Propylene-ethylene random copolymers for pipeline applications

Abstract

A single-phase propylene-ethylene random copolymer composition (R-PP) having an MFR2 of from 0.01 to 1.00 g / 10 min, a C2 content of from 1.5 to 7.5 mol%, a Tm of from 120 to 150 DEG C, a 2, 1-region defect content of from 0.05 to 1.20 mol%, and a propylene-ethylene random copolymer composition (R-PP) having a molecular weight of from 20 to 30, mw / Mn is in the range of 2.00 to 5.00.

Description

Technical Field

[0001] The present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP), a method for obtaining the single-phase propylene-ethylene random copolymer composition (R-PP), and an article comprising the single-phase propylene-ethylene random copolymer composition (R-PP). Background Art

[0002] Polypropylene, particularly propylene random copolymers, is a versatile synthetic polymer that combines beneficial mechanical properties with ideal processing characteristics. These beneficial properties have led to polypropylene being used in applications such as films, automotive products, sanitary products, and pipes.

[0003] Polypropylene has long been used in pipe production due to its excellent resistance to physical damage (at both high and low temperatures), corrosion, and chemical leaching, and the fact that polypropylene pipes can be joined by heat fusion rather than gluing. Despite its numerous advantages, the production of polypropylene for pipe applications does have limitations.

[0004] Polypropylene for pipe applications must have a relatively high molecular weight (e.g., an MFR2 below about 0.50 g / 10 min) to achieve the required mechanical properties. Many catalysts, particularly single-site catalysts, are unable to achieve such high molecular weights, regardless of the amount of hydrogen (i.e., the molecular weight controller) used during the polymerization process. Another problem stems from the sensitivity of single-site catalysts to hydrogen (i.e., the molecular weight controller), meaning that small differences in the amount of hydrogen can lead to considerable fluctuations in the polymerization process.

[0005] While Ziegler-Natta catalysis can address many of these issues, other problems, including high extractables levels and poor long-term pressure performance, mean that this strategy cannot fully meet the demand for improved polypropylene compositions for pipeline applications.

[0006] EP 3 567 061 A1 discloses trimodal propylene-1-hexene random copolymers for pipe applications, wherein the inventive composition combines excellent mechanical properties with high comonomer incorporation. The comonomer used (1-hexene) increases the cost and complexity of producing the composition.

[0007] EP 2 788 181 A1 discloses a propylene-ethylene-1-hexene copolymer having mechanical and rheological properties similar to those of a comparative copolymer, but exhibiting some limited improvement in pipe performance (e.g., impact testing and internal pressure resistance). However, it suffers from similar disadvantages to the previous copolymer.

[0008] EP 3 147 324 A1 discusses the effect of adding long-chain branched propylene homopolymers to propylene random copolymer compositions (e.g., Borealis brand RA130E) to improve compression resistance. However, the production of long-chain branched propylene homopolymers requires a separate reactive modification step, which increases the cost and complexity of producing the composition.

[0009] Despite the significant progress that has been made in the field of polypropylene pipes, there is still a need for further compositions that meet the requirements of low extractables content and excellent mechanical properties, in particular long-term compressive resistance. Summary of the Invention

[0010] The present invention is based on the discovery that a balance of low melt flow rate (MFR2), low extractables content (eg XCS content) and impressive long-term compression resistance can be achieved for specific propylene-ethylene copolymers produced using single-site catalysis.

[0011] In a first aspect, the present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP), wherein the single-phase propylene-ethylene random copolymer composition has:

[0012] i) a melt flow rate (MFR2) in the range of 0.01 to 1.00 g / 10 min, measured at 230° C. under a 2.16 kg load according to ISO 1133;

[0013] ii) According to 13 an ethylene content (C2) in the range of 1.5 to 7.5 mol %, determined by C-NMR spectroscopy;

[0014] iii) a melting temperature (Tm) in the range of 120 to 150° C. as determined by DSC analysis;

[0015] iv) By quantitative 13 a 2,1-regio defect content in the range of 0.05 to 1.20 mol % as determined by C-NMR spectroscopy; and

[0016] v) a molecular weight distribution (Mw / Mn) in the range of 2.00 to 5.00 as determined by gel permeation chromatography (GPC).

[0017] In a second aspect, the present invention relates to a method for obtaining the single-phase propylene-ethylene random copolymer composition (R-PP) according to the first aspect, the method comprising the following steps:

[0018] a) polymerizing propylene and ethylene comonomer units in the presence of a single site catalyst in a first polymerization reactor to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and the single site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor;

[0019] b) removing the first polymerization mixture from the first polymerization reactor, optionally performing steps c1) to c3), and then performing step d);

[0020] c1) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor;

[0021] c2) polymerizing propylene and ethylene comonomer units in the presence of the single site catalyst in the second polymerization reactor to produce a second polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2), and the single site catalyst;

[0022] c3) removing the second polymerization mixture from the second polymerization reactor; and

[0023] d) compounding the first polymerization mixture if steps c1) to c3) are absent, or the second polymerization mixture if steps c1) to c3) are present, optionally adding additive (A).

[0024] In a final aspect, the present invention relates to an article comprising at least 75 wt.% of the single-phase propylene-ethylene random copolymer composition (R-PP) of the first aspect.

[0025] definition

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in practice to test the present invention, preferred materials and methods are described herein. In describing and claiming the present invention, the following terms will be used in accordance with the definitions listed below.

[0027] Unless expressly stated otherwise, use of the terms "a," "an," etc. refers to more than one.

[0028] Unless otherwise stated, the amounts below are given as weight percent (wt %).

[0029] Propylene homopolymers are polymers consisting mainly of propylene monomer units. Due to impurities, especially impurities in commercial polymerization processes, propylene homopolymers may contain up to 0.1 mol% of comonomer units, preferably up to 0.05 mol% of comonomer units, most preferably up to 0.01 mol% of comonomer units.

[0030] Propylene random copolymers are copolymers of propylene monomer units and comonomer units, preferably selected from ethylene and C4-C8 α-olefins, wherein the comonomer units are randomly distributed along the polymer chain. Propylene random copolymers may contain comonomer units of more than one comonomer having different amounts of carbon atoms.

[0031] In the context of the present invention, the term "propylene-ethylene random copolymer" means that no other comonomers besides propylene and ethylene are present in the copolymer. Thus, terpolymers (e.g., propylene-ethylene-1-hexene terpolymer) are not included in this definition.

[0032] A typical feature of single-phase propylene homopolymers and single-phase propylene random copolymers is the presence of only one glass transition temperature. No dispersed particles of an elastic second phase having a second glass transition temperature are present.

[0033] Bimodal polymers are polymers having a bimodal distribution of more than one property.Bimodal random propylene-ethylene copolymers may generally be bimodal in ethylene content or may be bimodal in molecular weight (as evidenced by the melt flow rate of the first part and the final composition). DETAILED DESCRIPTION

[0034] Single-phase propylene-ethylene random copolymer composition (R-PP)

[0035] The single-phase propylene-ethylene random copolymer composition (R-PP) has a melt flow rate (MFR2) in the range of 0.01 to 1.00 g / 10 min, more preferably in the range of 0.05 to 0.70 g / 10 min, most preferably in the range of 0.10 to 0.40 g / 10 min, as measured at 230°C under a load of 2.16 kg according to ISO 1133. Also preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a melt flow rate (MFR2) in the range of 0.01 to 0.70 g / 10 min, more preferably in the range of 0.01 to 0.40 g / 10 min, as measured at 230°C under a load of 2.16 kg according to ISO 1133.

[0036] The single-phase propylene-ethylene random copolymer composition (R-PP) is prepared by 13The ethylene content (C2) determined by C-NMR spectroscopy is in the range of 1.5 to 7.5 mol%, more preferably in the range of 2.5 to 6.5 mol%, most preferably in the range of 3.5 to 5.5 mol%.

