Composition comprising polypropylene and polyethylene

Abstract

The present invention relates to a polyolefin composition comprising a high melt strength polypropylene and a polyethylene wherein the high melt strength polypropylene is obtained or obtainable by a process comprising melt mixing a base polypropylene, a peroxide and a linear alpha-olefin composition comprising a linear C20 + alpha-olefin.

Description

[0001] This invention relates to polyolefin compositions comprising polypropylene and polyethylene, and articles comprising such compositions.

[0002] Compositions of polypropylene and polyethylene are desirable because they allow for tuning of material properties by selecting the type and amount of individual components. However, polyethylene and polypropylene are known to be immiscible. Furthermore, it is disadvantageous that polypropylene and polyethylene do not interact substantially, meaning that blends of polyethylene and polypropylene typically result in a two-phase system with both a polypropylene phase and a polyethylene phase, exhibiting poor physical properties.

[0003] Therefore, attempts have been made to increase the interaction between the phases in such blends by adding compatibilizers. Compatibilizers are materials that have an affinity for both phases and enhance the bonding strength. As a result, materials with improved properties can be obtained.

[0004] Blends of polypropylene and polyethylene containing compatibilizers are known in the art. For example, US 6,114,443 discloses compositions comprising blends of polyethylene and isotactic polyalphaolefin homopolymers (e.g., polypropylene), and diblock copolymer compatibilizers of polyethylene blocks and random polyalphaolefin blocks.

[0005] WO2016188818 discloses a composition comprising polypropylene, polyethylene, and a compatibilizer as a non-aromatic polyester.

[0006] Given the favorable combination of mechanical properties and cost, there is a continued demand for additional compositions that can be manufactured relatively easily and at low cost.

[0007] Therefore, the object of the present invention is to provide a composition comprising polypropylene and polyethylene, which has good mechanical properties.

[0008] Therefore, the present invention provides a polyolefin composition comprising high melt strength polypropylene and polyethylene, wherein the high melt strength polypropylene is obtained or can be obtained by a method comprising melt mixing a base polypropylene, a peroxide and a linear α-olefin composition comprising a linear C20+ α-olefin.

[0009] Surprisingly, it has been found that the high melt strength polypropylene used according to the present invention can be blended with polyethylene to obtain a composition with good mechanical properties without the need for a compatibilizer.

[0010] Linear C20+ α-olefins, as used herein, refer to linear α-olefins having 20 or more carbon atoms. Linear C20+ α-olefins used to prepare high melt strength polypropylene according to the present invention are typically obtained as byproducts of methods for preparing more commonly used low-carbon α-olefins. Linear C20+ α-olefins generally have relatively limited uses, such as lubricants and waxes. The present invention is highly advantageous in that it has discovered new applications for these byproducts.

[0011] High melt strength polypropylene

[0012] According to the present invention, the melt mixing of base polypropylene with peroxide and a linear α-olefin composition comprising linear C20+ α-olefin results in the grafting of linear C20+ α-olefin onto the propylene polymer backbone, thereby obtaining polypropylene with high melt strength.

[0013] Preferably, the method for obtaining high melt strength polypropylene does not include adding inorganic nanofillers, such as silica, organic clay and carbon nanotubes, before, during and / or after the melt mixing step.

[0014] Preferably, the method for obtaining high melt strength polypropylene does not involve irradiating the polypropylene with an electron beam before, during, and / or after the melt mixing step. This advantageously avoids undesirable degradation of the polypropylene.

[0015] Basic polypropylene

[0016] The polypropylene to be melt-mixed with a composition of peroxide and linear α-olefin to obtain high melt strength polypropylene is referred to herein as basic polypropylene.

[0017] The base polypropylene may be or comprise a propylene homopolymer, a random propylene copolymer, or a heteropolymer of propylene, or any combination thereof. In some preferred embodiments, the base polypropylene is a propylene homopolymer. In some preferred embodiments, the base polypropylene is a random propylene copolymer.

[0018] Propylene homopolymers can be obtained by polymerizing propylene under suitable polymerization conditions. Propylene copolymers can be obtained by copolymerizing propylene with ethylene or one or more other α-olefins under suitable polymerization conditions. The preparation of propylene homopolymers and copolymers is described, for example, in Moore, EP (1996) Polypropylene Handbook. Polymerization, Characterization, Properties, Processing, Applications, Hanser Publishers: New York.

