Process for preparation of propylene-ethylene random copolymers for pipeline applications

Abstract

A process for the preparation of a single phase propylene-ethylene random copolymer composition (R-PP) having an MFR2 of 0.01 to 1.00 g / 10 min in at least two polymerization reactors using a specific single site catalyst.

Description

Technical Field

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

[0002] Polypropylene, especially propylene random copolymers, is a versatile synthetic polymer that combines beneficial mechanical properties with ideal processing properties. These beneficial properties make polypropylene used in films, automotive products, sanitary products and pipes.

[0003] Polypropylene has long been used in pipe production because of its excellent resistance to physical damage (at both high and low temperatures), corrosion and chemical leaching, and because 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., MFR2 below about 0.50 g / 10 min) to achieve the required mechanical properties. Many catalysts, especially single-site catalysts, are unable to achieve such high molecular weights regardless of the amount of hydrogen (i.e., molecular weight controller) used during the polymerization. Another problem stems from the sensitivity of single-site catalysts to hydrogen (i.e., molecular weight controller), which means 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 need 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 the comparative copolymer, but showing some limited improvements in pipe properties (e.g., impact test and resistance to internal pressure). However, it has similar disadvantages to the previous case.

[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 in turn increases the cost and complexity of producing the composition.

[0009] Although significant progress has been made in the field of polypropylene pipes, there is still a need for other compositions that meet the requirements of low extractables content and excellent mechanical properties, especially long-term compression resistance. Summary of the invention

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

[0011] In a first aspect, the present invention relates to a process for preparing a propylene-ethylene random copolymer (R-PP), wherein the 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 measured at 230° C. and 2.16 kg load according to ISO 1133, the process comprising the following steps:

[0012] 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;

[0013] b) removing the first polymerization mixture from the first polymerization reactor;

[0014] c) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor;

[0015] d) 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;

[0016] e) removing the second polymerization mixture from the second polymerization reactor; and

[0017] f) optionally, compounding a second polymerization mixture, preferably adding additive (A);

[0018] Wherein, the single-site catalyst comprises:

[0019] (i) Metallocene complex of general formula (I)

[0020]

[0021] Wherein, each X is independently a σ donor ligand,

[0022] 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,

[0023] 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,

[0024] 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,

[0025] 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,

[0026] R 4 C(R 9 )3 groups, wherein R 9 is a linear or branched C1-C6 alkyl group,

[0027] R 5 is hydrogen or an aliphatic C1-C 20 Hydrocarbyl, aliphatic C1-C 20The hydrocarbon group may optionally contain one or more heteroatoms from Groups 14 to 16 of the Periodic Table of Elements;

[0028] 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

[0029] 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;

[0030] Each R 10 Same or different, and can be C1-C 20 A hydrocarbon group or a C1-C ... 20 Hydrocarbon;

[0031] 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,

[0032] 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,

[0033] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0034] (iii) Silica support.

[0035] In a second aspect, the present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP) obtainable by the process of the first aspect, more preferably obtainable by the process of the first aspect.

[0036] In a last 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 second aspect.

[0037] definition

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein may 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 according to the definitions listed below.

[0039] Unless expressly stated otherwise, use of the terms "a", "an", etc. means more than one.

[0040] Unless otherwise stated, the following amounts are given as weight percent (wt %).

[0041] Propylene homopolymers are polymers consisting mainly of propylene monomer units. Due to impurities, especially 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.

[0042] The random propylene copolymer is a copolymer of propylene monomer units and comonomer units, wherein the comonomer units are preferably selected from ethylene and C4-C8 alpha-olefins, wherein the comonomer units are randomly distributed on the polymer chain. The random propylene copolymer may contain comonomer units of more than one comonomer having different amounts of carbon atoms.

[0043] In the context of the present invention, the term "propylene-ethylene random copolymer" means that no other comonomers than propylene and ethylene are present in the copolymer. Thus, terpolymers such as propylene-ethylene-1-hexene terpolymers are not included in this definition.

[0044] 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.

