Polyethylene pipe with improved high-temperature hydrostatic performance

Abstract

The present invention relates to a base resin (B) comprising a polyethylene composition (PC), wherein the polyethylene composition (PC) comprises a first ethylene polymer (B1) and a second ethylene polymer (B2) having a weight average molecular weight higher than that of the first ethylene polymer (B1). Furthermore, the present invention relates to a pipe comprising the base resin (B).

Description

Technology Field

[0001] The present invention relates to a base resin (B) comprising a polyethylene composition (PC), wherein the polyethylene composition (PC) comprises a first ethylene polymer (B1) and a second ethylene polymer (B2) having a weight average molecular weight higher than that of the first ethylene polymer (B1). Furthermore, the present invention relates to a pipe comprising the base resin (B). Background Technology

[0002] Polyethylene pipes are widely used for water and gas transportation due to their various advantages over other materials such as steel, concrete, or fiber-reinforced plastics. The main advantages of plastic pipes are that they are corrosion-resistant, flexible, and possess excellent mechanical strength. Polyethylene pipes are generally used in a temperature range of 0°C to 50°C. To use these plastic pipes in high-temperature environments exceeding 20°C, the rated capacity of the pipes must be reduced in accordance with ISO 13761. Reducing the rated capacity requires increasing the pipe thickness to withstand these operating conditions. Therefore, to reduce pipe thickness and material consumption, polyethylene with a higher Minimum Required Strength (MRS) at 20°C is required.

[0003] Since the characteristics of polyethylene resin—namely, mechanical strength and excellent long-term strength (stress crack resistance)—are contradictory, manufacturing a product that possesses both high MRS and excellent mechanical strength is a difficult task.

[0004] Therefore, recent developments in PE100+ grades have focused on improving the balance between short-term and long-term properties. Short-term properties are measured through hydrostatic pressure tests (HPT) of pipes at various stress levels at 20°C and 80°C. Additionally, long-term stress cracking resistance is measured in pipes through hydrostatic pressure tests of notched pipes. Similarly, accelerated stress cracking resistance measurement tests, such as strain hardening tests, have been developed to evaluate the long-term resistance of pipe resins.

[0005] To verify whether HDPE meets PE100 certification, various quality control tests are performed on pipes produced from this resin. The notched pipe test is most commonly used to measure stress cracking resistance. Additionally, short-term pressure resistance is measured via a hydrostatic test at 80°C. To obtain PE100 or PE100RC certification, the minimum time to pipe failure criteria must be met in both tests. However, the results of these two tests are inversely related. For example, if the comonomer content of the polymer increases (i.e., if the density decreases), the notched pipe test results will improve, but the HPT test results will deteriorate. Conversely, if the polymer undergoes the opposite change—that is, if the comonomer content decreases, implying an increase in density—the notched pipe test results will worsen, while the HPT results will improve.

[0006] Therefore, a balance must be struck between the two test results while meeting the requirements of PE100 or PE100RC. Although it is possible to design a polymer that satisfies both requirements, the production range of such polymers becomes narrow.

[0007] Therefore, the objective of the present invention is to provide a polyethylene composition suitable for manufacturing pipes that meets PE100 or PE100RC requirements while maintaining high levels in both Notch Pipe Test (NPT) and Hydrostatic Test (HPT) results.

[0008] Accordingly, the present invention is based on the total weight of the base resin (B).

[0009] i) 30.0 to 70.0 weight% of a first ethylene polymer (B1), which is an ethylene homopolymer or a copolymer of ethylene and C3-C8α-olefin, and

[0010] ii) 30.0 to 70.0 weight% of a second ethylene polymer (B2) which is a copolymer of ethylene and C3-C8α-olefin and has a lower density than the first copolymer (B1).

[0011] This relates to a base resin (B) containing

[0012] According to one embodiment of the present invention,

[0013] i) The total amount of C3-C8α-olefin monomeric unit C in the base resin (B) is in the range of 0.1 to 0.7 mol-% and / or

[0014] ii) The base balance (B) satisfies inequality (I):

[0015]

[0016] In inequality (I), MWD is the molecular weight distribution (Mw / Mn) of the base resin (B), and C is the total amount [mol-%] of C3-C8α-olefin monomeric units in the base resin (B).

[0017] According to another embodiment of the present invention, the base resin (B) has an amount of hexane solution of 1.30 weight% or less based on the total weight of the base resin (B) when determined according to the method given in the measurement method.

[0018] According to another embodiment of the present invention, the first ethylene polymer (B1) is 960 to 980 kg / m³ when determined according to ISO 1183-1:2004. 3 It has a density in the range and / or a molecular weight distribution (Mw / Mn) of 29.4 or less.

[0019] According to another embodiment of the present invention, the first ethylene polymer (B1) is an ethylene homopolymer, and the second copolymer (B2) is a copolymer of ethylene and 1-hexene.

[0020] According to one embodiment of the present invention, a base resin (B) is obtained by a method comprising the step of reacting a support in the presence of a Ziegler-Natta catalyst (ZN), and at least the surface of the support is

[0021] Magnesium halide compound having chemical formula (1):

[0022]

[0023] In chemical formula (1), R is C l -C 20 alkyl or C7-C 26 It is aralkyl, each identical or different X is a halogen, and n is an integer of 1 or 2,

[0024] Alkyl metal halide compound having chemical formula (2):

[0025]

[0026] In chemical formula (2), M is B or Al, and each is the same or different R 1 C l -C 10 Alkyl, and each identical or different X 1 is a halogen, and when m1 is 1, n1 is 1 or 2, and when m1 is 2, n1 is an integer from 1 to 5,

[0027] A magnesium composition containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide - the magnesium composition has empirical formula (3) -:

[0028]

[0029] In the empirical formula (3), each identical or different R 2 is C1-C 20 alkyl, and each identical or different R 3 C1-C 20 C1-C containing alkyl or heteroatoms 20 It is alkyl, and n2 is 0.01 to 1.99, and

[0030] Titanium halide compound having chemical formula (4):

[0031]

[0032] In chemical formula (4), each identical or different R 4 is C1-C 20 Alkyl, and each identical or different X 2 is a halogen, n3 is an integer of 0 or 1 to 3, and Ti is tetravalent titanium.

[0033] Includes

[0034] Furthermore, the present invention

[0035] a) Based on the total weight of the polyethylene composition (PC), at least 90 weight% of the base resin (B) as described above,

[0036] b) Pigment (P), and

[0037] c) Optional additive (AD)

[0038] This relates to a polyethylene composition (PC) containing

[0039] According to one embodiment of the present invention, the polyethylene composition (PC) is

[0040] i) 957 to 965 kg / m³ when determined according to ISO 1183-1:2004 3 Density of the range, and

[0041] ii) Flow velocity ratio FRR in the range of 27 to 36 21 / 5 = MFR 21 / MFR5- MFR5 is the melt flow rate determined according to ISO 1133 at a temperature of 190°C and a load of 5.0 kg, and MFR 21 is the melt flow rate determined according to ISO 1133 at a temperature of 190°C and a load of 21.6 kg.

[0042] has

[0043] According to another embodiment of the present invention, the pigment (P) is selected from the group consisting of carbon black, molybdenum orange, and cadmium orange.

[0044] According to another embodiment of the present invention, the polyethylene composition (PC) has a melt flow rate MFR5 (5.0 kg, 190°C) of less than 2.0 g / 10 min when determined according to ISO 1133.

[0045] According to another embodiment of the present invention, the polyethylene composition (PC) has a melt flow rate MFR in the range of 0.5 to 12.0 g / 10 min when determined according to ISO 1133. 21 It has (21.6 kg, 190℃).

[0046] According to another embodiment of the present invention, the polyethylene composition (PC) has a strain hardening modulus in the range of 50.0 to 85.0 MPa.

[0047] The present invention also relates to a pipe comprising at least 90 weight percent of the aforementioned polyethylene composition (PC).

[0048] According to one embodiment of the present invention, the pipe satisfies inequality (II) and / or inequality (III):

[0049]

[0050] In inequality (II) and / or inequality (III),

[0051] HPT 5.9 is the hydrostatic pressure test value [h] of the pipe determined at a pressure of 5.9 MPa and a temperature of 80℃, and

[0052] HPT 5.7 is the hydrostatic pressure test value [h] of the pipe determined at a pressure of 5.7 MPa and a temperature of 80℃, and

[0053] SH is the strain hardening coefficient [MPa] of the polyethylene composition (PC).

[0054] According to another embodiment of the present invention, the pipe is a fluid pipe, preferably an oil or water pipe.

[0055] It is especially desirable that it be a pressure pipe.

[0056] Furthermore, the present invention

[0057] a) Step of manufacturing a base resin (B) in a sequential process comprising at least two reactors:

[0058] i) A step of polymerizing ethylene and optionally C3-C8α-olefin in a first reactor (R1) to obtain a first ethylene polymer (B1) satisfying inequality (IV):

[0059]

[0060] In inequality (IV),

[0061] H2 / C2(R1) is the molar ratio [mol / kmol] of hydrogen and ethylene in the first reactor (R1), and

[0062] MFR2(R1) is the melt flow rate MFR2 (2.16 kg, 190°C) of the first ethylene polymer (B1) obtained in the first reactor (R1) when determined according to ISO 1133,

[0063] ii) A step of transferring the first ethylene polymer (B1) obtained in the first reactor (R1) to the second reactor (R2),

[0064] iii) A step of polymerizing ethylene and C3-C8α-olefin in the presence of a first ethylene polymer (B1) in a second reactor (R2) to obtain a second ethylene polymer (B2) - the first ethylene polymer (B1) and the second ethylene polymer (B2) together form a base resin (B) satisfying inequality (V) -:

[0065]

[0066] In the inequality (V),

[0067] H2 / C2(R2) is the molar ratio of hydrogen and ethylene in the second reactor (R2) [mol / kmol], and

[0068] MFR5(R2) is the melt flow rate MFR5 (5.0 kg, 190℃) of the base resin (B) when determined according to ISO 1133,

[0069] b) A step of obtaining a polyethylene composition (PC) by combining a base resin with a pigment (P) and optionally an additive (AD), and

[0070] c) Step of obtaining a pipe by extruding a polyethylene composition (PC) through a suitable die.

