Propylene-based terpolymer compositions for pipes

Abstract

The present invention relates to a pipe comprising a polypropylene composition (P), the polypropylene composition (P) comprising a terpolymer composition (A), a nucleating agent (B) and optionally a composition comprising a pigment (C), wherein the terpolymer composition (A) comprises at least one terpolymer prepared from propylene, ethylene and 1-hexene, wherein the nucleating agent (B) is a nucleating agent comprising a metal salt of hexahydrophthalic acid represented by formula (I), wherein M1 and M2 are the same or different and can be combined into one cation and are at least one metal cation selected from calcium, strontium, lithium and monovalent aluminum; and wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 are the same or different and are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogen, and phenyl, wherein the polypropylene composition (P) has a melt flow rate of 0.10 to 0.70 dg / min measured by ISO 1133-1:2011 at 230°C and 2.16 kg.

Description

[0001] The present invention relates to a polypropylene composition comprising a terpolymer composition, an article comprising the polypropylene composition, preferably a pipe, a method for preparing such a composition, and the use of the polypropylene composition.

[0002] Polymer-based polypropylenes have a variety of properties that make them suitable for a variety of applications, such as pipes like cold and hot water pressure pipes. For cold and hot water pressure pipes, it is particularly important that such pipes exhibit no brittle failure over a long period of time (especially at high temperatures), combined with good impact resistance. No brittle failure over a long period of time is required to ensure the lifespan of the pipe during use. Good impact resistance is very important during the operation (installation, transportation, etc.) of the pipe.

[0003] Attempts have been made to achieve advantageous properties by using different types of comonomers and changing process conditions.

[0004] It is known in the art to use propylene / ethylene / 1-hexene terpolymers to produce pipes. For example, WO2006 / 002778 relates to a pipe system comprising a terpolymer of propylene / ethylene and an alpha-olefin, wherein the ethylene content is from 0 to 9 mol%, preferably from 1 to 7 mol% and the 1-hexene content is from 0.2 to 5 wt%. WO2013 / 083575 discloses a terpolymer containing propylene, ethylene and 1-hexene, wherein: (i) the content of 1-hexene-derived units is from 1 wt% to 3.2 wt%, (ii) the content of ethylene-derived units is higher than 1.4 wt% and C2 content < C6 content - 0.2, further defined by MFR and melting temperature.

[0005] There is still a need in the art for pipes comprising propylene-based terpolymer compositions having high pipe impact resistance and high pipe hydrostatic pressure resistance.

[0006] Accordingly, an object of the present invention is to provide a propylene / ethylene / 1-hexene terpolymer composition, from which pipes having high pipe impact resistance and high pipe hydrostatic pressure resistance are made.

[0007] Accordingly, the present invention provides a polypropylene composition (P) comprising a terpolymer composition (A), a nucleating agent (B), and optionally a composition comprising a pigment (C),

[0008] wherein the terpolymer composition (A) comprises at least one terpolymer prepared from propylene, ethylene and 1-hexene,

[0009] wherein the nucleating agent (B) is a nucleating agent comprising a metal salt of hexahydrophthalic acid represented by formula (I),

[0010]

[0011] wherein M1 and M2 are the same or different and can be combined into a cation and are selected from at least one metal cation of calcium, strontium, lithium and monovalent aluminum; and wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 are the same or different and are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogen, and phenyl,

[0012] Wherein the polypropylene composition (P) has a melt flow rate of 0.10 to 0.70 dg / min, measured according to ISO 1133-1:2011 at 230°C and 2.16 kg.

[0013] It has been unexpectedly found that the polypropylene composition of the present invention can be used to prepare pipes that exhibit high tube impact resistance and long-term non-brittle failure. In addition, pipes prepared from the terpolymers of the present invention can be extruded at higher speeds, which means that pipes can be produced at higher throughputs and / or using less energy, which is advantageous from an environmental as well as a cost point of view.

[0014] The term "pipe" as used herein also includes pipe fittings, valves and all components typically required for, for example, hot water pipe systems. Also included within this definition are single-layer pipes and multi-layer pipes, where, for example, the pipe may include one or more metal layers and may include one or more adhesive layers.

[0015] Polypropylene composition (P)

[0016] Preferably, in the polypropylene composition (P) the weight ratio of the total amount of ethylene derived units to the total amount of 1-hexene derived units in the polypropylene composition (P) is at least 0.70, preferably at least 0.80, more preferably at least 0.90 and / or at most 3.0, preferably at most 2.5. This leads to a good balance of pipe shock and pipe pressure.

[0017] Preferably, the present invention is directed to a polypropylene composition (P) according to any of the claims, wherein the sum of the amounts of the terpolymer composition (A), the nucleating agent (B) and the composition comprising the pigment (C) is at least 95 wt.-%, based on the polypropylene composition (P).

[0018] More preferably the sum of the amounts of terpolymer composition (A), nucleating agent (B) and the composition comprising pigment (C) is at least 96 wt.-%, such as at least 97 wt.-%, like at least 98 wt.-%, based on the polypropylene composition (P).

[0019] The polypropylene composition (P) may further comprise an additive (D). Preferably, the polypropylene composition (P) does not comprise polymers other than the terpolymer. Preferably, the sum of the amounts of the terpolymer composition (A), the nucleating agent (B) and the composition comprising the pigment (C) and the additive (D) is 100 wt.-%, based on the polypropylene composition.

[0020] Examples of additives (D) that may be present in the polypropylene composition of the present invention are additives suitable for use in pipes, and include, but are not limited to, stabilizers, antioxidants, impact modifiers, flame retardants, acid scavengers, biocides and the like. Such additives are well known in the art. The skilled person will select the type and amount of additives so that they do not adversely affect the intended properties of the composition.

[0021] For example, the amount of the additive D) in the composition is selected from 0 to 5 wt.-% based on the total weight of the polypropylene composition (the polypropylene composition (P) comprises 95 to 100 wt.-% of the sum of the amounts of the terpolymer composition (A), the nucleating agent (B) and the composition comprising the pigment (C)), such as the amount of the additive is 1.0 to 3.0 wt.-% based on the total weight of the polypropylene composition (P) (the polypropylene composition (P) comprises 97.0 to 99.0 wt.-% of the sum of the amounts of the terpolymer composition (A), the nucleating agent (B) and the composition comprising the pigment (C)).

[0022] The polypropylene composition (P) has a melt flow rate (MFR) (ISO 1133-1:2011, 230°C, 2.16 kg) of 0.10 to 0.70 dg / min, preferably 0.10 to 0.50 dg / min, more preferably 0.10 to 0.30 dg / min.

[0023] The total amount of ethylene derived units in the polypropylene composition (P) is preferably at least 1.5 wt.-%, such as at least 1.6 wt.-%, such as at least 1.7 wt.-% and / or such as at most 5.0 wt.-%, such as at most 4.0 wt.-%, such as at most 3.5 wt.-%, such as at most 3.0 wt.-%, such as at most 2.8 wt.-%.

[0024] Preferably, the total amount of ethylene derived units in the polypropylene composition (P) is 1.5 to 5.0 wt.%, such as 1.6 to 4.0 wt.%, such as 1.6 to 3.5 wt.%, such as 1.7 to 3.5 wt.%, such as 1.7 to 3.0 wt.%, such as 1.8 to 2.8 wt.%.

[0025] The total amount of 1-hexene derived units in the polypropylene composition (P) is at least 1.5 wt.-%. This ensures a high resistance to brittle failure and a high hydraulic pressure resistance. For example, the total amount of 1-hexene derived units in the polypropylene composition (P) is at least 1.6 wt.-%, such as at least 1.7 wt.-%, such as at least 1.8 wt.-% and / or at most 4.0 wt.-%, such as at most 3.5 wt.-%, such as at most 3.0 wt.-%.

[0026] Preferably, the total amount of 1-hexene derived units in the polypropylene composition (P) is 1.5 to 4.0 wt.%, such as 1.6 to 4.0 wt.%, such as 1.7 to 4.0 wt.%, such as 1.7 to 3.5 wt.%, such as 1.8 to 3.0 wt.%.

[0027] Preferably, for good pipe pressure resistance the content (in wt%) of ethylene derived units in the polypropylene composition (P) is similar to or greater than the content (in wt%) of 1-hexene derived units in the polypropylene composition.

