propylene-ethylene random copolymer having a high degree of random ethylene distribution

Abstract

A single-phase propylene-ethylene random copolymer composition (R-PP) having a melting temperature in the range of 120 to 145 °C, a 2,1 regiodefects content in the range of 0.05 to 1.40 mol%, a relative content of isolated ethylene sequences to block ethylene sequences I(E) greater than or equal to 70.0%, and satisfying the inequality (I): I(E) - 3.79[C2(R-PP)] > 52.0 (I), the single-phase propylene-ethylene random copolymer composition (R-PP) comprising: a) 30 to 70 wt% of a first propylene-ethylene random copolymer fraction (R-PP1) having an ethylene content in the range of 0.1 to 5.0 mol%; b) 30 to 70 wt% of a second propylene-ethylene random copolymer fraction (R-PP2) having an ethylene content in the range of 0.1 to 10.0 mol%; wherein [C2(R-PP)] / [C2(R-PP1)] is greater than or equal to 1.00.

Description

Technical Field

[0001] This invention relates to a single-phase propylene-ethylene random copolymer composition, articles comprising the composition, particularly films, and a method for producing the composition. Background Technology

[0002] Propylene-ethylene copolymers are widely used in film manufacturing due to their advantageous balance of optical, mechanical, and sealing properties. High transparency and high impact strength are particularly valued. While solutions exist in the art that achieve excellent results in optimizing one or more of these properties, improvement in one property often comes at the expense of another.

[0003] WO 2014 / 154610 A1 describes bimodal random propylene-ethylene copolymers polymerized in the presence of a metallocene catalyst, exhibiting high xylene cold-soluble content. These copolymers are well-suited for packaging applications, but the optical, mechanical, or sealing properties of the films are not discussed. Furthermore, the high soluble fraction content limits their suitability for certain food contact and medical applications.

[0004] WO 2014 / 187686 A1 describes a bimodal random propylene-ethylene copolymer polymerized in the presence of a Ziegler-Natta catalyst, exhibiting a moderate level of isolated ethylene sequences and block ethylene sequences (i.e., randomness). While impressive mechanical properties were observed, there is room for further improvement in optical properties, and sealing performance is not discussed. Furthermore, the high ethylene content here also leads to a high soluble fraction content, thus limiting applicability.

[0005] The object of the present invention is to provide a polymer composition that enables those skilled in the art to produce a film, more preferably a blown film, having a beneficial balance of optical, mechanical and sealing properties, while also being characterized by a low soluble fraction content. Summary of the Invention

[0006] This invention is based on the discovery that a single-phase propylene-ethylene random copolymer composition containing two propylene-ethylene random copolymer fractions, having a defined ethylene content and a particularly high relative content of isolated ethylene sequences to block ethylene sequences, has improved optical, mechanical, and sealing properties.

[0007] This invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP), comprising:

[0008] a) a first propylene-ethylene random copolymer fraction (R-PP1) comprising 30 to 70% by weight relative to the total weight of the propylene-ethylene random copolymer composition (R-PP), wherein the first propylene-ethylene random copolymer fraction (R-PP1) has a content in the range of 0.1 to 5.0 mol% by quantitative analysis. 13 Ethylene content determined by C-NMR spectroscopy;

[0009] b) A second propylene-ethylene random copolymer fraction (R-PP2) comprising 30 to 70% by weight relative to the total weight of the propylene-ethylene random copolymer composition (R-PP), wherein the second propylene-ethylene random copolymer fraction (R-PP2) has a content in the range of 0.1 to 10.0 mol% by quantitative analysis. 13 Ethylene content determined by C-NMR spectroscopy;

[0010] The combination of the first propylene-ethylene random copolymer fraction (R-PP1) and the second propylene-ethylene random copolymer fraction (R-PP2) constitutes at least 90% by weight of the total weight of the propylene-ethylene random copolymer composition (R-PP).

[0011] The propylene-ethylene random copolymer composition (R-PP) was quantitatively analyzed. 13 The ethylene content, determined by C-NMR spectroscopy and expressed as mol%, was compared with the first propylene-ethylene random copolymer fraction (R-PP1) by quantitative analysis. 13 The ratio of ethylene content ([C2(R-PP)] / [C2(R-PP1)]) determined by C-NMR spectroscopy and expressed in mol% is greater than or equal to 1.00.

[0012] The propylene-ethylene random copolymer composition (R-PP) has a melting temperature in the range of 120 to 145°C as determined by DSC analysis and a molecular weight percentage in the range of 0.05 to 1.40 mol%. 13 The content of defects in the 2,1-region was determined by C-NMR spectroscopy.

[0013] The propylene-ethylene random copolymer composition (R-PP) has a relative content I(E) of more than or equal to 70.0% of isolated ethylene sequences and block ethylene sequences, and the relative content I(E) of isolated ethylene sequences and block ethylene sequences and the C2 content C2(R-PP) of the propylene-ethylene random copolymer composition satisfy inequality (I).

[0014] I(E)-3.79[C2(R-PP)]≥52.0(I),

[0015] The content of I(E) is defined by equation (II):

[0016]

[0017] in

[0018] I(E) is the relative content of isolated ethylene sequences and block ethylene sequences [in %];

[0019] fPEP is the mole fraction of propylene / ethylene / propylene sequence (PEP) in the sample;

[0020] fPEE is the mole fraction of the propylene / ethylene / ethylene sequence (PEE) and the ethylene / ethylene / propylene sequence (EEP) in the sample;

[0021] fEEE is the mole fraction of ethylene / ethylene / ethylene sequence (EEE) in the sample.

[0022] All sequence concentrations are based on 13 Statistical triadic analysis of C-NMR data.

[0023] In another embodiment, the present invention relates to a method for producing the single-phase propylene-ethylene random copolymer composition (R-PP) of the present invention, comprising the following steps:

[0024] a) Polymerizing propylene and ethylene comonomer units in the presence of a single active 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 active site catalyst, wherein the first polymerization reactor is preferably a slurry reactor, more preferably a loop reactor;

[0025] b) Transferring the first polymerization mixture to a second polymerization reactor, preferably a gas-phase reactor;

[0026] c) Polymerizing propylene and ethylene comonomer units in the second polymerization reactor in the presence of the single-active-site catalyst 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-active-site catalyst;

[0027] d) Extract the second polymerization mixture from the second polymerization reactor; and

[0028] e) The second polymerization mixture is compounded, optionally with the addition of additives, to form a single-phase propylene-ethylene random copolymer composition (R-PP).

[0029] In a final embodiment, the present invention relates to an article, more preferably a film, comprising at least 75% by weight, more preferably at least 90% by weight, and most preferably at least 95% by weight of the single-phase propylene-ethylene random copolymer composition (R-PP) of the present invention.

[0030] definition

[0031] 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 this invention pertains. Although any methods and materials similar to or equivalent to those described herein may be used in practice to test the invention, preferred materials and methods are described herein. In describing and claiming protection for this invention, the following terms will be used in accordance with the definitions stated below.

[0032] Unless otherwise expressly stated, the terms “a”, “an”, etc., are used to refer to one or more.

[0033] In the following text, unless otherwise stated, quantities are given in weight % (wt%).

[0034] Propylene homopolymers are polymers that are essentially composed of propylene monomer units. Due to impurities, especially in industrial polymerization processes, propylene homopolymers may contain up to 0.1 mol% of comonomer units, preferably up to 0.05 mol% of comonomer units, and most preferably up to 0.01 mol% of comonomer units.

