Propylene composition with improved sealing and barrier properties

Abstract

The present invention relates to a polypropylene composition comprising: a) a homopolymer of propylene in an amount of 95 to 100 wt%, based on the total weight of the polypropylene composition, and b) optionally an additive in an amount of 0 to 5 wt%, based on the total weight of the polypropylene composition; wherein the polypropylene composition has: a melt flow rate MFR2, determined according to ISO 1133 at 230 DEG C under a load of 2.16 kg, of 2.5 to 12.0 g / 10 min; from 0.1 to 1.8 wt% of a xylene cold soluble (XCS) content, determined according to ISO 16152; from 0 to 0.5 wt% of an ethylene content as determined by 13C-NMR spectroscopy; a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), Mw / Mn, determined according to the GPC method described herein, of 4.5 to 9.0, preferably 5.0 to 8.0; a melting temperature Tm of 160 to 175 DEG C as determined according to ISO 11357 / Part 3 / Method C2; and a crystallization temperature Tc of 122 to 135 DEG C as determined according to ISO 11357 / Part 3 / Method C2.

Description

Technical Field

[0001] This invention relates to a polypropylene composition comprising a homopolymer of propylene and optionally additives. The invention further relates to a method for obtaining such a composition, an article comprising such a composition, and the use of such an article in pharmaceutical packaging. Background Technology

[0002] In response to current industry needs and trends, pharmaceutical packaging is increasingly focused on providing easily recyclable packaging for products. Specifically, pharmaceutical blister packaging has received particular attention in Europe in recent years because many blister packs use polyvinyl chloride (PVC), polyvinylidene chloride (PvDC), or fluoropolymers for their sides, while the push-through closure is made of aluminum, which significantly hinders mechanical recycling. Although these structures have been on the market for many years, they haven't truly achieved an ideal design; for example, there are problems with the seal between the aluminum layer and the PVC base layer. To enhance the seal, an additional sealant layer must be present between these two layers; this ultimately complicates recycling and increases production costs. Furthermore, PVC's limited moisture barrier properties (or moisture resistance) also make it a less attractive material for pharmaceutical blister packaging, as protecting the contents from contamination becomes challenging.

[0003] Various solutions for blister packaging, focusing on improving different properties, have been extensively studied in this field. For example, US 2020 / 0399037 A1 discloses a multilayer structure suitable for blister packaging applications. This document aims to address moisture permeation issues related to blister packaging materials and discloses a multilayer structure comprising, in that order, a first polymer layer, which may be metallized polyethylene terephthalate (PET); a first connecting layer, which may be an adhesive varnish; a second polymer layer, which may be a homopolymer of cycloolefin or trifluorochloroethylene; a second connecting layer, which may be an adhesive varnish; and a third polymer layer, which may contain polypropylene or PVC. However, such structures inevitably present problems during mechanical recycling, and their production requires lamination methods, making the final product significantly more expensive.

[0004] On the other hand, document EP 0570188 B2 discloses the use of sheets as blister packs or compression packs (PTP) and aims to address issues related to moisture barrier properties. However, this blister pack or PTP comprises a layer made of at least one amorphous polyolefin resin (a cyclic olefin copolymer) and possibly a crystalline polyolefin resin (having a crystallinity greater than 10% as determined by X-ray diffraction). While the corresponding sheets exhibit high moisture barrier properties, their thermal stability is limited by the low glass transition temperature of the amorphous polyolefin used.

[0005] Therefore, there remains a need to obtain polymer-based films exhibiting improved mechanical, optical, barrier, and sealing properties. This invention addresses the aforementioned problems and achieves the aforementioned improved properties through the polymer compositions disclosed herein. Summary of the Invention

[0006] This invention relates to a polypropylene composition comprising:

[0007] a) Based on the total weight of the polypropylene composition, a homopolymer of propylene comprising 95 to 100% by weight, and

[0008] b) Optionally, based on the total weight of the polypropylene composition, an amount of 0 to 5% by weight of additives;

[0009] The polypropylene composition has the following characteristics:

[0010] Melt flow rate MFR2, measured according to ISO 1133 at 230 °C and under a load of 2.16 kg, from -2.5 to 12.0 g / 10 min;

[0011] -0.1 to 1.8% by weight of xylene cold solubles (XCS) content as determined according to ISO 16152;

[0012] -0 to 0.5% by weight of 13 Ethylene content determined by C-NMR spectroscopy;

[0013] The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) as determined by the GPC method described herein is -4.5 to 9.0, preferably 5.0 to 8.0;

[0014] The melting temperature Tm, determined according to ISO 11357 / Part 3 / Method C2, ranging from -160 to 175°C; and

[0015] The crystallization temperature Tc, determined according to ISO 11357 / Part 3 / Method C2, is between -122 and 135 °C.

[0016] The present invention further relates to a method for obtaining a polypropylene composition as described herein, using a multi-stage polymerization method, comprising the following steps:

[0017] a) In the first polymerization reactor (R1), propylene is polymerized in the presence of a Ziegler-Natta catalyst to obtain a first polymerization product;

[0018] b) Transfer the first polymerization product to the second polymerization reactor (R2) and obtain the final polymerization product; and

[0019] c) Optionally, the final polymerization product obtained in step b) is blended with the additive.

[0020] The present invention further relates to an article, preferably a film, comprising a polypropylene composition as described herein.

[0021] The present invention further relates to the use of the articles described herein in pharmaceutical packaging. Detailed Implementation Plan

[0022] All terms used herein are to be understood in their conventional meanings as commonly known to those skilled in the art.

[0023] Polypropylene composition

[0024] The present invention relates to a polypropylene composition comprising a homopolymer of polypropylene and optionally additives, wherein the amount of the homopolymer of polypropylene is 95 to 100 wt%, preferably 97 to 100 wt%, more preferably 98.5 to 100 wt%, based on the total weight of the polypropylene composition, and the amount of the additives is 0 to 5 wt%, preferably 0 to 3 wt%, more preferably 0 to 1.5 wt%.

[0025] The polypropylene composition according to the invention has a melt flow rate (MFR2) of 2.5 to 12.0 g / 10 min, determined according to ISO 1133 at 230°C and a load of 2.16 kg. The preferred melt flow rate (MFR2) of the polypropylene composition, determined according to ISO 1133 at 230°C and a load of 2.16 kg, ranges from 3.0 to 8.0 g / 10 min, more preferably from 4.0 to 7.0 g / 10 min.

[0026] The polypropylene composition according to the invention further has a xylene cold solubles (XCS) content of 0.1 to 1.8% by weight, preferably 0.2 to 1.5% by weight, more preferably 0.5 to 1.5% by weight, as determined according to ISO 16152. Particularly preferred is that the polypropylene composition has a melt flow rate (MFR2) of 3.0 to 8.0 g / 10 min, more preferably 4.0 to 7.0 g / 10 min, as determined according to ISO 1133 at 230°C and a load of 2.16 kg, and a xylene cold solubles (XCS) content of 0.2 to 1.5% by weight, more preferably 0.5 to 1.5% by weight, as determined according to ISO 16152.

[0027] Further, the polypropylene composition according to the invention has 0 to 0.5% by weight, preferably 0 to 0.3% by weight, more preferably 0 to 0.2% by weight of [the polypropylene composition]. 13 Ethylene content determined by C-NMR spectroscopy.

[0028] Furthermore, the polypropylene composition of the present invention has a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of 4.5 to 9.0, preferably 5.0 to 8.0, as determined by the GPC method described herein, in the form of Mw / Mn.

[0029] The polypropylene compositions of the present invention as described herein have a melt temperature Tm of 160 to 175°C, preferably 165 to 170°C, as determined according to ISO 11357 / Part 3 / Method C2. Additionally, the polypropylene compositions have a crystallization temperature Tc of 122 to 135°C, preferably 125 to 130°C, as determined according to ISO 11357 / Part 3 / Method C2.

