High-flow polypropylene compositions for injection molding applications

Abstract

This invention relates to a polypropylene composition having a melt flow rate (MFR2) of 75-250 g / 10 min, comprising a multiphase propylene copolymer and a particulate inorganic nucleating agent, which is particularly suitable for injection molding applications. The invention also relates to a method for producing the polypropylene composition, articles comprising the polypropylene composition, and the use of the polypropylene composition for injection-molded articles.

Description

Technical Field

[0001] This invention relates to a polypropylene composition having a melt flow rate (MFR2) of 75-250 g / 10 min, particularly suitable for injection molding applications, comprising a multiphase propylene copolymer and a particulate inorganic nucleating agent. Background Technology

[0002] Multiphase propylene copolymers are widely used in the automotive industry due to their excellent combination of stiffness and impact resistance. The automotive industry currently has two development trends:

[0003] - To reduce weight, a thin-walled structure is required, and the amount of mineral reinforcement material needs to be kept low.

[0004] -Using post-industrial or even post-consumer recycled materials with low MFR and limited impact strength necessitates the addition of other components to the final composition.

[0005] To meet these requirements, compositions suitable for automotive applications need to have high fluidity (manifested as high melt flow rate), high toughness after processing (manifested as low initial linear coefficient of thermal expansion (CLTE)), good impact properties (especially at low temperatures, as indicated by high Charpy notched impact strength and instrument puncture test), and high stiffness (manifested as high tensile modulus).

[0006] The properties of the composition can be tuned by introducing polymeric components adapted to the properties of the elastomeric phase of one or more multiphase polypropylene copolymers (e.g., elastic polymers similar to plasmids), and / or adapted to the properties of the matrix phase of one or more multiphase polypropylene copolymers (e.g., homogeneous or random copolymers of propylene).

[0007] However, more significant effects can be obtained by adjusting the properties of one or more multiphase polypropylene copolymers that are the main components of the composition.

[0008] WO 2017 / 148970 A1 discloses multiphase propylene copolymers containing a multimodal matrix phase, which can exhibit high melt flow rates. However, examples show that high melt flow rates of at least 70 g / 10 min exhibit poor tensile and impact balance properties, especially at low temperatures.

[0009] Therefore, there is a need in the art for novel multiphase polypropylene copolymers suitable as major components in polypropylene compositions for injection molding applications. It has been found that compositions with an excellent balance of properties can be obtained by carefully tuning the properties of multiphase polypropylene copolymers, particularly the properties of the elastomeric phase. These properties include high fluidity (expressed by high melt flow rate) and high post-processing dimensional stability (expressed by low initial linear coefficient of thermal expansion (CLTE)), good impact properties (especially at low temperatures, expressed by high Charpy notched impact strength and instrument puncture test results), and high stiffness (expressed by high tensile modulus). These polypropylene compositions are suitable for injection molding applications, particularly automotive applications. Summary of the Invention

[0010] Invention Abstract

[0011] This invention relates to a polypropylene composition comprising:

[0012] (A) A multiphase propylene copolymer, comprising at least 95.0 wt%, for example 95.0 to 99.9 wt%, preferably 96.0 to 99.5 wt%, more preferably 97.5 to 99.0 wt%; and

[0013] (B) A particulate inorganic nucleating agent, the content of which is at most 1.5 wt%, for example 0.01 to 1.5 wt%, preferably 0.1 to 1.3 wt%, more preferably 0.2 to 1.2 wt%.

[0014] All percentages refer to the total content, and are therefore...

[0015] The multiphase propylene copolymer (A) comprises a matrix phase and an elastomer phase dispersed therein, and the composition has

[0016] (1) Soluble fraction (SF) and crystalline fraction (CF) were determined according to CRYSTEX QC analysis;

[0017] (2) The content of soluble fraction (SF) determined by CRYSTEX QC analysis is in the range of 15.0 wt% to 30.0 wt%, preferably between 17.5 wt% and 27.5 wt%, and more preferably between 20.0 wt% and 25.0 wt%.

[0018] (3) The ethylene content in the soluble fraction C2(SF) was determined by quantitative analysis. 13 The content, determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy, is in the range of 25.0 to 40.0 wt%, preferably in the range of 27.5 to 37.5 wt%, and more preferably in the range of 27.5 to 36.5 wt%.

[0019] (4) The intrinsic viscosity iV (SF) of the soluble fraction, measured in decahydronaphthalene at 135°C according to DIN ISO 1628 / 1, is between 2.0 dl / g and 3.5 dl / g, preferably between 2.3 and 3.0 dl / g, and more preferably between 2.5 and 2.9 dl / g;

[0020] (5) The ratio of ethylene content (C2(SF) / C2(CF)) between the soluble fraction and the crystalline fraction is 11.0 to 15.0, preferably 11.5 to 15.0, more preferably 12.0 to 15.0; and

[0021] (6) The melt flow rate MFR2 (230°C, 2.16 kg, ISO 1133) is 75 to 250 g / 10 min, preferably 80 to 200 g / 10 min, and more preferably 85 to 180 g / 10 min.

[0022] Furthermore, the present invention relates to a method for preparing the above or below polypropylene composition, wherein a multiphase polypropylene copolymer (A) is polymerized in the presence of a Ziegler-Natta catalyst system in a multi-stage process comprising at least two polymerization reactors connected in series, and then the multiphase polypropylene copolymer (A) is blended with a particulate inorganic nucleating agent (B).

[0023] Furthermore, the present invention relates to an article, preferably a molded article, more preferably an injection-molded article, and even more preferably an injection-molded automotive article comprising the above or the following polypropylene composition.

[0024] Finally, the present invention relates to the use of the polypropylene compositions described above or below in injection-molded articles (preferably automotive articles).

[0025] definition

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While the invention may be practiced and tested using similar or equivalent methods and materials as described herein, preferred methods and materials are described herein. In describing and claiming protection for this invention, the following terms will be used according to the following definitions. Unless explicitly stated otherwise, the use of the words "a," "an," etc., refers to one or more.

[0027] Polymer blends are mixtures of two or more polymer components. Generally, blends can be prepared by mixing two or more polymer components. A suitable mixing procedure known in the art is post-polymerization blending.

[0028] Post-polymerization blending can be a dry blending of polymer components (such as polymer powders and / or composite polymer granules), or it can be a melt blending of polymer components by melt mixing.

[0029] Propylene homopolymer is a polymer primarily composed of propylene monomer units. Due to the presence of impurities, especially during commercial polymerization, propylene homopolymer may contain up to 0.1 mol% of comonomer units, preferably up to 0.05 mol% of comonomer units, and most preferably up to 0.01 mol% of comonomer units.

[0030] Polypropylene is a polymer composed of propylene-derived units, with a propylene content exceeding 50 mol%.

[0031] Polyethylene is a polymer composed of ethylene-derived units, with an ethylene content exceeding 50 mol%.

[0032] The term "elastomer" refers to a natural or synthetic polymer that possesses elastic properties. The term "plastic" refers to a natural or synthetic polymer that combines the properties of an elastomer and a plastic, such as having rubber-like properties and the processability of a plastic. Ethylene-based plastics are plastics composed of ethylene-derived units with an ethylene content exceeding 50% by weight.

[0033] The presence of multiphase properties can be readily determined by the number of glass transition points (e.g., in dynamic mechanical analysis (DMA)) and / or by high-resolution microscopy (e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), or atomic force microscopy (AFM)).

[0034] Like "bimodal" or "trimodal," "multimodal" describes a probability distribution with multiple relative maximum values. Specifically, the term "polymer modality" refers to the form of its molecular weight distribution (MWD) curve, i.e., the appearance of a graph showing the relationship between the polymer's weight fraction and its molecular weight. If the polymer is produced in a sequential process, i.e., using reactors coupled in a series configuration and with different conditions in each reactor, then the different polymer fractions produced in different reactors will each have their own molecular weight distribution, which may differ significantly from each other. The resulting final polymer MWD curve can be viewed as a superposition of the MWD curves of the individual polymer fractions, and therefore will show significant maximum values, or at least be significantly wider than the curves of the individual fractions. Polymers with such MWD curves are referred to as bimodal, trimodal, or multimodal, respectively.

[0035] Polymers polymerized in a single polymerization stage, or polymers polymerized in a sequential process using comparable polymerization conditions in each reactor, typically exhibit a single maximum value in their molecular weight distribution (MWD) curves. Such polymers are considered to be unimodal.

[0036] The term "XCS" refers to the cold soluble fraction of xylene (XCS wt%) determined at 25°C according to ISO 16152. The term "XCI" refers to the cold insoluble fraction of xylene (XCI wt%) determined at 25°C according to ISO 16152.

[0037] Reactor blends are blends produced in two or more reactors coupled in series or in a reactor with two or more reaction chambers. Reactor blends can also be produced by solution blending. Reactor blends are distinctly different from compounds produced by melt extrusion.

[0038] Unless otherwise stated, "%" means weight percentage (wt%). Detailed Implementation

[0039] Composition

[0040] In a first aspect, the present invention relates to a polypropylene composition comprising:

[0041] (A) a multiphase propylene copolymer, comprising at least 95.0 wt%, for example 95.0 to 99.9 wt%, preferably 96.0 to 99.5 wt%, more preferably 97.5 to 99.0 wt%; and

[0042] (B) A particulate inorganic nucleating agent, the content of which is at most 1.5 wt%, for example 0.01 to 1.5 wt%, preferably 0.1 to 1.3 wt%, more preferably 0.2 to 1.2 wt%.

[0043] All percentages refer to total content. The multiphase propylene copolymer (A) includes a matrix phase and an elastomer phase dispersed therein.

[0044] The composition has

[0045] (1) Soluble fraction (SF) and crystalline fraction (CF) determined by CRYSTEX QC analysis;

[0046] (2) Based on CRYSTEX QC analysis, the preferred concentration is within the range of 15.0 wt% to 30.0 wt%, preferably 17.5 wt%.

[0047] The content of soluble fraction (SF) is between 27.5 wt%, more preferably between 20.0 wt% and 25.0 wt%.

[0048] (3) By quantitative 13 The ethylene content of the soluble fraction C2(SF) was determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy, in the range of 25.0 to 40.0 wt%, preferably in the range of 27.5 to 37.5 wt%, and more preferably in the range of 27.5 to 36.5 wt%.

[0049] (4) The intrinsic viscosity of the soluble fraction iV (SF) is measured in decahydronaphthalene at 135°C according to DIN ISO 1628 / 1, between 2.0 dl / g and 3.5 dl / g, preferably 2.3 to 3.0 dl / g, and more preferably 2.5 to 2.9 dl / g.