[0045] Bimodal polymers are polymers having a bimodal distribution of more than one property.The bimodal random propylene-ethylene copolymer 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

[0046] method

[0047] In a first aspect, the present invention relates to a process for preparing a propylene-ethylene random copolymer (R-PP), wherein the 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 measured at 230° C. and 2.16 kg load according to ISO 1133, the process comprising the following steps:

[0048] 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;

[0049] b) removing the first polymerization mixture from the first polymerization reactor;

[0050] c) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor;

[0051] d) 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;

[0052] e) removing the second polymerization mixture from the second polymerization reactor; and

[0053] f) Optionally, compounding a second polymerization mixture, preferably adding additive (A).

[0054] Wherein, the single-site catalyst comprises:

[0055] (i) Metallocene complex of general formula (I)

[0056]

[0057] Wherein, each X is independently a σ donor ligand,

[0058] 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,

[0059] Each R1 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,

[0060] 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,

[0061] 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,

[0062] R 4 C(R 9 )3 groups, wherein R 9 is a linear or branched C1-C6 alkyl group,

[0063] 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;

[0064] 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

[0065] 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;

[0066] Each R 10 Same or different, and can be C1-C 20 A hydrocarbon group or a C1-C ... 20 Hydrocarbon;

[0067] 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,

[0068] 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,

[0069] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0070] (iii) Silica support.

[0071] 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.

[0072] 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.

[0073] 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, for example 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.

[0074] Preferably, hydrogen is added in each polymerization reactor to control the molecular weight, ie the melt flow rate MFR2.

[0075] In addition to the (main) polymerization of the propylene-ethylene random copolymer in the polymerization reactors (R1 and R2), the preparation of the propylene-ethylene random copolymer may also include a previous prepolymerization in a prepolymerization reactor (PR) upstream of the first polymerization reactor (R1).

[0076] The 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 (e.g. in a later stage), for example in the first reactor (R1). In one embodiment, if prepolymerization is applied, all components of the single site catalyst are added only in the prepolymerization reactor (PR).

[0077] 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.

[0078] 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.

[0079] In a preferred embodiment the prepolymerization is carried out as bulk slurry polymerization 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 prepolymerization process as described above.

[0080] Other components may also be added to the prepolymerization stage. Thus, as 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.

[0081] The precise control of the prepolymerization conditions and reaction parameters is within the skill of those skilled in the art.

[0082] Due to the process conditions in the prepolymerization as defined above, preferably a mixture (MI) of the single site catalyst (SSC) produced in the prepolymerization reactor (PR) and the polypropylene (Pre-PP) is obtained. Preferably, the single site catalyst (SSC) is (finely) dispersed in the polypropylene (Pre-PP). In other words, the introduced single site catalyst (SSC) particles in 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 as well as of the obtained fragments are not critical for the present invention and are within the knowledge of a person skilled in the art.

[0083] As mentioned above, if a 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 rather low, typically not more than 5.0 wt.-%, more preferably not more than 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.-%.

[0084] If no prepolymerization is used, propylene and other ingredients, such as single site catalyst (SSC), are introduced directly into the first polymerization reactor (R1).

[0085] Catalytic system

[0086] Single Site Catalyst (SSC) contains:

[0087] (i) Metallocene complex of general formula (I)

[0088]

[0089] Wherein, each X is independently a σ donor ligand,

[0090] 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,

[0091] 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,

[0092] 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,

[0093] 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,

[0094] R 4 C(R 9 )3 groups, wherein R 9 is a linear or branched C1-C6 alkyl group,

[0095] 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;

[0096] 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

[0097] 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;

[0098] Each R 10 Same or different, and can be C1-C 20 A hydrocarbon group or a C1-C ... 20 Hydrocarbon;

[0099] 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,

[0100] 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,

[0101] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0102] (iii) Silica support.

[0103] 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 R', OR', SiR'3, OSiR'3, OSO2CF3, OCOR', SR', NR'2 or PR'2 groups, wherein R' is independently hydrogen, a linear or branched, cyclic or non-cyclic 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.

[0104] Preferred monovalent anionic ligands are halogens, especially chlorine (Cl).

[0105] More preferably, the metallocene catalyst has formula (Ia)

[0106]

[0107] 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 1 Not hydrogen,

[0108] R' is C1-C 10 A hydrocarbon group, preferably a C1-C4 hydrocarbon group, more preferably a methyl group, and

[0109] 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.

[0110] 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.