[0019] The random propylene copolymer may contain ethylene as a comonomer or an α-olefin selected from α-olefins having 4 to 12 carbon atoms, preferably ethylene, 1-butene, 1-hexene, 1-octene, or any mixture thereof. The amount of comonomer based on the random propylene copolymer is preferably up to 10 wt%, for example, in the range of 2.0 to 7.0 wt% based on the random propylene copolymer. In a particularly preferred embodiment, the random propylene copolymer is a propylene-ethylene random copolymer, preferably wherein the amount of ethylene comonomer units is 2.0 to 7.0 wt% based on the random propylene copolymer.

[0020] Heterogeneous propylene copolymers are typically prepared in one or more reactors by polymerizing propylene in the presence of a catalyst, followed by polymerizing an ethylene-α-olefin mixture. The resulting polymer material is heterogeneous, but its specific morphology usually depends on the preparation method and monomer ratio used.

[0021] Heterogeneous propylene copolymers comprise a propylene-based matrix and a dispersed ethylene-α-olefin copolymer. The propylene-based matrix typically forms the continuous phase in the heterogeneous propylene copolymer. The propylene-based matrix consists of propylene homopolymers and / or propylene copolymers comprising at least 90 wt% propylene monomer units and at most 10 wt% ethylene and / or α-olefin monomer units, based on the total weight of the propylene-based matrix. The α-olefin in the dispersed ethylene-α-olefin copolymer is preferably selected from α-olefins having 3 to 8 carbon atoms, preferably propylene.

[0022] Preferably, the base polypropylene has a melt flow index of 0.1 to 10 dg / min, as determined according to ISO 1133-1:2022 at 230°C and 2.16 kg.

[0023] Preferably, the base polypropylene has a strength of 895 to 930 kg / m³ as determined according to ASTM D1505. 3 For example, 895 to 900 kg / m 3 Or 900 to 915 kg / m 3 The density.

[0024] In some implementations, the base polypropylene has a strength of 900 to 915 kg / m³ as determined according to ASTM D1505. 3 propylene homopolymer of a certain density.

[0025] In some implementations, the base polypropylene has a strength of 895 to 900 kg / m³ as determined according to ASTM D1505. 3 Random propylene copolymers with a density of [missing information].

[0026] The base polypropylene may be or contain post-consumption recycled (PCR) polypropylene.

[0027] Linear α-olefin compositions

[0028] The linear α-olefin composition comprises a linear α-olefin. Preferably, the amount of linear α-olefin in the linear α-olefin composition is at least 95 wt%, at least 97 wt%, at least 99 wt%, at least 99.5 wt%, or 100 wt%.

[0029] Preferably, the amount of linear C20+ α-olefin is at least 55 wt% relative to the amount of linear α-olefin in the linear α-olefin composition, preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, and more preferably at least 95 wt%.

[0030] The linear α-olefin composition may contain C20-C30 linear α-olefins and C30+ linear α-olefins.

[0031] Preferably, the amount of C20-C30 linear α-olefin is at least 55 wt% relative to the amount of linear α-olefin in the linear α-olefin composition, preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, for example 80 to 99 wt%, 80 to 95 wt%, or 80 to 90 wt%.

[0032] Preferably, the amount of C20-C24 linear α-olefins is 50 to 90 wt% or 65 to 75 wt% relative to the total linear α-olefins in the linear α-olefin composition, and the amount of C26-C28 linear α-olefins is 5.0 to 25 wt% or 15 to 25 wt% relative to the total linear α-olefins in the linear α-olefin composition.

[0033] Preferably, the amount of C30+ linear α-olefin is up to 20 wt% relative to the amount of linear α-olefin in the linear α-olefin composition, for example, 1.0 to 15 wt% or 3.0 to 10 wt%.

[0034] The linear α-olefin composition may further comprise linear C4-C19 α-olefins.

[0035] Preferably, the amount of C4-C19 linear α-olefin is at most 5.0 wt% relative to the linear α-olefin in the linear α-olefin composition, for example, 0.1 to 5.0 wt% or 0.5 to 3.0 wt%.

[0036] In a particularly preferred embodiment,

[0037] The amount of linear C4-C19 α-olefins is from 0.1 to 5.0 wt% relative to the total linear α-olefins in the linear α-olefin composition.

[0038] The amount of linear C20-C24 α-olefins is 65 to 80 wt% relative to the amount of linear α-olefins in the composition.

[0039] The amount of linear C26-C28 α-olefins is 10 to 20 wt% relative to the amount of linear α-olefins in the composition.