[0050] (5) The ratio of ethylene content (C2(SF) / C2(CF)) of the soluble fraction and the crystalline fraction is 11.0 to 15.0, preferably 11.5 to 15.0, more preferably 12.0 to 15.0; and

[0051] (6) A melt flow rate MFR2 of 75 to 250 g / 10 min, preferably 80 to 200 g / 10 min, and more preferably 85 to 180 g / 10 min (230 °C, 2.16 kg, ISO 1133).

[0052] The composition according to the invention for automotive applications has one or more of the following characteristics:

[0053] The melt flow rate (MFR2) of the composition (230°C, 2.16 kg, ISO 1133) is 75 to 250 g / 10 min, preferably 80 to 200 g / 10 min, and more preferably 85 to 180 g / 10 min.

[0054] The composition can be characterized by CRYSTEX QC analysis. In CRYSTEX QC analysis, crystalline fractions (CF) and soluble fractions (SF) can be obtained, which can be quantified and analyzed based on the content of monomers and comonomers, as well as intrinsic viscosity (iV). Therefore, the crystalline fraction (CF) represents the crystalline portion of the polypropylene composition, such as the matrix phase of a multiphase propylene copolymer. The soluble fraction (SF) represents the amorphous portion of the polypropylene composition, such as the elastomeric phase of a multiphase propylene copolymer.

[0055] The composition has a soluble fraction (SF) and a crystalline fraction (CF), as determined by CRYSTEX QC analysis.

[0056] In CRYSTEX QC analysis, the composition exhibited more than one of the following properties:

[0057] (1) The content of the crystal fraction (CF) determined by CRYSTEX QC analysis is in the range of 70.0 to 85.0 wt%, preferably in the range of 72.5 to 82.5 wt%, and more preferably in the range of 75.0 to 80.0 wt%.

[0058] (2) The soluble fraction (SF) content, as determined by CRYSTEX QC analysis, is between 15.0 wt% and 30.0 wt%.

[0059] Within the range, preferably from 17.5 wt% to 27.5 wt%, more preferably from 20.0 wt% to 25.0 wt%.

[0060] Within the range.

[0061] The crystalline fraction (CF) has one or more of the following preferred properties:

[0062] (1) Through quantitative analysis 13 The ethylene content (C2(CF)) determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy is in the range of 1.5 to 3.0 wt%, preferably in the range of 1.8 to 2.8 wt%, and more preferably in the range of 2.0 to 2.7 wt%.

[0063] Within the range; and / or

[0064] (2) According to DIN ISO 1628 / 1, the intrinsic viscosity (iV(CF)) of decahydronaphthalene at 135°C is 0.7 to 1.7 dl / g, preferably 0.8 to 1.5 dl / g, and more preferably 0.9 to 1.4 dl / g.

[0065] The soluble fraction (SF) has one or more of the following preferred properties:

[0066] (1) Through quantitative analysis 13 Ethylene content (C2(SF)) determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy.

[0067] Within the range of 25.0 to 40.0 wt%, preferably within the range of 27.5 to 37.5 wt%, more preferably within the range of 27.5 to 36.5 wt%; and / or

[0068] (2) According to DIN ISO 1628 / 1, the intrinsic viscosity (iV(CF)) of decahydronaphthalene measured at 135°C is 2.0.

[0069] The concentration is dl / g to 3.5 dl / g, preferably 2.3 to 3.0 dl / g, and more preferably 2.5 to 2.9 dl / g.

[0070] The polypropylene composition preferably comprises ethylene-derived units in a total amount of 5.5 to 12.5 wt%, more preferably 6.0 to 12.0 wt%, and even more preferably 6.5 to 11.5 wt%, by quantitative analysis. 13 FT-IR spectroscopy determination calibrated by C-NMR spectroscopy.

[0071] The ratio of the intrinsic viscosity of the soluble fraction to the crystalline fraction (iV(SF) / iV(CF)) is preferably in the range of 2.2 to 3.0, more preferably in the range of 2.4 to 2.9, and even more preferably in the range of 2.6 to 2.8.

[0072] The ratio of ethylene content in the soluble fraction to the crystalline fraction (C2(SF) / C2(CF)) is in the range of 11.0 to 15.0, preferably in the range of 11.5 to 15.0, and more preferably in the range of 12.0 to 15.0.

[0073] Preferably, the polymer component in the polypropylene composition consists only of propylene units and ethylene units.

[0074] Although not measured, the sum of the content of propylene-derived (C3) units in the soluble fraction (SF) and the content of ethylene-derived (C2) units in the soluble fraction (SF) is preferably at most 100 wt%.

[0075] The content of propylene (C3)-derived units in the soluble fraction (SF) is preferably in the range of 60.0 to 75.0 wt%, more preferably in the range of 62.5 to 72.5 wt%, and even more preferably in the range of 63.5 to 72.5 wt%.

[0076] Although it cannot be directly measured, the sum of the contents of propylene-derived (C3) units in the crystalline fraction (CF) and ethylene-derived (C2) units in the crystalline fraction (CF) is preferably at most 100 wt%.

[0077] The content of propylene (C3)-derived units in the crystalline fraction (CF) is preferably in the range of 97.0 to 98.5 wt%, more preferably in the range of 97.2 to 98.2 wt%, and even more preferably in the range of 98.0 to 98.3 wt%.

[0078] The total content of units derived from the propylene (C3) polypropylene composition is preferably 87.5 to 94.5 wt%, more preferably 88.0 to 94.0 wt%, and even more preferably 88.5 to 93.5 wt%.

[0079] In particular, the properties of the soluble fraction (SF) preferably result in a specific morphology of the elastomeric phase dispersed within the matrix phase of the multiphase polypropylene copolymer. For example, under microscopic observation, the elastomeric phase can be identified as particles within the matrix phase.

[0080] The elastomeric phase particles dispersed in the matrix phase preferably have a number-average particle size of 1150 to 1325 nm, more preferably 1175 to 1300 nm, and even more preferably 1200 to 1275 nm.

[0081] The melting temperature Tm of the polypropylene composition is preferably between 155 and 175°C, more preferably between 157 and 172°C, and even more preferably between 160 and 170°C.

[0082] Furthermore, the crystallization temperature Tc of the polypropylene composition is preferably between 120 and 140°C, more preferably between 122 and 137°C, and even more preferably between 125 and 135°C.

[0083] Furthermore, the heat distortion temperature (HDT B) of the polypropylene composition is preferably between 92 and 110°C, more preferably between 93 and 108°C, and even more preferably between 95 and 105°C.

[0084] The polypropylene composition according to the invention preferably exhibits an excellent balance of performance in terms of flowability (melt flow rate as described above), impact properties, and especially mechanical properties (such as tensile properties).

[0085] The tensile modulus of the polypropylene composition is preferably from 1250 MPa to 1600 MPa, more preferably from 1300 to 1550 MPa, and even more preferably from 1300 to 1520 MPa.

[0086] Furthermore, the elongation at break of the polypropylene composition is preferably between 4.0% and 25.0%, more preferably between 4.5% and 20.0%, and even more preferably between 4.7% and 17.5%.

[0087] Furthermore, the Charpy notched impact strength (CNIS at 23°C) of the polypropylene composition is preferably between 2.5 and 6.4 kJ / m. 2 More preferably, it is between 2.7 and 6.0 kJ / m 2 between.

[0088] Furthermore, the Charpy notched impact strength (CNIS at -20°C) of the polypropylene composition is preferably between 2.0 and 5.5 kJ / m. 2 More preferably, it is between 2.3 and 5.0 kJ / m 2 between.

[0089] Even more preferably, the composition exhibits good impact strength in instrument puncture tests:

[0090] (1) The puncture energy of the composition measured at 23°C is 4.5 to 20.0 J, preferably 5.0 to 15.0 J.

[0091] (2) The puncture energy of the composition measured at -20°C is 3.5 to 15.0 J, preferably 4.0 to 12.0 J.

[0092] The polypropylene composition contains a multiphase propylene copolymer (A) in a content of at least 95.0 wt%, for example 95.0 to 99.9 wt%, preferably 96.0 to 99.5 wt%, and more preferably 97.5 to 99.0 wt%, based on the total weight of the polypropylene composition.

[0093] The multiphase polypropylene copolymer (A) has one or more of the following preferred properties:

[0094] (1) The melt flow rate MFR2 (230°C, 2.16 kg, ISO 1133) is 75 to 250 g / 10 min, preferably 80 to 200 g / 10 min, more preferably 85 to 180 g / 10 min; and / or

[0095] (2) Through quantitative 13 The total content of ethylene (C2) derived units, determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy, is 5.5 to 12.5 wt%, preferably 6.0 to 12.0 wt%, more preferably 6.5 to 11.5 wt%; and / or

[0096] (3) The melting temperature Tm, determined by differential scanning calorimetry (DSC) according to ISO 11357 / Part 3 / Method C2, is 155 to 175°C, preferably 157 to 172°C, more preferably 160 to 170°C; and / or

[0097] (4) The crystallization temperature Tc, determined by differential scanning calorimetry (DSC) according to ISO 11357 / Part 3 / Method C2, is 120 to 140 °C, preferably 122 to 137 °C, more preferably 125 to 135 °C; and / or

[0098] (5) Determination of xylene cold soluble fraction (XCS) at 25°C according to ISO 16152, first edition, 2005-07-01.

[0099] The content, based on the total weight of the multiphase propylene copolymer (A), is 12.5 to 30.0 wt%, preferably 15.0 to 27.5 wt%, more preferably 17.5 to 25.0 wt%; and / or

[0100] (6) The ethylene content of the XCS fraction (C2(XCS)) is 22.5 to 50.0 wt%, preferably 25.0 to 47.5 wt%, more preferably 27.5 to 45.0 wt%, and is measured quantitatively. 13FT-NMR spectroscopy calibrated by C-NMR spectroscopy

[0101] IR spectroscopy; and / or

[0102] (7) According to DIN ISO 1628 / 1, the intrinsic viscosity iV (XCS) of the XCS fraction in decahydronaphthalene at 135°C is 3.0 to 4.5 dl / g, preferably 3.1 to 4.2 dl / g, and more preferably 3.2 to 4.0 dl / g.

[0103] Furthermore, the polypropylene composition also contains a particulate inorganic nucleating agent (B) in a content of up to 1.5 wt% based on the total weight of the polypropylene composition, for example, 0.01 to 1.5 wt%, preferably 0.1 to 1.3 wt%, and more preferably 0.2 to 1.2 wt%.

[0104] The preferred granular inorganic nucleating agent (B) is talc.

