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) at least 40.0% by weight of long-chain branched polypropylene and (b) at least 20.0% by weight of linear polypropylene, and the amounts by weight are based on the total weight of this polypropylene composition. This polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 2.5 g / 10 min. Furthermore, a foam containing this polypropylene composition, as well as a process for preparing the polypropylene composition and the foam, are provided.

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 the polypropylene composition and a process for preparing the material. The present application also relates to the behavior of the polypropylene composition under shear exposure in a melt extrusion process.

Background Art

[0002] Long-chain branched polypropylenes are known for their high melt strength, and for this reason these materials are particularly useful for various applications such as foaming applications.

[0003] It is known that long-chain branched polypropylenes and other polypropylenes having high melt strength can deteriorate when subjected to certain processing conditions such as melt processing in an extruder. A significant decrease in melt strength and / or melt drawability is typically observed after processing of long-chain branched polypropylenes. This is related to the shear exposure of long-chain branched polypropylenes during the extrusion process. The decrease in melt strength adversely affects the foamability of long-chain branched polypropylenes or high melt strength polypropylene compositions containing them after extrusion foaming. When the melt strength of the processed polypropylene composition drops below a certain value due to degradation under shear, the composition may no longer be suitable for fulfilling its original purpose such as being foamable.

[0004] The loss of melt strength ultimately limits the reusability of used or recycled long-chain branched polypropylenes or polypropylene compositions containing them in the foaming process. For example, it is a common problem to add more than about 10 wt% of high melt strength polypropylene recyclate to produce a low density extrusion foam without loss of foaming efficiency (increase in density).

[0005] Several options are known for reducing the loss of melt strength during processing of high melt strength polymer compositions. For example, it is possible to reduce the shear exposure of the polymer during extrusion by reducing the output of the extruder and / or by increasing the size of the extruder while maintaining the same output level. However, both approaches are costly and often not economically feasible.

[0006] An alternative approach is to modify the polymer composition used in the extrusion foaming process, i.e., to modify the polymer composition so that it has lower shear sensitivity, enabling better foaming and better quality of recycled materials.

[0007] WO 2017 / 068106 A1 relates to a long-chain branched polypropylene composition comprising a long-chain branched propylene homopolymer or a long-chain branched propylene copolymer and a linear propylene homopolymer or a linear propylene copolymer. This long-chain branched polypropylene composition is suitable for foam applications. The linear propylene homopolymer or the linear propylene copolymer has a particularly low melt flow rate. Blending a low melt flow rate linear polypropylene with a high long-chain branched polypropylene typically further reduces the low melt flow rate of the long-chain branched polypropylene, which can have an adverse effect on processability.

[0008] There continues to be a need in the art for polypropylene compositions that are suitable for foaming and have lower shear sensitivity than comparable materials. It is further desirable for such polypropylene compositions to have a relatively high melt flow rate in order to provide good processability, for example, in the manufacture of low density foams.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0009]

PATENT DOCUMENT 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a polypropylene composition for preparing a foam, a foam containing the same, and a process for preparing the above materials.

Means for Solving the Problems

[0011] One aspect of the present invention provides a polypropylene composition for preparing a foam. This polypropylene composition (a) at least 40.0% by weight of long-chain branched polypropylene, and (b) at least 20.0% by weight of linear polypropylene and. The amounts by weight of the long-chain branched polypropylene (a) and the linear polypropylene (b) are based on the total weight of the polypropylene composition. Further, the polypropylene composition is required to have a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 ° C) of at least 2.5 g / 10 min.

[0012] One finding of the present inventors is that the polypropylene composition provided herein has lower shear sensitivity and better processability than comparable polypropylene compositions for preparing foams, particularly low-density foams. The reduction in shear sensitivity can be indicated by an increase in the melt strength stability of the polypropylene composition during extrusion processing. The reduction in shear sensitivity and / or reduction in degradation during processing can improve the recyclability of the polypropylene composition. This is because this material has less tendency to lose its functionality due to continuous degradation during its reuse. The polypropylene composition was further found to be suitable for preparing foams, particularly low-density foams. This polypropylene composition can be foamed to a low density using a standard commercial foaming process.

[0013] According to one preferred embodiment of the present invention, a polypropylene composition for preparing a foam is provided, and this polypropylene composition comprises (a) at least 40.0% by weight of long-chain branched polypropylene, and (b) at least 30.0% by weight of linear polypropylene and the amounts by weight are based on the total weight of the polypropylene composition, this polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min.

[0014] Another aspect of the present invention provides a foam. This foam comprises a polypropylene composition according to one embodiment of the present invention.

[0015] Another aspect of the present invention provides a process for preparing a polypropylene composition according to one embodiment of the present invention or a foam according to one embodiment of the present invention. This process comprises a) providing a mixture comprising · a long-chain branched polypropylene starting material, · a linear polypropylene starting material, and · optionally, one or more additives b) melt-blending the mixture provided in step a) to obtain a polypropylene composition, and c) optionally, foaming the melt-blended mixture provided in step b) to obtain a foam and comprises.

[0016] 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.

[0017] Further embodiments of the present invention are defined in the dependent claims.

[0018] According to one embodiment of the present invention, the polypropylene composition (a) 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of long-chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 are by weight based on the total weight of the polypropylene composition, and optionally, components (a) to (c) together are 100% by weight.

[0019] According to one embodiment of the present invention, the polypropylene composition has the following properties i) A melt strength F of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, even more preferably in the range of 5.0 to 23.0 cN 30 (ISO 16790:2005), ii) A melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, preferably in the range of 3.0 to 20.0 g / 10 min, and iii) A melt drawability v in the range of 180 to 320 mm / s, preferably in the range of 200 to 280 mm / s, more preferably in the range of 220 to 260 mm / s 30 (ISO 16790:2005) has one or more, preferably two or more, more preferably all of them.

[0020] According to one embodiment of the present invention, the polypropylene composition has a shear thinning index SHI determined as described herein in the range of less than 40.0, preferably in the range of 10.0 to less than 40.0. (0.05 / 300) has.

[0021] According to one embodiment of the present invention, the long-chain branched polypropylene is a long-chain branched propylene homopolymer.

[0022] According to one embodiment of the present invention, the long-chain branched polypropylene is preferably derived from a long-chain branched polypropylene starting material obtained by treating linear polypropylene with a radical former in the presence of a difunctional unsaturated monomer(s) and / or a polyfunctional unsaturated low molecular weight polymer(s).

[0023] According to one embodiment of the present invention, the linear polypropylene is a linear propylene homopolymer.

[0024] According to one embodiment of the present invention, the polypropylene composition contains one or more additives, and the one or more additives include a nucleating agent, preferably talc as the nucleating agent.

[0025] 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 25.0 to 45.0 cN, more preferably 30.0 to 40.0 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 30 (ISO16790:2005), iii) A melt flow rate MFR2 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 (ISO1133, 2.16 kg load, 230 °C) derived from a long-chain branched polypropylene starting material having one or more, preferably two or more, more preferably all of the above.