[0030] Preferably, the polypropylene compositions described herein are not subjected to viscosity-reducing cracking, meaning they are prepared directly in the reactor sequence and are not subject to controlled degradation induced by free radicals. Non-viscosity-reducing cracked polypropylene compositions are characterized by a broad molecular weight distribution, the absence of decomposition products from peroxides or other free radical-generating compounds, and fewer emissions. This is also reflected in the fact that the polypropylene compositions described herein are preferably characterized by a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio (Mw / Mn) determined by GPC methods in the range of 4.5 to 9.0, more preferably in the range of 5.0 to 8.0.

[0031] In a preferred embodiment, the polypropylene composition according to the invention has a longitudinal tensile modulus of 900 to 1900 MPa, more preferably 1100 to 1800 MPa, and most preferably 1500 to 1700 MPa, as determined according to ISO 527-3 on a 300 µm cast film.

[0032] It is also preferred that the polypropylene composition has a haze value of 0 to 40%, more preferably 0 to 35%, and most preferably 0 to 30% on a 300 µm cast film as determined by ASTM D1003; and / or 20 to 100%, more preferably 50 to 90%, and most preferably 60 to 80% on a 300 µm cast film as determined by wide-angle X-ray scattering (WAXS). This haze value is particularly preferred because a more transparent film allows for greater visibility of the contents in the blister pack; therefore, this haze range makes the polypropylene composition according to the invention advantageous for use in blister packs. On the other hand, crystallinity is an important parameter because it is related to the final stiffness of the article made from the polypropylene composition (which is one of the main mechanical properties studied for blister packs).

[0033] Further preferably, the polypropylene composition has a low water vapor transmission rate (WVTR) measured according to ISO 15106-3:2003 on a 300 µm cast film to keep the contents of the blister pack away from contaminants (in this case, water vapor), and the WVTR is preferably in the range of 0 to 1.0 g / m. 2 Days (g / m 2 (day), more preferably 0.1 to 0.8 g / m 2 Even more preferably, it is 0.1 to 0.6 g / m³. 2 The optimal concentration is 0.2 to 0.5 g / m³. 2 Similarly, it is further preferred that the polypropylene composition has a low oxygen transmission rate (OTR) on a 300 µm cast film, as determined according to ASTM D 3985, ranging from 50 to 300 cm⁻¹. 3 / m 2 Tianba (cm) 3 / m 2 (day bar), more preferably 80 to 260 cm 3 / m 2 Tenba, and the most preferred size is 100 to 200 cm. 3 / m 2 Tianba.

[0034] Further preferably, the polypropylene composition exhibits good sealing performance when sealed with the aluminum-based sheet for the push-through portion of blister packaging. Therefore, it is particularly preferred that the polypropylene composition according to the invention has a seal initiation temperature (SIT) of 140 to 160°C, more preferably 145 to 155°C, measured on a 300 µm cast film according to the procedure defined in this application. Further preferably, the polypropylene composition according to the invention has a sealing force of 4 to 15 N / cm, more preferably 4.5 to 10 N / cm, measured on a 300 µm cast film at 150°C according to the procedure defined in this application. Further preferably, the polypropylene composition according to the invention has a sealing force of 5 to 15 N / cm, more preferably 6 to 10 N / cm, measured on a 300 µm cast film at 180°C according to the procedure defined in this application.

[0035] method

[0036] The present invention further relates to a method for obtaining a polypropylene composition as described herein, using a multi-stage polymerization method, comprising the following steps:

[0037] a) In the first polymerization reactor (R1), propylene is polymerized in the presence of a Ziegler-Natta catalyst to obtain a first polymerization product;

[0038] b) Transfer the first polymerization product to the second polymerization reactor (R2) and obtain the final polymerization product; and

[0039] c) Optionally, the final polymerization product obtained in step b) is blended with the additive.

[0040] In a preferred embodiment, other steps are performed prior to step a) of the method described herein:

[0041] a0) In a prepolymerization reactor, the Ziegler-Natta catalyst is modified, preferably with a polymer nucleating agent, more preferably with a vinyl polymer, and propylene is prepolymerized.

[0042] The polymerization method of the polypropylene composition is carried out according to the multi-stage polymerization described above, preferably according to the sequential polymerization method. The term "sequential polymerization" indicates that the propylene homopolymer is prepared in at least two reactors connected in series. Therefore, this polymerization system includes at least the first polymerization reactor (R1) described in step a) and the second polymerization reactor (R2) described in step b). The term "polymerization reactor" should indicate that the main polymerization occurs. Therefore, in the case where this method consists of two polymerization reactors, this definition does not exclude the option that the entire system includes a prepolymerization step, for example, carried out in a prepolymerization reactor. The term "consisting of" is only a closed statement for the main polymerization reactor.

[0043] Preferably, at least one of the two polymerization reactors (R1) and (R2) is a gas-phase reactor (GPR). More preferably, the second polymerization reactor (R2) is a gas-phase reactor (GPR). The gas-phase reactor (GPR) according to the invention is preferably a fluidized bed reactor, a fast fluidized bed reactor, or a fixed bed reactor, or any combination thereof. Accordingly, the first polymerization reactor (R1) is preferably a slurry reactor (SR) and can be any continuous or simply stirred batch reactor or loop reactor operating in bulk or slurry. Bulk refers to polymerization in a reaction medium containing at least 60% (w / w) monomer. According to the invention, the slurry reactor (SR) is preferably a (bulk) loop reactor (LR).

[0044] Preferably, the propylene homopolymer from the first polymerization reactor (R1) (i.e., the fraction prepared in the polymer slurry of the first polymerization reactor (R1), more preferably in the loop reactor (LR)) is directly fed to the second polymerization reactor (R2), i.e., to the (first) gas-phase reactor (GPR1), without the need for a flash evaporation step between stages. This direct feeding is described in EP 887379A, EP 887380 A, EP 887381 A and EP 991684 A. "Direct feeding" refers to the method of directly introducing the contents of the first polymerization reactor (R1) (i.e., the loop reactor (LR)) (a polymer slurry containing the first propylene homopolymer fraction (H-PP1)) into the next stage gas-phase reactor.

[0045] Alternatively, the propylene homopolymer from the first polymerization reactor (R1) (i.e., the fraction prepared in the first polymerization reactor (R1)) can also be directed to a flash evaporation step or undergo a further concentration step before being fed to the second polymerization reactor (R2) (i.e., the gas phase reactor (GPR)). Accordingly, this "indirect feed" refers to the method of feeding the contents (i.e., polymer slurry) of the first polymerization reactor (R1) (loop reactor (LR)) to the second polymerization reactor (R2) ((first) gas phase reactor (GPR1)) through a reaction medium separation unit, with the reaction medium originating as a gas from the separation unit.

[0046] More specifically, the second polymerization reactor (R2) can be any mechanically mixed reactor or fluidized bed reactor. Preferably, the gas-phase reactor (GPR) comprises a mechanically stirred fluidized bed reactor with a gas flow rate of at least 0.2 m / s. Therefore, it should be understood that the gas-phase reactor is preferably a fluidized bed reactor with a mechanical stirrer.

[0047] Therefore, in a preferred embodiment, the first polymerization reactor (R1) is a slurry reactor (SR), such as a loop reactor (LR), while the second polymerization reactor (R2) is a gas-phase reactor (GPR). Thus, for this method, two polymerization reactors (R1) and (R2) are used in series, namely the slurry reactor (SR) (such as a loop reactor (LR)) and the (first) gas-phase reactor (GPR1). If necessary, a pre-polymerization reactor is placed before the slurry reactor (SR).

[0048] The Ziegler-Natta catalyst (ZN-C) is fed into the first polymerization reactor (R1) and transferred together with the polymer (slurry) obtained in the first polymerization reactor (R1) to a subsequent reactor. If the method further includes a prepolymerization step, it is preferable to feed all of the Ziegler-Natta catalyst (ZN-C) into the prepolymerization reactor. The prepolymer product containing the Ziegler-Natta catalyst (ZN-C) is then transferred to the first polymerization reactor (R1).

[0049] Preferred multi-stage methods include the "loop-gas phase" method (called BORSTAR® technology) developed by Borealis A / S of Denmark, as described in patent documents such as EP 0 887 379, WO 92 / 12182, WO2004 / 000899, WO 2004 / 111095, WO 99 / 24478, WO 99 / 24479, or WO 00 / 68315. Other suitable slurry-gas phase methods include Basell's Spheripol. ® method.

