Improved polypropylene composition for injection molded articles

Abstract

This invention relates to a propylene-ethylene random copolymer composition and articles comprising the composition, the composition comprising a combination of a polymer nucleating agent and a particulate nucleating agent.

Description

Background Technology

[0001] Injection molded parts used for containers and injection molded products, such as thin-walled packaging applications (e.g., food and medical packaging, plastic cups), polypropylene (PP) composites, and automotive applications (e.g., automotive interior parts, engine housings, automotive exterior parts, etc.), have specific requirements for the polymer materials used to produce these products.

[0002] For the mass production of injection-molded products from PP in these diverse applications, the material must possess good processability and low cycle life, and also a sufficient stiffness / impact strength balance to achieve the required strength and integrity of the final injection-molded product. Materials used in food and medical packaging should also have good sensory properties, and in some applications, good optical properties are also required.

[0003] For the purposes mentioned above, polypropylene needs to have a high melt flow rate (MFR), but increasing the MFR will also increase stiffness and impair impact strength properties.

[0004] Increasing the content of ethylene as a comonomer, for example in random copolymers of propylene and ethylene, can improve impact strength, such as Charpy notched impact strength, but it also reduces stiffness, heat resistance (HDT), and has an adverse effect on crystallization behavior (low crystallization temperature).

[0005] There is a need for improved polypropylene (PP) compositions that exhibit improved flowability (suitable for large-size molded articles), improved HDT (highest hardness), and an ideal impact strength / stiffness balance, while simultaneously possessing good color stability and sensory properties. The latter requirement effectively excludes the application of viscosity-reducing cracking grades (i.e., polymers whose MFR has been increased through a free radical-based controlled degradation process). Therefore, a particular object of the present invention is to provide a polypropylene with high flowability while maintaining high levels of impact properties and optical properties.

[0006] It has now been unexpectedly discovered that propylene-ethylene random copolymer compositions comprising a combination of a single-phase propylene-ethylene random copolymer and a polymer nucleating agent and a particulate nucleating agent result in nucleated propylene-ethylene random copolymer compositions with improved mechanical, optical, and sensory properties. Summary of the Invention

[0007] This invention relates to an α-nucleating propylene-ethylene random copolymer composition, the α-nucleating propylene-ethylene random copolymer composition comprising:

[0008] a) A single-phase propylene-ethylene random copolymer (R-PP), wherein the single-phase propylene-ethylene random copolymer (R-PP) has the following characteristics:

[0009] - Based on the total weight of the single-phase propylene-ethylene random copolymer, through 13 The ethylene content (C2) determined by C-NMR spectroscopy is 0.5 to 5.0 wt%, more preferably 0.6 to 4.0 wt%, and most preferably 0.6 to 2.5 wt%.

[0010] - The melt flow rate MFR2 (230°C) measured according to ISO 1133 is 20 to 500 g / 10 min, preferably 30 to 300 g / 10 min, more preferably 35 to 200 g / 10 min; and

[0011] b) At least two nucleating agents (NU), wherein:

[0012] - One of the at least two nucleating agents is a vinylcycloalkane polymer (NU1), preferably poly(vinylcyclopentane) (pVCP) or poly(vinylcyclohexane) (pVCH), more preferably poly(vinylcyclohexane) (pVCH);

[0013] - Another of the at least two nucleating agents (NU2) comprises a salt of bridged or non-bridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib):

[0014] ,

[0015] In the formula, x is 1 or 2, y is 1 or 2, and x For y=2, M is an alkali metal; for y=1, M is an alkaline earth metal; R 1 To R 10 Independently, it is a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 9 carbon atoms, an amino group, an alkylamine group having 1 to 9 carbon atoms, a halogen atom, a phenyl group, or a group of the formula R-(R'-O). n - indicates a group, where R is an alkyl group having 1 to 3 carbon atoms, R' is an alkylene group having 2 or 3 carbon atoms, and n is an integer from 1 to 4; and R 1 To R 10 Any two alkyl groups can be linked together to form a carbon ring with 3 to 6 carbon atoms.

[0016] The present invention also relates to an injection-molded article, preferably a thin-walled injection-molded article or a low-VOC polypropylene (PP) composite material for automotive applications (e.g., automotive interior parts, engine housings, automotive exterior parts, etc.), comprising the α-nucleating propylene-ethylene copolymer composition of the present invention. Therefore, one specific embodiment of the present invention relates to an injection-molded article, such as a thin-walled packaging element, comprising the propylene copolymer (R-PP) of the present invention. More preferably, the present invention relates to a thin-walled packaging element selected from cups, boxes, trays, buckets, barrels, bowls, lids, flip lids, caps, CD sleeves, and DVD sleeves, wherein the thin-walled packaging element comprises the propylene copolymer (R-PP) of the present invention.

[0017] definition

[0018] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. While any methods and materials similar to or equivalent to those described herein may be used in practice for testing the invention, preferred materials and methods are described herein. In describing and elucidating the invention, the following terms will be used in accordance with the definitions set forth below.

[0019] Unless otherwise expressly stated, the terms “a”, “an”, etc., are used to refer to more than one.

[0020] The propylene-ethylene random copolymer, namely the single-phase propylene-ethylene random copolymer (R-PP) according to the present invention, is a copolymer composed of propylene units and ethylene units, wherein the comonomer units (i.e. ethylene units) are randomly distributed on the polymer chain.

[0021] A typical characteristic of single-phase propylene-ethylene copolymers is the presence of only one glass transition temperature. In other words, the single-phase propylene-ethylene copolymers according to the present invention do not contain polymer components that are immiscible with each other, unlike multiphase propylene copolymers. Unlike single-phase systems, multiphase systems contain a continuous polymer phase, such as polypropylene, in which other immiscible polymers (e.g., elastomeric polymers) are dispersed as inclusions. A polypropylene system containing a polypropylene matrix and inclusions as a second polymer phase is referred to as a multiphase system, but this is not part of the present invention. The presence of the second polymer phase, or so-called inclusions, can be observed using high-resolution microscopy (e.g., electron microscopy or atomic force microscopy) or dynamic thermodynamic analysis (DMTA). Specifically, in DMTA, the presence of a multiphase structure can be identified by at least two distinct glass transition temperatures. Detailed Implementation

[0022] Single-phase propylene-ethylene random copolymer (R-PP)

[0023] The main component of the α-nucleated propylene-ethylene random copolymer composition is a single-phase propylene-ethylene random copolymer (R-PP).

[0024] Single-phase propylene-ethylene random copolymer (R-PP) through 13 The ethylene content, as determined by C-NMR spectroscopy, is 0.5-5.0 wt%, more preferably 0.6-4.0 wt%, and most preferably 0.6-2.5 wt%.

[0025] A fundamental requirement for the polypropylene compositions of this invention is their high melt flow rate. The melt flow rate depends primarily on the average molecular weight. This is because longer molecules tend to flow less readily than shorter molecules.

[0026] The single-phase propylene-ethylene random copolymer (R-PP) of the present invention has a melt flow rate (MFR2) (230°C) of 20 to 500 g / 10 min as measured according to ISO 1133, preferably 30 to 300 g / 10 min, and more preferably 35 to 200 g / 10 min.

[0027] Preferably, the single-phase propylene-ethylene random copolymer (R-PP) is obtained by quantitative analysis. 13 The 2,1- region defect content measured by C-NMR is less than 0.4 mol%, preferably 0.0 to 0.2 mol%, more preferably 0.0 to 0.2 mol%, and more preferably 0.0 to 0.2 mol%.

[0028] As used in this invention, the term "2,1-regional defect" refers to the sum of 2,1-red regional defects and 2,1-threotype regional defects.

[0029] The low content and absence of defects in region 2,1 in the single-phase random propylene-ethylene copolymer (R-PP) respectively indicate that the single-phase random propylene-ethylene copolymer (R-PP) has been polymerized in the presence of the Ziegler-Natta catalyst system (ZN).