[0037] The melting temperature (Tm) of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by DSC analysis is in the range of 120 to 150°C, more preferably in the range of 122 to 145°C, most preferably in the range of 125 to 140°C.

[0038] The molecular weight distribution (Mw / Mn) of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by gel permeation chromatography (GPC) is in the range of 2.00 to 5.00, more preferably in the range of 2.40 to 4.80, most preferably in the range of 2.50 to 4.70. Particularly preferably, the molecular weight distribution (Mw / Mn) of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by gel permeation chromatography (GPC) is in the range of 2.90 to 5.00, more preferably in the range of 2.90 to 4.80, most preferably in the range of 2.90 to 4.70.

[0039] The single-phase propylene-ethylene random copolymer composition (R-PP) preferably has a xylene cold soluble content (XCS), determined according to ISO 16152, in the range of 0.10 to 5.0 wt.-%, more preferably in the range of 0.20 to 3.0 wt.-%, most preferably in the range of 0.30 to 1.0 wt.-%. Particularly preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a xylene cold soluble content (XCS), determined according to ISO 16152, in the range of 0.10 to 1.0 wt.-%, more preferably in the range of 0.20 to 1.0 wt.-%, most preferably in the range of 0.30 to 1.0 wt.-%.

[0040] The crystallization temperature (Tc) of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by DSC analysis is preferably in the range of 80 to 110°C, more preferably in the range of 85 to 105°C, most preferably in the range of 90 to 100°C.

[0041] As stated above, the term "propylene-ethylene random copolymer" indicates that no other comonomers can be present. Hence, the single-phase propylene-ethylene random copolymer composition (R-PP) consists essentially of monomer units derived from propylene and ethylene.

[0042] The term "2,1 regio defect" as used in the present invention is defined as the sum of 2,1 erythro regio defects and 2,1 threo regio defects.

[0043] The presence of 2,1-regio defects in the single-phase propylene-ethylene random copolymer composition (R-PP) indicates that the single-phase propylene-ethylene random copolymer composition (R-PP) is polymerized in the presence of a single site catalyst (SSC).

[0044] Therefore, the single-phase propylene-ethylene random copolymer composition (R-PP) is preferably polymerized in the presence of a single site catalyst (SSC), more preferably in the presence of a metallocene catalyst.

[0045] The single-phase propylene-ethylene random copolymer composition (R-PP) was quantitatively 13 The content of 2,1-regio defects determined by C-NMR spectroscopy is in the range of 0.05 to 1.20 mol %, more preferably in the range of 0.10 to 1.00 mol %, and most preferably in the range of 0.15 to 0.90 mol %.

[0046] The content of 2,1-regio defects may depend on the amount of comonomer, with higher amounts of comonomer generally being associated with lower content of 2,1-regio defects.

[0047] The content of 2,1-regio defects may also depend on the polymerization temperature, with higher temperatures generally being associated with lower content of 2,1-regio defects.

[0048] Since the single-phase propylene-ethylene random copolymer composition (R-PP) is not a heterogeneous system containing an elastic rubber layer, the glass transition temperature of the single-phase propylene-ethylene random copolymer composition (R-PP) is preferably not lower than -30°C, more preferably not lower than -25°C, most preferably not lower than -20°C.

[0049] The single-phase propylene-ethylene random copolymer composition (R-PP) was prepared according to ISO 178 using a 80×10×4 mm2 injection molded according to ISO 19069-2. 3 The flexural modulus measured on the test bars is preferably in the range of 500 to 1500 MPa, more preferably in the range of 700 to 1200 MPa, most preferably in the range of 800 to 1000 MPa.

[0050] The single-phase propylene-ethylene random copolymer composition (R-PP) was prepared at +23°C according to ISO 179 / 1eA using 80×10×4 mm2 injection molded according to ISO 19069-2. 3 The Charpy notched impact strength (NIS) measured by the test bar is preferably in the range of 5.0 to 20.0 kJ / m 2 in the range of 7.0 to 15.0 kJ / m 2 The range of 8.0 to 12.0 kJ / m 2Particularly preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) is molded at +23°C according to ISO 179 / 1eA using an 80×10×4 mm 3 The Charpy notched impact strength (NIS) measured by the test bar is preferably in the range of 7.0 to 20.0 kJ / m 2 in the range of 8.0 to 20.0 kJ / m 2 within the range.

[0051] In a specific embodiment, the single-phase propylene-ethylene random copolymer composition (R-PP) is a unimodal propylene-ethylene random copolymer. This means that the single-phase propylene-ethylene random copolymer composition (R-PP) is unimodal with respect to all measurable properties, including molecular weight and ethylene content.

[0052] The fact that the single-phase propylene-ethylene random copolymer composition (R-PP) is unimodal does not exclude the presence of additives known in the art; however, these remainders should not exceed 5.0 wt.%, preferably not exceed 3.0 wt.%, for example not exceed 2.0 wt.% in the single-phase propylene-ethylene random copolymer composition (R-PP). For example, the single-phase propylene-ethylene random copolymer composition (R-PP) may additionally comprise small amounts of additives (A) selected from antioxidants, stabilizers, fillers, colorants, nucleating agents and antistatic agents. Generally speaking, they can be incorporated during the compounding process of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0053] In a specific embodiment the monophasic propylene-ethylene random copolymer composition (R-PP) is a bimodal propylene-ethylene random copolymer.

[0054] In said embodiment, the single-phase propylene-ethylene random copolymer composition (R-PP) comprises from 40 to 70 wt.-% of a first propylene-ethylene random copolymer fraction (R-PP1) and from 30 to 60 wt.-% of a second propylene-ethylene random copolymer fraction (R-PP2), relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0055] More preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) comprises from 45 to 65 wt.-% of the first propylene-ethylene random copolymer fraction (R-PP1) and from 35 to 55 wt.-% of the second propylene-ethylene random copolymer fraction (R-PP2), relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0056] In particular it is preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) comprises from 50 to 63 wt.-% of the first propylene-ethylene random copolymer fraction (R-PP1) and from 37 to 50 wt.-% of the second propylene-ethylene random copolymer fraction (R-PP2), relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0057] The first propylene-ethylene random copolymer fraction (R-PP1) and the second propylene-ethylene random copolymer fraction (R-PP2) together constitute at least 95%, more preferably at least 97%, most preferably at least 98% of the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0058] In addition to the first propylene-ethylene random copolymer fraction (R-PP1) and the second propylene-ethylene random copolymer fraction (R-PP2), the single-phase propylene-ethylene random copolymer composition (R-PP) may contain other additives known in the art; however, these remainders should not exceed 5.0 wt.%, preferably not more than 3.0 wt.%, for example not more than 2.0 wt.% of the single-phase propylene-ethylene random copolymer composition (R-PP). For example, the single-phase propylene-ethylene random copolymer composition (R-PP) may additionally contain small amounts of additives (A) selected from antioxidants, stabilizers, fillers, colorants, nucleating agents and antistatic agents. Generally speaking, these additives can be incorporated during the compounding of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0059] In a specific embodiment, the single-phase propylene-ethylene random copolymer composition (R-PP) consists of a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2) and optional additives (A).

[0060] If the single-phase propylene-ethylene random copolymer composition (R-PP) of the unimodal or bimodal embodiment comprises an α-nucleating agent, it is preferably free of β-nucleating agents. The α-nucleating agent is preferably selected from the following:

[0061] (i) salts of mono- and polycarboxylic acids, for example sodium benzoate or aluminum tert-butylbenzoate, and

[0062] (ii) dibenzylidene sorbitol (e.g. 1,3:2,4-dibenzylidene sorbitol) and C1-C8 alkyl-substituted dibenzylidene sorbitol derivatives, such as methyldibenzylidene sorbitol, ethyldibenzylidene sorbitol or dimethyldibenzylidene sorbitol (e.g. 1,3:2,4-di(methylbenzylidene)sorbitol), or substituted nonitol derivatives, such as 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol, and

[0063] (iii) salts of phosphoric acid diesters, such as sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate or hydroxy-bis[2,2'-methylene-bis(4,6-di-tert-butylphenyl)aluminum phosphate], and

[0064] (iv) vinylcycloalkane polymers and vinylalkane polymers (discussed in detail below), and

[0065] (v) mixtures thereof.

