Polypropylene composition

Abstract

A polypropylene composition comprising: A) from 70% to 90% by weight of a propylene 1-hexene copolymer containing from 0.5% to 3.5% by weight of 1-hexene derived units, B) from 10% to 30% by weight of a copolymer of propylene and ethylene containing from 26.0% to 40.0% by weight of ethylene derived units.

Description

Technical Field

[0001] This disclosure relates to polypropylene compositions containing 1-hexene-derived units having a wide molecular weight distribution and high melt strength. Background Technology

[0002] It is known in the art that the processability of propylene homopolymers and propylene copolymers in the molten state is primarily influenced by molecular weight (typically expressed as melt flow rate (MFR)) and molecular weight distribution (MWD). Molecular weight distribution can be expressed as the ratio of weight-average molecular weight Mw to number-average molecular weight Mn or as the polydispersity index (PI).

[0003] Propylene polymers with a wide molecular weight distribution or high polydispersity index have lower melt viscosity than polymers with a narrow molecular weight distribution. Therefore, these wide MWD propylene polymers flow more easily in thermoforming, injection molding, blow molding or stretch blow molding, coating, and film conversion.

[0004] However, for certain applications, such as polymer foams, products with different flowability combined with high melt strength are particularly desirable. It is known in the art to prepare said polymers by melt blending propylene polymer fractions with different molecular weights or to prepare reactor blends of said fractions in multi-step polymerization.

[0005] EP 1 899 415 relates to propylene homopolymers or copolymers containing up to 5.0% by weight of α-olefin units having 2 to 8 carbon atoms other than propylene, characterized in that the propylene homopolymer or copolymer has a polydispersity index value greater than 15 and less than 4% by weight of xylene-soluble fraction. However, this document does not describe the polypropylene compositions of this disclosure.

[0006] However, additional polypropylene compositions that exhibit increased melt strength are needed, particularly for foaming applications. Summary of the Invention

[0007] This disclosure provides a polypropylene composition comprising:

[0008] A) 70% to 90% by weight of a propylene-1-hexene copolymer, wherein the propylene-1-hexene copolymer contains... 13 The propylene-1-hexene copolymer contains 0.5 wt% to 3.5 wt% of 1-hexene-derived units as measured by C NMR, and has the following characteristics:

[0009] - Included in xylene soluble fractions at 25°C between 1.5 wt% and 6.5 wt%;

[0010] - Melt flow rate (MFR L, according to ISO 1133, condition L, i.e., 230°C and 2.16 kg load) in the range of 1.0 g / 10 min to 7.0 g / 10 min; and

[0011] The polydispersity index is included between 9.2 and 16.3;

[0012] B) 10% to 30% by weight of a copolymer of propylene and ethylene, wherein the copolymer of propylene and ethylene contains... 13 26.0 wt% to 40.0 wt% ethylene-derived units as measured by CNMR;

[0013] In the polypropylene composition:

[0014] - The xylene soluble fraction at 25°C is in the range of 14.0% by weight to 28.0% by weight;

[0015] - The intrinsic viscosity of the xylene soluble fraction at 25°C is in the range of 4.0 dl / g to 6.5 dl / g;

[0016] - The xylene soluble fraction at 25°C passing through 13 The content of ethylene-derived units measured by C NMR was lower than that of ethylene-derived units in component B, and in the range of 19.2 wt% to 37.3 wt%.