[0105] The median particle size d of the particulate inorganic nucleating agent (B) before mixing 50 The thickness is 0.5 to 7.5 μm, preferably 1.0 to 5.0 μm.

[0106] Furthermore, the top-cut particle size d of the particulate inorganic nucleating agent (B) before mixing 95 The thickness is 2.0 to 20.0 μm, preferably 3.0 to 15.0 μm.

[0107] The composition also includes additives, which are present in a content of up to 3.0 wt% based on the total weight of the composition, preferably in the range of 0.1 to 3.0 wt%, and more preferably in the range of 0.5 to 2.5 wt%.

[0108] Typically, additives can be selected from antioxidants, antislip agents, nucleating agents (different from particulate inorganic nucleating agents (B)), anti-scratch agents, anti-scorching agents, metal passivators, UV stabilizers, acid scavengers, lubricants, antistatic agents, pigments, and combinations thereof. These additives are well-known in the polymer industry, and skilled technicians are familiar with their use. Any existing additive can be added as a separate raw material or as a mixture with the carrier polymer, i.e., added in the so-called masterbatch.

[0109] The polypropylene composition may contain a multiphase polypropylene copolymer (A), a particulate inorganic nucleating agent (B), and other components other than optional additives, such as small amounts of other polymer components, for example, up to 3.0 wt%.

[0110] However, it is preferred that the polypropylene composition consists of a multiphase propylene copolymer (A), a particulate inorganic nucleating agent (B), and optional additives.

[0111] process

[0112] In another aspect, the present invention relates to a method for preparing the above-described or below-described polypropylene composition, wherein a multiphase polypropylene copolymer (A) is polymerized in a multi-stage process in at least two polymer reactors connected in series in the presence of a Ziegler-Natta catalyst system, and the multiphase polypropylene copolymer (A) is blended with a particulate inorganic nucleating agent.

[0113] In a multi-stage process, a propylene homopolymer is prepared in at least one first polymerization step, while in at least one subsequent polymerization step, a propylene-ethylene copolymer is prepared in the presence of the propylene homopolymer or produced by blending the propylene homopolymer with the propylene-ethylene copolymer after polymerization of the propylene homopolymer and the propylene-ethylene copolymer.

[0114] In a particularly preferred embodiment, the propylene homopolymer matrix is ​​produced at least in a slurry reactor, followed by the production of the propylene-ethylene copolymer at least in a gas phase reactor.

[0115] Therefore, multiphase propylene copolymers can typically be prepared in a cascade reactor configuration of at least two reactors, preferably at least three reactors, and more preferably at least four reactors, wherein the first reactor is preferably a ring-shaped liquid bulk reactor, and all subsequent reactors are preferably fluidized bed-shaped gas-phase reactors. The number of subsequent reactors generally does not exceed six, preferably no more than five. Preferably, multiphase propylene copolymers are produced in a cascade of four reactors.

[0116] The preferred multi-stage process is developed by Borealis (referred to as Borealis). The "ring-gas phase" process developed by the technology is described in patent documents such as EP 0 887 379, WO 92 / 12182, WO 2004 / 000899, WO 2004 / 111095, WO99 / 24478, WO 99 / 24479 or WO 00 / 68315.

[0117] Another suitable slurry-gas phase process is Basell's. Process.

[0118] Preferably, the component produced in the first two reactors is a crystallizable propylene homopolymer, while the component produced in the subsequent third and fourth reactors is an amorphous propylene-ethylene copolymer with a high content of ethylene comonomer.

[0119] When propylene homopolymers and / or propylene-ethylene copolymers are polymerized in multiple polymerization reactors, such as in two subsequent polymerization reactors, the preferred polymerization conditions should be adjusted to produce comparable propylene homopolymer fractions and / or propylene-ethylene copolymer fractions.

[0120] Preferably, the propylene homopolymer is unimodal.

[0121] More preferably, the propylene-ethylene copolymer is unimodal.

[0122] In a preferred embodiment, the process includes the following steps:

[0123] a) In the presence of a Ziegler-Natta catalyst system, propylene is polymerized in a first polymerization reactor to obtain a first propylene homopolymer fraction;

[0124] b) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system and the first propylene homopolymer fraction from the first polymerization reactor to the second polymerization reactor;

[0125] c) In the second polymerization reactor, propylene is polymerized in the presence of a Ziegler-Natta catalyst system to obtain a second propylene homopolymer fraction;

[0126] d) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction, and the second propylene homopolymer fraction from the second polymerization reactor to the third polymerization reactor;

[0127] e) In the third polymerization reactor, propylene and ethylene are polymerized in the presence of a Ziegler-Natta catalyst system to obtain a first propylene-ethylene copolymer fraction;

[0128] f) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction, the second propylene homopolymer fraction, and the first propylene-ethylene copolymer fraction from the third polymerization reactor to the fourth polymerization reactor;

[0129] g) In the fourth polymerization reactor, propylene and ethylene are polymerized in the presence of a Ziegler-Natta catalyst system to obtain a second propylene-ethylene copolymer fraction;

[0130] h) Take out a polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction and the second propylene homopolymer fraction, and the first propylene-ethylene copolymer fraction and the second propylene-ethylene copolymer fraction from the fourth polymerization reactor;

[0131] i) Obtain a multiphase propylene copolymer (A) comprising a first propylene homopolymer fraction and a second propylene homopolymer fraction, as well as a first propylene-ethylene copolymer fraction and a second propylene-ethylene copolymer fraction;

[0132] j) Blend the multiphase polypropylene copolymer (A) with a particulate inorganic nucleating agent (B).

[0133] The preferred first polymerization reactor is a slurry reactor, such as a ring reactor.

[0134] The operating temperature in the first polymerization reactor (preferably a ring reactor) is preferably between 62 and 85°C, more preferably between 65 and 82°C, and even more preferably between 67 and 80°C.

[0135] Typically, the pressure in the first polymerization reactor (preferably a ring reactor) is between 20 and 80 bar, preferably 30 to 70 bar, for example 35 to 65 bar.

[0136] The propylene homopolymer is preferably prepared in a first polymerization reactor (preferably a ring reactor). Therefore, the first propylene polymer fraction is preferably a first propylene homopolymer fraction.

[0137] Hydrogen is preferably added to the first polymerization reactor to control the molecular weight, i.e., the melt flow rate MFR2.

[0138] Preferably, in the first polymerization reactor (preferably a ring reactor), the ratio of hydrogen to propylene (H2 / C3) is controlled in the range of 20 to 50 mol / kmol, more preferably in the range of 30 to 40 mol / kmol.

[0139] Due to the high hydrogen content, the melt flow rate of the first propylene polymer fraction is very high.

[0140] Preferably, the melt flow rate MFR2 (230°C, 2.16 kg, ISO 1133) of the first propylene polymer fraction is in the range of 50 to 1000 g / 10 min, more preferably in the range of 150 to 850 g / 10 min, and even more preferably in the range of 300 to 700 g / 10 min.

[0141] The second polymerization reactor is preferably a first gas-phase reactor, such as a first fluidized bed gas-phase reactor.

[0142] Preferably, the operating temperature of the second polymerization reactor (preferably the first gas-phase reactor) is in the range of 75 to 95°C, more preferably in the range of 78 to 92°C.

[0143] Typically, the pressure of the second polymerization reactor (preferably the first gas-phase reactor) is in the range of 5 to 50 bar, preferably in the range of 15 to 40 bar.

[0144] Propylene homopolymer is prepared in a second polymerization reactor (preferably a first gas-phase reactor). Therefore, the second propylene polymer fraction is preferably a second propylene homopolymer fraction.

[0145] Hydrogen is preferably added in the second polymerization reactor to control the molecular weight, i.e. the melt flow rate MFR2.

[0146] The hydrogen to propylene ratio (H2 / C3) in the second polypropylene reactor (preferably the first gas-phase reactor) is preferably in the range of 150 to 500 mol / kmol, more preferably in the range of 200 to 350 mol / kmol.

[0147] Due to the high hydrogen content, the melt flow rates of the first and second propylene polymer fractions are very high.

[0148] Preferably, the melt flow rate MFR2 (230°C, 2.16 kg, ISO 1133) of the combined first and second propylene polymer fractions is in the range of 50 to 1000 g / 10 min, more preferably in the range of 150 to 850 g / 10 min, and more preferably in the range of 300 to 700 g / 10 min.

[0149] The third polymerization reactor is preferably a second gas-phase reactor, such as a second fluidized bed gas-phase reactor.

[0150] Preferably, the operating temperature of the third polymerization reactor (preferably the second gas-phase reactor) is in the range of 65 to 85°C, more preferably in the range of 68 to 82°C. Typically, the operating temperature of the third polymerization reactor is lower than that of the second polymerization reactor.

[0151] Typically, the pressure of the third polymerization reactor (preferably the second gas-phase reactor) is in the range of 5 to 40 bar, preferably in the range of 10 to 30 bar.

[0152] The propylene-ethylene copolymer is prepared in a third polymerization reactor (preferably a second gas-phase reactor). Therefore, the third propylene polymer fraction is the first propylene-ethylene homopolymer fraction.

[0153] In the third polymerization reactor (preferably the second gas-phase reactor), the ratio of ethylene to propylene (C2 / C3 ratio) is controlled in the range of 200 to 500 mol / kmol, more preferably in the range of 250 to 475 mol / kmol.

[0154] Because of the high ethylene to propylene content ratio (C2 / C3 ratio), the third propylene polymer fraction is preferably an elastic block copolymer having both propylene-rich and ethylene-rich portions.

[0155] It is preferable to add hydrogen gas in the third polymerization reactor to control the molecular weight, i.e. the melt flow rate MFR2.

[0156] Preferably, in the third polymerization reactor, the ratio of hydrogen to ethylene (H2 / C2 ratio) is controlled in the range of 20 to 100 mol / kmol, more preferably in the range of 30 to 75 mol / kmol.

[0157] The melt flow rate (MFR2, 230°C, 2.16 kg, ISO 1133) of the first, second and third propylene polymer fractions preferably is in the range of 30 to 500 g / 10 min, more preferably in the range of 65 to 350 g / 10 min, and even more preferably in the range of 75 to 250 g / 10 min.

[0158] The fourth polymerization reactor is preferably a third gas-phase reactor, such as a third fluidized bed gas-phase reactor.

[0159] Preferably, the operating temperature of the fourth polymerization reactor (preferably the third gas-phase reactor) is in the range of 65 to 85°C, more preferably in the range of 68 to 82°C. Typically, the operating temperature of the fourth polymerization reactor is lower than that of the second polymerization reactor.