[0026] According to one embodiment of the present invention, the above linear polypropylene has the following properties i) A melt strength F of at most 15.0 cN, preferably at most 10.0 cN, more preferably at most 8.0 cN 30 (ISO 16790:2005), ii) A melt drawability v of at most 210 mm / s, preferably at most 200 mm / s, more preferably at most 190 mm / s 30 (ISO 16790:2005), iii) A melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.0 to 50.0 g / 10 min, preferably 2.5 to 40.0 g / 10 min, more preferably 2.8 to 30.0 g / 10 min and is derived from a linear polypropylene starting material having one or more, preferably two or more, more preferably all of the above properties.

[0027] According to one embodiment of the present invention, the polypropylene composition can be obtained using, or is obtained from, a mixture, preferably a dry blend, comprising a long-chain branched polypropylene starting material and a linear polypropylene starting material. The linear polypropylene starting material has the following properties i) A melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) higher than that of the above long-chain branched polypropylene starting material, and ii) A melt strength F lower than that of the above long-chain branched polypropylene starting material 30 (ISO 16790:2005) 30 (ISO 16790:2005) and has.

[0028] According to one embodiment of the present invention, the foam has a density of 3 at most 100 kg / m 3 and preferably in the range of 20 to 100 kg / m.

[0029] According to one embodiment of the present invention, the foam has the following properties i) A melt strength F of at most 23.0 cN, preferably in the range of 5.0 to 23.0 cN30 (ISO16790:2005), (ii) a shear thinning index SHI as determined as described herein, less than 40.0, preferably in the range of from 10.0 to less than 40.0 (0.05 / 300) having one or both of the above.

[0030] When the term "comprising" is used in this specification and the 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.

[0031] The present invention will now be described in more detail.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Polypropylene composition for preparing a foam One aspect of the present invention provides a polypropylene composition for preparing a foam. This polypropylene composition comprises (a) at least 40.0% by weight of a long chain branched polypropylene, and (b) at least 20.0% by weight of a linear (unbranched) polypropylene and. The amounts by weight of the long-chain branched polypropylene (a) and the linear polypropylene (b) are based on the total weight of the polypropylene composition. The polypropylene composition is further required to have a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 2.5 g / 10 min.

[0033] According to one preferred embodiment of the present invention, there is provided a polypropylene composition for preparing a foam, and this polypropylene composition (a) at least 40.0% by weight of long-chain branched polypropylene; and (b) at least 30.0% by weight of linear polypropylene wherein the amounts by weight are based on the total weight of the polypropylene composition, and this polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min.

[0034] The polypropylene composition provided herein is suitable for preparing a foam. "Suitable for preparing a foam" includes, for example, a polypropylene composition that can be foamed by using a physical blowing agent provided externally in an extrusion foaming process. Therefore, "suitable for preparing a foam" should be understood in the sense that the polypropylene composition does not necessarily contain a blowing agent (however, this is possible).

[0035] According to one preferred embodiment, the polypropylene composition is suitable for preparing a foam by an extrusion foaming process using a physical blowing agent (for example, a gas such as butane).

[0036] However, this should not be understood to mean that the polypropylene composition is only suitable for preparing a foam. Other uses and applications of the polypropylene composition provided herein are possible and not excluded.

[0037] 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)".

[0038] 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 that 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 branches 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.

[0039] Due to specific melt strength characteristics, long-chain branched polypropylene is also referred to as high melt strength polypropylene in the art.

[0040] 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 may be made to European Patent Application Publication No. 1892264. For long-chain branched polypropylene obtained by chemical modification, for example, European Patent Application Publication No. 0787750, European Patent Application Publication No. 0879830A1, and European Patent Application Publication No. 0890612A2 may be referred to.

[0041] Long-chain branched polypropylene typically has a relatively low melt flow rate in combination with high melt strength and high melt extensibility.

[0042] The polypropylene composition contains at least one kind of long-chain branched polypropylene (a), for example, 1 to 3 kinds of long-chain branched polypropylene (a). For example, the polypropylene composition can contain one kind of long-chain branched polypropylene (a).

[0043] The long-chain branched polypropylene (a) is not particularly limited as long as it is suitable for preparing the polypropylene composition according to one embodiment of the present invention.

[0044] 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.

[0045] 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 is 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 C2-C3 copolymer.

[0046] The comonomer content of the long-chain branched propylene copolymer 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%.

[0047] 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.

[0048] 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 difunctional unsaturated monomer (s) and / or a polyfunctional unsaturated low molecular weight polymer (s) in reactive extrusion.

[0049] The polypropylene composition contains at least 40.0% by weight of long-chain branched polypropylene (a) based on the total weight of the polypropylene composition. Preferably, the polypropylene composition contains at least 50.0% by weight, more preferably at least 55.0% by weight, and even more preferably at least 57.5% by weight of long-chain branched polypropylene based on the total weight of the polypropylene composition.

[0050] The polypropylene composition preferably contains 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, and even more preferably 57.5 to 62.5% by weight of long-chain branched polypropylene (a) based on the total weight of the polypropylene composition.

[0051] The long-chain branched polypropylene (a) present in the polypropylene composition of the present invention is preferably derived from a specific long-chain branched polypropylene starting material, i.e., the material used to prepare the polypropylene composition of the present invention.

[0052] The long-chain branched polypropylene starting material preferably has specific properties such as specific melt characteristics.

[0053] The long-chain branched polypropylene starting material 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).

[0054] The long-chain branched polypropylene starting material 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).

[0055] The long-chain branched polypropylene starting material 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.

[0056] According to one preferred embodiment, the long-chain branched polypropylene starting material 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 in the range of 210 to 300 mm / s, more preferably in the range of 230 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 having two or more, more preferably all, of the above.

[0057] The long-chain branched polypropylene starting material 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.

[0058] The long-chain branched polypropylene starting material 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).

[0059] The radical-forming agent 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 with 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 Nos. 0787750 A2, 0879830 A1, and 0890612 A2.

[0060] A suitable long-chain branched polypropylene starting material is WB140HMS (trademark), commercially available from Borealis AG.

[0061] 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)".

[0062] 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 determining the branching index using gel phase chromatography (GPC). 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.

[0063] The polypropylene composition contains at least one kind of linear polypropylene (b), for example, 1 to 3 kinds of linear polypropylene (b).

[0064] Linear polypropylene (b) is not particularly limited in principle as long as it is suitable for preparing the polypropylene composition according to the present invention. Linear polypropylene (b) is not particularly limited in terms of chemical composition. Linear polypropylene (b) may be a propylene copolymer or a propylene homopolymer.

[0065] The linear polypropylene (b) may be a propylene copolymer, such as a propylene random copolymer. When the linear polypropylene (b) is a propylene copolymer, the linear polypropylene (b) may contain a comonomer selected from the group consisting of ethylene and / or 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.

[0066] 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%.