[0017] - Melt flow rate (MFR L, according to ISO 1133, condition L, i.e., 230°C and 2.16 kg load) is in the range of 0.5 to 5.0 g / 10 min, and

[0018] The sum of components A and B is 100. Detailed Implementation

[0019] This disclosure provides a polypropylene composition comprising:

[0020] A) 70% to 90% by weight, preferably 74% to 86% by weight, more preferably 77% to 82% by weight of a propylene-1-hexene copolymer, wherein the propylene-1-hexene copolymer contains... 13 The propylene-1-hexene copolymer contains 0.5% to 3.5% by weight, preferably 1.0% to 2.9% by weight, and more preferably 1.2% to 2.4% by weight of 1-hexene-derived units as measured by C NMR, and has the following characteristics:

[0021] - Included in between 1.5 wt% and 6.5 wt%, preferably between 1.8 wt% and 5.5 wt%, more preferably between 2.1 wt% and 5.0 wt% of xylene soluble fraction at 25°C;

[0022] - Melt flow rate (MFR L, according to ISO 1133, condition L, i.e., 230°C and 2.16 kg load) in the range of 1.0 g / 10 min to 7.0 g / 10 min, preferably in the range of 1.50 g / 10 min to 6.5 g / 10 min; and

[0023] - The polydispersity index (PI) is included between 9.2 and 16.3, preferably between 10.1 and 14.4, and more preferably between 10.7 and 13.2.

[0024] B) 10% to 30% by weight, preferably 14% to 26% by weight, more preferably 18% to 23% by weight of a copolymer of propylene and ethylene, wherein the copolymer of propylene and ethylene contains 20.0% to 40.0% by weight, preferably 24.0% to 38.0% by weight, more preferably 28.0% to 36.0% by weight of [a specific ingredient / component]. 13 Ethylene-derived unit measured by C NMR;

[0025] In the polypropylene composition:

[0026] - The xylene soluble fraction at 25°C is in the range of 10.0% to 25.0% by weight; preferably in the range of 16.0% to 22.0% by weight.

[0027] - The intrinsic viscosity of the xylene soluble fraction at 25°C is in the range of 4.0 dl / g to 6.5 dl / g; preferably in the range of 4.5 dl / g to 6.0 dl / g; more preferably in the range of 5.0 dl / g to 5.8 dl / g;

[0028] and

[0029] - The xylene soluble fraction at 25°C passing through 13 The content of ethylene-derived units measured by C NMR is lower than that of ethylene-derived units in component B), and is in the range of 19.2 wt% to 37.3 wt%, preferably 22.5 wt% to 35.3 wt%, more preferably 24.7 wt% to 32.4 wt%.

[0030] - The melt flow rate (MFR L, according to ISO 1133, condition L, i.e. 230°C and 2.16 kg load) is in the range of 0.5 g / 10 min to 5.0 g / 10 min, preferably 0.8 g / 10 min to 4.0 g / 10 min, more preferably 1.0 g / 10 min to 2.0 g / 10 min;

[0031] The sum of components A and B is 100.

[0032] For the purposes of this disclosure, the term copolymer must be intended to be a polymer containing only two monomers (such as propylene and ethylene or propylene and 1-hexene).

[0033] Optionally, the copolymer component B of propylene and ethylene may contain up to 0.6% by weight of 1-hexene-derived units.

[0034] The compositions disclosed herein have high melt strength, and therefore the polypropylene compositions disclosed herein are easily processed and have good flow properties in the molten state, while maintaining good mechanical properties, particularly high rigidity, high yield stress, high creep resistance and high heat distortion resistance.

[0035] Melt strength is a measure of the linear force required to break a polymer melt.

[0036] The compositions disclosed herein have a very broad molecular weight distribution (Mw / Mn). Due to this broad molecular weight distribution, the processability of the polypropylene compositions disclosed herein is significantly improved.

[0037] Preferably, the compositions disclosed herein are characterized by having one or more of the following properties:

[0038] The flexural modulus is included between 500 MPa and 1500 MPa, preferably between 700 MPa and 1200 MPa, as measured according to ISO 178 e ISO 1873-2.