[0030] Preferably, given the ethylene content of at least two propylene-ethylene random copolymer fractions (A) and (B), the single-phase propylene-ethylene random copolymer (R-PP) is a multi-peak single-phase propylene-ethylene random copolymer (R-PP), wherein, based on the total weight of the propylene-ethylene random copolymer (R-PP), the total amount of the two propylene-ethylene random copolymer fractions (A) and (B) is at least 90 wt%, preferably 95 to 100 wt%.

[0031] Therefore, preferably, the multimodal R-PP is a bimodal R-PP, that is, composed of two random copolymer fractions of propylene and ethylene (A) and (B).

[0032] If the single-phase propylene-ethylene random copolymer (R-PP) is a multi-peak single-phase propylene-ethylene random copolymer (R-PP), then the ethylene content of the first propylene-ethylene random copolymer fraction (A) is 0.1-1.5 wt%, more preferably 0.3-1.2 wt%, and the ethylene content of the second propylene copolymer fraction (B) is 0.8-2.5 wt%, more preferably 1.0-2.0 wt%. Preferably, the ethylene content of the first propylene-ethylene random copolymer fraction (A) is lower than the ethylene content of the second propylene copolymer fraction (B); more preferably, the ethylene content of the first propylene-ethylene random copolymer fraction (A) is at least 0.2 wt%, more preferably 0.2 to 2.0 wt%, and even more preferably 0.3 to 1.5 wt%, lower than the ethylene content of the second propylene copolymer fraction (B).

[0033] The weight ratio of the first propylene-ethylene random copolymer fraction (A) to the second propylene-ethylene random copolymer fraction (B) is 40:60 to 60:40.

[0034] The ratio of the comonomer content of the first propylene-ethylene random copolymer fraction (A) to the comonomer content of the second propylene-ethylene random copolymer fraction (B) can be 0.45-0.85, more preferably 0.50-0.80, and even more preferably 0.55-0.75.

[0035] The xylene cold soluble content (XCS) of the single-phase propylene-ethylene random copolymer (R-PP) as measured according to ISO 16152 is preferably less than 4.0 wt%, preferably 0.5-3.5 wt%, more preferably 1.0-3.0 wt%, and most preferably 1.5-2.7 wt%.

[0036] Preferably, the single-phase propylene-ethylene random copolymer (R-PP) is non-viscosity-reducing cracked, more preferably a reactor-prepared single-phase propylene-ethylene random copolymer; and / or, it does not contain peroxides or peroxide decomposition products.

[0037] Since no viscosity-reducing cracking step is required, the sensory properties of the compositions of the present invention can be improved.

[0038] The single-phase propylene-ethylene random copolymer (R-PP) preferably has a molecular weight distribution (MWD) of at least 5.0, more preferably 6.0 to 10.0, and more preferably 6.5 to 9.5, as determined by gel permeation chromatography according to ISO 16014-4:2003 and ASTM D 6474-99.

[0039] The α-nucleated propylene-ethylene random copolymer composition may contain other (polymer) components.

[0040] However, the single-phase propylene-ethylene random copolymer (R-PP) as described above is the main component of the α-nucleated propylene-ethylene random copolymer composition of the present invention.

[0041] Therefore, preferably, based on the total weight of the propylene-ethylene random copolymer composition, the content of single-phase propylene-ethylene random copolymer (R-PP) is greater than 85 wt%, preferably 90 to 99.9 wt%, and more preferably 95 to 99.9 wt%.

[0042] nucleating agent

[0043] The propylene-ethylene random copolymer composition of the present invention further comprises at least two nucleating agents (NU).

[0044] Of these at least two nucleating agents, one is a vinyl cycloalkane polymer (NU1).

[0045] Polymer nucleating agents can be achieved through specialized reactor techniques, in which the catalyst is prepolymerized with monomers such as vinylcyclohexane (VCH); or by blending a polypropylene composition with a vinylcycloalkane polymer. These methods are described in more detail in, for example, EP0316187A2, WO99 / 24479 and EP2960279A1.

[0046] Preferably, the polymer nucleating agent (NU1) is implemented as follows: the catalyst system (preferably the Ziegler-Natta catalyst system) is prepolymerized with the monomer of the vinyl cycloalkane polymer before the catalyst system is used for the polymerization of the propylene-ethylene random copolymer (R-PP).

[0047] The polymer nucleating agent, vinylcycloalkane polymer (NU1), is preferably poly(vinylcyclopentane) (pVCP) or poly(vinylcyclohexane) (pVCH). Even more preferably, the polymer nucleating agent, vinylcycloalkane polymer (NU1), is polyvinylcyclohexane (pVCH).

[0048] Based on the total weight of the propylene-ethylene random copolymer composition, the content of vinyl cycloalkane polymer (NU1) in the composition is preferably 0.1-2000 ppm, more preferably 1.0-1000 ppm.

[0049] In addition to the polymer nucleating agent (NU1), the propylene-ethylene random copolymer composition of the present invention also contains a particulate nucleating agent (NU2).

[0050] The particulate nucleating agent (NU2) according to the present invention comprises a salt of bridged or non-bridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib):

[0051] ,

[0052] In the formula, x is 1 or 2, y is 1 or 2, and x For y=2, M is an alkali metal; for y=1, M is an alkaline earth metal; R 1 To R 10 Independently, it is a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 9 carbon atoms, an amino group, an alkylamine group having 1 to 9 carbon atoms, a halogen atom, a phenyl group, or a group of the formula R-(R'-O). n - indicates a group, where R is an alkyl group having 1 to 3 carbon atoms, R' is an alkylene group having 2 or 3 carbon atoms, and n is an integer from 1 to 4; and R 1 To R 10 Any two alkyl groups can be linked together to form a carbon ring with 3 to 6 carbon atoms.

[0053] To balance the negative charge of the dicarboxylate ion, the counterion xM y+ x in y must be 2.

[0054] When y=1, alkali metals can be used as M; when y=2, alkaline earth metals can be used as M.

[0055] The preferred alkali metals are lithium, sodium and potassium, with sodium being more preferred in formula (Ia).

[0056] The preferred alkaline earth metals are magnesium, calcium, strontium and barium, with calcium being more preferred in formula (Ib).

[0057] Preferably, the nucleating agent (NU2) comprises a salt of non-bridged cyclohexanedicarboxylic acid as shown in formula (Ib).

[0058] Counterion xM y+ Alkaline earth metal ions are preferred. Therefore, it is preferable that x is 1 and y is 2 in formula (Ia) or formula (Ib).

[0059] Preferably, the counter ion xM y+ It is selected from alkaline earth metals such as magnesium, calcium, strontium, or barium, with calcium being more preferred.

[0060] Preferably, all R 1 To R 10 It is a hydrogen atom.

[0061] In a preferred embodiment, the nucleating agent (NU2) comprises an alkaline earth metal salt, more preferably a calcium salt of cis-1,2-cyclohexanedicarboxylic acid as shown in formula (II):

[0062] .

[0063] More preferably, the nucleating agent (NU2) comprises a salt of bridged or non-bridged cyclohexanedicarboxylic acid as a major component. Therefore, preferably, based on the total weight of the nucleating agent (NU2), the nucleating agent (NU2) comprises ≥50 wt%, more preferably 50-100 wt%, and even more preferably 50-80 wt% of a salt of bridged or non-bridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib).

[0064] In some embodiments of the present invention, the nucleating agent (NU2) further comprises, based on the total weight of the nucleating agent (NU2), ≤50 wt%, preferably 20-45 wt%, more preferably 25-40 wt% of a metal stearate (e.g., zinc stearate).

[0065] The particulate nucleating agent (NU2) according to the present invention comprises a bridged or non-bridged cyclohexanedicarboxylic acid salt as shown in formula (Ia) or (Ib), which may be a commercial nucleating agent HPN600ei obtained from Milliken Company, containing ≥50 wt% of a calcium salt of cis-1,2-cyclohexanedicarboxylic acid as the main component and ≤40 wt% of zinc stearate as the secondary component.