[0066] These additives are generally commercially available and are described, for example, in Hans Zweifel's "Plastic Additives Handbook", 5th edition, 2001, pages 871 to 873.

[0067] It is to be understood that the amount of additive (A) relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP) includes any carrier polymer, i.e. a masterbatch carrier polymer, used to introduce the additive into the single-phase propylene-ethylene random copolymer composition (R-PP). An example of such a carrier polymer is a polypropylene homopolymer in powder form.

[0068] First propylene-ethylene random copolymer portion (R-PP1)

[0069] The first propylene-ethylene random copolymer fraction (R-PP1) is a copolymer of propylene and ethylene.

[0070] The first propylene-ethylene random copolymer fraction (R-PP1) is obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is preferably in the range of 0.6 to 4.5 mol%, more preferably in the range of 0.8 to 3.6 mol%, most preferably in the range of 1.0 to 3.0 mol%.

[0071] The melt flow rate (MFR2) of the first propylene-ethylene random copolymer part (R-PP1) measured at 230°C under a load of 2.16 kg according to ISO 1133 is preferably in the range of 0.01 to 4.0 g / 10 min, more preferably in the range of 0.1 to 2.0 g / 10 min, most preferably in the range of 0.2 to 1.0 g / 10 min.

[0072] The single-phase propylene-ethylene random copolymer composition (R-PP) may be bimodal in terms of molecular weight (as indicated by the value of the melt flow rate). Thus, the ratio of the melt flow rate (MFR2) of the single-phase propylene-ethylene random copolymer composition (R-PP) to the melt flow rate (MFR2) of the first propylene-ethylene random copolymer fraction (R-PP1) (both measured according to ISO 1133 at 230°C under a load of 2.16 kg and expressed in g / 10 min), [MFR(R-PP)] / [MFR(R-PP1)], is preferably from 0.20 to 1.00, more preferably from 0.25 to 0.75, most preferably from 0.33 to 0.50.

[0073] Additionally or alternatively, the single-phase propylene-ethylene random copolymer composition (R-PP) may be bimodal with respect to the ethylene content. Thus, the ratio of the ethylene content of the single-phase propylene-ethylene random copolymer composition (R-PP) to the ethylene content of the first propylene-ethylene random copolymer fraction (R-PP1) (both determined by quantitative 13 C-NMR spectroscopy and expressed in mol %), i.e., [C2(R-PP)] / [C2(R-PP1)] is in the range of 1.00 to 3.00, more preferably in the range of 1.10 to 2.50, and most preferably in the range of 1.20 to 2.00.

[0074] Second propylene-ethylene random copolymer portion (R-PP2)

[0075] The second propylene-ethylene random copolymer fraction (R-PP2) is a copolymer of propylene and ethylene.

[0076] The second propylene-ethylene random copolymer fraction (R-PP2) is obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is preferably in the range of 0.9 to 9.0 mol%, more preferably in the range of 1.5 to 8.0 mol%, most preferably in the range of 3.0 to 7.0 mol%.

[0077] The melt flow rate (MFR2) of the second propylene-ethylene random copolymer part (R-PP2) measured at 230°C under a load of 2.16 kg according to ISO 1133 is preferably in the range of 0.01 to 1.00 g / 10 min, more preferably in the range of 0.02 to 0.50 g / 10 min, most preferably in the range of 0.03 to 0.30 g / 10 min.

[0078] method

[0079] In a second aspect, the present invention relates to a method for obtaining the single-phase propylene-ethylene random copolymer composition (R-PP) according to the first aspect, the method comprising the following steps:

[0080] a) polymerizing propylene and ethylene comonomer units in the presence of a single site catalyst in a first polymerization reactor to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and the single site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor;

[0081] b) removing the first polymerization mixture from the first polymerization reactor, optionally performing steps c1) to c3), and then performing step d);

[0082] c1) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor;

[0083] c2) polymerizing propylene and ethylene comonomer units in the presence of the single site catalyst in the second polymerization reactor to produce a second polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2), and the single site catalyst;

[0084] c3) removing the second polymerization mixture from the second polymerization reactor; and

[0085] d) compounding the first polymerization mixture if steps c1) to c3) are absent, or the second polymerization mixture if steps c1) to c3) are present, optionally adding additive (A).

[0086] If the single-phase propylene-ethylene random copolymer composition (R-PP) is a unimodal single-phase propylene-ethylene random copolymer composition, steps c1) to c3) are absent, which means that the process comprises the following steps:

[0087] a) polymerizing propylene and ethylene comonomer units in the presence of a single site catalyst in a first polymerization reactor to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and the single site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor;

[0088] b) removing the first polymerization mixture from the first polymerization reactor; and

[0089] d) compounding the first polymerization mixture, optionally adding additives (A).

[0090] In case the monophasic propylene-ethylene random copolymer composition (R-PP) is a bimodal monophasic propylene-ethylene random copolymer composition, steps c1) to c3) are present, which means that the process comprises the following steps:

[0091] a) polymerizing propylene and ethylene comonomer units in the presence of a single site catalyst in a first polymerization reactor to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and the single site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor;

[0092] b) removing the first polymerization mixture from the first polymerization reactor;

[0093] c1) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor;

[0094] c2) polymerizing propylene and ethylene comonomer units in the presence of the single site catalyst in the second polymerization reactor to produce a second polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2), and the single site catalyst;

[0095] c3) removing the second polymerization mixture from the second polymerization reactor; and

[0096] d) compounding the second polymerization mixture, optionally adding additives (A).

[0097] The operating temperature in the first polymerization reactor (R1) is preferably in the range of 60 to 85°C, more preferably in the range of 62 to 80°C, more preferably in the range of 65 to 75°C.

[0098] As an alternative or in addition to the previous paragraph, preferably the operating temperature in the second polymerization reactor (R2), if present, is in the range of 70 to 95 °C, more preferably in the range of 73 to 85 °C.

[0099] Typically, the pressure in the first polymerization reactor (R1), preferably the loop reactor (LR), is from 20 to 80 bar, preferably from 30 to 70 bar, e.g. from 35 to 65 bar, and the pressure in the second polymerization reactor (R2), the gas phase reactor (GPR), is from 5 to 50 bar, preferably from 15 to 40 bar.

[0100] Preferably, hydrogen is added to each polymerization reactor to control the molecular weight, ie the melt flow rate MFR2.

[0101] In addition to the (main) polymerization of the propylene-ethylene random copolymer in the polymerization reactors (R1 and optionally R2), the preparation of the propylene-ethylene random copolymer may also comprise a preceding prepolymerization in a prepolymerization reactor (PR) upstream of the first polymerization reactor (R1).

[0102] Polypropylene (Pre-PP) is produced in a prepolymerization reactor (PR). The prepolymerization is carried out in the presence of a single-site catalyst (SSC). According to this embodiment, the single-site catalyst is introduced into the prepolymerization step. However, this should not exclude the option of adding other cocatalysts during the polymerization process (e.g., at a later stage), for example in the first reactor (R1). In one embodiment, if prepolymerization is used, all components of the single-site catalyst are added only in the prepolymerization reactor (PR).

[0103] The prepolymerization reaction is usually carried out at a temperature of 0 to 60°C, preferably 15 to 50°C, more preferably 18 to 45°C.

[0104] The pressure in the prepolymerisation reactor is not critical but must be high enough to keep the reaction mixture in the liquid phase. Thus, the pressure may be from 20 to 100 bar, for example from 30 to 70 bar.