[0160] Typically, the pressure in the fourth polymerization reactor (preferably the third phase reactor) is in the range of 5 to 40 bar, preferably in the range of 10 to 30 bar.

[0161] The propylene-ethylene copolymer is prepared in a fourth polymerization reactor (preferably a third gas-phase reactor). Therefore, the fourth propylene polymer fraction is the second propylene-ethylene copolymer fraction.

[0162] In the fourth polymerization reactor (preferably the third gas-phase reactor), the ratio of ethylene to propylene (C2 / C3 ratio) is in the range of 150 to 650 mol / kmol, more preferably in the range of 250 to 500 mol / kmol.

[0163] Since the ethylene to propylene content ratio (C2 / C3 ratio) is relatively high, the fourth propylene polymer fraction is preferably an elastic block copolymer of a propylene-rich portion and an ethylene-rich portion.

[0164] Preferably, hydrogen is added to the fourth polymerization reactor to control the molecular weight, i.e., the melt flow rate MFR2.

[0165] Preferably, the hydrogen to propylene ratio (H2 / C3 ratio) in the fourth polypropylene reactor (preferably the third gas-phase reactor) is in the range of 50 to 250 mol / kmol, more preferably in the range of 80 to 175 mol / kmol.

[0166] The melt flow rate (MFR2) (230°C, 2.16 kg, ISO 1133) of the first, second, third and fourth propylene polymer fractions preferably is in the range of 75 to 250 g / 10 min, more preferably in the range of 80 to 200 g / 10 min, and even more preferably in the range of 85 to 180 g / 10 min.

[0167] Furthermore, the total polymonomer content, preferably ethylene (C2) content, of the combined first, second, third, and fourth propylene polymer fractions is in the range of 5.5 to 12.5 wt%, more preferably in the range of 6.0 to 12.0 wt%, and more preferably in the range of 6.5 to 11.5 wt%, based on the total weight of the combined first, second, third, and fourth propylene polymer fractions, is determined quantitatively. 13 FT-IR spectroscopy determination calibrated by C-NMR spectroscopy.

[0168] The first, second, third and fourth propylene polymer fractions are preferably combined to form a multiphase propylene copolymer.

[0169] The preparation of the first, second, third and fourth propylene polymer fractions may include prepolymerization in a prepolymerization reactor upstream of the first polymerization reactor, in addition to the (main) polymerization stages in at least four polymerization reactors.

[0170] Polypropylene is produced in a prepolymerization reactor. Prepolymerization is preferably carried out in the presence of a Ziegler-Natta catalyst system. According to this embodiment, the Ziegler-Natta catalyst system introduces the prepolymerization step. However, this does not preclude the option of further adding a co-catalyst in subsequent stages, such as in a first reactor. In one embodiment, if prepolymerization is used, all components of the Ziegler-Natta catalyst system are added only in the prepolymerization reactor.

[0171] The prepolymerization reaction is usually carried out at a temperature of 0 to 60°C, preferably between 15 and 50°C, and more preferably between 20 and 45°C.

[0172] The pressure in the prepolymerization reactor is not critical, but it must be high enough to keep the reaction mixture in the liquid phase. Therefore, the pressure can be 20 to 100 bar, for example, 30 to 70 bar.

[0173] In a preferred embodiment, the prepolymerization reaction is carried out in liquid propylene in the form of bulk slurry polymerization, i.e., the liquid phase mainly comprises propylene and optionally includes inert components dissolved therein.

[0174] Other components may also be added during the prepolymerization stage. For example, hydrogen can be added during the prepolymerization stage to control the molecular weight of polypropylene, as is well known in the art. Furthermore, antistatic additives can be used to prevent particles from adhering to each other or to the reactor walls.

[0175] Precise control of prepolymerization reaction conditions and reaction parameters is a well-known technique in this field.

[0176] Due to the process conditions defined in the prepolymerization reaction, a mixture of the Ziegler-Natta catalyst system and the polypropylene prepared in the prepolymerization reactor is preferably obtained. Preferably, the Ziegler-Natta catalyst system is (finely) dispersed in the polypropylene. In other words, the Ziegler-Natta catalyst system introduced in the prepolymerization reactor is broken down into smaller fragments that are uniformly distributed within the grown polypropylene. The size of the introduced Ziegler-Natta catalyst system and the resulting fragments are not essentially relevant to the present invention and are within the scope of expertise.

[0177] As described above, if prepolymerization is used, after prepolymerization, the mixture of the Ziegler-Natta catalyst system and the polypropylene prepared in the prepolymerization reactor is transferred to the first polymerization reactor. Typically, the total amount of polypropylene produced in the first, second, and third propylene polymer fractions produced in the prepolymerization reactor is quite low, usually not exceeding 5.0 wt%, preferably not exceeding 4.0 wt%, more preferably in the range of 0.5 to 4.0 wt%, for example in the range of 1.0 to 3.0 wt%.

[0178] Without using prepolymerization, propylene and other components (such as the Ziegler-Natta catalyst system) are directly introduced into the first polymerization reactor.

[0179] The residence time of the polymerization mixture at different polymerization stages was adjusted to obtain the amounts of the first, second, third, and fourth polymer fractions in the combined first, second, third, and fourth polymer fractions.

[0180] Preferably, the content of the first propylene polymer fraction is between 35 and 55 wt%, more preferably between 40 and 50 wt%, based on the total weight of the combined first, second, third, and fourth propylene polymer fractions. The amount of polypropylene generated in the prepolymerization reactor (if present) is typically added to the amount of the first propylene polymer fraction.

[0181] Preferably, the content of the second propylene polymer fraction is 25 to 45 wt%, more preferably 30 to 40 wt%, based on the total weight of the combined first, second, third and fourth propylene polymer fractions.

[0182] Preferably, the content of the third propylene polymer fraction is 5 to 20 wt%, more preferably 10 to 15 wt%, based on the total weight of the combined first, second, third and fourth propylene polymer fractions.

[0183] Preferably, the content of the fourth propylene polymer fraction is 3 to 15 wt%, more preferably 5 to 10 wt%, based on the total weight of the combined first, second, third and fourth propylene polymer fractions.

[0184] According to the present invention, the multiphase propylene copolymer (A) is obtained by the above-described multi-stage polymerization process in the presence of a Ziegler-Natta catalyst system.

[0185] As described above, in the specific process for preparing multiphase propylene copolymer (A), a specific Ziegler-Natta catalyst is preferably used.

[0186] Therefore, the Ziegler-Natta catalyst system is described in detail.

[0187] The catalyst used in this invention is a solid Ziegler-Natta catalyst, comprising compounds of IUPAC Group 4 to 6 transition metals (such as titanium), compounds of Group 2 metals (such as magnesium), and an internal donor (preferably a non-phthalic acid compound, more preferably a non-phthalic acid ester, and even more preferably a diester of a non-phthalic acid dicarboxylic acid), which will be described in more detail below. Therefore, the catalyst is completely free of unwanted phthalic acid compounds. Furthermore, the solid catalyst is self-supporting and contains no external supporting materials such as silica or MgCl2.

[0188] Ziegler-Natta catalysts (ZN-C) can be further defined according to their acquisition method.

[0189] Ziegler-Natta catalyst (ZN-C) is preferably obtained through a process including the following steps:

[0190] a)

[0191] a1) Provides a solution of at least one Group 2 metal alkoxy compound (Ax), the compound being a reaction product of a Group 2 metal compound and a monohydric alcohol (A), and optionally including at least one ether moiety in an organic liquid reaction medium in addition to the hydroxyl moiety; or

[0192] a2) A solution of at least one Group 2 metal alkoxy compound (Ax'), the compound being the product of a reaction of a Group 2 metal compound with an alcohol mixture of monohydric alcohols (A) and (B) of formula ROH, optionally in an organic liquid reaction medium; or

[0193] a3) Provide a solution of a mixture of a group 2 alkoxy compound (Ax) and a group 2 metal alkoxy compound (Bx), wherein the compound (Bx) is the product of the reaction of a group 2 metal compound and a monohydric alcohol (B), optionally in an organic liquid reaction medium; or

[0194] a4) Provide a solution of a Group 2 alkoxy compound with the chemical formula M(OR1). m (OR2) m (OR2) m X 2-n-m Or group 2 alkoxy compounds M(OR1) n’ X 2-n’ And M(OR1) m 'X 2-m’ A mixture of M, where M is a Group 2 metal, X is a halogen, and R1 and R2 are C2 to C3 halogens. 16 Different alkyl groups with carbon atoms, where 0 ≤ n < 2, 0 ≤ m < 2, and n + m + (2 - nm) = 2, provided that n and m are both not equal to 0, 0 < n' ≤ 2, and 0 < m' ≤ 2; and

[0195] b) Add the solution obtained in step a) to at least one compound of group 4 to 6 transition metals, and

[0196] c) Obtain solid catalyst component particles.

[0197] An internal electron donor, preferably a non-phthalic acid internal donor, is added in any step prior to step c).

[0198] Preferably, the internal donor or its precursor is added to the solution in step a).

[0199] According to the above procedure, the Ziegler-Natta catalyst can be obtained by precipitation or by emulsion (liquid / liquid two-phase system)-coagulation method, depending on the physical conditions, especially the temperature used in steps b) and c).

[0200] In both methods (precipitation or emulsion-coagulation), the chemical properties of the catalyst are the same.

[0201] In the precipitation method, the solution of step a) is combined with at least one transition metal compound in step b), and the entire reaction mixture is maintained at at least 50°C, more preferably in the range of 55°C to 110°C, and even more preferably in the range of 70°C to 100°C, to ensure that the catalyst component is completely precipitated in the form of solid particles (step c).

[0202] In the emulsion-coagulation process of step b), the solution from step a) is typically added to at least one transition metal compound at a relatively low temperature, for example, between -10 and below 50°C, preferably between -5 and 30°C. While stirring the emulsion, the temperature is typically maintained between -10 and below 40°C, preferably between -5 and 30°C. Droplets of the dispersed phase of the emulsion form an active catalyst composition. The droplets are appropriately coagulated (step c) by heating the emulsion to a temperature of 70 to 150°C, preferably 80 to 110°C.

[0203] The catalyst prepared by the emulsion-coagulation method is preferred in this invention.

[0204] In a preferred embodiment, step a) uses a solution of a2) or a3), i.e., a solution of (Ax') or a mixture of (Ax) and (Bx).

[0205] Preferably, the Group 2 metal is magnesium.

