the range of 28.0 to 36.0 g / 10 min.

[0066] The polypropylene composition contains at least one kind of linear polypropylene (b), for example 1 to 3 kinds of linear polypropylene (b). The linear polypropylene (b) is not particularly limited in terms of chemical composition as long as it meets the requirement of the minimum melt flow rate and is suitable for preparing the polypropylene composition according to the present invention.

[0067] The linear polypropylene (b) is not particularly limited in terms of chemical composition.

[0068] The linear polypropylene (b) may be a propylene copolymer, for example, a propylene random copolymer. When the linear polypropylene (b) is a propylene copolymer, the linear polypropylene (b) may contain ethylene and / or a comonomer selected from the group consisting of C4-C 10 α-olefins, such as 1-butene and / or 1-hexene, and ethylene and / or 1-butene are preferred. For example, the linear polypropylene (b) may be a C2C3 copolymer. The comonomer content of the linear polypropylene (b) may be in the range of more than 0.5 to 10.0 mol%, more preferably in the range of more than 0.5 to 7.0 mol%.

[0069] Alternatively, the linear polypropylene (b) may be a linear propylene homopolymer. Therefore, according to one preferred embodiment of the present invention, the linear polypropylene (b) is a linear propylene homopolymer.

[0070] In one preferred embodiment of the present invention, the linear polypropylene (b) is a heterophasic polypropylene composition. Such heterophasic polypropylene compositions are known in the art.

[0071] The heterophasic polypropylene composition preferably comprises a matrix which is polypropylene, more preferably a homopolymer or copolymer of propylene, and which is preferably (semi)crystalline. An elastomeric ethylene copolymer is dispersed in this matrix. Thus, the matrix contains a (finely) dispersed admixture which is not part of the matrix, and this admixture contains an elastomeric ethylene copolymer. The term "admixture" indicates that the matrix and this admixture form different phases within the heterophasic polypropylene composition. The presence of the second phase or so-called admixture can be seen, for example, by high-resolution microscopy, such as electron microscopy or atomic force microscopy, or by dynamic mechanical thermal analysis (DMTA). Specifically, in DMTA, the presence of a multiphase structure can be identified by the presence of at least two distinguishable glass transition temperatures.

[0072] According to one embodiment, the heterophasic polypropylene composition comprises a matrix which is a propylene homopolymer and an elastomeric ethylene copolymer dispersed in this matrix.

[0073] The heterophasic polypropylene composition, based on the total weight of this heterophasic polypropylene composition · a matrix of polypropylene, preferably a propylene homopolymer or propylene copolymer, in the range of 55.0 to 90.0% by weight, more preferably 70.0 to 88.0% by weight, even more preferably 75.0 to 88.0% by weight, for example 78.0 to 88.0% by weight, and · an elastomeric ethylene copolymer in the range of 10.0 to 45.0% by weight, more preferably 12.0 to 30.0% by weight, even more preferably 12.0 to 25.0% by weight, for example 12.0 to 22.0% by weight is preferably included, more preferably consists of these.

[0074] For example, the heterophasic polypropylene composition can include, and preferably can consist of, a matrix of about 82% by weight of polypropylene and about 18% by weight of an elastomeric ethylene copolymer.

[0075] The above heterophasic polypropylene composition preferably has a cold xylene soluble fraction (at 25 °C according to ISO 16152) in the range of 10.0 to 45.0% by weight, preferably in the range of 12.0 to 30.0% by weight, more preferably in the range of 12.0 to 22.0% by weight, based on the total weight of the heterophasic polypropylene composition.

[0076] The above elastomeric ethylene copolymer can include any comonomer copolymerizable with ethylene. Preferably, the elastomeric ethylene copolymer is a copolymer of ethylene and at least one monomer selected from the group of C3 - C 12 α-olefins, more preferably selected from the group of propylene, 1-butene, 1-hexene and 1-octene, and most preferably a copolymer of ethylene and propylene (i.e., a C2C3 copolymer).

[0077] The above elastomeric ethylene copolymer, preferably the elastomeric C2C3 copolymer, can have an ethylene content in the range of 25.0 to 70.0% by weight, preferably in the range of 25.0 to 65.0% by weight, more preferably in the range of 28.0 to 58.0% by weight, for example in the range of 30.0 to 40.0% by weight, or in the range of 50.0 to 58.0% by weight, based on the total weight of the elastomeric ethylene copolymer.

[0078] For example, the ethylene content of the above elastomeric ethylene copolymer, preferably the elastomeric C2C3 copolymer, can be about 54% by weight based on the total weight of the elastomeric ethylene copolymer.

[0079] According to one more preferred embodiment, the above-mentioned elastomeric ethylene copolymer, preferably the elastomeric C2C3 copolymer, has an ethylene content in the range of 30.0 to 40.0% by weight based on the total weight of this elastomeric ethylene copolymer.

[0080] A suitable heterophasic polypropylene composition is the product "PP612MK10" commercially available from SABIC.

[0081] The polypropylene composition contains at least 30.0% by weight of linear polypropylene (b) based on the total weight of the polypropylene composition. Preferably, the polypropylene composition contains at least 35.0% by weight, more preferably at least 37.5% by weight of linear polypropylene (b) based on the total weight of the polypropylene composition.

[0082] It is more preferable that the polypropylene composition contains 30.0 to 80.0% by weight, more preferably 30.0 to 70.0% by weight, even more preferably 35.0 to 65.0% by weight, and still even more preferably 37.5 to 62.5% by weight of linear polypropylene (b) based on the total weight of the polypropylene composition.

[0083] Additive (c) The polypropylene composition may contain one or more additives as component (c). This polypropylene composition can contain one additive, or two or more additives, for example 2 to 6 additives, 2 to 4 additives. For example, the polypropylene composition can contain one or two additives.

[0084] The additives may vary depending on the use of the polypropylene composition, the equipment for processing the polypropylene composition, and / or the products containing the polypropylene composition, preferably the applications of the foam. The additives can be selected by those skilled in the art.

[0085] The polypropylene composition can contain one or more additional polymer components as additive (c) or as part of additive (c). The one or more additional polymer components may be polymer components that are melt blendable with the long-chain branched polypropylene (a) and the linear polypropylene (b). For example, the additional polymer component may be a polymer material that is introduced into the polypropylene composition as part of an additive masterbatch, i.e., as a polymer carrier material.

[0086] However, it is also possible to select the polymer carrier material of the additive masterbatch to be very similar to or essentially identical to one of components (a) and (b).