[0105] In a preferred embodiment the prepolymerisation is carried out as bulk slurry polymerisation in liquid propylene, ie the liquid phase comprises mainly propylene and optionally inert components dissolved therein. Furthermore, according to the present invention an ethylene feed is used in the prepolymerisation process as described above.

[0106] Other components may also be added to the prepolymerization stage. Thus, as is known in the art, hydrogen may be added to the prepolymerization stage to control the molecular weight of the polypropylene (Pre-PP). In addition, antistatic additives may be used to prevent particles from adhering to each other or to the walls of the reactor.

[0107] The precise control of the prepolymerization conditions and reaction parameters is within the skill of those skilled in the art.

[0108] Due to the above-defined process conditions during the prepolymerization, a mixture (MI) of the single-site catalyst (SSC) produced in the prepolymerization reactor (PR) and the polypropylene (Pre-PP) is preferably obtained. Preferably, the single-site catalyst (SSC) is (finely) dispersed in the polypropylene (Pre-PP). In other words, the single-site catalyst (SSC) particles introduced into the prepolymerization reactor (PR) are broken into smaller fragments, which are evenly distributed in the growing polypropylene (Pre-PP). The size of the introduced single-site catalyst (SSC) particles and the resulting fragments is not critical to the present invention and is within the knowledge of a person skilled in the art.

[0109] As described above, if prepolymerization is used, the mixture (MI) of single site catalyst (SSC) and polypropylene (Pre-PP) produced in the prepolymerization reactor (PR) is transferred to the first reactor (R1) after said prepolymerization. Typically, the total amount of polypropylene (Pre-PP) in the final bimodal propylene-ethylene copolymer (R-PP) is quite low, typically not exceeding 5.0 wt.-%, more preferably not exceeding 4.0 wt.-%, still more preferably in the range of 0.5 to 4.0 wt.-%, for example in the range of 1.0 to 3.0 wt.-%.

[0110] If no prepolymerization is used, propylene and other ingredients, such as single site catalyst (SSC), are introduced directly into the first polymerization reactor (R1).

[0111] In one embodiment, the present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP) as described above, obtainable by, more preferably by, the process described herein. All preferred embodiments and alternatives given above and below for the single-phase propylene-ethylene random copolymer composition (R-PP) apply mutatis mutandis to the single-phase propylene-ethylene random copolymer composition (R-PP) obtainable / obtained by the present process.

[0112] Catalytic system

[0113] The single-site catalyst of the present invention can be any supported metallocene catalyst suitable for producing isotactic polypropylene.

[0114] The single site catalyst (SSC) preferably comprises a metallocene complex, a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and a silica support.

[0115] In particular, the single site catalyst (SSC) preferably comprises:

[0116] (i) Metallocene complex of general formula (I)

[0117]

[0118] Wherein, each X is independently a σ (sigma) donor ligand,

[0119] L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R' is independently a hydrogen atom or a C1-C 20 Hydrocarbyl, the C1-C 20 The hydrocarbon group may optionally contain one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements or fluorine atoms, or alternatively, two R' groups may be taken together to form a ring,

[0120] Each R 1 are independently the same or may be different and are hydrogen, linear or branched C1-C6 alkyl, C 7-20 Arylalkyl, C 7-20 Alkyl aryl, C 6-20 Aryl or OY group, wherein Y is C 1-10 hydrocarbon group, and optionally, two adjacent R 1 The groups may be part of a ring including the phenyl carbon to which they are bonded,

[0121] Each R 2 are independently the same or may be different and are CH2-R 8 group, where R 8 H, straight or branched C 1-6 Alkyl, C 3-8 Cycloalkyl or C 6-10 Aryl,

[0122] R 3 is a straight or branched C1-C6 alkyl group, C 7-20 Arylalkyl, C 7-20 Alkyl aryl or C6-C 20 Aryl,

[0123] R 4 C(R 9 )3 groups, wherein R 9 is a linear or branched C1-C6 alkyl group,

[0124] R 5 is hydrogen or an aliphatic C1-C 20 Hydrocarbyl, the aliphatic C1-C 20 The hydrocarbon group may optionally contain one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements;

[0125] R 6 is hydrogen or an aliphatic C1-C 20 Hydrocarbyl, the aliphatic C1-C 20 The hydrocarbyl group optionally contains one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements; or

[0126] R 5 and R 6 can form a 5-membered saturated carbocyclic ring, which is optionally substituted by n R 10 Group substitution, n is 0 to 4;

[0127] Each R 10 Same or different, and can be C1-C 20 A hydrocarbon group or a C1-C ...20 hydrocarbon group;

[0128] R 7 is H, a linear or branched C1-C6 alkyl group or an aryl or heteroaryl group having 6 to 20 carbon atoms, the aryl or heteroaryl group being optionally substituted by one to three R 11 Group substitution,

[0129] Each R 11 are independently the same or may be different and are hydrogen, linear or branched C1-C6 alkyl, C 7-20 Arylalkyl, C 7-20 Alkyl aryl, C 6-20 Aryl or OY group, wherein Y is C 1-10 Hydrocarbon group,

[0130] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0131] (iii) Silica support.

[0132] The term "σ-donor ligand" is well known to those skilled in the art, i.e., a group that binds to the metal via a σ bond. Thus, the anionic ligand "X" can independently be a halogen or selected from the group consisting of R', OR', SiR'3, OSiR'3, OSO2CF3, OCOR', SR', NR'2 or PR'2, wherein R' is independently hydrogen, a linear or branched, cyclic or acyclic C1 to C 20 Alkyl, C2 to C 20 Alkenyl, C2 to C 20 Alkynyl, C3 to C 12 Cycloalkyl, C6 to C 20 Aryl, C7 to C 20 Arylalkyl, C7 to C 20 Alkyl aryl, C8 to C 20 Arylalkenyl, wherein the R' group may optionally contain one or more heteroatoms belonging to Groups 14 to 16. In a preferred embodiment, the anionic ligands "X" are identical and are halogen (eg, Cl), methyl, or benzyl.

[0133] Preferred monovalent anionic ligands are halogens, especially chloride (Cl).

[0134] More preferably, the metallocene catalyst has formula (Ia)

[0135]

[0136] In the formula, each R 1 are independently the same or different and are hydrogen, linear or branched C1-C6 alkyl, wherein at least one R of each phenyl group1 Not hydrogen,

[0137] R' is C1-C 10 a hydrocarbon group, preferably a C1-C4 hydrocarbon group, more preferably a methyl group, and

[0138] X is independently a hydrogen atom, a halogen atom, a C1-C6 alkoxy group, a C1-C6 alkyl group, a phenyl group or a benzyl group.

[0139] Most preferably, X is chlorine, benzyl or methyl. The two X groups are preferably the same. The most preferred options are two chlorines, two methyls or two benzyls, especially two chlorines.

[0140] Preferred complexes of metallocene catalysts include:

[0141] Racemic-dimethylsilanediylbis[2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0142] Racemic-trans-dimethylsilanediyl[2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl][2-methyl-4-(4'-tert-butylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0143] Racemic-trans-dimethylsilanediyl[2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl][2-methyl-4-phenyl-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0144] Racemic-trans-dimethylsilanediyl[2-methyl-4-(3',5'-tert-butylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0145] Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(4'-tert-butylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0146] Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride,

[0147] Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-5-di-tert-butyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride.

[0148] Particularly preferred is rac-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride.

[0149] The ligands required to form the complexes and catalysts of the present invention can be synthesized by any method, and a skilled organic chemist can devise a variety of synthetic schemes to produce the necessary ligand materials. For example, WO 2007 / 116034 discloses the necessary chemical reactions. Synthetic schemes are generally also found in WO 2002 / 02576, WO 2011 / 135004, WO 2012 / 084961, WO 2012 / 001052, WO 2011 / 076780, WO 2015 / 158790 and WO 2018 / 122134. With particular reference to WO 2019 / 179959, the most preferred catalysts of the present invention are described.