[0050] Careful selection of the temperature in the reactor can achieve particularly excellent results.

[0051] Therefore, the operating temperature in the first polymerization reactor (R1) is preferably in the range of 62 to 90°C, more preferably in the range of 70 to 88°C, and even more preferably in the range of 75 to 85°C.

[0052] Alternatively or otherwise, the operating temperature in the second polymerization reactor (R2) is preferably in the range of 62 to 90°C, more preferably in the range of 70 to 88°C, and even more preferably in the range of 75 to 85°C.

[0053] Typically, the pressure in the first polymerization reactor (R1), preferably a loop reactor (LR), is in the range of 2000 to 8000 kPa, more preferably in the range of 3000 to 7000 kPa, for example in the range of 3500 to 6500 kPa, while the pressure in the second polymerization reactor (R2), i.e. the (first) gas phase reactor (GPR1), is in the range of 500 to 5000 kPa, more preferably in the range of 1500 to 4000 kPa.

[0054] Hydrogen is preferably added to each polymerization reactor to control the molecular weight, i.e., to control the melt flow rate MFR2.

[0055] Preferably, the average residence time in polymerization reactors (R1) and (R2) is relatively long. Generally, the average residence time (τ) is defined as the reaction volume (V). R ) and the reactor volumetric outflow rate (Q) o The ratio of V to V R / Q o ), that is, τ=V R / Q o [tau=V R / Q o In the case of a loop reactor, the reaction volume (V) R () equals the reactor volume.

[0056] Therefore, the average residence time (τ) in the first polymerization reactor (R1) is preferably at least 15 min, more preferably in the range of 15 to 80 min, even more preferably in the range of 20 to 60 min, for example in the range of 24 to 50 min, and / or the average residence time (τ) in the second polymerization reactor (R2) is preferably at least 70 min, more preferably in the range of 70 to 220 min, even more preferably in the range of 80 to 210 min, and even more preferably in the range of 90 to 200 min, for example in the range of 90 to 190 min.

[0057] Polypropylene (Pre-PP) is prepared in a prepolymerization reactor (PR). Prepolymerization is carried out in the presence of a Ziegler-Natta catalyst (ZN-C). According to this embodiment, the Ziegler-Natta catalyst (ZN-C), cocatalyst (Co), and external donor (ED) are all introduced into the prepolymerization step. However, this does not preclude the option of adding, for example, other cocatalysts (Co) and / or external donors (ED) to the polymerization process in subsequent stages, such as to the first reactor (R1). In one embodiment, if prepolymerization is applied, the Ziegler-Natta catalyst (ZN-C), cocatalyst (Co), and external donor (ED) are only added to the prepolymerization reactor (PR).

[0058] The prepolymerization reaction is typically carried out at temperatures of 0 to 60°C, preferably 15 to 50°C, and more preferably 20 to 45°C.

[0059] The pressure in the prepolymerization reactor is not critical, but it needs to be high enough to keep the reaction mixture in the liquid phase. Therefore, the pressure can be between 2000 and 8000 kPa, for example, 2200 to 7000 kPa.

[0060] In a preferred embodiment, the prepolymerization reaction is carried out in liquid propylene via bulk slurry polymerization, i.e., the liquid phase mainly comprises propylene, wherein an inert component may optionally be dissolved. Furthermore, according to the invention, ethylene is used as feedstock during the prepolymerization process as described above.

[0061] Other components may also be added during the prepolymerization stage. Therefore, as is known in the art, hydrogen can be added during the prepolymerization stage to control the molecular weight of polypropylene (Pre-PP). Furthermore, antistatic additives can be used to prevent particles from adhering to each other or to the reactor walls.

[0062] Precise control of prepolymerization conditions and reaction parameters is within the scope of this technology.

[0063] Due to the method conditions in the prepolymerization process defined above, it is preferable to obtain a mixture (MI) of Ziegler-Natta catalyst (ZN-C) and polypropylene (Pre-PP) produced in the prepolymerization reactor (PR). Preferably, the Ziegler-Natta catalyst (ZN-C) is (goodly) dispersed in the polypropylene (Pre-PP). In other words, the Ziegler-Natta catalyst (ZN-C) particles introduced into the prepolymerization reactor (PR) break down into smaller fragments, which are uniformly distributed in the grown polypropylene (Pre-PP). The size of the introduced Ziegler-Natta catalyst (ZN-C) particles and the size of the resulting fragments are not substantially relevant to the present invention and are within the knowledge of those skilled in the art.

[0064] As mentioned above, if prepolymerization is used, the mixture (MI) of Ziegler-Natta catalyst (ZN-C) and polypropylene (Pre-PP) produced in the prepolymerization reactor (PR) is transferred to the first reactor (R1) after the prepolymerization. Typically, the total amount of polypropylene (Pre-PP) in the final propylene copolymer (R-PP) is quite low and generally does not exceed 5.0% by weight, more preferably not more than 4.0% by weight, and even more preferably in the range of 0.5% to 4.0% by weight, such as in the range of 1.0% to 3.0% by weight.

[0065] As mentioned above, the Ziegler-Natta catalyst (ZN-C) can be modified in the prepolymerization step a0). Details of this modification will be provided below.

[0066] catalyst

[0067] In a preferred embodiment, the catalyst is a solid Ziegler-Natta catalyst, comprising:

[0068] a) Compounds of IUPAC group 4 to 6 transition metals;

[0069] b) IUPAC Group 2 metal compounds;

[0070] c) Internal donors, i.e., non-phthalic acid compounds, preferably non-phthalic acid esters;

[0071] d) co-catalysts; and

[0072] e) Optionally, an external donor.

[0073] The catalyst comprises a compound of a Group 4 to 6 transition metal (e.g., titanium) of IUPAC (TC), a compound of a Group 2 metal (e.g., magnesium) (MC), and an internal donor (ID). The internal donor (ID) is a non-phthalic acid compound, preferably a non-phthalic ester, and more preferably a dieter of non-phthalic dicarboxylicacids, as described in more detail below. Therefore, in a preferred embodiment, the catalyst is completely free of undesirable phthalic acid compounds. Furthermore, the solid catalyst does not contain any external support material, such as silica or MgCl2, and is a self-supported catalyst.

[0074] The Ziegler-Natta catalyst can be further defined according to its method of acquisition. Therefore, the Ziegler-Natta catalyst is preferably obtained by a method comprising the following steps:

[0075] a)

[0076] a1) Provide a solution of at least a Group 2 metal alkoxy compound (Ax), the Group 2 metal alkoxy compound (Ax) being the product of a reaction of a Group 2 metal compound (MC) with a monohydric alcohol (A) optionally in an organic liquid reaction medium, the monohydric alcohol (A) comprising at least one ether moiety in addition to the hydroxyl moiety; or

[0077] a2) A solution of at least a Group 2 metal alkoxy compound (Ax'), wherein the Group 2 metal alkoxy compound (Ax') is optionally the product of a reaction in an organic liquid reaction medium of a mixture of a Group 2 metal compound (MC) with a monohydric alcohol (A) and a monohydric alcohol (B) having the formula ROH; or

[0078] a3) Provide a solution of a mixture of a group 2 alkoxy compound (Ax) and a group 2 metal alkoxy compound (Bx), wherein the group 2 metal alkoxy compound (Bx) is optionally the product of a reaction between a group 2 metal compound (MC) and a monohydric alcohol (B) in an organic liquid reaction medium; or

[0079] a4) The provision form is M(OR1) n (OR2) m X 2-n-m Group 2 alkoxides or Group 2 alkoxides M(OR1) n’ X 2-n’ With M(OR2) m’ X 2-m’ A solution of a mixture, wherein M is a Group 2 metal, X is a halogen, and R1 and R2 are different C2 to C3 groups. 16 An alkyl group on a carbon atom, and 0 < n<2,0 <The conditions for m < 2 and n + m + (2 - nm) = 2 are that n and m are both ≠ 0. <n’ < 2 and 0 <m’ < 2; and

[0080] b) Add the solution from step a) to a compound (TC) of at least one group 4 to 6 transition metal and

[0081] c) Obtain solid catalyst component particles

[0082] And an internal electron donor (ID) is added in any step prior to step c), preferably a non-phthalic acid internal donor (ID).