[0087] The polypropylene composition may be prepared using an additive masterbatch containing a nucleating agent and a polymer carrier resin, such as a polypropylene carrier resin. The polymer carrier resin may be the same as or different from the remaining polymer component (a) or (b).

[0088] The polypropylene composition preferably contains a nucleating agent such as a talc nucleating agent as an additive. Nucleating agents are known to those skilled in the art. According to one preferred embodiment, the polypropylene composition contains one or more additives as component (c), and the one or more additives contain a nucleating agent. Preferably, the nucleating agent is talc.

[0089] The polypropylene composition can contain 0.01 to 10.0% by weight of one or more additives (c) based on the total weight of the polypropylene composition.

[0090] The polypropylene composition preferably contains 0.01 to 5.0% by weight, more preferably 0.1 to 4.0% by weight, even more preferably 0.2 to 3.0% by weight, for example 0.2 to 2.0% by weight of one or more additives (c) based on the total weight of the polypropylene composition.

[0091] According to one preferred embodiment, the polypropylene composition contains 0.01 to 5.0% by weight, more preferably 0.1 to 4.0% by weight, even more preferably 0.2 to 3.0% by weight, for example 0.2 to 2.0% by weight of one or more additives (c) based on the total weight of the polypropylene composition, provided that one or more additives (c) contain a nucleating agent, that is, it is required that the nucleating agent is part of one or more additives (c), or is the above-mentioned one additive (c). This nucleating agent is preferably talc.

[0092] One or more additives (c) can contain a nucleating agent, preferably talc, in an amount of at least 50.0% by weight, preferably at least 60.0% by weight to 100% by weight based on the total weight of one or more additives (c). The remaining part of one or more additives (c) may be a polymer carrier resin, for example polypropylene suitable for use in a polymer masterbatch, but is not limited thereto.

[0093] According to one preferred embodiment, the polypropylene composition contains 0.01 to 5.0% by weight, more preferably 0.1 to 4.0% by weight, even more preferably 0.2 to 3.0% by weight, for example 0.2 to 2.0% by weight of a nucleating agent, preferably a talc nucleating agent based on the total weight of the polypropylene composition.

[0094] Polypropylene composition The polypropylene composition contains at least 30.0% by weight of linear polypropylene (b) based on the total weight of the polypropylene composition.

[0095] Preferably, the polypropylene composition contains long-chain branched polypropylene (a) and linear polypropylene (b) in amounts according to specific weights.

[0096] The polypropylene composition (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long-chain branched polypropylene and, (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene and can be included, and the amounts by all weights are based on the total weight of the polypropylene composition.

[0097] In addition to components (a) and (b), the polypropylene composition can further include other components, such as other polymer blend partners.

[0098] The polypropylene composition preferably contains a polymer material different from at least one long-chain branched polypropylene (a) and at least one linear polypropylene (b) in an amount of up to 10.0% by weight (e.g., 0.0 to 10.0% by weight), optionally up to 5.0% by weight (e.g., 0.0 to 5.0% by weight), and optionally up to 3.0% by weight (e.g., 0.0 to 3.0% by weight) based on the total weight of the polypropylene composition.

[0099] For example, the polypropylene composition can contain a polymer material different from at least one long-chain branched polypropylene (a) and at least one linear polypropylene (b) in an amount in the range of 0.2 to 3.0% by weight, optionally 0.2 to 2.0% by weight based on the total weight of the polypropylene composition. When the polypropylene composition contains the above small amount of additional polymer material, the polymer material may be the polymer carrier resin of the additive masterbatch.

[0100] The polypropylene composition does not need to contain a styrenic polymer in order to achieve the beneficial effects described herein. Styrenic polymers include, for example, hydrogenated styrene-isoprene-styrene block copolymer (SEPS), styrene-butadiene random copolymer, hydrogenated styrene-butadiene random copolymer, styrene-isoprene random copolymer, hydrogenated styrene-isoprene random copolymer, styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB, SEBC), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene copolymer, styrene-propylene copolymer, ethylene-styrene graft copolymer, propylene-styrene graft copolymer, EPM-styrene graft copolymer, EPDM-styrene graft copolymer, and combinations thereof.

[0101] Preferably, the polypropylene composition does not contain a styrenic polymer, such as a styrenic polymer selected from the group described above herein.

[0102] The polypropylene composition preferably contains one or more additives as component (c).

[0103] The polypropylene composition (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and can be included, and the amounts by all weights are based on the total weight of the polypropylene composition.

[0104] The polypropylene composition (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and can be included, and the amounts by all weights are based on the total weight of the polypropylene composition, and components (a) to (c) together amount to 100% by weight.

[0105] The polypropylene composition preferably (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and is included, and the amounts by all weights are based on the total weight of the polypropylene composition.

[0106] The polypropylene composition preferably (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and all amounts by weight are based on the total weight of the polypropylene composition, and components (a) to (c) together total 100% by weight.

[0107] According to one preferred embodiment, the polypropylene composition (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 79.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8.0% by weight, even more preferably 37.5 to 62.3% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and preferably consists essentially of or consists of these, and all amounts by weight are based on the total weight of the polypropylene composition.

[0108] In one more specific embodiment, the polypropylene composition (a) 55.0 to 64.8% by weight, such as 57.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 35.0 to 44.8% by weight, for example 37.5 to 62.3% by weight of linear polypropylene, and (c) 0.2 to 4.0% by weight, more preferably 0.2 to 2.0% by weight of one or more additives and including, the amounts by all weights being based on the total weight of the polypropylene composition, components (a) to (c) preferably total 100% by weight.

[0109] As described above, the one or more additives (c) preferably include a nucleating agent, more preferably a talc nucleating agent. For example, the polypropylene composition can include a nucleating agent, preferably a talc nucleating agent, as component (c).

[0110] The one or more additives (c) can include an additional polymer material, for example, additional polypropylene. For example, the polypropylene composition can include, as component (c), a nucleating agent, preferably a talc nucleating agent, and a polymer carrier resin, for example polypropylene.

[0111] The polypropylene composition is preferably defined by a relatively high melt flow rate as a foamed polypropylene composition.

[0112] According to one preferred embodiment of the present invention, the polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 6.0 to 30.0 g / 10 min, preferably in the range of 6.0 to 25.0 g / 10 min, for example in the range of 6.0 to 15.0 g / 10 min.

[0113] The polypropylene composition may be provided in a melt-mixed form or a dry blend form.