[0067] It is preferable that the linear polypropylene (b) is a linear propylene homopolymer. Therefore, according to one preferred embodiment of the present invention, the linear polypropylene (b) is a linear propylene homopolymer.

[0068] According to one more preferred embodiment, the long-chain branched polypropylene (a) and the linear polypropylene (b) are propylene homopolymers.

[0069] The polypropylene composition contains at least 20.0% by weight of the linear polypropylene (b) 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, even more preferably at least 37.5% by weight of the linear polypropylene (b) based on the total weight of the polypropylene composition.

[0070] More preferably, the polypropylene composition contains 20.0 to 60.0% by weight, more preferably 30.0 to 50.0% by weight, even more preferably 35.0 to 45.0% by weight, still even more preferably 37.5 to 42.5% by weight of the linear polypropylene (b) based on the total weight of the polypropylene composition.

[0071] The linear polypropylene (b) present in the polypropylene composition of the present invention is preferably derived from a specific linear polypropylene starting material, i.e., the material used to prepare the polypropylene composition of the present invention.

[0072] The linear polypropylene starting material preferably has a melt strength F of at most 15.0 cN (e.g., in the range of 0.1 to 15.0 cN), preferably at most 10.0 cN (e.g., in the range of 0.1 to 10.0 cN), more preferably at most 8.0 cN, such as in the range of 0.1 to 8.0 cN or 0.5 to 8.0 cN. 30 (ISO 16790:2005).

[0073] The linear polypropylene starting material preferably has a melt drawability v of at most 210 mm / s (e.g., in the range of 130 mm / s to 210 mm / s), preferably at most 200 mm / s (e.g., in the range of 130 mm / s to 200 mm / s), more preferably at most 190 mm / s, and most preferably in the range of 140 to 190 mm / s. 30 (ISO 16790:2005).

[0074] The linear polypropylene starting material preferably has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.0 to 50.0 g / 10 min, preferably 2.5 to 40.0 g / 10 min, more preferably 2.8 to 30.0 g / 10 min.

[0075] According to one preferred embodiment, the linear polypropylene starting material has the following properties i) a melt strength F of at most 15.0 cN (e.g., in the range of 0.1 to 15.0 cN), preferably at most 10.0 cN (e.g., in the range of 0.1 to 10.0 cN), more preferably at most 8.0 cN, such as in the range of 0.1 to 8.0 cN, or 1.0 to 8.0 cN 30 (ISO 16790:2005), ii) A melt drawability v of up to 210 mm / s (e.g., in the range of 100 mm / s to 210 mm / s), preferably up to 200 mm / s (e.g., in the range of 100 mm / s to 200 mm / s), more preferably up to 190 mm / s, e.g., in the range of 100 mm / s to 190 mm / s, or in the range of 140 to 190 mm / s 30 (ISO16790:2005), iii) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.0 to 50.0 g / 10 min, preferably 2.5 to 40.0 g / 10 min, more preferably 2.8 to 30.0 g / 10 min having two or more of them, more preferably all of them.

[0076] According to one more preferred embodiment, the linear polypropylene starting material has the following properties i) A melt strength F of up to 5.0 cN (e.g., in the range of 0.1 to 5.0 cN), preferably up to 3.0 cN (e.g., in the range of 0.1 to 3.0 cN), more preferably up to 2.5 cN, e.g., in the range of 0.1 to 2.5 cN, or in the range of 0.5 to 2.5 cN 30 (ISO16790:2005), ii) A melt drawability v of up to 210 mm / s (e.g., in the range of 130 mm / s to 210 mm / s), preferably up to 200 mm / s (e.g., in the range of 130 mm / s to 200 mm / s), more preferably up to 190 mm / s, most preferably in the range of 140 to 190 mm / s 30 (ISO16790:2005), iii) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.0 to 35.0 g / 10 min, preferably 5.0 to 20.0 g / 10 min, more preferably in the range of 7.5 to 18.0 g / 10 min, e.g., in the range of 10.0 to 15.0 g / 10 min having one or more of them, even more preferably two, and still even more preferably all of them.

[0077] An example of a suitable linear polypropylene starting material is the commercially available polypropylenes HE125MO, HC600TF, and HG313MO from Borealis AG.

[0078] Additive (c) The polypropylene composition may optionally 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.

[0079] The additives may vary depending on the use of the polypropylene composition, the equipment for processing the polypropylene composition, and / or the product containing the polypropylene composition, preferably the use of the foam. The additives can be selected by those skilled in the art.

[0080] The polypropylene composition can contain one or more additional polymer components as additive (c) or as part of additive (c). These 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).

[0081] For example, the additional polymer component may be a polymer material originally introduced into the polypropylene composition as part of an additive masterbatch, that is, as a polymer carrier material. However, it is also possible to select the polymer carrier material of the additive masterbatch to be very similar to or essentially the same as, for example, the linear polypropylene (b).

[0082] For example, the polypropylene composition may be prepared using an additive masterbatch containing a nucleating agent and a polymer carrier resin, for example, a polypropylene carrier resin. The polymer carrier resin may be the same as or different from the remaining polymer components (a) or (b).

[0083] The polypropylene composition preferably contains a nucleating agent such as talc. According to one preferred embodiment, the polypropylene composition contains one or more additives as component (c), and the one or more additives include a nucleating agent. Preferably, the nucleating agent is talc.

[0084] 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.

[0085] The polypropylene composition preferably contains 0.01 to 5.0% by weight, more preferably 0.1 to 4.0% by weight, still 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.

[0086] 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, still 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 the one or more additives (c) include a nucleating agent, that is, the nucleating agent is part of the one or more additives (c) or is the one additive (c). This nucleating agent is preferably talc.

[0087] The 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% to 100% by weight based on the total weight of the one or more additives (c). The remaining portion of the one or more additives (c) may be a polymer carrier resin, such as polypropylene suitable for use in a polymer masterbatch, but is not limited thereto.

[0088] 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, based on the total weight of the polypropylene composition, of a nucleating agent, preferably talc.

[0089] Polypropylene composition One requirement is that the polypropylene composition of the present invention has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 2.5 g / 10 min.

[0090] Preferably, the polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, more preferably in the range of 3.0 to 20.0 g / 10 min, for example in the range of 3.0 to 16.0 g / 10 min.

[0091] The polypropylene composition can have further properties that make it particularly useful for foaming applications.

[0092] The polypropylene composition preferably has a melt strength F in the range of at least 5.0 cN, more preferably in the range of 5.0 to 30.0 cN, even more preferably in the range of 5.0 to 27.5 cN, still even more preferably in the range of 5.0 to 23.0 cN, for example in the range of 5.0 to a maximum of 20.0 cN 30 (ISO 16790:2005).

[0093] The polypropylene composition can have a melt drawability v in the range of 180 to 320 mm / s, preferably 200 to 280 mm / s, more preferably 220 to 260 mm / s 30 (ISO 16790:2005).