[0083] Therefore, the internal donor (ID) or its precursor is preferably added to the solution of step a) or to the transition metal compound before adding the solution of step a).

[0084] According to the above procedure, the Ziegler-Natta catalyst (ZN-C) can be obtained by precipitation or by emulsion-solidification, depending on the physical conditions, especially the temperatures used in steps b) and c). In this application, the emulsion is also referred to as a liquid / liquid two-phase system.

[0085] The catalyst chemistry is the same in both methods (precipitation and emulsion-solidification).

[0086] In the precipitation method, the solution from step a) is combined with at least one transition metal compound (TC) from step b), and the entire reaction mixture is maintained at at least 50°C, more preferably in the temperature range of 55 to 110°C, and even more preferably in the temperature range of 70 to 100°C, to ensure that the catalyst component is completely precipitated in the form of solid particles (step c).

[0087] In the emulsion-curing method, in step b), the solution from step a) is typically added to at least one transition metal compound (TC) at a relatively low temperature (e.g., below -10 to 50°C, preferably -5 to 30°C). During emulsion stirring, the temperature is typically maintained below -10 to 40°C, preferably -5 to 30°C. Droplets of the dispersed phase in the emulsion form an active catalyst composition. Curing of the droplets (step c) is suitable by heating the emulsion to a temperature of 70 to 150°C, preferably 80 to 110°C.

[0088] In this invention, a catalyst prepared by the emulsion-curing method is preferably used.

[0089] In a preferred embodiment, in step a), a solution of a2) or a3) is used, i.e., a solution of (Ax') or a mixture of (Ax) and (Bx), especially a solution of a2).

[0090] Preferably, the Group 2 metal (MC) is magnesium.

[0091] As defined above, the alkoxymagnesium compound can be prepared in situ in the first step (step a) of the catalyst preparation method by reacting a magnesium compound with one or more alcohols described above, or the alkoxymagnesium compound can be a separately prepared alkoxymagnesium compound, or it can even be commercially available as a ready-made alkoxymagnesium compound and used as is in the catalyst preparation method of the present invention.

[0092] Exemplary examples of alcohol (A) are glycol monoethers. Preferred alcohol (A) is a C2 to C4 glycol monoether, wherein the ether moiety comprises 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, with particularly preferred examples being 2-(2-ethylhexyloxy)ethanol, 1,3-propanediol-monobutyl ether, and 3-butoxy-2-propanol.

[0093] An exemplary monohydric alcohol (B) has the formula ROH, wherein R is a straight-chain or branched C2 to C3 group. 16 Alkyl residues, preferably C4 to C5 10 More preferably, C6 to C8 alkyl residues. The most preferred monohydric alcohol is 2-ethyl-1-hexanol or octanol.

[0094] It is preferred to use a mixture of Mg alkoxy compounds (Ax) and (Bx) or a mixture of alcohols (A) and (B) respectively, and to use a molar ratio of Bx:Ax or B:A of 10:1 to 1:10, more preferably 6:1 to 1:6, and most preferably 4:1 to 1:4.

[0095] The alkoxymagnesium compound can be the reaction product of one or more alcohols as defined above with a magnesium compound selected from dialkylmagnesium, alkylalkoxymagnesium, dialkoxymagnesium, alkoxymagnesium halide, and alkylhalide magnesium. Further, dialkoxymagnesium, diaryloxymagnesium, aryloxymagnesium halide, aryloxymagnesium, and alkylaryloxymagnesium can be used. The alkyl group can be similar or different C1 to C2 groups. 20 Alkyl groups, preferably C2 to C3 10 Alkyl groups. When using alkyl-alkoxy magnesium compounds, typical alkyl-alkoxy magnesium compounds 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.

[0096] Alternatively, in addition to alcohols (A) and (B), magnesium compounds can also react with the formula R''(OH). mThe alkoxymagnesium compound is obtained by reacting a polyol (C) with the polyol. If a polyol is used, the preferred polyol is one in which R'' is a straight-chain, cyclic, or branched C2 to C3 polyol. 10 An alcohol with hydrocarbon residues and m being an integer from 2 to 6.

[0097] Therefore, the alkoxymagnesium compound in step a) is selected from the group consisting of 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.

[0098] The solvent used to prepare this catalyst may be selected from aromatic hydrocarbons and straight-chain, branched, and cyclic aliphatic hydrocarbons or mixtures thereof having 5 to 20 carbon atoms, more 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.

[0099] The reaction for preparing alkoxymagnesium compounds can be carried out at temperatures ranging from 40°C to 70°C. The optimal temperature is selected based on the Mg compound and one or more alcohols used.

[0100] The transition metal compounds of groups 4 to 6 are preferably titanium compounds, and most preferably titanium halides, such as TiCl4.

[0101] In the preparation of the catalyst used in this invention, the internal donor (ID) is preferably selected from diesters of non-phthalic acid (di)carboxylic acids, 1,3-diethers, their derivatives, and mixtures thereof. Particularly preferred donors are diesters of monounsaturated dicarboxylic acids, particularly those belonging to the group comprising 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, for example, substituted maleic acid esters and citrate esters, with citrate esters being the most preferred.

[0102] In emulsion processes, a two-phase liquid-liquid system can be formed by simple stirring and optionally by adding one or more solvents and additives (such as turbulence inhibitors (also known as turbulence minimizers, TMAs) and / or emulsifiers and / or emulsion stabilizers, such as surfactants). The other one or more solvents and additives are used in a manner known in the art to promote emulsion formation and / or stabilize the emulsion. 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 inhibitor (TMA) is used, the TMA is preferably selected from α-olefin polymers of α-olefin monomers having 6 to 20 carbon atoms, such as polyoctene, polynonene, polydecene, polyundecene, or polydodecene or mixtures thereof. Polydecene is most preferred.

[0103] The solid particulate product obtained by precipitation or emulsion-solidification can be washed at least once, preferably at least twice, and most preferably at least three times with aromatic hydrocarbons and / or aliphatic hydrocarbons (preferably toluene, heptane, or pentane) and / or TiCl4. The washing solution may also contain donors and / or Group 13 compounds, such as trialkylaluminum, haloalkylaluminum compounds, or alkoxyaluminum compounds. Aluminum compounds may also be added during catalyst synthesis. The catalyst can be further dried, for example, by evaporation or nitrogen purging, or it can be slurried into an oily liquid without any drying step.

[0104] The resulting Ziegler-Natta catalyst is ideally in particulate form, typically with an average particle size of 5 to 200 μm, preferably in the range of 10 to 100 μm. These particles are dense, have low porosity, and a surface area of ​​less than 20 g / m². 2 More preferably, below 10 g / m 2 Typically, the amount of Ti is 1 to 6 by weight of the catalyst composition, the amount of Mg is 10 to 20 by weight of the catalyst composition, and the amount of the donor is 10 to 40 by weight of the catalyst composition.

[0105] Detailed descriptions of the catalyst preparation are disclosed in WO 2012 / 007430, EP2610271, EP 2610270 and EP2610272.

[0106] The Ziegler-Natta catalyst (ZN-C) is preferably used in combination with an alkylaluminum co-catalyst and optionally an external donor.

[0107] External donors (EDs) are preferably present as other components in this polymerization method. Suitable external donors (EDs) include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds, and blends thereof. Silanes are particularly preferred. Silanes having the following general formula are most preferred.

[0108] R a p R b q Si(OR c ) (4-p-q)

[0109] Where R a R b and R cThis indicates a hydrocarbon group, particularly an alkyl or cycloalkyl group, where p and q are numbers ranging from 0 to 3, and their sum p+q is equal to or less than 3. R a R b and R c These silanes can be chosen independently and can be the same or different. Specific examples of such silanes are (tert-butyl)2Si(OCH3)2 and (cyclohexyl)(methyl)Si(OCH3). 2 (phenyl)2Si(OCH3)2 and (cyclopentyl)2Si(OCH3)2, or

[0110] Silanes having the following general formula

[0111] Si(OCH2CH3)3(NR 3 R 4 )

[0112] Where R 3 and R 4 They can be the same or different, representing hydrocarbon groups with 1 to 12 carbon atoms.