[0206] Magnesium alkoxy compounds (Ax), (Ax') and (Bx) can be prepared in situ in the first step (step a) of the catalyst preparation process by reacting a magnesium compound with the above-mentioned alcohol, or the magnesium alkoxy compounds can be prepared separately, or they can even be commercially available as ready-made magnesium alkoxy compounds and used directly in the catalyst preparation process of the present invention.

[0207] An illustrative example of alcohol (A) is a monoether of a diol (ethylene glycol monoether). Preferred alcohol (A) is a C2 to C4 ethylene glycol monoether, wherein the ether moiety contains 2 to 18 carbon atoms, preferably 4 to 12 carbon atoms. Preferred examples are 2-(2-ethylhexyloxy)ethanol, 2-butoxyethanol, 2-hexyloxyethanol, and 1,3-propanediol monobutyl ether, 3-butoxy-2-propanol, wherein 2-(2-ethylhexyloxy)ethanol and 1,3-propanediol monobutyl ether, particularly 3-butoxy-2-propanol, are preferred.

[0208] The exemplary monohydric alcohol (B) has the chemical formula ROH, where R is a straight-chain or branched C6-C group. 10 Alkyl residue. The most preferred monohydric alcohol is 2-ethyl-1-hexanol or octanol.

[0209] It is preferred to use a mixture of magnesium alkoxy compounds (Ax) and (Bx) or a mixture of alcohols (A) and (B) in a molar ratio of Bx:Ax or B:A of 8:1 to 2:1, more preferably 5:1 to 3:1.

[0210] Magnesium alkoxy compounds can be the reaction products of alcohols as defined above with magnesium compounds selected from dialkylmagnesium, alkylmagnesium alkoxides, diol magnesium, alkoxymagnesium halides, and alkyl magnesium halides. The alkyl group can be similar or different C1-C. 20 Alkyl groups, preferably C2-C 10 Alkyl groups. Typical alkyl-alkoxy magnesium compounds used are ethylbutoxy magnesium, butylpentoxy magnesium, octylbutoxy magnesium, and octyloctoxy magnesium. Dialkyl magnesium is preferred. The most preferred dialkyl magnesium is butyloctyl magnesium or butylethyl magnesium.

[0211] It is also possible that magnesium compounds, in addition to reacting with alcohols (A) and (B), can also react with formula R"(OH). m The reaction is carried out with a polyol (C) to obtain the magnesium alkoxy compound. If a polyol is used, it is preferably an alcohol, wherein R” is a straight-chain, cyclic, or branched C2 to C10 hydrocarbon residue, and m is an integer from 2 to 6.

[0212] The magnesium alkoxy compound in step a) may be selected from magnesium dialkoxy, magnesium diaryloxy, magnesium alkoxyhalides, magnesium aryloxyhalides, magnesium alkylalkoxy, magnesium arylalkoxy, and magnesium alkylaryloxy. Alternatively, a mixture of magnesium dihalides and magnesium dialkoxy can be used.

[0213] The solvent used to prepare this catalyst can be selected from aromatic and aliphatic straight-chain, branched, and cyclic hydrocarbons, or mixtures thereof, having 5 to 20 carbon atoms, preferably 5 to 12 carbon atoms. Suitable solvents include benzene, toluene, cumene, xylene, pentane, hexane, heptane, octane, and nonane. Hexane and pentane are particularly preferred.

[0214] As described above, magnesium compounds are provided in the form of solutions of 10 to 50 wt% in the aforementioned solvents. Typical commercially available magnesium compounds, particularly dialkylmagnesium solutions, are 20-40 wt% toluene or heptane solutions.

[0215] The preparation of magnesium alkoxy compounds can be carried out at temperatures ranging from 40°C to 70°C. The optimal temperature depends on the magnesium compound and alcohol used.

[0216] Transition metal compounds from groups 4 to 6 are preferably titanium compounds, and most preferably titanium halides, such as TiCl4.

[0217] The non-phthalic acid internal donors used to prepare the catalyst of the present invention are preferably selected from non-phthalic acid carboxylic acid (di) esters, 1,3-diethers, and their derivatives and mixtures. Particularly preferred donors are diesters of monounsaturated dicarboxylic acids, especially esters belonging to malonic acid esters, maleic acid esters, succinic acid esters, citrate esters, glutaric acid esters, cyclohexene-1,2-dicarboxylic acid esters, and benzoic acid esters, and any derivatives and / or mixtures thereof. Preferred examples are substituted maleic acid esters and citraconates, with citraconates being the most preferred.

[0218] In emulsion methods, a two-phase liquid-liquid system can be formed by simple stirring and optionally by adding (further) solvents and additives, such as turbulence minimizing agents (TMAs) and / or emulsifiers and / or emulsion stabilizers (e.g., surfactants), which are used in a manner known in the art to promote emulsion formation and / or stabilization. Preferably, the surfactant is an acrylic or methacrylic acid polymer. Particularly preferred are unbranched C... 12 To C 20 (Meth)acrylates, such as poly(hexadecyl)-methacrylate and poly(octadecyl)-methacrylate and mixtures thereof. If a turbulence minimizing agent (TMA) is used, α-olefin polymers selected from α-olefin monomers having 6 to 20 carbon atoms, such as polyoctene, polynonene, polydecene, polyundecene, or polydodecene or mixtures thereof, are preferred. Polydecene is most preferred.

[0219] Solid particles obtained by precipitation or emulsion-coagulation can be washed at least once, preferably at least twice, and more preferably at least three times, with aromatic hydrocarbons and / or aliphatic hydrocarbons, preferably toluene, heptane, or pentane. The catalyst can be further dried, for example by evaporation or rinsing with nitrogen, or it can be slurried into an oily liquid without any drying step.

[0220] The resulting Ziegler-Natta catalyst ideally exists in particulate form, typically with an average particle size ranging from 5 to 200 μm, preferably from 10 to 100 μm. The particles are compact and have low porosity, with a surface area of ​​less than 20 g / m². 2 More preferably, below 10g / m 2 The catalyst composition typically contains 1 to 6 wt% titanium, 10 to 20 wt% magnesium, and 10 to 40 wt% donor.

[0221] Detailed preparation methods for the catalyst are disclosed in WO 2012 / 007430, EP2610271, EP261027 and EP2610272, which are incorporated herein by reference.

[0222] Ziegler-Natta catalysts are typically used in conjunction with alkylaluminum co-catalysts, and are preferably used in conjunction with external donors.

[0223] In this polymerization process, it is preferable to have an external donor as a further component. Suitable external donors include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds, and mixtures thereof. Silanes are particularly preferred. Silanes having the following general formula are most preferred:

[0224]

[0225] Where R a R b and R c This represents a hydrocarbon free radical, particularly an alkyl or cycloalkyl group, where p and q are numbers from 0 to 3, and their sum p+q is equal to or less than 3. R a R b and R c They can be chosen independently of each other and can be the same or different. Specific examples of such silanes are (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si(OCH3)2, (phenyl)2Si(OCH3)2, and (cyclopentyl)2Si(OCH3)2, or have the following general formula:

[0226] Si(OCH2CH3)3(NR 3 R 4 )

[0227] Where R 3 and R 4 They can be the same or different, representing hydrocarbon groups with 1 to 12 carbon atoms.

[0228] R 3 and R 4 The group is independently selected from linear aliphatic hydrocarbon groups having 1 to 12 carbon atoms, branched aliphatic hydrocarbon groups having 1 to 12 carbon atoms, and cyclic aliphatic hydrocarbon groups having 1 to 12 carbon atoms. Particularly preferred is R. 3 and R 4 It is independently selected from methyl, ethyl, n-propyl, n-butyl, octyl, decyl, isopropyl, isobutyl, isopentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl, and cycloheptyl.

[0229] More preferably, R 3 and R 4 They are all the same, and even more so, R 3 and R 4 They are all ethyl groups.

[0230] The preferred external donor is a dicyclopentyldimethoxysilane donor (D-donor) or a cyclohexylmethyldimethoxysilane donor (C-donor).

[0231] In addition to the Ziegler-Natta catalyst, a co-catalyst must be used, and an optional external donor can be used. The co-catalyst is preferably a compound of Group 13 of the periodic table (IUPAC), such as an organoaluminum compound, like an aluminum alkyl, aluminum halide, or aluminum alkyl halide compound. Therefore, in one specific embodiment, the co-catalyst is a trialkylaluminum, such as triethylaluminum (TEAL), dialkylaluminum chloride, or alkylaluminum dichloride, or a mixture thereof. In one specific embodiment, the co-catalyst is triethylaluminum (TEAL).

[0232] Preferably, the ratio of cocatalyst (Co) to external donor (ED) [Co / ED] and / or the ratio of cocatalyst (Co) to transition metal (TM) [Co / TM] should be carefully selected.

[0233] therefore,

[0234] (a) The molar ratio of the co-catalyst (Co) to the external donor (ED) [Co / ED] must be in the range of 10 to 50, preferably in the range of 15 to 40, more preferably in the range of 15 to 35; and optionally...

[0235] (b) The molar ratio of the co-catalyst (Co) to the titanium compound (TC) [Co / TC] must be in the range of 50 to 350.

[0236] Preferably in the range of 75 to 300, more preferably in the range of 100 to 275.

[0237] The first multiphase propylene copolymer (A) of the present invention is preferably produced in the presence of the following substances:

[0238] (a) A Ziegler-Natta catalyst comprising a Group 4 to 6 transition metal compound (TC), a Group 2 metal compound and an internal donor of IUPAC, wherein the internal donor is a non-phthalic acid compound, preferably a non-phthalic acid ester, more preferably a diester of a non-phthalic acid dicarboxylic acid.

[0239] (b) Optional co-catalyst (Co), and

[0240] (c) Optional external donor (ED).

[0241] Preferably, the internal donor (ID) is selected from any substituted malonate, maleate, succinate, glutarate, cyclohexene-1,2-dicarboxylate, benzoate and their derivatives and / or mixtures thereof, with the internal donor (ID) preferably being a citrate. Additionally or alternatively, the molar ratio of the co-catalyst (Co) to the external donor (ED) [Co / ED] is from 10 to 50.

[0242] Preferably, an additional nucleating agent is introduced into the composition during the polymerization of the multiphase polypropylene copolymer (A). The additional nucleating agent is preferably a polymerization nucleating agent, which is preferably prepared by polymerizing a vinyl compound. In the presence of a Ziegler-Natta catalyst system and the resulting vinyl compound (preferably a vinylcyclohexane (VCH) polymer), the multiphase polypropylene copolymer (A) is produced by first polymerizing the vinyl compound (preferably a vinylcycloalkane) and introducing the additional nucleating agent into the multiphase polypropylene copolymer (A), and then using the catalyst system. The above-described introduction of a polymerization nucleating agent into the multiphase polypropylene copolymer (A) during its polymerization is referred to as the BNT technique.