[0028] Preferably, in the polypropylene composition (P),

[0029] TC2 ≥ TC6-0.20,

[0030] wherein TC2 represents the total amount (in wt%) of ethylene derived units in the polypropylene composition, and wherein TC6 represents the total amount (in wt%) of 1-hexene derived units in the polypropylene composition. More preferably, in the polypropylene composition (P),

[0031] TC2≥TC6-0.10

[0032] wherein TC2 represents the total amount of ethylene derived units in the polypropylene composition (in wt%), and wherein TC6 represents the total amount of 1-hexene derived units in the polypropylene composition (in wt%). Most preferably, for optimal pipe pressure resistance, in the polypropylene composition (P),

[0033] TC2>TC6

[0034] wherein TC2 represents the total amount (in wt%) of ethylene derived units in the polypropylene composition, and wherein TC6 represents the total amount (in wt%) of 1-hexene derived units in the polypropylene composition.

[0035] The total amount of ethylene derived units and the total amount of 1-hexene derived units in the polypropylene composition or in the terpolymer composition is determined by the term "C2, C6 comonomer content" as used herein. 13 C-NMR" section.

[0036] Preferably, the polypropylene composition (P) has a carbonyl group of at least 7.0, more preferably at least 7.5, more preferably at least 8.0. <gp> / Y, where <gp>represents the strain hardening modulus and Y represents the yield stress, and where <gp> / Y is determined as follows:

[0037] a) providing a test specimen of the composition by compression molding the composition into a sheet having a thickness of 0.3 mm ± 0.025 mm according to ISO 1873-2 and punching the sheet into a test specimen having the test specimen geometry described in ISO / DIS 18488, wherein after compression molding and before punching, the sheet is annealed at a temperature of 100° C. for 1 hour and cooled to room temperature,

[0038] b) Elongate the sample at a constant transverse speed of 20 mm / min at 100°C,

[0039] c) measuring the load on the specimen during elongation to obtain a stress-strain curve and measure the yield stress Y,

[0040] d) calculating the true stress-true strain curve from the stress-strain curve obtained in step c) according to the method described in ISO / DIS18488, and calculating the tensile strain hardening modulus from the true stress-strain curve <gp>,and

[0041] e) Calculation of tensile strain hardening modulus <gp>Divide the quotient by the yield stress Y.

[0042] Preferably, the lowest temperature at which at most 1 tube out of 10 tubes made of the composition according to the present invention fails as determined by DIN 8078 (2008) is 0.0°C, preferably -1.0°C, more preferably -2.0°C, even more preferably -3.0°C, most preferably -4.0°C.

[0043] Preferably, the pipe made from the polypropylene composition (P) has a run time without damage of at least 5000 h measured according to ISO 1167-1 at a temperature of 95 °C and a hoop stress of 4.2 MPa calculated according to ISO 3213. Preferably, the pipe made from the polypropylene composition (P) has a run time without damage of at least 5000 h measured according to ISO 1167-1 at a temperature of 20 °C and a hoop stress of 13.0 MPa calculated according to ISO 3213.

[0044] The polypropylene composition (P) preferably has a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of 5.0 to 25.0, such as 6.0 to 22.0, such as 7.0 to 20.0, such as 8.0 to 20.0, such as 8.0 to 16.0, such as 8.0 to 14.0, wherein Mw and Mn are measured according to ASTM D6474-12.

[0045] Preferably, the polypropylene composition (P) has a polydispersity index (PI) of 4.0 to 15.0, such as 5.0 to 15.0, preferably 6.5 to 12.0, wherein PI is a polydispersity index of 10 5 Pa is determined by dividing the crossover modulus Gc, where Gc occurs when the storage modulus (G') and the loss modulus (G") are equal, and where G' and G" are measured using dynamic force spectroscopy.

[0046] For example, the weight average molecular weight of the polypropylene composition (P) measured according to ASTM D6474-12 is 500 to 1500 kg / mol, more preferably 650 to 1100 kg / mol. For example, the number average molecular weight of the polypropylene composition (P) measured according to ASTM D6474-12 is 70 to 110 kg / mol, more preferably 80 to 105 kg / mol.

[0047] Terpolymer composition (A)

[0048] Preferably, the terpolymer composition (A) has at most 10 wt.-% XS based on the terpolymer, more preferably the polypropylene composition (P) has at most 10 wt.-% XS based on the polypropylene composition (P). XS stands for the amount of xylene solubles, measured using the conditions as described in the experimental section of this application.

[0049] Preferably, the amount of the terpolymer prepared from propylene, ethylene and 1-hexene in the terpolymer composition (A) is at least 95 wt.-%, more preferably at least 97 wt.-%, even more preferably at least 99 wt.-%, most preferably 100 wt.-%, based on the terpolymer composition (A), i.e. most preferably, the terpolymer composition (A) consists only of one or more terpolymers prepared from propylene, ethylene and 1-hexene.

[0050] The terpolymer in the terpolymer composition (A) may be unimodal or multimodal, such as bimodal, as detailed herein.

[0051] Nucleating agent (B)

[0052] In the composition according to the present invention, the nucleating agent comprises a metal salt of hexahydrophthalic acid represented by formula (I),

[0053]

[0054] wherein M1 and M2 are the same or different and can be combined into a cation and are selected from at least one metal cation of calcium, strontium, lithium and monovalent aluminum; and wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 are the same or different and are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogen, and phenyl.

[0055] The use of such a nucleating agent unexpectedly results in higher tube impact resistance and improved tube static pressure resistance.

[0056] In a preferred embodiment, M1 and M2 are combined to form a calcium ion, and preferably the compound of formula (I) is a cis-calcium hexahydrophthalate compound of formula (II):

[0057]

[0058] Preferably, the amount of compound (I) or (II) in the nucleating agent (B) is at least 30% by weight of the nucleating agent. An example of a suitable nucleating agent comprising a compound of formula (II) is commercially available from Milliken HPN-20E TM Nucleating agent. This nucleating agent comprises a cis-hexahydrophthalic acid calcium compound of formula (II) and a stearate-containing compound as an acid scavenger, such as zinc stearate, in a weight ratio of 2:1.

[0059] Preferably the nucleating agent (B) is present in an amount of 10 to 5000 ppm (0.001 to 0.50 wt. %), like in an amount of 100 to 2500 ppm, based on the polypropylene composition (P).

[0060] Pigment (C)

[0061] The pigment (C) can be added as such (the composition comprising the pigment (C) consists of the pigment (C)), but in practice is usually added in the form of a masterbatch; i.e. in the form of a composition comprising the pigment (C) and a carrier, the carrier being, for example, a polypropylene, for example a polypropylene selected from the group consisting of propylene homopolymers, propylene random copolymers (e.g. terpolymers prepared from propylene, ethylene and 1-hexene), heterophasic propylene copolymers and mixtures thereof. The concentration of the pigment (C) in such a masterbatch depends on the type of pigment, but is generally present in an amount of 0.1 to 30 wt.-%, based on the weight of the masterbatch.

[0062] The optimal amount of masterbatch depends on the type of pigment used and the concentration of the pigment in the masterbatch.The amount of masterbatch is generally 0.5 to 5.0 wt.-%, preferably 1 to 2.5 wt.-%, typically about 2 wt.-%, based on the weight of the polypropylene composition (P).

[0063] Preferably the pigment (C) is present in an amount of 0.10 to 2.5 wt.-%, more preferably in an amount of 0.10 to 1.0 wt.-%, based on the polypropylene composition (P).

[0064] For the avoidance of doubt, the term "pigment" as used herein also refers to a mixture of pigments. Examples of suitable pigments include, but are not limited to, inorganic pigments. Examples of inorganic pigments include, but are not limited to:

[0065]

[0066]

[0067] One of the common colors used for tubes is green. The green color can be achieved by using a mixture of pigments to form the pigment (C).

[0068] In one embodiment the terpolymer composition (A) may be multimodal.