[0071] This relates to a method for manufacturing the aforementioned pipe, including

[0072] The present invention is described in more detail below. Specific details for implementing the invention

[0073] Base resin (B)

[0074] As described above, the present invention relates to a polyethylene base resin (B) suitable for manufacturing high-pressure pipes.

[0075] Based on the total weight of the base resin (B), the base resin (B) comprises 30.0 to 70.0 weight% of a first ethylene polymer (B1), which is an ethylene homopolymer or a copolymer of ethylene and C3-C8α-olefin, and 30.0 to 70.0 weight% of a second ethylene polymer (B2), which is a copolymer of ethylene and C3-C8α-olefin and has a lower density than the first copolymer (B1).

[0076] Preferably, the base resin (B) comprises, based on the total weight of the base resin (B), 40.0 to 60.0 weight% of a first ethylene polymer (B1), more preferably 42.0 to 58.0 weight%, more preferably 44.0 to 56.0 weight%, e.g. 47.0 to 53.0 weight%, and 40.0 to 60.0 weight% of a second ethylene polymer (B2), more preferably 42.0 to 58.0 weight%, more preferably 44.0 to 56.0 weight%, e.g. 47.0 to 53.0 weight%.

[0077] In addition, it is preferable that the molecular weight of the first ethylene polymer (B1) is lower than the molecular weight of the second ethylene polymer (B2). Accordingly, it is preferable that the first ethylene polymer (B1) has a higher melt flow rate MFR2 (190°C, 2.16 kg) than the second ethylene polymer (B2) when determined according to ISO 1133. In addition, it is preferable that the first ethylene polymer (B1) has a higher melt flow rate MFR than the second ethylene polymer (B2) when determined according to ISO 1133. 21 It is desirable to have (190℃, 21.6 kg).

[0078] The first ethylene polymer (B1) may be an ethylene homopolymer or an ethylene copolymer, and the second ethylene polymer (B2) is an ethylene copolymer.

[0079] 'Ethylene homopolymer' refers to a polymer essentially composed of ethylene monomer units. Due to the requirements of large-scale polymerization, the ethylene homopolymer may contain trace amounts of comonomer units, the trace amount being less than 0.1 mol% of the ethylene homopolymer, preferably less than 0.05 mol%, most preferably less than 0.01 mol%.

[0080] A polymer is referred to as an 'ethylene copolymer' if the polymer is derived from an ethylene monomer unit and at least one alpha-olefin comonomer. The alpha-olefin comonomer is preferably selected from alpha-olefin comonomers having 4 to 8 carbon atoms, more preferably 4 to 6 carbon atoms. Suitable alpha-olefin comonomer species are 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, or mixtures thereof. 1-butene and 1-hexene are preferred. 1-hexene is most preferred.

[0081] Base resin (B) The total amount of my C3-C8α-olefin monomer units is preferably in the range of 0.1 to 0.7 mol%, more preferably in the range of 0.2 to 0.6 mol%, and even more preferably in the range of 0.3 to 0.5 mol%.

[0082] When both the first ethylene polymer (B1) and the second ethylene polymer (B2) are ethylene copolymers, the comonomers may be the same or different. Accordingly, the first ethylene polymer (B1) and the second ethylene polymer (B2) may independently contain a comonomer selected from alpha-olefin comonomers having 3 to 8 carbon atoms, more preferably 4 to 8. Suitable alpha-olefin comonomer species are 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, or mixtures thereof. 1-butene and 1-hexene are preferred. 1-hexene is most preferred. Preferably, the first ethylene polymer (B1) and the second ethylene polymer (B2) contain the same comonomer. Accordingly, the first ethylene polymer (B1) and the second ethylene polymer (B2) preferably contain a comonomer selected from alpha-olefin comonomers having 3 to 8 carbon atoms, more preferably 4 to 8 carbon atoms. Suitable alpha-olefin comonomer species are 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, or mixtures thereof. 1-butene and 1-hexene are preferred. Most preferably, the first ethylene polymer (B1) and the second ethylene polymer (B2) are copolymers of ethylene and 1-hexene.

[0083] However, it is preferable that the first ethylene polymer (B1) be an ethylene homopolymer.

[0084] In addition, the first ethylene polymer (B1) is 960 to 980 kg / m³ when determined according to ISO 1183-1:2004. 3 Range, more preferably 965 to 976 kg / m² 3 Range, more preferably 968 to 975 kg / m² 3 Range, e.g., 970 to 974 kg / m² 3 It is desirable to have a density within a range.

[0085] When determined according to ISO 1133, the melt flow rate MFR2 (190°C, 2.16 kg) of the first ethylene polymer (B1) is preferably in the range of 100 to 350 g / 10 min, more preferably in the range of 120 to 330 g / 10 min, more preferably in the range of 130 to 320 g / 10 min, for example in the range of 150 to 316 g / 10 min.

[0086] The second ethylene polymer (B2) is an ethylene copolymer.

[0087] In particular, the second ethylene polymer (B2) is a copolymer of ethylene and a C3-C8α-olefin. More preferably, the second ethylene polymer (B2) is a copolymer of ethylene and a C4-C6α-olefin. More preferably, the second ethylene polymer (B2) is a copolymer of ethylene and 1-butene or 1-hexene. In particular, it is preferable that the second ethylene polymer (B2) is a copolymer of ethylene and 1-hexene.

[0088] Preferably, the second ethylene polymer (B2) is 940 to 955 kg / m³ when determined according to ISO 1183-1:2004. 3 Range, more preferably 943 to 953 kg / m² 3 Range, more preferably 945 to 952 kg / m² 3 Range, e.g., 949 to 951 kg / m² 3 It has a density of the range.

[0089] The molecular weight distribution (Mw / Mn) of the base resin (B) is preferably 29.4 or less, more preferably in the range of 19.0 to 29.2, and more preferably in the range of 22.0 to 29.0.

[0090] In addition to the preceding paragraph or alternatively, the base resin (B) preferably satisfies inequality (I), more preferably inequality (Ia), and more preferably inequality (Ib):

[0091]

[0092] In the inequality, MWD is the molecular weight distribution (Mw / Mn) of the base resin (B), and C is the total amount [mol%] of C3-C8α-olefin monomer units in the base resin (B).

[0093] In addition, the base resin (B) preferably has an amount of hexane solution of 1.30 weight% or less, more preferably 1.20 weight% or less, and more preferably 1.18 weight% or less based on the total weight of the base resin (B) when determined according to the method given in the measurement method.

[0094] The base resin (B) is preferably manufactured through a multi-step process in the presence of a Ziegler-Natta catalyst. This process is described in more detail below.

[0095] Polyethylene composition (PC)

[0096] Furthermore, the present invention relates to a polyethylene composition (PC) comprising at least 90.0 weight% of a base resin (B) as described above and a pigment (P).

[0097] Accordingly, the term 'base resin' refers to the polymer portion of a polyethylene composition (PC) that is free of pigments such as carbon black. Those skilled in the art will understand that the measurement of base resin requires the presence of a stabilizer. The base resin according to the present invention refers to a polymer derived from at least 50 mol% of ethylene monomer units and additional comonomer units.

[0098] In addition to the base resin, additives (ADs) commonly used in polyolefins, such as stabilizers (e.g., antioxidants), antacids and / or UV blockers, antistatic agents, and utilization agents (e.g., processing aids), may be present in the polyethylene composition. Preferably, the amount of these additives is 10% by weight or less, more preferably 8% by weight or less, and most preferably 5% by weight or less, based on the total weight of the polyethylene composition (PC).

[0099] Preferably, the polyethylene composition (PC) contains 8% or less by weight of the total composition, more preferably 1% to 4% by weight of pigment (P).

[0100] The pigment (P) is preferably selected from the group consisting of carbon black, molybdenum orange, and cadmium orange.

[0101] The additive content is understood to include any carrier polymer used to introduce the additive or pigment (if present) into the polyethylene composition (PC), namely, a masterbatch carrier polymer. An example of such a carrier polymer would be high-density polyethylene in powder form.

[0102] More preferably, the amount of additives different from the pigment (P) and the masterbatch carrier polymer is 1 weight% or less, more preferably 0.5 weight% or less.

[0103] Preferably, the polyethylene composition (PC) according to the present invention has a melt flow rate MFR5 (190°C, 5.0 kg) in the range of, for example, 0.1 to 0.4 g / 10 min, less than 2.0 g / 10 min, more preferably less than 1.5 g / 10 min, more preferably less than 1.0 g / 10 min when determined according to ISO 1133.

[0104] In addition to the preceding paragraph, or alternatively, the polyethylene composition (PC) has a melt flow rate MFR in the range of 0.5 to 12.0 g / 10 min, more preferably in the range of 2.0 to 10.0 g / 10 min, more preferably in the range of 3.5 to 9.0 g / 10 min, for example in the range of 4.5 to 8.2 g / 10 min, when determined according to ISO 1133. 21 It has (190℃, 21.6 kg).

[0105] Therefore, the polyethylene composition (PC) is MFR for MFR5 21 The flow velocity ratio FRR 21 / 5It has a range of 20.0 to 40.0, more preferably 23.0 to 38.0, more preferably 28.0 to 36.0, for example 30.0 to 35.0.

[0106] Preferably, the polyethylene composition (PC) according to the present invention has a value of 950 to 965 kg / m³ when determined according to ISO 1183-1:2004. 3 Range, more preferably 955 to 964 kg / m² 3 Range, more preferably 957 to 963 kg / m² 3 Range, e.g., 959 to 963 kg / m² 3 It has a density of the range.

[0107] The polyethylene composition (PC) according to the present invention is also characterized by strain hardening behavior. Preferably, the polyethylene composition (PC) has a strain hardening coefficient in the range of 50.0 to 85.0 MPa, more preferably in the range of 52.0 to 83.0 MPa, more preferably in the range of 54.0 to 81.0 MPa, for example in the range of 56.0 to 80.0 MPa.

[0108] pipe

[0109] The present invention relates to a pipe comprising a polyethylene composition (PC) as described above.

