propylene ethylene copolymer

Abstract

A propylene-ethylene copolymer having: i) a xylene-soluble fraction ranging from 30% to 48% by weight at 25°C; ii) an intrinsic viscosity ranging from 2.8 dl / g to 4.3 dl / g of the xylene-soluble fraction at 25°C; iii) a viscosity according to ISO... 1133 The melt flow rate (MFR) measured at 230 °C and a load of 2.16 kg ranges from 0.2 g / 10 min to 10 g / 10 min; iv) the ethylene derivative content ranges from 10.3 wt% to 15.4 wt%; v) the ethylene derivative content in fractions insoluble in xylene at 25 °C ranges from 6.1 wt% to 9.0 wt%; vi) the ethylene derivative content in fractions soluble in xylene at 25 °C ranges from 18.2 wt% to 30.2 wt%; vii) the ethylene derivative content in fractions insoluble in xylene at 25 °C ranges from 4.1 mol% to 6.5 mol%. 13 C-NMR sequences of PEP, and measurements of fractions soluble in xylene at 25 °C ranging from 10.5 mol% to 14.2 mol%. 13 C-NMR sequence PEP.

Description

Technical Field

[0001] This disclosure relates to a flexible propylene-ethylene copolymer for articles, sheets or films used in roofing and geomembranes, particularly suitable for synthetic flame-retardant roofing films for roofing coverings, combining better processability, improved flexibility and good mechanical and weldability properties. Background Technology

[0002] Due to the typically valuable properties of polyolefins, such as chemical inertness, mechanical properties and non-toxicity, polyolefin compositions that possess elastic properties while maintaining good thermoplastic behavior have been used in many applications.

[0003] Furthermore, they can be advantageously converted into finished products using the same techniques used for thermoplastic polymers.

[0004] For example, EP-A-472 946 describes a flexible elasto-plastic polyolefin composition comprising, by weight: A) 10 to 50 parts of isotactic propylene homopolymer or copolymer; B) 5 to 20 parts of an ethylene copolymer insoluble in xylene at room temperature; and C) 40 to 80 parts of an ethylene / propylene copolymer containing less than 40% by weight of ethylene and soluble in xylene at room temperature; the intrinsic viscosity of said copolymer is preferably from 1.7 dl / g to 3 dl / g. The composition is relatively flexible and has good elastic properties, as demonstrated by a flexural modulus below 150 MPa, a Shore D hardness from 20 to 35, and a Shore A hardness of about 90, which are associated with good tensile deformation values ​​(20% to 50% at 75% elongation and about 33% to 40% at 100% elongation); however, such values ​​are not entirely satisfactory for many applications.

[0005] International application WO03 / 01 1962 describes a more flexible elasto-plastic polyolefin composition, and includes, by weight:

[0006] A) 8% to 25% of crystalline polymer fractions selected from propylene homopolymers and copolymers of propylene with C4 to C8 α-olefins;

[0007] B) 75% to 92% of an elastomer fraction comprising two different propylene elastomer copolymers, and more specifically: (1) a first elastomer copolymer of propylene with 15% to 32% of ethylene and / or C4 to C8 α-olefins, and (2) a second elastomer copolymer of propylene with more than 32% to up to 45% of ethylene and / or C4 to C8 α-olefins, the weight ratio of (1) / (2) ranging from 1:5 to 5:1.

[0008] These polyolefin compositions have a flexural modulus of less than 60 MPa, a Shore A of less than 90, and a tensile deformation of less than 35% at 100% elongation.

[0009] International application WO2012 / 152803 discloses a polyolefin composition suitable for roofing membranes that has improved flexibility and extensibility at low temperatures, wherein a flexible multiphase composition (I) with a wide molecular weight distribution obtained by blending multiphase compositions with different melt flow indices is further blended with an elastomer component and highly filled with a flame retardant.