[0150] co-catalyst

[0151] In order to form an active catalytic species, it is generally necessary to use a co-catalyst as is well known in the art.

[0152] According to the present invention, an aluminoxane cocatalyst may be used in combination with the metallocene catalyst complex as defined above.

[0153] The aluminoxane cocatalyst may be one of formula (II):

[0154]

[0155] In the formula, n is usually 6 to 20, and R has the following meanings.

[0156] Aluminoxanes are formed by partial hydrolysis of organoaluminum compounds, such as aluminoxanes of the formula AlR3, AlR2Y, and Al2R3Y3, where R can be, for example, C1-C 10 Alkyl, preferably C1-C5 alkyl, or C3-C 10 Cycloalkyl, C7-C 12 Arylalkyl or alkylaryl and / or phenyl or naphthyl, wherein Y can be hydrogen, halogen, preferably chlorine or bromine, or C1-C 10Alkoxy, preferably methoxy or ethoxy. The oxygen-containing aluminoxane obtained is usually not a pure compound but a mixture of oligomers of the formula (II).

[0157] The preferred aluminoxane is methylaluminoxane (MAO).Since the aluminoxanes used as cocatalysts in the present invention are not pure compounds (due to the way they are prepared), the molar concentrations of the aluminoxane solutions below are based on their aluminum content.

[0158] According to the present invention, a boron-containing cocatalyst may also be used instead of the aluminoxane cocatalyst, or the aluminoxane cocatalyst may be used in combination with the boron-containing cocatalyst.

[0159] It will be appreciated by those skilled in the art that when a boron-based cocatalyst is used, the complex is typically pre-alkylated by reaction with an alkyl aluminum compound, such as TIBA. This process is well known and any suitable aluminum alkyl, such as Al(C1-C6 alkyl)3, may be used. Preferred aluminum alkyl compounds are triethylaluminum, triisobutylaluminum, triisohexylaluminum, tri-n-octylaluminum, and triisooctylaluminum.

[0160] Alternatively, when a borate cocatalyst is used, the metallocene catalyst complex is in its alkylated form, ie, for example, a dimethyl or dibenzyl metallocene catalyst complex may be used.

[0161] The target boron-based co-catalysts include boron-based co-catalysts of formula (III)

[0162] BY3(III)

[0163] In the formula, Y is the same or different and is a hydrogen atom, an alkyl group having 1 to about 20 carbon atoms, an aryl group having 6 to about 15 carbon atoms, an alkylaryl group in which each alkyl group has 1 to 10 carbon atoms and the aryl group has 6 to 20 carbon atoms, an arylalkyl group, a haloalkyl group, or a haloaryl group, or fluorine, chlorine, bromine, or iodine. Preferred examples of Y are methyl, propyl, isopropyl, isobutyl, or trifluoromethyl, unsaturated groups such as aryl or haloaryl groups, such as phenyl, tolyl, benzyl, p-fluorophenyl, 3,5-difluorophenyl, pentachlorophenyl, pentafluorophenyl, 3,4,5-trifluorophenyl, and 3,5-bis(trifluoromethyl)phenyl. Preferred options are trifluoroborane, triphenylborane, tri(4-fluorophenyl)borane, tri(3,5-difluorophenyl)borane, tri(4-fluoromethylphenyl)borane, tri(2,4,6-trifluorophenyl)borane, tri(penta-fluorophenyl)borane, tri(tolyl)borane, tri(3,5-dimethyl-phenyl)borane, tri(3,5-difluorophenyl)borane and / or tri(3,4,5-trifluorophenyl)borane.

[0164] Tris(pentafluorophenyl)borane is particularly preferred.

[0165] However, preference is given to using borates, i.e. compounds containing a 3+ borate ion. The ionic promoter preferably contains a non-coordinating anion, such as tetrakis(pentafluorophenyl)borate and tetraphenylborate. Suitable counterions are protonated amines or aniline derivatives, such as methylammonium, aniline, dimethylammonium, diethylammonium, N-methylaniline, diphenylamine, N,N-dimethylaniline, trimethylammonium, triethylammonium, tri-n-butylammonium, methyldiphenylammonium, pyridine, p-bromo-N,N-dimethylaniline or p-nitro-N,N-dimethylaniline.

[0166] Preferred ionic compounds that can be used according to the present invention include:

[0167] Triethylammonium tetra(phenyl)borate,

[0168] Tributylammonium tetra(phenyl)borate,

[0169] Trimethylammonium tetra(tolyl)borate,

[0170] Tributylammonium tetra(tolyl)borate,

[0171] Tributylammonium tetrakis(pentafluorophenyl)borate,

[0172] Tripropylammonium tetrakis(dimethylphenyl)borate,

[0173] Tributylammonium tetrakis(trifluoromethylphenyl)borate,

[0174] Tributylammonium tetrakis(4-fluorophenyl)borate,

[0175] N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate,

[0176] N,N-dimethylbenzylammonium tetrakis(pentafluorophenyl)borate,

[0177] N,N-dimethylanilinium tetrakis(phenyl)borate,

[0178] N,N-diethylanilinium tetra(phenyl)borate,

[0179] N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,

[0180] N,N-di(propyl)ammonium tetrakis(pentafluorophenyl)borate,

[0181] Di(cyclohexyl)ammonium tetrakis(pentafluorophenyl)borate,

[0182] triphenylphosphine tetra(phenyl)borate,

[0183] Triethylphosphine tetra(phenyl)borate,

[0184] Diphenylphosphine tetrakis(phenyl)borate,

[0185] tri(methylphenyl)phosphine tetra(phenyl)borate,

[0186] tris(dimethylphenyl)phosphine tetra(phenyl)borate,

[0187] triphenylcarbonium tetrakis(pentafluorophenyl)borate,

[0188] or ferrocenium tetrakis(pentafluorophenyl)borate.

[0189] Preferred are triphenylcarbonium tetrakis(pentafluorophenyl)borate,

[0190] N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate or

[0191] N,N-Dimethylbenzylammonium tetrakis(pentafluorophenyl)borate.

[0192] Surprisingly, it has been found that certain boron co-catalysts are particularly preferred. Therefore, preferred borates for use in the present invention include trityl ions. Therefore, N,N-dimethylammonium-tetrakispentafluorophenylborate, Ph3CB(PhF5)4 and their analogs are particularly preferred.

[0193] According to the present invention, preferred cocatalysts are aluminoxanes, more preferably methylaluminoxane, combinations of aluminoxanes with Al-alkyl groups, boron or borate cocatalysts, and combinations of aluminoxanes with boron-based cocatalysts.

[0194] Suitable amounts of cocatalysts are well known to those skilled in the art.The molar ratio of boron to metal ion of the metallocene may be in the range of 0.5:1 to 10:1 mol / mol, preferably 1:1 to 10:1, in particular 1:1 to 5:1 mol / mol.

[0195] The molar ratio of aluminum in the aluminoxane to the metal ion of the metallocene may be in the range of 1:1 to 2000:1 mol / mol, preferably in the range of 10:1 to 1000:1, more preferably in the range of 50:1 to 500:1 mol / mol.

[0196] The catalyst can be used in a supported or unsupported form, preferably in a supported form. The particulate support material used is preferably an organic or inorganic material, such as silicon dioxide, aluminum oxide, zirconium oxide or a mixed oxide (e.g., silicon dioxide-aluminum oxide), with silicon dioxide, aluminum oxide or silicon dioxide-aluminum oxide being particularly preferred. Silica support is preferably used. Those skilled in the art are aware of the steps required to support the metallocene catalyst.

[0197] Particularly preferably, the support is a porous material so that the complex can be loaded into the pores of the support, for example using methods similar to those described in WO 94 / 14856 (Mobil), WO 95 / 12622 (Borealis) and WO 2006 / 097497.