[0040] The amount of linear C30+ α-olefin is 3.0 to 10 wt% relative to the amount of linear α-olefin in the linear α-olefin composition.

[0041] Preferably, the amount of the linear α-olefin composition is 0.5 to 10 wt% relative to the base polypropylene, more preferably 1.0 to 5.0 wt%.

[0042] Preferably, the amount of linear C20+ α-olefin is 0.5 to 10 wt% relative to the base polypropylene, more preferably 1.0 to 5.0 wt%.

[0043] Preferably, the amount of linear C20-C30 α-olefin is 0.5 to 10 wt% relative to the base polypropylene, more preferably 1.0 to 5.0 wt%.

[0044] peroxide

[0045] The peroxide can be any known peroxide used to increase the melt flow of polypropylene. Peroxides may be selected from, for example, 2,5-dimethyl-2,5-bis(tert-butyl-peroxy)hexane (DHBP) (e.g., sold under the trade names Luperox 101 and Trigonox 101), 2,5-dimethyl-2,5-bis(tert-butyl-peroxy)hexyn-3 (DYBP) (e.g., sold under the trade names Luperox 130 and Trigonox 145), dicumyl-peroxide (DCUP) (e.g., sold under the trade names Luperox DC and Perkadox BC), di-tert-butyl-peroxide (DTBP) (e.g., sold under the trade names Trigonox B and Luperox Di), tert-butyl-cumyl-peroxide (BCUP) (e.g., sold under the trade names Trigonox T and Luperox 801), and 1,3-bis(tert-butylperoxy-isopropyl)benzene (DIPP) (e.g., sold under the trade names Perkadox 14S and Luperox DC).

[0046] Preferably, the amount of peroxide is 0.01 to 1.00 wt% relative to the base polypropylene, more preferably 0.05 to 0.50 wt%.

[0047] polyethylene

[0048] Polyethylene can be any one or a combination of high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and low-density polyethylene (LDPE). The production methods of HDPE, LLDPE, and LDPE are summarized in Andrew Peacock's Handbook of Polyethylene (2000; Dekker; ISBN 0824795466), pages 43-66.

[0049] Polyethylene may be or contain post-consumption recycled (PCR) polyethylene.

[0050] HDPE

[0051] Polyethylene may be or contain HDPE.

[0052] HDPE can be an ethylene homopolymer or may contain comonomers such as 1-butene or 1-hexene.

[0053] Preferably, the HDPE has a strength of 940-960 kg / m³ as measured according to ASTM D1505. 3 More preferably 940-955 kg / m 3 The density.

[0054] Preferably, the HDPE has a melt flow index of 0.1-4.0 g / 10 min, more preferably 0.1-1.0 g / 10 min, as determined according to ISO 1133-1:2022 at 190°C and 5 kg.

[0055] Preferably, the HDPE has a melt flow index of 5.0-15 g / 10min, more preferably 0.1-1.0 g / 10min, as determined according to ISO 1133-1:2022 at 230°C and 21.6 kg.

[0056] LLDPE

[0057] Polyethylene may be or contain LLDPE.

[0058] Suitable technologies for LLDPE manufacturing include gas-phase fluidized bed polymerization, solution polymerization, polymerization in a polymer melt under very high ethylene pressure, and slurry polymerization.

[0059] LLDPE comprises ethylene and C3-C10 α-olefin comonomers (ethylene-α-olefin copolymers). Suitable α-olefin comonomers include 1-butene, 1-hexene, 4-methylpentene, and 1-octene. The preferred comonomer is 1-butene.

[0060] Preferably, the amount of α-olefin comonomer present is about 5.0 to about 20 wt% of the ethylene-α-olefin copolymer, more preferably about 7.0 to about 15 wt% of the ethylene-α-olefin copolymer.

[0061] Preferably, LLDPE has a strength of 900-940 kg / m³ as determined by ASTM D1505. 3 More preferably 905-930 kg / m 3 More preferably 910-925 kg / m 3 The density.

[0062] Preferably, the LLDPE has a melt flow index of 0.1 to 3.0 g / 10 min, more preferably 1.0 to 3.0 g / 10 min, as determined according to ISO 1133-1:2022 at 190 °C and 2.16 kg.

[0063] LDPE

[0064] Polyethylene may be or contain LDPE.

[0065] LDPE can be produced using pressure vessel technology and tubular reactor technology.

[0066] LDPE can be an ethylene homopolymer or may contain comonomers such as 1-butene or 1-hexene.