[0039] The Charpy impact strength, measured at 23°C according to ISO 179-1eA and ISO 1873-2, is above 55.0 kJ / m. 2 Preferably higher than 60 kJ / m 2 More preferably higher than 73.0 kJ / m 2 The highest value is 120 kJ / m 2 ;

[0040] The Charpy impact strength, measured at 0°C according to ISO 179-1eA and ISO 1873-2, is higher than 5.0 kJ / m. 2Preferably higher than 6.0 kJ / m 2 More preferably higher than 8.0 kJ / m 2 The highest value was 20.0 kJ / m³. 2 ;

[0041] The Charpy impact, measured at -20°C according to ISO 179-1eA and ISO 1873-2, is higher than 4.0 kJ / m. 2 Preferably higher than 5.0 kJ / m 2 More preferably higher than 5.5 kJ / m 2 The highest value was 15.0 kJ / m³. 2 ;

[0042] The elongation at break, as measured according to ISO 527-2 and ISO 1873-2, is greater than 100%, preferably greater than 180%, more preferably greater than 400%; a higher value is 1000%.

[0043] The melting temperature, as measured by ISO 11357-3, is in the range of 140°C to 160°C, preferably 142°C to 155°C.

[0044] The polypropylene compositions disclosed herein are produced by sequential polymerization in at least two stages, wherein each subsequent polymerization stage is carried out in the presence of a polymeric material formed in the preceding polymerization reaction, wherein component (A) is typically prepared in at least one first polymerization stage and component (B) is typically prepared in at least one second polymerization stage.

[0045] Component A) is prepared in a polymerization method carried out in at least two interconnected polymerization zones. This polymerization method is described in European Patent EP 782587 and International Patent Application WO00 / 02929. The method is carried out in interconnected first and second polymerization zones, with propylene and ethylene or propylene and α-olefins fed into and from the first and second polymerization zones in the presence of a catalyst system. The produced polymer is discharged from both the first and second polymerization zones. The grown polymer particles flow through the first polymerization zone (riser) under rapid fluidization conditions, exit the first polymerization zone and enter the second polymerization zone (downcomer), flow through the second polymerization zone in a densified form under gravity, exit the second polymerization zone and are reintroduced into the first polymerization zone, thereby establishing a polymer cycle between the two polymerization zones. Typically, the rapid fluidization conditions in the first polymerization zone are established by feeding a monomer gas mixture below the point where the grown polymer is reintroduced into the first polymerization zone. The conveying gas enters the first polymerization zone at a rate higher than the conveying rate under operating conditions, and is typically between 2 m / s and 15 m / s. In the second polymerization zone, where the polymer flows in a densified form under gravity, a high solids density value close to the polymer's bulk density is achieved; thus, a positive pressure gain can be obtained along the flow direction, allowing the polymer to be reintroduced into the first reaction zone without mechanical assistance. In this way, a "loop" circulation is established, defined by the pressure balance between the two polymerization zones and the head loss introduced into the system. Optionally, one or more inert gases (such as nitrogen or aliphatic hydrocarbons) are maintained in the polymerization zones in amounts such that the sum of the partial pressures of the inert gases preferably lies between 5% and 80% of the total gas pressure. Operating parameters (such as, for example, temperature) are those commonly used in gas-phase olefin polymerization methods, for example, between 50°C and 120°C, preferably between 70°C and 90°C. The method can be carried out at operating pressures between 0.5 MPa and 10 MPa, preferably between 1.5 MPa and 6 MPa.

[0046] Preferably, the various catalyst components are fed into the first polymerization zone at any point. However, they can also be fed into the second polymerization zone at any point.

[0047] In the polymerization method, a device is provided that can completely or partially prevent gas and / or liquid mixtures present in the riser from entering the downcomer, and introduce gas and / or liquid mixtures with compositions different from those present in the riser into the downcomer. According to a preferred embodiment, introducing the gas and / or liquid mixture having a different composition from the gas mixture present in the riser into the downcomer via one or more inlet lines effectively prevents the latter mixture from entering the downcomer. The gas and / or liquid mixtures of different compositions to be fed into the downcomer can optionally be fed in a partially or completely liquefied form. The molecular weight distribution and thus the PI value of the grown polymer can be conveniently adjusted by carrying out the polymerization method in a reactor illustrated in Figure 4 of International Patent Application WO00 / 02929 and by independently metering comonomers and conventional molecular weight regulators (especially hydrogen) in different proportions into at least one polymerization zone, preferably metered into the riser.

