Recyclable multilayer film with a sealing layer formed of polypropylene blend

Abstract

A multilayer film (F) comprising, in a given order, layers: (A) a surface layer; (B) a core layer; and (C) a sealing layer, the sealing layer comprising at least 90 wt% of a polypropylene composition (PC) comprising: i) 20 to 70 wt% of RAHECO having an MFR2 of 0.1 to 10.0 g / 10 min; ii) 10 to 50 wt% of a first propylene-ethylene random copolymer (R-PP1) having an MFR2 of 1.0 to 6.0 g / 10 min; and iii) 10 to 50 wt% of a second propylene-ethylene random copolymer (R-PP2) having an MFR2 of 7.0 to 20 g / 10 min.

Description

Technical Field

[0001] The present invention relates to a multilayer film (F) comprising a surface layer, a core layer and a sealing layer, wherein the sealing layer comprises a polypropylene composition comprising RAHECO and two propylene-ethylene random copolymers. Background Technology

[0002] Plastic packaging is widely used in daily life due to its good cost performance. Polyolefins are simple and economical to produce, have good performance, and are widely used in plastic packaging.

[0003] The packaging industry often demands conflicting properties. For example, plastic films may require both high stiffness and toughness, as well as excellent sealing performance and good optical properties. Different types of polyolefins (such as polypropylene and polyethylene) are often combined in blends and / or used in different layers of multilayer films to achieve the desired properties. However, using more than one polymer type complicates the task of packaging recycled plastics.

[0004] One approach to achieving recycling is the "single-material solution," where only one type of polymer material is used. This simplifies the recycling of post-consumer and production waste but limits the range of achievable performance. Therefore, there remains a need for plastic packaging formed from a single polymer type (although it may contain various grades of different polymer types) that optimizes the mechanical, optical, and sealing properties required for the packaging material while also being easily recyclable. Summary of the Invention

[0005] Therefore, the present invention relates to a multilayer film (F) comprising, in a given order, the following layers:

[0006] (A) Surface layer, which, based on the total weight of the surface layer, comprises at least 90 wt% polypropylene or a mixture of polypropylene;

[0007] (B) Core layer, which, based on the total weight of the core layer, contains at least 90 wt% polypropylene or a mixture of polypropylene;

[0008] (C) A sealing layer, based on the total weight of the sealing layer, comprising at least 90 wt% of a polypropylene composition (PC), the polypropylene composition (PC) comprising the following components:

[0009] i) Based on the total weight of the polypropylene composition (PC), 20 to 70 wt% of a random multiphase propylene-ethylene copolymer (RAHECO), said random multiphase propylene-ethylene copolymer (RAHECO) having a melt flow rate (MFR2) of 0.1 to 10.0 g / 10 min as measured according to ISO 1133 at 230 °C and 2.16 kg and comprising:

[0010] a) A crystalline matrix (M), wherein the crystalline matrix (M) is a random copolymer of propylene and ethylene; and

[0011] b) Amorphous propylene-ethylene elastomer (E);

[0012] ii) 10 to 50 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC), wherein the first propylene-ethylene random copolymer (R-PP1) has a melt flow rate (MFR2) of 1.0 to 6.0 g / 10 min as measured according to ISO 1133 at 230 °C and 2.16 kg; and

[0013] iii) 10 to 50 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC), wherein the melt flow rate (MFR2) of the second propylene-ethylene random copolymer (R-PP2) is 7.0 to 20 g / 10 min as measured according to ISO 1133 at 230 °C and 2.16 kg.

[0014] Wherein, relative to the total weight of the polypropylene composition (PC), the aggregate of the random multiphase propylene-ethylene copolymer (RAHECO), the first propylene-ethylene random copolymer (R-PP1), and the second propylene-ethylene random copolymer (R-PP2) is at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt%. Detailed Implementation

[0015] definition

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While any methods and materials similar to or equivalent to those described herein may be used in practice to test the invention, preferred materials and methods are described herein. In describing and claiming protection for this invention, the following terms will be used in accordance with the definitions listed below.

[0017] Unless otherwise expressly stated, the use of terms such as “a” or “an” refers to more than one.

[0018] In the following text, unless otherwise stated, quantities are given as a weight percentage (wt%).

[0019] Propylene homopolymer is a polymer that is essentially composed of propylene monomer units. Due to impurities, particularly during commercial polymerization processes, propylene homopolymer may contain up to 0.1 mol%, preferably up to 0.05 mol%, and most preferably up to 0.01 mol% of comonomer units.