[0010] It remains believed that propylene-ethylene copolymers need to demonstrate an improved balance of properties, particularly in applications such as single-layer roofing membranes, where flexibility and ductility, as well as processability, are required without unduly degrading other mechanical properties, such as tensile properties and weldability, in particular. High puncture and tear resistance, as required, are also desirable in membranes used for roofing coverings. Summary of the Invention

[0011] Therefore, this disclosure provides a propylene-ethylene copolymer having:

[0012] i) Xylene-soluble fraction ranging from 30% to 48% by weight at 25°C;

[0013] ii) The intrinsic viscosity of the xylene-soluble fraction in tetrahydronaphthalene, measured at 135 °C, ranging from 2.8 dl / g to 4.3 dl / g;

[0014] iii) Melt flow rate (MFR) measured in accordance with ISO 1133-1:2012 at 230°C and a load of 2.16 kg, ranging from 0.2 g / 10 min to 10 g / 10 min;

[0015] iv) through 13 C-NMR measurements were performed on ethylene-derived units ranging from 10.3 wt% to 15.4 wt%.

[0016] v) By 13 C-NMR measurements of fractions insoluble in xylene at 25 °C ranged from 6.1 wt% to 9.0 wt% of ethylene-derived units.

[0017] vi) Through 13 C-NMR measurements of xylene-soluble fractions at 25 °C ranged from 18.2 wt% to 30.2 wt% in ethylene-derived units.

[0018] vii) The fractions insoluble in xylene at 25°C were measured in the range of 4.1 mol% to 6.5 mol%. 13PEP C-NMR sequence, and fractions soluble in xylene at 25 °C ranging from 10.5 mol% to 14.2 mol%. 13 C-NMR sequence PEP. Detailed Implementation

[0019] Therefore, this disclosure provides a propylene-ethylene copolymer having:

[0020] i) a xylene soluble fraction in the range of 30% to 48% at 25°C, preferably from 33% to 45% and more preferably from 35% to 42% at 25°C;

[0021] ii) The intrinsic viscosity of the xylene-soluble fraction in tetrahydronaphthalene, measured at 135°C, ranging from 2.8 dl / g to 4.3 dl / g, preferably from 3.0 dl / g to 4.0 dl / g, and more preferably from 3.2 dl / g to 3.8 dl / g;

[0022] iii) The melt flow rate (MFR) measured according to ISO 1133-1:2012 at 230°C and a load of 2.16 kg is in the range of 0.2 g / 10 min to 10 g / 10 min, preferably from 0.3 g / 10 min to 8.0 g / 10 min, and more preferably from 0.4 g / 10 min to 6.0 g / 10 min;

[0023] iv) through 13 The C-NMR measurement ranges from 10.3 wt% to 15.4 wt%, preferably from 11.2 wt% to 14.4 wt%, and more preferably from 11.9 wt% to 13.4 wt% of ethylene-derived unit content;

[0024] v) By 13 C-NMR measurements of fractions insoluble in xylene at 25°C range from 6.1 wt% to 9.0 wt%, preferably from 6.3 wt% to 8.3 wt%, and more preferably from 6.5 wt% to 8.2 wt% of ethylene-derived units.

[0025] vi) Through 13 C-NMR measurements of xylene-soluble fractions at 25°C range from 18.2 wt% to 30.2 wt%, preferably from 20.2 wt% to 27.8 wt%, and more preferably from 22.2 wt% to 26.5 wt% of ethylene-derived unit content.

[0026] vii) The fraction measured at 25°C that is insoluble in xylene is in the range of 4.1 mol% to 6.5 mol%, preferably in the range of 4.3 mol% to 6.0 mol%, and more preferably in the range of 4.8 mol% to 6.0 mol%. 13 The C-NMR sequence of PEP; and the fraction measured at 25°C soluble in xylene in the range of 10.5 mol% to 14.2 mol%, preferably from 10.9 mol% to 13.8 mol%, more preferably from 11.5 mol% to 13.5 mol%. 13 PEP C-NMR sequence;

[0027] For the purposes of this disclosure, the term "polymer" refers to a polymer containing only two comonomers (such as propylene and ethylene).

[0028] Preferably, in the propylene-ethylene copolymer, the fractions soluble in xylene at 25°C are measured. 13 The PEE range of the C-NMR sequence is from 10.3 mol% to 13.0 mol%, with a preferred range of 10.8 mol% to 12.5 mol%.