[0111] Preferred complexes of metallocene catalysts include:

[0112] Racemic-dimethylsilanediylbis[2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0113] 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,

[0114] 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,

[0115] 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,

[0116] 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,

[0117] 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,

[0118] 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.

[0119] 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.

[0120] 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 design a variety of synthesis schemes to make the necessary ligand materials. For example, WO2007 / 116034 discloses the necessary chemical reactions. Synthesis schemes can also be generally 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.

[0121] Catalyst

[0122] In order to form an active catalytic species, it is generally necessary to use a promoter which is well known in the art.

[0123] According to the present invention, an aluminoxane cocatalyst may be used in combination with the metallocene catalyst complex as defined above.

[0124] The aluminoxane cocatalyst may be one of formula (II):

[0125]

[0126] In the formula, n is usually 6 to 20, and R has the following meanings.

[0127] Aluminoxanes are formed by partial hydrolysis of organoaluminum compounds, such as aluminoxanes of the formula AlR3, AlR2Y, and Al2R3Y3, wherein 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 10 Alkoxy, preferably methoxy or ethoxy. The oxygen-containing aluminoxane obtained is usually not a pure compound but a mixture of oligomers of the formula (II).

[0128] 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.

[0129] 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.

[0130] It will be appreciated by those skilled in the art that when a boron-based cocatalyst is used, the complex is usually 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.

[0131] 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.

[0132] The target boron-based co-catalyst includes a boron-based co-catalyst of formula (III)

[0133] BY3(III)

[0134] 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 halogenated alkyl group or a halogenated aryl group, or fluorine, chlorine, bromine or iodine. Preferred examples of Y are methyl, propyl, isopropyl, isobutyl or trifluoromethyl, unsaturated groups such as aryl or halogenated aryl 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.

[0135] Tris(pentafluorophenyl)borane is particularly preferred.

[0136] However, preference is given to using borates, i.e. compounds containing 3+ borate ions. The ionic promoter preferably contains a non-coordinating anion, for example tetrakis(pentafluorophenyl)borate and tetraphenylborate. Suitable counterions are protonated amines or aniline derivatives, for example 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.

[0137] Preferred ionic compounds that can be used according to the present invention include:

[0138] Triethylammonium tetra(phenyl)borate,

[0139] Tributylammonium tetra(phenyl)borate,

[0140] Trimethylammonium tetra(tolyl)borate,

[0141] Tributylammonium tetra(tolyl)borate,

[0142] Tributylammonium tetrakis(pentafluorophenyl)borate,

[0143] Tripropylammonium tetrakis(dimethylphenyl)borate,

[0144] Tributylammonium tetrakis(trifluoromethylphenyl)borate,

[0145] Tributylammonium tetra(4-fluorophenyl)borate,

[0146] N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate,

[0147] N,N-dimethylbenzylammonium tetrakis(pentafluorophenyl)borate,

[0148] N,N-dimethylanilinium tetrakis(phenyl)borate,

[0149] N,N-Diethylaniline tetra(phenyl)borate,

[0150] N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,

[0151] N,N-di(propyl)ammonium tetrakis(pentafluorophenyl)borate,

[0152] Di(cyclohexyl)ammonium tetrakis(pentafluorophenyl)borate,

[0153] Triphenylphosphine tetra(phenyl)borate,

[0154] Triethylphosphine tetra(phenyl)borate,

[0155] Diphenylphosphine tetrakis(phenyl)borate,

[0156] Tri(methylphenyl)phosphine tetra(phenyl)borate,

[0157] Tris(dimethylphenyl)phosphine tetra(phenyl)borate,

[0158] Triphenylcarbonium tetrakis(pentafluorophenyl)borate,

[0159] Or ferrocenium tetrakis(pentafluorophenyl)borate.

[0160] Preferred are triphenylcarbonium tetrakis(pentafluorophenyl)borate,

[0161] N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate or

[0162] N,N-Dimethylbenzylammonium tetrakis(pentafluorophenyl)borate.

[0163] Surprisingly, it has been found that certain boron promoters are particularly preferred. Therefore, preferred borates for use in the present invention include trityl ions. Therefore, it is particularly preferred to use N,N-dimethylammonium-tetrapentafluorophenyl borate, Ph3CB(PhF5)4 and their analogs.