[0035] 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 from one or more comonomers having different numbers of carbon atoms.

[0036] For single-phase propylene homopolymers and single-phase propylene random copolymers, there is typically only one glass transition temperature.

[0037] Bimodal polymers are polymers with a bimodal distribution exhibiting one or more properties. Bimodal random propylene-ethylene copolymers can typically be bimodal in terms of ethylene content or in terms of molecular weight (as can be seen by the melt flow rates of the first fraction and the final composition). Detailed Implementation

[0038] The single-phase propylene-ethylene random copolymer composition (R-PP) comprises 30 to 70% by weight 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 30 to 70% by weight 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).

[0039] More preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) comprises 45 to 67% by weight 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 33 to 55% by weight 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).

[0040] Particularly preferred is that the single-phase propylene-ethylene random copolymer composition (R-PP) comprises 55 to 64% by weight 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 36 to 45% by weight 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).

[0041] The combination of the first propylene-ethylene random copolymer fraction (R-PP1) and the second propylene-ethylene random copolymer fraction (R-PP2) constitutes a single-phase propylene-ethylene random copolymer composition (R-PP) of at least 90% by weight, more preferably at least 95% by weight, and most preferably at least 97% by weight.

[0042] 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, the remaining portion shall not exceed 5.0% by weight, preferably not more than 3.0% by weight, and such as not more than 2.0% by weight, 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 additive (A), selected from the group consisting of antioxidants, stabilizers, fillers, colorants, nucleating agents, and antistatic agents. Typically, these may be incorporated during the compounding of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0043] When a single-phase propylene-ethylene random copolymer composition (R-PP) contains an α-nucleating agent, it is preferable that it does not contain a β-nucleating agent. Preferably, the α-nucleating agent is selected from the group consisting of the following:

[0044] (i) Salts of monocarboxylic and polycarboxylic acids, such as sodium benzoate or aluminum tert-butylbenzoate, and

[0045] (ii) Dibenzyl sorbitol (e.g., 1,3:2,4-dibenzyl sorbitol) and C1-C8-alkyl-substituted dibenzyl sorbitol derivatives, such as methyl dibenzyl sorbitol, ethyl dibenzyl sorbitol, or dimethyl dibenzyl sorbitol (e.g., 1,3:2,4-di(methylbenzyl)sorbitol), or substituted nonitol derivatives, such as 1,2,3,-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol, and

[0046] (iii) Salts of diesters of phosphate, such as sodium 2,2'-methylenebis(4,6'-di-tert-butylphenyl)phosphate or aluminum bis[2,2'-methylene-bis(4,6'-di-tert-butylphenyl)phosphate]hydroxy, and

[0047] (iv) Vinylcycloalkane polymers and vinylalkane polymers (discussed in more detail below), and

[0048] (v) Their mixture.

[0049] Such additives are generally commercially available and are described, for example, in Hans Zweifel’s “Plastic Additives Handbook”, pp. 871-873, 5th edition, 2001.

[0050] It should be understood that the amount of additive (A) given relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP) includes any carrier polymer used to introduce the additive into the single-phase propylene-ethylene random copolymer composition (R-PP), i.e., a masterbatch carrier polymer. An example of such a carrier polymer is a polypropylene homopolymer in powder form.

[0051] In one particular embodiment, the single-phase propylene-ethylene random copolymer composition (R-PP) comprises a first propylene-ethylene random copolymer fraction (R-PP1), a second propylene-ethylene random copolymer fraction (R-PP2), and an optional additive (A).

[0052] First propylene-ethylene random copolymer fraction (R-PP1)

[0053] The first propylene-ethylene random copolymer fraction (R-PP1) is a copolymer of propylene and ethylene.

[0054] The first propylene-ethylene random copolymer fraction (R-PP1) has a content in the range of 0.1 to 5.0 mol%, more preferably in the range of 1.0 to 4.0 mol%, and most preferably in the range of 1.5 to 3.5 mol%. 13 Ethylene content (C2) determined by C-NMR spectroscopy.

[0055] Preferably, the first propylene-ethylene random copolymer fraction (R-PP1) 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 0.3 to 20 g / 10 min, more preferably in the range of 0.5 to 15 g / 10 min, and most preferably in the range of 1.5 to 11 g / 10 min.

[0056] Second propylene-ethylene random copolymer fraction (R-PP2)

[0057] The second propylene-ethylene random copolymer fraction (R-PP2) is a copolymer of propylene and ethylene.

[0058] The second propylene-ethylene random copolymer fraction (R-PP2) has a content in the range of 0.1 to 10.0 mol%, more preferably in the range of 2.0 to 8.0 mol%, and most preferably in the range of 3.0 to 7.0 mol%. 13 Ethylene content (C2) determined by C-NMR spectroscopy.

[0059] Preferably, the second propylene-ethylene random copolymer fraction (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 0.3 to 20 g / 10 min, more preferably in the range of 0.5 to 15 g / 10 min, and most preferably in the range of 1.5 to 11 g / 10 min.

[0060] Properties of single-phase propylene-ethylene random copolymer compositions (R-PP)

[0061] The single-phase propylene-ethylene random copolymer composition (R-PP) 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 0.3 to 20 g / 10 min, more preferably in the range of 0.5 to 15 g / 10 min, and most preferably in the range of 1.5 to 11 g / 10 min.

[0062] The single-phase propylene-ethylene random copolymer composition (R-PP) can be bimodal in terms of molecular weight (as shown by the melt flow rate value). Therefore, it is preferred that the ratio of the melt flow rate (MFR2) of the single-phase propylene-ethylene random copolymer composition (R-PP) measured according to ISO 1133 at 230°C and under a load of 2.16 kg and expressed in g / 10 min to the melt flow rate (MFR2) of the first propylene-ethylene random copolymer fraction (R-PP1) measured according to ISO 1133 at 230°C and under a load of 2.16 kg and expressed in g / 10 min ([MFR(R-PP)] / [MFR(R-PP1)]) is less than 1.00.

[0063] The single-phase propylene-ethylene random copolymer composition (R-PP) has a permeability in the range of 0.1 to 10.0 mol%, more preferably in the range of 1.0 to 7.0 mol%, and most preferably in the range of 2.0 to 5.0 mol%. 13 Ethylene content (C2) determined by C-NMR spectroscopy.

[0064] The single-phase propylene-ethylene random copolymer composition (R-PP) can be bimodal in terms of ethylene content. Therefore, the single-phase propylene-ethylene random copolymer composition (R-PP) can be quantitatively analyzed. 13 The ethylene content, determined by C-NMR spectroscopy and expressed as mol%, was compared with the first propylene-ethylene random copolymer fraction (R-PP1) by quantitative analysis. 13 The ratio of ethylene content ([C2(R-PP)] / [C2(R-PP1)]) as determined by C-NMR spectroscopy and expressed in mol% is greater than or equal to 1.00, more preferably in the range of 1.10 to 3.00, and most preferably in the range of 1.25 to 2.00.

[0065] The term "2,1 region defect" used in this invention is defined as the sum of 2,1 Eurasian region defects and 2,1 Soviet region defects.

[0066] The presence of defects in the 2,1-region of the single-phase propylene-ethylene random copolymer composition (R-PP) indicates that the random propylene copolymer (R-PP) has been polymerized in the presence of a single active center catalyst (SSC).