[0113] R 3 and R 4 Independently selected from the group consisting of straight-chain 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 the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decyl, isopropyl, isobutyl, isopentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl, and cycloheptyl.

[0114] More preferably, R 3 and R 4 Similarly, and even more preferably, R 3 and R 4 All of them are ethyl groups.

[0115] The preferred external donors (EDs) are pentyl dimethoxysilane donors (D-donors) or cyclohexylmethyl dimethoxysilane donors (C-donors).

[0116] In addition to the Ziegler-Natta catalyst (ZN-C) and optional external donor (ED), a co-catalyst may be used. The co-catalyst is preferably a compound of Group 13 of the periodic table (IUPAC), such as an organoaluminum compound, such as an aluminum compound, like an alkylaluminum, aluminum halide, or an alkylaluminum halide. Thus, in one specific embodiment, the co-catalyst (Co) is a trialkylaluminum (such as triethylaluminum (TEAL)), a dialkylaluminum chloride, or an alkylaluminum dichloride, or a mixture thereof. In one specific embodiment, the co-catalyst (Co) is triethylaluminum (TEAL).

[0117] Advantageously, triethylaluminum (TEAL) has a hydride content (denoted as AlH3) of less than 1.0% by weight relative to triethylaluminum (TEAL). More preferably, the hydride content is less than 0.5% by weight, and most preferably, the hydride content is less than 0.1% by weight.

[0118] 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.

[0119] Therefore, the molar ratio of the co-catalyst (Co) to the external donor (ED) [Co / ED] needs to be in the range of 5 to 45, preferably in the range of 5 to 35, more preferably in the range of 5 to 25; and optionally, the molar ratio of the co-catalyst (Co) to the titanium compound (TC) [Co / TC] needs to be in the range of 80 or more to 500, preferably in the range of 100 to 350, and even more preferably in the range of 120 to 300.

[0120] As mentioned above, the Ziegler-Natta catalyst (ZN-C) is preferably modified during the prepolymerization step described above to introduce a polymer nucleating agent. Details of such modifications can be found in EP 1 183 307, EP 2 960279 and EP 3 184 587.

[0121] Such polymer nucleating agents can be vinyl polymers as described above, such as vinyl polymers derived from monomers of the following formula.

[0122] CH2=CH-CHR1R2

[0123] R1 and R2, together with the carbon atoms they are attached to, form optionally substituted saturated, unsaturated, aromatic, or fused ring systems, wherein the ring or fused ring portion contains 4 to 20 carbon atoms, preferably 5 to 12 membered saturated, unsaturated, aromatic, or fused ring systems, or R1 and R2 independently represent straight-chain or branched C4 to C30 alkanes, C4 to C20 cycloalkanes, or C4 to C20 aromatic rings. Preferably, R1 and R2, together with the C- atoms they are attached to, form five- or six-membered saturated, unsaturated, or aromatic rings, or R1 and R2 independently represent lower alkyl groups containing 1 to 4 carbon atoms. Preferred vinyl compounds, particularly vinylcycloalkanes, are used to prepare the polymer nucleating agents used according to the invention, 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.

[0124] In the modification step of the polymerization catalyst, the weight ratio of the vinyl compound to the polymerization catalyst is preferably 0.3 or more to 40, such as 0.4 to 20, or more preferably 0.5 to 15, such as 0.5 to 2.0.

[0125] The polymerization of vinyl compounds (such as VCH) can be carried out in any inert fluid that does not dissolve the resulting polymer (such as polyVCH). It is important to ensure that the final catalyst / polymerized vinyl compound / inert fluid mixture has a sufficiently high viscosity to prevent catalyst particles from settling during storage and transportation.

[0126] The viscosity of the mixture can be adjusted before or after the polymerization of vinyl compounds. For example, polymerization can be carried out in low-viscosity oils, and the viscosity can be adjusted after the polymerization of vinyl compounds by adding a high-viscosity substance. Such a high-viscosity substance can be a "wax," such as an oil or a mixture of oil and a solid or high-viscosity substance (oil-grease). The viscosity of such a viscous substance is typically 1000 to 15000 cP at room temperature. The advantage of using waxes is improved catalyst storage and feeding operations in the process. The catalyst activity is maintained because washing, drying, sieving, and transfer are eliminated.

[0127] The weight ratio of oil to solids or high-viscosity polymers is preferably less than 5:1.

[0128] In addition to viscous substances, liquid hydrocarbons, such as isobutane, propane, pentane, and hexane, can also be used as media in the modification process.

[0129] Polypropylene prepared using a catalyst modified with polymerized vinyl compounds is substantially free of free (unreacted) vinyl compounds. This means that the vinyl compounds should be completely reacted during the catalyst modification step. For this purpose, the weight ratio of the (added) vinyl compound to the catalyst should be in the range of 0.05 to 10, preferably less than 3, more preferably about 0.1 to 2.0, and particularly about 0.1 to 1.5. It should be noted that using an excess of vinyl compounds will not provide any benefit.

[0130] Furthermore, the reaction time for catalyst modification via the polymerization of vinyl compounds should be sufficient to allow the vinyl monomers to react completely, i.e., polymerization should continue until the amount of unreacted vinyl compounds in the reaction mixture (including the polymerization medium and reactants) is less than 0.5% by weight, particularly less than 2000 ppm by weight (as shown by analysis). Therefore, when the prepolymerized catalyst contains up to about 0.1% by weight of vinyl compounds, the final vinyl compound content in the polypropylene will be below the lower limit of measurement using GC-MS (<0.01 ppm by weight). Typically, when operating on an industrial scale, a polymerization time of at least 30 minutes is required, preferably at least 1 hour, particularly at least 5 hours. Polymerization times in the range of even 6 to 50 hours can be used. Modification can be carried out at temperatures from 10 to 70°C, preferably 35 to 65°C.

[0131] According to the present invention, when the catalyst is modified in the presence of an external donor with strong coordination ability, a nucleated high-rigidity propylene polymer can be obtained.

[0132] General conditions for catalyst modification are also disclosed in WO 00 / 68315, the content of which concerning the modification of polymerization catalysts is cited and incorporated herein by reference.

[0133] The preferred embodiments of vinyl compounds described above in this application also apply to the polymerization catalyst of the present invention and the preferred polypropylene compositions according to the present invention.

[0134] Besides oils, suitable media for the modification step include aliphatic inert organic solvents with low viscosity, such as pentane and heptane. Additionally, a small amount of hydrogen may be used during the modification process.

[0135] additive

[0136] As mentioned earlier, the polypropylene composition may contain additives, and the amount of additives is 0 to 5% by weight, more preferably 0 to 3% by weight, and most preferably 0 to 1.5% by weight, based on the total weight of the polypropylene composition. Such additives may be selected from the group consisting of antioxidants, acid scavengers, stabilizers, fillers, colorants, nucleating agents, slip agents, antiblocking agents, and antistatic agents. These additives are generally commercially available and described, for example, on pages 871 to 873 of, 5th edition (2001), *Plastic Additives Handbook* by Hans Zweifel.

[0137] Products

[0138] The present invention further relates to an article, preferably a film, wherein at least one layer of the article comprises the polymer composition described herein. Such films may have a thickness of 100 to 500 μm and may be oriented or non-oriented blown or cast films, preferably non-oriented cast films. More preferably, the film thickness ranges from 150 to 450 μm, such as 200 to 400 μm. The film may be a multilayer film, such as a bilayer or trilayer film, in which case the layer comprising the polymer composition described herein is the core layer. According to a preferred embodiment, the film is a single-layer film.

[0139] In a preferred embodiment, the article according to the invention is more preferably a film having a longitudinal tensile modulus of 900 to 1900 MPa, more preferably 1100 to 1800 MPa, and most preferably 1500 to 1700 MPa on a 300 μm cast film, as determined according to ISO 527-3.