[0066] Based on the total weight of the propylene-ethylene random copolymer composition, the content of the particulate nucleating agent (NU2) containing the salt of bridged or unbridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib) is preferably 20-1000 ppm, and more preferably 50-500 ppm.

[0067] The propylene-ethylene random copolymer composition may contain other nucleating agents.

[0068] However, preferably, the propylene-ethylene random copolymer composition does not contain other polymers or particulate nucleating agents, and more preferably, it does not contain any other nucleating agents.

[0069] Based on the total weight of the propylene-ethylene random copolymer composition, the total amount of propylene-ethylene random copolymer (R-PP) and at least two nucleating agents (NU) preferably exceeds 90 wt%, more preferably 95.0 to 99.9 wt%, and even more preferably 97.0 to 99.9 wt%.

[0070] α-Nucleating propylene-ethylene random copolymer composition

[0071] The combination of polymer nucleating agent (NU1) and particulate nucleating agent (NU2) unexpectedly yielded α-nucleated propylene-ethylene random copolymer compositions with improved mechanical, optical, and sensory properties.

[0072] To obtain particularly excellent results, the compositions of the present invention may have one or more of the following characteristics.

[0073] Preferably, not only is the propylene-ethylene random copolymer (R-PP) single-phase, but the propylene-ethylene random copolymer composition is also single-phase.

[0074] The composition preferably has a melt flow rate (MFR2) of 20 to 500 g / 10 min as measured according to ISO 1133, more preferably 30 to 300 g / 10 min, and even more preferably 35 to 200 g / 10 min.

[0075] The xylene soluble content (XS) of the composition, as measured at 25°C according to ISO 16152, is preferably less than 4.0 wt%, more preferably 0.5 to 3.5 wt%, more preferably 1.0 to 3.0 wt%, and even more preferably 1.5 to 2.7 wt%.

[0076] The crystallization temperature Tc of the composition, as measured by differential scanning calorimetry (DSC), is preferably at least 123°C, more preferably 124°C to 135°C.

[0077] The melting temperature Tm of the composition, as measured by differential scanning calorimetry (DSC), is preferably at least 153°C, more preferably 153°C to 160°C, and even more preferably 155.5°C to 159.0°C.

[0078] The composition was prepared according to ISO 19069-2 in an 80×10×4 mm sample. 3 The heat distortion temperature (HDT) measured on the injection-molded bar specimen at a melting temperature of 200°C is preferably greater than 110°C, and more preferably 112°C to 125°C.

[0079] The α-nucleated propylene-ethylene random copolymer composition of the present invention has improved mechanical properties. Therefore, the tensile modulus is improved while maintaining the same Charpy notched impact strength (NIS) value.

[0080] The tensile modulus of the composition, as measured according to ISO 527-1,-2 at 1 mm / min and 23°C, is preferably greater than 1800 MPa, more preferably between 1800 MPa and 2200 MPa.

[0081] The favorable balance between Charpy impact strength and stiffness properties of the compositions of the present invention is expressed herein as the ratio of tensile modulus to Charpy notched impact strength (NIS).

[0082] According to ISO 179, use injection molding of 80×10×4 mm according to ISO 19069-2. 3 The ratio of the tensile modulus to the Charpy notched impact strength (NIS) of the test bar measured at 23°C satisfies equation (a):

[0083] .

[0084] In addition to improved mechanical properties, the α-nucleated propylene-ethylene random copolymer compositions of the present invention also exhibit improved optical properties.

[0085] Therefore, according to ASTM D1003-07, for dimensions of 60×60×1 mm 3 The haze value measured on the plate is preferably less than 70%, more preferably less than 65%, for example 30% to 65%.

[0086] According to ASTM E313, the dimensions are 60×60×2 mm. 3 The yellowness index measured on the plate is preferably less than or equal to 6.0, more preferably 0.1 to 6.0, and even more preferably 0.1 to 5.5.

[0087] The components used in the α-nucleating propylene-ethylene random copolymer compositions of the present invention are known to those skilled in the art and can therefore be readily prepared based on the information provided herein.

[0088] The following describes in more detail a non-limiting example of the preparation of the nucleated propylene-ethylene random copolymer composition of the present invention.

[0089] Ziegler-Natta catalysts are modified by polymerizing vinylcyclohexane monomers and catalysts to form poly(vinylcyclohexane)-modified Ziegler-Natta catalysts. Related processes have been described in EP1028984, EP1183307, and EP2960279. Propylene and, optionally, ethylene are then polymerized in a prepolymerization reactor in the presence of the modified Ziegler-Natta catalyst. This prepolymerized, modified catalyst composition is then used for the preparation of propylene-ethylene random copolymers. Fraction (A) is prepared by polymerizing propylene and ethylene comonomers in a slurry reactor (e.g., a loop reactor) in the presence of the prepolymerized Ziegler-Natta catalyst composition. However, the polymerization of fraction (A) can be achieved in the slurry reactor without any prepolymerization step. Therefore, the first propylene-ethylene random copolymer fraction (A) according to the invention is a polymer obtained after the slurry reactor.

[0090] The fraction (A) is then transferred to a subsequent gas-phase reactor, where propylene reacts in the presence of ethylene to generate a propylene-ethylene random copolymer fraction (B) in the presence of the propylene-ethylene random copolymer fraction (A). This reaction sequence provides reactor blends of fractions (A) and (B) constituting a single-phase propylene-ethylene random copolymer (R-PP). The process discussed above, comprising at least two polymerization steps, has the advantage of providing easily controlled reaction steps to achieve the preparation of the desired reactor blends. For example, the polymerization steps can be adjusted by appropriately selecting monomer feed, comonomer feed, hydrogen feed, temperature, and pressure, thereby effectively adjusting the properties obtained from the resulting polymer product. In particular, it is possible to obtain multi-peak, preferably bi-peak, propylene-ethylene random copolymers with respect to ethylene distribution, molecular weight, and MFR2 (230°C) value during the multi-stage polymerization process.

[0091] This process can be carried out using any suitable Ziegler-Natta catalyst to prepare single-phase propylene-ethylene random copolymers (R-PP). Preferably, the process discussed above uses a Ziegler-Natta catalyst, particularly a high-yield Ziegler-Natta catalyst (so-called fourth- and fifth-generation catalysts, to distinguish them from the low-yield so-called second-generation Ziegler-Natta catalysts). According to the invention, a suitable Ziegler-Natta catalyst comprises a catalyst component, a co-catalyst component, and at least one electron donor (internal and / or external electron donor, preferably at least one external electron donor). Preferably, the catalyst component is a Ti-Mg based catalyst component, and the co-catalyst is typically an Al-alkyl compound. Suitable catalysts are disclosed in particular in US 5,234,879, WO 92 / 19653, WO 92 / 19658, and WO 99 / 33843.

[0092] Suitable external donors are known silane-based donors, such as dicyclopentyldimethoxysilane or cyclohexylmethyldimethoxysilane.

[0093] The process described may be, for example, a loop-gas phase process, such as the process developed by Borealis and called Borstar® technology as described in EP0887379A1 and WO92 / 12182.

[0094] Regarding the preferred slurry-gas phase process described above, the following general information regarding process conditions can be provided.

[0095] The temperature is 40 to 110°C, preferably 60 to 100°C, particularly preferably 70 to 90°C; the pressure is 20 to 80 bar, preferably 30 to 60 bar; hydrogen may be added to control the molecular weight. The reaction products of the slurry polymerization (preferably carried out in a loop reactor) are then transferred to a subsequent gas-phase reactor, wherein the temperature is preferably 50 to 130°C, more preferably 80 to 100°C, the pressure is 5 to 50 bar, preferably 15 to 35 bar, and hydrogen may be added to control the molecular weight.