[0067] Therefore, it is also preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) is polymerized in the presence of a single active center catalyst (SSC), more preferably a metallocene catalyst.

[0068] The single-phase propylene-ethylene random copolymer composition (R-PP) also has a content in the range of 0.05 to 1.40 mol%, more preferably in the range of 0.40 to 1.00 mol%, and most preferably in the range of 0.65 to 0.85 mol%, as determined by quantitative analysis. 13 The content of defects in the 2,1- region was determined by C-NMR spectroscopy.

[0069] The content of 2,1-region defects may depend on the amount of comonomer, with higher amounts of comonomer generally associated with lower 2,1-region defect content.

[0070] The content of 2,1-region defects may also depend on the polymerization temperature, with higher temperatures generally associated with lower 2,1-region defect content.

[0071] Preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a xylene cold soluble content (XCS) as determined according to ISO 16152, in the range of 0.05 to 15.0% by weight, more preferably in the range of 0.10 to 8.0% by weight, most preferably in the range of 0.15 to 4.0% by weight, such as in the range of 0.20 to 3.0% by weight.

[0072] Since the single-phase propylene-ethylene random copolymer composition (R-PP) is not a multiphase system containing an elastomer rubber layer, the single-phase propylene-ethylene random copolymer composition (R-PP) preferably does not have a glass transition temperature below -30°C, more preferably does not have a glass transition temperature below -25°C, and most preferably does not have a glass transition temperature below -20°C.

[0073] The single-phase propylene-ethylene random copolymer composition (R-PP) has a melting temperature determined according to DSC analysis in the range of 120 to 145°C, more preferably in the range of 124 to 140°C, and most preferably in the range of 128 to 135°C.

[0074] It is also preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) has a crystallization temperature determined according to DSC analysis in the range of 88 to 100°C, more preferably in the range of 89 to 99°C, and most preferably in the range of 90 to 98°C.

[0075] The single-phase propylene-ethylene random copolymer composition (R-PP) is further defined by the relative content I(E) of its isolated ethylene sequence and block ethylene sequence.

[0076] The content of I(E) is defined by equation (II):

[0077]

[0078] in

[0079] I(E) is the relative content of isolated ethylene sequences and block ethylene sequences [in %];

[0080] fPEP is the mole fraction of propylene / ethylene / propylene sequence (PEP) in the sample;

[0081] fPEE is the mole fraction of the propylene / ethylene / ethylene sequence (PEE) and the ethylene / ethylene / propylene sequence (EEP) in the sample;

[0082] fEEE is the mole fraction of ethylene / ethylene / ethylene sequence (EEE) in the sample.

[0083] All sequence concentrations are based on 13 Statistical triadic analysis of C-NMR data.

[0084] This parameter serves as an indicator of the degree of randomness in the insertion of ethylene into the polypropylene chain.

[0085] The single-phase propylene-ethylene random copolymer composition (R-PP) has a relative content (I(E) of 70.0%, more preferably 71.0%, and most preferably 73.0% of isolated ethylene sequences to block ethylene sequences. The value of I(E) is generally not higher than 95.0%.

[0086] Furthermore, it is known that the relative content I(E) of isolated ethylene sequences and block ethylene sequences depends on the total ethylene content; the higher the total ethylene content, the higher the I(E) value.

[0087] Therefore, the single-phase propylene-ethylene random copolymer composition (R-PP) is further characterized by the relationship between the I(E) value and the total ethylene content.

[0088] The relative content I(E) of isolated ethylene sequences and block ethylene sequences and the C2 content C2(R-PP) of the propylene-ethylene random copolymer composition must satisfy inequality (I):

[0089] I(E)-3.79[C2(R-PP)]≥52.0(I),

[0090] More preferably, the relative content I(E) of isolated ethylene sequences to block ethylene sequences and the C2 content C2(R-PP) of the propylene-ethylene random copolymer composition satisfy inequality (Ia):

[0091] I(E)-3.79[C2(R-PP)]≥57.0(Ia).

[0092] Most preferably, the relative content I(E) of isolated ethylene sequences to block ethylene sequences and the C2 content C2(R-PP) of the propylene-ethylene random copolymer composition satisfy inequality (Ib).

[0093] I(E)-3.79[C2(R-PP)]≥61.0(Ib).

[0094] Preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has an 80×10×4mm diameter, injection molded according to EN ISO 1873-2, within the range of 500 to 1500 MPa, more preferably within the range of 600 to 1200 MPa, and most preferably within the range of 700 to 1000 MPa, in the range of ISO 178. 3 The flexural modulus is determined by the test bar.

[0095] Furthermore, the single-phase propylene-ethylene random copolymer composition (R-PP) exhibits a strength ranging from 2.0 to 20.0 kJ / m³. 2 More preferably, it is within the range of 3.5 to 15.0 kJ / m 2 Within this range, the most preferred value is between 5.0 and 10.0 kJ / m³. 2 Within the scope of ISO 179, use injection molding of 80×10×4mm according to EN ISO 1873-2. 3 The notched impact strength of a simply supported beam at 23°C was measured on a test bar.

[0096] Preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has at least one of a variety of properties commonly used to characterize films, as measured on a 50 μm blown film produced from the single-phase propylene-ethylene random copolymer composition (R-PP).

[0097] Therefore, it is preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) has a seal initiation temperature (SIT) measured on a 50 μm blown film in the range of 105 to 130°C, more preferably in the range of 109 to 125°C, and most preferably in the range of 113 to 120°C.

[0098] The difference between the melting temperature and the sealing initiation temperature (SIT) of the single-phase propylene-ethylene random copolymer composition (R-PP), as determined by DSC analysis, is preferably in the range of 10 to 25°C, more preferably in the range of 12 to 20°C, and most preferably in the range of 14 to 17°C.

[0099] Preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a dart impact strength (DDI) measured on a 50 μm blown film according to ASTM D1709 Method A in the range of 40 to 100 g, more preferably in the range of 45 to 90 g, and most preferably in the range of 50 to 80 g.

[0100] It is also preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) has a tensile modulus in the longitudinal direction (MD) measured on a 50 μm blown film according to ISO 527-3 in the range of 500 to 2000 MPa, more preferably in the range of 700 to 1600 MPa, and most preferably in the range of 800 to 1200 MPa.

[0101] Further preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a tensile modulus in the transverse (TD) direction, measured according to ISO 527-3 on a 50 μm blown film, in the range of 500 to 2000 MPa, more preferably in the range of 800 to 1700 MPa, and most preferably in the range of 1000 to 1400 MPa.

[0102] Finally, preferably, the single-phase propylene-ethylene random copolymer composition (R-PP) has a haze value measured on a 50 μm blown film according to ASTM D1003 in the range of 0.0 to 10.0%, more preferably in the range of 0.0 to 8.0%, and most preferably in the range of 0.0 to 6.0%.

[0103] method

[0104] The present invention further relates to a method for producing a single-phase propylene-ethylene random copolymer composition (R-PP) according to the present invention.

[0105] The method includes the following steps:

[0106] a) Polymerizing propylene and ethylene comonomer units in the presence of a single active site catalyst in a first polymerization reactor (R1) to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and a single active site catalyst, wherein the first polymerization reactor is preferably a slurry reactor (SR), more preferably a loop reactor (LR).