[0140] It is also preferred that the article according to the invention, more preferably a film, has a haze value of 0 to 40%, more preferably 0 to 35%, and most preferably 0 to 30% on a 300 µm cast film as determined by ASTM D1003; and / or 20 to 100%, more preferably 50 to 90%, and most preferably 60 to 80% on a 300 µm cast film as determined by wide-angle X-ray scattering (WAXS). This haze value is particularly preferred because a more transparent film allows for greater visibility of the contents of the blister pack; therefore, this haze range makes the polypropylene composition according to the invention advantageous for use in blister packs. On the other hand, crystallinity is an important parameter because it is related to the final stiffness of the article made from the polypropylene composition (which is one of the main mechanical properties studied for blister packs).

[0141] Further preferably, the article according to the invention, more preferably a film, has a low water vapor transmission rate (WVTR) measured according to ISO 15106-3:2003 on a 300 µm cast film to keep the contents of the blister pack away from contaminants (in this case, water vapor), and the preferred range of the water vapor transmission rate (WVTR) is 0 to 1.0 g / m. 2 More preferably, it is 0.1 to 0.8 g / m³. 2 Even more preferably, it is 0.1 to 0.6 g / m³. 2 The optimal concentration is 0.2 to 0.5 g / m³. 2 Similarly, more preferably, the article according to the invention, more preferably a film, has a low oxygen permeability (OTR) measured according to ASTM D 3985 on a 300 µm cast film, the OTR ranging from 50 to 300 cm⁻¹. 3 / m 2 Tenba, preferably 80 to 260 cm 3 / m 2 Tenba, and the most preferred size is 100 to 200 cm. 3 / m 2 Tianba.

[0142] Further preferably, the article, more preferably a film, has good sealing performance when sealed with an aluminum-based sheet for a push-through portion of blister packaging. Therefore, it is particularly preferred that the article according to the invention, more preferably a film, has a sealing initiation temperature (SIT) of 140 to 160°C, more preferably 145 to 155°C, measured on a 300 µm cast film according to the procedure defined in this application. Further preferably, the article according to the invention, more preferably a film, has a sealing force of 4 to 15 N / cm, more preferably 4.5 to 10 N / cm, measured on a 300 µm cast film at 150°C according to the procedure defined in this application. Further preferably, the article according to the invention, more preferably a film, has a sealing force of 5 to 15 N / cm, more preferably 6 to 10 N / cm, measured on a 300 µm cast film at 180°C according to the procedure defined in this application.

[0143] use

[0144] The present invention further relates to the use of the articles described herein, more preferably films, in blister packaging (such as pharmaceutical packaging, food packaging, or non-food packaging (such as detergent or personal care product packaging)). Such blister packaging comprises a thermoformed element (which is a container for storing packaged products such as tablets or capsules) made of the film according to the invention and an aluminum-based sheet for a push-through portion. The blister packaging is sealed by sealing the flat portion of the thermoformed element made of the film according to the invention to the aluminum-based sheet.

[0145] A. Measurement Method

[0146] Unless otherwise stated, the properties of polymers prepared according to the present invention are characterized according to the methods described herein.

[0147] melt flow rate

[0148] Melt flow rate (MFR) was determined according to ISO 1133 and expressed in g / 10 min. MFR is an indicator of polymer flowability and therefore an indicator of polymer processability. A higher melt flow rate generally corresponds to a lower polymer viscosity. The MFR2 of polypropylene was determined at a temperature of 230°C and a load of 2.16 kg.

[0149] The melt flow rate MFR2 (230°C) of the polymer fraction prepared in the second polymerization reactor was calculated using the following formula:

[0150]

[0151] in

[0152] w(A) is the weight fraction of the first polymer fraction (A) obtained in the first polymerization reactor, expressed as [weight %], and MFR(A) is the melt flow rate MFR2 (230°C) of the first polymer fraction (A) obtained in the first polymerization reactor, expressed as [g / 10 min].

[0153] w(B) is the weight fraction of the second polymer fraction (B) obtained in the second polymerization reactor, expressed as [weight %], and MFR(B) is the melt flow rate MFR2 (230°C) of the second polymer fraction (B) obtained in the second polymerization reactor, expressed as [g / 10 min].

[0154] MFR(C) is the melt flow rate MFR2 (230°C) of the polymer obtained as a result of the second polymerization step (the final polymer containing fractions (A) and (B), in [g / 10 min].

[0155] Xylene cold soluble matter (XCS) content

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

[0157] Ethylene (C2) content

[0158] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantitatively analyze the comonomer content and distribution of copolymers (especially propylene-co-ethylene copolymers). Quantitative data were recorded using a Bruker Advance III 400 NMR spectrometer in solution. 13 C{ 1 HNMR spectroscopy, for 1 H and 13 C, the spectrometer operated at 400.15 MHz and 100.62 MHz, respectively. All spectra were obtained using... 13 A C-optimized 10 mm selective excitation probe was used for recording at 125 °C, with nitrogen used for all pneumatic devices. Approximately 200 mg of material was dissolved together with chromium acetylacetone-(III) (Cr(acac)3) in 1,2-tetrachloroethane-d2 (TCE-d2) to obtain a 65 mM relaxant solution in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). This setup was chosen primarily because of the high resolution and quantitative spectroscopy required for accurate determination of ethylene content. Standard single-pulse excitation was used without NOE, employing an optimized apex cone angle, a 1 s 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 (6 k) transients were obtained for each spectrum. Quantitative analysis was performed using a proprietary computer program. 13 C{ 1The ¹H NMR spectra were processed, integrated, and the relevant quantitative properties were determined from the integration. 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 allows for comparable references even if this structural unit is not present.

[0159] Characteristic signals corresponding to regio-random propylene insertion were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0160] Characteristic signals corresponding to ethylene doping were observed (Cheng, HN, Macromolecules 17, 1984, 1950). Using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157), the characteristic signals corresponding to ethylene doping were observed (Cheng, HN, Macromolecules 17, 1984, 1950). 13 Integrating multiple signals across the entire spectral region in the C-spectrum, the comonomer content is calculated as the mole fraction or percentage of incorporated ethylene relative to all monomers in the copolymer. This analytical method was chosen for its robustness and ability to account for the presence of regionally random propylene insertions when needed. Slight adjustments were made to the integration region to increase applicability across the entire range of comonomer contents encountered.

[0161] For systems where only isolated ethylene incorporation (PPEPP) is observed, the method of Wang et al. is modified to reduce the influence of non-zero integrals used to quantify higher-order comonomer sequences. In this case, the term for absolute ethylene content is determined solely based on the following equation:

[0162] E = 0.5( Sββ + Sβγ + Sβδ + 0.5( Sαβ + Sαγ)) or

[0163] E = 0.5( I H +I G + 0.5( I C + I D ))

[0164] The same notation as used in the article by Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33, 2000, 1157) is employed. The term for absolute propylene content (P) remains unchanged, and the mole fraction of ethylene is calculated as follows:

[0165] [E] = E / (E + P).

[0166] The comonomer content (in weight percentage) is calculated using conventional methods based on mole fraction, i.e.

[0167] [E weight %] = 100 * ( [E] * 28.06) / ( ([E] * 28.06) + ((1-[E]) *42.08) ).

[0168] Melting temperature Tm and crystallization temperature Tc

[0169] Melting temperature Tm and crystallization temperature Tc of 5 to 7 mg samples were measured using a TA Instrument Q2000 differential scanning calorimeter (DSC). The DSC was operated in a heating / cooling / heating cycle at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C, according to ISO 11357 / Part 3 / Method C2.

[0170] The crystallization temperature Tc is determined by the cooling step, while the melting temperature Tm is determined by the second heating step.

[0171] Molecular weight distribution

[0172] According to ISO 16014-4:2003 and ASTM D 6474-99, the molar mass average (Mw and Mn) and molecular weight distribution (MWD), i.e., Mw / Mn, are determined by gel permeation chromatography (GPC) using the following formula:

[0173]

[0174]

[0175] Where Ai and Mi represent the chromatographic peak slice area and the molecular weight (MW) of the polyolefin.