[0243] For information on BNT technology, please refer to international patent applications WO 99 / 24478 and WO 99 / 24479, and especially WO 00 / 68315. According to this technology, a catalyst system, preferably a Ziegler-Natta pre-catalyst, can be modified by polymerizing a vinyl compound in the presence of the catalyst system, which comprises a specific Ziegler-Natta catalyst, an external donor, and a co-catalyst, the vinyl compound having the molecular formula: CH2=CH-CHR 1 R 2 .

[0244] Among them, R 1 and R 2 Together with the carbon atoms to which they are attached, they form optionally substituted saturated or unsaturated or aromatic or fused ring systems, wherein the ring or fused ring portion contains 4 to 20 carbon atoms, preferably 5- to 12-membered saturated or unsaturated or aromatic or fused rings, or independently represented as straight-chain or branched C4-C. 30 Alkanes, C4-C 20 Cycloalkanes or C4-C 20 Aromatic ring. Preferably, R 1 and R 2 Together with the C atoms to which they are attached, they form five- or six-membered saturated or unsaturated or aromatic rings, or independently represent lower alkyl groups comprising 1 to 4 carbon atoms. Preferably, the vinyl compounds used to prepare the polymerization nucleating agents used in this invention are, in particular, vinylcycloalkanes, especially vinylcyclohexane (VCH), vinylcyclopentane, and vinyl-2-methylcyclohexane, 3-methyl-1-butene, 3-ethyl-1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, or mixtures thereof. VCH is a particularly preferred monomer.

[0245] The polymerized vinyl compound acts as an α-nucleating agent. In the catalyst modification step, the weight ratio of the vinyl compound to the solid catalyst component is preferably up to 5 (5:1), more preferably up to 3 (3:1), and even more preferably from 0.5 (1:2) to 2 (2:1). The most preferred vinyl compound is cyclohexene (VCH).

[0246] When an additional nucleating agent is introduced into the multiphase propylene copolymer (A) during polymerization, the amount of the additional nucleating agent present in the multiphase propylene copolymer (A) is preferably no more than 500 ppm, more preferably no more than 200 ppm, even more preferably in the range of 1.0 to 200 ppm, and most preferably 5.0 to 100 ppm, based on the total weight of the multiphase propylene copolymer (A) and the additional nucleating agent, preferably based on the total weight of the polypropylene composition.

[0247] A polypropylene composition is prepared by blending a multiphase polypropylene copolymer (A) and a particulate inorganic nucleating agent (B) with optional additives. Therefore, the blending conditions are preferably within the typical range for blending such polypropylene compositions and can be readily adjusted by those skilled in the art.

[0248] Products

[0249] On the other hand, the present invention relates to an article, preferably a molded article, more preferably an injection-molded article, and even more preferably an injection-molded automotive article comprising the polypropylene composition described above or below.

[0250] The article preferably contains a polypropylene composition in the range of 25 wt% to 100 wt%.

[0251] In one embodiment, the article preferably contains 90 to 100 wt% of the polypropylene composition, more preferably 95 to 100 wt%.

[0252] In the above embodiments, the article has the same properties as the polypropylene composition described above or below.

[0253] The product preferably exhibits high post-processing dimensional stability and a low initial coefficient of linear thermal expansion (CLTE).

[0254] The product, in the machine direction, at a heating rate of 1 °C / min, has a linear coefficient of thermal expansion (CLTE 23-80 °C, MD) of less than 130 μm / m °C in the temperature range of +23 to +80 °C, preferably between 115 and 129 μm / m °C.

[0255] Furthermore, the product has a linear coefficient of thermal expansion (CLTE 23-80℃, TD) of less than 140 μm / m℃ in the transverse direction at a heating rate of 1℃ / min, preferably between 125 and 139 μm / m℃ in the temperature range of +23 to +80℃.

[0256] Furthermore, the product has a linear coefficient of thermal expansion (CLTE-30-80℃, MD) of less than 115 μm / m℃ in the machine direction at a heating rate of 1℃ / min over a temperature range of -30 to +80℃, preferably between 100 and 114 μm / m℃.

[0257] Furthermore, the product has a linear coefficient of thermal expansion (CLTE-30-80℃, TD) of less than 125 μm / m℃ in the transverse direction at a heating rate of 1℃ / min, preferably between 110 and 124 μm / m℃ in the temperature range of -30 to +80℃.

[0258] Due to its superior balance, this product meets the requirements for automotive products. It has a wide range of applications, suitable for both interior and exterior automotive use.

[0259] use

[0260] In another aspect, the present invention relates to the use of the above-described or below-described polypropylene compositions in injection-molded articles, preferably automotive articles.

[0261] Experimental Section

[0262] The following examples illustrate certain aspects and implementations of the invention as described in the claims. However, those skilled in the art will understand that the following description is illustrative only and should not be construed as limiting the invention in any way.

[0263] Test methods

[0264] a)CRYSTEX

[0265] Determination of crystalline and soluble fractions and their respective properties (IV and ethylene content)

[0266] The crystalline fraction (CF) and soluble fraction (SF) of polypropylene (PP) compositions, along with the comonomer content and intrinsic viscosity of each fraction, were analyzed using a CRYSTEX instrument from Polymer Char (Valencia, Spain). Detailed information on this technique and method can be found in the literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer, and Markus Gahleitner (2020). Rapid characterization of high-impact ethylene-propylene copolymer compositions by crystallization extraction: comparability with standard separation methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596).

[0267] Crystalline and amorphous fractions were separated by temperature cycling of dissolution at 160 °C, crystallization at 40 °C, and redissolution at 160 °C in 1,2,4-trichlorobenzene. SF and CF were quantified using an integrated infrared detector (IR4), and the ethylene content (C2) was determined. Intrinsic viscosity (iV) was measured using an online 2-capillary viscometer.

[0268] The IR4 detector is a multi-wavelength detector that measures infrared absorption (CH3 stretching vibration, centered at approximately 2960 cm⁻¹) in two different wavelength bands. -1 (at the location) and CH stretching vibration (2700-3000cm) -1 The IR4 detector is used to determine the concentration and ethylene content in ethylene-propylene copolymers. It is calibrated using a series of eight EP copolymers with known ethylene contents ranging from 2 wt% to 69 wt%. 13 (C-NMR determination), the concentration of each copolymer was between 2 and 13 mg / ml. To simultaneously account for both the expected polymer concentrations and ethylene content during Crystex analysis, the following calibration formula was used:

[0269] Concentration = a + b * Abs(CH) + c * (Abs(CH)) 2 +d*(Abs(CH3))+e*(Abs(CH3)) 2 +f*

[0270] Abs(CH)*Abs(CH3)(Formula 1)

[0271]

[0272] The constants a to e in Formula 1 and the constants a to f in Formula 2 were determined using least squares regression analysis. CH3 / 1000C was converted to ethylene content (wt%) using the following formula:

[0273]

[0274] XS calibration correlates the amounts of soluble fraction (SF) and crystalline fraction (CF) with the amounts of xylene cold-soluble fraction (XCS) and xylene cold-insoluble fraction (XCI), determined according to ISO 16152, standard gravimetric method. XS calibration is achieved by testing various EP copolymers with XS content ranging from 2-31 wt%. The determined XS calibration is linear.

[0275] wt% XS=1,01*wt% SF (Formula 4)

[0276] The intrinsic viscosity (iV) of the parent EP copolymer and its soluble and crystalline fractions were determined using an online 2-capillary viscometer and correlated with the corresponding iV determined in decahydronaphthalene according to the standard method of ISO 1628-3. Calibration was performed using various EP / PP copolymers with iV = 2-4 dL / g. The determined calibration curves were linear.

[0277]

[0278] The sample to be analyzed was weighed at a concentration of 10 mg / ml to 20 mg / ml. To avoid injecting gels and / or polymers, such as PET and PA, that may be insoluble in TCB at 160°C, the weighed sample was filled into a stainless steel mesh MW 0.077 / D0.05 mm.

[0279] After automatically injecting 1,2,4-TCB containing 250 mg / L 2,6-tert-butyl-4-methylphenol (BHT) as an antioxidant into the vial, the sample was dissolved at 160°C until completely dissolved, typically with constant stirring at 400 rpm for 60 minutes. To prevent sample degradation, the polymer solution was covered with a nitrogen atmosphere during the dissolution process.

[0280] A specified volume of sample solution is injected into a chromatographic column filled with an inert support, where sample crystallization and separation of the soluble fraction from the crystalline fraction are performed. This process is repeated twice. During the first injection, the entire sample is measured at high temperature to determine the iV [dl / g] and C2 [wt%] of the PP component. During the second injection, the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) are measured during the crystallization cycle (wt% SF, wt% C2, iV).

[0281] b) Xylene cold soluble fraction (XCS, wt%)

[0282] According to ISO 16152 standard, first edition, 2005-07-01, the xylene cold soluble fraction (XCS) is determined at 25°C. The remaining insoluble fraction is the xylene cold insoluble fraction (XCI).

[0283] c) Inherent viscosity

[0284] According to DIN ISO 1628 / 1 standard, in October 1999, the intrinsic viscosity of decahydronaphthalene was measured at 135°C.

[0285] d) Charpy notch impact strength

[0286] According to ISO 179-1eA, at +23°C and -20°C, the 80x10x4mm diameter sheet prepared according to EN ISO 1873-2 is subjected to [further testing / treatment]. 3 The injection-molded specimens were tested. The measurements were performed after the specimens had been conditioned at 23°C for 96 hours.

[0287] e) Tensile properties

[0288] Tensile modulus, yield elongation, and elongation at break were tested using injection-molded specimen 1B (dog bone shape, 4 mm thickness) prepared according to EN ISO 1873-2 standard (crosshead speed = 1 mm / min; test speed 50 mm / min, 23°C). The tests were conducted after the specimens had been conditioned at 23°C for 96 hours.

[0289] f) Instrument puncture test

[0290] According to ISO 6603-2:2000, the 60x60x3mm material is tested at 23℃ and -30℃. 3 Instrument puncture tests were performed on injection-molded plaques. The tests were conducted after the samples had been conditioned at 23°C, -20°C, and -30°C for 96 hours.