[0048] In the second stage, component B is prepared. The propylene / ethylene copolymer (B) is preferably produced in a conventional fluidized bed gas-phase reactor in the presence of the polymerizing materials and catalyst system from the aforementioned polymerization step.

[0049] Each polymerization stage is carried out in the presence of a highly stereoselective, multiphase Ziegler-Natta catalyst. The Ziegler-Natta catalyst suitable for preparing the propylene polymer compositions of the present invention comprises a solid catalyst component containing 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 polypropylene compositions disclosed herein are preferably obtainable by polymerizing propylene and ethylene at different stages in the presence of a catalyst system comprising products obtained by contacting the following components:

[0052] a) A solid catalyst component comprising magnesium halide, a titanium compound having at least one Ti-halogen bond, and at least one electron donor compound selected from succinates.

[0053] b) Aluminum hydrocarbon compounds

[0054] c) Optionally, an external electron donor compound.

[0055] In the solid catalyst component (a), the succinate is preferably selected from the succinate of formula (I).

[0056]

[0057] (I)

[0058] Where groups R1 and R2 are the same or different from each other, and are C1-C 20 Straight-chain or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkylaryl groups, optionally containing heteroatoms; and groups R3 and R4 may be the same or different from each other, and are C1-C2. 20 Alkyl, C3-C 20 cycloalkyl, C5-C 20 The compound is an aryl, aralkyl, or alkylaryl compound, provided that at least one of them is a branched alkyl group; the two asymmetric carbon atoms identified in the structure of formula (I) are (S, R) or (R, S) type stereoisomers.

[0059] R1 and R2 are preferably C1-C8 alkyl, cycloalkyl, aryl, aralkyl, and alkylaryl. Particularly preferred are compounds in which R1 and R2 are selected from primary alkyl groups, especially branched primary alkyl groups. Examples of suitable R1 and R2 groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, and 2-ethylhexyl. Particularly preferred are ethyl, isobutyl, and neopentyl.

[0060] Particularly preferred are compounds in which the R3 and / or R4 radicals are secondary alkyl groups such as isopropyl, sec-butyl, 2-pentyl, 3-pentyl, or cycloalkyl groups such as cyclohexyl, cyclopentyl, cyclohexylmethyl.

[0061] Examples of the above compounds are pure (S,R) forms or mixtures thereof, optionally in racemic form, of diethyl 2,3-bis(trimethylsilyl)succinate, diethyl 2,3-bis(2-ethylbutyl)succinate, diethyl 2,3-dibenzylsuccinate, diethyl 2,3-dibenzylsuccinate, diisopropylsuccinate, diethyl 2,3-bis(cyclohexylmethyl)succinate, diethyl 2,3-diisobutylsuccinate, diethyl 2,3-dineopentylsuccinate, diethyl 2,3-dicyclopentylsuccinate, and diethyl 2,3-dicyclohexylsuccinate.

[0062] As described above, catalyst component (a) further includes a titanium compound having at least one Ti-halogen bond and magnesium halide. Magnesium halide is preferably in the active form of MgCl2, which is widely known from patent literature as a support for Ziegler-Natta catalysts. Patents USP 4,298,718 and USP 4,495,338 first describe the use of these compounds in Ziegler-Natta catalysis. It is known from these patents that the active form of magnesium dihalide used as a support or co-support in the components of catalysts for olefin polymerization is characterized by an X-ray spectrum in which the intensity of the strongest diffraction line appearing in the spectrum of the inactive halide decreases and is replaced by a halogen whose maximum intensity is shifted at a lower angle relative to a stronger linear direction.

[0063] Preferred titanium compounds used in the catalyst composition of this invention are TiCl4 and TiCl3; in addition, Ti(OR) can also be used. n-y X y The trihalools, where n is the valence of titanium, y is a number between 1 and n-1, X is a halogen, and R is a hydrocarbon group having 1 to 10 carbon atoms.