[0176] The column assembly was used at a constant flow rate of 1 ml / min using a PolymerCharGPC instrument equipped with an infrared (IR) detector, with 3 x Olexis and 1 x Olexis guard columns from Polymer Laboratories and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) as the solvent. 200 μL of sample solution was injected for each analysis. The column assembly was calibrated using universal calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards ranging from 0.5 kg / mol to 11500 kg / mol. The Mark Houwink constants for PS, PE, and PP were as described in ASTM D 6474-99. All samples were prepared by dissolving 5.0 to 9.0 mg of polymer in 8 mL (at 160 °C) of stable TCB (same as the mobile phase) for 2.5 hours at 160 °C with continuous mild shaking in the autosampler of the GPC instrument.

[0177] Tensile modulus

[0178] The longitudinal tensile modulus was determined in 300 μm cast films according to ISO 527-3.

[0179] Haze

[0180] Haze was measured on a 300 μm cast film according to ASTM D1003.

[0181] Crystallinity measured by wide-angle X-ray scattering (WAXS)

[0182] Wide-angle X-ray scattering (WAXS) measurements of the samples were performed using a Bruker D8 Discover instrument. The diffractometer was equipped with an X-ray tube with a copper target operating at 30 kV and 20 mA, and a GADDS 2-D detector. The beam was guided onto the surface using point collimation (0.5 mm). Measurements were performed in reflection geometry, measuring 28 angles ranging from 10° to 32.5°. Data collection time was 300 s. Intensity versus 2-θ curves were obtained for amorphous polypropylene samples prepared by solvent extraction using the same measurement parameters. Amorphous halo was obtained by curve smoothing. The amorphous halo was subtracted from the measured intensity versus 2-θ curves to obtain the crystalline curve.

[0183] The crystallinity index Xc can be defined by the area under the crystallization curve and the area under the original spectrum using the method of Challa, Hermans, and Weidinger [Challa F, Hermans PH, Weidinger A, Makromol. Chem. 56, 169 (1962)].

[0184]

[0185] Water vapor transmission rate (WVTR)

[0186] Water vapor transmission rate (WVTR) was measured on a 300 μm cast film according to ISO 15106-3:2003.

[0187] Equipment: Mocon Aquatran

[0188] Temperature: 38℃±0.3℃.

[0189] Relative humidity: 0 / 90% Sample area: 5 cm² 2

[0190] Oxygen permeability (OTR)

[0191] Oxygen permeability (OTR) was measured on a 300 μm cast film. The sample was installed as a sealed semi-barrier layer between two chambers at ambient atmospheric pressure. One chamber was slowly purged with a flow of a nitrogen and hydrogen gas mixture (N2 containing 2% H2) at a given temperature and relative humidity, and the other chamber was purged with an oxygen flow at the same temperature and relative humidity as the N2 flow. As oxygen permeated through the film into the nitrogen carrier gas, it was delivered to a coulometric detector, where it generated an electric current proportional to the amount of oxygen flowing into the detector per unit time. According to ASTM D 3985, at 23°C and 50% relative humidity, and at 5°C and 0% relative humidity, a gas flow of 10 sccm for N2 / H2 and O2 (99.999%) and a 1 cm⁻¹ flow rate were used. 2 The oxygen permeability of the sheet surface area was tested.

[0192] Sealing performance

[0193] Heat-sealing experiments were performed on at least three film samples (cut longitudinally, 85 mm wide, 200 mm long, and 300 μm thick). A 5 mm × 150 mm PTFE-coated heating rod was set to different sealing temperatures. Two films were positioned by placing one film on top of the other and sealed using a sealing time of 0.5 s and a pressure of 0.67 MPa. The resulting sealed area was 85 mm × 5 mm. The samples were then conditioned for 7 days (±24 hours) at 23°C (±2°C) / 50% RH (±10%). Ten 15 mm wide samples were cut and tested in tensile mode at 23°C (±2°C) / 50% RH (±10%) on a universal testing machine (Zwick Z005) at a test speed of 200 mm / min.

[0194] Basic seal:

[0195] • Film width: 85 mm

[0196] • Film length: >200 mm

[0197] • Sealing joint width: 5 mm

[0198] • Sealing temperature: 140℃ to 180℃

[0199] • Sealing pressure: 0.67 N / mm 2

[0200] • Sealing time: 0.5 s

[0201] • Sealing jaws: coated with polytetrafluoroethylene

[0202] adjust:

[0203] • Conditioning time: 7 days (±24 hours) at 23℃ (±2℃) / 50% RH (±10%)

[0204] Heat seal strength:

[0205] • Test temperature: 23℃ (±2℃) / 50% RH (±10%)

[0206] • Sample width: 15 mm

[0207] Clamping distance: 100 mm

[0208] • Test rate: 200 mm / min

[0209] • Testing equipment: Universal testing machine

[0210] B. Example

[0211] The base polymers used for IE1 and CE1 were prepared using the same catalyst (described below), and the polymerization conditions are shown in Table 1. Both polymers were prepared in a Borstar pilot plant equipped with a prepolymerization reactor, a slurry loop reactor, and a gas-phase reactor. The solid catalyst was used in conjunction with triethylaluminum (TEAL) as a cocatalyst and dicyclopentyldimethoxysilane (D-donor) as a donor.

[0212] 1a) Catalyst preparation

[0213] 3.4 L of 2-ethylhexanol and 810 mL of propylene glycol monobutyl ether (molar ratio 4 / 1) were added to a 20 L reactor. Then, 7.8 L of a 20% BEM (butylethyl magnesium) toluene solution (supplied by Crompton GmbH) was slowly added to the well-stirred alcohol mixture. The temperature was maintained at 10 °C during the addition. After the addition, the temperature of the reaction mixture was raised to 60 °C and mixing continued at this temperature for 30 minutes. Finally, after cooling to room temperature, the resulting alkoxymagnesium was transferred to a storage container.

[0214] 21.2 g of the alkoxymagnesium prepared above was mixed with 4.0 ml of bis(2-ethylhexyl) citrate for 5 minutes. The resulting magnesium complex was immediately used in the preparation of the catalyst component.

[0215] 19.5 ml of titanium tetrachloride was added to a 300 ml reactor equipped with a mechanical stirrer at 25°C. The mixing speed was adjusted to 170 rpm. Maintaining the temperature at 25°C, 26.0 g of the magnesium-complex prepared above was added over 30 minutes. 3.0 ml of Viscoplex 1-254 and 24.0 ml of heptane were added to form an emulsion. Mixing was continued at 25°C for 30 minutes. Subsequently, the reactor temperature was increased to 90°C over 30 minutes. The reaction mixture was further stirred at 90°C for 30 minutes. Stirring was then stopped, and the reaction mixture was allowed to stand at 90°C for 15 minutes.

[0216] The solid material was washed with 100 ml toluene, 30 ml TiCl4, 100 ml toluene, and twice with 60 ml heptane. 1 ml of the donor was added during the first two washes. The washing was performed by stirring at 170 rpm for 30 min at 80 °C. After stirring was stopped, the reaction mixture was allowed to stand for 20 to 30 minutes, followed by siphoning.

[0217] The solid material was washed five times: at 80°C and 170 rpm for 30 minutes. After stirring was stopped, the reaction mixture was allowed to stand for 20 to 30 minutes, followed by siphoning.

[0218] Wash 1: Wash with a mixture of 100 ml toluene and 1 ml of the donor.

[0219] Washing 2: Wash with a mixture of 30 ml TiCl4 and 1 ml of the donor.

[0220] Washing 3: Wash with 100 ml of toluene.

[0221] Washing 4: Wash with 60 ml of heptane.

[0222] Washing 5. Wash with 60 ml of heptane and stir for 10 minutes.

[0223] Then stop stirring and let the reaction mixture stand for 10 minutes, lower the temperature to 70°C, then siphon, followed by 20 minutes of nitrogen bubbling to produce an air-sensitive powder.