[0107] b) Transfer the first polymerization mixture to a second polymerization reactor (R2), preferably a gas-phase reactor (GPR);

[0108] c) In the second polymerization reactor (R2), in the presence of the single active site catalyst, polymerize propylene and ethylene comonomer units 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 a single active site catalyst.

[0109] d) Extract the second polymerization mixture from the second polymerization reactor (R2); and

[0110] e) The second polymerization mixture is compounded, optionally with the addition of additives, to form a single-phase propylene-ethylene random copolymer composition (R-PP).

[0111] Preferably, the operating temperature in the first polymerization reactor (R1) is in the range of 62 to 85°C, more preferably in the range of 65 to 82°C, and even more preferably in the range of 67 to 80°C.

[0112] As an alternative to or supplement to the preceding paragraph, it is preferred that the operating temperature in the second polymerization reactor (R2) be in the range of 75 to 95°C, more preferably in the range of 78 to 92°C.

[0113] Typically, the pressure in the first polymerization reactor (R1), preferably the loop reactor (LR), is in the range of 20 to 80 bar, preferably in the range of 30 to 70 bar, such as 35 to 65 bar, while the pressure in the second polymerization reactor (R2), i.e. the gas phase reactor (GPR), is in the range of 5 to 50 bar, preferably in the range of 15 to 40 bar.

[0114] Preferably, hydrogen is added to each polymerization reactor to control the molecular weight, i.e., the melt flow rate MFR2.

[0115] In addition to the (primary) polymerization of the propylene-ethylene random copolymer in two polymerization reactors (R1 and R2), the preparation of the propylene-ethylene random copolymer may also include prepolymerization in a prepolymerization reactor (PR) upstream of the first polymerization reactor (R1).

[0116] Polypropylene (pre-PP) is produced in a prepolymerization reactor (PR). Prepolymerization is carried out in the presence of a single active site catalyst (SSC). According to this embodiment, the single active site catalyst is introduced into the prepolymerization step. However, this does not preclude the option of adding an additional co-catalyst at a later stage, such as in the polymerization process, for example in the first reactor (R1). In one embodiment, if prepolymerization is applied, all components of the single active site catalyst are added only to the prepolymerization reactor (PR).

[0117] The prepolymerization reaction is typically carried out at a temperature of 0 to 60°C, preferably 15 to 50°C, and more preferably 20 to 45°C.

[0118] The pressure in the prepolymerization reactor is not critical, but it must be high enough to keep the reaction mixture in the liquid phase. Therefore, the pressure can be 20 to 100 bar, for example, 30 to 70 bar.

[0119] In a preferred embodiment, prepolymerization is carried out by bulk slurry polymerization in liquid propylene, i.e., the liquid phase mainly comprises propylene, wherein an inert component is optionally dissolved. Furthermore, according to the invention, as described above, ethylene is used as feedstock during prepolymerization.

[0120] Other components may also be added during the prepolymerization stage. Therefore, as is known in the art, hydrogen can be added to the prepolymerization stage to control the molecular weight of polypropylene (pre-PP). Furthermore, antistatic additives can be used to prevent particles from adhering to each other or to the reactor wall.

[0121] Precise control of prepolymerization conditions and reaction parameters is within the scope of the art.

[0122] Due to the aforementioned defined process conditions in prepolymerization, a mixture (MI) of single active site catalyst (SSC) and polypropylene (pre-PP) produced in the prepolymerization reactor (PR) is preferably obtained. Preferably, the single active site catalyst (SSC) is (finely) dispersed in the polypropylene (pre-PP). In other words, the single active site catalyst (SSC) particles introduced into the prepolymerization reactor (PR) are broken into smaller fragments, which are uniformly distributed in the grown polypropylene (pre-PP). The size of the introduced single active site catalyst (SSC) particles and the resulting fragments are not important to this invention and are within the scope of technical knowledge.

[0123] As described above, if prepolymerization is used, the mixture (MI) of the single active site catalyst (SSC) and polypropylene (pre-PP) produced in the prepolymerization reactor (PR) is transferred to the first reactor (R1) after the 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% by weight, more preferably not exceeding 4.0% by weight, and even more preferably in the range of 0.5% to 4.0% by weight, such as in the range of 1.0% to 3.0% by weight.

[0124] Without using prepolymerization, propylene and other components (such as single active center catalyst (SSC)) are directly introduced into the first polymerization reactor (R1).

[0125] In one embodiment, the present invention relates to a single-phase propylene-ethylene random copolymer composition (R-PP) as described above, which can be obtained by the methods described herein, more preferably by the methods described herein. All preferred embodiments and alternative positions given above and below for the single-phase propylene-ethylene random copolymer composition (R-PP) are adapted, as necessary, to single-phase propylene-ethylene random copolymer compositions (R-PP) obtainable by the methods described herein, more preferably by the methods described herein.

[0126] catalyst system

[0127] The single-active-site catalyst according to the present invention can be any supported metallocene catalyst suitable for producing isotactic polypropylene.

[0128] Preferably, the single active site catalyst (SSC) comprises a metallocene complex, a cocatalyst system comprising an aluminoxane cocatalyst, and a silica support.

[0129] In particular, preferably, the single active site catalyst (SSC) contains

[0130] (i) Metallocene complexes having general formula (III)

[0131]

[0132] Each X is independently a σ-donor ligand.

[0133] L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, and -R'2Ge-, wherein each R' is independently a hydrogen atom or optionally contains one or more heteroatoms or fluorine atoms from groups 14 to 16 of the periodic table. 20 - A hydrocarbon group, or optionally two R' groups together, can form a ring.

[0134] Each R 1 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 - hydrocarbon group, and optionally two adjacent R 1 The groups can be part of a ring containing the phenyl carbon to which they are bonded.

[0135] Each R 2 Independently identical or capable of being different, and being CH2-R 8Group, wherein R 8 C is H or a straight chain or a branched chain 1-6 -alkyl, C 3-8 -cycloalkyl, C 6-10 -Aryl,

[0136] R 3 It is a straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -Alkaryl or C6-C 20 -Aryl,

[0137] R 4 For C(R) 9 )3 groups, of which R 9 It is a straight-chain or branched C1-C6-alkyl group.

[0138] R 5 It is aliphatic C1-C atoms, which are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -Hydrocarbon group;

[0139] R 6 It is aliphatic C1-C atoms, which are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -hydrocarbon group; or

[0140] R 5 and R 6 They can form a 5-membered saturated carbon ring, which can be optionally divided by n R... 10 Group substitution, where n is 0 to 4;

[0141] Each R 10 Same or different, and can be C1-C 20 - A hydrocarbon group, or optionally a C1-C group containing one or more heteroatoms belonging to groups 14 to 16 of the periodic table. 20 -Hydrocarbon group;

[0142] R 7 It is H or a straight-chain or branched C1-C6-alkyl group or optionally surrounded by 1 to 3 R groups. 11 Group-substituted aryl or heteroaryl groups having 6 to 20 carbon atoms

[0143] Each R 11 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 -Hydrocarbon group,

[0144] (ii) Aluminoxane co-catalyst, and

[0145] (iii) Silica carrier.

[0146] The term "σ-donor ligand" is well understood by those skilled in the art as a group that bonds to a metal via a σ bond. Therefore, the anionic ligand "X" can be independently 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, and is a straight-chain or branched, cyclic or acyclic C1 to C2 group. 20 Alkyl, C2 to C 20 alkenyl, C2 to C 20 alkynyl group, C3 to C 12 cycloalkyl, C6 to C 20 Aryl, C7 to C 20 Aryl alkyl, C7 to C 20 Alkyl, C8 to C 20 Arylene group, wherein the R' group may optionally contain one or more heteroatoms belonging to groups 14 to 16. In a preferred embodiment, the anionic ligand "X" is the same and is a halogen, such as Cl, or methyl or benzyl.