[0096] The residence time in the reactor region described above can vary. In some embodiments, the residence time for slurry reactions (e.g., in a loop reactor) is 0.5 to 5 hours, for example 0.5 to 2 hours, while the residence time in a gas-phase reactor is typically 1 to 8 hours.

[0097] The properties of the single-phase propylene-ethylene random copolymer (R-PP) prepared by the process outlined above can be adjusted and controlled by process conditions known to those skilled in the art, for example by one or more of the following process parameters: temperature, hydrogen feed, comonomer feed, propylene feed, catalyst, type and amount of external donor, and splitting of two or more components in a multi-peak polymer.

[0098] The single-phase propylene-ethylene random copolymer (R-PP) obtained by the process described above can then be compounded with a nucleating agent (e.g., particulate nucleating agent (NU2)) and other additives to obtain the α-nucleating propylene-ethylene random copolymer composition of the present invention comprising R-PP, NU1 and NU2.

[0099] Injection molded products

[0100] Furthermore, this invention relates to injection-molded articles. The above-described α-nucleated propylene-ethylene random copolymer composition possesses excellent properties for use in injection-molded articles.

[0101] Although injection-molded articles may contain other components, preferably, the articles are mainly composed of the α-nucleated propylene-ethylene random copolymer composition as described above.

[0102] Due to the excellent mechanical, optical, and sensory properties of the propylene-ethylene random copolymer composition of the present invention, it can be injection molded into thin-walled packaging containers. In one specific embodiment, the injection-molded article (e.g., a thin-walled packaging element selected from cups, boxes, trays, buckets, barrels, bowls, lids, flip-tops, caps, CD sleeves, and DVD sleeves) comprises the propylene copolymer (R-PP) of the present invention.

[0103] Due to the high MFR2 and excellent stiffness / toughness balance of the propylene-ethylene random copolymer composition of the present invention, it can be used in a variety of automotive applications, such as automotive interior parts, engine housings, automotive exterior parts, etc., because it can meet all the specific requirements of the polymer materials that can be used to produce these articles.

[0104] Furthermore, the present invention can be described from the following aspects:

[0105] 1. An α-nucleating propylene-ethylene random copolymer composition, said α-nucleating propylene-ethylene random copolymer composition comprising:

[0106] a) A single-phase propylene-ethylene random copolymer (R-PP), wherein the single-phase propylene-ethylene random copolymer (R-PP) has the following characteristics:

[0107] - Based on the total weight of the single-phase propylene-ethylene random copolymer, through 13 The ethylene content (C2) determined by C-NMR spectroscopy is 0.5 to 5.0 wt%, more preferably 0.6 to 4.0 wt%, and most preferably 0.6 to 2.5 wt%.

[0108] - The melt flow rate MFR2 (230°C) measured according to ISO 1133 is 20 to 500 g / 10 min, preferably 30 to 300 g / 10 min, more preferably 35 to 200 g / 10 min; and

[0109] b) At least two nucleating agents (NU), wherein:

[0110] - One of the at least two nucleating agents is a vinylcycloalkane polymer (NU1), preferably poly(vinylcyclopentane) (pVCP) or poly(vinylcyclohexane) (pVCH), more preferably poly(vinylcyclohexane) (pVCH);

[0111] - Another of the at least two nucleating agents (NU2) comprises a salt of bridged or non-bridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib):

[0112] ,

[0113] In the formula, x is 1 or 2, y is 1 or 2, and x For y=2, M is an alkali metal; for y=1, M is an alkaline earth metal; R 1 To R 10 Independently, it is a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 9 carbon atoms, an amino group, an alkylamine group having 1 to 9 carbon atoms, a halogen atom, a phenyl group, or a group of the formula R-(R'-O). n- indicates a group, where R is an alkyl group having 1 to 3 carbon atoms, R' is an alkylene group having 2 or 3 carbon atoms, and n is an integer from 1 to 4; and R 1 To R 10 Any two alkyl groups can be linked together to form a carbon ring with 3 to 6 carbon atoms.

[0114] 2. The α-nucleated propylene-ethylene random copolymer composition according to aspect 1, wherein the single-phase propylene-ethylene random copolymer (R-PP) is obtained by quantitative... 13 The 2,1- region defects measured by C-NMR were less than 0.40 mol.

[0115] 3. The α-nucleating propylene-ethylene random copolymer composition according to any one of aspects 1 or 2, wherein, in formula (Ia) or (Ib), for the counterion xM y+ x is 1 and y is 2.

[0116] 4. The α-nucleating propylene-ethylene random copolymer composition according to any one of aspects 1 to 3, wherein the metal M resisting the counterion in formula (Ia) or (Ib) is selected from magnesium, calcium, strontium or barium, preferably calcium.

[0117] 5. The α-nucleating propylene-ethylene random copolymer composition according to any one of aspects 1 to 4, wherein the nucleating agent (NU2) comprises a salt of non-bridged cyclohexanedicarboxylic acid as shown in formula (Ib).

[0118] 6. The α-nucleated propylene-ethylene random copolymer composition according to any one of aspects 1 to 5, wherein the bridged or unbridged cyclohexanedicarboxylic acid salt of formula (Ia) or (Ib) is the calcium salt of cis-1,2-cyclohexanedicarboxylic acid of formula (II):

[0119] .

[0120] 7. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein, based on the total weight of the nucleating agent (NU2), the nucleating agent (NU2) comprises, on a basis of ≥50 wt%, preferably 50 to 100 wt%, and even more preferably 50 to 80 wt%, a salt of bridged or unbridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib).

[0121] 8. The α-nucleating propylene-ethylene random copolymer composition according to aspect 7, wherein, based on the total weight of the nucleating agent (NU2), the nucleating agent (NU2) further comprises ≤50 wt%, preferably 25-40 wt%, of zinc stearate.

[0122] 9. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the single-phase propylene-ethylene random copolymer (R-PP) is multi-peaked, preferably bi-peaked, single-phase propylene-ethylene random copolymer (R-PP) with respect to ethylene content, and comprises at least two propylene-ethylene random copolymer fractions (A) and (B), wherein:

[0123] - Based on the total weight of the propylene-ethylene random copolymer (R-PP), the total amount of the two propylene-ethylene random copolymer fractions (A) and (B) is at least 90 wt%;

[0124] - The ethylene content of the first propylene-ethylene random copolymer fraction (A) is 0.1 to 1.5 wt%, more preferably 0.3 to 1.2 wt%, and the ethylene content of the second propylene-ethylene random copolymer fraction (B) is 0.8 to 2.5 wt%, more preferably 1.0 to 2.0 wt%, and the ethylene content of the first propylene-ethylene random copolymer fraction (A) is lower than the ethylene content of the second propylene copolymer fraction (B). The ethylene content of the first propylene-ethylene random copolymer fraction (A) is preferably at least 0.2 wt%, more preferably 0.2 to 2.0 wt%, and even more preferably 0.3 to 1.5 wt% lower than the ethylene content of the second propylene copolymer fraction (B).

[0125] - The weight ratio between the first propylene copolymer fraction (A) and the second propylene copolymer fraction (B) is 40:60 to 60:40.

[0126] 10. The α-nucleated propylene-ethylene random copolymer composition according to aspect 9, wherein the ratio of the comonomer content of the first propylene-ethylene random copolymer fraction (A) to the comonomer content of the second propylene-ethylene random copolymer fraction (B) is 0.44 to 0.85, more preferably 0.50 to 0.80, and even more preferably 0.55 to 0.75.

[0127] 11. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the propylene-ethylene random copolymer (R-PP) is non-viscosity-reducing cracked, preferably a reactor-prepared propylene-ethylene random copolymer.

[0128] 12. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition is free of peroxides or peroxide decomposition products.