[0069] For example, in this embodiment, the terpolymer composition (A) comprises a first terpolymer (A1) composed of units derived from propylene, ethylene and 1-hexene and a second terpolymer (A2) composed of units derived from propylene, ethylene and 1-hexene, and wherein the first terpolymer (A1) has a melt flow rate of 0.0030 to 1.0 dg / min as measured by ISO 1133-1:2011 at 230° C. and 2.16 kg,

[0070] wherein the second terpolymer (A2) has a melt flow rate of 0.30 to 70.0 dg / min as measured by ISO 1133-1:2011 at 230° C. and 2.16 kg,

[0071] Preferably the polypropylene composition (P)

[0072] (i) having an amount of ethylene-derived units of from 1.6 to 3.0 wt. %;

[0073] (ii) having an amount of 1-hexene-derived units of 1.7 to 4.0% by weight.

[0074] Wherein the terpolymer composition is present in the polypropylene composition (P) in an amount of at least 95 wt.-%, based on the polypropylene composition (P).

[0075] Preferably, in this embodiment the weight ratio of the first terpolymer (A1) to the second terpolymer (A2) in the polypropylene composition (P) is from 0.20 to 5.0, like from 0.25 to 4.0.

[0076] Single Reactor

[0077] The terpolymer composition (A) can be prepared by a process comprising preparing the first terpolymer (A1) and the second terpolymer (A2) in a single reactor to obtain the terpolymer composition (A). Preferably, the reactor is a gas phase reactor, more preferably the reactor is a horizontal stirred reactor.

[0078] In a preferred embodiment, the terpolymer composition (A) is prepared by a process of polymerizing propylene, ethylene and 1-hexene in the presence of a catalyst system in a horizontal stirred reactor comprising: an agitated bed for forming polymer particles,

[0079] a plurality of liquid feed inlets subsequently arranged along the top surface of the reactor above the stirred bed, the plurality of liquid feed inlets comprising a first group of liquid feed inlets and a second group of liquid feed inlets arranged after the first group of liquid feed inlets in a downstream direction of the process, and

[0080] subsequently, a plurality of gas feed inlets arranged along the bottom surface of the reactor below the stirred bed, the plurality of gas feed inlets comprising a first group of gas feed inlets and a second group of gas feed inlets arranged after the first group of gas feed inlets in a downstream direction of the process,

[0081] The method comprises the following steps:

[0082] - recovering a reactor off-gas comprising H2, propylene, ethylene and 1-hexene from the reactor,

[0083] - feeding the reactor off-gas to a condenser to form a gas-liquid mixture,

[0084] - feeding the gas-liquid mixture to a separator to obtain a first gas stream comprising H2, ethylene and propylene and a first liquid stream comprising H2, ethylene, propylene and 1-hexene, wherein fresh propylene is further fed to the separator and / or added to the first liquid stream,

[0085] - feeding the catalyst system into the reactor through an orifice arranged on the top surface of the reactor,

[0086] - feeding a H2-depleted quench liquid containing propylene into the reactor via a first set of liquid feed ports,

[0087] - feeding a H2-rich quench liquid comprising H2, ethylene and propylene and 1-hexene to the reactor via a second set of liquid feed ports, wherein the H2-rich quench liquid comprises at least part of the first liquid stream,

[0088] - feeding H2-depleted bottom gas containing fresh propylene through a first set of gas feed ports,

[0089] - feeding a H2-rich bottom gas comprising H2, ethylene and propylene through a second set of gas feed ports, wherein the H2-rich bottom gas comprises at least part of the first gas stream, and

[0090] - collecting the polymer particles formed in the stirred bed from the reactor,

[0091] in

[0092] - fresh ethylene is fed to the reactor by feeding fresh ethylene as part of the H2-depleted bottoms gas to the reactor and / or feeding fresh ethylene to a separator or adding fresh ethylene to the first gas stream, and

[0093] - feeding fresh 1-hexene to the reactor by feeding fresh 1-hexene as part of the H2-lean quench liquid to the reactor and / or feeding fresh 1-hexene to the separator or adding fresh 1-hexene to the first liquid stream.

[0094] Subsequent reactor

[0095] Alternatively, the terpolymer composition (A) may be prepared by a process comprising producing the first terpolymer (A1) and the second terpolymer (A2) as a bimodal terpolymer, wherein the bimodal terpolymer is prepared by polymerizing the first terpolymer (A1) and subsequently polymerizing the second terpolymer (A2) in the presence of the first terpolymer (A1).

[0096] Thus, in another aspect, the present invention relates to a process for preparing a polypropylene composition (P) comprising preparing a terpolymer composition by a process comprising the steps of polymerizing propylene, ethylene and 1-hexene in the presence of a Ziegler-Natta catalyst system using a first set of reaction conditions to prepare a first terpolymer (A1),

[0097] Using a second set of reaction conditions, propylene, ethylene and 1-hexene are polymerized in the presence of a Ziegler-Natta catalyst system to prepare a second terpolymer (A2),

[0098] The first set of reaction conditions and the second set of reaction conditions differ in one or more conditions selected from the group consisting of pressure, temperature, propylene concentration, ethylene concentration, 1-hexene concentration and hydrogen concentration.

[0099] Accordingly, the present invention also relates to a process for the preparation of a polypropylene composition (P), wherein the first terpolymer (A1) and the second terpolymer (A2) are prepared in a single reactor to obtain the terpolymer composition, preferably wherein the single reactor is a gas phase reactor, more preferably wherein the single reactor is a horizontal stirred reactor, preferably wherein the Ziegler-Natta catalyst system used for the preparation of the first and the second terpolymer fraction are the same.

[0100] Alternatively, the present invention provides a process for preparing a polypropylene composition (P), wherein the process comprises a sequential polymerization process comprising at least two reactors connected in series, wherein the process comprises the following steps:

[0101] - preparing a first terpolymer (A1) from propylene, ethylene and 1-hexene in a first reactor using a first set of conditions,

[0102] - transferring the first terpolymer (A1) and the unreacted comonomers of the first reactor to a second reactor,

[0103] - feeding propylene, ethylene and 1-hexene to the second reactor,

[0104] - preparing a second terpolymer (A2) in said second reactor in the presence of said first terpolymer fraction using a second set of conditions to obtain a terpolymer composition (A),

[0105] - wherein the first set of conditions and the second set of conditions differ in one or more conditions selected from the group consisting of pressure, temperature, propylene concentration, ethylene concentration, 1-hexene concentration and hydrogen concentration.

[0106] Preferably, in such a sequential polymerization process, each of the reactors is a gas phase reactor, more preferably each of the reactors is a horizontal stirred reactor.

[0107] Preferably, the Ziegler-Natta catalyst system comprises a procatalyst, a cocatalyst and an optional external electron donor, wherein the procatalyst comprises a compound of a transition metal of Groups 4 to 6 of IUPAC, a Group 2 metal compound and an internal donor, preferably wherein the internal donor is a non-phthalic acid compound. Examples of procatalysts, cocatalysts, external electron donors and internal donors are provided herein.

[0108] Blends

[0109] Alternatively, the polypropylene composition according to the present invention may be prepared by a process comprising melt blending the first terpolymer (A1) and the second terpolymer (A2) produced in different reactors to obtain the terpolymer composition (A). Preferably, each of the reactors is a gas phase reactor, for example each of the reactors is a horizontal stirred reactor.

[0110] In another embodiment, the terpolymer composition (A) may be unimodal. It is understood herein that the term 'unimodal' means that the terpolymer in the terpolymer composition is a terpolymer that is unimodal in terms of molecular weight distribution and comonomer content, and thus the copolymer can be polymerized in a single stage batch process or preferably a continuous process. The polymerization can be a slurry or gas phase, preferably a gas phase technique, such as a fluidized bed or a horizontal stirred reactor.

[0111] The unimodal terpolymer is preferably produced in one reactor. However, the unimodal terpolymer can also be produced in a multistage process, using process conditions that lead to similar polymer properties in each stage. The process conditions are substantially the same in these stages, meaning that the temperature, pressure, concentrations of reactants and catalysts are substantially the same, for example with each of these conditions not deviating by more than 10%.

[0112] Using a one-stage polymerization process is advantageous because it is a simple process using only one reactor.

[0113] For example, in a preferred embodiment the amount of terpolymer consisting of units derived from propylene, ethylene and 1-hexene in the terpolymer composition (A) is at least 95 wt.-%, based on the polypropylene composition.