[0147] Preferred monovalent anionic ligands are halogens, especially chlorine (Cl).

[0148] Preferred complexes for metallocene catalysts include:

[0149] Racemic-dimethylsilylbis[2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride

[0150] Racemic-trans-dimethylsilyl[2-methyl-4-(4′-tert-butylphenyl)-inden-1-yl][2-methyl-4-(4′-tert-butylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0151] Racemic-trans-dimethylsilyl[2-methyl-4-(4′-tert-butylphenyl)-inden-1-yl][2-methyl-4-phenyl-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride,

[0152] Racemic-trans-dimethylsilyl[2-methyl-4-(3',5'-tert-butylphenyl)-1,5,6,7-tetrahydro-symmetric indarsen-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride,

[0153] Racemic-trans-dimethylsilyl[2-methyl-4,8-bis-(4′-tert-butylphenyl)-1,5,6,7-tetrahydro-symmetric indarsen-1-yl][2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride,

[0154] Racemic-trans-dimethylsilyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric-indarsen-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride,

[0155] Racemic-trans-dimethylsilyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric-indarsen-1-yl][2-methyl-4-(3',5'-5-di-tert-butyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride.

[0156] Particularly preferred is racemic-trans-dimethylsilyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric indane-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride.

[0157] The ligands required to form the complexes of the present invention and thus the catalysts of the present invention can be synthesized by any method, and skilled organic chemists are capable of designing various synthetic schemes to produce the necessary ligand materials. For example, WO2007 / 116034 discloses the necessary chemistry. Synthetic schemes can also generally be found in WO 2002 / 02576, WO 2011 / 135004, WO 2012 / 084961, WO 2012 / 001052, WO 2011 / 076780, WO 2015 / 158790 and WO 2018 / 122134. Particular reference is made to WO 2019 / 179959, which describes the most preferred catalyst of the present invention.

[0158] co-catalyst

[0159] In order to form an active catalytic substance, a co-catalyst known in the art is usually required.

[0160] According to the present invention, the aluminoxane cocatalyst is used in combination with the metallocene catalyst complex defined above.

[0161] Aluminoxane cocatalysts can be aluminoxane cocatalysts of formula (IV):

[0162]

[0163] Where n is typically between 6 and 20 and R has the following meanings.

[0164] Aluminoxanes are formed during the partial hydrolysis of organoaluminum compounds, such as compounds having the formulas AlR3, AlR2Y, and Al2R3Y3, where R can be, for example, C1-C2. 10 Alkyl groups, preferably C1-C5 alkyl groups, or C3-C5 alkyl groups. 10 cycloalkyl, C7-C 12 Aryl 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 resulting oxyaluminoxane is usually not a pure compound, but a mixture of oligomers of formula (IV).

[0165] The preferred aluminoxane is methylaluminoxane (MAO). Since the aluminoxanes used as cocatalysts according to the present invention are prepared by means of their own process rather than as pure compounds, the molar concentrations of the aluminoxane solutions mentioned below are based on their aluminum content.

[0166] The catalyst system of the present invention is used in a supported form. The particulate support material used is silica or a mixed oxide, such as silica-alumina, particularly silica. Silica support is preferred. Skilled practitioners know the procedures required for supporting metallocene catalysts.

[0167] In a preferred embodiment, the catalyst system corresponds to CCS4 of WO 2020 / 239602 A1.

[0168] Products

[0169] In the final embodiment, the present invention relates to articles comprising at least 75% by weight, more preferably at least 90% by weight, and most preferably at least 95% by weight of a single-phase propylene-ethylene random copolymer composition (R-PP).

[0170] In addition to the single-phase propylene-ethylene random copolymer composition (R-PP), other polymer components may be present in the article; however, it is preferred that the single-phase propylene-ethylene random copolymer composition (R-PP) is the only polymer component in the article.

[0171] In a particularly preferred embodiment, the article comprises a single-phase propylene-ethylene random copolymer composition (R-PP).

[0172] The article according to the present invention is preferably a film, and more preferably a blown film.

[0173] Preferably, the film, more preferably the blown film, has a thickness in the range of 5 to 100 μm, more preferably in the range of 10 to 80 μm, and most preferably in the range of 20 to 70 μm.

[0174] The film according to the invention, more preferably the blown film, preferably has a sealing initiation temperature (SIT) in the range of 105 to 130°C, more preferably in the range of 109 to 125°C, and most preferably in the range of 113 to 120°C.

[0175] The difference between the melt temperature of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by DSC analysis and the sealing initiation temperature (SIT) of the film, more preferably the blown film, is preferably in the range of 10 to 25°C, more preferably in the range of 12 to 20°C, and most preferably in the range of 14 to 17°C.

[0176] The film according to the invention, more preferably the blown film, preferably has a dart impact strength (DDI) measured according to ASTM D1709 Method A in the range of 40 to 100 g, more preferably in the range of 45 to 90 g, and most preferably in the range of 50 to 80 g.

[0177] The film according to the invention, more preferably the blown film, preferably has a tensile modulus in the longitudinal direction (MD) measured according to ISO 527-3 in the range of 500 to 2000 MPa, more preferably in the range of 700 to 1600 MPa, and most preferably in the range of 800 to 1200 MPa.

[0178] The film according to the invention, more preferably the blown film, preferably has a tensile modulus in the transverse (TD) measured according to ISO 527-3 in the range of 500 to 2000 MPa, more preferably in the range of 800 to 1700 MPa, and most preferably in the range of 1000 to 1400 MPa.

[0179] The film according to the invention, more preferably the blown film, preferably has a haze value measured according to ASTM D1003 in the range of 0.0 to 10.0%, more preferably in the range of 0.0 to 8.0%, and most preferably in the range of 0.0 to 6.0%.

[0180] Example

[0181] A. Measurement Method

[0182] Unless otherwise defined, the following definitions of terms and methods of measurement apply to the above general description of the invention, including the claims, and the following embodiments.

[0183] Quantitative analysis of microstructure using NMR spectroscopy

[0184] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the isotactic regularity and regioregularity of polymers.

[0185] Adopt for 1 H and 13 A Bruker Advance III 400 NMR spectrometer, operating at 400.15 MHz and 100.62 MHz respectively, recorded quantitative data in solution. 13 C{ 1 ¹H NMR spectroscopy. Nitrogen was used for all pneumatic devices, and all spectra were performed using… 13 A C-optimized 10mm extended temperature probe was used to record at 125°C.

[0186] For the polymer, approximately 200 mg of material was dissolved in 1,2-tetrachloroethane-d2 (TCE-d2). To ensure a homogeneous solution, the NMR tube was further heated in a rotary oven for at least 1 hour after initial sample preparation in a heating block. After insertion into the magnet, the tube was rotated at 10 Hz. This setup 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, employing a 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 (8 k) transient values ​​were acquired for each spectrum.

[0187] Using proprietary computer programs for quantitative analysis 13 C{ 1 The H NMR spectra are processed, integrated, and the relevant quantitative properties are determined from the integration.