[0094] According to one preferred embodiment of the present invention, the polypropylene composition has the following properties i) A melt strength F in the range of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, even more preferably in the range of 5.0 to 23.0 cN, for example in the range of 5.0 to a maximum of 20.0 cN 30 (ISO16790:2005), ii) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, preferably in the range of 3.0 to 20.0 g / 10 min, for example in the range of 3.0 to 16.0 g / 10 min iii) A melt drawability v in the range of 180 to 320 mm / s, preferably in the range of 200 to 280 mm / s, more preferably in the range of 220 to 260 mm / s 30 (ISO16790:2005) having two or more, preferably all, of the above.

[0095] The polypropylene composition preferably features a relatively low shear thinning index. As is known in the art, shear thinning is the non-Newtonian behavior of a fluid where the viscosity decreases under shear strain. The polypropylene composition of the present invention can exhibit lower shear thinning than comparable foaming polypropylene compositions.

[0096] Preferably, the polypropylene composition has a shear thinning index SHI determined as described herein in the "Method" section that is less than 40.0, preferably in the range of 10.0 to less than 40.0. (0.05 / 300) having.

[0097] The polypropylene composition preferably has a maximum of 8.0 Pa -1 , preferably in the range of 2.5 to 8.0 Pa -1 and more preferably in the range of 3.0 to 7.0 Pa -1 having a polydispersity index (PI) determined as described herein in the "Method" section.

[0098] According to yet another more preferred embodiment, the polypropylene composition has the following properties i) a melt strength F in the range of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, even more preferably in the range of 5.0 to 23.0 cN, for example in the range of 5.0 to at most 20.0 cN 30 (ISO16790:2005), ii) a melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, preferably in the range of 3.0 to 20.0 g / 10 min, for example in the range of 3.0 to 16.0 g / 10 min iii) a melt drawability v in the range of 180 to 320 mm / s, preferably in the range of 200 to 280 mm / s, more preferably in the range of 220 to 260 mm / s 30 (ISO16790:2005), and iv) a shear thinning index SHI determined as described herein in the section "Method" of less than 40.0, preferably in the range of 10.0 to less than 40.0 (0.05 / 300) and having all of the above.

[0099] According to another more preferred embodiment, the polypropylene composition has the following properties i) a melt strength F in the range of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, even more preferably in the range of 5.0 to 23.0 cN, for example in the range of 5.0 to at most 20.0 cN 30 (ISO16790:2005), ii) a melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, preferably in the range of 3.0 to 20.0 g / 10 min, for example in the range of 3.0 to 16.0 g / 10 min iii) a melt drawability v in the range of 180 to 320 mm / s, preferably in the range of 200 to 280 mm / s, more preferably in the range of 220 to 260 mm / s 30 (ISO16790:2005), and iv) at most 8.0 Pa -1, preferably in the range of 2.5 to 8.0 Pa -1 in the range of, more preferably in the range of 3.0 to 7.0 Pa -1 The polydispersity index (PI) determined as described herein in the "Method" section, having all of all of them.

[0100] In one more specific embodiment, the polypropylene composition has the following properties i) a melt strength F in the range of at least 5.0 cN, for example in the range of 5.0 to 10.0 cN 30 (ISO 16790:2005), ii) a melt flow rate MFR2 in the range of 5.0 to 20.0 g / 10 min, for example in the range of 5.0 to 15.0 g / 10 min (ISO 1133, 2.16 kg load, 230 °C), iii) a melt drawability v in the range of 200 to 280 mm / s, for example in the range of 220 to 260 mm / s 30 (ISO 16790:2005), and iv) a shear thinning index SHI determined as described herein in the "Method" section, up to 30.0, for example in the range of 15.0 to 30.0 (0.05 / 300) having all of them.

[0101] According to one more specific embodiment, the polypropylene composition has the following properties i) a melt strength F in the range of 5.0 to 10.0 cN 30 (ISO 16790:2005), ii) a melt flow rate MFR2 in the range of 5.0 to 12.0 g / 10 min (ISO 1133, 2.16 kg load, 230 °C), iii) a melt drawability v in the range of 220 to 260 mm / s 30 (ISO 16790:2005), and iv) a shear thinning index SHI determined as described herein in the "Method" section, in the range of 20.0 to 30.0 (0.05 / 300) having all of them.

[0102] Typically, the polypropylene composition contains components (a) and (b), and optionally component (c) in amounts based on specific weights.

[0103] Preferably, the polypropylene composition (a) 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, and even more preferably 57.5 to 62.5% by weight of long-chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, and even more preferably 37.5 to 42.5% by weight of linear polypropylene and the amounts by weight are based on the total weight of the polypropylene composition.

[0104] In addition to components (a) and (b), the polypropylene composition can further contain other components, such as other polymer blend partners.

[0105] 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.

[0106] It is also possible for the polypropylene composition to essentially contain no polymer material different from at least one long-chain branched polypropylene (a) and at least one linear polypropylene (b).

[0107] The polypropylene composition preferably contains one or more of the additives (c) described above herein. According to one preferred embodiment, the polypropylene composition (a) 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of long chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 the amounts by weight are based on the total weight of the polypropylene composition.

[0108] According to one preferred embodiment, the polypropylene composition (a) 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of long chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 the amounts by weight are based on the total weight of the polypropylene composition, and components (a) to (c) together amount to 100% by weight.

[0109] According to one preferred embodiment, the polypropylene composition (a) 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of long chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 the amounts by all weights are based on the total weight of the polypropylene composition.

[0110] According to one preferred embodiment, the polypropylene composition (a) 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of long chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 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.

[0111] According to one preferred embodiment, the polypropylene composition (a) 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of long chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% 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 consisting essentially of, or consisting of, these, and all amounts by weight are based on the total weight of the polypropylene composition.

[0112] According to one preferred embodiment, the polypropylene composition (a) 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of long-chain branched polypropylene, (b) 20.0 to 59.99% by weight, preferably 30.0 to 49.9% by weight, more preferably 35.0 to 44.8% by weight, even more preferably 37.5 to 42.3% 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 consisting essentially of, or consisting of, these, and all amounts by weight are based on the total weight of the polypropylene composition.

[0113] Preferably, the one or more additives include a nucleating agent, and more preferably include talc as the nucleating agent. The one or more additives can include additional polymer materials such as additional polypropylene.

[0114] The polypropylene composition can preferably be obtained, or is obtained, using a mixture of specific starting materials. Preferably, the polypropylene composition can preferably be obtained, or is obtained, by melt blending a dry blend of specific starting materials.

[0115] According to one preferred embodiment of the present invention, the polypropylene composition can be obtained using, or is obtained using, a mixture, preferably a dry blend, comprising a long-chain branched polypropylene starting material and a linear polypropylene starting material. The linear polypropylene starting material has the following properties i) A melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) higher than that of the long-chain branched polypropylene starting material, and ii) A melt strength F 30 (ISO 16790:2005) lower than that of the long-chain branched polypropylene starting material 30 (ISO 16790:2005) having.