[0164] According to the present invention, preferred cocatalysts are aluminoxanes, more preferably methylaluminoxane, combinations of aluminoxanes with Al-alkyls, boron or borate cocatalysts, and combinations of aluminoxanes with boron-based cocatalysts.

[0165] Suitable amounts of cocatalysts are well known to those skilled in the art.The molar ratio of boron to metal ions of the metallocene may be in the range of 0.5:1 to 10:1 mol / mol, preferably in the range of 1:1 to 10:1, in particular 1:1 to 5:1 mol / mol.

[0166] 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, and more preferably in the range of 50:1 to 500:1 mol / mol.

[0167] The catalyst can be used in a supported or non-supported form, preferably in a supported form. The particle support material used is preferably an organic or inorganic material, such as silicon dioxide, aluminum oxide, zirconium oxide or a mixed oxide (such as silicon dioxide-alumina), particularly preferably silicon dioxide, aluminum oxide or silicon dioxide-alumina. Preferably, a silicon dioxide support is used. Those skilled in the art know the steps required for supporting the metallocene catalyst.

[0168] 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 WO94 / 14856 (Mobil), WO95 / 12622 (Borealis) and WO2006 / 097497.

[0169] 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.

[0170] The average pore size of the silica support may be in the range of 10 to 100 nm, and the pore volume is 1 to 3 mL / g.

[0171] 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 may optionally be calcined before use in the catalyst preparation in order to achieve an optimal silanol group content.

[0172] The use of these vectors is routine in the art.

[0173] In a particularly preferred embodiment, the catalyst system corresponds to ICS3 or CCS4 of WO 2020 / 239602 A1.

[0174] Single-phase propylene-ethylene random copolymer composition (R-PP)

[0175] The process of the first aspect necessarily produces a single-phase propylene-ethylene random copolymer composition (R-PP).

[0176] 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, measured according to ISO 1133 at 230°C under a load of 2.16 kg. 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, measured according to ISO 1133 at 230°C under a load of 2.16 kg.

[0177] The single-phase propylene-ethylene random copolymer composition (R-PP) is prepared by 13 The ethylene content (C2) determined by C-NMR spectroscopy is preferably 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%.

[0178] The melting temperature (Tm) of the single-phase propylene-ethylene random copolymer composition (R-PP) determined by DSC analysis is preferably 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.

[0179] 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 preferably 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.

[0180] The single-phase propylene-ethylene random copolymer composition (R-PP) preferably has a xylene cold soluble content (XCS) 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.-%, as determined according to ISO 16152. Particularly preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) preferably has a xylene cold soluble content (XCS) 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.-%, as determined according to ISO 16152.

[0181] The crystallization temperature (Tc) of the single-phase propylene-ethylene random copolymer composition (R-PP) determined according to 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.

[0182] 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.

[0183] The term "2,1 regio defect" used in the present invention is defined as the sum of 2,1 erythro regio defect and 2,1 threo regio defect.

[0184] 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).

[0185] Accordingly, 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.

[0186] The single-phase propylene-ethylene random copolymer composition (R-PP) was quantitatively 13The 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 %.

[0187] The content of 2,1-regio defects may depend on the amount of comonomer, with higher amounts of comonomer generally being associated with lower contents of 2,1-regio defects.

[0188] The content of 2,1-regio defects may also depend on the polymerization temperature, with higher temperatures generally being associated with lower contents of 2,1-regio defects.

[0189] 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.

[0190] The single-phase propylene-ethylene random copolymer composition (R-PP) was prepared according to ISO 178 using a 80x10x4 mm 200 mm plastic injection molded according to ISO 19069-2. 3 The flexural modulus measured on the test bar 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.

[0191] The single-phase propylene-ethylene random copolymer composition (R-PP) was prepared at +23°C according to ISO 179 / 1eA using 80x10x4 mm injection molded according to ISO 19069-2. 3 The Charpy notched impact strength (NIS) measured by the test bar is preferably between 5.0 and 20.0 kJ / m 2 In the range of 7.0 to 15.0 kJ / m 2 The range is preferably between 8.0 and 12.0 kJ / m 2 Particularly preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) is molded at +23°C according to ISO 179 / 1eA using a 80x10x4 mm 3 The Charpy notched impact strength (NIS) measured by the test bar is preferably between 7.0 and 20.0 kJ / m 2 In the range of 8.0 to 20.0 kJ / m 2 within the range.