[0110] According to the present invention, the pipe satisfies inequality (I) and / or inequality (II):

[0111]

[0112] In inequality (I) and / or inequality (II),

[0113] HPT 5.9 is the hydrostatic pressure test value [h] of the pipe determined at a pressure of 5.9 MPa and a temperature of 80℃, and

[0114] HPT 5.7is the hydrostatic pressure test value [h] of the pipe determined at a pressure of 5.7 MPa and a temperature of 80℃, and

[0115] SH is the strain hardening coefficient [MPa] of the polyethylene composition (PC).

[0116] Preferably, the hydrostatic pressure test value HPT of the pipe is determined at a pressure of 5.9 MPa and a temperature of 80°C. 5.9 It is at least 200 hours, more preferably in the range of 200 to 6000 hours, more preferably in the range of 400 to 5500 hours, for example in the range of 500 to 5100 hours.

[0117] In addition, or as an alternative to the preceding paragraph, the hydrostatic test value HPT of the pipe when determined at a pressure of 5.7 MPa and a temperature of 80°C 5.7 It is preferable that the duration be at least 1,000 hours, more preferably in the range of 1,000 to 6,100 hours, more preferably in the range of 1,500 to 5,800 hours, for example in the range of 2,000 to 4,700 hours.

[0118] In addition, when determined at a pressure of 4.6 MPa and a temperature of 80°C, the notched pipe test value (NPT) is preferably at least 800 hours, more preferably in the range of 800 hours to 7000 hours, more preferably in the range of 1000 hours to 6800 hours, for example in the range of 1100 hours to 6500 hours.

[0119] The pipe according to the present invention preferably comprises at least 90.0 weight%, more preferably at least 95.0 weight%, more preferably 98 weight%, for example 99.0 weight% of the aforementioned polyethylene composition (PC). In particular, the pipe according to the present invention preferably comprises the aforementioned polyethylene composition (PC).

[0120] Preferably, the pipe according to the present invention is a fluid pipe. In particular, it is preferably an oil or water pipe.

[0121] In addition, it is desirable that the pipe be a pressure pipe.

[0122] method

[0123] Furthermore, the present invention

[0124] a) Step of manufacturing a base resin (B) in a sequential process comprising at least two reactors:

[0125] i) A step of polymerizing ethylene and optionally C3-C8α-olefin in a first reactor (R1) to obtain a first ethylene polymer (B1) satisfying inequality (IV):

[0126]

[0127] In inequality (IV),

[0128] H2 / C2(R1) is the molar ratio [mol / kmol] of hydrogen and ethylene in the first reactor (R1), and

[0129] MFR2(R1) is the melt flow rate MFR2 (2.16 kg, 190°C) of the first ethylene polymer (B1) obtained in the first reactor (R1) when determined according to ISO 1133,

[0130] ii) A step of transferring the first ethylene polymer (B1) obtained in the first reactor (R1) to the second reactor (R2),

[0131] iii) A step of polymerizing ethylene and C3-C8α-olefin in the presence of a first ethylene polymer (B1) in a second reactor (R2) to obtain a second ethylene polymer (B2) - the first ethylene polymer (B1) and the second ethylene polymer (B2) together form a base resin (B) satisfying inequality (IV) -:

[0132]

[0133] In the inequality (V),

[0134] H2 / C2(R2) is the molar ratio of hydrogen and ethylene in the second reactor (R2) [mol / kmol], and

[0135] MFR5(R2) is the melt flow rate MFR5 (5.0 kg, 190℃) of the base resin (B) when determined according to ISO 1133,

[0136] b) A step of obtaining a polyethylene composition (PC) by combining a base resin with a pigment (P) and optionally an additive (AD), and

[0137] c) Step of obtaining a pipe by extruding a polyethylene composition (PC) through a suitable die

[0138] This relates to a method for manufacturing a pipe as described above, including

[0139] According to step a) of the method of the present invention, the base resin (B) is manufactured through a sequential process comprising at least two reactors.

[0140] In particular, the base resin (B) of the present invention is preferably produced by polymerizing or copolymerizing ethylene in a reactor cascade formed by at least a first reactor (R1) and at least a second reactor (R2), wherein preferably the first reactor (R1) is a slurry reactor (SR) and the second reactor (R2) is a gas phase reactor (GPR).

[0141] The multi-stage process is described below.

[0142] The first polymerization step takes place in the first reactor (R1). The first reactor (R1) is preferably the first slurry-phase reactor (SR), and more preferably the first loop reactor (LR).

[0143] These reactors include continuous stirred tank reactors and loop reactors. It is particularly desirable to carry out polymerization in a loop reactor. In such reactors, the slurry is circulated at high speed along a closed pipe by using a circulation pump. Loop reactors are generally known in the art, and examples are given, for instance, in US-A-4,582,816, US-A-3,405,109, US-A-3,324,093, EP-A-479 186 and US-A-5,391,654.

[0144] The temperature of the first reactor (R1) is generally 50°C to 115°C, preferably 60°C to 110°C, particularly 70°C to 100°C. The pressure is generally 1 to 150 bar, preferably 1 to 100 bar.

[0145] Occasionally, it is advantageous to perform the first loop polymerization at temperatures and pressures exceeding the critical temperature and pressure of the fluid mixture. Such operations are described in US-A-5,391,654. In such operations, the temperature is typically at least 85°C, preferably at least 90°C. Furthermore, the temperature is typically 110°C or lower, preferably 105°C or lower. The pressure under these conditions is typically at least 40 bar, preferably at least 50 bar. Furthermore, the pressure is typically 150 bar or lower, preferably 100 bar or lower. In a preferred embodiment, the first and / or second polymerization steps are performed under supercritical conditions where the reaction temperature and reaction pressure are higher than the equivalent critical point of the mixture formed by the hydrocarbon medium, monomer, hydrogen, and optional comonomer, and the polymerization temperature is lower than the melting point of the polymer being formed.

[0146] It is preferable that the difference in reaction temperature between the first and second reactors be 10% or less, preferably 0% to 9%.

[0147] In addition, the difference in reaction pressure between the first and second reactors is preferably 15% or less, preferably 0% to 13%. Preferably, the pressure in the first reactor (R1) is higher than the pressure in the second reactor (R2).

[0148] In a first reactor (R1), a first intermediate material is obtained that comprises, preferably, the first ethylene polymer (B1) and optionally the prepolymer fraction. The first intermediate material is obtained in the first reactor (R1) by polymerizing ethylene in the presence of optionally the prepolymer fraction, thereby obtaining the first ethylene polymer (B1).

[0149] The first intermediate material, which optionally comprises a first ethylene polymer (B1) together with a prepolymer fraction and preferably consists of the same, has a melt flow rate MFR2 (190°C, 2.16 kg) in the range of 100 to 350 g / 10 min, more preferably 120 to 330 g / 10 min, more preferably 130 to 320 g / 10 min, for example 150 to 316 g / 10 min, as determined according to ISO 1133.

[0150] To adjust the MFR2 of the first intermediate material, preferably hydrogen is introduced into the first reactor (R1) to polymerize ethylene and obtain the first ethylene polymer (B1). The amount of hydrogen supplied is preferably adjusted to the amount of ethylene supplied so that the hydrogen-to-ethylene ratio in the first reactor (R1) is 300 to 700 mol / kmol, more preferably 400 to 650 mol / kmol, and most preferably 470 to 630 mol / kmol.

[0151] In particular, ethylene is polymerized in the first reactor (R1) to obtain a first ethylene polymer (B1) satisfying inequality (IV):

[0152]

[0153] In inequality (IV),

[0154] H2 / C2(R1) is the molar ratio [mol / kmol] of hydrogen and ethylene in the first reactor (R1), and

[0155] MFR2(R1) is the melt flow rate MFR2 (2.16 kg, 190°C) of the first ethylene polymer (B1) obtained in the first reactor (R1) when determined according to ISO 1133.

[0156] The first ethylene polymer (B1) produced in the first reactor (R1) may be an ethylene homopolymer or a copolymer. It is preferable that the first ethylene polymer (B1) be an ethylene homopolymer.

[0157] However, when polymerizing the copolymer, the comonomer is preferably selected from the group comprising 1-butenel, 1-hexenel, 4-methyl-1-pentene, 1-octene, or a mixture thereof, and 1-hexene is particularly preferred. In a preferred embodiment, the ethylene homopolymer is polymerized in such a way that no comonomer is supplied to the first polymerization step in the first reactor (R1).

[0158] The residence time and polymerization temperature in the first reactor (R1) are adjusted to polymerize ethylene and optionally a comonomer to obtain an ethylene homopolymer or copolymer, which is generally 40 to 60 weight percent, preferably 45 to 50 weight percent, of the total base resin, a first ethylene polymer (B1).

[0159] In addition, the first ethylene polymer (B1) in the process is as defined above for the base resin (B) of the present invention.

[0160] The first intermediate material obtained in the first reactor (R1) — preferably comprising the first ethylene polymer (B1) and optionally a prepolymer fraction — is subsequently transferred to the second reactor (R2).

[0161] The slurry may be withdrawn from the first reactor (R1) continuously or intermittently. The slurry withdrawn from the first polymerization contains a first intermediate material.

[0162] A preferred method of intermittent discharge is the use of a settling leg in which the slurry is concentrated before the batch of concentrated slurry is discharged from the reactor. The use of a settling leg is disclosed in particular in US-A-3,374,211, US-A-3,242,150, and EP-A-1 310 295. Continuous discharge is disclosed in particular in EP-A-891 990, EP-A-1 415 999, EP-A-1 591 460, and WO-A-2007 / 025640. Continuous discharge is advantageously combined with a suitable concentration method as disclosed in EP-A-1 415 999 and EP-A-1 591 460.

[0163] Settling legs are used to concentrate the slurry discharged from the reactor. Therefore, the discharge stream contains, on average, more polymer per unit volume than the slurry inside the reactor. This has the advantage of lower equipment costs because less liquid needs to be recirculated back into the reactor. In commercial-scale plants, the fluid discharged with the polymer is evaporated in a flash vessel, from where it is compressed by a compressor and recirculated back into the slurry-phase reactor.

[0164] However, settling legs discharge the polymer intermittently. This causes pressure and other variables in the reactor to fluctuate depending on the discharge period. Additionally, discharge capacity is limited and depends on the size and number of settling legs. To overcome these disadvantages, continuous discharge is often desirable.