[0116] The polypropylene composition preferably comprises · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of the long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of the linear polypropylene starting material and can be obtained using, or is obtained using, a mixture, preferably a dry blend, the amounts by weight being based on the total weight of the mixture, preferably the dry blend.

[0117] Regarding the long-chain branched polypropylene starting material and the linear polypropylene starting material present in the above mixture, the embodiments and preferred embodiments of the long-chain branched polypropylene starting material and the linear polypropylene starting material described hereinabove are referred to at the places of "long-chain branched polypropylene (a)" and "linear polypropylene (b)", respectively.

[0118] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 the amounts by weight are based on the total weight of the mixture, preferably the dry blend.

[0119] Regarding the one or more additives present in the above mixture, the embodiments and preferred embodiments of the one or more additives described hereinabove in the section "Additive (c)" are referred to.

[0120] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 the amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together amount to 100% by weight.

[0121] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 are included, and the amounts by weight are based on the total weight of the mixture, preferably the dry blend.

[0122] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 are included, and the amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together amount to 100% by weight.

[0123] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene, and · 20.0 to 60.0 wt%, preferably 30.0 to 50.0 wt%, more preferably 35.0 to 45.0 wt%, even more preferably 37.5 to 42.5 wt% of linear polypropylene, and · 0.01 to 5.0 wt%, preferably 0.1 to 4.0 wt%, more preferably 0.2 to 3.0 wt%, even more preferably 0.2 to 2.0 wt% of one or more additives consisting essentially of or consisting of these, and all amounts by weight are based on the total weight of the polypropylene composition.

[0124] The above one or more additives are preferably present in the form of a mixture, preferably a dry blend, of a masterbatch. The additive masterbatch preferably contains a polymer carrier resin, more preferably polypropylene, and a nucleating agent, more preferably talc.

[0125] Accordingly, according to one preferred embodiment, the above mixture, preferably the dry blend, is · 40.0 to 79.99 wt%, preferably 50.0 to 69.9 wt%, more preferably 55.0 to 64.8 wt%, even more preferably 57.5 to 62.48 wt% of a long-chain branched polypropylene starting material, and · 20.0 to 60.0 wt%, preferably 30.0 to 50.0 wt%, more preferably 35.0 to 45.0 wt%, even more preferably 37.5 to 42.5 wt% of a linear polypropylene starting material, and · 0.01 to 5.0 wt%, preferably 0.1 to 4.0 wt%, more preferably 0.2 to 3.0 wt%, even more preferably 0.2 to 2.0 wt% of an additive present in the form of a masterbatch and containing a nucleating agent (such as talc) and a polymer carrier resin (such as polypropylene), and the amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together total 100 wt%.

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

[0127] Preferably, the foam contains 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. This foam preferably consists essentially of or consists of a polypropylene composition according to one embodiment of the present invention.

[0128] The above polypropylene composition is further defined by one or more embodiments of the polypropylene composition described herein in the section "Polypropylene Composition for Preparing Foam" including the section "Polypropylene Composition" and described 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)".

[0129] The foam preferably has a low density. According to one preferred embodiment, the foam has a density in the range of 100 kg / m 3 or less, more preferably in the range of 20 to 100 kg / m 3 Optionally in the range of 20 to 80 kg / m 3 For example, in the range of 40 to 80 kg / m 3

[0130] The foam is preferably a foamed sheet. The foamed sheet can have a thickness in the range of 10.0 mm or less, preferably in the range of 0.5 to 10.0 mm, for example, in the range of 0.5 to 7.0 mm.

[0131] According to one preferred embodiment, the foam has a thickness in the range of 10.0 mm or less, preferably in the range of 0.5 to 10.0 mm, and a density of 100 kg / m 3 or less, more preferably in the range of 20 to 100 kg / m​3 in the range of, optionally 20 - 80 kg / m 3 in the range of, for example 40 - 80 kg / m 3 and is a foamed sheet having a density in the range of.

[0132] The foam can have specific properties such as melt strength and shear thinning index.

[0133] Preferably, the foam has a melt strength F of at most 23.0 cN, more preferably in the range of 5.0 - 23.0 cN, for example in the range of 5.0 - 20.0 30 (ISO16790:2005).

[0134] The foam has a shear thinning index SHI as determined as described herein, less than 40.0, preferably in the range of 10.0 - less than 40.0 (0.05 / 300) and preferably has.

[0135] According to one preferred embodiment of the present invention, the foam has the following properties i) a melt strength F of at most 23.0 cN, preferably in the range of 5.0 - 23.0 cN, for example in the range of 5.0 - 20.0 30 (ISO16790:2005), and ii) a shear thinning index SHI as determined as described herein, less than 40.0, preferably in the range of 10.0 - less than 40.0 (0.05 / 300) and has both.

[0136] A process for preparing a polypropylene composition or a foam containing the same In another aspect, the present invention provides a process (method) for preparing a polypropylene composition according to one embodiment of the present invention or a foam according to one embodiment of the present invention.

[0137] The process is preferably a melt extrusion process and / or an extrusion foaming process. Such processes are known in the art.

[0138] The process is preferably an extrusion foaming process using a tandem foam extrusion line. This equipment is known in the art. A tandem extrusion line typically includes a co-rotating twin screw extruder for compounding and incorporating a foaming agent, and a single screw extruder for cooling the foamed melt.

[0139] This process comprises a) providing a mixture comprising · a long chain branched polypropylene starting material, · a linear polypropylene starting material, and · optionally, one or more additives b) melt blending the mixture provided in step a) to obtain the polypropylene composition described herein, and c) optionally, foaming the polypropylene composition provided in step b) to obtain the foam described herein. The mixture provided in step a) may be present in any form suitable for melt blending in an extruder. The mixture provided in step a) is preferably a dry blend. The dry blend can be prepared by any means known in the art.

[0140] With respect to the long chain branched polypropylene starting material and the linear polypropylene starting material present in the mixture provided in step a), the embodiments and preferred embodiments of the long chain branched polypropylene starting material and the linear polypropylene starting material described herein are referred to at the places of "long chain branched polypropylene (a)" and "linear polypropylene (b)", respectively.

[0141]

[0142] The one or more additives may be present as a single component or in the form of an additive masterbatch. Additive masterbatches are known in the art.

[0143] ​The above one or more additives preferably exist in the form of an additive masterbatch. This additive masterbatch can contain a polymer carrier resin and a nucleating agent. The polymer carrier resin is preferably polypropylene, which optionally has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) in the range of 0.5 to 10.0 g / min, for example in the range of 1.0 to 6.0 g / 10 min. The nucleating agent is preferably talc.

[0144] The mixture provided in step a), preferably the dry blend, typically contains the above materials in amounts by specific weight.

[0145] The above mixture, preferably the dry blend, · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material and can include, and the amounts by weight are based on the total weight of the mixture, preferably the dry blend.