[0114] The present invention also relates to a polypropylene composition (P) wherein the terpolymer composition (A) comprises the terpolymer (A1) in an amount of at least 95 wt.-%, based on the terpolymer composition,

[0115] Among them, the terpolymer (A1)

[0116] (i) consists of units derived from propylene, ethylene and 1-hexene,

[0117] (ii) having an amount of ethylene-derived units of at least 1.5% by weight; and

[0118] (iii) having an amount of 1-hexene-derived units of at least 1.5% by weight;

[0119] And for example, wherein the terpolymer (A1) has a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of 5.0 to 25.0, for example 6.0 to 22.0, wherein Mw and Mn are measured according to ASTM D6474-12, preferably wherein the terpolymer (A1) preferably has a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), wherein Mw and Mn are measured according to ASTM D6474-12.

[0120] The present invention further provides a process for preparing a polypropylene composition (P) comprising polymerizing propylene, ethylene and 1-hexene in the presence of a Ziegler-Natta catalyst system to prepare a terpolymer composition (A).

[0121] The process for preparing the polypropylene composition (P) comprises the following steps:

[0122] (a) polymerizing propylene, ethylene and 1-hexene in the presence of a Ziegler-Natta catalyst system to prepare a terpolymer,

[0123] wherein the Ziegler-Natta catalyst system comprises a procatalyst, a cocatalyst and an optional external electron donor,

[0124] Wherein the procatalyst comprises a compound of a transition metal of Groups 4 to 6 of IUPAC, a Group 2 metal compound and an internal donor, preferably wherein the internal donor is a non-phthalic compound.

[0125] The method for preparing the polypropylene composition (P) may further comprise the following steps: (b) melt blending the terpolymer composition (A), the nucleating agent (B), the optional composition comprising a pigment (C) and the optional additive (D) to form the polypropylene composition (P). The melt blending of the components may be carried out in any order. For example, (C) and (D) and optionally (B) may be mixed and then melt mixed with (A). Preferably, the composition of the present invention is made in a form that allows easy processing into a shaped article in a subsequent step, such as a pellet or granular form. The composition may be a mixture of different particles or pellets, such as a blend of a masterbatch of a heterophasic copolymer and additives. Preferably, the composition of the present invention is in the form of pellets or granules, obtained by mixing all the components in an apparatus such as an extruder; the advantage is that the composition has a uniform and well-defined concentration of additives. Melt blending means melt mixing (A) with other components at a temperature exceeding the melting point of (A). Melt blending can be carried out using techniques known to the skilled person, for example in an extruder. In general, in the method of the present invention, melt blending is carried out at a temperature of 200°C to 260°C. When an extruder is used, suitable conditions for melt blending, such as temperature, pressure, amount of shear, screw speed, and screw design are known to the skilled artisan.

[0126] Ziegler-Natta catalyst system

[0127] Preferably, the Ziegler-Natta catalyst system comprises a solid titanium-containing component in combination with at least one aluminum alkyl cocatalyst and preferably comprises an external electron donor. Examples of suitable catalyst systems are described, for example, in WO 2011 / 155999, page 7, line 16 to page 10, line 6 and page 10, line 31 to page 13, line 14, which are incorporated herein by reference.

[0128] Procatalyst

[0129] Other examples of suitable catalyst systems are described in WO2018059955. A preferred Ziegler-Natta catalyst system comprises a procatalyst, a cocatalyst and optionally an external electron donor, wherein the procatalyst is obtained by a method comprising the following steps:

[0130] Step A), providing or preparing compound R 4 z MgX 4 2-z ,in

[0131] * R 4 independently selected from a linear, branched or cyclic hydrocarbon group, the hydrocarbon group being independently selected from an alkyl group, an alkenyl group, an aryl group, an aralkyl group or an alkaryl group and one or more combinations thereof; wherein the hydrocarbon group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has 1 to 20 carbon atoms;

[0132] * X 4 independently selected from the group consisting of fluoride ion (F-), chloride ion (CI-), bromide ion (Br-) or iodide ion (I-), preferably chloride ion;

[0133] * z is greater than 0 and less than 2, that is, 0 <z<2;

[0134] Step B), compound R 4 z MgX 4 2-z With silane compound Si(OR 5 ) 4-n (R 6 ) n contact to produce a first intermediate reaction product, namely solid Mg(OR 1 ) x X 1 2-x ,in

[0135] * R 1 , R 5 and R 6 Each is independently selected from a linear, branched or cyclic hydrocarbon group, the hydrocarbon group is independently selected from an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxycarbonyl group or an alkaryl group and one or more combinations thereof; wherein the hydrocarbon group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has 1 to 20 carbon atoms;

[0136] * X 1 independently selected from the group consisting of fluoride ion (F-), chloride ion (CI-), bromide ion (Br-) or iodide ion (I-), preferably chloride ion;

[0137] * n is 0 to 4, preferably n is 0 and up to and including 1;

[0138] * z is greater than 0 and less than 2, that is, 0 <z<2;

[0139] * x is greater than 0 and less than 2, that is, 0 <x<2;

[0140] Step C), activating the solid support, comprises two steps:

[0141] Step C1), a first activation step, wherein the first intermediate reaction product obtained in step B) is contacted with at least one first activating compound and a second activating compound; the first activating compound is a compound having a formula M 1 (OR 2 ) v-w (OR 3 ) w or M 2 (OR 2 ) v-w (R 3 ) w A metal alkoxide compound, wherein: M 1 is a metal selected from the group consisting of Ti, Zr, Hf, Al or Si, M 2 is metal Si, v is M 1 or M 2 The valence of and w is less than v, R 2 and R 3 Each is a linear, branched or cyclic hydrocarbon group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkaryl and one or more combinations thereof, wherein the hydrocarbon group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has 1 to 20 carbon atoms; the second activating compound is an activated electron donor; and

[0142] Step C2), a second activation step, contacting the activated solid support obtained in step C1) with an activated electron donor to obtain a second intermediate reaction product;

[0143] Step D), reacting the second intermediate reaction product obtained in step C2) with a halogen-containing Ti compound, an optional activator (before or simultaneously with the addition of the internal donor) and at least one internal electron donor to obtain the procatalyst.

[0144] More preferred examples of the procatalyst are mentioned in the claims of WO2018059955, which is incorporated by reference. A particularly preferred procatalyst is Catalyst H used in Example 8 of WO2018059955.

[0145] Phthalate-free internal donor

[0146] Because of increasingly stringent government regulations regarding the maximum phthalate content of polymers, it is preferred to use so-called phthalate-free internal donors. In the context of the present invention, "substantially phthalate-free" or "phthalate-free" means having a phthalate content based on the total weight of the catalyst that is lower than, for example, 150ppm, alternatively lower than, for example, 100ppm, alternatively lower than, for example, 50ppm, alternatively lower than, for example, 20ppm, for example, 0ppm. Examples of phthalates include, but are not limited to, dialkyl phthalates, wherein the alkyl group contains from about two to about ten carbon atoms. Examples of phthalates include, but are not limited to, diisobutyl phthalate, ethylbutyl phthalate, diethyl phthalate, di-n-butyl phthalate, bis(2-ethylhexyl)phthalate, and diisodecyl phthalate.

[0147] Examples of phthalate-free internal donors include, but are not limited to, 1,3-diethers, such as 9,9-bis(methoxymethyl)fluorene, optionally substituted malonates, maleates, succinates, glutarates, benzoates, cyclohexene-1,2-dicarboxylates, benzoates, citraconates, aminobenzoates, silyl esters, and derivatives and / or mixtures thereof.

[0148] Activator

[0149] The catalyst system comprising the Ziegler-Natta procatalyst may be activated with an activator, for example an activator selected from the group of benzamides and monoesters, such as alkyl benzoates.

[0150] Catalyst

[0151] Catalyst system includes cocatalyst. "Cocatalyst" used herein is a well-known term in the field of Ziegler-Natta catalyst technology, and is considered to be a substance capable of converting the original catalyst into an active polymerization catalyst. Generally speaking, cocatalyst is an organometallic compound of a metal of the 1st, 2nd, 12th or 13th family containing the periodic system of elements (Handbook of Chemistry and Physics, 70th edition, CRC Press, 1989-1990). Cocatalyst may include any compound known in the art to be used as "cocatalyst", such as hydride, alkylate or arylate of aluminum, lithium, zinc, tin, cadmium, beryllium, magnesium and their combination. Cocatalyst may be a hydrocarbyl aluminum cocatalyst as known to the technician. Preferably, cocatalyst is selected from trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, diisobutyl aluminum hydride, trioctyl aluminum, dihexyl aluminum hydride and their mixture, and most preferably, cocatalyst is triethyl aluminum (abbreviated as TEAL).