[0064] Preferably, the catalyst component (a) has an average particle size of 15 to 80 μm, more preferably 20 to 70 μm, and even more preferably 25 to 65 μm.

[0065] The alkyl-Al compound (b) is preferably selected from trialkylaluminum compounds, such as triethylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum. Mixtures of trialkylaluminum with alkylaluminum halides, alkylaluminum hydrides, or alkylaluminum sesquichlorides (such as AlEt2Cl and Al2Et3Cl3) may also be used.

[0066] 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, wherein 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 7The external electron donor compound is optionally an alkyl, cycloalkyl, or aryl group having 1-18 carbon atoms and 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 5 to 500; preferably 5 to 400; more preferably 10 to 200.

[0067] The catalyst forming component can be contacted with a liquid inert hydrocarbon solvent such as propane, n-hexane or n-heptane for about 6 seconds to 60 minutes at a temperature below about 60°C, preferably about 0 to 30°C.

[0068] The catalyst components (a), (b), and optionally (c) described above can be fed into the pre-contact vessel in amounts such that the weight ratio (b) / (a) is in the range of 0.1-10, and if compound (c) is present, the weight ratio (b) / (c) is a weight ratio corresponding to the molar ratio as defined above. Preferably, the components are pre-contacted at a temperature of 10 to 20°C for 1 to 30 minutes. The pre-contact vessel is typically a stirred tank reactor.

[0069] Preferably, the pre-contacted catalyst is then fed into a prepolymerization reactor where the prepolymerization step takes place. The prepolymerization step can be carried out in a first reactor selected from a circulating reactor or a continuous stirred tank reactor, and is typically carried out in the liquid phase. The liquid medium comprises liquid α-olefin monomers, optionally with the addition of an inert hydrocarbon solvent. The hydrocarbon solvent can be aromatic, such as toluene, or aliphatic, such as propane, hexane, heptane, isobutane, cyclohexane, and 2,2,4-trimethylpentane. If present, the amount of hydrocarbon solvent is less than 40% by weight relative to the total amount of α-olefins, preferably less than 20% by weight. Preferably, step (a) is carried out in the absence of an inert hydrocarbon solvent.

[0070] The average residence time in the reactor is typically 2 to 40 minutes, preferably 10 to 25 minutes. The temperature range is between 10°C and 50°C, preferably between 15°C and 35°C. These conditions allow for a prepolymerization degree in the preferred range of 60 to 800 g / g of solid catalyst component, preferably 150 to 500 g / g of solid catalyst component. Step (a) is further characterized by a low concentration of solids in the slurry, typically in the range of 50 g to 300 g of solids per liter of slurry.

[0071] The polypropylene compositions disclosed herein can be used to manufacture foamed articles, such as laminated and unlaminated sheets, beads, and profiles. Foams with densities ranging from 30 kg / m³ to 700 kg / m³, particularly from 100 kg / m³ to 600 kg / m³, can be obtained from the polypropylene compositions disclosed herein, thus enabling applications in thermal and electrical insulation, noise and vibration damping, shock absorption, and weight reduction.

[0072] Specifically, they can be used in the automotive industry for bumper interiors and impact panels, in the marine industry as floating devices, or in cable insulation. The polypropylene compositions disclosed herein can be manufactured into foamed articles using conventional methods. They can be extruded in the presence of at least one foaming agent in a conventional single-screw or twin-screw extruder in single-layer and multi-layer configurations.

[0073] The foaming agent can be a physical foaming agent (such as CO2, gaseous hydrocarbons, H2O, CFCs, or mixtures thereof) or a chemical foaming agent (such as inorganic carbonates, citric acid, or mixtures thereof). Alternatively, the polypropylene compositions of this disclosure can be first granulated and foamed, and then molded according to methods well known in the art to produce foamed polypropylene beads. The polypropylene compositions of this disclosure can be used to manufacture foamed articles, such as foam-coated or uncoated tubes and foam packaging for food.