[0192] The single-phase propylene-ethylene random copolymer composition (R-PP) preferably comprises 40 to 70 wt.-% of the first propylene-ethylene random copolymer fraction (R-PP1) and 30 to 60 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).

[0193] More preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) comprises 45 to 65 wt.-% of the first propylene-ethylene random copolymer fraction (R-PP1), and 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).

[0194] Particularly preferably, 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).

[0195] 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).

[0196] 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 remaining parts should not exceed 5.0 wt.%, preferably not more than 3.0 wt.%, for example not more than 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 contain a small amount of additives (A) selected from antioxidants, stabilizers, fillers, colorants, nucleating agents and antistatic agents. In general, they can be incorporated during the compounding process of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0197] If the single-phase propylene-ethylene random copolymer composition (R-PP) comprises an α-nucleating agent, it is preferably free of β-nucleating agents. The α-nucleating agent is preferably selected from the following:

[0198] (i) salts of mono- and polycarboxylic acids, for example sodium benzoate or aluminium tert-butylbenzoate, and

[0199] (ii) dibenzylidene sorbitol (e.g. 1,3:2,4 dibenzylidene sorbitol) and C1-C8 alkyl-substituted dibenzylidene sorbitol derivatives, such as methyl dibenzylidene sorbitol, ethyl dibenzylidene sorbitol or dimethyl dibenzylidene 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

[0200] (iii) salts of phosphoric acid diesters, for example 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

[0201] (iv) vinyl cycloalkane polymers and vinyl alkane polymers (discussed in detail below), and

[0202] (v) mixtures thereof.

[0203] These additives are generally commercially available and are described, for example, in “Plastic Additives Handbook” by Hans Zweifel, pp. 871 to 873, 5th edition, 2001.

[0204] It is to be understood that the content 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.

[0205] 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).

[0206] First propylene-ethylene random copolymer part (R-PP1)

[0207] The first propylene-ethylene random copolymer fraction (R-PP1) is a copolymer of propylene and ethylene.

[0208] 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%.

[0209] The melt flow rate (MFR2) of the first propylene-ethylene random copolymer part (R-PP1) measured at 230°C and 2.16 kg load 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.

[0210] 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, 2.16 kg load and expressed in g / 10 min), i.e. [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.

[0211] Additionally or alternatively, the single-phase propylene-ethylene random copolymer composition (R-PP) may be bimodal in terms of 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.

[0212] Second propylene-ethylene random copolymer part (R-PP2)

[0213] The second propylene-ethylene random copolymer fraction (R-PP2) is a copolymer of propylene and ethylene.

[0214] 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%.

[0215] The melt flow rate (MFR2) of the second propylene-ethylene random copolymer part (R-PP2) measured at 230°C and 2.16 kg load 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.

[0216] Second aspect

[0217] In a second aspect, the present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP) obtainable by the process of the first aspect, more preferably obtainable by the process of the first aspect.

[0218] 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) according to the second aspect.

[0219] Products

[0220] 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.-%.

[0221] In a particular embodiment, the article consists of a single-phase propylene-ethylene random copolymer composition (R-PP).

[0222] Particularly preferably, the article is a pipe.

[0223] The pipe pressure test stability (20°C, 16 MPa) of the pipe according to ISO 1167-1 and ISO 1167-2 is preferably at least 60 h, more preferably at least 100 h, most preferably at least 400 h.

[0224] 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 6000 h.

[0225] Example

[0226] A. Measurement Method

[0227] Unless otherwise defined, the following definitions of terms and determination methods apply to the general embodiments of the present invention as above, including the claims, as well as the following examples.

[0228] Quantification of microstructure by NMR spectroscopy

[0229] Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the isotacticity and regioregularity of the polymers.

[0230] 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 The C-optimized 10 mm extended temperature probe was recorded at 125 °C and nitrogen was used for all pneumatics.