[0198] The average particle size of the silica support can generally be from 10 to 100 μm. However, it has proven to be particularly advantageous if the support has a median particle size d50 of from 15 to 80 μm, preferably from 18 to 50 μm.

[0199] The silica support may have an average pore size in the range of 10 to 100 nm and a pore volume of 1 to 3 mL / g.

[0200] Examples of suitable support materials are silicas such as ES757 produced and sold by PQ, Sylopol 948 produced and sold by Grace or SUNSPERA DM-L-303 produced by AGC Si Technologies. The support can optionally be calcined before use in the catalyst preparation to achieve an optimal silanol group content.

[0201] The use of these vectors is routine in the art.

[0202] In a particularly preferred embodiment, the catalyst system corresponds to ICS3 or CCS4 of WO 2020 / 239602 A1.

[0203] Products

[0204] In a final aspect, the present invention relates to an article comprising a single-phase propylene-ethylene random copolymer composition (R-PP) in an amount of at least 75 wt%, more preferably at least 90 wt%, most preferably at least 95 wt%.

[0205] In a particular embodiment, the article consists of a single-phase propylene-ethylene random copolymer composition (R-PP).

[0206] Particularly preferably, the article is a pipe.

[0207] The pipe preferably has a pipe pressure test stability according to ISO 1167-1 and ISO 1167-2 (20°C, 16 MPa) of at least 20 hours, more preferably at least 30 hours, most preferably at least 40 hours.

[0208] Additionally or alternatively, the pipeline preferably has a pipeline pressure test stability according to ISO 1167-1 and ISO 1167-2 (95°C, 4.6 MPa) of at least 200 h, more preferably at least 1000 h, most preferably at least 5000 h.

[0209] Example

[0210] A. Measurement Method

[0211] Unless otherwise defined, the following definitions of terms and determination methods apply to the general embodiments of the present invention as described above, including the claims, and the following examples.

[0212] Quantification of microstructure by NMR spectroscopy

[0213] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the isotacticity and regioregularity of the polymers.

[0214] The Bruker Advance III 400 NMR spectrometer was used to analyze 1 H and 13 C were operated at 400.15 and 100.62 MHz, respectively, and quantitative data were recorded in solution. 13 C{ 1 H}NMR spectroscopy. All spectra were obtained using 13 A C-optimized 10 mm extended temperature probe was used for recording at 125 °C, and nitrogen was used for all pneumatics.

[0215] For the polymers, approximately 200 mg of material was dissolved in 1,2-tetrachloroethane-d2 (TCE-d2). To ensure homogeneity of the solution, after initial sample preparation in a heating block, the NMR tube was further heated in a rotary oven for at least 1 hour. The tube was inserted into the magnet and rotated at 10 Hz. This setting was chosen primarily for the high resolution required for quantification of the tacticity distribution (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V.; Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromolecules 30 (1997) 6251). Standard single-pulse excitation was used with NOE and a two-stage WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289). A total of 8192 (8k) transients were collected for each spectrum.

[0216] Quantification was performed using a proprietary computer program 13 C{ 1 H} NMR spectra are processed, integrated, and the relevant quantitative properties are determined from the integration.

[0217] For propylene homopolymers, all chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

[0218] Characteristic signals corresponding to regio defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, HN, Macromolecules 17 (1984), 1950) or comonomers were observed.

[0219] The tacticity distribution was quantified by integrating the methyl region between 23.6 and 19.7 ppm, correcting for any sites not associated with the stereo sequence of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromolecules 30 (1997) 6251).

[0220] Specifically, the effects of regio defects and comonomers on the tacticity distribution quantification were corrected by subtracting representative regio defect and comonomer integrals from the specific integrated region of the stereo sequence.

[0221] Isotacticity is determined at the pentad level and is reported as the percentage of isotactic pentad (mmmm) sequences over all pentad sequences:

[0222] [mmmm]% = 100*(mmmm / sum of all quintuples)

[0223] The presence of 2,1-erythro regio defects is indicated by two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites. No characteristic signals corresponding to other types of regio defects were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0224] The amount of 2,1-erythro regiodefects was quantified using the average integral of two characteristic methyl sites at 17.7 and 17.2 ppm:

[0225] P 21e =(I e6 +I e8 ) / 2

[0226] The amount of 1,2-primarily inserted propene was quantified based on the methyl region, with corrections made for sites not relevant to the primary insertion included in this region and for primary insertion sites excluded from this region:

[0227] P 12 =I CH3 +P 12e

[0228] The total amount of propene is quantified as the sum of the primary inserted propene and all other regio defects present:

[0229] P 总 =P 12 +P 21e

[0230] The mole percentage of 2,1-erythro regio defects relative to all propylene was quantified:

[0231] [21e]mol-%=100*(P 21e / P 总 )

[0232] The method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) was used to 13 C{ 1 The comonomer fraction is quantified by integrating multiple signals across the entire spectral region of the H} spectrum. This method was chosen for its robustness and ability to account for the presence of regio defects when necessary. Slight adjustments to the integration region are made to improve applicability across the entire range of comonomer contents encountered.

[0233] For systems where only isolated ethylene is observed in the PPEPP sequence, the method of Wang et al. was modified to reduce the effect of nonzero integrals at sites known to be absent. This method reduces the overestimation of ethylene content in this system and does so by reducing the number of sites used to determine absolute ethylene content:

[0234] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0235] By using this set of sites, the corresponding integration formula becomes:

[0236] E=0.5(I H +I G +0.5(I C +I D ))

[0237] The same symbols are used as in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157). The formula for absolute propylene content is not modified.

[0238] Calculate the mole percentage of comonomer incorporation based on the mole fraction:

[0239] E[mol%]=100*fE

[0240] Calculate the weight percent of comonomer incorporation based on the mole fraction:

[0241] E[weight%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0242] The triad-level comonomer sequence distribution was determined using the analytical method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen for its robustness and for its applicability to a wider range of comonomer contents with slight adjustments to the integration region.

[0243] The relative amount of isolated ethylene incorporation relative to block ethylene incorporation was calculated from the triad sequence distribution using the following relationship (Formula (I)):

[0244]

[0245] Where,

[0246] I(E) is the relative content of isolated ethylene sequences and blocked ethylene sequences [in %];

[0247] fPEP is the mole fraction of propylene / ethylene / propylene sequences (PEP) in the sample;

[0248] fPEE is the mole fraction of propylene / ethylene / ethylene sequences (PEE) and ethylene / ethylene / propylene sequences (EEP) in the sample;

[0249] fEEE is the mole fraction of ethylene / ethylene / ethylene sequences (EEE) in the sample.

[0250] Calculate the comonomer content of the second propylene-ethylene random copolymer fraction (R-PP2):

[0251]

[0252] Where,

[0253] w(PP1) is the weight fraction [in wt. %] of the first propylene-ethylene random copolymer fraction (R-PP1),

[0254] w(PP2) is the weight fraction [in wt. %] of the second propylene-ethylene random copolymer fraction (R-PP2),

[0255] C(PP1) is the comonomer content in mol% of the first propylene-ethylene random copolymer fraction (R-PP1), C(PP) is the comonomer content in mol% of the single-phase propylene-ethylene random copolymer composition (R-PP),

[0256] C(PP2) is the calculated comonomer content of the second propylene-ethylene random copolymer fraction (R-PP2) [in mol %].

[0257] Melt flow rate

[0258] The melt flow rate (MFR) is measured according to ISO 1133 and is expressed in g / 10 min. The MFR is an indicator of the polymer's flowability and, therefore, its processability. The higher the melt flow rate, the lower the polymer's viscosity. The MFR2 of polypropylene is measured at a temperature of 230°C and a load of 2.16 kg.