[0188] For propylene homopolymers, all chemical shifts are internally referenced at 21.85 ppm for the methyl isotactic pentamematic group (mmmm).

[0189] 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.

[0190] The stereoregularity distribution was quantified by integrating the methyl region between 23.6 and 19.7 ppm and correcting for any sites unrelated to 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).

[0191] Specifically, by subtracting representative regional defects and comonomer integrals from specific integral regions of the stereo sequence, the quantitative influence of regional defects and comonomers on the stereoregularity distribution is corrected.

[0192] Isothetic regularity is determined at the quintet level and reported as the percentage of isothetic quintet (mmmm) sequences relative to all quintet sequences:

[0193] [mmmm]% = 100 * (mmmm / sum of all five-unit groups).

[0194] The presence of the 2,1 erythroline region defect was indicated by the presence of two methyl sites at 17.7 and 17.2 ppm, and was confirmed by other characteristic sites. No characteristic signals corresponding to other types of region defects were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0195] The amount of defects in the 2,1 erythrocyanine region was quantified by averaging the integrals of the two characteristic methyl sites at 17.7 and 17.2 ppm.

[0196] P 21e =(I e6 +I e8 ) / 2.

[0197] The amount of primary inserted propene (1,2) is quantified based on the methyl region, with corrections made for sites within this region that are unrelated to the primary insertion and for primary insertion sites not included in this region.

[0198] P 12 =I CH3 +P 12e

[0199] The total amount of propylene was quantified as the sum of primary inserted propylene and all other present regional defects:

[0200] P 总 =P 12 +P 21e

[0201] Quantify the molar percentage of defects in the 2,1 erythroline region relative to all propylene:

[0202] [21e] mole% = 100*(P) 21e / P 总 )

[0203] Using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157), by analyzing the... 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 because of its robustness and ability to indicate the presence of regional defects when needed. Slight adjustments were made to the integration region to improve applicability across the entire range of comonomer contents encountered.

[0204] For systems where only isolated ethylene is observed in the PPEPP sequence, the method of Wang et al. was modified to reduce the influence of non-zero integrals from sites that are known to be absent. This method reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine the absolute ethylene content to the following:

[0205] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0206] By using this set of sites, the corresponding integral equation becomes:

[0207] E = 0.5(I H +I G +0.5(I C +I D ))

[0208] Use the same notation as in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157). No modifications were made to the equations for absolute propylene content.

[0209] Calculate the molar percentage of comonomer incorporated from the molar fraction:

[0210] E[mol%] = 100 * fE

[0211] Calculate the weight percentage of comonomer incorporated using mole fraction:

[0212] E[weight%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0213] The distribution of comonomer sequences at the ternary group level 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 because the integration region was slightly adjusted to increase applicability to a wider range of comonomer contents.

[0214] The relative amounts of isolated ethylene incorporation and block ethylene incorporation were calculated from the ternary sequence distribution using the following relationship (Equation (II)):

[0215]

[0216] in

[0217] I(E) is the relative content of isolated ethylene sequences and block ethylene sequences [in %];

[0218] fPEP is the mole fraction of propylene / ethylene / propylene sequence (PEP) in the sample;

[0219] fPEE is the mole fraction of the propylene / ethylene / ethylene sequence (PEE) and the ethylene / ethylene / propylene sequence (EEP) in the sample;

[0220] fEEE is the mole fraction of the ethylene / ethylene / ethylene sequence (EEE) in the sample.

[0221] Calculate the comonomer content of the second propylene-ethylene random copolymer fraction (R-PP2):

[0222]

[0223] in

[0224] w(PP1) is the weight fraction [in weight %] of the first propylene-ethylene random copolymer fraction (R-PP1).

[0225] w(PP2) is the weight fraction [in weight %] of the second propylene-ethylene random copolymer fraction (R-PP2).

[0226] C(PP1) is the comonomer content [in mol%] of the first propylene-ethylene random copolymer fraction (R-PP1).

[0227] C(PP) is the comonomer content [in mol%] of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0228] C(PP2) is the calculated comonomer content [in mol%] of the second propylene-ethylene random copolymer fraction (R-PP2).

[0229] melt flow rate

[0230] Melt flow rate (MFR) is determined according to ISO 1133 and expressed in g / 10 min. MFR indicates the flowability of a polymer and therefore its processability. A higher melt flow rate generally corresponds to a lower polymer viscosity. The MFR² of polypropylene was determined at 230°C and a load of 2.16 kg.

[0231] Calculate the melt flow rate MFR2 (230°C) of the second propylene-ethylene random copolymer fraction (PP2):

[0232]

[0233] in

[0234] w(PP1) is the weight fraction [in weight %] of the first propylene-ethylene random copolymer fraction (R-PP1).

[0235] w(PP2) is the weight fraction [in weight %] of the second propylene-ethylene random copolymer fraction (R-PP2).

[0236] MFR(PP1) is the melt flow rate MFR2 (230°C) [in g / 10min] of the first propylene-ethylene random copolymer fraction (R-PP1).

[0237] MFR(PP) is the melt flow rate MFR2 (230°C) [in g / 10min] of a single-phase propylene-ethylene random copolymer composition (R-PP).

[0238] MFR(PP2) is the calculated melt flow rate MFR2 (230°C) [in g / 10 min] of the second propylene-ethylene random copolymer fraction (R-PP2).

[0239] Xylene soluble fraction at room temperature (XCS, wt%): The amount of polymer soluble in xylene was determined at 25°C according to ISO 16152; 5th edition; 2005-07-01.

[0240] DSC analysis, melting temperature (T) m ) and heat of fusion (H f ), crystallization temperature (T) c ) and heat of crystallization (H c ): Samples of 5 to 7 mg were measured using a TAInstrument Q200 Differential Scanning Calorimeter (DSC). The DSC was operated according to ISO 11357 / Part 3 / Method C2 with heating / cooling / heating cycles at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C. Crystallization temperature (T c ) and crystalline han (H c The melting temperature (T) is determined by the cooling step, while the melting temperature (T) is determined by the melting step. m ) and enthalpy of fusion (H f The result was determined by the second heating step.

[0241] The glass transition temperature (Tg) was determined by dynamic mechanical analysis according to ISO 6721-7. The sample (40×10×1mm) was heated between -100℃ and +150℃ at a heating rate of 2℃ / min and a frequency of 1Hz. 3 Measurements were taken in torsion mode.

[0242] The flexural modulus was determined according to ISO 178 Method A (3-point bending test) on an 80 mm × 10 mm × 4 mm specimen. According to this standard, a test speed of 2 mm / min and a span length of 16 times the thickness were used. The test temperature was 23 ± 2 °C. Injection molding was performed on all materials according to ISO 19069-2 using a melt temperature of 230 °C, regardless of the material melt flow rate.

[0243] Notched impact strength (NIS)

[0244] The notched impact strength (NIS) of a simply supported beam is determined according to ISO 179 1eA using an 80×10×4mm beam at +23°C or -20°C. 3 The measurements were taken from injection-molded rod specimens prepared according to ISO 19069-2 using a melting temperature of 230°C for all materials, regardless of the melt flow rate.

[0245] The haze was measured according to ASTM D1003 on a blown film with a thickness of 50 μm, the production of which is described below.

[0246] The tensile modulus in both the longitudinal (MD) and transverse (TD) directions was determined according to ISO 527-3 at 23°C on a 50 μm thick blown film, the production of which is described below. The test was performed at a crosshead speed of 1 mm / min until the yield strength was reached, and at a speed of 10 mm / min until the specimen broke.