[0231] For polymers, approximately 200 mg of material was dissolved in 1,2-tetrachloroethane-d2 (TCE-d2). To ensure homogeneity of the solution, the NMR tube was further heated in a rotary oven for at least 1 hour after initial sample preparation in a heating block. 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 stereoregularity 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.

[0232] A proprietary computer program was used to quantify 13 C{ 1 H} NMR spectra are processed, integrated, and relevant quantitative properties are determined from the integration.

[0233] For propylene homopolymers, all chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

[0234] Characteristic signals corresponding to regional 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.

[0235] The stereoregularity distribution is quantified by integrating the methyl region between 23.6-19.7 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).

[0236] Specifically, the effects of regio defects and comonomers on the quantification of the tacticity distribution are corrected by subtracting representative regio defect and comonomer integrals from the specific integrated region of the stereo sequence.

[0237] Isotacticity is determined at the pentad level and is reported as the percentage of isotactic pentad (mmmm) sequences over all pentad sequences:

[0238] [mmmm]% = 100*(mmmm / sum of all quintuples)

[0239] 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).

[0240] The amount of 2,1-erythro regio defects was quantified using the average integral of two characteristic methyl sites at 17.7 and 17.2 ppm:

[0241] P 21e =(I e6 +I e8 ) / 2

[0242] 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:

[0243] P 12 =I CH3 +P 12e

[0244] The total amount of propene is quantified as the sum of the primary inserted propene and all other regio defects present:

[0245] P 总 =P 12 +P 21e

[0246] The mole percentage of 2,1 erythro regio defects relative to all propylene was quantified:

[0247] [21e]mol%=100*(P 21e / P 总 )

[0248] 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 spectral region of the H} spectrum. This method was chosen because of its robustness and ability to account for the presence of regio defects when required. Slight adjustments to the integration region were made to improve applicability over the entire range of comonomer content encountered.

[0249] 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 non-zero 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 the absolute ethylene content:

[0250] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0251] By using this set of sites, the corresponding integration formula becomes:

[0252] E=0.5(I H +I G +0.5(I C +I D ))

[0253] 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.

[0254] Calculate the mole percentage of comonomer incorporation based on the mole fraction:

[0255] E[mol%]=100*fE

[0256] Calculate the weight percent of comonomer incorporation based on the mole fraction:

[0257] E[weight%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0258] 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 because of its robustness and slight adjustments to the integration region to improve applicability to a wider range of comonomer contents.

[0259] 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)):

[0260]

[0261] In the formula,

[0262] I(E) is the relative content of isolated ethylene sequences and block ethylene sequences [in %];

[0263] fPEP is the mole fraction of propylene / ethylene / propylene sequence (PEP) in the sample;

[0264] fPEE is the mole fraction of propylene / ethylene / ethylene sequences (PEE) and ethylene / ethylene / propylene sequences (EEP) in the sample;

[0265] fEEE is the mole fraction of ethylene / ethylene / ethylene sequences (EEE) in the sample.

[0266] Calculate the comonomer content of the second propylene-ethylene random copolymer fraction (R-PP2):

[0267]

[0268] In the formula,

[0269] w(PP1) is the weight fraction [in wt. %] of the first propylene-ethylene random copolymer fraction (R-PP1),

[0270] w(PP2) is the weight fraction [in wt. %] of the second propylene-ethylene random copolymer fraction (R-PP2),

[0271] 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),

[0272] C(PP2) is the calculated comonomer content [in mol %] of the second propylene-ethylene random copolymer fraction (R-PP2).

[0273] Melt flow rate

[0274] The melt flow rate (MFR) is determined according to ISO 1133 and is expressed in g / 10 min. The MFR is an indicator of the fluidity and therefore the processability of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polypropylene is determined at a temperature of 230°C and a load of 2.16 kg.

[0275] Calculate the melt flow rate MFR2 (230°C) of the second propylene-ethylene random copolymer part (PP2):

[0276]

[0277] In the formula,

[0278] w(PP1) is the weight fraction [in wt. %] of the first propylene-ethylene random copolymer fraction (R-PP1),

[0279] w(PP2) is the weight fraction [in wt. %] of the second propylene-ethylene random copolymer fraction (R-PP2),

[0280] MFR(PP1) is the melt flow rate MFR2 (230°C) [in g / 10 min] of the first propylene-ethylene random copolymer fraction (R-PP1),

[0281] MFR(PP) is the melt flow rate MFR2 (230°C) [in g / 10 min] of the single-phase propylene-ethylene random copolymer composition (R-PP),

[0282] 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].