[0114] According to one embodiment, the polypropylene composition is provided in the form of a dry blend, i.e., in the form of a dry blend polypropylene composition. Dry blend polypropylene compositions are known in the art. A dry blend typically comprises the individual components (a)-(c) described hereinabove and further optional components in the form of a loose mixture of pellets.

[0115] When the polypropylene composition is provided in the form of a dry blend, it may be obtained, or can be obtained, by a dry blending process that includes, for example, mixing the components described herein in a batch dry blending apparatus.

[0116] Alternatively, the polypropylene composition can be provided in the form of a melt blend, i.e., in the form of a melt blend polypropylene composition. In this case, the composition may be obtained, or can be obtained, by a melt blending process that includes, for example, mixing the components described herein in a batch or continuous melt blending apparatus. The melt blending process may be part of an extrusion foaming process in which the melt blend polypropylene composition is provided to an extruder and then subjected to a subsequent foaming step.

[0117] The melt blend polypropylene composition may be present in a molten form (e.g., in an extruder) or in a solid form.

[0118] The polypropylene composition may be provided in the form of a dry blend. This dry blend (a) 20.0 to 70.0 wt%, preferably 30.0 to 70.0 wt%, more preferably 35.0 to 65.0 wt%, even more preferably 37.5 to 62.5 wt% of a long chain branched polypropylene, and (b) 30.0 to 80.0 wt%, preferably 30.0 to 70.0 wt%, more preferably 35.0 to 65.0 wt%, even more preferably 37.5 to 62.5 wt% of a linear polypropylene and can include, where all amounts are by weight based on the total weight of the dry blend.

[0119] When one or more optional additives are present in the dry blend as component (c), it is preferred that this additive be present in the form of an additive masterbatch. The additive masterbatch itself is known to those skilled in the art.

[0120] The dry blend (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin-containing additive masterbatch and can include, and all amounts by weight are based on the total weight of the polypropylene dry blend.

[0121] The above dry blend (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of long chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin, and can be included, and the amounts by all weights are based on the total weight of the dry blend, and components (a) to (c) together amount to 100% by weight.

[0122] The above dry blend (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin, and can be included, and the amounts by all weights are based on the total weight of the dry blend.

[0123] The above dry blend (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin, and can contain, and all amounts by weight are based on the total weight of the dry blend, and components (a) to (c) together are 100% by weight.

[0124] The above dry blend (a) 20.0 to 69.99% by weight, preferably 30.0 to 69.9% by weight, more preferably 35.0 to 64.8% by weight, even more preferably 37.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of linear polypropylene, and (c) 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin, and can contain, preferably consisting essentially of or consisting of these, and all amounts by weight are based on the total weight of the dry blend.

[0125] In one more specific embodiment, the above dry blend (a) 55.0 to 64.8% by weight, such as 57.5 to 62.3% by weight of long-chain branched polypropylene, and (b) 35.0 to 44.8% by weight, such as 37.5 to 62.3% by weight of linear polypropylene, and (c) 0.2 to 4.0% by weight, more preferably 0.2 to 2.0% by weight of an additive masterbatch, preferably (i) a nucleating agent, more preferably a talc nucleating agent, and (ii) a polymer carrier resin, preferably a propylene carrier resin, and comprising, with all amounts by weight based on the total weight of the polypropylene composition, components (a) to (c) preferably totaling 100% by weight.

[0126] Foam One aspect of the present invention provides a foam comprising a polypropylene composition according to one embodiment of the present invention.

[0127] Another aspect of the present invention provides a foam that can be obtained or is obtained by a polypropylene composition according to one embodiment of the present invention. For example, this foam may be or can be obtained from the polypropylene composition described herein, and this polypropylene composition is provided in the form of a dry blend.

[0128] According to one preferred embodiment, a foam having a density of up to 100 kg / m 3 is provided, comprising a polypropylene composition, which (a) long-chain branched polypropylene and (b) linear polypropylene and the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, and the linear polypropylene is present in this polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition.

[0129] The above polypropylene composition may be further defined by one or more embodiments of the polypropylene composition described herein in the section "Polypropylene composition for preparing a foam" including the section "Polypropylene composition", and recited in the appended claims. Components of the polypropylene composition, such as long-chain branched polypropylene (a), linear polypropylene (b) and additive (c), may also be further defined by one or more embodiments described above herein in the sections "Long-chain branched polypropylene (a)", "Linear polypropylene (b)" and "Additive (c)".

[0130] Preferably, the foam comprises at least 95.0% by weight, more preferably in the range of 98.0 to 100% by weight of the polypropylene composition based on the total weight of the foam. The foam preferably consists essentially of or consists of a polypropylene composition according to one embodiment of the present invention.

[0131] The foam preferably has a low density. According to one preferred embodiment, the foam has a density of up to 100 kg / m 3 , more preferably in the range of 30 to 100 kg / m 3 , optionally in the range of 30 to 80 kg / m 3 , for example in the range of 40 to 80 kg / m 3 .

[0132] The foam is preferably provided in the form of a foamed article, such as a foamed sheet. The foamed sheet can have a thickness of up to 10.0 mm, preferably in the range of 0.5 to 10.0 mm, for example in the range of 0.5 to 7.0 mm.

[0133] According to one preferred embodiment, the foam has a thickness of up to 10.0 mm, preferably in the range of 0.5 to 10.0 mm, for example in the range of 0.5 to 7.0 mm, and a density of up to 100 kg / m 3 , more preferably in the range of 30 to 100 kg / m 3 , for example in the range of 30 to 80 kg / m 3It is a foamed sheet having a density within the range of density.

[0134] The foam can have specific properties such as melt strength and shear thinning index.

[0135] Preferably, the foam has a melt strength F in the range of up to 20.0 cN, more preferably 5.0 to 20.0 cN 30 (ISO16790:2005).

[0136] Preferably, the foam has a shear thinning index SHI determined as described herein in the range of up to 40.0, preferably 10.0 to 35.0, more preferably 10.0 to 30.0 (0.05 / 300) having.

[0137] According to one preferred embodiment of the present invention, the foam has the following properties i) A melt strength F in the range of up to 20.0 cN, more preferably 5.0 to 20.0 cN 30 (ISO16790:2005), ii) A shear thinning index SHI determined as described herein in the range of up to 40.0, preferably 10.0 to 35.0, more preferably 10.0 to 30.0 (0.05 / 300) having both.

[0138] The foam preferably has a desirable foam structure that can be characterized by its open cell content. The open cell content of the foam, measured according to ASTM D6226, is preferably at most 50% (e.g., in the range of 5 to 50%), more preferably at most 45% (e.g., in the range of 5 to 45%), for example in the range of 25 to 40%.