[0165] Meanwhile, continuous discharge has the problem of typically discharging the polymer at the same concentration as that present in the reactor. To reduce the amount of hydrocarbon to be compressed, the continuous outlet is advantageously combined with a suitable concentration device, such as a hydrocyclone or sieve, as disclosed in EP-A-1 415 999 and EP-A-1 591 460. Subsequently, the polymer-rich stream is directed to a flash, flash vessel, and the polymer-lean stream is returned directly to the reactor.

[0166] The first intermediate material obtained in the first reactor (R1)—preferably comprising, and preferably composed of, the first ethylene polymer (B1) together with the prepolymer fraction, optionally—is transferred to a flash vessel for a purging step and then transferred to the second reactor (R2). In the flash vessel, hydrocarbons are substantially removed from the polymer. Optionally, but less preferably, the first intermediate material is transferred directly to the second reactor (R2).

[0167] The second polymerization step is carried out in the second reactor (R2). The second reactor (R2) is a gas phase reactor (GPR), more preferably a fluidized bed gas phase reactor.

[0168] In a fluidized bed gas phase reactor, olefins are polymerized in an upward-moving gas stream in the presence of a polymerization catalyst. The reactor typically contains a fluidized bed comprising growing polymer particles containing an active catalyst placed over a fluidization grid. The polymer bed is fluidized with the help of a fluidizing gas comprising olefin monomers, eventually comonomer(s), eventually a chain growth control agent or chain transfer agent, such as hydrogen, and eventually an inert gas. The inert gas may be the same or different from the inert gas used in a slurry phase reactor. The fluidizing gas is introduced into the inlet chamber at the bottom of the reactor. To ensure that the gas flow is uniformly distributed across the cross-sectional surface area of ​​the inlet chamber, a flow dividing element may be fitted to the inlet pipe as known in the art, e.g., US-A-4,933,149 and EP-A-684 871.

[0169] The gas flow from the inlet chamber passes upward through the fluidization grid to the fluidization bed. The purpose of the fluidization grid is to uniformly divide the gas flow across the cross-sectional area of ​​the bed. Occasionally, the fluidization grid may be arranged to construct the gas stream to sweep along the reactor wall, as disclosed in WO-A-2005 / 087261. Other types of fluidization grids are disclosed specifically in US-A-4,578,879, EP 600 414, and EP-A-721 798. An overview is given in Geldart and Bayens: The Design of Distributors for Gas-fluidised Beds, Powder Technology, Vol. 42, 1985.

[0170] The fluidizing gas passes through the fluidization bed. The supercritical velocity of the fluidizing gas must be higher than the minimum fluidization velocity of the particles contained in the fluidization bed, unless fluidization occurs otherwise. Meanwhile, since the entire bed will be filled with the fluidizing gas, the velocity of the gas must be lower than the onset velocity of pneumatic transport. When particle characteristics are known, the minimum fluidization velocity and the onset velocity of pneumatic transport can be calculated by using common engineering practices. An overview is given specifically in Geldart: Gas Fluidization Technology, J. Wiley & Sons, 1996.

[0171] When a bed containing an active catalyst comes into contact with a fluidizing gas, the reactive components of the gas, such as monomers and chain reaction transporters, react in the presence of the catalyst to produce a polymer product. At the same time, the gas is heated by the heat of reaction.

[0172] Subsequently, unreacted fluidized gas is removed from the top of the reactor, compressed, and recirculated to the reactor's inlet chamber. Before entering the reactor, fresh reactants are introduced into the fluidized gas stream to compensate for losses caused by the reaction and product discharge. Generally, it is known to analyze the composition of the fluidized gas and introduce gas components to maintain a constant composition. The actual composition is determined by the desired characteristics of the products and catalysts used in the polymerization.

[0173] Subsequently, the gas is cooled in a heat exchanger to remove the heat of reaction. The gas is cooled to a temperature lower than the bed temperature to prevent the bed from being heated due to the reaction. It is possible to cool the gas to a temperature at which a portion of it is condensed. When a liquid droplet enters the reaction zone, the droplet vaporizes. Subsequently, the heat of vaporization contributes to the removal of the heat of reaction. This type of operation is called the condensation mode, and variations thereof are disclosed in particular in WO-A-2007 / 025640, US-A-4,543,399, EP-A-699 213, and WO-A-94 / 25495. Additionally, as disclosed in EP-A-696 293, it is possible to add a condensing agent to the recirculated gas stream. The condensing agent is a non-polymerizable component, such as propane, n-pentane, isopentane, n-butane, or isobutane, which is at least partially condensed in a cooler.

[0174] The polymeric product may be discharged from the gas phase reactor continuously or intermittently. The polymeric product discharged from the gas phase reactor of the third polymerization step is a base resin as shown in FIG. 1. A combination of these methods may also be used. Continuous discharge is disclosed in particular in WO-A-00 / 29452. Intermittent discharge is disclosed in particular in US-A-4,621,952, EP-A-188 125, EP-A-250 169 and EP-A-579 426.

[0175] At least one upper part of the gas phase reactor may include a so-called disengagement zone. In this zone, the diameter of the reactor is increased to reduce the gas velocity and cause particles carried from the bed along with the fluidizing gas to settle back into the bed.

[0176] Bed levels can be observed by different techniques known in the art. For example, the pressure difference between the bottom of the reactor and a specific height of the bed can be recorded over the entire length of the reactor, and the bed level can be calculated based on the pressure difference value. This calculation yields a time-averaged level. Additionally, it is possible to use ultrasonic sensors or radioactive sensors. By these methods, an immediate level can be obtained, which is then, of course, averaged over time to obtain a time-averaged bed level.

[0177] Additionally, antistatic agent(s) may be introduced into at least one gas-phase reactor if necessary. Suitable antistatic agents and methods of using them are disclosed in particular in US-A-5,026,795, US-A-4,803,251, US-A-4,532,311, US-A-4,855,370 and EP-A-560 035. These are typically polar compounds, and in particular include water, ketones, aldehydes, and alcohols.

[0178] The reactor may include a mechanical shaker to further facilitate mixing within the fluidization bed. An example of a suitable shaker design is given in EP-A-707 513.

[0179] In a second reactor (R2), a base resin is obtained that comprises, preferably, a first ethylene polymer (B1) and a second ethylene polymer (B2) together with a prepolymer fraction. The base resin is obtained by polymerizing the second ethylene polymer (B2) together with the prepolymer fraction in the presence of the first ethylene polymer (B1).

[0180] The temperature in the gas-phase reactor is typically at least 70°C, preferably at least 80°C. The temperature is typically 105°C or lower, preferably 95°C or lower. The pressure is typically at least 10 bar, preferably at least 15 bar, but typically 30 bar or lower, preferably 25 bar or lower.

[0181] The base resin is obtained by selectively polymerizing ethylene and a C3-C8α-olefin, preferably 1-butene or 1-hexene, more preferably 1-hexene, with a prepolymer fraction in the presence of a first ethylene polymer (B1) in a second reactor (R2).

[0182] A base resin comprising, preferably composed of, a first ethylene polymer (B1) and a second ethylene polymer (B2) optionally together with a prepolymer fraction, preferably has a melt flow rate MFR2 (190°C, 2.16 kg) lower than that of the first ethylene polymer (B1) when determined according to ISO 1133.

[0183] To adjust the MFR2 of the base resin, preferably hydrogen is introduced into a second reactor (R2) to polymerize ethylene and a C3-C8α-olefin, preferably 1-butene or 1-hexene, more preferably 1-hexene, to obtain a second ethylene polymer (B2) with optionally a prepolymer fraction in the presence of a first ethylene polymer (B1). The hydrogen feed is preferably adjusted to the ethylene feed to satisfy a hydrogen-to-ethylene ratio of 0.5 to 10 mol / kmol, more preferably 1.0 to 9.0 mol / kmol, most preferably 2.0 to 8.0 mol / kmol in the second reactor (R2).

[0184] In particular, ethylene and C3-C8α-olefin are in the second reactor (R2) in the presence of the first ethylene polymer (B1) Polymerization is performed to obtain a second ethylene polymer (B2), and the first ethylene polymer (B1) and the second ethylene polymer (B2) together form a polyethylene composition (PC) satisfying inequality (IV):

[0185]

[0186] In inequality (IV),

[0187] H2 / C2(R2) is the molar ratio [mol / kmol] of hydrogen and ethylene in the second reactor (R1), and

[0188] MFR5(R2) is the melt flow rate MFR5 (5.0 kg, 190°C) of the polyethylene composition (C) when determined according to ISO 1133.

[0189] The comonomer supply amount is preferably adjusted to satisfy a comonomer-to-ethylene ratio of 20 to 100 mol / kmol, more preferably 30 to 80 mol / kmol, and most preferably 40 to 75 mol / kmol with respect to the ethylene supply amount.

[0190] In addition, the polymer fraction obtained in the second reactor (R2) corresponds to the second ethylene polymer (B2) described above.

[0191] The residence time and polymerization temperature in the second reactor (R2) are adjusted so that ethylene and C3-C8α-olefin, preferably 1-butene or 1-hexene, more preferably 1-hexene, are polymerized to obtain the second ethylene polymer (B2) in an amount generally 40 to 60 weight%, preferably 45 to 50 weight%, based on the total base resin.

[0192] In addition, the final polyethylene base resin exiting the gas-phase reactor preferably comprises a first ethylene polymer (B1) and a second ethylene polymer (B2) optionally together with a prepolymer fraction, and 940 kg / m³ when determined according to ISO 1183-1:2004. 3 Exceeding 960.0 kg / m³ 3Below, preferably 943 kg / m² 3 Exceeding 956 kg / m³ 3 Below, more preferably 945 kg / m² 3 Exceeding 950 kg / m³ 3 Below, most preferably 946 kg / m² 3 Exceeding 950 kg / m³ 3 It has the following density.

[0193] Where a prepolymer fraction is present, the base resin comprises a prepolymer fraction added to the amount of the first ethylene polymer (B1). The prepolymer fraction is present in the base resin in an amount of up to 7.5 weight%, more preferably up to 5 weight%, and most preferably up to 3 weight% based on the total base resin. The prepolymer fraction is preferably an ethylene homopolymer.

[0194] In addition, the base resin of the present method is as defined above for the polyethylene composition of the present invention.