[0067] Preferably, LDPE has a strength of 916-940 kg / m³ as determined by ASTM D1505. 3 More preferably 920-935 kg / m 3 The density.

[0068] Preferably, the LDPE has a melt flow index of 0.1 to 3.0 g / 10 min, more preferably 1.0 to 3.0 g / 10 min, as determined according to ISO 1133-1:2022 at 190 °C and 2.16 kg.

[0069] HMS-PP and PE blend

[0070] According to the present invention, blends of high melt strength polypropylene and polyethylene can be prepared. Therefore, in some preferred embodiments of the invention, the total amount of high melt strength polypropylene and polyethylene is at least 90 wt%, for example, 95 to 99.9 wt%, relative to the total polyolefins in the polyolefin composition.

[0071] The weight ratio between high melt strength polypropylene and polyethylene in the polyolefin composition can be, for example, 5:95 to 95:5, such as 5:95 to 50:50 or 50:50 to 95:5.

[0072] HMS-PP as a compatibilizer for PP and PE

[0073] Furthermore, according to the present invention, high melt strength polypropylene can be used as a compatibilizer for blending polypropylene and polyethylene. Therefore, the present invention provides the use of high melt strength polypropylene as a compatibilizer for blending polypropylene and polyethylene.

[0074] In some embodiments, the polyolefin composition comprises additional polypropylene, wherein the amount of high melt strength polypropylene is 0.5 to 10 wt%, preferably 5 to 10 wt%, relative to the total amount of the additional polypropylene and polyethylene.

[0075] The weight ratio between the total amount of high melt strength polypropylene and additional polypropylene in the polyolefin composition and polyethylene can be, for example, 5:95 to 95:5, such as 5:95 to 50:50 or 50:50 to 95:5.

[0076] As an alternative polypropylene, any type of polypropylene can be used. Suitable examples of alternative polypropylene are those described for the basic polypropylene.

[0077] Optional components

[0078] The polyolefin composition according to the invention can be obtained by melt-blending high melt strength polypropylene and polyethylene, optionally with any other optional components.

[0079] The polyolefin composition may contain components other than high melt strength polypropylene and polyethylene, such as additives and fillers. Examples of additives include nucleating agents; stabilizers, such as heat stabilizers, antioxidants, and UV stabilizers; colorants, such as pigments and dyes; clarifying agents; surface tension modifiers; lubricants; flame retardants; release agents; flow improvers; plasticizers; antistatic agents; external elastomer impact modifiers; foaming agents; and / or components that reinforce the interfacial bonding between the polymer and fillers, such as maleated polyethylene. The amount of additives relative to the total composition is typically 0 to 5.0 wt%, for example, 1.0 to 3.0 wt%.

[0080] Examples of fillers include glass fiber, talc, and mica. The amount of filler relative to the total polyolefin composition may be, for example, 0 to 40 wt%, 5 to 30 wt%, or 10 to 25 wt%.

[0081] Therefore, in some embodiments, the polyolefin composition also contains 0 to 5.0 wt% of additives and 0 to 40 wt% of fillers.

[0082] In some embodiments, the polyolefin composition according to the invention has little or no filler, i.e., the polyolefin composition according to the invention has less than 5.0 wt%, less than 3.0 wt%, less than 1.0 wt%, less than 0.5 wt%, less than 0.1 wt%, or 0 wt% filler.

[0083] Preferably, the total amount of high melt strength polypropylene, polyethylene, optional additives, optional fillers and optional additional polypropylene is 100 wt% relative to the total polyolefin composition.

[0084] The present invention also provides a method for preparing a polyolefin composition according to the invention, comprising melt-blending high melt strength polypropylene and polyethylene, along with optional additives, fillers, and / or additional polypropylene. Some or all of the optional components may be added to the high melt strength polypropylene and / or polyethylene prior to melt-blending the high melt strength polypropylene and polyethylene.

[0085] Pipes

[0086] The present invention also provides articles comprising the compositions according to the invention, preferably molded articles, such as tubes or membranes.

[0087] The pipe may be a multilayer pipe having an innermost layer comprising the composition according to the invention and one or more outer layers.

[0088] In this document, the term "tube" is understood to refer to a hollow, elongated article. The cross-section can be of various shapes, such as circular, elliptical, square, rectangular, or triangular. The tube according to the invention may have an outer diameter ranging from 2.5 to 255 cm and / or an inner diameter ranging from 2 to 250 cm and / or the tube may have one or more layers with a total layer thickness ranging from 0.3 to 100 mm. The outer layer may have a thickness, for example, 0.3 to 50 mm, 1 to 30 mm, or 5 to 20 mm.