[0259] Calculate the melt flow rate MFR2 (230°C) of the second propylene-ethylene random copolymer fraction (PP2):

[0260]

[0261] Where,

[0262] w(PP1) is the weight fraction [in wt. %] of the first propylene-ethylene random copolymer fraction (R-PP1),

[0263] w(PP2) is the weight fraction [in wt. %] of the second propylene-ethylene random copolymer fraction (R-PP2),

[0264] MFR(PP1) is the melt flow rate MFR2 (230°C) of the first propylene-ethylene random copolymer fraction (R-PP1) in g / 10 min,

[0265] MFR(PP) is the melt flow rate MFR2 (230°C) of the single-phase propylene-ethylene random copolymer composition (R-PP) in g / 10 min,

[0266] MFR(PP2) is the calculated melt flow rate MFR2 (230°C) of the second propylene-ethylene random copolymer fraction (R-PP2) [in g / 10 min].

[0267] Xylene soluble fraction at room temperature (XCS, wt. %): The amount of polymer soluble in xylene is determined at 25° C. according to ISO 16152 (5th edition, July 1, 2005).

[0268] Number average molecular weight (M n ), weight average molecular weight (M w ), size average molecular weight and molecular weight distribution (MWD)

[0269] The molecular weight averages (Mz, Mw, Mn) and molecular weight distribution (MWD), ie, Mz / Mw (where Mz is the size average molecular weight and Mw is the weight average molecular weight), were determined by gel permeation analysis.

[0270] Chromatography (GPC) was performed according to ISO 16014-4:2003 and ASTM D 6474-99.A.

[0271] A PolymerChar GPC instrument equipped with an infrared (IR) detector was used with Polymer Laboratories 3xOlexis and 1xOlexis guard columns, using 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methyl-phenol) as the solvent, at a temperature of 160°C and a constant flow rate of 1 mL / min. 200 μL of sample solution was injected for each analysis. The column set was calibrated using a universal calibration (according to ISO 16014-2:2003) using at least 15 narrow MWD polystyrene (PS) standards ranging from 0.5 kg / mol to 11,500 kg / mol. Mark Houwink constants for PS, PE, and PP were as described in ASTM D 6474-99. All samples were prepared by dissolving 5.0-9.0 mg of polymer in 8 mL (at 160°C) stabilized TCB (same as mobile phase) at up to 160°C with constant gentle shaking in the autosampler of the GPC instrument for 2.5 hours (for PP) and 3 hours (for PE).

[0272] DSC analysis, melting temperature (T m ) and heat of fusion (H f ), crystallization temperature (T c ) and heat of crystallization (H c ): Measurements were performed using a TA Instrument Q200 differential scanning calorimetry (DSC) on 5 to 7 mg samples. The DSC was run in the temperature range of -30 to +225°C according to ISO 11357 / Part 3 / Method C2 with a scan rate of 10°C / min in a heating / cooling / heating cycle. The crystallization temperature (T c ) and crystallization enthalpy (H c ) is determined during the cooling step, while the melting temperature (T m ) and melting enthalpy (H f ) is determined in the second heating step.

[0273] The glass transition temperature Tg was determined by dynamic mechanical analysis according to ISO 6721-7. The samples were compressed to form a 40×10×1 mm2 film at a heating rate of 2°C / min and a frequency of 1 Hz between -100°C and +150°C in torsion mode. 3 ) to complete the measurement.

[0274] Flexural modulus was measured according to ISO 178, Method A (3-point bend test) using 80 mm x 10 mm x 4 mm specimens. A test speed of 2 mm / min and a span length of 16 times the thickness were used, as per the standard. The test temperature was 23 ± 2°C. Injection molding was performed according to ISO 19069-2, with a melt temperature of 230°C for all materials, regardless of the material's melt flow rate.

[0275] Notched Impact Strength (NIS)

[0276] 80×10×4 mm prepared according to ISO 19069-2 at +23°C or -20°C according to ISO 179 1eA 3 The Charpy notched impact strength (NIS) was measured on injection molded rod test specimens at a melt temperature of 230°C for all materials, regardless of the material melt flow rate.

[0277] Pipeline pressure testing

[0278] Pipes made from the inventive and comparative compositions were tested for pressure testing performance according to ISO 1167-1 and ISO 1167-2. Pipes with a diameter of 32 mm and a wall thickness of 3 mm were produced on a conventional pipe extrusion line according to ISO 1167-2 and then subjected to a circumferential (hoop) stress of 16 MPa at 20°C (or 4.6 MPa at 95°C) in a water-water apparatus according to ISO 1167-1. The time to failure was recorded (in hours), with the time marked "still in operation" indicating that the time to failure had not yet been reached at the time of filing this patent application.

[0279] B. Examples

[0280] The metallocene complex used in the polymerization method of the inventive example is trans-dimethylsilanediyl[2-methyl-4,8-bis(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride, which is the same as MC-2 disclosed in WO 2019 / 179959 A1.

[0281] For Inventive Examples IE1 to IE3, the preparation method of the catalyst system is similar to Inventive Catalyst System 3 (ICS3) in WO 2020 / 239602 A1, while for Inventive Examples IE4 and IE5, the preparation method of the catalyst system is similar to Comparative Catalyst System 4 (CCS4) in WO 2020 / 239602 A1.

[0282] The catalyst used in CE2 is a transesterified Ziegler-Natta catalyst supported on magnesium chloride, prepared according to the steps of WO 92 / 19653, which is the same as catalyst a1) in WO 2012 / 171745 A1, while the catalyst used in CE3 is an emulsion Ziegler-Natta catalyst, which is the same as the catalyst used in the inventive example in WO 2016 / 066446 A1.

[0283] The catalyst used in CE2 has an internal donor based on phthalate, while the catalyst used in CE3 has an internal donor based on citraconate. Both catalysts use di(cyclopentyl)dimethoxysilane (D donor) as the external donor.

[0284] Inventive Examples IE1 to IE5 and Comparative Examples CE2 and CE3 were polymerised according to the conditions given in Table 1 (Note: the MFR2 and C2 contents given after reactor R2 are properties of the GPR fraction (i.e. R-PP2) and are calculated from the values ​​measured after the loop reactor (i.e. R-PP1) and in the final microparticles (i.e. R-PP), using the appropriate mixing rules as given in the determination methods).

[0285] CE1 is commercially available under the designation RA130E (available from Borealis AG), which is a unimodal propylene-ethylene random copolymer produced using a Ziegler-Natta catalyst.

[0286] Table 1: Polymerization conditions of the propylene-ethylene random copolymer of the present invention and the comparative propylene-ethylene random copolymer

[0287]

[0288] Table 2: Properties of the propylene-ethylene random copolymers of the present invention and comparative propylene-ethylene random copolymers

[0289]

[0290] As can be seen in Table 2, the melt flow rates of the inventive examples (SSC-catalyzed) are comparable to those of the comparative examples (ZN-catalyzed), while comparable ethylene content results in a significantly higher XCS content in the comparative examples (7 to 9 wt % compared to less than 1 wt %). This lower extractables content indicates that the inventive compositions are more suitable for pipe applications, particularly for transporting drinking water, as significantly less oligomers (and other extractables) leach into the water.

[0291] Pipes with a diameter of 32 mm and a wall thickness of 3 mm were produced according to ISO 1167-2 using the CE1, IE1 and IE5 compositions.

[0292] Table 3: Pipeline pressure test results using the propylene-ethylene random copolymer of the present invention and comparative propylene-ethylene random copolymers

[0293]

[0294] As can be seen in Table 3, the pipe pressure resistance values ​​of the inventive compositions far exceed those of the Ziegler-Natta catalyzed comparative compositions. Bimodal Example IE5 is further improved, with significantly superior performance relative to unimodal Example IE1.