[0074] The following examples are given for illustrative purposes and not for limiting the invention.

[0075] Example

[0076] Data for propylene polymer materials were obtained using the following methods:

[0077] melt flow rate

[0078] Measured according to ISO 1133 (230°C, 2.16 kg).

[0079] Polydispersion Index (PI)

[0080] According to ISO 6721-10, a few grams of molten homopolymer were dynamically tested using a parallel plate rheometer in a rate scan at 200°C. G' (storage modulus) and G'' (loss modulus) were measured as a function of frequency. Based on the rate scan data, PI was defined by PI = 10⁵ / Gc, where Gc is the cross modulus as the modulus value at G' = G''.

[0081] 1-Hexene content (C6 content)

[0082] The content of 1-hexene was determined by NMR.

[0083] 1313C NMR spectra were acquired on an AV-600 spectrometer equipped with a cryoprobe, operated at 120 °C in Fourier transform mode at 150.91 MHz. The CH peak of propylene was used as an internal reference at 28.83. 13C NMR spectra were acquired using the following parameters:

[0084]

[0085] The total amount of 1-hexene as a molar percentage was calculated from the identified binary group present in the measured NMR using the following relationship:

[0086] [P] = PP + 0.5PH

[0087] [H] = HH + 0.5PH

[0088] propylene / 1-hexene copolymer 13 The assignment of C NMR spectra is calculated according to the table below:

[0089]

[0090] Ethylene (C2) content determined by NMR

[0091] propylene / ethylene copolymer 13 C NMR

[0092] 13 C10 NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with a cryoprobe, operated at 120 °C in Fourier transform mode at 160.91 MHz. Measurements were performed based on the total composition. The ethylene content of component B) was calculated using the amounts of component B) and component A) according to the following equation:

[0093] C 2tot = C 2B x weight % component B / 100.

[0094] The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at 120°C at a concentration of 8 wt% / volume. Each spectrum was acquired with a 90° pulse, with a 15-second delay between pulses, and CPD was used to remove [residue]. 1 H- 13 C-coupling. 512 transient data points were stored in 32K data points using a 9000 Hz spectral window.

[0095] Calculate the distribution of the two-unit group based on the following relationship:

[0096] PP = 100 I1 /

[0097] pH = 100 I2 /

[0098] HH = 100 I3 /

[0099] PE = 100 I4 /

[0100] HE = 100 I6 /

[0101] EE = 100 (0.5( I 13 + I 16 +0.25 I 12 ) /

[0102] in = I1 + I2 + I3 + I4 + I6 + 0.5 (I 13 + I 16 +0.25 I 12

[0103] The total amount of 1-hexene and ethylene as molar percentages is calculated from the binary unit group using the following relationship:

[0104] [P] = PP + 0.5PH + 0.5PE

[0105] [H] = HH + 0.5PH + 0.5HE

[0106] [E] = EE + 0.5PE + 0.5HE

[0107] propylene, 1-hexene, ethylene 13 Allocation of C NMR spectra

[0108]

[0109]

[0110] The molar percentage of ethylene content is evaluated using the following equation:

[0111] E% mol = 100 * [PEP + PEE + EEE]. The weight percentage of ethylene content is evaluated using the following equation:

[0112]

[0113] Where P mol% is the molar percentage of propylene content, and MW E and MW P These are the molecular weights of ethylene and propylene, respectively.

[0114] molar ratio of feed gas

[0115] Determined by gas chromatography.

[0116] Samples for mechanical analysis

[0117] Samples were obtained according to ISO 1873-2.

[0118] Flexural modulus

[0119] Measured according to ISO 178.

[0120] melt strength

[0121] According to ISO 16790, melt strength is a measure of the tensile and breaking properties of plastics by measuring the force (in Newtons) generated when a molten filament is deformed under defined extrusion temperatures and stretching conditions.