[0020] Propylene copolymers are copolymers of propylene monomer units and comonomer units (preferably selected from ethylene and C4-C8 α-olefins). Propylene random copolymers are propylene copolymers in which the comonomer units are randomly distributed along the polymer chain, while propylene block copolymers comprise propylene monomer unit blocks and comonomer unit blocks. Propylene random copolymers may contain comonomer units derived from more than one comonomer with different carbon atomic weights.

[0021] Multiphase propylene copolymers typically contain:

[0022] a) A crystalline propylene homopolymer or copolymer matrix (M); and

[0023] b) Elastomer rubber, preferably propylene-ethylene elastomer (E);

[0024] In the case of a random multiphase propylene copolymer, the crystalline matrix phase is a random copolymer of propylene and at least one α-olefin comonomer.

[0025] The elastomeric phase can be a propylene copolymer with a large number of comonomers, which are not randomly distributed in the polymer chain, but rather distributed in comonomer-rich block structures and propylene-rich block structures. Multiphase polypropylene generally differs from single-phase propylene copolymers because it exhibits two distinct glass transition temperatures Ti attributable to the matrix phase and the elastomeric phase. g .

[0026] The invention will now be described in more detail.

[0027] Detailed description

[0028] Therefore, the present invention relates to a multilayer film (F) comprising, in a given order, the following layers:

[0029] (A) Surface layer;

[0030] (B) Core layer; and

[0031] (C) Sealing layer.

[0032] sealing layer

[0033] The sealing layer of the present invention comprises at least 90 wt% of a polypropylene composition (PC), more preferably at least 95 wt% of a polypropylene composition (PC), even more preferably at least 97 wt% of a polypropylene composition (PC), and most preferably, the sealing layer is composed of a polypropylene composition (PC).

[0034] The polypropylene composition (PC) comprises the following components:

[0035] i) 20 to 70 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0036] ii) 10 to 50 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0037] iii) 10 to 50 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0038] The total amount of the random multiphase propylene-ethylene copolymer (RAHECO), the first propylene-ethylene random copolymer (R-PP1), and the second propylene-ethylene random copolymer (R-PP2) relative to the total weight of the polypropylene composition (PC) is at least 90 wt%, more preferably at least 95 wt%, and even more preferably at least 97 wt%.

[0039] More preferably, the polypropylene composition (PC) comprises the following components:

[0040] i) 25 to 60 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0041] ii) 12 to 48 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0042] iii) 12 to 48 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0043] Most preferably, the polypropylene composition (PC) comprises the following components:

[0044] i) 30 to 50 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0045] ii) 15 to 45 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0046] iii) 15 to 45 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0047] In a particularly preferred embodiment, the polypropylene composition (PC) comprises the following components:

[0048] i) 30 to 50 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0049] ii) 10 to 20 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0050] iii) 40 to 50 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0051] In an alternative embodiment, the polypropylene composition (PC) comprises the following components:

[0052] i) 30 to 50 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0053] ii) 25 to 35 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0054] iii) 25 to 35 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0055] In another alternative embodiment, the polypropylene composition (PC) comprises the following components:

[0056] i) 30 to 50 wt% random multiphase propylene-ethylene copolymer (RAHECO) based on the total weight of the polypropylene composition (PC);

[0057] ii) 40 to 50 wt% of a first propylene-ethylene random copolymer (R-PP1) based on the total weight of the polypropylene composition (PC); and

[0058] iii) 10 to 20 wt% of a second propylene-ethylene random copolymer (R-PP2) based on the total weight of the polypropylene composition (PC).

[0059] If there are components other than random multiphase propylene-ethylene copolymer (RAHECO), first propylene-ethylene random copolymer (R-PP1), and second propylene-ethylene random copolymer (R-PP2), these components are preferably additives.

[0060] Those skilled in the art will be able to select appropriate additives known in the art.

[0061] Preferably, the additives are selected from pigments, antioxidants, UV stabilizers, scratch inhibitors, release agents, acid removers, lubricants, antistatic agents, and mixtures thereof.

[0062] It should be understood that the amount of additives includes any carrier polymer used to introduce the additives into the polypropylene composition (PC), i.e., the masterbatch carrier polymer. An example of such a carrier polymer is a polypropylene homopolymer in powder form.

[0063] The components will now be described in more detail.

[0064] Random multiphase propylene-ethylene copolymer (RAHECO)

[0065] The content of random multiphase propylene-ethylene copolymer (RAHECO) relative to the total weight of the polypropylene composition (PC) is 20.0 to 70.0 wt%, more preferably 25.0 to 60.0 wt%, and most preferably 30.0 to 50.0 wt%.

[0066] Random multiphase propylene-ethylene copolymer (RAHECO) comprises:

[0067] a) A crystalline matrix (M), wherein the crystalline matrix (M) is a random copolymer of propylene and ethylene; and

[0068] b) Amorphous propylene-ethylene elastomer (E).