[0139] The foam can also be characterized by its mechanical properties.

[0140] The foam can have an elongation at break measured in the longitudinal direction (machine direction, MD) according to ISO 1798 of at least 10%, preferably in the range of 10 to 20%, for example in the range of 10 to 15%. This foam can have an elongation at break measured in the transverse direction (cross direction, CD) according to ISO 1798 of at least 5%, preferably in the range of 5 to 20%, for example in the range of 10 to 15%.

[0141] In one embodiment, the foam has an elongation at break measured in the longitudinal direction (MD) according to ISO 1798 of at least 10%, preferably in the range of 10 to 20%, for example in the range of 10 to 15%, and an elongation at break measured in the transverse direction (CD) according to ISO 1798 of at least 5%, preferably in the range of 5 to 20%, for example in the range of 10 to 15%.

[0142] Furthermore, the foam may have a tensile strength measured in the longitudinal direction (MD) according to ISO 1798 of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa, for example in the range of 1250 to 1750 kPa.

[0143] The foam can have a tensile strength measured in the transverse direction (CD) according to ISO 1798 of at least 600 kPa, preferably in the range of 600 to 2000 kPa, for example in the range of 700 to 1500 kPa.

[0144] In one embodiment, the foam has a tensile strength measured in the longitudinal direction (MD) according to ISO 1798 of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa, and a tensile strength measured in the transverse direction (CD) according to ISO 1798 of at least 600 kPa, preferably in the range of 600 to 2000 kPa, for example in the range of 700 to 1500 kPa.

[0145] According to one embodiment, the foam has the following properties i) A continuous bubble content measured according to ASTM D6226, up to 50%, preferably in the range of 10 - 45%, for example in the range of 25 - 40%. ii) An elongation at break measured in the machine direction (MD) according to ISO1798, at least 10%, preferably in the range of 10 - 20%, for example in the range of 10 - 15%, and iii) A tensile strength measured in the machine direction (MD) according to ISO1798, at least 1050 kPa, preferably in the range of 1050 - 2000 kPa, for example in the range of 1250 - 1750 kPa having one or more, preferably two or more, more preferably all of the above.

[0146] Therefore, the foam has the following properties i) A continuous bubble content measured according to ASTM D6226, up to 50%, preferably in the range of 10 - 45%, for example in the range of 25 - 40%. ii) An elongation at break measured in the machine direction (MD) according to ISO1798, at least 10%, preferably in the range of 10 - 20%, for example in the range of 10 - 15%, and iii) A tensile strength measured in the machine direction (MD) according to ISO1798, at least 1050 kPa, preferably in the range of 1050 - 2000 kPa, for example in the range of 1250 - 1750 kPa and can have all of the above.

[0147] According to one more preferred embodiment, the foam has the following properties i) A continuous bubble content measured according to ASTM D6226, up to 50%, preferably in the range of 10 - 45%, for example in the range of 25 - 40%. ii) An elongation at break measured in the machine direction (MD) according to ISO1798, at least 10%, preferably in the range of 10 - 20%, for example in the range of 10 - 15%, and iii) A tensile strength measured in the machine direction (MD) according to ISO1798, at least 1050 kPa, preferably in the range of 1050 - 2000 kPa, for example in the range of 1250 - 1750 kPa, iv) A shear thinning index SHI determined as described herein, with a maximum of 40.0, preferably in the range of 10.0 to 35.0, more preferably in the range of 10.0 to 30.0 (0.05 / 300) and having all of the following

[0148] In one more specific embodiment, the foam has the following properties i) An elongation at break measured in the machine direction (MD) and cross direction (CD) according to ISO 1798, of at least 10%, preferably in the range of 10 to 20%, for example in the range of 10 to 15%, and ii) A tensile strength measured in the machine direction (MD) according to ISO 1798, of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa, for example in the range of 1050 to 1250 kPa, iii) A tensile strength measured in the machine direction (MD) according to ISO 1798, of at least 700 kPa, preferably in the range of 700 to 2000 kPa, for example in the range of 700 to 950 kPa and having all of the following

[0149] In one more specific embodiment, the foam has the following properties i) An elongation at break measured in the machine direction (MD) and cross direction (CD) according to ISO 1798, of at least 10%, preferably in the range of 10 to 20%, for example in the range of 10 to 15%, and ii) A tensile strength measured in the machine direction (MD) according to ISO 1798, of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa, for example in the range of 1050 to 1250 kPa, iii) A tensile strength measured in the machine direction (MD) according to ISO 1798, of at least 700 kPa, preferably in the range of 700 to 2000 kPa, for example in the range of 700 to 950 kPa, iv) A closed cell content measured according to ASTM D6226, with a maximum of 50%, preferably in the range of 10 to 45%, for example in the range of 25 to 40% and having all of the following

[0150] In these specific embodiments, the foam can include a more specific polypropylene composition as described above, including 55.0 to 64.8 wt% of long-chain branched polypropylene (a) and 35.0 to 44.8 wt% of linear polypropylene (b).

[0151] Use of the polypropylene composition In another aspect, the present invention provides the use of a polypropylene composition according to one embodiment of the present invention for preparing a foam.

[0152] Regarding the possible and preferred embodiments of the polypropylene composition used for preparing the foam, reference is made to the embodiments and preferred embodiments described above herein.

[0153] In one embodiment, the present invention provides a process for preparing a foam in which a polypropylene composition according to one embodiment of the present invention is used.

[0154] Process for preparing a foam Another aspect of the present invention provides a process for preparing a foam, preferably as described above herein.

[0155] This process comprises a) providing a polypropylene composition according to one embodiment of the present invention; and b) foaming the polypropylene composition provided in step a) to obtain a foam. and includes.

[0156] According to one preferred embodiment of the present invention, there is provided a process for preparing a foam having a density of up to 100 kg / m 3 and comprising a polypropylene composition, this polypropylene composition comprising (a) long-chain branched polypropylene; and (b) linear polypropylene comprising, wherein the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, the linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition, and the process a) providing a polypropylene composition, wherein the polypropylene composition (a) long chain branched polypropylene, (b) linear polypropylene having a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min and present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition comprising; b) foaming the polypropylene composition provided in step a) to obtain a foam and comprising.

[0157] The process is preferably an extrusion foaming process. Such processes are known in the art. The process is not limited to a specific extrusion foaming process. The extrusion foaming process may be carried out in a single extruder foaming system or a tandem foam extrusion line.