[0122] Melting temperature, enthalpy of fusion and crystallization temperature

[0123] According to ISO 11357-3, the determination is performed on samples of 5 to 7 mg weight under an inert N2 flow at a scan rate of 20 °C / min, with both cooling and heating. Indium is used for instrument calibration.

[0124] Xylene soluble and insoluble fractions at 25℃ (room temperature)

[0125] Determination of xylene solubles according to ISO 16 152

[0126] Intrinsic viscosity (IV)

[0127] The sample was dissolved in tetrahydronaphthalene at 135°C and then poured into a capillary viscometer.

[0128] The viscometer tube (Ubbelohde type) is surrounded by a cylindrical glass jacket; this setup allows for temperature control using a circulating thermostatic liquid.

[0129] The downward passage of the meniscus is timed by a photoelectric device. When the meniscus passes in front of the upper lamp, it activates a counter with a quartz crystal oscillator. Upon passing the lower lamp, the meniscus stops the counter and records the outflow time, which is then converted to an intrinsic viscosity value using the following method.

[0130] IZOD impact strength

[0131] Determined according to ISO 180 / 1A

[0132] Charpy impact strength

[0133] According to ISO 179-1eA, e is measured according to ISO 1873-2.

[0134] According to Embodiment 1 of the present invention

[0135] Preparation of solid catalyst components

[0136] According to Example 5 of European Patent EP728769, lines 48 to 55, a Ziegler-Natta catalyst was prepared. Triethylaluminum (TEAL) was used as a co-catalyst and dicyclopentyldimethoxysilane was used as an external donor.

[0137] polymerization

[0138] The polymerization operation is carried out continuously in a series of two-reactor units, each equipped with a device for transferring the product from one reactor to an adjacent reactor. The first reactor is a polymerization apparatus as described in WO00 / 02929.

[0139] The catalyst is fed into a polymerization apparatus comprising two interconnected cylindrical reactors (a riser and a downcomer). Rapid fluidization conditions are established in the riser by recirculating gas from the gas-solid separator, activating the "barrier" effect. The resulting product is then fed into a fluidized bed gas-phase reactor. Hydrogen is used as a molecular weight modifier.

[0140] Component (A) is prepared in the first reactor, while component (B) is prepared in the second reactor.

[0141] Hydrogen is used as a molecular weight regulator.

[0142] The gas phase (propylene, ethylene, 1-butene and hydrogen) was continuously analyzed by gas chromatography.

[0143] At the end of the operation, the powder is discharged and dried under a nitrogen stream.

[0144] The main polymerization conditions are reported in Table 1.

[0145] Table 1

[0146]

[0147] C2 - = Ethylene, C3 - = Propylene, C3 - 1-Hexene

[0148] Polymer characteristics are reported in Table 2.

[0149] Table 2

[0150]

[0151] Comparative Example 2 is Example 1 of WO 2022 / 002514

[0152] The compositions of Example 1 and Comparative Example 2 were blended with a standard additive package.

[0153] Foaming

[0154] The foil was produced using a PM cooling roller foil production line, which features an extruder configuration of Ø 30 mm, L / D 25:1, and a flat die with a width of 350 mm and a gap opening of 1 mm. The chemical blowing agent (CBA) used was 2% loaded HYDROCEROL® CT 660 from Clariant. A bell-shaped temperature distribution was used to produce the foil, with adjustments made individually for each sample.

[0155] Foaming test

[0156] The foaming test was conducted on a KMB tandem extrusion line equipped with a circular die Ø=40 mm, a cooling mandrel Ø=140 mm, a control cabinet, and a traction unit. Talc powder (1% by weight) was used to nucleate the melt, and isobutane was used as the physical foaming agent.

[0157] The results of the foaming test are reported in Table 3.

[0158] Table 3

[0159]

[0160] ++ Good

[0161] + Enough

[0162] - Difference

[0163] The polymer in Example 1 showed improved density, impact appearance, and impact properties.