[0152] External electron donor (EED)

[0153] Examples of suitable external electron donors are known to those skilled in the art and include, but are not limited to, external electron donors selected from the group consisting of compounds according to formula III (R 90 )2N-Si(OR 91 )3, having a structure according to formula IV (R 92 )Si(OR 93 )3, and mixtures thereof, wherein R 90 , R 91 , R 92 and R 93 Each of the groups is independently a linear, branched or cyclic substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably wherein R 90 , R 91 , R 92 and R 93 The groups are each independently a straight-chain unsubstituted alkyl group having 1 to 8 carbon atoms, such as ethyl, methyl or n-propyl; for example, diethylaminotriethoxysilane (DEATES), n-propyltriethoxysilane (nPTES), n-propyltrimethoxysilane (nPTMS); and alkyl groups having the general formula Si(OR a ) 4-n R b n An organosilicon compound, wherein n may be 0 to 2, and R a and R b Each of independently represents an alkyl or aryl group, optionally containing one or more heteroatoms such as O, N, S or P, having, for example, 1-20 carbon atoms; such as diisobutyldimethoxysilane (DiBDMS), tert-butylisopropyldimethoxysilane (tBuPDMS), cyclohexylmethyldimethoxysilane (CHMDMS), dicyclopentyldimethoxysilane (DCPDMS) or diisopropyldimethoxysilane (DiPDMS). More preferably, the external electron donor is selected from the group of diisopropyldimethoxysilane (DiPDMS) or diisobutyldimethoxysilane (DiBDMS).

[0154] These catalyst systems of WO2018059955 are phthalate-free. This has the advantage that undesirable phthalates will not end up in drinking water transported by pipes made of the polypropylene composition (P). Therefore, preferably, the polypropylene composition (P) and any article of the invention comprising such a composition, such as a pipe, are substantially phthalate-free. For the purposes of the present invention, substantially phthalate-free is defined as the presence of less than 0.0001% by weight of phthalates based on the composition, preferably 0.00000% by weight of phthalates based on the composition.

[0155] Preferably, the terpolymer in the terpolymer composition (A) is prepared using a Ziegler-Natta catalyst system according to the catalyst system of claim 12 of WO2018059955. In the case where the terpolymer composition (A) comprises a first terpolymer and a second terpolymer, one or both (preferably both) of the first terpolymer fraction and the second terpolymer fraction are prepared using a Ziegler-Natta catalyst system according to the catalyst system of claim 12 of WO2018059955.

[0156] The appropriate Si / Ti ratio for producing terpolymers can be easily determined by those skilled in the art, where Si / Ti is the ratio of the external electron donor to the original catalyst. The appropriate Al / Si ratio can be easily determined by those skilled in the art, where Al / Si is the ratio of the cocatalyst to the external donor. The hydrogen concentration and reaction conditions can be selected according to known standards to obtain the desired molecular weight of one or more terpolymers. The amount of ethylene and 1-hexene relative to the amount of propylene fed to the reactor can be selected according to known standards to obtain the desired amount of ethylene and 1-hexene in the terpolymer. The conditions of polymerization, such as temperature and time, pressure of the monomers, avoiding contamination of the catalyst and using additives for molecular weight are known to the technician. The temperature should be selected to ensure a reasonable copolymerization rate and avoid excessively long reactor residence time, but should not be too high to produce an unreasonable high level of stereo-random products due to excessively fast polymerization or copolymerization rate. In general, from the standpoint of achieving good catalyst performance and high productivity, the temperature is about 0 to about 120°C, and the range of about 20°C to about 95°C is preferred. More preferably, the polymerization to produce the one or more terpolymers is conducted at a temperature of about 50°C to about 80°C.

[0157] In a gas phase process, olefin copolymerization can be carried out at about atmospheric pressure or higher monomer pressure. Generally, the monomer pressure is from about 1.2 to about 40 bar (120 to 4000 kPa), more typically from 18 to 26 bar.

[0158] The copolymerization time will generally be from about 1 / 2 to several hours in a batch process, with a corresponding average residence time in a continuous process.

[0159] Prepolymerization or packaging of the catalyst or catalyst components of the present invention may also be performed prior to use in the polymerization or copolymerization of alpha olefins. A particularly useful prepolymerization procedure is described in US Pat. No. 4,579,836, which is incorporated herein by reference.

[0160] After polymerization, the polymer powder is removed from the polymerization reactor by methods known in the art and preferably transferred to a polymer finishing facility where suitable additives are incorporated into the polymer, the polymer is heated above the melt temperature in an extruder, typically by mechanical shear and added heat, extruded through a die and formed into discrete pellets. Prior to processing in the extruder, the polymer powder may be contacted with air or water vapor to deactivate any residual catalytic species.

[0161] In another aspect the present invention is directed to a polypropylene composition (P) obtainable or obtainable by the process of the present invention.

[0162] In another aspect, the present invention relates to a method for preparing a tube according to the present invention, comprising the following steps:

[0163] I. Providing a polypropylene composition (P), for example, wherein the polypropylene composition (P) is prepared by a process comprising the steps of:

[0164] (a) polymerizing propylene, ethylene and 1-hexene in the presence of a Ziegler-Natta catalyst system to prepare a terpolymer,

[0165] wherein the Ziegler-Natta catalyst system comprises a procatalyst, a cocatalyst and an optional external electron donor,

[0166] wherein the procatalyst comprises a compound of a transition metal of Groups 4 to 6 of IUPAC, a Group 2 metal compound and an internal donor, preferably wherein the internal donor is a non-phthalic acid compound, and

[0167] (b) melt blending the terpolymer composition (A), the nucleating agent (B), optionally a composition comprising a pigment (C) and optionally an additive (D) to form a polypropylene composition (P), and

[0168] II. Extruding the polypropylene composition (P) into a pipe.

[0169] A person skilled in the art knows how to run a tube extrusion process.

[0170] For example, the inventive pipe can be produced by first melting the polypropylene composition (P) in an extruder at a temperature of 200 to 300°C and subsequently extruding it through an annular die and allowing it to cool.

[0171] The extruder used to produce the tube can be, for example, a single screw extruder with an L / D of 20 to 40, or a twin screw extruder, or an extruder cascade of homogenizing extruders (single screw or twin screw). Optionally, a melt pump and / or a static mixer can additionally be used between the extruder and the annular die. Depending on the desired size of the tube, annular dies with diameters of about 16 to 2000 mm and even larger are possible.

[0172] For example, the melt arriving from the extruder is first distributed over an annular cross section via conically arranged holes and then fed to the core / die combination via a coil distributor or screen. If necessary, a flow restriction ring or other structural elements for ensuring uniform melt flow can be additionally installed before the die outlet. After leaving the annular die, the tube is removed from the shaped core, usually accompanied by air cooling and / or water cooling, optionally also using internal water cooling to cool the tube.

[0173] In another aspect the present invention is directed to an article comprising the polypropylene composition (P) according to any one of claims.

[0174] Preferably, the present invention is directed to an article, wherein the article comprises the polypropylene composition (P) in an amount of at least 95 wt.-%, based on the article.

[0175] More preferably, the present invention relates to a pipe, wherein the pipe comprises the polypropylene composition (P), preferably wherein the pipe comprises at least 95 wt.-%, such as at least 96 wt.-%, such as at least 97 wt.-%, such as at least 98 wt.-%, such as at least 99 wt.-% of the polypropylene composition (P). For example, the polypropylene composition (P) may be present in an amount of 100 wt.-%, based on the pipe, i.e. the pipe consists of the polypropylene composition (P).

[0176] In another aspect, the invention relates to the use of a composition according to the invention for the preparation of a pipe.

[0177] It is noted that the present invention relates to subject matter defined in the independent claims individually or in combination in any possible combination of the features described herein, preferably in particular those combinations of features presented in the claims. Thus, it is to be understood that all combinations of features relating to the composition according to the invention, all combinations of features relating to the method according to the invention, as well as all combinations of features relating to the composition according to the invention and all combinations of features relating to the method according to the invention are described herein.