[0146] The above polypropylene composition preferably contains one or more additives. According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 The amounts by weight are based on the total weight of the mixture, preferably the dry blend.

[0147] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 The amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together amount to 100% by weight.

[0148] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 The amounts by weight are based on the total weight of the mixture, preferably the dry blend.

[0149] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 are included, and the amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together amount to 100% by weight.

[0150] According to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of long-chain branched polypropylene, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of linear polypropylene, and · 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 consists essentially of or consists of these, and all amounts by weight are based on the total weight of the polypropylene composition.

[0151] The above one or more additives are preferably present in the mixture in the form of a masterbatch. This additive masterbatch preferably contains a polymer carrier resin, more preferably polypropylene, and a nucleating agent, more preferably talc.

[0152] Accordingly, according to one preferred embodiment, the above mixture, preferably the dry blend, · 40.0 to 79.99% by weight, preferably 50.0 to 69.9% by weight, more preferably 55.0 to 64.8% by weight, even more preferably 57.5 to 62.48% by weight of a long-chain branched polypropylene starting material, and · 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of a linear polypropylene starting material, and · 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 present in the form of a masterbatch, the additive containing a nucleating agent (e.g., talc) and a polymer support resin (e.g., polypropylene) and the amounts by weight are based on the total weight of the mixture, preferably the dry blend, and the above components together amount to 100% by weight.

[0153] In step b), the mixture provided in step a) is melt blended to obtain the polypropylene composition described herein. The melt blending step can be carried out by any suitable means known in the art, preferably in an extruder. Those skilled in the art can select an appropriate extruder.

[0154] If the optional foaming step c) is not carried out, the polypropylene composition can be obtained in the form of a melt compounded polypropylene composition and can preferably be extrusion molded.

[0155] However, the process preferably includes step c) of foaming the polypropylene composition provided in step b) to obtain the foam described herein.

[0156] Step c) is preferably carried out using a physical blowing agent in an extrusion foaming process. The physical blowing agent is typically a gas such as butane.

[0157] Use Another aspect of the present invention provides the use of the polypropylene composition described herein for preparing a foam.

[0158] Regarding the polypropylene composition that can be used for preparing a foam and the possible and preferred embodiments of the foam that can be prepared, reference is made to the embodiments and preferred embodiments described above herein.

[0159] Without in any way limiting the foregoing disclosure, further aspects and embodiments of the present invention are defined in the following non-limiting items [1] to

[15] .

[0160] [1] A polypropylene composition for preparing a foam, wherein the polypropylene composition (a) at least 40.0% by weight of long-chain branched polypropylene, and (b) at least 20.0% by weight of linear polypropylene and the amounts by weight are based on the total weight of the polypropylene composition, the polypropylene composition has a melt flow rate MFR2 (ISO 1133, 2.16 kg load, 230 °C) of at least 2.5 g / 10 min.

[0161] [2] The polypropylene composition (a) 40.0 to 80.0% by weight, preferably 50.0 to 70.0% by weight, more preferably 55.0 to 65.0% by weight, even more preferably 57.5 to 62.5% by weight of the long-chain branched polypropylene, and (b) 20.0 to 60.0% by weight, preferably 30.0 to 50.0% by weight, more preferably 35.0 to 45.0% by weight, even more preferably 37.5 to 42.5% by weight of said 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 comprising, with all amounts by weight being based on the total weight of the polypropylene composition, and optionally, components (a) to (c) together amount to 100% by weight, the polypropylene composition according to item [1].

[0162] [3] The polypropylene composition has the following properties i) A melt strength F in the range of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, even more preferably in the range of 5.0 to 23.0 cN 30 (ISO16790:2005), ii) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.5 to 30.0 g / 10 min, preferably in the range of 3.0 to 20.0 g / 10 min, and iii) A melt drawability v in the range of 180 to 320 mm / s, preferably in the range of 200 to 280 mm / s, more preferably in the range of 220 to 260 mm / s 30 (ISO16790:2005) The polypropylene composition according to item [1] or item [2], having one or more, preferably two or more, more preferably all of the above.

[0163] [4] The polypropylene composition has a shear thinning index SHI as determined as described herein, less than 40.0, preferably in the range of 10.0 to less than 40.0 (0.05 / 300) The polypropylene composition according to any one of items [1] to [3].

[0164] [5] The polypropylene composition according to any one of items [1] to [4], wherein the long-chain branched polypropylene is a long-chain branched propylene homopolymer.

[0165] [6] The polypropylene composition according to any one of items [1] to [5], wherein the linear polypropylene is a linear propylene homopolymer.

[0166] [7] The polypropylene composition according to any one of items [1] to [6], wherein the polypropylene composition contains one or more additives, and the one or more additives include a nucleating agent, preferably talc as the nucleating agent.

[0167] [8] 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 25.0 to 45.0 cN, more preferably 30.0 to 40.0 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 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 1.0 to 3.0 g / 10 min, more preferably 1.2 to 2.5 g / 10 min The polypropylene composition according to any one of items [1] to [7], which is derived from a long-chain branched polypropylene starting material having one or more, preferably two or more, more preferably all of the above properties.

[0168] [9] The linear polypropylene has the following properties i) A melt strength F of at most 15.0 cN, preferably at most 10.0 cN, more preferably at most 8.0 cN 30 (ISO16790:2005), ii) A melt drawability v of up to 210 mm / s, preferably up to 200 mm / s, more preferably up to 190 mm / s 30 (ISO16790:2005), iii) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) in the range of 2.0 to 50.0 g / 10 min, preferably 2.5 to 40.0 g / 10 min, more preferably 2.8 to 30.0 g / 10 min The polypropylene composition according to any one of items [1] to [8], which is derived from a linear polypropylene starting material having one or more, preferably two or more, more preferably all of the above.

[0169]

[10] The polypropylene composition can be obtained by using, or is obtained from, a mixture, preferably a dry blend, comprising a long-chain branched polypropylene starting material and a linear polypropylene starting material. The linear polypropylene starting material has the following properties i) A melt flow rate MFR2 (ISO1133, 2.16 kg load, 230 °C) higher than that of the long-chain branched polypropylene starting material, and ii) A melt strength F lower than the melt strength F 30 (ISO16790:2005) of the long-chain branched polypropylene starting material 30 (ISO16790:2005) The polypropylene composition according to any one of items [1] to [9].

[0170]

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

[10] .

[0171]

[12] A foam according to item

[11] , having a density measured according to ISO845 of 100 kg / m 3 or less, preferably in the range of 20 to 100 kg / m 3 .

[0172]

[13] The following properties i) A melt strength F of up to 23.0 cN, preferably in the range of 5.0 to 23.0 cN 30 (ISO16790:2005), ii) A shear thinning index SHI determined as described herein of less than 40.0, preferably in the range of 10.0 to less than 40.0 (0.05 / 300) The foam according to item

[11] or

[12] , having one or both of the above.