[0195] Optionally, the method may further include a prepolymerization step prior to the first polymerization step. The purpose of the prepolymerization step is to polymerize a small amount of polymer using a catalyst at a low temperature and / or low monomer concentration. Prepolymerization can improve the performance of the catalyst in a slurry state and / or modify the properties of the final polymer.

[0196] Prepolymerization is carried out in a prepolymerization reactor. The prepolymerization reactor is preferably a prepolymerization slurry-phase reactor or a prepolymerization gas-phase reactor. More preferably, it is a prepolymerization slurry-phase reactor, and most preferably, a prepolymerization loop reactor.

[0197] Pre-polymerization is preferably carried out in an inert diluent, generally a hydrocarbon diluent such as methane, ethane, propane, n-butane, isobutene, pentane, hexane, heptane, octane, etc., or a mixture thereof. Preferably, the diluent is a low-boiling point hydrocarbon having 1 to 4 carbon atoms or a mixture of such hydrocarbons. The most preferred diluent is propane.

[0198] The temperature of the prepolymerization step is generally 0°C to 90°C, preferably 20°C to 80°C, more preferably 40°C to 70°C. The pressure is not important and is generally 1 bar to 150 bar, preferably 10 bar to 100 bar.

[0199] Generally, the amount of monomer is 0.1 g to 1000 g per 1 g of solid catalyst component and is polymerized during the prepolymerization step. As is known to those skilled in the art, catalyst particles recovered from a continuous prepolymerization reactor do not all contain the same amount of prepolymer. Instead, each particle has its own characteristic amount that depends on the residence time in the prepolymerization reactor. Because some particles remain in the reactor for a relatively long time and others for a relatively short time, the amount of prepolymer on different particles also differs, and some individual particles may contain an amount of prepolymer outside the above limits. However, the average amount of prepolymer present in the catalyst is generally within the limits specified above.

[0200] If desired, one or more alpha-olefin comonomers may be used in addition to the ethylene monomer during the prepolymerization step. Suitable comonomers are, for example, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and mixtures thereof. However, during the prepolymerization step, it is preferable to polymerize the ethylene homopolymer prepolymer fraction.

[0201] The molecular weight of the prepolymer can be controlled using hydrogen as is known in the art. Additionally, as disclosed in WO-A-96 / 19503 and WO-A-96 / 32420, an antistatic additive may be used to prevent particles from adhering to each other or to the reactor walls.

[0202] The prepolymer fraction obtained from the prepolymerization reactor is transferred to the first reactor (R1).

[0203] It is preferable to supply the catalyst system according to the present invention, that is, the catalyst and co-catalyst according to the present invention, to a first polymerization reactor.

[0204] However, if the solid catalyst component and the co-catalyst can be supplied separately, only a portion of the co-catalyst may be introduced into the first polymerization step, and the remainder into the subsequent polymerization step. Even in such cases, the necessary amount of co-catalyst must be introduced into the first polymerization step to obtain a sufficient polymerization reaction.

[0205] When using a prepolymerization step, it is desirable to introduce all catalyst components into the prepolymerization step. However, if the solid catalyst component and the co-catalyst can be supplied separately, only a portion of the co-catalyst may be introduced into the prepolymerization step, and the remainder into the subsequent polymerization step. Even in such cases, the necessary amount of co-catalyst must be introduced into the prepolymerization step to obtain a sufficient polymerization reaction.

[0206] The catalyst can be transferred to the polymerization zone by any method known in the art. Thus, the catalyst can be suspended in a diluent to maintain a uniform slurry state. In particular, it is preferable to use an oil with a viscosity of 20 to 1500 mPa·s as a diluent, as disclosed in WO-A-2006 / 063771. It is also possible to supply the paste produced by mixing the catalyst with a viscous mixture of grease and oil to the polymerization zone. Furthermore, after settling the catalyst, it is possible to introduce a portion of the catalyst mud thus obtained into the polymerization zone, for example, as disclosed in EP-A-428 054. The catalyst is described in more detail below.

[0207] The present invention includes embodiments comprising a prepolymerization step and embodiments not comprising a prepolymerization step. Both embodiments are equally preferred.

[0208] In an embodiment of the present invention comprising a prepolymerization step, the prepolymerization step is performed before the polymerization step. The purpose of the prepolymerization is to polymerize a small amount of polymer using a catalyst at a low temperature and / or low monomer concentration. Through prepolymerization, the performance of the catalyst in the slurry state can be improved and / or the properties of the final polymer can be modified. The prepolymerization step may be performed in a slurry or in the gas phase. Preferably, the prepolymerization is performed in a slurry, particularly in a loop reactor. Thus, the prepolymerization step may be performed in a loop reactor.

[0209] In addition, the residence time and polymerization temperature in the prepolymerization reactor are adjusted so that a prepolymer fraction of 1 to 5 weight%, preferably 2 to 4 weight%, and most preferably 2.5 to 3.5 weight% is polymerized based on the total base resin. The pressure is not critical and is generally 1 bar to 150 bar, preferably 10 bar to 100 bar.

[0210] The polyethylene composition of the present invention is preferably produced in a multi-stage process, which further comprises a compounding step in which a base resin, generally obtained as a base resin powder from a reactor, is extruded in an extruder and then pelletized into polymer pellets by a method known in the art to form the polyethylene composition of the present invention. Optionally, but less preferably, the base resin obtained from the reactor may be purged with nitrogen before extrusion.

[0211] Optionally, the polyethylene composition of the present invention can be produced by adding additives and / or other polymer components to the base resin during the compounding step. Additives commonly used in polyolefins include, for example, pigments, carbon black, stabilizers (e.g., antioxidants), antacids and / or UV blockers, antistatic agents, and utilization aids (e.g., processing aids). Additives are described in more detail below.

[0212] Preferably, the polyethylene composition comprises 8 weight percent or less, more preferably 1 to 4 weight percent, of carbon black based on the total polyethylene composition. More preferably, the amount of additives different from carbon black is 1 weight percent or less, more preferably 0.5 weight percent or less.

[0213] Additives may be added separately during the compounding step. However, it is preferable to pre-compound with one or more masterbatches and then add one or more masterbatches to the base resin during the compounding step.

[0214] The addition of additional polymer components is preferably limited to an amount of less than 3 weight percent, preferably less than 2 weight percent, based on the total polyethylene composition according to the present invention.

[0215] Preferably, the base resin of the present invention obtained from a gas-phase reactor is compounded in an extruder with additives and / or other polymers in a manner known in the art. The extruder may be, for example, any commonly used extruder. An example of an extruder for this compounding step may be one supplied by Japan Steel Works, Kobe Steel, or Farrel-Pomini, for example, JSW 460P or JSW CIM90P.

[0216] In one embodiment, the extrusion step is performed at a feed rate of 200 kg / h to 600 kg / h, more preferably 250 kg / h to 400 kg / h, at a pilot production scale. Preferably, the throughput in commercial production is generally 10 tons / h to 50 tons / h.

[0217] The following conditions apply to both pilot production and commercial production. The screw rotation speed of the extruder is preferably 300 rpm to 500 rpm, more preferably 350 rpm to 450 rpm.

[0218] Preferably, in the extrusion step, the SEI (specific energy input) of the extruder is 200 kWh / ton to 300 kWh / ton, more preferably 220 kWh / ton to 280 kWh / ton, and the SEI is calculated directly from the electrical input of the extruder, ignoring the inherently limited efficiency.

[0219] The melting temperature in the above extrusion step is preferably 220°C to 320°C, more preferably 250°C to 290°C.

[0220] Preferably, the zone temperatures of an extruder having four zones are set as follows. Zone 1 is preferably set to 80°C to 120°C. Zone 2 is preferably set to 180°C to 220°C. Zone 3 is preferably set to 230°C to 270°C. Zone 4 is preferably set to 160°C to 200°C. More preferably, the four zones are set as follows: Zone 1 to 90°C to 110°C; Zone 2 to 190°C to 210°C; Zone 3 to 240°C to 260°C; Zone 4 to 170°C to 190°C.

[0221] According to the present invention, the base resin of the polyethylene composition (PC) is obtained through a multi-stage polymerization method as described above in the presence of a catalyst system comprising a Ziegler-Natta catalyst (ZN).

[0222] A Ziegler-Natta catalyst (ZN) is obtained by a method comprising a reaction step of a support, wherein at least the surface of the support is

[0223] Magnesium halide compound having chemical formula (1):

[0224]

[0225] In chemical formula (1), R is C l -C 20 alkyl or C7-C 26 It is aralkyl, each identical or different X is a halogen, and n is an integer of 1 or 2,

[0226] Alkyl metal halide compound having chemical formula (2):

[0227]

[0228] In chemical formula (2), M is B or Al, and each is the same or different R 1 C l -C 10 Alkyl, and each identical or different X 1is a halogen, and when m1 is 1, n1 is 1 or 2, and when m1 is 2, n1 is an integer from 1 to 5,

[0229] A magnesium composition containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide - the magnesium composition has empirical formula (3) -:

[0230]

[0231] In the empirical formula (3), each identical or different R 2 is C1-C 20 alkyl, and each identical or different R 3 C1-C 20 C1-C containing alkyl or heteroatoms 20 It is alkyl, and n2 is 0.01 to 1.99, and

[0232] Titanium halide compound having chemical formula (4):

[0233]

[0234] In chemical formula (4), each identical or different R 4 is C1-C 20 Alkyl, and each identical or different X 2 is a halogen, n3 is an integer of 0 or 1 to 3, and Ti is tetravalent titanium.

[0235] Includes

[0236] Chemical formula (1) means that the inorganic support can be coated with MgCl2 or RoMgCl. Therefore, n is 1 or 2.

[0237] In the above, "magnesium composition" means a mixture or compound. Empirical formula (3) is an empirical formula based on the amount of magnesium Mg (defined as 1) and alkyl R 2 and alkoxy OR 3 It expresses the molar amount of, which is different from chemical formulas (1), (2), and (4) that disclose only the molecular composition of separate compounds.

[0238] Preferably, the method

[0239] a) The step of providing the support comprising a magnesium halide compound having the chemical formula (1),

[0240] b) A step of obtaining a first product by contacting the support comprising a magnesium halide compound having chemical formula (1) with the alkyl metal halide compound having chemical formula (2),

[0241] c) A step of obtaining a second product by contacting the first product with the magnesium composition having empirical formula (3) containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide, and

[0242] d) A step of contacting the second product with the titanium halide compound having the chemical formula (4).