[0178] It is further noted that the terms 'comprising', 'including', 'containing' do not exclude the presence of other elements. However, it is also understood that a description of a product / composition comprising certain components also discloses a product / composition consisting of these components. A product / composition consisting of these components may be advantageous because it provides a simpler and more economical method for preparing the product / composition. Similarly, it is also understood that a description of a method comprising certain steps also discloses a method consisting of these steps. A method consisting of these steps may be advantageous because it provides a simpler and more economical method.

[0179] The present invention is now illustrated with the aid of the following examples, but the invention is not limited thereto. Example

[0180] method

[0181] SEC: Mz, Mn, Mw

[0182] The particle samples were subjected to size exclusion chromatography (SEC), and Mw, Mn, and Mz were measured according to ASTM D6474-12 (Standard Test Method for Molecular Weight Distribution and Molecular Weight Averages of Polyolefins by High Temperature Gel Permeation Chromatography). Mw represents the weight average molecular weight and Mn represents the number average weight. Mz represents the z average molecular weight.

[0183] In addition to the method specified by ASTM D6474-12, the method was carried out using a configuration in which a Polymer Char IR5 infrared concentration detector and a Polymer Char in-line viscosity detector were used to obtain 'absolute' (and therefore more precise) molar masses. Three columns of Polymer Laboratories 13 μm PLgel Olexis 300×7.5 mm were used in series with 1,2,4-trichlorobenzene stabilized with 1 g / L butylcresol (also known as 2,6-di-tert-butyl-4-methylphenol or BHT) as the eluent.

[0184] The molar mass distribution and the derived molar mass are determined based on calibration using linear PE standards (narrow and broad (Mw / Mn=4 to 15)) ranging from 0.5 to 2800 kg / mol. A sample of polymer particles is mixed with tris(2,4-di-tert-butylphenyl)phosphite (Irgafos 168) and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (Topanol CA) in a weight ratio of 1:1:1 sample:Irgafos:Topanol, after which the mixture thus obtained is dissolved in 1,2,4-trichlorobenzene stabilized with 1 g / L BHT until the concentration of the mixture in 1,2,3-trichlorobenzene stabilized with 1 g / L BHT is 0.03 wt%.

[0185] Xylene solubles (XS)

[0186] To evaluate the XS (xylene solubles weight %) of the powder sample, 1 gram of polymer and 100 ml of xylene were introduced into a glass flask equipped with a magnetic stirrer. The temperature was raised to the boiling point of the solvent. The clear solution thus obtained was then kept under reflux and stirred for another 15 min. Heating was stopped and the separating plate between the heating and the flask was removed. Cooling was performed with stirring for 5 min. The closed flask was then kept in a 25° C. thermostatic water bath for 30 min. The solid thus formed was filtered through filter paper. 25 ml of the filtered liquid was poured into a pre-weighed aluminum container, which was heated in a 140° C. stove under nitrogen flow and vacuum for at least 2 hours to remove the solvent by evaporation. The container was then kept in a baking oven at 140° C. under vacuum until constant weight was obtained. The weight percentage of the polymer soluble in xylene at room temperature was then calculated.

[0187] C2, C6 comonomer content 13 C-NMR

[0188] About 150 mg of sample was dissolved in 3 ml of 1,1,2,2-tetrachloroethane-d2 (TCE-d2) / BHT stock solution at about 135°C using a 10 mm NMR tube. The stock solution was made by dissolving about 5 mg of BHT in 25 ml of TCE-d2. The tube was purged with nitrogen for about 1 min before dissolution to reduce the oxygen concentration in the tube. The sample was checked for homogeneity regularly and mixed manually if necessary.

[0189] All NMR experiments were performed on a Bruker 500Avance III HD spectrometer equipped with a 10 mm DUAL (proton and carbon) cryogenically cooled probe head operating at 125° C. 13C NMR measurements were performed using a spectral width of 220 ppm, an acquisition time of approximately 1.4 s, and a relaxation delay of 20 s between every 512 transients. The spectrum was calibrated by setting the central signal of the TCE triplet at 74.2 ppm.

[0190] Comonomer content was calculated as described in FFN Escher, GB Galland, J Polym Sci Part A: Polym Chem 42:2474-2482, 2004.

[0191] Dynamic force spectroscopy (DMS) analysis of PI (polydispersity index)

[0192] Compression molding of the samples was carried out at 200° C. in successive steps: 1 minute at 0 bar, 1 minute at 5 bar, 3 minutes at 40 bar and ended by a cooling step at 40 bar. The rheological behavior of the samples was studied using a DHR2 torsion rheometer (TA Instruments) equipped with parallel plate geometry (diameter=25 mm, gap=1000 μm). The rheological profile was obtained by performing an oscillating frequency sweep experiment. The measurements were performed using the following program:

[0193] a) a conditioning step at 230°C for 60 seconds,

[0194] b) Oscillating frequency sweep at 230°C: frequency 600-0.01 rad / s, 1% strain, logarithmic sweep, 5 pts / decade.

[0195] The twist torque-displacement data points were determined for each sample. The undistorted rheological data collected in oscillatory mode were converted to flow mode data using the Cox-Merz law and Trios software. The converted rheological curves were fitted using the Yasuda-Carreau model, from which zero shear viscosity values ​​were obtained. From these values, the 10 5 The rheological polydispersity index (PI) of a blend is determined by dividing Pa by the crossover modulus (occurring when the storage modulus (G') and the loss modulus (G") are equal. This is a convenient measure of polydispersity that is often used. The PI value can be determined for all polymer blends without extrapolating the crossover point. PI is calculated as follows:

[0196] G occurs when (G') storage modulus = (G") loss modulus c

[0197] Melt flow rate (MFR)

[0198] For the purposes of the present invention, melt flow rate is the melt flow rate measured according to ISO 1133 (2.16 kg / 230° C.).

[0199] <gp> / Y< / gp>

[0200] The strain hardening modulus divided by the yield stress ( <gp> / Y):

[0201] a) providing a test specimen of the composition by compression molding the composition into a sheet having a thickness of 0.3 mm ± 0.025 mm according to ISO 1873-2 and punching the sheet into a test specimen having the test specimen geometry described in ISO / DIS 18488, wherein after compression molding and before punching, the sheet is annealed at a temperature of 100° C. for 1 hour and cooled to room temperature,

[0202] b) Elongate the sample at a constant transverse speed of 20 mm / min at 100°C,

[0203] c) measuring the load on the specimen during elongation to obtain a stress-strain curve and measure the yield stress Y,

[0204] d) calculating the true stress-true strain curve from the stress-strain curve obtained in step c) according to the method described in ISO / DIS18488, and calculating the tensile strain hardening modulus from the true stress-strain curve <G p >, and

[0205] e) Calculation of tensile strain hardening modulus <G p >divided by the quotient of the yield stress Y.

[0206] Steps b) and c) are carried out as follows:

[0207] - Measure the exact dimensions of width (b, accuracy 0.01 mm) and thickness (h, accuracy 0.005 mm) of each individual specimen.

[0208] - Before starting the test, condition the sample in a temperature test chamber set at a predetermined temperature of 100°C for a period of time, for example at least 30 minutes.

[0209] - Clamp the specimen in the upper jaw of the elongation device. Choose the clamp to avoid specimen damage and slippage.

[0210] - Closed high and low temperature test chamber.

[0211] - After reaching said predetermined temperature, the test piece is clamped by the lower grip.

[0212] - Before applying the load and starting the measurement, the sample should remain between the grips for a certain period of time, for example at least 1 minute.

[0213] - Apply a prestress of, for example, 0.4 MPa, achieved at a speed of, for example, 5 mm / min.

[0214] - During the test, the load and elongation of the specimen are measured.

[0215] - Extend the specimen at a constant transverse speed of 20 mm / min until the specimen breaks.

[0216] For step d), the method of calculation is described in ISO / DIS 18488 Chapter 8 "Data Processing".

[0217] The stretch ratio λ is calculated from the length l and the gauge length l0 as shown in Equation 1.

[0218]

[0219] in

[0220] Δl is the increase in specimen length between the locating marks.

[0221] Calculate the true stress σ according to Eq. 真 , which follows from the assumption of conservation of volume between the positioning lines:

[0222]

[0223] in

[0224] F is the measured force (N).

[0225] It is important that the initial cross-section A be determined for each individual test bar.