[0173]

[14] A process for preparing the polypropylene composition according to any one of items [1] to

[10] or the foam according to any one of items

[11] to

[13] , a) providing a mixture comprising a long-chain branched polypropylene starting material, a linear polypropylene starting material, and optionally, one or more additives ; b) melt-blending the mixture provided in step a) to obtain a polypropylene composition; and c) optionally, foaming the melt-blended mixture provided in step b) to obtain a foam .

[0174]

[15] Use of the polypropylene composition according to any one of items [1] to

[10] for preparing a foam.

[0175] Hereinafter, the present invention will be described by way of specific examples, which should in no way be construed as limiting the present invention.

Examples

[0176] Method Melt flow rate (MFR): The melt flow rate MFR was determined according to ISO1133 at a temperature of 230 °C under a load of 2.16 kg.

[0177] Melt strength F30 and melt drawability v30: The tests described in this specification comply with ISO16790:2005. The tests were carried out at a pressure of 30 bar (bar).

[0178] 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, pp. 925-935. The content of this document is incorporated by reference. The strain hardening behavior of the polymer is analyzed by a Rheotens device (product of Goettfert, Siemensstr. 2, 74711 Buchen, Germany). In this device, the melt strand is stretched by pulling it down at a defined acceleration.

[0179] 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 pulled out. The stress applied to the extruded product is recorded as a function of the melt properties and the measurement parameters (especially the ratio of output to draw-off speed, which is 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 winding speed of the Rheotens wheel was adjusted to the speed of the extruded polymer strand (tensile force zero). Then, the experiment was started by slowly increasing the winding 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 pulled-down melt strand was 120 mm / s 2It is. This Rheotens was operated in combination with the PC program "EXTENS". This is a real-time data acquisition program that displays and stores measurement data of tensile force and draw-down speed. The end point of the Rheotens curve (force vs. pulley rotation speed) was taken as F 30 as the values of melt strength and extensibility.

[0180] Shear Thinning Index SHI (0.05 / 300) : The characterization of the melt of the polymer by dynamic shear measurement follows ISO standards 6721-1 and 6721-10. The measurements were carried out with 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 a compression-molded flat plate. 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.

[0181] In a dynamic shear experiment, the probe is subjected to uniform deformation with a sinusoidally varying shear strain or shear stress (modes of controlling strain and stress respectively). In a controlled strain experiment, the probe is subjected to a sinusoidal strain that can be expressed by the following equation. 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 equation. σ(t)=σ0sin(ωt+δ) (2) In the above equations, σ0 and γ0 are the stress amplitude and strain amplitude respectively, ω is the angular frequency, δ is the phase difference (loss angle between the applied strain and the stress response), and t is time.

[0182] Dynamic test results are typically represented by 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. The above rheological functions can be expressed as follows. [Number]

[0183] 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. [Number] For example, SHI (0.05 / 300) is defined as the value of the complex viscosity in Pa s determined for a value of G * equal to 0.05 kPa, divided by the value of the complex viscosity in Pa s determined for a value of G * equal to 300 kPa.

[0184] The values of the storage modulus (G’), loss modulus (G”), complex modulus (G * ) and complex viscosity (η * ) were obtained as functions of the frequency (ω).

[0185] 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.

[0186] 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.

[0187] The elasticity balance tan 0.05 / tan 300is defined as the ratio of loss tangent tan 0.05 to loss tangent tan 300 .

[0188] In addition to the above rheological functions, other rheological parameters such as the so-called elastic index EI(x) can also be determined. The elastic index EI(x) is the value of the storage modulus (G’) determined with respect to 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)

[0189] For example, EI(5 kPa) is defined by the value of the storage modulus (G’) determined with respect to the value of G” equal to 5 kPa.

[0190] 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., the higher the η 747 , the lower the sagging of the polyethylene composition.

[0191] The polydispersity index PI is defined by Equation 11. [Equation number] In the above equation, 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”.

[0192] The value is determined by a single-point interpolation procedure defined by Rheoplus software. In situations where the experimentally reachable 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.

[0193] 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.

[0194] Foam density: The foam density was measured in accordance with ISO845 using a semi - micro precision balance for analysis from PRECISA Gravimetrics AG, Switzerland.

[0195] Starting material 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. The properties of the material before and after compounding are shown in Table 1.

[0196] Linear polypropylene starting material (l - PP): Four different linear polypropylenes (l-PP) were used as starting materials. L-PP-1: A propylene homopolymer available as BE50 from Borealis AG L-PP-2: A propylene homopolymer available as HC600TF from Borealis AG L-PP-3: A propylene homopolymer available as HE125MO from Borealis AG L-PP-4: A propylene homopolymer available as HG313MO from Borealis AG

[0197] The properties of the materials before and after compounding are shown in Table 1.

[0198] Additive masterbatch (AM): A commercially available additive masterbatch (AM) was used. The additive masterbatch contains a nucleating agent which is about 70 wt% talc and about 30 wt% polypropylene. The polypropylene has a melt index (230 °C / 2.16 kg) of about 4 g / 10 min.

[0199] Examples 1) Melt-compounded polypropylene composition A melt-compounded blend containing 60 wt% long-chain branched polypropylene b-PP and 40 wt% linear polypropylene l-PP was prepared using a ZSK 32MC twin-screw extruder. To examine the effect of the processing steps on the properties of each component individually, the individual components were also exposed to the same compounding process as the blend being tested by using the same conditions as for blend preparation.

[0200] The properties of the individual components before and after compounding are shown in Table 1, and the properties of the melt-compounded blend are shown in Table 2.

[0201] [Table 1]

[0202] As can be seen from the data shown in Table 1, the incorporation of long-chain branched polypropylene b-PP has a negative impact on the melt strength, which drops from about 34.1 cN to 6.3 cN. The melt flow rate increases significantly. This is a sign of polymer degradation due to shear applied during the compounding process and / or the unraveling (release of entanglement) of polymer chains. A similar effect is seen for linear polypropylene l-PP-1 with a very low melt flow rate, but it is not as pronounced. For linear polypropylenes l-PP-2 to l-PP-3 with higher MFR, the effect of the compounding process on the melt flow rate and melt strength is only slight.

[0203] The following melt compounded blends were prepared from the individual components. Comparative Example CE1: 100 wt% b-PP Comparative Example CE2: 60 wt% b-PP + 40 wt% l-PP-1 Inventive Example IE1: 60 wt% b-PP + 40 wt% l-PP-2 Inventive Example IE2: 60 wt% b-PP + 40 wt% l-PP-3 Inventive Example IE3: 60 wt% b-PP + 40 wt% l-PP-4

[0204] [Table 2]

[0205] Examples IE1 to IE3 show a higher melt strength than expected based on the melt strength measured for the individual components after compounding. The higher melt strength is achieved in combination with a high melt flow rate. Examples IE1 to IE3 show a lower shear viscosity index than Examples CE1 and CE2. Example CE2 shows a high melt strength, but the melt flow rate is as low as 0.85 g / 10 min. This low melt flow rate has an adverse effect on the processability of the blend.