[0158] The process is preferably an extrusion foaming process using a tandem foam extrusion line. Such equipment is known in the art. A tandem extrusion line typically includes a primary extruder, such as a co-rotating twin screw extruder for compounding and incorporating a blowing agent, and a secondary extruder, such as a single screw extruder for cooling the foamable melt.

[0159] More preferably, the extrusion foaming process uses a tandem foam extrusion line suitable for preparing a foam having a density of up to 100 kg / m 3 of.

[0160] Preferably, the polypropylene composition is provided in the form of a melt blend, for example in a melt blending apparatus, preferably in an extruder, in step a).

[0161] More preferably, step a) comprises a1) dry blending long-chain branched polypropylene (a), linear polypropylene (b), optionally one or more additives (c), and optionally further components to obtain a polypropylene composition in the form of a dry blend; a2) melt blending the dry blend provided in step a1). and includes.

[0162] In a preferred embodiment, one or more additives (c) are present in step a1), for example in the form of an additive masterbatch. It is more preferred that additional components other than components (a)-(c) are essentially absent in step a1).

[0163] Step a1) preferably relates to dry blending long-chain branched polypropylene (a), linear polypropylene (b) and one or more additives (c) to obtain a polypropylene composition in the form of a dry blend.

[0164] The melt blending step a2) can be carried out in any suitable melt blending apparatus, preferably in an extruder of a foam extrusion line. The process conditions and equipment can be selected and adjusted by those skilled in the art as needed.

[0165] Step b) relates to foaming the polypropylene composition provided in step a), preferably the melt blended polypropylene composition, to obtain a foam. Foaming can be achieved by a chemical blowing agent and / or a physical blowing agent.

[0166] Step b) is preferably carried out using a physical blowing agent. The physical blowing agent is typically a gas suitable for foaming the polymer melt. The gas may be butane but is not limited thereto.

[0167] Physical blowing agents are typically injected into the polymer melt, for example, during melt mixing in the primary extruder of a tandem foam extrusion line. Thereafter, optionally after passing through the secondary extruder of the tandem foam extrusion line, the foaming melt is subjected to foaming to obtain a foam.

[0168] Without in any way limiting the foregoing disclosure, further aspects and embodiments of the present invention are defined in the following non-limiting numbered items [1] through

[15] .

[0169] [1] A polypropylene composition for preparing a foam, wherein the polypropylene composition comprises (a) long-chain branched polypropylene, and (b) linear polypropylene wherein the linear polypropylene has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 15.0 g / 10 min, and the linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition.

[0170] [2] The polypropylene composition comprises (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of the long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of the linear polypropylene, and (c) optionally, 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives The polypropylene composition according to item [1], which contains the following components and the amounts by all weights are based on the total weight of the polypropylene composition, and optionally, components (a) to (c) together amount to 100% by weight.

[0171] [3] The polypropylene composition according to item [1] or item [2], wherein the polypropylene composition does not contain a styrene polymer.

[0172] [4] The polypropylene composition according to any one of items [1] to [3], which has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 6.0 to 30.0 g / 10 min, preferably in the range of 6.0 to 25.0 g / 10 min.

[0173] [5] The polypropylene composition according to any one of items [1] to [4], wherein the long-chain branched polypropylene is a long-chain branched polypropylene homopolymer.

[0174] [6] The linear polypropylene is a matrix of polypropylene, preferably a propylene homopolymer or a propylene copolymer, and an elastomeric ethylene copolymer, preferably a C2C3 copolymer, dispersed in the matrix and is a heterophasic polypropylene composition. The polypropylene composition according to any one of items [1] to [5].

[0175] [7] The heterophasic polypropylene composition has a cold xylene-soluble fraction (at 25 °C according to ISO 16152) in the range of 10.0 to 45.0% by weight, preferably in the range of 12.0 to 30.0% by weight, more preferably in the range of 12.0 to 22.0% by weight, based on the total weight of the heterophasic polypropylene composition. The polypropylene composition according to item [6].

[0176] [8] The elastomeric ethylene copolymer, preferably a C2C3 copolymer, has an ethylene content determined by quantitative NMR spectroscopy as described in the method section herein, in the range of 25.0 to 70.0% by weight, preferably in the range of 25.0 to 65.0% by weight, more preferably in the range of 28.0 to 58.0% by weight, based on the total weight of the elastomeric ethylene copolymer, of the polypropylene composition according to item [6] or item [7].

[0177] [9] The long-chain branched polypropylene has the following properties 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, more preferably in the range of 30.0 to 40.0 cN 30 (ISO16790:2005), ii) A melt drawability v in the range of 190 to 320 mm / s, preferably in the range of 210 to 300 mm / s, more preferably in the range of 230 to 280 mm / s 30 (ISO16790:2005), iii) A melt flow rate MFR2 (ISO1133, 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, more preferably in the range of 1.2 to 2.5 g / 10 min of one or more, preferably two or more, more preferably all, of the polypropylene compositions according to any one of items [1] to [8].

[0178]

[10] The linear polypropylene has a melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 15.0 to 125.0 g / 10 min, preferably in the range of 20.0 to 100.0 g / 10 min, more preferably in the range of 25.0 to 70.0 g / 10 min, most preferably in the range of 25.0 to 40.0 g / 10 min, of the polypropylene composition according to any one of items [1] to [9].

[0179]

[11] A foam containing the polypropylene composition according to any one of items [1] to

[10] .

[0180]

[12] A maximum of 100 kg / m 3 , preferably in the range of 30 to 100 kg / m 3 of the foam according to item

[11] , having a density measured according to ISO 845.

[0181]

[13] The following properties i) A melt strength F of a maximum of 20.0 cN, preferably in the range of 5.0 to 20.0 cN 30 (ISO 16790:2005), ii) A shear thinning index SHI determined as described herein, of a maximum of 40.0, preferably in the range of 10.0 to 35.0, more preferably in the range of 10.0 to 30.0 (0.05 / 300) of the foam according to item

[11] or item

[12] , having one or both of them.

[0182]

[14] The following properties i) A continuous cell content measured according to ASTM D6226, of a maximum of 50%, preferably in the range of 5 to 45%, ii) An elongation at break measured in the longitudinal direction (MD) according to ISO 1798, of at least 10%, preferably in the range of 10 to 20%, and iii) A tensile strength measured in the longitudinal direction (MD) according to ISO 1798, of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa of the foam according to any one of items

[11] to

[13] , having one or more of them, preferably two or more, more preferably all.

[0183]

[15] A process for preparing a foam, a) Providing a polypropylene composition according to any one of items [1] to

[10] ; and b) Foaming the polypropylene composition provided in step a) to obtain a foam The process includes these steps.