[0029] Preferably, in the propylene-ethylene copolymer, the fractions soluble in xylene at 25°C are measured. 13 The C-NMR sequence EEE is less than 9.0 mol%, preferably in the range of 4.5 mol% to 8.5 mol%.

[0030] The propylene-ethylene copolymer is obtained through a process carried out in a reactor with two interconnected polymerization zones (a riser and a downcomer), in which the polymer particles grow:

[0031] (a) The first (riser) of the polymerization zone flows under rapid fluidization conditions in the presence of propylene and ethylene;

[0032] (b) They leave the riser and enter the second (downstream) in the polymerization zone, flowing downward through the downstream in a densified form in the presence of propylene and ethylene, wherein the ethylene concentration in the downstream is higher than the ethylene concentration in the riser.

[0033] (c) The polymer is removed from the downcomer and reintroduced into the riser, thereby establishing a polymer circulation between the riser and the downcomer.

[0034] In the first polymerization zone (riser), rapid fluidization conditions are established by feeding a gas mixture comprising one or more α-olefins at a rate higher than the conveying velocity of the polymer particles. The velocity of the gas mixture typically includes between 0.5 m / s and 15 m / s, preferably between 0.8 m / s and 5 m / s. The terms “conveying velocity” and “rapid fluidization conditions” are well known in the art; their definitions can be found, for example, in D. Geldart, Gas Fluidisation Technology, pp. 155 ff., J. Wiley & Sons Ltd., 1986.

[0035] In the second polymerization zone (downcomer), polymer particles flow in a densified form under gravity, resulting in a high solids density (mass of polymer per reactor volume), which is close to the bulk density of the polymer. Throughout this specification, the term "densified form" of the polymer implies a ratio between the mass of the polymer particles and the reactor volume that is greater than 80% of the resulting "cast bulk density" of the polymer. The "cast bulk density" of the polymer is a parameter well known to those skilled in the art. Given the foregoing, it is clear that in the downcomer, the polymer flows downward in a piston-like flow, and the polymer particles carry only a small amount of gas.

[0036] According to the process disclosed herein, two interconnected polymerization zones operate in such a way that the gas mixture from the riser is completely or partially prevented from entering the downcomer by introducing a liquid and / or gas stream, called a “barrier flow,” having a composition different from the gaseous mixture present in the riser, into the upper portion of the downcomer. To conform to this process characteristic, one or more feed lines for the barrier flow are placed in the downcomer, close to the upper limit of the volume occupied by polymer particles flowing downward in a densified form.

[0037] The liquid / gas mixture fed into the upper portion of the downcomer partially replaces the gas mixture entrained by the polymer particles entering the downcomer. Partial evaporation of the liquid in the barrier flow generates a gas stream in the upper portion of the downcomer that moves countercurrently to the descending polymer flow, thus acting as a barrier to the gas mixture originating from the riser and entrained between the polymer particles. The liquid / gas barrier fed into the upper portion of the downcomer can be sprayed onto the surface of the polymer particles: the evaporation of the liquid provides the desired upward gas flow.

[0038] The barrier flow feed causes differences in monomer and / or hydrogen (molecular weight regulator) concentrations inside the riser and downcomer, enabling the production of bimodal polymers.

[0039] In known gas-phase polymerization processes, in addition to gaseous monomers, the reaction mixture also includes an inert polymerization diluent and a chain transfer agent, such as hydrogen, to adjust the molecular weight of the resulting polymer chains. The polymerization diluent is preferably selected from C2 to C8 alkanes, with propane, isobutane, isopentane, and hexane being particularly preferred. Propane is preferably used as the polymerization diluent in the gas-phase polymerization of this disclosure, such that liquid propane is inevitably included in the barrier flow in the upper portion of the feed to the downcomer.

[0040] In one embodiment, the barrier flow includes:

[0041] i. Propylene from 10 mol% to 100 mol%;

[0042] ii. Ethylene from 0 mol% to 80 mol%;

[0043] iii. Propane from 0 mol% to 30 mol%;

[0044] iv. Hydrogen gas from 0 mol% to 5 mol%.