[0129] 13. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the propylene-ethylene random copolymer (R-PP) has the following characteristics:

[0130] - The molecular weight distribution (MWD) determined by gel permeation chromatography according to ISO 16014-4:2003 and ASTM D 6474-99 is at least 5.0, preferably 6.0 to 10.0, and more preferably 6.5 to 9.5.

[0131] 14. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the xylene-soluble content (XS) of the propylene-ethylene random copolymer (R-PP) as measured at 25°C according to ISO 16152 is less than 4.0 wt%, preferably 0.5 to 3.5 wt%, more preferably 1.0 to 3.0 wt%, and most preferably 1.5 to 2.7 wt%.

[0132] 15. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the content of the vinyl cycloalkane polymer (NU1) is 0.1 to 2000 ppm, preferably 1.0 to 1000 ppm, based on the total weight of the propylene-ethylene random copolymer composition.

[0133] 16. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the polymer nucleating agent (NU1) is achieved by prepolymerizing the catalyst system with the monomer of the vinyl cycloalkane polymer prior to using the catalyst system for the polymerization of the propylene-ethylene random copolymer (R-PP).

[0134] 17. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein, based on the total weight of the propylene copolymer composition, the nucleating agent (NU2) comprising the salt of bridged or unbridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib) is present in an amount of 20 to 1000 ppm, preferably 50 to 500 ppm.

[0135] 18. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition does not contain any nucleating agent other than the vinyl cycloalkane polymer (NU1) and the nucleating agent (NU2) comprising a salt of bridging or non-bridging cyclohexane dicarboxylic acid as shown in formula (Ia) or (Ib).

[0136] 19. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein, based on the total weight of the propylene-ethylene random copolymer composition, the content of the single-phase propylene-ethylene random copolymer (R-PP) is greater than 85 wt%, preferably 90 to 99.9 wt%, more preferably 95 to 99.9 wt%.

[0137] 20. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein, based on the total weight of the propylene-ethylene random copolymer composition, the total content of the propylene-ethylene random copolymer (R-PP) and at least two nucleating agents (NU) is greater than 90 wt%, preferably 95.0 to 99.9 wt%, more preferably 97.0 to 99.9 wt%.

[0138] 21. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the melt flow rate MFR2 (230°C) of the composition, as measured according to ISO 1133, is 20 to 500 g / 10 min, preferably 30 to 300 g / 10 min, more preferably 35 to 200 g / 10 min, and the xylene soluble content (XS), as measured according to ISO 16152 at 25°C, is less than 4.0 wt%.

[0139] 22. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the crystallization temperature Tc of the composition, as measured by differential scanning calorimetry (DSC), is at least 123°C, preferably 124°C to 135°C, and more preferably 125°C to 130°C.

[0140] 23. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the melting temperature Tm of the composition, as measured by differential scanning calorimetry (DSC), is at least 153°C, preferably 153°C to 170°C.

[0141] 24. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition is prepared according to ISO 19069-2 in an 80×10×4 mm diameter. 3 The heat distortion temperature (HDT) measured on the injection-molded bar sample at a melting temperature of 200°C is greater than 110°C, preferably 110°C to 130°C, and more preferably 112°C to 125°C.

[0142] 25. The α-nucleating propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition has the following characteristics:

[0143] - A tensile modulus greater than 1800 MPa, preferably between 1800 MPa and 2200 MPa, as measured according to ISO 527-1,-2 at 1 mm / min and 23°C; and

[0144] - 80×10×4 mm injection molded according to ISO 19069-2, in accordance with ISO 179. 3The ratio of the tensile modulus to the Charpy notched impact strength (NIS) of the test bar measured at 23°C satisfies equation (a):

[0145] .

[0146] 26. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition is in the form of a 60×60×1 mm substrate according to ASTM D1003-07. 3 The haze value measured on the plate is less than 70%, preferably less than 65%.

[0147] 27. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition is in the form of a 60×60×2 mm size according to ASTM E313. 3 The yellowness index measured on the plate is less than or equal to 6.0, preferably 0.1 to less than 6.0, and more preferably 0.1 to 5.5.

[0148] 28. The α-nucleated propylene-ethylene random copolymer composition according to any one of the foregoing aspects, wherein the composition is single-phase.

[0149] 29. An injection-molded article comprising the α-nucleated propylene-ethylene random copolymer composition described in any one of aspects 1 to 28.

[0150] 30. The article of claim 29, wherein the article comprises the α-nucleated propylene-ethylene random copolymer composition of any one of claims 1 to 28.

[0151] 31. The article of manufacture according to aspect 29 or 30, wherein the article of manufacture is a thin-walled packaging container or various automotive parts, such as automotive interior parts, engine housings or automotive exterior parts.

[0152] Measurement method:

[0153] melt flow rate

[0154] Melt flow rate (MFR) is determined according to ISO 1133, with units of g / 10 min. MFR is an indicator of the polymer's flowability and therefore its processability. A higher melt flow rate generally corresponds to a lower polymer viscosity. The MFR² of polypropylene was measured at 230°C and a load of 2.16 kg.

[0155] Room temperature xylene solubles (XS, wt%)

[0156] The amount of polymer soluble in xylene was determined at 25°C according to ISO 16152 (5th edition, 2005-07-01).

[0157] DSC analysis, melting temperature (T) m ) and enthalpy of fusion (H f ), crystallization temperature (T) c ) and heat of crystallization (H c ): Samples of 5 to 7 mg were measured using a TA Instruments Q200 differential scanning calorimeter (DSC). The DSC was operated according to ISO 11357 / Part 3 / Method C2 in a heating / cooling / heating cycle at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C. Crystallization temperature (T c ) and enthalpy of crystallization (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.

[0158] Flexural modulus

[0159] Bending properties were determined according to ISO 178 Method A (three-point bending test) on an 80 mm × 10 mm × 4 mm specimen. Following this standard, a test speed of 2 mm / min and a span of 16 times the thickness were used. The test temperature was 23 ± 2 °C. Injection molding was performed according to ISO 19069-2 using a melt temperature of 200 °C for all materials, regardless of the melt flow rate.

[0160] Tensile modulus, tensile strength, tensile stress

[0161] Tensile properties were determined on injection-molded dog-bone shaped specimens prepared according to ISO 527-2. Tensile modulus was determined according to ISO 527-1 and ISO 527-2 at a tensile speed of 1 mm / min and a temperature of 23°C. Yield stress and yield strain were determined at a speed of 50 mm / min.

[0162] Notched impact strength (NIS)

[0163] Charpy notched impact strength (NIS) according to ISO 1791eA at +23°C, for use with 80×10×4 mm steel prepared according to ISO 19069-2. 3 Measurements were taken from injection-molded rod samples, using a melting temperature of 200°C for all materials, regardless of the material's melt flow rate.

[0164] Number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (MWD)

[0165] The molecular weight average (Mw, Mn) and molecular weight distribution (MWD), i.e., Mw / Mn (where Mn is the number-average molecular weight and Mw is the weight-average molecular weight), were measured by gel permeation chromatography (GPC) according to ISO 16014-4:2003 and ASTM D 6474-99. A PolymerChar GPC instrument equipped with an infrared (IR) detector was used with 3x Olexis and 1x Olexis Guard columns from Polymer Laboratories, with 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) as the solvent, at a constant flow rate of 1 mL / min at 160 °C. 200 μL of sample solution was injected for each analysis. The column was calibrated using a universal calibration method (according to ISO 16014-2:2003) with polystyrene (PS) standards ranging from 0.5 kg / mol to 11,500 kg / mol and narrow MWDs of at least 15. The Mark-Houwink constants for PS, PE, and PP were described according to ASTM D 6474-99. All samples were prepared as follows: 5.0–9.0 mg of polymer was dissolved in 8 mL (at 160 °C) of stabilized TCB (same as the mobile phase) with continuous gentle shaking in the autosampler of the GPC instrument at a maximum temperature of 160 °C for 2.5 h for PP and 3 h for PE.