[0247] Dart Impact: Impact strength is determined based on dart impact (g / 50%). Dart impact is measured using ISO 7765-1 Method “A”. A dart with a hemispherical head of 38 mm diameter is dropped from a height of 0.66 m onto a thin film sample clamped in a hole. If the sample fails, the weight of the dart decreases; if the sample does not fail, the weight increases. At least 20 samples were tested. The weight that causes 50% of the samples to fail is calculated, which provides the dart impact strength (DDI) value (g). The relative DDI (g / m) can then be calculated by dividing the DDI by the thickness of the film.

[0248] Sealing start temperature (SIT)

[0249] This method is used to determine the sealing window (sealing temperature range) of a film. The procedure is similar to hot tack measurement, but compared to hot tack, the sealing range applies to the strength of the seal (or closure) after cooling (with a delay time of 30 seconds).

[0250] Sealing range = (Sealing start temperature to sealing end temperature)

[0251] The test results provide users with a quantitative and useful indication of the strength of the sealing film and show the optimal temperature range for sealing.

[0252] The temperature interval is set to 5°C by default, but when the curve shows a sharp increase or decrease in force between two temperature steps, the temperature interval can be reduced to 1°C to represent a better curve profile.

[0253] Unlike ASTM F1921-12, the test parameters for sealing pressure, cooling time, and test speed were modified. The force / temperature profile was continued until the film underwent thermal failure. In addition to the failure mode assessment described in the standard, other failure modes were used.

[0254] To characterize the material, the measured values ​​of the sealing range start temperature (SIT), the temperature at maximum force (MAX), and the sealing range end temperature were also determined.

[0255] Standard conditions:

[0256] Adjustment time: >96h

[0257] Jaw sealing dimensions: 50×5mm

[0258] Sealing opening shape: flat

[0259] Sealing coating: Niptef

[0260] Sealing temperature: ambient temperature -240℃

[0261] Sealing temperature interval: 5℃

[0262] Sealing time: 1s

[0263] Delay time: 30s

[0264] Sealing pressure: 0.4 N / mm 2 (PE); 0.67 N / mm 2 (PP)

[0265] Fixture separation rate: 42mm / s

[0266] Sealing starting force: 5N

[0267] Sample width: 25mm

[0268] result:

[0269] The output of this method is a sealing curve.

[0270] The lower limit (sealing start temperature - SIT) is the lowest sealing temperature required to achieve a sealing force ≥ 5N.

[0271] B. Example

[0272] The catalyst used in the polymerization process in all embodiments is trans-dimethylsilyl[2-methyl-4,8-di(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric-indarsen-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride, as disclosed as MC-2 in WO 2019 / 179959 A1.

[0273] For the embodiments of the present invention, the catalyst system was prepared in a manner similar to that of Comparative Catalyst System 4 (CCS4) in WO 2020 / 239602 A1, while for Comparative Example CE1, the catalyst system was prepared in a manner similar to that of Inventive Catalyst System 3 (ICS3) in WO 2020 / 239602 A1.

[0274] Examples IE1 and IE2 of the present invention and Comparative Example CE1 were polymerized according to the conditions given in Table 1 (Note: The MFR2 and C2 contents given after reactor R2 are the performance 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 pellets (i.e., R-PP) using appropriate mixing rules as given in the determination method).

[0275] CE2 to CE6 correspond to CE5 to CE9 of WO 2020 / 239602 A1, and are unimodal propylene homopolymers and copolymers polymerized using the same catalyst system as IE1 and IE2 of the present invention.

[0276] CE7 and CE8 correspond to RC2 and RC3 of WO 2022 / 043385 A1, and are bimodal propylene-ethylene copolymers polymerized using the same catalyst system as Comparative Example CE1. (Note: CE1 actually corresponds to RC1 of WO 2011 / 043385 A1)

[0277] CE9 corresponds to PP1 in WO 2016 / 162359 A1, which is a bimodal propylene-ethylene copolymer polymerized using a catalyst system containing a metallocene complex that is different from the two catalyst systems used in each of the other embodiments.

[0278] Table 1: Polymerization conditions of the propylene-ethylene random copolymer used in this invention and the comparative propylene-ethylene random copolymer

[0279]

[0280] Table 2: Performance of the propylene-ethylene random copolymer of the present invention and the performance of the comparative propylene-ethylene random copolymer

[0281]

[0282] nm - not measured, n / a - not applicable

[0283] The films in this example were produced on a laboratory-scale blown film production line at Collin 30. The BUR ratio was 1:2.5, the film thickness was 50 μm, and the melt temperature was 210 °C.

[0284] Table 3: Properties of 50 μm blown films made from the random copolymer of propylene-ethylene of the present invention and properties of 50 μm blown films made from comparative random copolymers of propylene-ethylene.

[0285]

[0286] As can be seen from Table 2 and Figure 1, the bimodal propylene-ethylene random copolymer compositions of the present invention exhibit significantly higher I(E) values ​​(for a given C2 content) than the unimodal CE4 to CE6, indicating a more random incorporation of ethylene. Similarly, the choice of catalyst also shows an effect, with CE1 and CE7 to CE9 all having lower I(E) values ​​than expected in the embodiments of the present invention with such C2 contents.

[0287] Furthermore, Figure 2 illustrates the effect of this increased randomness on the melting temperature, where the melting temperature of the embodiment of the invention is significantly lower than that of the comparative example.

[0288] As can also be seen from Table 3, the embodiments of the present invention have much higher dart impact strength and much lower haze, while maintaining similar tensile and sealing properties for a given C2 content (for IE2, the stiffness is lower, but this is expected due to the much higher C2 content).

Claims

1. A single-phase propylene-ethylene random copolymer composition (R-PP), comprising: a) A first propylene-ethylene random copolymer fraction (R-PP1) comprising 30 to 70% by weight relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP), wherein the first propylene-ethylene random copolymer fraction (R-PP1) has a content in the range of 0.1 to 5.0 mol% by quantitative analysis. 13 Ethylene content determined by C-NMR spectroscopy; b) A second propylene-ethylene random copolymer fraction (R-PP2) comprising 30 to 70% by weight relative to the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP), wherein the second propylene-ethylene random copolymer fraction (R-PP2) has a content in the range of 0.1 to 10.0 mol% by quantitative analysis. 13 Ethylene content determined by C-NMR spectroscopy; The combination of the first propylene-ethylene random copolymer fraction (R-PP1) and the second propylene-ethylene random copolymer fraction (R-PP2) constitutes at least 90% by weight of the total weight of the single-phase propylene-ethylene random copolymer composition (R-PP). The single-phase propylene-ethylene random copolymer composition (R-PP) was obtained by quantitative analysis. 13 The ethylene content, determined by C-NMR spectroscopy and expressed as mol%, was compared with that of the first propylene-ethylene random copolymer fraction (R-PP1) by quantitative analysis. 13 The ratio of ethylene content ([C2(R-PP)] / [C2(R-PP1)]) determined by C-NMR spectroscopy and expressed as mol% is greater than or equal to 1.