[0243] Includes subsequent steps of.

[0244] The support used in the method is preferably in the form of particles, with a size of about 1 μm to about 1000 μm, preferably about 10 μm to about 100 μm. The support material must have a suitable particle size distribution, high porosity, and a large specific surface area. The support material is 100 to 500 m 2 Excellent results are achieved if it has a specific surface area of ​​ / g (support) and a pore volume of 1 to 3 ml / g (support).

[0245] The above catalyst components (2) to (4) react with a suitable catalyst support. If the catalyst components (2) to (4) are in the form of a low-viscosity solution, an excellent catalyst form and a correspondingly excellent polymer form can be achieved.

[0246] In a magnesium halide compound having the chemical formula (1), R is C1-C 20 alkyl or C7-C26 It is advantageous for it to be an aralkyl. However, it is preferable that the compound (1) be a magnesium dihalide, most preferably MgCl2. For example, the support may include solid MgCl2 as a powder alone or as a mixture with other inorganic powders.

[0247] According to another embodiment of the present invention, a support comprising a magnesium halide compound having the formula (1) also comprises an inorganic oxide. While various oxides are suitable, silicon, aluminum, titanium, chromium, and zirconium oxides or mixtures thereof are preferred. The most preferred inorganic oxides are silica, alumina, silica-alumina, magnesia, and mixtures thereof, and extremely preferably silica. The inorganic oxide may also be chemically pretreated, for example, by silylation or aluminum alkyl treatment.

[0248] It is recommended to dry the inorganic oxide before impregnating it with other catalyst components. Excellent results are achieved by heat-treating the oxide at 100°C to 900°C for a sufficient amount of time, thereby reducing the surface hydroxyl groups of silica to less than 2 mmol / g SiO2.

[0249] According to this aspect of the present invention, a support comprises particles having a core comprising the inorganic oxide and a shell comprising the magnesium halide compound having the formula (1). Then, a support comprising the magnesium halide compound having the formula (1) and the inorganic oxide can be conveniently prepared by treating the inorganic oxide particles with a magnesium halide solution and removing the solvent by evaporation.

[0250] When using a support containing both the magnesium halide compound (1) and another component, the amount of magnesium halide compound (1) is such that the support contains 1 to 20 weight%, preferably 2 to 6 weight% of magnesium.

[0251] Furthermore, the present invention comprises the step of reacting an alkyl metal halide compound of formula (2):

[0252]

[0253] In chemical formula (2), M is B or Al, and each is the same or different R 1 C l -C 10 Alkyl, and each identical or different X 1 is a halogen, m1 is 1 or 2, when m1 is 1, n1 is 1 or 2, and when m1 is 2, n1 is an integer from 1 to 5. In formula (2), M is preferably Al. Each identical or different R 1 is preferably a C1-C6 alkyl, and independently preferably the same or different halogen X 1 It is chlorine. n1 is preferably 1, and m1 is preferably an integer of 1 or 2. Most preferably, the alkyl metal halide compound having formula (2) is an alkyl aluminum dichloride, for example, ethyl aluminum dichloride (EADC).

[0254] Alkyl metal halide compounds are preferably deposited on a support material. Uniform deposition is preferably achieved when the viscosity of the halide or its solution is less than 10 mPa*s at the applied temperature. To achieve this low viscosity, the alkyl metal halide may be diluted with a non-polar hydrocarbon. However, optimal deposition is achieved when the total volume of the absorbed alkyl metal halide solution does not exceed the pore volume of the support. Using a 5% to 25% hydrocarbon solution of ethyl aluminum dichloride is an excellent choice. It is desirable to adjust the number of halide additions so that the pore volume is not exceeded at any addition, thereby ensuring that the chemical is uniformly distributed on the surface of the support material.

[0255] In the aforementioned preferred reaction step sequence a) to d), step b) can be advantageously performed by treating a support comprising a magnesium halide compound having formula (1) using an undiluted alkyl metal halide (2).

[0256] Alternatively, the support is an essentially nonpolar solvent, preferably a nonpolar hydrocarbon solvent, most preferably a C4-C 10 The support is contacted with a solution of an alkyl metal halide compound having the formula (2) in a hydrocarbon. The concentration of the alkyl metal halide compound having the formula (2) in the nonpolar solvent is generally 1 to 80 weight%, preferably 5 to 40 weight%, most preferably 10 to 30 weight%. Advantageously, the support is contacted with the solution of the alkyl metal halide compound (2) at a molar ratio of the alkyl metal halide compound (2) to a gram of the support of about 0.01 mmol / g to about 100 mmol / g, preferably about 0.5 mmol / g to about 2.0 mmol / g.

[0257] The amount of reactants can also be expressed as a molar ratio, and it is advantageous for the molar ratio of the alkyl metal halide compound (2) to the magnesium halide compound (1) to be about 0.01 mol / mol to about 100, preferably about 0.1 mol / mol to about 10, most preferably about 0.2 to about 3.0.

[0258] In step b), the contact temperature is, for example, 5°C to 80°C, preferably 10°C to 50°C, most preferably 20°C to 40°C. The contact time is 0.1 to 3 hours, preferably 0.5 to 1.5 hours.

[0259] In the method, in a magnesium composition having Empirical Formula (3) containing magnesium bound to hydrocarbyl and magnesium bound to hydrocarbyl oxide, each identical or different R 2 is preferably C2-C 10 alkyl, most preferably C2-C8 alkyl. Same or different R 3 It is preferably C3-C 20 Alkyl, more preferably branched C4-C 10 alkyl, most preferably 2-ethyl-1-hexyl or 2-propyl-1-pentyl.

[0260] A magnesium composition having empirical formula (3) containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide can also be defined by a method of manufacturing the same. According to one embodiment of the present invention, this is a contact product of dialkyl magnesium having formula (5):

[0261]

[0262] In chemical formula (5), each identical or different R 2 is as defined above and is an alcohol. Preferably, the dialkyl magnesium having the formula (5) is dibutyl magnesium, butyl ethyl magnesium or butyl octyl magnesium.

[0263] Accordingly, the magnesium composition contains magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide, and the magnesium composition having empirical formula (3) can be defined as a contact product of dialkyl magnesium and an alcohol having chemical formula (6):

[0264]

[0265] In chemical formula (6), each identical or different R 3 It is as defined above. Preferably, the alcohol having formula (6) is a 2-alkyl alkanol, most preferably 2-ethylhexanol or 2-propyl pentanol. It has been found that these branched alcohols yield better results than linear alcohols.

[0266] Preferably, the magnesium composition having Empirical Formula (3), containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide, is a contact product of dialkyl magnesium and alcohol, wherein the molar ratio of alcohol to dialkyl magnesium is 0.01 to 100 mol / mol, preferably 1.0 to 5.0 mol / mol, more preferably 1.7 to 2.0 mol / mol, and most preferably 1.8 to 1.98 mol / mol. The dialkyl magnesium and the alcohol are organic solvents, for example, C4-C 10 Contact is conveniently made by adding alcohol to the solution of the dialkyl magnesium in the hydrocarbon. Afterwards, the concentration of the solution is preferably 1 to 50 weight%, most preferably 10 to 30 weight%. The contact temperature between the dialkyl magnesium and the alcohol is preferably 10°C to 50°C, more preferably about 20°C to about 35°C.

[0267] In step c) of the aforementioned preferred sequence a) to d) of the claimed method, the contact product of the support and the alkyl metal halide compound (2), i.e., the first product, is brought into contact with a magnesium composition having empirical formula (3) containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide.

[0268] Preferably, the first product is contacted with the magnesium composition (3) under conditions where the molar ratio of magnesium / support g is 0.001 to 1000 mmol / g, preferably 0.01 to 100 mmol / g, most preferably 0.1 to 10 mmol / g (in the case of the first reaction product, support g refers to the support used as the starting material for the first reaction product).

[0269] When the volume of the magnesium composition (3) solution is about twice the pore volume of the support material, excellent deposition of the magnesium composition as a solution is achieved. This is achieved when the concentration of the composition in the hydrocarbon solvent is 5% to 60% relative to the hydrocarbon used. When depositing the magnesium composition onto the support material, the viscosity of the hydrocarbon solution thereof must be less than 10 mPa*s at the application temperature. The viscosity of the magnesium complex solution is, for example, R of the chemical formula (3). 4 It can be adjusted by the selection of the group, by the selection of the concentration of the hydrocarbon solution, by the selection of the ratio between magnesium alkyl and alcohol, or by the use of some viscosity reducing agent. A titanium compound can be added to the support with or without prior drying of the catalyst to remove volatile hydrocarbons.

[0270] If desired, residual hydrocarbons can be removed using slight reduced pressure, increased temperature, or nitrogen flash.

[0271] In the claimed method, the transition metal compound is a titanium halide compound having the chemical formula (4). R 4is preferably a C2-C8 alkyl, most preferably a C2-C6 alkyl. X 2 is preferably chlorine, and independently n3 is preferably 0. The titanium halide compound having the formula (4) is preferably titanium tetrachloride.

[0272] According to one embodiment of the present invention, in addition to the titanium compound having the formula (4), a titanium compound having the formula (7) is reacted:

[0273]

[0274] In chemical formula (7), each identical or different R 5 is C1-C 20 An alkyl group, preferably a C2-C8 alkyl group, most preferably a C2-C6 alkyl group, and each of the same or different X 3 The halogen is preferably chlorine, n4 is an integer from 1 to 4, and Ti is tetravalent titanium. The titanium compound (7) always has at least one alkoxy group, which helps to dissolve the titanium compound (4), which does not necessarily contain an alkoxide, in an organic solvent before contact. Naturally, the more alkoxide groups there are in the compound (4), the less the need for the compound (7) is. When using the compound (7), the preferred combination is a combination of titanium tetrachloride and titanium tetra C1-C6-alkoxide.