[0291] g) Comonomer content

[0292] Poly(propylene-co-ethylene) -- Ethylene content -- Infrared spectroscopy

[0293] The ethylene content in poly(ethylene-co-propylene) copolymers was quantified using quantitative infrared (IR) spectroscopy, calibrated with a primary method. Calibration was performed using a set of methods... 13Internal, non-commercial calibration standards for the quantitative determination of known ethylene content using C20 solution-state nuclear magnetic resonance (NMR) spectroscopy. Calibration procedures were performed using standard methods described in the literature. The calibration set consisted of 38 calibration standards with ethylene contents ranging from 0.2% to 75.0% wt%, tested under various conditions or in full-scale production. The calibration set was selected to reflect the typical copolymers encountered in the final quantitative infrared spectroscopy. Quantitative IR spectra were performed in the solid state using a Bruker Vertex 70 FTIR spectrometer. Spectra were measured on 300 μm thick 25 x 25 mm square films prepared under compression molding at 180–210 °C and 4–6 MPa. For samples with very high ethylene contents (>50 mol%), 100 μm thick films were used. Standard transmission FT-IR spectroscopy was employed, using 5000–500 cm⁻¹. -1 The spectral range is [not specified], the aperture is 6 mm, and the spectral resolution is 2 cm⁻¹. -1 Sixteen background scans, sixteen spectral scans, an interferogram zero-fill factor of 64, and Blackmann-Harris 3-period telephotos were performed. Quantitative analysis was conducted using data corresponding to (CH2). >2 The structural units of 730 and 720cm -1 (A Q The total area of ​​CH2 rocking deformation at point ) was analyzed using the integral method G, with limits of 762 and 694 cm. -1 The quantitative spectral bands were normalized to 4323 cm⁻¹ corresponding to the CH structural unit. -1 CH band area at (A) R (Integral method G, limit value 4650, 4007cm) -1 Then, the normalized absorbance (A) was obtained using a secondary calibration curve. Q / A R The ethylene content is predicted as a weight percentage. The calibration curves were previously constructed by regressing the normalized absorbance and major comonomer content measured on the calibration set using ordinary least squares (OLS).

[0294] Poly(propylene-co-ethylene)-ethylene content- 13 C NMR spectroscopy

[0295] against 1 H and 13 C. Using a Bruker Advance III 400 NMR spectrometer, the solution state was recorded at 400.15 MHz and 100.62 MHz, respectively. 13 C{ 1 ¹H NMR quantitative spectroscopy. Using… 13The optimal 10mm extended temperature probe was used at 125°C, with nitrogen gas used in all atmospheres, to record all spectra. Approximately 200 mg of material was dissolved with chromium acetylacetone (Cr(acac)3) in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) to obtain a 65 mM relaxant solution in the solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475).

[0296] To ensure solution homogeneity, after initial sample preparation in the heating block, the NMR tube was further heated in a rotary oven for at least 1 hour. After inserting the magnet, the tube was rotated at 10 Hz. This apparatus was chosen primarily to obtain high resolution and accurate quantification of ethylene content. A standard single-pulse excitation without NOE was used, with the optimal apex cone angle, a 1-second cyclic delay, and a two-stage WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transients were collected for each spectrum. 13 C{ 1 The quantitative NMR spectra were processed, integrated, and the relevant quantitative properties were determined from the integration. The chemical shifts of the solvent were used, with all chemical shifts indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm. This method can be similarly applied even without this structural unit. Characteristic signals corresponding to ethylene incorporation were observed (Cheng, HN, Macromolecules 17 (1984), 1950), and the comonomer fraction was calculated as the fraction of ethylene in the polymer relative to all monomers in the polymer.

[0297]

[0298] Through the penetration 13 C{ 1The comonomer fraction was quantified by integrating multiple signals across the entire spectral region of the H} spectrum using the method of Wang et al. (Wang, WJ, Zhu, S., Macromolecules 33 (2000), 1157). This method was chosen for its robustness and ability to account for regional defects when needed. The integration region was fine-tuned to improve applicability across the entire range of comonomer contents encountered. For systems where only isolated ethylene was observed in the PPEPP sequence, the method of Wang et al. was modified to reduce the influence of non-zero integrals at known non-existent sites. This method reduces the overestimation of ethylene content in such systems by decreasing the number of sites used to determine absolute ethylene content.

[0299] E = 0.5(S) ββ +S βγ +S βδ +0.5(S αβ +S αγ ))

[0300] By using this set of sites, the corresponding integral equation becomes

[0301] E = 0.5(I H +I G +0.5(I C +I D ))

[0302] The same notation as in Wang et al.'s article (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) is used. The formula for calculating the absolute propylene content remains unchanged. The molar percentage of the incorporated comonomer is calculated based on the molar fraction:

[0303] E(mol%) = 100 * f E

[0304] Calculate the weight percentage of the incorporated comonomer based on the mole fraction:

[0305] E(wt%) = 100 * (f E *28.06) / ((f E *28.06)+((1-f E )*42.08))

[0306] h)MFR

[0307] Melt flow rate (MFR2) is measured at 230°C (polypropylene-based materials) or 190°C (polyethylene-based materials) using a 2.16 kg load. Melt flow rate refers to the amount of polymer (in grams) extruded by the testing equipment within 10 minutes at 230°C (or 190°C) under a 2.16 kg load, according to ISO 1133 standard.

[0308] i) Density

[0309] Density was measured according to ISO 1183-187. Sample preparation was completed by compression molding according to ISO 1872-2:2007.

[0310] j) DSC analysis, melting temperature (Tm) and crystallization temperature (Tc)

[0311] Samples ranging from 5 to 7 mg were measured using a TA Instrument Q200 differential scanning calorimeter. DSC was performed according to ISO 11357 / Part 3 / Method C2, within a temperature range of -30 to +225 °C, at a scan rate of 10 °C / min in heating / cooling / heating cycles. Crystallization temperature (T c ) and crystallization enthalpy (H c The melting temperature (T) is determined by the cooling step, while the melting temperature (T) is determined by the melting step. m ) and enthalpy of fusion (H m The result is determined by the second heating step.

[0312] k) Heat distortion temperature (HDT)

[0313] HDT is prepared according to ISO 1873-2 in 80x10x4mm diameter. 3 The test was performed on injection-molded specimens and stored at +23°C for at least 96 hours prior to measurement. The test was conducted according to ISO 75, Condition B, on a planar supported specimen with a nominal surface stress of 0.45 MPa.

[0314] l) Linear thermal expansion coefficient (CLTE)

[0315] The linear coefficient of thermal expansion (CLTE) was determined according to ISO 11359-2:1999 on 20 blocks, each 10 mm in length, cut from identical injection-molded specimens, for the determination of tensile modulus. Measurements were performed in the machine direction at a heating rate of 1 °C / min within the temperature ranges of -30 to +80 °C and 23 to +80 °C, respectively.

[0316] m) Particle size of the elastomer phase

[0317] Atomic force microscopy (AFM) images are taken at -40°C from 60x60x1mm.3 The image was taken on a frozen-cut surface prepared at the center of the injection-molded specimen for instrumented puncture testing (IPT) to provide information about the dispersed phase morphology. In injection molding, the cut is made perpendicular to the flow direction and at a distance of 60 x 60 mm. 2 The planes were at a 90° angle. An Asylum AFM instrument in dynamic tapping mode was used to distinguish the crystalline PP matrix phase from the softer elastomer phase. Based on the AFM phase images, the particle size distribution of the dispersed phase was analyzed, thus providing the number-average particle size D for each sample. mean .

[0318] experiment

[0319] a) Preparation of HECO A1-A6

[0320] Catalyst system:

[0321] In the polymerization process of HECO A-1 to HECO A-6, the Ziegler-Natta type catalyst (ZN1) used in the invention example of WO 2016 / 066446 A1 was used. This catalyst prepolymerizes with vinylcyclohexane to achieve nucleation with poly(vinylcyclohexane).

[0322] Nucleation using vinylcyclohexane prepolymerization is described in detail in EP 2 960 256 B1 and EP 2 960 279 B1. These documents are incorporated herein by reference.

[0323] Polymerization of HECO A1-A6:

[0324] HECO A1-A6 were prepared in a configuration of prepolymerization / circulation reactor / gas phase reactor 1 / gas phase reactor 2 / gas phase reactor 3, respectively, followed by a granulation step. The above catalyst system was used in combination with triethylaluminum (TEAL) as a cocatalyst and dicyclopentadienyl-dimethoxysilane (donor D) as an external donor.

[0325] The polymer powders obtained from HECO A1-A5 had an elastomeric phase (expressed as XCS content) exceeding 30 wt% and a melt flow rate of approximately 15 to 40 g / 10 min. To reduce the elastomeric phase (XCS content) to below 30 wt% and increase the melt flow rate, the HECO A1-A5 polymer powders were diluted with a high-flowability propylene homopolymer, similar to the propylene homopolymer produced as a matrix material in the circulating reactor and gas-phase reactor 1. Table 1 lists the weights of the same polymer powder and propylene homopolymer blended during the dilution step, as well as the melt flow rates of the propylene homopolymer.

[0326] The diluted resins of HECO A1-A5 and the polymer powder of HECO A6 were compounded in a Coperion ZSK 47 twin-screw extruder at 220°C with 0.15 wt% of an antioxidant (Irganox B215FF from BASF, Germany; a 1:2 mixture of pentaerythritol-tetra(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, CAS No.: 6683-19-8 and tris(2,4-di-tert-butylphenyl)phosphite, CAS No.: 31570-04-4) and 0.05 wt% of calcium stearate (CAS No.: 1592-23-0, available from Faci, Italy). Table 2 lists the CRYSTEX QC analysis results and other properties of these copolymers.

[0327] Table 1: Preparation of HECO A1-A6

[0328]

[0329]

[0330] nd = Undetermined; na = Not applicable

[0331] b) Preparation of the compositions of IE1, IE2 and CE1-CE4 in Examples

[0332] The talc B used was TALC HM2, and its d 50 The d95 is 2.4 μm and d95 is 10.0 μm (measured by a settlement diagram). It is commercially available from Imifabi S.PA.

[0333] The final composition was compounded in a Coperion ZSK40 twin-screw extruder at 220°C, using the polymer and talc B as nucleating agents, as well as antioxidants, calcium stearate, and antistatic agents. Table 2 lists the compositions of each example.

[0334] Table 2 Components of the Embodiment

[0335]

[0336] c) Properties of the compositions of Examples IE1, IE2 and CE1-CE4

[0337] Table 3 shows the properties of the embodiments.

[0338] Table 3. CRYSTEX QC analysis and other properties of the compositions of Examples IE1, IE2 and CE1-CE4

[0339]

[0340]

[0341] Examples IE1 and IE2 show that the ethylene content in the soluble fraction (C2(SF)) is 28.4 wt% and 34.1 wt%, respectively, and the ethylene content ratio (C2(SF) / C2(CF)) in the soluble fraction and crystalline fraction is 12.3 and 13.6, respectively, which are significantly different from the comparative example. The examples of this invention also show the number-average particle size (D) of the elastomeric phase. mean (EPC) are 1236nm and 1256nm respectively.