[0045] The composition of the barrier flow indicated above can be obtained by condensing a portion of fresh monomer and propane, said condensate being fed in liquid form to the upper portion of the downcomer. According to an embodiment, a suitable composition of the barrier flow is derived from the condensation and / or distillation of a portion of the gaseous flow continuously recycled to a reactor having two interconnected polymerization zones.

[0046] Additional liquids and / or gases of suitable composition can be fed along the downcomer at a point below the barrier flow.

[0047] The recirculated gas stream typically exits from a gas / solid separator located downstream of the riser, is cooled by an external heat exchanger, and then recirculates to the bottom of the riser. Of course, in addition to gaseous monomers, the recirculated gas stream also includes inert polymerization components (such as propane) and chain transfer agents (such as hydrogen). Furthermore, the composition of the barrier stream derived from the gas recirculation stream through condensation and / or distillation can be appropriately regulated by feeding it before introducing liquid-supplemented monomers and propane into the upper portion of the downcomer.

[0048] The operating parameters of temperature and pressure are those commonly used in gas-phase catalytic polymerization processes. For example, in risers and downcomers, the temperature typically ranges between 60°C and 120°C, while the pressure range can be from 5 bar to 40 bar.

[0049] The process for preparing the propylene-ethylene copolymer of this disclosure is carried out in the presence of a highly stereooriented heterogeneous Ziegler-Natta catalyst. The Ziegler-Natta catalyst suitable for preparing the propylene-ethylene copolymer of this disclosure comprises a solid catalyst component including at least one titanium compound having at least one titanium-halogen bond and at least one electron donor compound (internal donor), both supported on magnesium chloride. The Ziegler-Natta catalyst system also includes an organoaluminum compound as a necessary cocatalyst and an optional external electron donor compound.

[0050] Suitable catalyst systems are described in European patents EP45977, EP361494, EP728769, EP 1272533 and international patent application WO00163261.

[0051] The organoaluminum compound is preferably an alkyl-Al selected from trialkylaluminum compounds, such as, for example, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum. Mixtures of trialkylaluminum with alkylaluminum halides, alkylaluminum hydrides, or alkylaluminum sesquichlorides (such as AlEt2Cl and Al2Et3Cl3) can also be used.

[0052] Preferred external electron donor compounds include silicon compounds, ethers, esters (such as ethyl 4-ethoxybenzoate), amines, heterocyclic compounds, and particularly 2,2,6,6-tetramethylpiperidine, ketones, and 1,3-diethers. Another class of preferred external donor compounds is of formula R. a 5 R b 6 Si(OR 7 ) c A silicon compound, where a and b are integers from 0 to 2, c is an integer from 1 to 3, and the sum of (a+b+c) is 4; R 5 R 6 and R 7 It is an alkyl, cycloalkyl, or aryl group having 1 to 18 carbon atoms, optionally containing heteroatoms. Particularly preferred are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, methyl-tert-butyldimethoxysilane, dicyclopentyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, and 1,1,1,trifluoropropyl-2-ethylpiperidinyl-dimethoxysilane and 1,1,1,trifluoropropyl-methyl-dimethoxysilane. The amount of the external electron donor compound is such that the molar ratio between the organoaluminum compound and the electron donor compound is from 0.1 to 500, preferably from 1 to 100, and more preferably from 2 to 50.

[0053] Unbound by theory, it is believed that the distribution of ethylene in the xylene-soluble and insoluble fractions at 25°C leads to the production of polymers with specific crystallinity through specific polymerization processes used to obtain propylene-ethylene copolymers.

[0054] The propylene-ethylene copolymer disclosed herein can be added together with additives known in the art.

[0055] The propylene-ethylene copolymer of this disclosure exhibits a Shore hardness D of less than 50, preferably less than 47; preferably, the Shore hardness D is greater than 10. The elongation at break (ISO 527-3, technically equivalent to ASTM D638) is preferably greater than 250%, preferably greater than 450%, and preferably less than 1000%. The tensile strength at break, transverse (ISO 527-3), is preferably greater than 21 MPa, preferably greater than 22 MPa, and preferably less than 200 MPa. Furthermore, the propylene-ethylene copolymer of this disclosure exhibits a maximum puncture force preferably greater than 280 N, preferably greater than 320 N, and preferably less than 1000 N, and a longitudinal tear resistance greater than 100 N, preferably greater than 125 N, and preferably less than 1000 N. A balance is achieved between good weldability and improved flexibility, flowability, puncture resistance, and tear resistance.