Claims

1. A single-phase propylene-ethylene random copolymer composition (R-PP), wherein the single-phase propylene-ethylene random copolymer composition (R-PP) has: i) a melt flow rate (MFR2) in the range of 0.01 to 1.00 g / 10 min, measured at 230° C., 2.16 kg load according to ISO 1133; ii) Based on 13 an ethylene content (C2) in the range of 1.5 to 7.5 mol %, determined by C-NMR spectroscopy; iii) a melting temperature (Tm) in the range of 120 to 150° C. as determined by DSC analysis; iv) By quantitative 13 a 2,1-regio defect content in the range of 0.05 to 1.20 mol % as determined by C-NMR spectroscopy; and v) a molecular weight distribution (Mw / Mn) in the range of 2.00 to 5.00 as determined by gel permeation chromatography (GPC).

2. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 1, having a xylene cold soluble content (XCS) determined according to ISO 16152 in the range of 0.10 to 5.0 wt.-%.

3. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 1 or 2, having a crystallization temperature (Tc) in the range of 80 to 110°C as determined by DSC analysis.

4. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of the preceding claims, which is prepared according to ISO 178 using a 80×10×4 mm2 injection molded according to ISO 19069-2. 3 The flexural modulus determined for the test bars was in the range of 500 to 1500 MPa.

5. The propylene-ethylene random copolymer (RACO) according to any one of the preceding claims, wherein The propylene-ethylene random copolymer (RACO) was prepared at +23°C according to ISO 179 / 1eA using a 80×10×4 mm2 injection molded according to ISO 19069-2. 3 The Charpy notched impact strength (NIS) of the test bar is between 5.0 and 20.0 kJ / m 2 within the range.

6. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of the preceding claims, wherein The single-phase propylene-ethylene random copolymer composition (R-PP) comprises: i) 40 to 70 wt.-%, relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP), of a first propylene-ethylene random copolymer fraction (R-PP1), said first propylene-ethylene random copolymer fraction (R-PP1) being obtained by 13 an ethylene content (C2) in the range of 0.6 to 4.50 mol % as determined by C-NMR spectroscopy; and ii) 30 to 60 wt.-% of a second propylene-ethylene random copolymer fraction (R-PP2), relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP), said second propylene-ethylene random copolymer fraction (R-PP2) being obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is in the range of 0.9 to 9.0 mol%, The first propylene-ethylene random copolymer portion (R-PP1) and the second propylene-ethylene random copolymer portion (R-PP2) together account for at least 95 wt% of the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP).

7. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 6, wherein: The ratio of the ethylene content of the single-phase propylene-ethylene random copolymer composition (R-PP) to the ethylene content of the first propylene-ethylene random copolymer fraction (R-PP1), i.e. [C2(R-PP)] / [C2(R-PP1)], is in the range of 1.00 to 3.00, wherein the ethylene contents are quantitatively determined. 13 The content was determined by C-NMR spectroscopy and expressed in mol%.

8. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 6 or 7, wherein: The first propylene-ethylene random copolymer part (R-PP1) has a melt flow rate (MFR2) in the range of 0.01 to 4.0 g / 10 min, measured at 230° C. and 2.16 kg load according to ISO 1133; and / or The second propylene-ethylene random copolymer part (R-PP2) has a melt flow rate (MFR2) measured according to ISO 1133 at 230°C under a load of 2.16 kg in the range of 0.01 to 1.00 g / 10 min.

9. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 7 to 8, wherein: The ratio of the melt flow rate (MFR2) of the single-phase propylene-ethylene random copolymer composition (R-PP) to the melt flow rate (MFR2) of the first propylene-ethylene random copolymer part (R-PP1), i.e. [MFR(R-PP)] / [MFR(R-PP1)], is in the range of 0.20 to 1.00, and the melt flow rate (MFR2) is measured according to ISO 1133 at 230°C and 2.16 kg load and expressed in g / 10 min.

10. A process for obtaining a single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of the preceding claims, said process comprising the following steps: a) polymerizing propylene and ethylene comonomer units in the presence of a single site catalyst in a first polymerization reactor to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and a single site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor; b) removing the first polymerization mixture from the first polymerization reactor, optionally performing steps c1) to c3), and then performing step d); c1) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor; c2) polymerizing propylene and ethylene comonomer units in the presence of the single site catalyst in the second polymerization reactor to produce a second polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2) and the single site catalyst; c3) removing the second polymerization mixture from the second polymerization reactor; and d) compounding the first polymerization mixture if steps c1) to c3) are absent or the second polymerization mixture if steps c1) to c3) are present, optionally adding additive (A).

11. The method according to claim 10, wherein: The single-site catalyst comprises: (i) Metallocene complex of general formula (I) Wherein, each X is independently a σ donor ligand, L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R' is independently a hydrogen atom or a C1-C 20 Hydrocarbon, the C1-C 20 The hydrocarbon group may optionally contain one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements or fluorine atoms, or alternatively, two R' groups may be taken together to form a ring, Each R 1 are independently the same or may be different and are hydrogen, linear or branched C1-C6 alkyl, C 7-20 Arylalkyl, C 7-20 Alkyl aryl, C 6-20 Aryl or OY group, wherein Y is C 1-10 A hydrocarbon group, and optionally, two adjacent R 1 The groups may be part of a ring including the phenyl carbon to which they are bonded, Each R 2 are independently the same or may be different, and are CH2-R 8 Group, where R 8 H, straight or branched chain C 1-6 Alkyl, C 3-8 Cycloalkyl or C 6-10 Aryl, R 3 is a straight or branched C1-C6 alkyl group, C 7-20 Arylalkyl, C 7-20 Alkyl aryl or C6-C 20 Aryl, R 4 C(R 9 )3 groups, wherein R 9 is a linear or branched C1-C6 alkyl group, R 5 is hydrogen or an aliphatic C1-C 20 Hydrocarbyl, aliphatic C1-C 20 The hydrocarbon group may optionally contain one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements; R 6 is hydrogen or an aliphatic C1-C 20 Hydrocarbyl, aliphatic C1-C 20 The hydrocarbon group optionally contains one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements; or R 5 and R 6 can form a 5-membered saturated carbocyclic ring, which may be optionally substituted by n R 10 Group substitution, n is 0 to 4; Each R 10 Same or different, and can be C1-C 20 A hydrocarbon group or a C1-C ... 20 Hydrocarbon; R 7 is H, a linear or branched C1-C6 alkyl group, or an aryl or heteroaryl group having 6 to 20 carbon atoms, the aryl or heteroaryl group being optionally substituted by one to three R 11 Group substitution, Each R 11 are independently the same or may be different and are hydrogen, linear or branched C1-C6 alkyl, C 7-20 Arylalkyl, C 7-20 Alkyl aryl, C 6-20 Aryl or OY group, wherein Y is C 1-10 Hydrocarbon, (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and (iii) Silica support.

12. The method according to claim 10 or 11, wherein: The metallocene complex is selected from: Racemic-dimethylsilanediylbis[2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride, Racemic-trans-dimethylsilanediyl[2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl][2-methyl-4-(4'-tert-butylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride, Racemic-trans-dimethylsilanediyl[2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl][2-methyl-4-phenyl-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride, Racemic-trans-dimethylsilanediyl[2-methyl-4-(3',5'-tert-butylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride, Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(4'-tert-butylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride, rac-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride, and Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacene-1-yl][2-methyl-4-(3',5'-5-di-tert-butyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride.

13. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 9, wherein: The single-phase propylene-ethylene random copolymer composition (R-PP) is obtainable by, more preferably by, the process according to any one of claims 10 to 12.

14. An article comprising the single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 9 or 13 in an amount of at least 75 wt%.

15. The article of claim 14, which is a pipe having the following characteristics: Pipeline pressure test stability (20°C, 16 MPa) for at least 20 h according to ISO 1167-1 and ISO 1167-2, and / or Pipeline pressure test stability for at least 200h according to ISO 1167-1 and ISO 1167-2 (95°C, 4.6MPa).

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