[0342] Figure 1 This shows the number-average particle size (D) of the elastomer phase. 50 The relationship between ethylene content in the soluble fraction (C2(SF)) and ethylene content in the EPC fraction.

[0343] Figure 1 The figure above shows the ethylene content and average particle size (D) of the elastomer phase in the soluble fractions (C2(SF)) of Examples IE1, IE2, and CE1-CE3. 50 The relationship between (EPC) is as follows. The multiphase polypropylene copolymers of these embodiments are closely related to each other when polymerized using the same catalyst system and reactor settings. In all embodiments IE1, IE2, and CE1-CE3, the reactor conditions were adjusted to produce unimodal polypropylene homopolymers in the circulating reactor and GPR1, and unimodal propylene-ethylene copolymers in GPR2 and GPR3.

[0344] Given that the ethylene content in the soluble fraction (C2(SF)) of Example CE4 is similar to the average particle size (D) of the elastomer phase... 50 The relationship between (EPC) does not conform to the above figure. For CE4, bimodal propylene homopolymers are generated in the circulating reactor and GPR1, while unimodal propylene-ethylene copolymers are generated in GPR2 and GPR3.

[0345] The figure below shows the relationship between the ethylene content in the xylene cold-soluble fraction (C2(XCS)) and the average particle size (D) of the elastomer phase. 50 The relationship between (EPC) is illustrated by the study by Grein et al., Rheologica Acta 46(2007) 1083-1089, which first investigated the average particle size (D) of the elastomeric phase in multiphase polypropylene copolymers. mean The relationship between the ethylene content in the xylene cold-soluble fraction (C2(XCS)) and the xylene cold-soluble fraction (EPC).

[0346] Invention Examples IE1 and IE2 exhibit improved balance performance, higher tensile modulus, higher Charpy notched impact strength (especially at low temperatures), improved puncture energy (especially at low temperatures), and comparable tensile properties, impact properties, CLTE, and shrinkage rate.

[0347] These improvements are Figure 2 and Figure 3 This is reflected in the text.

[0348] Figure 2 The relationship between Charpy notched impact strength and tensile modulus at -20°C is shown for IE1, IE2, CE1-CE3, and CE4, which are reference embodiments. It can be seen that, for a given tensile modulus, the inventive compositions of Examples IE1 and IE2 exhibit improved Charpy notched impact strength at -20°C.

[0349] Figure 3 The relationship between instrument puncture test and tensile modulus at -20°C is shown for IE1, IE2, CE1-CE3, and CE4, which are reference embodiments. It can be seen that, for a given tensile modulus, the inventive compositions of Examples IE1 and IE2 show improved instrument puncture test results at -20°C.

Claims

1. A polypropylene composition comprising: (A) At least 95.0 wt% of a multiphase propylene copolymer; (B) Up to 1.5 wt% of particulate inorganic nucleating agent; All percentages refer to the total content, and The multiphase propylene copolymer A comprises a matrix phase and an elastomer phase dispersed therein, wherein the matrix phase is a unimodal propylene homopolymer, and the composition has - The soluble fraction SF and the crystalline fraction CF were determined according to the CRYSTEX QC analysis method; - The content of SF in the soluble fraction, as determined by CRYSTEX QC analysis, ranged from 17.5 wt% to 27.5 wt%. -by quantitative 13 The ethylene content (C2(SF)) of the soluble fraction determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy was between 25.0 and 40.0 wt%. -According to DIN ISO 1628 / 1, the intrinsic viscosity iV (SF) of the soluble fraction in decahydronaphthalene at 135°C is 2.0 dl / g to 3.5 dl / g; - The ethylene content ratio (C2(SF) / C2(CF)) of the soluble fraction and the crystalline fraction is 11.0 to 15.0; The intrinsic viscosity ratio iV(SF) / iV(CF) of the soluble fraction and the crystalline fraction is 2.2 to 3.0; and - The melt flow rate (MFR2) measured at 230°C and 2.16 kg according to ISO 1133 is 75 to 250 g / 10 min.

2. The polypropylene composition according to claim 1, wherein, The granular inorganic nucleating agent B is talc.

3. The polypropylene composition according to claim 1, wherein, The particulate inorganic nucleating agent B has the following characteristics: -Median particle size d before mixing 50 The range is 0.5 to 7.5 μm; and / or -Top cut particle size before mixing d 95 The range is from 2.0 to 20.0 μm.

4. The polypropylene composition according to claim 1, having the following characteristics: - The CF content of the crystalline fraction, as determined by CRYSTEX QC analysis, is in the range of 70.0 to 85.0 wt%; and / or -via quantitative 13 The ethylene content (C2(CF)) in the crystalline fraction determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy was 1.8 to 3.0 wt%; and / or - The intrinsic viscosity iV(CF) of the crystalline fraction, determined according to DIN ISO 1628 / 1 at 135°C, in decahydronaphthalene, is 0.7 to 1.7 dl / g; and / or -via quantitative 13 The total content of ethylene C2 units determined by FT-IR spectroscopy calibrated by C-NMR spectroscopy ranged from 5.5 to 12.5 wt%.

5. The polypropylene composition according to claim 1, having the following characteristics: - The number-average particle size of the elastomeric phase particles dispersed in the matrix phase, as described in the experimental section, ranged from 1150 to 1325 nm; and / or - The melting temperature Tm, determined by differential scanning calorimetry (DSC) according to ISO 11357 / Part 3 / Method C2, is 155 to 175 °C; and / or - The crystallization temperature Tc, determined by differential scanning calorimetry (DSC) according to ISO 11357 / Part 3 / Method C2, is 120 to 140 °C; and / or - Prepared according to ISO 1873-2 80×10×4mm 3 The heat distortion temperature (HDT B) measured on the injection-molded specimens ranged from 92 to 110 °C.

6. The polypropylene composition according to claim 1, having the following characteristics: - Tensile modulus of 1250 MPa to 1600 MPa; and / or - Elongation at break ranges from 4.0% to 25.0%; All measurements were performed according to ISO 527-2 at a crosshead speed of 1 mm / min, a test speed of 50 mm / min, and at 23°C using injection-molded specimens 1B prepared as described in EN ISO 1873-2 with a dog-bone shape and a thickness of 4 mm.

7. The polypropylene composition according to claim 1, having the following characteristics: - The Charpy notched impact strength (CNIS) at 23°C ranges from 2.5 to 6.4 kJ / m. 2 ; and / or -The Charpy notched impact strength (CNIS) at -20°C ranges from 2.0 to 5.5 kJ / m. 2 ; All measurements were performed according to ISO 179-1eA at +23°C and -20°C, using 80×10×4mm plates prepared according to EN ISO 1873-2. 3 The injection-molded samples were tested.

8. The polypropylene composition according to any one of claims 1 to 7, having the following characteristics: - The puncture energy, determined by instrument puncture tests conducted at 23°C according to ISO 6603-2, is 4.5 to 20.0 J, and / or - The puncture energy determined in the instrument puncture test according to ISO 6603-2 at -20°C is 3.5 to 15.0 J.

9. A method for preparing the polypropylene composition according to any one of claims 1 to 8, wherein, The multiphase propylene copolymer A is polymerized in the presence of a Ziegler-Natta catalyst system in a multi-stage process comprising at least two polymerization reactors connected in series, and the multiphase propylene copolymer A is blended with the particulate inorganic nucleating agent B.

10. The method of claim 9, comprising the following steps: a) In the presence of a Ziegler-Natta catalyst system, propylene is polymerized in a first polymerization reactor to obtain a first propylene homopolymer fraction; b) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system and the first propylene homopolymer fraction from the first polymerization reactor to the second polymerization reactor; c) In the second polymerization reactor, propylene is polymerized in the presence of a Ziegler-Natta catalyst system to obtain a second propylene homopolymer fraction; d) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction, and the second propylene homopolymer fraction from the second polymerization reactor to the third polymerization reactor; e) In the third polymerization reactor, propylene and ethylene are polymerized in the presence of a Ziegler-Natta catalyst system to obtain a first propylene-ethylene copolymer fraction; f) Transfer the polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction, the second propylene homopolymer fraction, and the first propylene-ethylene copolymer fraction from the third polymerization reactor to the fourth polymerization reactor; g) In the fourth polymerization reactor, propylene and ethylene are polymerized in the presence of a Ziegler-Natta catalyst system to obtain a second propylene-ethylene copolymer fraction; h) Take out a polymerization mixture containing the Ziegler-Natta catalyst system, the first propylene homopolymer fraction and the second propylene homopolymer fraction, and the first propylene-ethylene copolymer fraction and the second propylene-ethylene copolymer fraction from the fourth polymerization reactor; i) Obtain a multiphase propylene copolymer A, which comprises a first propylene homopolymer fraction and a second propylene homopolymer fraction, as well as a first propylene-ethylene copolymer fraction and a second propylene-ethylene copolymer fraction.

11. The method according to claim 9, wherein, The Ziegler-Natta catalyst system is a solid Ziegler-Natta catalyst system that contains compounds of transition metals from Group 4 to Group 6 of IUPAC, compounds of Group 2 metals, and internal donors.

12. The method according to claim 9, wherein, The melt flow rate (MFR2) of the mixed first and second propylene homopolymer fractions obtained from the second polymerization reactor, measured according to ISO 1133 at 230 °C and 2.16 kg, was 250-600 g / 10 min.

13. An article comprising the polypropylene composition according to any one of claims 1 to 12.

14. The article of claim 13, wherein the article has the following characteristics: - The linear coefficient of thermal expansion, measured in the machine direction at a heating rate of 1 °C / min over a temperature range of +23 to +80 °C, is less than 130 μm / m °C; and / or - The linear coefficient of thermal expansion, measured in the transverse direction at a heating rate of 1 °C / min over a temperature range of +23 to +80 °C, is less than 140 μm / m °C; and / or - The linear coefficient of thermal expansion, measured in the machine direction at a heating rate of 1 °C / min over a temperature range of -30 to +80 °C, is less than 115 μm / m °C; and / or - The linear coefficient of thermal expansion, measured in the transverse direction at a heating rate of 1℃ / min over a temperature range of -30 to +80℃, is less than 125 μm / m℃. All measurements were performed in accordance with ISO 113592:1999.

15. Use of the polypropylene composition according to any one of claims 1-8 for injection-molded articles.

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