[0056] The propylene-ethylene copolymer disclosed herein is particularly suitable for roofing applications, especially single-layer roofing coverings, wherein the material’s flexibility, elasticity and ductility, as well as its tear resistance, puncture resistance and weldability, are required in field operations under installation and service conditions; the resulting membrane is subjected to tensile end-tight stress.

[0057] Another object of this disclosure is articles comprising the aforementioned propylene-ethylene copolymers. In particular and preferably, it also relates to blown or cast films or sheets suitable for use in roofing and geomembrane applications.

[0058] Conventional additives commonly used in the prior art can be added to the highly filled flexible polyolefin composition of the present invention.

[0059] The following examples are given to illustrate, but not to limit, this disclosure.

[0060] Example

[0061] Xylene-soluble (XS) fraction at 25°C

[0062] The xylene soluble content at 25°C was determined according to ISO 16 152; the solution volume was 250 ml, and the solution was precipitated at 25°C for 20 minutes, of which 10 minutes were stirred (using a magnetic stirrer), and then dried at 70°C.

[0063] DSC method for melting point

[0064] According to ISO 11357-3, the melting point of samples weighing between 5 mg and 7 mg was measured under cooling and heating conditions in an inert N2 flow at a scan rate of 20°C / min. Indium was used for instrument calibration.

[0065] Melt flow rate (MFR)

[0066] Unless otherwise specified, measurements shall be taken at 230°C and a load of 2.16 kg in accordance with ISO 1133-1:2012.

[0067] Intrinsic viscosity (IV)

[0068] The sample was dissolved in tetrahydronaphthalene at 135°C and then poured into a capillary viscometer. The viscometer tube (Ubbelohde type) was surrounded by a cylindrical glass jacket; this setup allowed for temperature control using a circulating thermostatic liquid. The downward passage of the meniscus was timed by a photoelectric device.

[0069] The meniscus is activated by a counter with a quartz crystal oscillator as it passes the upper lamp. When it passes the lower lamp, the meniscus stops the counter, and the outflow time is recorded: this is converted to an intrinsic viscosity value using the Huggins equation (Huggins, ML, *Journal of the American Chemical Society*, 1942, 64, 2716), provided that the flow time of the pure solvent is known under the same experimental conditions (same viscometer and same temperature). [η] is determined using a single polymer solution.

[0070] Ethylene content in copolymers

[0071] 13 C10 NMR spectra were obtained on a Bruker AV-600 spectrometer equipped with a cryoprobe, operated at 160.91 MHz in Fourier transform mode at 120 °C.

[0072] Sββ carbon (nomenclature according to "through 13 3. Use of reaction probability model (Monomer Sequence Distribution in Ethylene-Propylene Rubber Measured by C NMR) 13The peak at 29.9 ppm was used as an internal reference. (CJ Carman, R.A. Harrington, and C.E. Wilkes, *Macromolecules*, 1977, 10, 536). The sample was dissolved at 8 wt% in 1,1,2,2-tetrachloroethane-d2 at 120 °C. Each spectrum was acquired using a 90° pulse, and removal was performed with a 15-second delay between pulses and CPD. 1 H- 13 C-coupling. 512 transients were stored in 32K data points using a 9000Hz spectral window.

[0073] The spectral assignment, triplet state distribution, and composition evaluation were performed according to Kakugo (“Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with δ-titanium trichloride-diethyl-aluminum chloride”, M. Kakugo, Y. Naito, K. Mizunuma, and T. Miyatake, *Macromolecules*, 1982, 15, 1150) using the following equations:

[0074] PPP=100Tββ / S PPE=100Tβδ / S EPE=100Tδδ / S

[0075] PEP=100Sββ / S PEE=100Sβδ / S EEE=100(0.25Sγδ+0.5Sδδ) / S

[0076] S=Tββ+Tβδ+Tδδ+Sββ+Sβδ+0.25Sγδ+0.5Sδδ

[0077] The molar percentage of ethylene content is evaluated using the following equation: E%mol = 100 * [PEP + PEE + EEE]. The weight percentage of ethylene content is evaluated using the following equation:

[0078] 100*E%mol*MWE

[0079] E%wt.=E%mol*MWE+P%mol*MWP

[0080] Where P%mol is the molar percentage of propylene content, and MWE and MWP are the molecular weights of ethylene and propylene, respectively.