Examples

[0184] Method Melt Flow Rate (MFR): The Melt Flow Rate MFR was determined in accordance with ISO 1133 at a temperature of 230°C under a load of 2.16 kg.

[0185] Melt Strength F30 and Melt Drawability v30: The tests described in this specification are in accordance with ISO 16790:2005. The tests were carried out at a pressure of 30 bar (barg).

[0186] The strain hardening behavior is determined by the method described in the paper "Rheotens-Mastercurves and Drawability of Polymer Melts", M.H. Wagner, Polymer Engineering and Science, Vol. 36, pages 925-935. The content of this document is incorporated by reference. The strain hardening behavior of the polymer is analyzed by a Rheotens apparatus (product of Goettfert, Siemensstr. 2, 74711 Buchen, Germany). In this apparatus, the strand of the melt is stretched by pulling it down at a specified acceleration.

[0187] The Rheotens experiment simulates industrial spinning and extrusion processes. In principle, the melt is compressed or extruded through a circular die and the resulting strand is drawn off. The stress applied to the extrudate is recorded as a function of the melt properties and the measurement parameters (notably the ratio of output to draw-off speed, practically a measure of the elongation rate). For the results shown below, the material was extruded using an experimental extruder HAAKE Polylab system and a gear pump equipped with a cylindrical die (L / D = 6.0 / 2.0 mm). The gear pump was pre-adjusted so that the extrusion speed of the strand was 5 mm / s and the melt temperature was set at 200 °C. The spinline length between the die and the Rheotens wheel was 80 mm. At the start of the experiment, the take-up speed of the Rheotens wheel was adjusted to the speed of the extruded polymer strand (zero tensile force). Then, the experiment was started by slowly increasing the take-up speed of the Rheotens wheel until the polymer filament broke. The acceleration of the wheel was made small enough so that the tensile force was measured in a quasi-steady state. The acceleration of the drawn-down melt strand was 120 mm / s 2 . This Rheotens was operated in combination with the PC program "EXTENS". This is a real-time data acquisition program that displays and saves the measured data of the tensile force and the draw-down speed. The end point of the Rheotens curve (force vs. pulley rotation speed) was taken as F 30 the values of the melt strength and the drawability.

[0188] Shear thinning index SHI (0.05 / 300) : The characterization of the polymer melt by dynamic shear measurements is carried out in accordance with ISO standards 6721-1 and 6721-10. The measurements were performed using an Anton Paar MCR501 stress-controlled rotational rheometer equipped with a 25 mm parallel plate configuration. The measurements were carried out using a nitrogen atmosphere, setting the strain within the linear viscoelastic region and using compression-molded plates. The oscillatory shear tests were carried out at 200 °C with a gap of 1.3 mm and applying a frequency range of 0.01 - 600 rad / s.

[0189] In the dynamic shear experiment, the probe is subjected to uniform deformation with a sinusoidally varying shear strain or shear stress (in the modes of controlling strain and stress respectively). In the controlled strain experiment, the probe is subjected to a sinusoidal strain that can be expressed by the following formula. γ(t)=γ0sin(ωt) (1) If the applied strain is within the range of the linear viscoelastic region, the resulting sinusoidal stress response can be given by the following formula. σ(t)=σ0sin(ωt+δ) (2) In the above formulas, σ0 and γ0 are the stress amplitude and strain amplitude respectively, ω is the angular frequency, δ is the phase difference (the loss angle between the applied strain and the stress response), and t is the time.

[0190] The results of the dynamic test are typically several different rheological functions, namely the shear storage modulus G’, the shear loss modulus G”, the complex shear modulus G * , the complex shear viscosity η * , the dynamic shear viscosity η’, the out-of-phase component η” of the complex shear viscosity, and the loss tangent tanη. These rheological functions can be expressed as follows.

Equation

[0191] The determination of the so-called shear thinning index, which correlates with MWD and is independent of Mw, is carried out as described in Equation 9.

Equation

[0192] The values of the storage modulus (G’), the loss modulus (G”), the complex modulus (G * ) and the complex viscosity (η * ) were obtained as functions of the frequency (ω).

[0193] Therefore, for example, η * 300rad / s (eta * 300rad / s ) is used as an abbreviation for the complex viscosity at a frequency of 300 rad / s, and η * 0.05rad / s (eta * 0.05rad / s ) is used as an abbreviation for the complex viscosity at a frequency of 0.05 rad / s.

[0194] The loss tangent tan(δ) is defined as the ratio of the loss modulus (G”) to the storage modulus (G’) at a given frequency. Thus, for example, tan 0.05 is used as an abbreviation for the ratio of the loss modulus (G”) to the storage modulus (G’) at 0.05 rad / s, and tan 300 is used as an abbreviation for the ratio of the loss modulus (G”) to the storage modulus (G’) at 300 rad / s.

[0195] The elasticity balance tan 0.05 / tan 300 is defined as the ratio of the loss tangent tan 0.05 to the loss tangent tan 300 .

[0196] In addition to the above rheological functions, other rheological parameters such as the so-called elasticity index EI(x) can also be determined. The elasticity index EI(x) is the value of the storage modulus (G’) determined for the value of the loss modulus (G”) at x kPa, and can be described by Equation 10. EI(x) = G’ [Pa] for (G” = x kPa) (10)

[0197] For example, EI(5 kPa) is defined by the value of the storage modulus (G’) determined for the value of G” equal to 5 kPa.

[0198] The viscosity η 747 is measured at a very low constant shear stress of 747 Pa and is inversely proportional to the gravity flow of the polyethylene composition, i.e., η 747The higher the [value], the lower the sagging of the polyethylene composition.

[0199] The polydispersity index PI is defined by Equation 11. [Number] In the above formula, ω COP is the crossover angular frequency and is determined as the angular frequency at which the storage modulus G’ is equal to the loss modulus G”.

[0200] The [value] is determined by a single-point interpolation procedure defined by Rheoplus software. In situations where the experimentally reached [value] for a given G * value is not reached, the [value] is determined by extrapolation using the same procedure as before. In both cases (interpolation or extrapolation), the options “Interpolate y-values to x-values from parameter” and “logarithmic interpolation type” from Rheoplus were applied.

[0201] References: [1] “Rheological characterization of polyethylene fractions”, Heino, E.L., Lehtinen, A., Tanner J., Seppala, J., Neste Oy, Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th (1992), 1, 360 - 362 [2] “The influence of molecular structure on some rheological properties of polyethylene”, Heino, E.L., Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995. [3] "Definition of terms relating to the non-ultimate mechanical properties of polymers", Pure & Appl.Chem., Vol. 70, No. 3, pp. 701-754, 1998.