[0089] At least one of the outer layers may be made of steel, ceramic, or a polymer. Any type of polymer can be used for the outer layers. Preferably, one or more outer layers comprise polypropylene or polyethylene. Preferably, the outer layer adjacent to the innermost layer comprises polypropylene or polyethylene.

[0090] An adhesive layer may be present between the innermost layer and the adjacent outer layer. This adhesive layer may contain anhydride-grafted or acid-grafted materials. However, the composition according to the invention in the innermost layer eliminates the need for such an adhesive layer when the adjacent outer layer contains polypropylene and / or polyethylene.

[0091] Therefore, in a preferred embodiment, the adjacent outer layer comprises polypropylene and / or polyethylene and is directly bonded to the innermost layer.

[0092] The tubing according to the invention can be produced by any suitable method, such as that described in US9488310. The tubing according to the invention can be produced by tubing extrusion manufacturing methods.

[0093] The membrane may be a multilayer tube having a surface layer (a layer located on the surface of the membrane) comprising the composition according to the invention.

[0094] It should be noted that the present invention relates to the subject matter defined by any possible combination of features, either alone or in conjunction with those features described herein, particularly preferably those combinations of features present in the claims. Therefore, it will be understood that this document describes all combinations of features relating to the compositions according to the invention; all combinations of features relating to the methods according to the invention; and all combinations of features relating to the compositions according to the invention and features relating to the methods according to the invention.

[0095] It should also be noted that the term "comprising" does not exclude the presence of other elements. However, it is also understood that descriptions of products / compositions comprising certain components also disclose products / compositions composed of those components. Products / compositions composed of these components are advantageous because they provide a simpler and more economical method for preparing the product / composition. Similarly, it is also understood that descriptions of methods including certain steps also disclose methods composed of those steps. Methods composed of these steps are advantageous because they provide a simpler and more economical method.

[0096] When the lower and upper limits of a parameter are mentioned, it is also understood that the range made up of the combination of the lower and upper limits is disclosed.

[0097] The invention will now be illustrated by the following embodiments, but is not limited thereto.

[0098] Material:

[0099] hPP1: has a melt flow index of 0.3 dg / min (ISO 1133-1:2022, 230℃, 2.16 kg) and a melt flow rate of 905 kg / m³. 3 A high density propylene homopolymer (SABIC® PP531P)

[0100] rPP1: has a melt flow index of 0.3 dg / min (ISO 1133-1:2022, 230℃, 2.16 kg) and a melt flow rate of 898 kg / m³. 3 Random propylene-ethylene copolymer with a density of 4 wt% ethylene content (SABIC® Vestolen P9421)

[0101] LAO: A linear α-olefin composition having the following composition:

[0102]

[0103] The IR absorption of the LAO sample is at 1642 cm⁻¹. -1 The strong absorption at this point is attributed to the unsaturated (C=C) functional groups present in LAO.

[0104] Peroxide: Polypropylene masterbatch containing 40 wt% 1,3-bis(tert-butylperoxyisopropyl)benzene

[0105] The materials shown in Table 1 are melt-mixed at 200°C for 8 minutes.

[0106] The obtained polypropylene was subjected to FTIR testing to confirm that the C20+ linear α-olefin had been grafted onto the polypropylene. Samples prepared using LAO and peroxide were analyzed at 720 cm⁻¹. -1 A peak was observed at [location], while samples prepared using peroxide but not LAO did not. The grafting percentage was quantified by counting the ethylene imprint content.

[0107] The rheological behavior of polypropylene samples was studied using an ARES rheometer, which employs rotational force to measure the storage modulus, loss modulus, and complex viscosity. The temperature was fixed at 180 °C, and the frequency was increased from 0.5 rad / s to 500 rad / s, with complex viscosity, storage modulus, and loss modulus measured at each frequency. The zero-shear viscosity was extrapolated from the results and is shown in Table 1.

[0108] The MFI of the samples was measured at 230°C and 2.16 kg according to ISO 1133-1 (2022) and is shown in Table 1.

[0109] Table 1

[0110]

[0111] Polypropylene obtained by adding the C20+ linear α-olefin according to the invention has a higher zero-shear viscosity than the corresponding polypropylene obtained without adding the C20+ linear α-olefin, indicating that the polypropylene obtained by adding the α-olefin has higher melt strength.