[0081] According to Carman (CJ Carman, R.A. Harrington, and C.E. Wilkes, *Macromolecules*, 1977; 10, 536), the product of the reaction ratios r1 and r2 is calculated as follows:

[0082]

[0083] The stereoregularity of the propylene sequence is determined by PPP mmT ββ (28.90 to 29.65 ppm) and full T ββ The ratio of (29.80 to 28.37 ppm) is calculated as mm content.

[0084] Preparation of injection molded specimens: Obtain test specimens of 80 x 10 x 4 mm according to method ISO 1873-2:2007.

[0085] Preparation of extruded samples: Polymer in granular form was fed through a hopper into a Leonard extruder (single-screw extruder, 40 mm diameter and 27 L / D length). The polymer was first melted (melt temperature 230 °C), compressed, mixed, and finally metered at a throughput of 10 kg / h using a metering pump (15 cc / rpm). The molten polymer exited a flat die (200 mm width, die lip 0.8 to 0.9 mm) and was immediately cooled by a vertical three-roll calender at a roll temperature of 60 °C. A 1 mm thick extruded sheet was obtained.

[0086] Preparation of the compression template: obtained according to ISO 8986-2:2009.

[0087] Flexural modulus: determined on injection-molded test specimens according to method ISO 178:2019.

[0088] Tensile modulus: determined according to ISO 527-2 and ISO 1873-2 injection molded test specimens.

[0089] Breaking strength and elongation at break: determined on injection-molded test specimens according to method ISO 527.

[0090] Vicat softening temperature: determined on injection-molded specimens according to method ISO 306:2013 (A50).

[0091] Charpy impact test at -40°C: Measured on injection-molded specimens according to ISO 179-1:2010.

[0092] Tensile modulus (MD and TD): determined according to method ISO 527-3:2018 on 1 mm thick extruded sheet. Specimen type 2, crosshead speed: 1 mm / min.

[0093] Tensile strength and elongation at break (MD and TD) of extruded sheets: determined according to method ISO 527-3. Specimen type: 5, crosshead speed: 500 mm / min.

[0094] Tear resistance: determined according to method ASTM D 1004 on 1 mm thick extruded sheet. Crosshead speed: 51 mm / min; V-shaped die-cut specimen.

[0095] Puncture resistance and deformation resistance: determined according to method ASTM D 4833 on 1 mm thick extruded sheet. Punch diameter 8 mm, crosshead speed: 300 mm / min.

[0096] Shore A and D on injection molded, die-cut, and extruded sheets: determined according to method ISO 868 (15 seconds).

[0097] Example 1 and Comparative Example 2

[0098] Preparation of Ziegler-Natta solid catalyst components

[0099] The Ziegler-Natta catalyst was prepared according to Example 5, lines 48 to 55 of European Patent EP728769B1.

[0100] Preparation of catalyst system - pre-contact

[0101] Before introducing it into the polymerization reactor, the above solid catalyst components were contacted with triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (D-donor) under the conditions reported in Table 1.

[0102] Prepolymerization

[0103] Then, the catalyst system was prepolymerized at 20°C by suspending it in liquid propylene for 9 minutes, and then introduced into the polymerization reactor.

[0104] polymerization

[0105] As described in European Patent EP782587, polymerization is carried out in a gas-phase polymerization reactor comprising two interconnected polymerization zones (a riser and a downcomer). Hydrogen is used as a molecular weight regulator. Polymer particles leaving the polymerization step are subjected to steam treatment to remove unreacted monomers and dried under a nitrogen stream.