[0226] The Neo-Hookean constitutive model (Eq. 3, see Annex A of ISO / DIN 18488) was used to fit and extrapolate the data, thereby calculating the <gp>(MPa).

[0227]

[0228] in

[0229] C is a mathematical parameter of the constitutive model, describing the yield stress extrapolated to λ=0.

[0230] A data fitting accuracy (R2) greater than 0.9 should be achieved.

[0231] G was performed on the test specimens prepared according to ISO 1873-2 and ISO / DIS 18488 at a constant transverse speed of 20 mm / min and a temperature of 100 °C. p / Y measurement.

[0232] Tube impact measurement (tube impact)

[0233] The tube impact measurements were carried out according to DIN 8078 (2008) on tubes prepared as described below. The temperature indicated is the lowest temperature at which at most 1 tube out of 10 failed.

[0234] Pipe static pressure test (pipe pressure)

[0235] The failure-free running time of the pipe prepared as described below is measured when a hoop stress of 4.2 MPa measured according to ISO 3213:2009 at a temperature of 95°C (or 7.5 MPa hoop stress at 70°C, or 13.0 MPa hoop stress at 20°C, or 15.5 MPa hoop stress at 20°C) is applied to the pipe according to ISO 1167-1:2006.

[0236] Example

[0237] The procatalyst used to prepare one or more terpolymers is the procatalyst H (Example 8) of WO2018 / 059955A1. The composition of the produced solid procatalyst H is given in Table 1.

[0238] Table 1. Composition of solid procatalyst H

[0239] catalyst Example d50[μm] Mg[%] Ti[%] ID [%] Activator (EB) [%] EtO[%] H 8 22.16 19.65 2.40 8.41 6.68 1.48

[0240] The polymerization to produce terpolymer 1 (Trimer 1) and terpolymer 2 (Trimer 2) was carried out in a gas phase fluidized bed polymerization reactor using the above-mentioned procatalyst.

[0241] The polymerization to produce terpolymer 3 (Trimer 3) was carried out in a horizontal gas phase polymerization reactor using the above catalyst.

[0242] For all examples, triethylaluminium (TEAL) was used as a co-catalyst. Different external electron donors (EED) were used: ADT5500 (commercially available from Grace) was used for trimer 1 and trimer 2, diisopropyl-dimethoxysilane (P donor) was used for trimer 3.

[0243] The reactor conditions for the different terpolymers are described below in Table 2. The resulting properties of the terpolymers measured as described herein are shown in Table 4.

[0244] Table 2. Process conditions

[0245] Trimer 1 Trimer 2 Trimer 3 EED ADT 5500 ADT 5500 P Donor Al / Si Molar Ratio 2.7 2.7 3.3 Al / Ti Molar Ratio 110 110 50 T C 66 66 68 P Barg 26 26 18 H2 / C3 mol / mol 0.004 0.003 0.006 C2 / C3 mol / mol 0.012 0.011 0.015 C6 / C3 mol / mol 0.022 0.02 0.015 Properties of the produced powder XS weight% 5.3 4.9 5.3 TC2 weight% 2.6 1.5 3.0 TC6 weight% 2.5 2.2 2.2 Weight ratio TC2 / TC6 1.04 0.68 1.4 Mw / Mn - 9.4 9.5 9.5

[0246] Al / Ti is the molar ratio of co-catalyst (TEAL) to procatalyst.

[0247] Al / Si is the molar ratio of co-catalyst (TEAL) to external electron donor (EED).

[0248] H2 / C3 is the molar ratio of hydrogen to propylene.

[0249] C2 / C3 is the molar ratio of ethylene to propylene.

[0250] C6 / C3 is the molar ratio of 1-hexene to propylene.

[0251] TC2 is the total amount of ethylene derived units in the produced powder composition.

[0252] TC6 is the total amount of 1-hexene derived units in the produced powder composition.

[0253] The powder was collected and pellets were prepared in a twin screw Krauss Maffei Berstdorff extruder by melt blending the powder with additives (see Table 3 below). The temperature profile of the extruder (ZE25 / 43D) was: 20, 20, 30, 50, 150, 180, 210 (3x), 225, 260, 260° C. The throughput was 13 kg / hr.

[0254] Additives (antioxidants, acid scavengers) were used in the amounts shown in Table 3 below showing granule details and were mixed before dosing into the extruder.

[0255] rPP: Random propylene-ethylene copolymer, can be used as Vestolen P 9421 is commercially available from SABIC.

[0256] HPN20 is commercially available from Milliken & Company HPN20-E.

[0257] CMB is a masterbatch composition consisting of:

[0258] 58.8 wt% propylene homopolymer 595P having a melt flow rate of 10.5 dg / min measured using ISO 1133-1:2011 at 230°C and 2.16 kg, commercially available from SABIC,

[0259] 25 wt% zinc sulfide (CAS No. 1314-98-3),

[0260] 13.3 wt% CI Pigment Brown 24 (CAS No. 68186-90-3),

[0261] 2.67 wt% CI Pigment Green 7 (CAS No. 1328-53-6) and

[0262] 0.19 wt% CI Pigment Black 7 (CAS 1333-86-4).

[0263] 1010 (1010) is a phenolic antioxidant (PA) pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and is commercially available from BASF.

[0264] 168 (168) is tris(2,4-di-tert-butylphenyl)phosphite, has CAS number 31570-04-4, and is commercially available from BASF.

[0265] 1330 (1330) is a phenolic antioxidant, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and is commercially available from BASF.

[0266] Table 3. Polypropylene composition (granules)

[0267] E1 E2 E3 CE1 CE2 CE3 CE4 CE5 Trimer 1 weight% 98.95 98.95 Trimer 2 weight% 98.95 Trimer 3 weight% 98.95 97.95 98.95 97.95 R 98.95 HPN 20 weight% 0.05 0.05 0.05 CMB weight% 1.0 1.0 1010 weight% 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 168 weight% 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 1330 weight% 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Calcium stearate weight% 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05

[0268] Tube preparation

[0269] 20×3.4 mm tubes were extruded on a Reifenhauser S50 1 with a barrier screw running at 35 rpm. The die temperature profile was set to 40 / 190 / 200 / 205 / 205° C. and the extruder temperature profile was set to 205 / 205 / 205 / 205° C. The extruded tube was cooled to a temperature of 20° C. The tube impact and tube pressure were then measured on the tube as described above.

[0270] Table 4. Results

[0271]

[0272] * D = Ductile failure

[0273] *B=brittle failure

[0274] As can be seen from Table 4 the polypropylene composition according to the present invention has a combination of high pipe impact resistance (Pipe Impact) and high pipe static pressure resistance (Pipe Pressure).< / gp> < / gp> < / gp> < / gp> < / gp> < / gp> < / gp>

Claims

1. A pipe comprising a polypropylene composition comprising a terpolymer composition, a nucleating agent and optionally a composition comprising a pigment, wherein the terpolymer composition comprises at least one terpolymer prepared from propylene, ethylene and 1-hexene, wherein the nucleating agent is a nucleating agent comprising a metal salt of hexahydrophthalic acid represented by formula (I), wherein M1 and M2 are the same or different and can be combined into a cation and are selected from at least one metal cation of calcium, strontium, lithium and monovalent aluminum; and wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 are the same or different and are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogen, and phenyl, wherein the polypropylene composition has a melt flow rate of 0.10 to 0.70 dg / min as measured by ISO 1133-1:2011 at 230° C. and 2.16 kg, wherein the amount of ethylene-derived units in the polypropylene composition is from 1.6 to 3.0 wt. % and the amount of 1-hexene-derived units in the polypropylene composition is from 1.7 to 4.0 wt. %; and TC2 ≥ TC6-0.20, wherein TC2 represents the total amount of ethylene derived units in the polypropylene composition in wt.%, and wherein TC6 represents the total amount of 1-hexene derived units in the polypropylene composition in wt.%.

2. A pipe comprising a polypropylene composition according to claim 1, wherein the weight ratio of the total amount of ethylene derived units in the polypropylene composition to the total amount of 1-hexene derived units in the polypropylene composition is at least 0.70 and / or at most 3.

0.

3. A pipe comprising a polypropylene composition according to claim 1, wherein the weight ratio of the total amount of ethylene derived units in the polypropylene composition to the total amount of 1-hexene derived units in the polypropylene composition is at least 0.80 and / or at most 2.