[0166] Quantitative analysis of microstructure using NMR spectroscopy

[0167] Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the comonomer content and comonomer sequence distribution of polymers. It is employed using methods tailored to specific applications. 1 H and 13 A Bruker Advance III 400 NMR spectrometer, operating at 400.15 MHz and 100.62 MHz respectively, recorded quantitative data in solution. 13 C{ 1 H⁺ NMR spectroscopy. Using... 13 A C-optimized 10 mm extended temperature probe was used to record all spectra at 125 °C, and nitrogen was used for all pneumatic devices. Approximately 200 mg of sample was dissolved in 3 ml of [unspecified solution]. 1,2 -Tetrachloroethane- d 2 (TCE- d 2The sample was mixed with chromium acetylacetone (Cr(acac)3) to obtain a 65 mM relaxant solution dissolved in the solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure solution homogeneity, after initial sample preparation in a heating block, the NMR tube was further heated in a rotary furnace for at least 1 hour. The tube was then inserted into a magnet and rotated at 10 Hz. This setup was chosen primarily for the high resolution and accurate quantification requirements of ethylene content. Standard single-pulse excitation without NOE was employed, along with optimized tip angle, 1-second cyclic delay, and a dual-level 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 (6 kJ) transient signals were acquired for each spectrum.

[0168] Using proprietary computer programs for quantitative analysis 13 C{ 1 The ¹H NMR spectra were processed, integrated, and the relevant quantitative characteristics were determined based on the integration. All chemical shifts were indirectly referenced to the central methylene group (30.00 ppm) of the ethylene block (EEE) using the chemical shift of the solvent. This method allows for comparable references even in the absence of this structural unit. Characteristic signals corresponding to ethylene incorporation were observed (Cheng, HN, Macromolecules 17 (1984), 1950).

[0169] For polypropylene homopolymers, all chemical shifts are internally referenced to the methyl isotactic pentatonic group (mmmm) at 21.85 ppm.

[0170] Characteristic signals corresponding to regional defects were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, HN, Macromolecules 17 (1984), 1950) or comonomers.

[0171] The stereoregularity distribution was quantified by integrating the methyl region between 23.6 and 19.7 ppm and correcting for arbitrary sites unrelated to the target stereo sequence (Busico, V., Cipullo, R., Prog. Polym. Sci. 26(2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromoleucles 30 (1997) 6251).

[0172] Specifically, the influence of regional defects and comonomers on the quantitative distribution of stereoregularity is corrected by subtracting representative regional defects and comonomer integrals from specific integral regions of the stereo sequence.

[0173] Isothelic regularity was determined at the quintet level and reported as the percentage of isothelic quintet (mmmm) sequences out of all quintet sequences:

[0174]

[0175] The presence of two methyl sites at 17.7 ppm and 17.2 ppm indicates the presence of a 2,1-erythromorphic region defect, which was also confirmed by other characteristic sites.

[0176] No characteristic signals corresponding to other types of regional defects were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0177] The number of defects in the 2,1 erythromorph region was quantified using the average integral values ​​of two characteristic methyl sites at 17.7 ppm and 17.2 ppm:

[0178]

[0179] 1,2 The amount of primary inserted propene is quantified based on the methyl region, and corrections are made for sites included in this region that are unrelated to primary insertion, as well as primary insertion sites excluded from this region:

[0180]

[0181] The total amount of propylene is quantified as the sum of primary inserted propylene and all other existing regional defects:

[0182]

[0183] The molar percentage of defects in the 2,1 erythmic region was quantified relative to all propylene:

[0184]

[0185] For copolymers, characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, HN, Macromolecules 17 (1984), 1950).

[0186] Regional defects have also been observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, HN, Macromolecules 17 (1984), 1950), requiring correction for the effect of such defects on the comonomer content.

[0187] The comonomer fraction was determined using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33(2000), 1157) by analyzing... 13 C{ 1 Quantization is achieved by integrating multiple signals across the entire spectral region of the H spectrum. This method was chosen for its robustness and ability to handle regional defects when necessary. The integration region was slightly adjusted to improve applicability across the entire range of comonomer contents.

[0188] For systems where isolated ethylene is observed only in the PPEPP sequence, the method of Wang et al. was modified to reduce the influence of non-zero integrals from sites known to be absent. This method reduces the overestimation of ethylene content in such systems by reducing the number of sites used to determine the absolute ethylene content as follows:

[0189]

[0190] By using this set of sites, the corresponding integral equation becomes:

[0191]

[0192] The same notation as in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) was used. The formula for calculating the absolute content of propylene was not modified.

[0193] The molar percentage of comonomer incorporated is calculated from the mole fraction:

[0194]

[0195] The weight percentage of comonomer incorporated is calculated from the mole fraction:

[0196]

[0197] The distribution of comonomer sequences at the triplet level was determined using the analytical method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen because of its robustness and because a slight adjustment to the integration region improves its applicability to a wider range of comonomer contents.

[0198] Calculate the comonomer content of the second propylene-ethylene random copolymer fraction (B):

[0199]

[0200] in

[0201] w(PP1) is the mass fraction [split wt%] of the first propylene-ethylene random copolymer fraction (A).

[0202] w(PP2) is the mass fraction [split wt%] of the second propylene-ethylene random copolymer fraction (B).

[0203] C2(PP1) is the comonomer content [wt%] of the first propylene-ethylene random copolymer fraction (A).

[0204] C2(R-PP) is the comonomer content [wt%] of the single-phase propylene-ethylene random copolymer composition (R-PP).

[0205] C2(PP2) is the calculated comonomer content [wt%] of the second propylene-ethylene random copolymer fraction (B).

[0206] Heat distortion temperature (HDT):

[0207] The heat distortion temperature is 80×10×4 mm prepared according to ISO 19069-2. 3 Measurements were taken on injection-molded rod specimens, with a melt temperature of 200°C used for all materials, regardless of melt flow rate. The injection-molded specimens were placed in a heating bath. The specimens were then loaded onto a three-point bending device, aiming to achieve an external fiber stress of 0.45 MPa or 1.82 MPa. The bath temperature was increased at a constant rate of 120°C / h until the external fiber strain reached 0.2%. The temperature at which this degree of deformation was achieved is the material's heat distortion temperature.

[0208] Helical flow characteristics

[0209] The spiral test was performed using an Engel VC330 / 60 cc154 injection molding machine equipped with a spiral mold, at a pressure of 600, 1000 or 1400 bar.

[0210] Screw diameter: 35 mm

[0211] Maximum displacement: 154 cm 3

[0212] Injection pressure: 600, 1000, or 1400 bar

[0213] Tool shape: Oval; provided by Axxicon; thickness: 1 mm, width: 5 mm

[0214] Temperature of the preheating chamber and die head: 230℃

[0215] Temperatures in Zone 1 / Zone 2 / Zone 3 / Zone 4 / Zone 5: 230℃ / 230℃ / 230℃ / 225℃ / 200℃

[0216] Melting temperature: 220℃

[0217] Injection cycle: Injection time including hold: 10 seconds

[0218] Cooldown: 15 seconds

[0219] Injection pressure: Determined based on the predetermined length of the test material.

[0220] Holding pressure = Injection pressure

[0221] Screw speed: 30 rpm

[0222] System pressure: 10 bar

[0223] Metering path: The metering path should be selected so that the screw stops 20 mm before its final position at the end of the pressure holding period.

[0224] Tool temperature: 40℃

[0225] The spiral flow length can be measured immediately after the injection operation.

[0226] The haze is prepared according to ASTM D1003-07, with dimensions of 60×60×0.5mm, at 220°C according to ISO 19069-2. 3 60×60×1 mm 3 Or 60×60×2 mm 3 The measurements were taken on the injection-molded plate.

[0227] The gloss level is in accordance with ISO 2813. The sample is an injection-molded sheet with dimensions of 60×60×1 mm, manufactured according to ISO 19069-2 at 220°C. 3 The measurements were taken on the plate.