[0275] In step d) of the preferred sequence of steps a) to d), the second product is advantageously contacted with a titanium compound having compound (4) such that the molar ratio of the titanium compound / support g is 0.01 to 10 mmol / g, preferably 0.1 to 2 mmol / g. Preferably, the second reaction product is contacted with the titanium compound (4) such that the molar ratio of the titanium compound (4) to the magnesium compound (3) is 0.05 to 2 mol / mol, preferably 0.1 to 1.2 mol / mol, most preferably 0.2 to 0.7 mol / mol. The temperature is generally 10°C to 80°C, preferably 30°C to 60°C, most preferably about 40°C to about 50°C, and the contact time is generally 0.5 to 10 hours, preferably 2 to 8 hours, most preferably about 3.5 to about 6.5 hours.

[0276] In the polymerization, the alkyl metal halide compound of formula (2) may act as a co-catalyst, either wholly or partially, when used. However, it is preferable to add a co-catalyst having formula (9) to the polymerization mixture:

[0277]

[0278] In chemical formula (9), R6 is C1-C 20 Alkyl, preferably C1-C 10 alkyl, most preferably a C2-C6 alkyl such as ethyl, X is a halogen, preferably chlorine, and n is 1 to 3, more preferably 2 or 3, most preferably 3. The co-catalyst of formula (9) is optional depending on whether the alkyl metal halide compound (2) acts as a co-catalyst.

[0279] According to step b) of the present method, the base resin may be combined with an additive (AD) and / or a filler.

[0280] Common additives include acid removers, antioxidants, colorants, light stabilizers, plasticizers, lubricants, anti-scratch agents, dispersants, processing aids, lubricants, pigments, and fillers. For fillers, refer to the definition provided above.

[0281] These additives are commercially available, for example, "Plastic Additives Handbook", 6 th It is listed in the 2009 edition of Hans Zweifel (pages 1141 to 1190).

[0282] In addition, according to the present invention, the term "additive (AD)" includes a carrier material, in particular a polymeric carrier material.

[0283] Polymeric carrier material (i.e., masterbatch carrier polymer)

[0284] The polyethylene composition (PC) of the present invention preferably does not contain an additional polymer different from the first ethylene polymer (B1) and the second ethylene polymer (B2) in an amount greater than 15 weight%, preferably greater than 10 weight%, and more preferably greater than 9 weight%. If an additional polymer is present, such polymer is generally a polymeric carrier material for an additive (AD). The carrier material for the additive (AD) is calculated based on the amount of each additive, not the amount of the polymeric compound specified in the present invention.

[0285] The polymeric carrier material of the additive (AD) is a carrier polymer that ensures a uniform distribution in the polyethylene composition (PC) of the present invention. The polymeric carrier material is not limited to a specific polymer. The polymeric carrier material may be an ethylene homopolymer, an ethylene copolymer obtained from ethylene and an α-olefin comonomer such as a C3 to C8 α-olefin comonomer, a propylene homopolymer and / or a propylene copolymer obtained from propylene and an α-olefin comonomer such as an ethylene and / or a C4 to C8 α-olefin comonomer.

[0286] According to step c) of the method of the present invention, a polyethylene composition (PC) is extruded through a suitable die to obtain a pipe.

[0287] Polymer pipes are generally manufactured by extrusion or small-batch injection molding. A typical plant for polymer pipe extrusion includes an extruder, a die head, a straightening device, cooling equipment, a pulling device, and devices for cutting and / or coiling the pipe.

[0288] The manufacture of polyethylene materials used in pressure pipes is discussed in the paper by Scheirs et al. (Scheirs, Bohm, Boot and Leevers: PE100 Resins for Pipe Applications, TRIP Vol. 4, No. 12 (1996), pp. 408-415). The authors discuss the production technology and characteristics of PE100 pipe materials. They state that appropriate comonomer and molecular weight distributions are important for optimizing slow crack growth and rapid crack propagation. Points out.

[0289] The present invention will now be explained in more detail through the examples provided below.

[0290] Examples

[0291] 1. measurement method

[0292] Unless otherwise defined, the definitions and determination methods of the following terms apply to the general description of the invention above as well as to the embodiments below.

[0293] MFR 2 (190℃) It was measured according to ISO 1133 (190℃, 2.16 kg load).

[0294] MFR 5 (190℃) It was measured according to ISO 1133 (190℃, 5.0 kg load).

[0295] MFR 21 (190℃) It was measured according to ISO 1133 (190℃, 21.6 kg load).

[0296] polymer density Compression molding manufactured according to EN ISO 1872-2 (February 2007) Measured on specimens according to ISO 1183-1:2004 Method A, kg / m² 3 It is given as.

[0297] polymer comonomer The amount was determined by quantitative nuclear magnetic resonance (NMR) spectroscopy. Quantitative 13 C{ 1 H}NMR spectrum in the molten state 1 H and 13 For C, the results were recorded using a Bruker Advance III 500 NMR spectrometer operating at 500.13 MHz and 125.76 MHz, respectively. All spectra are 13 Recording was performed using nitrogen gas for all pneumatics at 150°C with a 7 mm Magic Angle Spinning (MAS) probe head optimized for C. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz. This setup was primarily selected for the high sensitivity required for rapid identification and accurate quantification {[1], [2], [6]}. Standard single-pulse excitation was used utilizing transient NOE with a short recycling delay of 3 seconds {[1], [3]}, and RSHEPT decoupling was also used {[4], [5]}. A total of 1024 (1k) transients per spectrum were acquired. This setup was selected due to its high sensitivity to low comonomer content.

[0298] Quantitative 13 C{ 1H} NMR spectra were processed and integrated using a custom spectral analysis automation program, and quantitative characteristics were determined. All chemical shifts are internally referenced to the bulk methylene signal (δ+) at 30.00 ppm{[9]}.

[0299] A characteristic signal corresponding to the incorporation of 1-hexene was observed{[9]}, and all content was calculated based on all other monomers present in the polymer.

[0300]

[0301] Since no other comonomer sequences or other signals indicating continuous comonomer incorporation were observed, the total observed 1-hexene comonomer content was calculated based solely on the amount of the isolated 1-hexene sequence:

[0302]

[0303] Characteristic signals originating from saturated terminals were observed. The content of these saturated terminals was quantified using the signal integral averages at 22.84 ppm and 32.23 ppm assigned to the 2s and 3s sites, respectively:

[0304]

[0305] The relative content of ethylene was quantified using the integration of the bulk methylene(δ+) signal at 30.00 ppm:

[0306]

[0307] The total ethylene comonomer content was calculated based on the bulk methylene signal and considering other observed comonomer sequences or ethylene units present at the terminals:

[0308]

[0309] Subsequently, the total mole fraction of 1-hexene in the polymer was calculated as follows:

[0310]

[0311] The total comonomer incorporation mol% of 1-hexene was calculated from the mole fraction using the general method:

[0312]

[0313] The total weight percentage of comonomer incorporation of 1-hexene was calculated from the mole fraction using a standard method:

[0314]

[0315]

[0316]

[0317] Amount of hexane solution (C6) [weight%] It was determined through Soxhlet extraction.

[0318] Approximately 1 g of the powdered test sample was carefully dried and accurately weighed. The powdered test sample was extracted in a Soxhlet apparatus with 150 ml of n-hexane (PA grade) for 24 hours. A standard 603 cellulose extraction thimble was used as the thimble. To prevent the polymer powder from escaping the extraction thimble, the top of the thimble was cut in half and closed. After extraction, the weight of the glass extractor containing the polymer was weighed once a constant weight was reached. The mass of the residue of the test sample in the glass extractor was determined using the following formula:

[0319]

[0320] In the equation,

[0321] m1 = original sample weight, and

[0322] m2 = weight of the glass extractor containing the polymer after extraction, and

[0323] mt = weight of the glass extractor.

[0324] Pressure testing in notched pipes (NPT); resistance to slow crack propagation:

[0325] Slow crack propagation resistance was determined according to ISO 13479-2009 as the time the pipe could withstand at specific temperatures and pressures before failure. Pressure tests were performed on notched SDR11 pipes with an outer diameter of 110 mm. A pressure of 4.6 MPa and a temperature of 80°C were used. Notching was performed using a climb milling cutter with a V-shaped cutter having a 60° inclusion angle compliant with ISO 6108, at a cutting speed of 0.010 ± 0.002 (mm / rev) / tooth. The cutter used had 24 teeth, and the cutter rotation speed was 680 rpm. The residual ligament was 0.82 to 0.78 times the minimum wall thickness. The notch depth was calculated using the following formula, where h is the notch depth in mm. Four notches were placed at equal intervals around the circumference of the pipe. The length of the notches was 110 ± 1 mm.

[0326]

[0327] b s is the width of the notched machined surface in mm, and

[0328] d em is the measured average pipe outer diameter in mm.

[0329] Hydrostatic Testing (HPT) on Un-Notched Pipes; Internal Pressure Resistance:

[0330] Internal pressure resistance was determined by pressure testing in both underwater and out-of-water environments on an unnotched 32 mm SDR 11 pipe with a length of 450 mm in accordance with ISO 1167-1:2006. Type A end caps were used. The time to failure was determined in hours. . Hoop stresses of 5.7 MPa and 5.9 MPa were applied at a temperature of 80℃, and hoop stresses of 12.2 MPa and 12.6 MPa were applied at 20℃.

[0331] of the compound Strain hardening rate coefficientIt was obtained from a tensile stress-strain curve exceeding natural elongation and shows an increasing slope of the stress-strain trend at very high strain (strain hardening region). This was measured using a 300 μm thick specimen preconditioned (120°C / hour) at 80°C and a speed of 20 mm / min according to ISO 18488.

[0332] 2. Examples

[0333] Catalyst manufacturing

[0334] 7.9 g (60.8 mmol) of 2-ethyl-1-hexanol was slowly added to 27.8 g (33.2 mmol) of 19.9% ​​butyl-octyl-magnesium. The reaction temperature was maintained below 35°C. This complex was used to prepare the catalyst below. The 2-ethyl-1-hexanol / butyl-octyl-magnesium ratio was 1.83:2.

[0335] 3.7 g of 20% EADC (1.0 mmol per 1 g of carrier) was added to 5.9 g of Sylopol 5510 silica / MgCl2 carrier, and the mixture was stirred at 30°C for 1 hour. 5.7 g of the complex prepared as described above (0.9 mmol per 1 g of carrier) was added, and the mixture was stirred at 35°C to 45°C for 4 hours. 40.6 g of TiCl (0.55 mmol per 1 g of carrier) was added, and the mixture was stirred at 45°C for 5 hours. The catalyst was dried at 45°C to 80°C for 3 hours.