5.

4. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a melt flow rate of 0.10 to 0.50 dg / min, measured by ISO 1133-1:2011 at 230°C and 2.16 kg.

5. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a melt flow rate of 0.10 to 0.30 dg / min, measured by ISO 1133-1:2011 at 230°C and 2.16 kg.

6. A pipe comprising a polypropylene composition according to any one of claims 1-3, wherein the amount of ethylene derived units in the polypropylene composition is from 1.8 to 2.8 wt%.

7. A pipe comprising a polypropylene composition according to any one of claims 1-3, wherein the amount of 1-hexene derived units in the polypropylene composition is from 1.7 to 3.5 wt%.

8. A pipe comprising a polypropylene composition according to any one of claims 1-3, wherein the amount of 1-hexene derived units in the polypropylene composition is from 1.8 to 3.0 wt%.

9. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein TC2 ≥ TC6-0.10, wherein TC2 represents the total amount of ethylene derived units in the polypropylene composition in wt.%, and wherein TC6 represents the total amount of 1-hexene derived units in the polypropylene composition in wt.%.

10. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein TC2>TC6, wherein TC2 represents the total amount of ethylene derived units in the polypropylene composition in wt.%, and wherein TC6 represents the total amount of 1-hexene derived units in the polypropylene composition in wt.%.

11. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a ratio of weight average molecular weight Mw to number average molecular weight Mn of 5.0 to 25.0, wherein Mw and Mn are measured according to ASTM D6474-12; and / or wherein the polypropylene composition has a polydispersity index PI of 4.0 to 15.0, wherein the PI is calculated by 10 5 Pa is determined by dividing the crossover modulus Gc, wherein Gc occurs when the storage modulus G' and the loss modulus G" are equal, and wherein G' and G" are measured using dynamic force spectroscopy.

12. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a ratio of weight average molecular weight Mw to number average molecular weight Mn of 6.0 to 22.0, wherein Mw and Mn are measured according to ASTM D6474-12; and / or wherein the polypropylene composition has a polydispersity index PI of 5.0 to 15.0, wherein the PI is a function of the molecular weight of the polypropylene composition. 5 Pa is determined by dividing the crossover modulus Gc, wherein Gc occurs when the storage modulus G' and the loss modulus G" are equal, and wherein G' and G" are measured using dynamic force spectroscopy.

13. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a ratio of weight average molecular weight Mw to number average molecular weight Mn of 7.0 to 20.0, wherein Mw and Mn are measured according to ASTM D6474-12; and / or wherein the polypropylene composition has a polydispersity index PI of 6.5 to 12.0, wherein the PI is calculated by 10 5 Pa is determined by dividing the crossover modulus Gc, wherein Gc occurs when the storage modulus G' and the loss modulus G" are equal, and wherein G' and G" are measured using dynamic force spectroscopy.

14. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the polypropylene composition has a molecular weight of at least 7.

0. <gp> / Y, where <gp>represents the strain hardening modulus and Y represents the yield stress, and where <gp> / Y is determined as follows:< / gp> < / gp> < / gp> a) providing a test specimen of the polypropylene composition by compression molding the composition into a sheet having a thickness of 0.3 mm ± 0.025 mm according to ISO 1873-2 and punching the sheet into a test specimen having a test specimen geometry as described in ISO / DIS 18488, wherein after the compression molding and before the punching, the sheet is annealed at a temperature of 100° C. for 1 hour and cooled to room temperature, b) stretching the sample at 100° C. at a constant transverse speed of 20 mm / min, c) measuring the load on the sample during the elongation to obtain a stress-strain curve and measuring the yield stress Y, d) calculating the true stress-true strain curve from the stress-strain curve obtained in step c) according to the method described in ISO / DIS18488, and calculating the tensile strain hardening modulus from the true stress-strain curve <gp> ,and< / gp> e) Calculating the tensile strain hardening modulus <gp> Divide the quotient by the yield stress Y.< / gp> 15. The pipe comprising a polypropylene composition according to claim 14, wherein the polypropylene composition has a <gp> / Y。< / gp> 16. The pipe comprising a polypropylene composition according to claim 14, wherein the polypropylene composition has a <gp> / Y。< / gp> 17. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the lowest temperature at which at most 1 pipe out of 10 pipes made of the composition fails as determined by DIN 8078 (2008) is 0.0°C.

18. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the lowest temperature at which at most 1 pipe out of 10 pipes made of the composition fails as determined by DIN 8078 (2008) is -1.0°C.

19. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the lowest temperature at which at most 1 pipe out of 10 pipes made of the composition fails as determined by DIN 8078 (2008) is -2.0°C.

20. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the lowest temperature at which at most 1 pipe out of 10 pipes made of the composition fails as determined by DIN 8078 (2008) is -3.0°C.

21. The pipe comprising the polypropylene composition according to any one of claims 1 to 3, wherein the lowest temperature at which at most 1 pipe out of 10 pipes made of the composition fails as determined by DIN 8078 (2008) is -4.0°C.

22. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the nucleating agent comprises a cyclic dicarboxylate compound having formula (II), And / or wherein the nucleating agent is present in an amount of 10 to 5000 ppm based on the polypropylene composition.

23. The pipe comprising a polypropylene composition according to claim 22, wherein the nucleating agent is present in an amount of 100 to 2500 ppm based on the polypropylene composition.

24. The pipe comprising the polypropylene composition according to any of claims 1-3, wherein the pigment is an inorganic pigment and / or wherein the pigment is present in an amount of 0.10 to 2.5 wt.-%, based on the polypropylene composition.

25. The pipe comprising the polypropylene composition according to any of claims 1-3, wherein the sum of the amounts of the terpolymer composition, the nucleating agent and the composition comprising the pigment is at least 95 wt.-%, based on the polypropylene composition.

26. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the terpolymer composition comprises a first terpolymer consisting of units derived from propylene, ethylene and 1-hexene and a second terpolymer consisting of units derived from propylene, ethylene and 1-hexene, and wherein the first terpolymer has a melt flow rate of 0.0030 to 1.0 dg / min as measured by ISO 1133-1:2011 at 230° C. and 2.16 kg, wherein the second terpolymer has a melt flow rate of 0.30 to 70.0 dg / min as measured by ISO 1133-1:2011 at 230° C. and 2.16 kg.

27. The pipe comprising a polypropylene composition according to claim 26, wherein the polypropylene composition (i) having an amount of ethylene-derived units of from 1.6 to 3.0 wt. %; (ii) having an amount of 1-hexene-derived units of 1.7 to 4.0 wt.%, Wherein the terpolymer composition is present in the polypropylene composition in an amount of at least 95 wt.-%, based on the polypropylene composition.

28. The pipe comprising the polypropylene composition according to claim 26, wherein the weight ratio of the first terpolymer to the second terpolymer in the polypropylene composition is from 0.20 to 5.

0.

29. The pipe comprising the polypropylene composition according to claim 26, wherein the weight ratio of the first terpolymer to the second terpolymer in the polypropylene composition is from 0.25 to 4.

0.

30. A pipe comprising a polypropylene composition according to any one of claims 1 to 3, wherein the amount of the terpolymer consisting of units derived from propylene, ethylene and 1-hexene in the terpolymer composition is at least 95 wt.%, based on the polypropylene composition. wherein the terpolymer composition comprises the first terpolymer in an amount of at least 95 wt. %, based on the terpolymer composition, wherein the first terpolymer (i) consists of units derived from propylene, ethylene and 1-hexene, (ii) having an amount of ethylene-derived units of at least 1.5% by weight; and (iii) having an amount of 1-hexene-derived units of at least 1.5% by weight.

31. The pipe comprising a polypropylene composition according to claim 30, wherein the first terpolymer has a ratio of weight average molecular weight Mw to number average molecular weight Mn of 7.0 to 20.0, wherein Mw and Mn are measured according to ASTM D6474-12.

32. The pipe comprising a polypropylene composition according to claim 30, wherein the first terpolymer has a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of 8.0 to 16.0, wherein Mw and Mn are measured according to ASTM D6474-12.

33. A pipe comprising the polypropylene composition according to any one of claims 1-3, wherein the pipe comprises the polypropylene composition in an amount of at least 95 wt.-%, based on the pipe.

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