[0112] The obtained polypropylene sample was melt-mixed with polyethylene at 220°C for 6 minutes to obtain the composition shown in Table 2.

[0113] PE1: Has a melt flow index of 2 dg / min (ISO 1133-1:2022, 190℃, 2.16 kg) and a melt flow rate of 918 kg / m³. 3 LLDPE of a certain density, comonomer: 1-butene (SABIC® LLDPE 218B)

[0114] The elongation at break was measured according to ASTM D638, and the results are shown in Table 2.

[0115] Table 2

[0116]

[0117] The composition of Comparative Example 11, prepared by blending PE with peroxide-treated polypropylene of Comparative Example 4, has a lower elongation at break than the composition of Comparative Example 10, prepared by blending PE with untreated PP.

[0118] The composition of Example 12, prepared by blending PE with high melt strength polypropylene grafted with α-olefins, has a higher elongation at break than the compositions of Comparative Examples 10 and 11.

Claims

1. A polyolefin composition comprising high melt strength polypropylene and polyethylene, wherein the high melt strength polypropylene is obtained or is obtainable by a method comprising melt mixing a base polypropylene, a peroxide and a linear α-olefin composition comprising a linear C20+ α-olefin.

2. The composition of claim 1, wherein the base polypropylene comprises or is a propylene homopolymer.

3. The composition according to any one of the preceding claims, wherein the base polypropylene comprises or is a random copolymer of propylene and a comonomer selected from ethylene and C4-C12 α-olefins, preferably a random propylene-ethylene copolymer.

4. The composition according to any one of the preceding claims, wherein the base polypropylene has a melt flow index of 0.1 to 10 dg / min as determined according to ISO 1133-1:2022 at 230°C and 2.16 kg.

5. The composition according to any one of the preceding claims, wherein The amount of linear C20+ α-olefin relative to the amount of linear α-olefin in the linear α-olefin composition is at least 55 wt%, preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, and more preferably at least 95 wt%. Preferably, the linear α-olefin composition further comprises a linear C4-C19 α-olefin in an amount of up to 5.0 wt%, for example 0.1 to 5.0 wt%, or 0.1 to 3.0 wt%, relative to the linear α-olefin in the linear α-olefin composition.

6. The composition according to any one of the preceding claims, wherein the amount of C20-C24 linear α-olefin is 50 to 90 wt% or 65 to 75 wt% relative to the amount of linear α-olefin in the linear α-olefin composition, and the amount of C26-C28 linear α-olefin is 5.0 to 25 wt% or 15 to 25 wt% relative to the amount of linear α-olefin in the linear α-olefin composition.

7. The composition according to any one of the preceding claims, wherein the amount of linear C20+ α-olefin is 0.5 to 10 wt%, more preferably 1.0 to 5.0 wt%, relative to the base polypropylene.

8. The composition according to any one of the preceding claims, wherein the amount of said peroxide is 0.01 to 1.00 wt% relative to the base polypropylene, more preferably 0.05 to 0.50 wt%.

9. The composition according to any one of the preceding claims, wherein the polyethylene is selected from high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and low-density polyethylene (LDPE) and combinations thereof.

10. The composition according to any one of the preceding claims, wherein the polyethylene has a melt flow index of 0.1 to 10 dg / min as determined according to ISO 1133-1:2022 at 190°C and 2.16 kg.

11. The composition according to any one of claims 1 to 10, wherein the total amount of the high melt strength polypropylene and polyethylene is at least 90 wt% relative to the total polyolefins in the polyolefin composition, for example, 95 to 99.9 wt%.

12. The composition according to any one of claims 1 to 10, wherein the polyolefin composition comprises additional polypropylene, wherein the amount of the high melt strength polypropylene is 0.5 to 10 wt%, preferably 5 to 10 wt%, relative to the total amount of the additional polypropylene and the polyethylene.

13. Use of high melt strength polypropylene as a compatibilizer for blending polypropylene and polyethylene, wherein the high melt strength polypropylene is obtained or can be obtained by a method comprising melt-blending a base polypropylene, a peroxide and a linear α-olefin composition comprising a linear C20+ α-olefin.

14. An article comprising the composition according to any one of claims 1 to 12, preferably wherein the article is selected from tubing and membranes.

15. The article of claim 14, wherein the article is a multilayer tubing having an innermost layer comprising the composition and one or more outer layers, preferably wherein adjacent outer layers comprise polypropylene and / or polyethylene and are directly bonded to the innermost layer.

Images