[0202] Cold xylene soluble (XCS) fraction: The cold xylene soluble fraction (XCS, wt%) can be determined at 25 °C according to ISO 16152; 5th edition; 2005-07-01.

[0203] Determination of C2 and C3 contents in PP copolymers: Quantitative nuclear magnetic resonance (NMR) spectroscopy can be used to quantify the comonomer content and comonomer sequence distribution of the polymer. Quantitative 13 C{ 1 H} NMR spectra are 1 H and 13 C can be recorded in solution using a Bruker Avance III 400 NMR spectrometer operating at 400.15 MHz and 100.62 MHz for 13Using a 10 mm extended temperature probe head optimized for C, nitrogen gas can be used to record for all pressures. Approximately 200 mg of the substance is dissolved in 3 ml of 1,2 - tetrachloroethane - d2 (TCE - d2) together with chromium(III) acetylacetonate (Cr(acac)3) giving a 65 mM solution of the relaxant in the solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5(2009), 475). To ensure a homogeneous solution, after the initial sample preparation in a heat block, the NMR tube is further heated in a rotary oven for at least 1 hour. After insertion into the magnet, the tube is rotated at 10 Hz. This setting can be chosen mainly for the high resolution and quantitativeness necessary for the accurate quantification of the ethylene content. Using an optimized tip angle, a recycle delay of 1 s and a bilinear 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 standard single - pulse excitation without NOE can be employed. A total of 6144 (6k) transient signals may be acquired per spectrum.

[0204] Quantitative 13 C{ 1The 1H NMR spectra may be processed, integrated, and the relevant quantitative characteristics determined from the integral values using a proprietary computer program. All chemical shifts can be 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 referencing even when this structural unit may not be present. Characteristic signals corresponding to the incorporation of ethylene can be observed (Cheng, H. N., Macromolecules 17 (1984), 1950).

[0205] The comonomer fraction can be 13 quantified by integrating multiple signals over the entire spectral region of the 13C{ 1 1H} spectrum using the method of Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000) 1157). This method may be chosen because of its robustness and the ability to account for the presence of positional defects if necessary. The integration region is adjusted slightly to enhance applicability over the full range of comonomer contents encountered. For systems where only isolated ethylene in the PPEPP sequence is observed, the method of Wang et al. may be modified to reduce the effect of non-zero integrals at sites known to be absent. This approach reduces overestimation of the ethylene content for such systems, which is achieved by reducing the number of sites used to determine the absolute ethylene content to E = 0.5(Sββ + Sβγ + Sβδ + 0.5(Sαβ + Sαγ)) This is accomplished by reducing it to Using this set of sites, the corresponding integral equation, using the same notation as used in the paper by Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157), is E = 0.5(I H + I G + 0.5(I C + I D )) The equation used for the absolute propylene content is not modified. The comonomer incorporation in mole percent can be calculated from the mole fraction. E [mol%] = 100 × fE The comonomer incorporation in weight percent can be calculated from the mole fraction. E [wt%] = 100 × (fE × 28.06) / ((fE × 28.06) + ((1 - fE) × 42.08))

[0206] Foam density: The foam density was measured in accordance with ISO 845 using a semi-micro precision balance for analysis from PRECISA Gravimetrics AG, Switzerland.

[0207] Closed cell content: The closed cell content was determined in accordance with ASTM D6226.

[0208] Tensile strength and elongation: The tensile strength and elongation at break in the machine direction (MD) and the cross direction (CD) were determined in accordance with ISO 1798.

[0209] Starting materials Long-chain branched polypropylene starting material (b-PP): The long-chain branched polypropylene starting material (b-PP) was the commercially available product Daploy WB140HMS from Borealis AG. This polymer had a melt flow rate of 2.1 g / 10 min (ISO 1133, 2.16 kg load, 230 °C), a melt strength F of about 34 cN 30 (ISO 16790:2005), and a melt drawability v of about 260 mm / s 30 (ISO 16790:2005).

[0210] Linear polypropylene (l-PP): L-PP-1: A propylene homopolymer available from Borealis AG as HE125MO. This polymer had a melt flow rate of 12 g / 10 min (ISO 1133, 2.16 kg load, 230 °C). L-PP-2: A heterophasic propylene composition comprising a polypropylene matrix and an elastomeric C2C3 copolymer dispersed therein (about 18 wt% C2C3 rubber content; about 54 wt% C2 content in the rubber phase). This polymer is available from SABIC as PP612MK10. This polymer has a melt flow rate of 33 g / 10 min (ISO1133, 2.16 kg load, 230 °C).

[0211] Additive masterbatch (AM): A commercially available additive masterbatch (AM) was used. The additive masterbatch contains about 70 wt% talc nucleating agent and about 30 wt% polypropylene as a carrier resin. This polypropylene has a melt index of about 4 g / 10 min (230 °C / 2.16 kg).

[0212] Examples The following dry blends were prepared. Comparative Example CE1: 99.2 wt% b-PP + 0.8 wt% AM Comparative Example CE2: 59.0 wt% b-PP + 40.0 wt% l-PP-1 + 1.0 wt% AM Comparative Example CE3: 49.0 wt% b-PP + 50.0 wt% l-PP-1 + 1.0 wt% AM Comparative Example CE4: 39.0 wt% b-PP + 60.0 wt% l-PP-1 + 1.0 wt% AM Inventive Example IE1: 59.0 wt% b-PP + 40.0 wt% l-PP-2 + 1.0 wt% AM Inventive Example IE2: 49.0 wt% b-PP + 50.0 wt% l-PP-2 + 1.0 wt% AM Inventive Example IE3: 39.0 wt% b-PP + 60.0 wt% l-PP-2 + 1.0 wt% AM

[0213] Using the above dry blends, low-density polypropylene foams were prepared using a KraussMaffei Berstorff tandem foaming line (ZE40 twin-screw extruder; KE90 single-screw extruder) and isobutane as the foaming agent.

[0214] The foaming agent was used in an amount in the range of 3.5 to 7.0% by weight. The twin-screw extruder was operated at a temperature in the range of 20 to 220°C, a screw speed in the range of 100 to 200 r / min, and a specific output in the range of 0.2 to 0.7 kg / h / r / min. The single-screw extruder was operated at a temperature in the range of 20 to 190°C, a screw speed in the range of 2 to 15 r / min, and a specific output in the range of 5 to 20 kg / h / r / min.