[0069] The random multiphase propylene-ethylene copolymer (RAHECO) has a melt flow rate (MFR2) of 0.1 to 10.0 g / 10 min, more preferably 0.3 to 5.0 g / 10 min, and most preferably 0.5 to 2.0 g / 10 min, as measured according to ISO 1133 at 230 °C and 2.16 kg.

[0070] The melting temperature (T) of random multiphase propylene-ethylene copolymer (RAHECO) determined by differential scanning calorimetry (DSC) m The temperature is preferably 130 to 155°C, more preferably 134 to 150°C, and most preferably 138 to 145°C.

[0071] If passed 13 C-NMR spectroscopy analysis showed that the crystalline matrix (M) of the random multiphase propylene-ethylene copolymer (RAHECO) preferably does not contain 2,1-region defects.

[0072] The absence of 2,1-region defects indicates that the random multiphase propylene-ethylene copolymer (RAHECO) was polymerized in the presence of a Ziegler-Natta catalyst.

[0073] Therefore, more preferably, the random multiphase propylene-ethylene copolymer (RAHECO) is polymerized in the presence of a Ziegler-Natta catalyst.

[0074] The polymer fraction of the random multiphase propylene-ethylene copolymer (RAHECO) can be characterized using trichlorobenzene (TCB) as a solvent according to the CRYSTEX QC method. This method is described in the determination method section below. The crystalline fraction (CF) mainly contains the matrix phase and only a small portion of the elastomer phase, while the soluble fraction (SF) mainly contains the elastomer phase and only a small portion of the matrix phase. In some cases, this method yields more useful data because the crystalline fraction (CF) and soluble fraction (SF) correspond more accurately to the matrix and elastomer phases, respectively. Due to the differences in separation methods between xylene extraction and the CRYSTEX QC method, the properties of the XCS / XCI fractions are not entirely the same, and the properties of the crystalline / soluble (CF / SF) fractions are also not entirely the same. This means that the amounts and properties of the matrix and elastomer phases may differ.

[0075] The ethylene content (C2 (total)) of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 3.0 to 15.0 wt%, more preferably 5.0 to 13.0 wt%, and most preferably 7.0 to 11.0 wt%.

[0076] The soluble fraction (SF) content of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 10 to 45 wt%, more preferably 13 to 35 wt%, and most preferably 16 to 25 wt%.

[0077] The ethylene content (C2(SF)) of the soluble fraction of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 17.0 to 60.0 wt%, more preferably 20.0 to 50.0 wt%, and most preferably 25.0 to 40.0 wt%.

[0078] The intrinsic viscosity (iV(SF)) of the soluble fraction of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 1.20 to 4.50 dL / g, more preferably 2.00 to 4.00 dL / g, and most preferably 2.40 to 3.40 dL / g.

[0079] The random multiphase propylene-ethylene copolymer (RAHECO) has a crystalline fraction (CF) content of 55 to 90 wt%, more preferably 65 to 87 wt%, and most preferably 75 to 84 wt%, as determined by CRYSTEX QC analysis.

[0080] The ethylene content (C2(CF)) of the crystalline fraction of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 1.0 to 8.0 wt%, more preferably 2.0 to 7.0 wt%, and most preferably 3.0 to 6.0 wt%.

[0081] The intrinsic viscosity (iV(CF)) of the crystalline fraction of the random multiphase propylene-ethylene copolymer (RAHECO), as determined by CRYSTEX QC analysis, is preferably 1.20 to 4.50 dL / g, more preferably 2.00 to 4.00 dL / g, and most preferably 2.60 to 3.60 dL / g.

[0082] Furthermore, preferably, the intrinsic viscosity ratio (iV(SF) / iV(CF)) of the soluble fraction and the crystalline fraction, as measured by CRYSTEX QC analysis, is 0.50 to 2.00, more preferably 0.75 to 1.50.

[0083] First propylene-ethylene random copolymer (R-PP1)

[0084] The amount of the first propylene-ethylene random copolymer (R-PP1) present in the polypropylene composition (PC) relative to the total weight of the polypropylene composition (PC) is 10.0 to 50.0 wt%, more preferably 12.0 to 48.0 wt%, and most preferably 15.0 to 45.0 wt%.

[0085] Those skilled in the art will understand that the first propylene-ethylene random copolymer (R-PP1) is a single phase compared to the random multiphase propylene-ethylene copolymer (RAHECO).

[0086] The first propylene-ethylene random copolymer (R-PP1) is a random copolymer having propylene monomer units and ethylene comonomer units.