[0224] 1b) VCH modification of catalysts

[0225] At room temperature and under inert conditions, 35 ml of mineral oil (liquid paraffin PL68) was added to a 125 ml stainless steel reactor, followed by 0.82 g of triethylaluminum (TEAL) and 0.33 g of dicyclopentyldimethoxysilane (donor D). After 10 minutes, 5.0 g of the catalyst prepared in step 1a (1.4 wt% titanium content) was added, followed by 5.0 g of vinylcyclohexane (VCH) after another 20 minutes. The temperature was raised to 60 °C over 30 minutes and maintained at this temperature for 20 hours. Finally, the temperature was lowered to 20 °C, and the concentration of unreacted VCH in the oil / catalyst mixture was analyzed, yielding a result of 120 ppm by weight.

[0226] Table 1. Aggregation conditions for IE1 and CE1

[0227]

[0228] *Calculated,** measured

[0229] The base polymers prepared according to Table 1 were then mixed with different additives in a high-intensity mixer, and IE1 and CE1 were prepared in a co-rotating twin-screw extruder at a temperature of 200 to 220°C, followed by granulation. In the mixing method, CE1 was viscous-reduced and cracked using a suitable amount of masterbatch (5% by weight of 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane with polypropylene). The formulations and some properties measured on the granules are shown in Table 2, where AO1 is Irganox 1010 (supplied by BASF AG, Germany), AO2 is Irgafos 168 (supplied by BASF AG, Germany), and AS is synthetic hydrotalcite (DHT-4A, supplied by Kisuma Chemicals, Netherlands).

[0230] Table 2. Formulations of compounds prepared from IE1 and CE1

[0231]

[0232] Comparative Example CE2 contains DM55pharm as the base polymer, DM55pharm has a melt flow rate (MFR2) of 2.8 g / 10 min and a density of 905 kg / m³. 3 A commercially available polypropylene homopolymer (sold by Borealis AG) with a melting temperature Tm of 163°C, a crystallization temperature Tc of 116°C, and a xylene cold soluble (XCS) content (as determined according to ISO 16152) of 3.0% by weight.

[0233] Cast films were prepared using IE1, CE1, and CE2 on a Collin laboratory-scale casting film production line with a melt temperature of 220°C, a cooling roll temperature of 60°C, and a production rate of 8 kg / h. To obtain films with sufficient transparency, CE2 was also processed at the same melt temperature with a cooling roll temperature of 20°C and a production rate of 8 kg / h (CE3 in Table 3 below). The resulting film thickness was 300 µm. The films were subsequently characterized, and the results are reported in Table 3 below.

[0234] Table 3. Thin Film Properties

[0235]

[0236] As can be clearly seen from Table 3, compared with CE1, CE2 and CE3, the film made of IE1 exhibits improved stiffness and lower haze, water vapor transmission rate and oxygen transmission rate.

[0237] The films IE1, CE1, and CE3 were then heat-sealed with a standard aluminum film (ALU 20MY HMFBL / GL.HS, supplied by Constantia) with a 20 μm thickness and a styrene elastomer coating as a sealing layer, as this is commonly used in push-through tablet blister packs in the industry. This sealing method for the multilayer film structure was performed over a length of 85 mm, with a sealing head width of 5 mm, a sealing time of 0.5 s, and a pressure of 0.67 MPa. Sealing strength was tested as is typically done for polymer / polymer seals, revealing differences in strength at both seal initiation and low sealing temperatures. Sealing performance is reported in Table 4 below, where SIT is the seal initiation temperature, defined as the temperature at which the sealing force (SF) exceeds 5 N / cm.

[0238] Table 4. Sealing performance of multilayer films

[0239]

[0240] Compared to CE1, the sealing performance of embodiment IE1 is significantly improved in terms of sealing force at SIT and 150°C, while also having better crystallinity, stiffness and barrier properties.

Claims

1. A polypropylene composition comprising: a) a homopolymer of propylene in an amount of 95 to 100 wt%, based on the total weight of the polypropylene composition, and b) optionally, additives in an amount of 0 to 5 wt%, based on the total weight of the polypropylene composition; wherein the polypropylene composition has: - a melt flow rate MFR2, determined according to ISO 1133 at 230 °C under a load of 2.16 kg, of 2.5 to 12.0 g / 10 min; - a xylene cold soluble (XCS) content, determined according to ISO 16152, of 0.1 to 1.8 wt%; - 0 to 0.5 wt% of a compound of formula (I) 13 Ethylene content determined by C-NMR spectroscopy; - a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), Mw / Mn, determined according to the GPC method described herein, of 4.5 to 9.0, preferably 5.0 to 8.0; - a melting temperature Tm, determined according to ISO 11357 / Part 3 / Method C2, of 160 to 175 °C; and - a crystallization temperature Tc, determined according to ISO 11357 / Part 3 / Method C2, of 122 to 135 °C.

2. The polypropylene composition according to claim 1 having: a) a melt flow rate MFR2, determined according to ISO 1133 at 230 °C under a load of 2.16 kg, of 3.0 to 8.0 g / 10 min, more preferably 4.0 to 7.0 g / 10 min; and / or b) a xylene cold soluble (XCS) content, determined according to ISO 16152, of 0.2 to 1.5 wt%, more preferably 0.5 to 1.0 wt%.

3. The polypropylene composition according to any of the preceding claims having an ethylene content of 0 to 0.3 wt.%, more preferably 0 to 0.2 wt.%. 13 Ethylene content determined by C-NMR spectroscopy.

4. The polypropylene composition according to any one of the preceding claims having a tensile modulus in machine direction, determined according to ISO 527-3 on a 300 pm cast film, of 900 to 1900 MPa, more preferably 1100 to 1800 MPa, and most preferably 1500 to 1700 MPa.

5. The polypropylene composition according to any one of the preceding claims having: a) a haze value, determined according to ASTM D1003 on a 300 pm cast film, of 0 to 40%, more preferably 0 to 35%, and most preferably 0 to 30%; and / or b) a crystallinity value, determined by wide angle X-ray scattering (WAXS) on a 300 pm cast film, of 20 to 100%, more preferably 50 to 90%, and most preferably 60 to 80%.

6. The polypropylene composition according to any of the preceding claims having a water vapor transmission rate (WVTR) determined on a 300 pm cast film according to ISO 15106-3:2003 of 0 to 1.0 g / m 2 day, more preferably 0.1 to 0.8 g / m 2 day, even more preferably 0.1 to 0.6 g / m 2 day and most preferably 0.2 to 0.5 g / m 2 day.

7. The polypropylene composition according to any of the preceding claims having an oxygen transmission rate (OTR) determined according to ASTM D3985 on a 300 pm cast film of 50 to 300 cm 3 / m 2 daybar, more preferably 80 to 260 cm 3 / m 2 daybar, and most preferably 100 to 200 cm 3 / m 2 daybar.

8. The polypropylene composition according to any one of the preceding claims having a seal initiation temperature (SIT), determined according to the procedure defined in this application on a 300 pm cast film, of 140 to 160 °C, more preferably 145 to 155 °C.

9. A process for obtaining the polypropylene composition according to claims 1 to 9, in a multi-stage polymerization process, comprising the steps of: a) polymerizing propylene in the presence of a Ziegler-Natta catalyst in a first polymerization reactor (R1) and obtaining a first polymerization product; b) transferring the first polymerization product to a second polymerization reactor (R2) and obtaining a final polymerization product; and c) optionally, adding additives to the final polymerization product. c) Optionally, compounding the final polymeric product obtained in step b) with additives.

10. The process according to claim 9, wherein the following step is performed prior to step a): a0) modifying a Ziegler-Natta catalyst, preferably with a polymeric nucleating agent, more preferably with an ethylene-based polymer, in a prepolymerization reactor and prepolymehzing propylene.

11. The process according to any one of claims 9 to 10, wherein the Ziegler-Natta catalyst comprises: a) a compound of a transition metal of IUPAC Groups 4 to 6; b) a compound of a metal of IUPAC Group 2; c) an internal donor, i.e. a non-phthalic compound, preferably a non-phthalate ester; d) a cocatalyst; and e) optionally, an external donor.

12. An article, preferably a film, comprising the polypropylene composition according to claims 1 to 8.

13. The article according to claim 12, wherein the article is a blown film or a cast film having a thickness of 100 to 500 pm.

14. Use of the article according to claims 12 to 13 in medical packaging.

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