00. The single-phase propylene-ethylene random copolymer composition (R-PP) has a melting temperature in the range of 120 to 145°C as determined by DSC analysis and a molecular weight percentage in the range of 0.05 to 1.40 mol%. 13 The content of defects in the 2,1-region was determined by C-NMR spectroscopy. The single-phase propylene-ethylene random copolymer composition (R-PP) has a relative content I(E) of more than or equal to 70.0% of isolated ethylene sequences and block ethylene sequences, and the relative content I(E) of isolated ethylene sequences and block ethylene sequences and the C2 content C2(R-PP) of the single-phase propylene-ethylene random copolymer composition satisfy inequality (I). I(E) - 3.79[C2(R-PP)] ≥ 52.0(I), The I(E) content is defined by equation (II): (II) in I(E) is the relative content of isolated ethylene sequences and block ethylene sequences [in %]; fPEP is the mole fraction of propylene / ethylene / propylene sequence (PEP) in the sample; fPEE is the mole fraction of the propylene / ethylene / ethylene sequence (PEE) and the ethylene / ethylene / propylene sequence (EEP) in the sample; fEEE is the mole fraction of ethylene / ethylene / ethylene sequence (EEE) in the sample; All sequence concentrations are based on 13 Statistical triadic analysis of C-NMR data.

2. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 1, having a melt flow rate MFR2 in the range of 0.5 to 20 g / 10 min, determined according to ISO 1133 at 230 °C under a load of 2.16 kg.

3. The single-phase propylene-ethylene random copolymer composition (R-PP) according to claim 1, having a content in the range of 0.1 to 10.0 mol% by quantitative analysis. 13 Total ethylene content determined by C-NMR spectroscopy.

4. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 3, having a xylene cold soluble content (XCS) in the range of 0.05 to 15.0% by weight, as determined according to ISO 16152.

5. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 3, wherein a) The first propylene-ethylene random copolymer fraction (R-PP1) has a melt flow rate MFR2 in the range of 0.5 to 20 g / 10 min, as determined according to ISO 1133 at 230°C under a load of 2.16 kg, and b) The second propylene-ethylene random copolymer fraction (R-PP2) has a melt flow rate (MFR2) in the range of 0.5 to 20 g / 10 min, as determined according to ISO 1133 at 230°C under a load of 2.16 kg. The ratio of the melt flow rate MFR2 of the single-phase propylene-ethylene random copolymer composition (R-PP) measured according to ISO 1133 at 230°C and under a load of 2.16 kg and expressed in g / 10 min to the melt flow rate MFR2 of the first propylene-ethylene random copolymer fraction (R-PP1) measured according to ISO 1133 at 230°C and under a load of 2.16 kg and expressed in g / 10 min ([MFR(R-PP)] / [MFR(R-PP1)]) is less than or equal to 1.

00.

6. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 3, having a relative content (I(E)) of more than or equal to 71.0% of isolated ethylene sequences and block ethylene sequences.

7. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 3, wherein the relative content I(E) of the isolated ethylene sequence to the block ethylene sequence and the C2 content C2(R-PP) of the single-phase propylene-ethylene random copolymer composition satisfy inequality (Ia). I(E) - 3.79[C2(R-PP)] ≥ 57.0(Ia).

8. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 3, having one or more of the following properties: a) 80×10×4 mm injection molded according to EN ISO 1873-2 within the range of 500 to 1500 MPa, in accordance with ISO 178. 3 The flexural modulus measured by the test bar, and b) Between 2.0 and 20.0 kJ / m 2 Within the scope of ISO 179, use injection molding of 80×10×4 mm according to EN ISO 1873-2. 3 The notched impact strength of a simply supported beam at 23°C was determined by a test bar.

9. A method for producing a single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 8, comprising the following steps: a) Polymerize propylene and ethylene comonomer units in a first polymerization reactor in the presence of a single-active-site catalyst to produce a first polymerization mixture comprising a first propylene-ethylene random copolymer fraction (R-PP1) and the single-active-site catalyst; b) Transfer the first polymerization mixture to the second polymerization reactor; c) Polymerizing propylene and ethylene comonomer units in the second polymerization reactor in the presence of the single-active-site catalyst to produce a second polymerization mixture comprising the first propylene-ethylene random copolymer fraction (R-PP1), the second propylene-ethylene random copolymer fraction (R-PP2), and the single-active-site catalyst; d) Extract the second polymerization mixture from the second polymerization reactor; and e) The second polymerization mixture is compounded, optionally with the addition of additives, to form the single-phase propylene-ethylene random copolymer composition (R-PP).

10. The method of claim 9, wherein the single-active-center catalyst comprises: (i) Metallocene complexes having general formula (III) Equation (III) 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-, and -R'2Ge-, wherein each R' is independently a hydrogen atom or optionally contains one or more heteroatoms or fluorine atoms from groups 14 to 16 of the periodic table. 20 - A hydrocarbon group, or optionally two R' groups together, can form a ring. Each R 1 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 - hydrocarbon group, and optionally two adjacent R 1 The groups can be part of a ring containing the phenyl carbon to which they are bonded. Each R 2 Independently identical or capable of being different, and being CH2-R 8 Group, wherein R 8 C is H or a straight chain or a branched chain 1-6 -alkyl, C 3-8 -cycloalkyl, C 6-10 -Aryl, R 3 It is a straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -Alkaryl or C6-C 20 -Aryl, R 4 For C(R) 9 )3 groups, of which R 9 It is a straight-chain or branched C1-C6-alkyl group. R 5 It is aliphatic C1-C atoms that are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -Hydrocarbon group; R 6 It is aliphatic C1-C atoms that are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -hydrocarbon group; or R 5 and R 6 They can form a 5-membered saturated carbon ring, which can be optionally divided by n R... 10 Group substitution, where n is 0 to 4; Each R 10 Same or different, and can be C1-C 20 - A hydrocarbon group, or optionally a C1-C group containing one or more heteroatoms belonging to groups 14 to 16 of the periodic table. 20 -Hydrocarbon group; R 7 It is an H or a straight-chain or branched C1-C6-alkyl group or optionally surrounded by 1 to 3 R groups. 11 Group-substituted aryl or heteroaryl groups having 6 to 20 carbon atoms Each R 11 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 -Hydrocarbon group, (ii) Aluminoxane co-catalyst, and (iii) Silica carrier.

11. The single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 8, wherein the single-phase propylene-ethylene random copolymer composition (R-PP) can be obtained by the method according to claim 9 or claim 10.

12. An article comprising at least 75% by weight of a single-phase propylene-ethylene random copolymer composition (R-PP) according to any one of claims 1 to 8 or 11.

13. The article of claim 12, wherein the article is a film having one or more of the following properties: a) Tensile modulus in the longitudinal direction (MD) measured according to ISO 527-3 in the range of 500 to 2000 MPa; and / or b) Tensile modulus in the transverse (TD) direction, measured according to ISO 527-3, in the range of 500 to 2000 MPa.

14. The article of claim 12, wherein the article is a film having one or more of the following properties: a) Haze values ​​measured according to ASTM D1003 in the range of 0.0% to 10.0%, and b) Dart impact strength (DDI) measured according to ASTM D1709 Method A in the range of 40 to 100 g.

15. The article of any one of claims 12 to 14, wherein the article is a blown film.

16. The article of any one of claims 12 to 14, wherein the article is a film having a seal initiation temperature (SIT) in the range of 105 to 130°C.

17. The article of claim 16, wherein the difference between the melting temperature of the single-phase propylene-ethylene random copolymer composition (R-PP) as determined by DSC analysis and the sealing initiation temperature (SIT) of the film is in the range of 10 to 25°C.

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