[0283] 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).

[0284] Number average molecular weight (M n ), weight average molecular weight (M w ), size average molecular weight and molecular weight distribution (MWD)

[0285] 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.

[0286] Chromatography (GPC) was performed according to ISO 16014-4:2003 and ASTM D 6474-99.A.

[0287] A PolymerChar GPC instrument equipped with an infrared (IR) detector was used with 3xOlexis and lx Olexis guard columns from Polymer Laboratories, with 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methyl-phenol) as solvent, at 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. The Mark Houwink constants for PS, PE and PP are 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).

[0288] 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 on 5 to 7 mg samples using a TA Instrument Q200 Differential Scanning Calorimetry (DSC). The DSC was run in a heating / cooling / heating cycle at a scan rate of 10°C / min in the temperature range of -30 to +225°C according to ISO 11357 / Part 3 / Method C2. 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.

[0289] The glass transition temperature Tg was determined by dynamic mechanical analysis according to ISO 6721-7. The samples were subjected to a 30 % tungsten (40 x 10 x 1 mm), with 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.

[0290] The flexural modulus is determined according to ISO 178 method A (3-point bending test) with a 80 mm x 10 mm x 4 mm specimen. According to the standard, a test speed of 2 mm / min and a span length of 16 times the thickness are used. The test temperature is 23 ± 2 ° C. Injection molding is performed according to ISO19069-2, and the melt temperature is 230 ° C for all materials, regardless of the material melt flow rate.

[0291] Notched Impact Strength (NIS)

[0292] 80x10x4 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 bar test specimens at a melt temperature of 230°C for all materials, regardless of the material melt flow rate.

[0293] Pipeline pressure testing

[0294] The pressure test performance of pipes made of the inventive composition and the comparative composition was tested 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 a temperature of 20° C. (or a stress of 4.6 MPa at a temperature of 95° C.) in a water-water apparatus according to ISO 1167-1. The time to failure (in hours) was recorded, and the time with "still in operation" indicated that the time to failure had not yet been reached at the time of filing this patent application.

[0295] B. Examples

[0296] The metallocene complex used in the polymerization method of the inventive example is trans-dimethylsilanediyl[2-methyl-4,8-di(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-s-indane-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.

[0297] For inventive examples IE1 and IE2 and reference example RE1, the preparation method of the catalyst system is similar to the inventive catalyst system 3 (ICS3) in WO 2020 / 239602A1, and for inventive examples IE3 and IE4, the preparation method of the catalyst system is similar to the comparative catalyst system 4 (CCS4) in WO 2020 / 239602 A1.

[0298] 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 the 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.

[0299] 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 external donor.

[0300] Inventive Examples IE1 to IE4, Comparative Examples CE2 and CE3 and Reference Example RE1 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 part (i.e. R-PP2) and are calculated from the values ​​measured after the loop reactor (i.e. R-PP1) and in the final microparticle (i.e. R-PP), using the appropriate mixing rules as given in the determination methods).

[0301] CE1 is a commercially available grade RA130E (available from Borealis AG), which is a unimodal propylene-ethylene random copolymer produced using a Ziegler-Natta catalyst.

[0302] Table 1: Polymerization conditions of propylene-ethylene random copolymers of inventive examples, comparative examples and reference examples

[0303]

[0304]

[0305] Table 2: Properties of propylene-ethylene random copolymers of inventive examples, comparative examples and reference examples

[0306]

[0307] As can be seen in Table 2, the melt flow rates of the (SSC-catalyzed) inventive examples are comparable to those of the (ZN-catalyzed) comparative examples, while comparable ethylene content results in a substantially higher XCS content in the comparative examples (7 to 9 wt % compared to less than 1 wt %). This lower extractables content means that the inventive compositions are more suitable for pipe applications, particularly for transporting drinking water, as far less oligomers (and other extractables) leach into the water.