[0206] 2) Polypropylene foam The following dry blends were prepared. Comparative Example CE3: 99.2 wt% b-PP + 0.8 wt% AM Inventive Example IE4: 59.2 wt% b-PP + 40.0 wt% l-PP-3 + 0.8 wt% AM Inventive Example IE5: 59.0 wt% b-PP + 40.0 wt% l-PP-3 + 1.0 wt% AM

[0207] Using a dry blend, a low-density polypropylene foam was prepared using a KraussMaffei Berstorff tandem foaming line (ZE40 twin-screw extruder; KE90 single-screw extruder) and isobutane as the blowing agent.

[0208] The blowing agent was used in an amount in the range of 3.5 - 7.0 wt%. The twin-screw extruder was operated at a temperature in the range of 20 - 220 °C, a screw speed in the range of 100 - 200 r / min, and a specific output in the range of 0.2 - 0.7 kg / h / r / min. The single-screw extruder was operated at a temperature in the range of 20 - 190 °C, a screw speed in the range of 2 - 15 r / min, and a specific output in the range of 5 - 20 kg / h / r / min.

[0209] The foam properties are summarized in Table 3 below.

[0210]

Table 3

[0211] As shown in Table 3, the dry blend of Example IE4 can be foamed into a low-density polypropylene foam using a commercial extrusion foaming process. Furthermore, using the same process settings, blends containing linear polypropylene l-PP-3 were observed to exhibit lower pressure levels at the exit of the extruder ZE40 and at the die, confirming better processability due to the higher melt flow rate of the blend compared to that of CE3.

Claims

1. A polypropylene composition for preparing a foam, wherein the polypropylene composition comprises (a) at least 40.0% by weight of a long-chain branched polypropylene, and (b) at least 30.0% by weight of a linear polypropylene wherein the amounts by weight are based on the total weight of the polypropylene composition, The polypropylene composition has a melt flow rate MFR in the range of 2.5 to 30.0 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C), and is a polypropylene composition.

2. The polypropylene composition comprises (a) 50.0 to 70.0% by weight, preferably 55.0 to 65.0% by weight, more preferably 57.5 to 62.5% by weight of the long-chain branched polypropylene, and (b) 30.0 to 50.0% by weight, preferably 35.0 to 45.0% by weight, more preferably 37.5 to 42.5% by weight of the linear polypropylene, and (c) optionally, 0.1 to 4.0% by weight, preferably 0.2 to 3.0% by weight, more preferably 0.2 to 2.0% by weight of one or more additives wherein all amounts by weight are based on the total weight of the polypropylene composition, and optionally, components (a) to (c) together amount to 100% by weight The polypropylene composition according to claim 1.

3. The polypropylene composition has one or more, preferably two or more, more preferably all of the following properties i) A melt strength F in the range of at least 5.0 cN, preferably in the range of 5.0 to 30.0 cN, more preferably in the range of 5.0 to 27.5 cN, and even more preferably in the range of 5.0 to 23.0 cN ３０ (ISO 16790:2005), ii) A melt flow rate MFR in the range of 3.0 to 20.0 g / 10 min, for example in the range of 3.0 to 16.0 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C), and iii) A melt drawability v in the range of 180 to 320 mm / s, preferably 200 to 280 mm / s, more preferably 220 to 260 mm / s ３０ (ISO 16790:2005) The polypropylene composition according to claim 1 or claim 2.

4. The polypropylene composition has a shear viscosity reduction index SHI determined as described in the specification in the range of less than 40.0, preferably from 10.0 to less than 40.0 （０．０５／３００） The polypropylene composition according to any one of claims 1 to 3 having the same.

5. The polypropylene composition according to any one of claims 1 to 4, wherein the long-chain branched polypropylene is a long-chain branched propylene homopolymer.

6. The polypropylene composition according to any one of claims 1 to 5, wherein the linear polypropylene is a linear propylene homopolymer.

7. The polypropylene composition according to any one of claims 1 to 6, wherein the polypropylene composition contains one or more additives, and the one or more additives include a nucleating agent, preferably talc as a nucleating agent.

8. The long-chain branched polypropylene has one or more, preferably two or more, more preferably all 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) The 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 polypropylene composition according to any one of claims 1 to 7, which is derived from a long-chain branched polypropylene starting material.

9. The long-chain branched polypropylene is preferably derived from a long-chain branched polypropylene starting material obtained by treating linear polypropylene with a radical-forming agent in the presence of a difunctional unsaturated monomer and / or a polyfunctional unsaturated low molecular weight polymer. The polypropylene composition according to any one of claims 1 to 8.

10. The linear polypropylene is derived from a linear polypropylene starting material having one or more, preferably two or more, more preferably all of the following properties. The polypropylene composition according to any one of claims 1 to 9. i) a melt strength F of at most 15.0 cN, preferably at most 10.0 cN, more preferably at most 8.0 cN ３０ (ISO 16790:2005), ii) A melt drawability v of at most 210 mm / s, preferably at most 200 mm / s, more preferably at most 190 mm / s ３０ (ISO 16790:2005), iii) A melt flow rate MFR in the range of 2.0 to 50.0 g / 10 min, preferably 2.5 to 40.0 g / 10 min, more preferably 2.8 to 30.0 g / 10 min ２ (ISO 1133, 2.16 kg load, 230 °C)

11. The polypropylene composition can be obtained or is obtained using a mixture, preferably a dry blend, comprising a long-chain branched polypropylene starting material and a linear polypropylene starting material. The linear polypropylene starting material has the following properties i) The melt flow rate MFR of the long-chain branched polypropylene starting material ２ is higher than the melt flow rate MFR (ISO 1133, 2.16 kg load, 230 °C) ２ (ISO 1133, 2.16 kg load, 230 °C), and ii) The melt strength F of the long-chain branched polypropylene starting material ３０ having a melt strength F lower than that specified in ３０ ISO 16790:2005 The polypropylene composition according to any one of claims 1 to 10.

12. A foam comprising the polypropylene composition according to any one of claims 1 to 11.

13. 100 kg / m ３ Hereinafter, preferably 20 to 100 kg / m ３ The foam according to claim 12, having a density measured in accordance with 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 23.0 cN, preferably 5.0 to 23.0 cN ３０ (ISO 16790:2005), ii) A shear thinning index SHI as determined as described in the specification and less than 40.0, preferably in the range of from 10.0 to less than 40.0 （０．０５／３００） The foam according to claim 12 or claim 13.

15. A method for preparing the polypropylene composition according to any one of claims 1 to 11 or the foam according to any one of claims 12 to 14, comprising: a) providing a mixture comprising a long-chain branched polypropylene starting material, a linear polypropylene starting material, and optionally one or more additives; b) melt-blending the mixture provided in step a) to obtain a polypropylene composition; and c) optionally, foaming the melt-blended mixture provided in step b) to obtain a foam.

16. Use of the polypropylene composition according to any one of claims 1 to 11 for preparing a foam.

Images