Claims

1. A polypropylene composition, said polypropylene composition comprising: A) 70% to 90% by weight of a propylene-1-hexene copolymer, said propylene-1-hexene copolymer containing, through 13 The propylene-1-hexene copolymer contains 0.5 wt% to 3.5 wt% of 1-hexene-derived units as measured by C NMR, and has the following characteristics: - Included in xylene soluble fractions at 25°C between 1.5 wt% and 6.5 wt%; - Melt flow rate in the range of 1.0 g / 10 min to 7.0 g / 10 min (MFR L ISO 1133, condition L, i.e., 230 °C and 2.16 kg load); and - The polydispersity index included between 9.2 and 16.3; B) 10% to 30% by weight of a copolymer of propylene and ethylene, wherein the copolymer of propylene and ethylene contains... 13 26.0 wt% to 40.0 wt% ethylene-derived units as measured by CNMR; In the polypropylene composition: - The xylene soluble fraction at 25°C is in the range of 14.0% by weight to 28.0% by weight; - The intrinsic viscosity of the xylene soluble fraction at 25°C is in the range of 4.0 dl / g to 6.5 dl / g; pass 13 The content of ethylene-derived units in the xylene-soluble fraction at 25°C, as measured by C NMR, was lower than that in component B, and in the range of 19.2% to 37.3% by weight. - Melt flow rate (MFR L, according to ISO 1133, condition L, i.e., 230°C and 2.16 kg load) is in the range of 0.5 to 5.0 g / 10 min, and The sum of components A and B is 100.

2. The polypropylene composition according to claim 1, wherein component (A) is in the range of 74% to 86% by weight, and component (B) is in the range of 14% to 26% by weight.

3. The polypropylene composition according to claim 1 or claim 2, wherein in component A), the propylene-1-hexene copolymer accounts for 1.0% to 2.9% by weight.

4. The polypropylene composition according to any one of claims 1 to 3, wherein component A) has a polydispersity index (PI) included between 10.1 and 14.

4.

5. The polypropylene composition according to any one of claims 1 to 4, wherein component A) has a xylene-soluble fraction at 25°C included in amounts between 1.8 wt% and 5.5 wt%.

6. The polypropylene composition according to any one of claims 1 to 5, wherein the copolymer of propylene and ethylene of component B) contains 24.0% by weight to 38.0% by weight of ethylene-derived units.

7. The polypropylene composition according to any one of claims 1 to 6, wherein the xylene-soluble fraction at 25°C is in the range of 16.0% by weight to 22.0% by weight.

8. The polypropylene composition according to any one of claims 1 to 7, wherein the intrinsic viscosity of the xylene-soluble fraction at 25°C is in the range of 4.5 dl / g to 6.0 dl / g.

9. The polypropylene composition according to any one of claims 1 to 8, wherein the content of ethylene-derived units in the xylene-soluble fraction at 25°C is in the range of 22.5% by weight to 35.3% by weight.

10. The polypropylene composition according to any one of claims 1 to 9, wherein the intrinsic viscosity of the xylene-soluble fraction at 25°C is in the range of 5.0 dl / g to 5.8 dl / g.

11. The polypropylene composition according to any one of claims 1 to 10, wherein the content of ethylene-derived units in the xylene-soluble fraction at 25°C is in the range of 24.7% by weight to 32.4% by weight.

12. The polypropylene composition according to any one of claims 1 to 11, wherein the melt flow rate (MFRL, according to ISO 1133, condition L, i.e. 230°C and 2.16 kg load) is in the range of 0.8 g / 10 min to 4.0 g / 10 min.

13. The polypropylene composition according to any one of claims 1 to 2, wherein the intrinsic viscosity of the xylene-soluble fraction at 25°C is in the range of 5.0 dl / g to 5.8 dl / g.

14. The polypropylene composition according to any one of claims 1 to 13, wherein the copolymer of propylene and ethylene of component B) contains 28.0% by weight to 36.0% by weight of ethylene-derived units.

15. A foamed article comprising the polypropylene composition according to claims 1 to 14.

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