[0308] Furthermore, it can be seen from Table 1 that the total productivity of the composition of the present invention (i.e. using the catalyst according to claim 1) is much higher than that of the comparative example, which means that less catalyst residue is present in the final composition (also beneficial to avoid leaching into the fluid transported in the pipeline) and has economic benefits (more PP can be produced using less catalyst).

[0309] Pipes with a diameter of 32 mm and a wall thickness of 3 mm were produced according to ISO 1167-2 using the CE1, RE1 and IE4 compositions.

[0310] Table 3: Pipeline pressure test results of propylene-ethylene random copolymers using inventive examples and comparative examples

[0311]

[0312] As can be seen from Table 3, the performance of the composition prepared according to the present invention is much better than that of the comparative example and the reference example. The effect of using different catalysts can be seen by comparing RE1 with CE1, and the effect of bimodal can be seen by comparing IE4 with RE1. The bimodal SSC catalytic composition performs well under both test conditions.

Claims

1. A method for preparing a single-phase propylene-ethylene random copolymer composition (R-PP) having a melt flow rate (MFR2) in the range of 0.01 to 1.00 g / 10 min measured at 230° C. and 2.16 kg load according to ISO 1133, the method 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; c) transferring the first polymerization mixture to a second polymerization reactor, which is preferably a gas phase reactor; d) 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; e) removing the second polymerization mixture from the second polymerization reactor; and f) optionally, compounding a second polymerization mixture, preferably adding additive (A); 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.

2. The method according to claim 1, wherein: The metallocene complex has the structure of formula (Ia): 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 1 Not hydrogen, R' is C1-C 10 A hydrocarbon group, preferably a C1-C4 hydrocarbon group, more preferably a methyl group, and 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.

3. The method according to claim 1 or 2, wherein: The metallocene complex is selected from the following: 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.

4. A method according to any one of the preceding claims, wherein: The single-phase propylene-ethylene random copolymer composition (R-PP) is obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is in the range of 1.5 to 7.5 mol%.

5. A method according to any one of the preceding claims, wherein: 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 5.0 wt%.

6. A method according to any one of the preceding claims, wherein: The single-phase propylene-ethylene random copolymer composition (R-PP) has a melting temperature (Tm) in the range of 120 to 150°C as determined according to DSC analysis.

7. A method according to any one of the preceding claims, wherein: The single-phase propylene-ethylene random copolymer composition (R-PP) has a crystallization temperature (Tc) in the range of 80 to 110°C as determined by DSC analysis.

8. A method 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.-% of a first propylene-ethylene random copolymer fraction (R-PP1), relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP); 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).

9. A method according to any one of the preceding claims, wherein: The first propylene-ethylene random copolymer part (R-PP1) is obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is in the range of 0.6 to 4.50 mol%, and the second propylene-ethylene random copolymer part (R-PP2) is obtained by 13 The ethylene content (C2) determined by C-NMR spectroscopy is in the range of 0.9 to 9.0 mol%.

10. A method according to any one of the preceding claims, wherein: The melt flow rate (MFR2) of the first propylene-ethylene random copolymer part (R-PP1) measured at 230°C and a load of 2.16 kg according to ISO1133 is in the range of 0.01 to 4.0 g / 10 min, and the melt flow rate (MFR2) of the second propylene-ethylene random copolymer part (R-PP2) measured at 230°C and a load of 2.16 kg according to ISO1133 is in the range of 0.01 to 1.00 g / 10 min.

11. A method according to any one of the preceding claims, 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 part (R-PP1), i.e. [C2(R-PP)] / [C2(R-PP1)], is in the range of 1.00 to 3.00, and the ethylene content is quantitatively determined. 13 The content was determined by C-NMR spectroscopy and expressed in mol%.

12. A method according to any one of the preceding claims, 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 ISO1133 at 230°C and 2.16 kg load and is expressed in g / 10min.

13. A monophasic propylene-ethylene random copolymer composition (R-PP) obtainable, more preferably by, a process according to any one of the preceding claims.

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

15. The article of claim 14, wherein: The article is a pipe having the following characteristics: Pipe pressure test stability for at least 60 h (20 °C, 16 MPa) according to ISO 1167-1 and ISO 1167-2, and / or Pipeline pressure test stability for at least 200h (95°C, 4.6MPa) according to ISO 1167-1 and ISO 1167-2.

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