[0228] Yellowness Index

[0229] The yellowness index was determined according to ASTM E313. The board used had dimensions of 60×60×2 mm. 3 It is manufactured at 220°C in accordance with ISO 19069-2.

[0230] Top load

[0231] Compression tests for measuring the stiffness of injection-molded containers were conducted on a Zwick tensile testing machine at a speed of 10 mm / min, following the standard test method ASTM 2659-95. The rectangular box used had dimensions of 145 × 95 × 50 mm. 3 With a wall thickness of 0.5 mm, it is used to measure the top load (N) until the container collapses.

[0232] Cycle time measurement

[0233] We used Netstal SynErgy 1200-600, 45-23D, and cc286 injection molding equipment, equipped with different household container lids and household container box molds, to optimize cycle time.

[0234] Screw diameter: 45 mm

[0235] Maximum cylinder displacement: 286 cc

[0236] Tools used: Household container lid (size = 145×95×10 mm) 3 (0.5 mm thick) and household container box (dimensions = 145 × 95 × 50 mm)3 Mold with a thickness of 0.5 mm.

[0237] Temperature: Zone 1 / Zone 2 / Zone 3 / Zone 4 / Zone 5 / Feeding Zone: 220℃ / 220℃ / 220℃ / 220℃ / 190℃

[0238] Melting temperature: 220℃

[0239] Mold gate temperature: 200℃

[0240] Mold temperature: 50℃

[0241] Preparation of Examples

[0242] Compositions CE, IE1, and IE2 have been produced in a Borstar™ two-step polymerization process, starting in a prepolymerization reactor, followed by polymerization in a bulk-phase loop reactor, and then in a gas-phase reactor, with molecular weight and ethylene content varied by the feed of hydrogen and comonomers. The polymerization process uses a Ziegler-Natta catalyst with triethylaluminum (TEAL) as a cocatalyst and dicyclopentyldimethoxysilane (donor "D") as a donor.

[0243] The catalyst was produced as follows: First, under inert conditions, 0.1 mol of MgCl₂ × 3EtOH was suspended in 250 mL of decane at atmospheric pressure within a reactor. The solution was cooled to -15°C, and 300 mL of cold TiCl₄ was added while maintaining the temperature at this level. Then, the temperature of the slurry was slowly raised to 20°C. At this temperature, 0.02 mol of dioctyl phthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135°C over a period of 90 minutes, and the slurry was allowed to stand for 60 minutes. Then, another 300 mL of TiCl₄ was added, and the temperature was maintained at 135°C for 120 minutes. Afterward, the catalyst was filtered from the liquid and washed six times with 300 mL of heptane at 80°C. The solid catalyst component was then filtered and dried. The catalyst and its preparation concept are generally described in, for example, patent publications EP491566, EP591224, and EP586390. The ratio of aluminum to donor is shown in Table 1.

[0244] Prior to the prepolymerization of Examples IE1 and IE2, the catalyst was modified by prepolymerizing it with a certain amount of vinylcyclohexane to achieve a poly(vinylcyclohexane) (pVCH) concentration of 10 to 20 ppm in the final polymer. The relevant processes are described in EP1028984, EP1183307, and EP2960279. Prepolymerization with propylene was carried out in a stirred tank reactor in the liquid phase. Subsequently, the polymer was transferred to a loop reactor, where a first copolymer fraction (A) was prepared using the parameters in the corresponding section of Table 1. The polymer was then transferred again to a gas-phase reactor (GPR1) to prepare a second copolymer fraction (B) using the parameters in the corresponding section of Table 1.

[0245] Table 1: Aggregation Conditions

[0246]

[0247] As shown in Table 2, the additive combination of Irganox 1010 (pentaerythritol tetra(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, CAS No.: 6683-19-8), Irgafos 168 (tris(2,4-di-tert-butylphenyl)phosphate, CAS No.: 31570-04-4), calcium stearate (supplied by Croda Polymer Additives, CAS No.: 1592-23-0) and GMS95Tris (glyceryl monostearate) was used to compound the obtained PP powder.

[0248] Comparative compositions CE1-CE3 were obtained by further blending CE PP powder with BNT masterbatch (HC205TF, a polypropylene homopolymer nucleated with pVCH), without adding any other nucleating agents, NA21 (containing hydroxybis(2,4,8,10-tetratert-butyl-6-hydroxy-12H-dibenzo(d,g)(1,3,2)dioxaphosphorus octane 6-oxide) aluminum, CAS No.: 151841-65-5, purchased from ADEKA, Japan) or NA71 (containing 2,2'-methylenebis(4,6-ditert-butylphenyl) phosphate lithium salt, CAS No.: 85209-93-4, purchased from ADEKA, Japan).

[0249] Compositions IE1 and IE2 are obtained by blending PP powders IE1 and IE2 with other nucleating agent HPN600ei (containing a calcium salt of cis-1,2-cyclohexanedicarboxylic acid and zinc stearate, supplied by Milliken).

[0250] Table 2: Weight percentage of additives and PP powder in the composition

[0251]

[0252] Table 3: Physical properties of the obtained composition

[0253]

[0254] The higher DSC crystallization temperatures in IE1 and IE2 indicate that they crystallize faster than in CE1. Examples of this invention report higher melting peaks (Tm) and crystallization temperatures (Tc).

[0255] Table 4: Mechanical and optical properties of the embodiments and comparative examples of the present invention

[0256]

[0257] Compared to CE1, IE1 and IE2 exhibit superior flexural modulus and tensile properties, significantly impacting the final molded product (while maintaining the same Charpy NIS value). Consequently, the top load-bearing capacity or load-bearing capacity of the injection-molded container is also higher, contributing to the stackability of the molded product. Compared to CE1-CE3, the embodiments of the present invention offer a superior balance of stiffness (tensile modulus) and Charpy impact (NIS), demonstrated by a higher ratio of tensile modulus to Charpy notched impact strength (NIS). The mechanical properties of the embodiments of the present invention are also advantageous in situations requiring the containment of contents (e.g., food) and sufficient stiffness for stacking. Finally, these materials also withstand mechanical impact damage, such as the damage often seen in dropped products. In the fields of thin-walled packaging and / or large automotive components, high tensile modulus and good impact strength (i.e., superior...) are highly desirable. Materials with good flowability (high MFR) are crucial.

[0258] IE1 and IE2 also exhibit excellent transparency because pVCH (NU1) and HPN600ei (NU2) together provide faster grain growth. The 1 mm or 2 mm molded samples of IE1 and IE2 in the embodiments of the present invention also showed low haze values ​​and slightly higher gloss values. Improved transparency was observed in the embodiments of the present invention using a combination of 1.2 wt% C2 content, pVCH (NU1), and HPN600ei (NU2).

[0259] The resulting polypropylene composition is molded into an article.

[0260] Table 5: Cycle time test results for embodiments and comparative examples of the present invention

[0261]

[0262] Depending on the shape and size of the molded product, the optimized cycle time of the finished container in the embodiments of the present invention is better. For thin-walled packaging containers or various automotive parts, such as automotive interior parts, engine housings, automotive exterior parts, etc., the optimized cycle time can vary from 5% to 10%.

[0263] Table 6 below shows that the embodiments and comparative examples of the present invention demonstrate significantly improved processing performance (flowability) by testing the spiral flow of 1 mm thick samples at a melting temperature of 220°C (the test was repeated five times and the average value is given).

[0264] Table 6: Flowability of Embodiments and Comparative Examples of the Invention

[0265]

[0266] The good flowability of the embodiments of the present invention, together with suitable additives, has been shown to enable good processing performance in various article manufacturing methods (e.g., injection molding processes), thereby allowing for the high production speeds and shorter cycle times required by the mass production market.