[0336] Catalyst composition: Al 1.8%, Mg 3.9%, Ti 2.1%, Cl 18.6%.

[0337] Preparation of the polyethylene composition (C) for pipes according to the present invention

[0338] The volume is 50 dm 3An in-loop reactor was operated at 60°C and a pressure of 65 bar. To produce the prepolymer fraction, 50 kg / h of propane diluent, 2 kg / h of ethylene, and 5 g / h of hydrogen were introduced into the reactor. Additionally, the aforementioned catalyst was introduced into the reactor along with a triethylaluminum co-catalyst to achieve a molar ratio of aluminum to titanium of 15 mol / mol. No comonomer was introduced into the reactor. The conditions within the reactor were as presented in Table 1.

[0339] The polymer slurry is discharged from the loop reactor, and the volume is 500 dm³ 3 It was transferred to an in-loop reactor. This second-loop reactor was operated at 95°C and a pressure of 65 bar. Propane diluent, ethylene, and hydrogen were introduced into the reactor, and the molar ratio of hydrogen to ethylene is presented in Tables 1 and 4. The polymerization rate and reactor conditions are presented in Tables 1 and 4.

[0340] The polymer slurry was discharged from the second loop reactor and transferred to a flash vessel to substantially remove hydrocarbons from the polymer. Subsequently, the polymer was introduced into a gas phase reactor operating at a temperature of 85°C and a pressure of 20 bar. Additionally, ethylene, 1-hexene, nitrogen as an inert gas, and hydrogen were introduced into the reactor, and the molar ratio of 1-hexene to ethylene, the molar ratio of hydrogen to ethylene, as well as the production splitting rate, melt flow rate, and the density of the polymer discharged from the gas phase reactor are listed in Table 1. The polymerization rate and conditions are presented in Table 1.

[0341] The generated polymer was purged with nitrogen (approx. 50 kg / h) for 1 hour, stabilized with 2200 ppm of Irganox B225 and 1500 ppm of Ca-stearate, and then extruded into pellets in a reverse twin-screw extruder CIM90P (manufactured by Japan Steel Works) together with 5.75 wt% of carbon black masterbatch (containing 40 wt% carbon black and 60 wt% HDPE). The temperature profiles for each zone were 90 / 120 / 190 / 250℃.

[0342] Preparation of polyethylene composition for comparative pipes

[0343] A polyethylene composition for comparative pipes was polymerized using the same procedure as the composition of the present invention, except that the commercially available Lynx 200 catalyst from WR Grace (USA) was used. The catalyst and co-catalyst components were applied such that the ratio of aluminum to titanium was 15 mol / mol. The reactor configuration is presented in Table 1. The resulting base resin was processed and compounded in the same manner as the composition of the present invention.

[0344] CE3 to CE5 are also bimodal C2 / C2C6 copolymers obtained from various commercial sources and have properties similar to CE1 and CE2.

[0345] Pipe manufacturing

[0346] The compounded composition was extruded into an SDR 11 pipe for pressure resistance testing and notch pipe testing.

[0347]

[0348]

[0349]

[0350] As can be seen in Table 3, for Comparative Examples CE4 and CE5, the HPT breakdown time at 5.9 MPa and 80°C was less than 30 hours. The corresponding values ​​of the embodiments of the present invention were significantly higher.

[0351] FIG. 1 plots the log(HPT) values ​​at 5.9 MPa and 80°C as a function of the strain hardening coefficient, and FIG. 2 plots the log(HPT) values ​​at 5.7 MPa and 80°C as a function of the strain hardening coefficient. An embodiment of the present invention satisfies the following inequality:

[0352]

[0353] and

[0354]

[0355] Likewise, the failure time in hydrostatic tests for IE3, IE4, and IE8 at 12.4 MPa and 20°C and 5.7 MPa and 80°C was longer than the corresponding failure time of CE1, CE2, and CE3 at similar strain hardening rate values.

Claims

Claim 1 i) based on the total weight of the base resin (B) 30.0 to 70.0 weight% of a first ethylene polymer (B1) which is an ethylene homopolymer or a copolymer of ethylene and C3-C8α-olefin, and ii) A base resin (B) comprising 30.0 to 70.0 weight% of a second ethylene polymer (B2) which is a copolymer of ethylene and C3-C8α-olefin and has a lower density than the first copolymer (B1). Claim 2 In claim 1, the base resin (B) having an amount of hexane solution of 1.30 weight% or less based on the total weight of the base resin (B) when determined according to the method given in the measurement method. Claim 3 In claim 1 or 2, the first ethylene polymer (B1) is 960 to 980 kg / m³ when determined according to ISO 1183-1:2004. 3 A base resin (B) having a density in the range and / or a molecular weight distribution (Mw / Mn) of 29.4 or less. Claim 4 A base resin (B), wherein, in any one of claims 1 to 3, the first ethylene polymer (B1) is an ethylene homopolymer and the second copolymer (B2) is a copolymer of ethylene and 1-hexene. Claim 5 In any one of claims 1 to 4, the base resin (B) is obtained by a method comprising the step of reacting a support in the presence of a Ziegler-Natta catalyst (ZN), and at least the surface of the support is a magnesium halide compound having the chemical formula (1): In chemical formula (1), R is C l -C 20 alkyl or C7-C 26 An alkyl metal halide compound having the formula (2), wherein each identical or different X is a halogen and n is an integer of 1 or 2: In chemical formula (2), M is B or Al, and each is the same or different R 1 C l -C 10 Alkyl, and each identical or different X 1 is a halogen, and when m1 is 1, n1 is 1 or 2, and when m1 is 2, n1 is an integer from 1 to 5, a magnesium composition containing magnesium bonded to hydrocarbyl and magnesium bonded to hydrocarbyl oxide - the magnesium composition has empirical formula (3) -: In the empirical formula (3), each identical or different R 2 is C1-C 20 alkyl, and each identical or different R 3 C1-C 20 C1-C containing alkyl or heteroatoms 20 A titanium halide compound having the chemical formula (4), wherein n2 is 0.01 to 1.99, and is alkyl: In chemical formula (4), each identical or different R 4 is C1-C 20 Alkyl, and each identical or different X 2 A base resin (B) comprising , which is a halogen, n3 is an integer of 0 or 1 to 3, and Ti is tetravalent titanium. Claim 6 a) Based on the total weight of the polyethylene composition (PC), at least 90 weight% of the base resin (B) according to any one of claims 1 to 5, b) Pigment (P), and c) A polyethylene composition (PC) that optionally includes an additive (AD). Claim 7 In Paragraph 6, i) 957 to 965 kg / m³ when determined according to ISO 1183-1:2004 3 Density of the range, and ii) Flow velocity ratio FRR in the range of 27 to 36 21 / 5 = MFR 21 / MFR5- MFR5 is the melt flow rate determined according to ISO 1133 at a temperature of 190°C and a load of 5.0 kg, and MFR 21 A polyethylene composition (PC) having a melt flow rate determined according to ISO 1133 at a temperature of 190°C and a load of 21.6 kg. Claim 8 In claim 6 or 7, the pigment (P) is a polyethylene composition (PC) selected from the group consisting of carbon black, molybdenum orange and cadmium orange. Claim 9 In any one of paragraphs 6 to 8, a melt flow rate MFR5 (5.0 kg, 190°C) of less than 2.0 g / 10 min as determined according to ISO 1133 and / or a melt flow rate MFR in the range of 0.5 to 12.0 g / 10 min as determined according to ISO 1133 21 Polyethylene composition (PC) having (21.6 kg, 190℃). Claim 10 A polyethylene composition (PC) having a strain hardening modulus in the range of 50.0 to 85.0 MPa in any one of claims 6 to 9. Claim 11 A pipe comprising at least 90 weight percent of a polyethylene composition (PC) according to any one of claims 6 to 10. Claim 12 In Clause 11, satisfying inequality (II) and / or inequality (III): In inequality (II) and / or inequality (III), HPT 5.9 is the hydrostatic pressure test value [h] of the pipe determined at a pressure of 5.9 MPa and a temperature of 80℃, and HPT 5.7 A pipe, wherein [h] is the hydrostatic pressure test value of the pipe determined at a pressure of 5.7 MPa and a temperature of 80°C, and SH is the strain hardening coefficient of the polyethylene composition (PC) [MPa]. Claim 13 In paragraph 11 or 12, a pipe that is a fluid pipe, preferably an oil or water pipe. Claim 14 A pipe that is a pressure pipe in any one of paragraphs 11 to 13. Claim 15 a) Step of manufacturing a base resin (B) in a sequential process comprising at least two reactors: i) A step of polymerizing ethylene and optionally C3-C8α-olefin in a first reactor (R1) to obtain a first ethylene polymer (B1) satisfying inequality (IV): In inequality (IV), H2 / C2(R1) is the molar ratio [mol / kmol] of hydrogen and ethylene in the first reactor (R1), and MFR2(R1) is the melt flow rate MFR2 (2.16 kg, 190°C) of the first ethylene polymer (B1) obtained in the first reactor (R1) when determined according to ISO 1133, ii) A step of transferring the first ethylene polymer (B1) obtained in the first reactor (R1) to the second reactor (R2), iii) A step of polymerizing ethylene and C3-C8α-olefin in the presence of a first ethylene polymer (B1) in a second reactor (R2) to obtain a second ethylene polymer (B2) - the first ethylene polymer (B1) and the second ethylene polymer (B2) together form a base resin (B) satisfying inequality (V) -: In the inequality (V), H2 / C2(R2) is the molar ratio of hydrogen and ethylene in the second reactor (R2) [mol / kmol], and MFR5(R2) is the melt flow rate MFR5 (5.0 kg, 190℃) of the base resin (B) when determined according to ISO 1133, b) A step of obtaining a polyethylene composition (PC) by combining a base resin with a pigment (P) and optionally an additive (AD), and c) A method for manufacturing a pipe according to any one of claims 11 to 14, comprising the step of extruding a polyethylene composition (PC) through a suitable die to obtain a pipe.

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