[0215] The foam properties are summarized in Table 1 below.

[0216] [Table 1]

[0217] Examples IE1 to IE3 in Table 1 show that the production of low-density polypropylene foams is possible using a commercial extrusion foaming process. Linear polypropylene can be added to the blend in an amount up to 60% by weight. Furthermore, Examples IE1 to IE3 in Table 1 show improved processability (lower pressure levels in the melt extruder and the cooling extruder) compared to Example CE1. The continuous cell content of Examples IE1 to IE3 is as low as that of the foam of Example CE1 and lower than that of Examples CE2 to CE4. This result confirms a better foam structure for Examples IE1 to IE3 compared to Examples CE2 to CE4. In addition, Examples IE1 to IE3 show an improvement in the balance of foam rigidity and elongation at break, especially in the longitudinal direction.

[0218] Therefore, the above results show that Invention Examples IE1 to IE3 provide foams having an improved cell structure and a better balance of mechanical properties than the foams produced from the comparative blends.

Claims

1. A maximum of 100 kg / m ３ and having a density of, a foam containing a polypropylene composition, wherein the polypropylene composition is (a) a long-chain branched polypropylene, and (b) a linear polypropylene including, wherein the linear polypropylene has a melt flow rate MFR of at least 15.0 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C). The linear polypropylene is present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition, a foam.

2. The polypropylene composition (a) 20.0 to 70.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of the long-chain branched polypropylene, and (b) 30.0 to 80.0% by weight, preferably 30.0 to 70.0% by weight, more preferably 35.0 to 65.0% by weight, even more preferably 37.5 to 62.5% by weight of the linear polypropylene, and (c) optionally, 0.01 to 5.0% by weight, preferably 0.1 to 4.0% by weight, more preferably 0.2 to 3.0% by weight, even more preferably 0.2 to 2.0% by weight of one or more additives and all amounts by weight are based on the total weight of the polypropylene composition, and optionally, components (a) to (c) together are 100% by weight, the foam according to Claim 1.

3. The polypropylene composition does not contain a styrene-based polymer, the foam according to Claim 1 or Claim 2.

4. The polypropylene composition has a melt flow rate MFR in the range of 6.0 to 30.0 g / 10 min, preferably in the range of 6.0 to 25.0 g / 10 min ２ The foam according to any one of claims 1 to 3, having ２ (ISO 1133, 2.16 kg load, 230°C).

5. The long-chain branched polypropylene is a long-chain branched polypropylene homopolymer, the foam according to any one of Claims 1 to 4.

6. The linear polypropylene a matrix that is polypropylene, preferably a propylene homopolymer or a propylene copolymer, and an elastomeric ethylene copolymer, preferably a C2C3 copolymer, dispersed in the matrix is a heterophasic polypropylene composition, the foam according to any one of Claims 1 to 5.

7. The heterophasic polypropylene composition has a cold xylene-soluble fraction (at 25 °C according to ISO 16152) in the range of 10.0 to 45.0% by weight, preferably in the range of 12.0 to 30.0% by weight, more preferably in the range of 12.0 to 22.0% by weight based on the total weight of the heterophasic polypropylene composition, the foam according to Claim 6.

8. The elastomeric ethylene copolymer, preferably a C2C3 copolymer, has an ethylene content determined by quantitative NMR spectroscopy as described in the method section of the specification in the range of 25.0 to 70.0% by weight, preferably in the range of 25.0 to 65.0% by weight, more preferably in the range of 28.0 to 58.0% by weight, based on the total weight of the elastomeric ethylene copolymer. The foam according to claim 6 or claim 7.

9. The long-chain branched polypropylene has one or more of the following properties 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, more preferably in the range of 30.0 to 40.0 cN ３０ (ISO 16790:2005), ii) A melt drawability v in the range of 190 to 320 mm / s, preferably 210 to 300 mm / s, more preferably 230 to 280 mm / s ３０ (ISO 16790:2005), iii) Melt flow rate MFR in the range of 0.5 to 5.0 g / 10 min, preferably 1.0 to 3.0 g / 10 min, more preferably 1.2 to 2.5 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C) The foam according to any one of claims 1 to 8, having two or more, more preferably all of them.

10. The long-chain branched polypropylene is preferably obtained by treating linear polypropylene with a radical former in the presence of a bifunctional unsaturated monomer and / or a polyfunctional unsaturated low molecular weight polymer. The foam according to any one of claims 1 to 9.

11. The linear polypropylene has a melt flow rate MFR in the range of 15.0 to 125.0 g / 10 min, preferably 20.0 to 100.0 g / 10 min, more preferably 25.0 to 70.0 g / 10 min, and most preferably 25.0 to 40.0 g / 10 min. ２ The foam according to any one of claims 1 to 10, having ２ (ISO 1133, 2.16 kg load, 230 °C).

12. The foam according to any one of claims 1 to 11, comprising at least 95% by weight, preferably in the range of 98.0 to 100% by weight, of the polypropylene composition based on the total weight of the foam.

13. A density measured according to ISO 845 in the range of 30 to 100 kg / m ３ The foam according to any one of claims 1 to 12, having a density measured according to ISO 845 in the range of

14. One or both of the following properties i) a melt strength F in the range of at most 20.0 cN, preferably 5.0 to 20.0 cN ３０ (ISO 16790:2005), ii) A shear viscosity reduction index SHI determined as described in the specification, which is at most 40.0, preferably in the range of 10.0 to 35.0, more preferably in the range of 10.0 to 30.0 （０．０５／３００） The foam according to any one of claims 1 to 13, having one or both of them.

15. One or more of the following properties i) A closed cell content measured according to ASTM D6226 of up to 50%, preferably in the range of 5 to 45%, ii) An elongation at break measured in the longitudinal direction (MD) according to ISO1798 of at least 10%, preferably in the range of 10 to 20%, and iii) A tensile strength measured in the longitudinal direction (MD) according to ISO1798 of at least 1050 kPa, preferably in the range of 1050 to 2000 kPa The foam according to any one of claims 1 to 14, having two or more, more preferably all of them.

16. A method for preparing the foam according to any one of claims 1 to 15, comprising: a) A step of providing a polypropylene composition, wherein the polypropylene composition comprises: (a) Long-chain branched polypropylene, (b)A melt flow rate MFR of at least 15.0 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C), and linear polypropylene present in the polypropylene composition in an amount of at least 30.0% by weight based on the total weight of the polypropylene composition Including the step of, b) A step of foaming the polypropylene composition provided in step a) to obtain a foam Including the method.

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