Claims

1. A random copolymer composition of α-nucleated propylene and ethylene, wherein, The α-nucleating propylene-ethylene random copolymer composition comprises: a) A single-phase propylene-ethylene random copolymer (R-PP), wherein the single-phase propylene-ethylene random copolymer (R-PP) has the following characteristics: - Based on the total weight of the single-phase propylene-ethylene random copolymer, through 13 The ethylene content (C2) determined by C-NMR spectroscopy is 0.5 to 5.0 wt%, more preferably 0.6 to 4.0 wt%, and most preferably 0.6 to 2.5 wt%. - The melt flow rate MFR2 (230°C) measured according to ISO 1133 is 20 to 500 g / 10 min, preferably 30 to 300 g / 10 min, more preferably 35 to 200 g / 10 min; and b) At least two nucleating agents (NU), wherein: - One of the at least two nucleating agents is a vinylcycloalkane polymer (NU1), preferably poly(vinylcyclopentane) or poly(vinylcyclohexane) (pVCH), more preferably poly(vinylcyclohexane) (pVCH); - Another of the at least two nucleating agents (NU2) comprises a salt of bridged or non-bridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib): ， In the formula, x is 1 or 2, y is 1 or 2, and x For y=2, M is an alkali metal; for y=1, M is an alkaline earth metal; R 1 To R 10 Independently, it is a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 9 carbon atoms, an amino group, an alkylamine group having 1 to 9 carbon atoms, a halogen atom, a phenyl group, or a group of the formula R-(R'-O). n - indicates a group, where R is an alkyl group having 1 to 3 carbon atoms, R' is an alkylene group having 2 or 3 carbon atoms, and n is an integer from 1 to 4; and R 1 To R 10 Any two alkyl groups can be linked together to form a carbon ring with 3 to 6 carbon atoms.

2. The α-nucleating propylene-ethylene random copolymer composition according to claim 1, wherein, The single-phase propylene-ethylene random copolymer (R-PP) is quantitatively... 13 The 2,1- region defects measured by C-NMR were less than 0.4 mol.

3. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, Based on the total weight of the nucleating agent (NU2), the nucleating agent (NU2) contains ≥50 wt% of a salt of bridged or non-bridged cyclohexanedicarboxylic acid of formula (Ia) or (Ib); and / or the salt of bridged or non-bridged cyclohexanedicarboxylic acid of formula (Ia) or (Ib) is a calcium salt of cis-1,2-cyclohexanedicarboxylic acid.

4. The α-nucleating propylene-ethylene random copolymer composition according to claim 1 or 2, wherein, The single-phase propylene-ethylene random copolymer (R-PP) is a multi-peaked, preferably bi-peaked, propylene-ethylene random copolymer (R-PP) with respect to ethylene content, and comprises at least two propylene-ethylene random copolymer fractions (A) and (B), wherein: - Based on the total weight of the propylene-ethylene random copolymer (R-PP), the total amount of the two propylene-ethylene random copolymer fractions (A) and (B) is at least 90 wt%; - The ethylene content of the first propylene-ethylene random copolymer fraction (A) is 0.1 to 1.5 wt%, more preferably 0.3 to 1.2 wt%, and the ethylene content of the second propylene-ethylene copolymer fraction (B) is 0.8 to 2.5 wt%, more preferably 1.0 to 2.0 wt%, and the ethylene content of the first propylene-ethylene random copolymer fraction (A) is lower than the ethylene content of the second propylene-ethylene copolymer fraction (B). The ethylene content of the first propylene-ethylene random copolymer fraction (A) is preferably at least 0.2 wt%, more preferably 0.2 to 2.0 wt%, and even more preferably 0.3 to 1.5 wt% lower than the ethylene content of the second propylene-ethylene copolymer fraction (B). - The weight ratio between the first propylene-ethylene copolymer fraction (A) and the second propylene-ethylene copolymer fraction (B) is 40:60 to 60:

40.

5. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The propylene-ethylene random copolymer (R-PP) is non-viscosity-reducing cracked, preferably a reactor-prepared propylene-ethylene random copolymer; and / or the propylene-ethylene random copolymer (R-PP) does not contain peroxides or peroxide decomposition products.

6. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The propylene-ethylene random copolymer (R-PP) has the following characteristics: - The molecular weight distribution (MWD) determined by gel permeation chromatography according to ISO 16014-4:2003 and ASTM D 6474-99 is at least 5.0, preferably 6.0 to 10.0; and / or - The xylene soluble content (XS) measured at 25°C according to ISO 16152 is less than 4.0 wt%, preferably 0.5 to 3.5 wt%, more preferably 1.0 to 3.0 wt%, and most preferably 1.5 to 2.7 wt%.

7. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein: - Based on the total weight of the propylene-ethylene random copolymer composition, the content of the vinyl cycloalkane polymer (NU1) is 0.1-2000 ppm, preferably 1.0-1000 ppm; and / or - Based on the total weight of the propylene-ethylene random copolymer composition, the nucleating agent (NU2) comprising the salt of bridged or unbridged cyclohexanedicarboxylic acid as shown in formula (Ia) or (Ib) is 20-1000 ppm, preferably 50-500 ppm.

8. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The composition does not contain any nucleating agents other than the vinyl cycloalkane polymer (NU1) and the nucleating agent (NU2) containing the salt of bridging or non-bridging cyclohexane dicarboxylic acid as shown in formula (Ia) or (Ib).

9. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, Based on the total weight of the propylene-ethylene random copolymer composition, the content of the propylene-ethylene random copolymer (R-PP) is greater than 85 wt%, preferably 90 to 99.9 wt%, and more preferably 95 to 99.9 wt%.

10. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, Based on the total weight of the propylene-ethylene random copolymer composition, the total amount of the propylene-ethylene random copolymer (R-PP) and at least two nucleating agents (NU) is greater than 90 wt%, preferably 95.0 to 99.9 wt%, and more preferably 97.0 to 99.9 wt%.

11. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The composition has the following properties: - The melt flow rate MFR2 (230°C), measured according to ISO 1133, is 20 to 500 g / 10 min, preferably 30 to 300 g / 10 min; and - The xylene soluble content (XS) measured at 25°C according to ISO 16152 is less than 4 wt%.

12. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The composition has the following properties: - The crystallization temperature Tc, measured by differential scanning calorimetry (DSC), is at least 123°C, preferably 124°C to 135°C, more preferably 125°C to 130°C; and / or - The melting temperature Tm, measured by differential scanning calorimetry (DSC), is at least 153°C, more preferably 153°C to 170°C; and / or - 80×10×4 mm prepared according to ISO 19069-2 3 The heat distortion temperature (HDT) measured on the injection-molded bar sample at a melting temperature of 200°C is greater than 110°C, preferably 110°C to 130°C, and most preferably 112°C to 125°C.

13. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The composition has the following properties: - The tensile modulus, measured according to ISO 527-1,-2 at 1 mm / min and 23°C, is greater than 1800 MPa, preferably between 1800 MPa and 2200 MPa; and - 80×10×4 mm injection molded according to ISO 19069-2, in accordance with ISO 179. 3 The ratio of the tensile modulus to the Charpy notched impact strength (NIS) of the test bar measured at 23°C satisfies equation (a): 。 14. The α-nucleating propylene-ethylene random copolymer composition according to any one of the preceding claims, wherein, The composition has the following properties: - According to ASTM D1003-07, the dimensions are 60×60×1 mm. 3 The haze value measured on the plate is less than 70%, preferably less than 65%; and / or - According to ASTM E313, the dimensions are 60×60×2 mm. 3 The yellowness index measured on the plate is less than or equal to 6.0, preferably 0.1 to less than 6.0, and more preferably 0.1 to 5.

5.

15. An injection-molded article, wherein, The injection-molded article comprises the α-nucleated propylene-ethylene random copolymer composition according to any one of claims 1 to 14, preferably composed of the α-nucleated propylene-ethylene random copolymer composition according to any one of claims 1 to 14, and the article is preferably a thin-walled packaging container or automotive part, such as automotive interior parts, engine housings or automotive exterior parts.

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