[0106] The main pre-contact, pre-polymerization, and polymerization conditions, as well as the monomer and hydrogen quantities in the polymerization reactor, are reported in Table 1.

[0107] Table 1

[0108]

[0109] H2 = Hydrogen; C2- = Ethylene, C3- = Propylene

[0110] The characterization of the polymers of Example 1 and Comparative Example 2 is reported in Table 2.

[0111] Table 2

[0112]

[0113]

[0114] Table 2 (continued)

[0115]

[0116]

[0117] Table 3 Welding

[0118]

[0119] AD-Adhesion failure

[0120] BRK - Sheet fracture; SEI - Seam outer edge fracture

[0121] Welding tests were performed on 1 mm thick sheets according to ASTM 6392-8. Example 1 showed better quality in terms of puncture resistance, tear resistance, and other parameters; furthermore, the polymer in Example 1 gave better results in the welding test.

Claims

1. A propylene-ethylene copolymer, comprising: i) Xylene-soluble fraction ranging from 35% to 42% by weight at 25°C; ii) The intrinsic viscosity of the fraction of tetrahydronaphthalene that is soluble in xylene at 25°C, measured at 135°C, ranging from 3.2 dl / g to 3.8 dl / g; iii) Melt flow rate (MFR) measured in accordance with ISO 1133 at 230°C and a load of 2.16 kg, ranging from 0.2 g / 10 min to 10 g / 10 min; iv) through 13 C-NMR measurements were performed on ethylene-derived units ranging from 10.3 wt% to 15.4 wt%. v) By 13 C-NMR measurements were performed on the ethylene-derived units in the fraction that was insoluble in xylene at 25°C, ranging from 6.1 wt% to 9.0 wt%. vi) by 13 The ethylene derived units content in said fraction soluble in xylene at 25°C ranges from 22.2 wt% to 26.5 wt% as measured by C-NMR. vii) the fraction soluble in xylene at 25°C measured ranges from 10.5 to 14.2 mole% of said C 13 NMR sequence PEP, and the fraction soluble in xylene at 25°C measured ranges from 10.5 to 14.2 mole% of said C 13 NMR sequence PEP.

2. The propylene-ethylene copolymer according to claim 1, wherein the melt flow rate (MFR), measured according to ISO 1133 at 230°C and a load of 2.16 kg, ranges from 0.3 g / 10 min to 8.0 g / 10 min.

3. The propylene ethylene copolymer according to claim 1, wherein the 13 C-NMR sequence PEP ranges from 4.8 to 6.0 mol%; and the 13 C-NMR sequence PEP ranges from 10.9 to 13.8 mol%.

4. The propylene-ethylene copolymer according to claim 1, wherein in the propylene-ethylene copolymer, the fraction that is insoluble in xylene at 25°C is measured... 13 The C-NMR sequence PEP range is from 4.8 mol% to 6.0 mol%; and the fractions soluble in xylene at 25°C were measured. 13 The PEP range of the C-NMR sequence is from 11.5 mol% to 13.5 mol%.

5. The propylene-ethylene copolymer according to claim 1, wherein in the propylene-ethylene copolymer, by... 13 The content of the ethylene-derived unit in the fraction that is insoluble in xylene at 25°C, as measured by C-NMR, ranges from 6.3 wt% to 8.3 wt%.

6. The propylene ethylene copolymer according to claim 1, wherein the 13 The C-NMR sequence PEE ranges from 10.3 mol% to 13.0 mol%.

7. The propylene ethylene copolymer according to claim 1, wherein the fraction soluble in xylene at 25°C measured in the propylene ethylene copolymer is 13 the C-NMR sequence EEE is lower than 9.0 mol%.

8. The propylene ethylene copolymer according to claim 1, wherein the 13 The C-NMR sequence EEE ranges from 4.5 mole% to 8.5 mole%.

9. The propylene ethylene copolymer according to claim 1, wherein the 13 The C-NMR sequence PEE ranges from 10.8 mol% to 12.5 mol%.

10. A sheet or film comprising the propylene-ethylene copolymer according to claim 1.

11. The sheet or membrane according to claim 10, wherein the sheet or membrane is used as a geomembrane.

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