[0087] The first propylene-ethylene random copolymer (R-PP1) has a melt flow rate (MFR2) of 1.0 to 6.0 g / 10 min, more preferably 1.2 to 4.5 g / 10 min, and most preferably 1.6 to 3.0 g / 10 min, as measured according to ISO 1133 at 230 °C and 2.16 kg.

[0088] The first propylene-ethylene random copolymer (R-PP1) was quantitatively analyzed. 13 The ethylene content (C2) measured by C-NMR spectroscopy is preferably 1.0 to 5.5 wt%, more preferably 1.0 to 3.5 wt%, and most preferably 1.0 to 2.0 wt%.

[0089] The xylene cold solubles (XCS) content of the first propylene-ethylene random copolymer (R-PP1), as determined by analysis according to ISO 16152, is preferably 0.2 to 5.0 wt%, more preferably 0.3 to 3.0 wt%, and most preferably 0.4 to 1.0 wt%.

[0090] The melting temperature (T1) of the first propylene-ethylene random copolymer (R-PP1) was determined by differential scanning calorimetry (DSC). m The temperature is preferably 130 to 155°C, more preferably 136 to 151°C, and most preferably 142 to 148°C.

[0091] The crystallization temperature (Tc) of the first propylene-ethylene random copolymer (R-PP1) was determined by differential scanning calorimetry (DSC). c The temperature is preferably 110 to 125°C, more preferably 112 to 122°C, and most preferably 114 to 119°C.

[0092] The first propylene-ethylene random copolymer (R-PP1) was obtained through 13 The content of 2,1-region defects as measured by C-NMR spectroscopy is preferably 0.05 to 1.40 mol%, more preferably 0.10 to 1.10 mol%, and most preferably 0.20 to 0.90 mol%.

[0093] The presence of 2,1-region defects indicates that the first propylene-ethylene random copolymer (R-PP1) was polymerized in the presence of a single-site catalyst (SSC).

[0094] Therefore, more preferably, the first propylene-ethylene random copolymer (R-PP1) is polymerized in the presence of a single-site catalyst (SSC).

[0095] Second propylene-ethylene random copolymer (R-PP2)

[0096] The amount of the second propylene-ethylene random copolymer (R-PP2) present in the polypropylene composition (PC) relative to the total weight of the polypropylene composition (PC) is 10.0 to 50.0 wt%, more preferably 12.0 to 48.0 wt%, and most preferably 15.0 to 45.0 wt%.

[0097] Those skilled in the art will understand that the second propylene-ethylene random copolymer (R-PP2) is a single phase compared to the random multiphase propylene-ethylene copolymer (RAHECO).

[0098] The second propylene-ethylene random copolymer (R-PP2) is a random copolymer containing propylene monomer units and ethylene comonomer units.

[0099] The melt flow rate (MFR2) of the second propylene-ethylene random copolymer (R-PP2), measured according to ISO 1133 at 230°C and 2.16 kg, is 7.0 to 20.0 g / 10 min, more preferably 8.0 to 17.0 g / 10 min, and most preferably 9.0 to 14.0 g / 10 min.

[0100] The second propylene-ethylene random copolymer (R-PP2) was quantitatively analyzed. 13 The ethylene content (C2) measured by C-NMR spectroscopy is preferably 1.0 to 5.5 wt%, more preferably 1.5 to 4.0 wt%, and most preferably 2.0 to 3.0 wt%.

[0101] The xylene cold solubles (XCS) content of the second propylene-ethylene random copolymer (R-PP2), as determined by analysis according to ISO 16152, is preferably 0.2 to 5.0 wt%, more preferably 0.3 to 3.0 wt%, and most preferably 0.4 to 1.0 wt%.

[0102] The melting temperature (T2) of the second propylene-ethylene random copolymer (R-PP2) was determined by differential scanning calorimetry (DSC). m The temperature is preferably 125 to 145°C, more preferably 126 to 135°C, and most preferably 127 to 130°C.

[0103] The crystallization temperature (Tc) of the second propylene-ethylene random copolymer (R-PP2) was determined by differential scanning calorimetry (DSC). c The temperature is preferably 100 to 120°C, more preferably 103 to 115°C, and most preferably 106 to 110°C.

[0104] The second propylene-ethylene random copolymer (R-PP2) was obtained through 13 The content of 2,1-region defects as measured by C-NMR spectroscopy is preferably 0.05 to 1.40 mol%, more preferably 0.10 to 1.10 mol%, and most preferably 0.20 to 0.90 mol%.

[0105] The presence of 2,1-region defects indicates that the second propylene-ethylene random copolymer (R-PP2) has been polymerized in the presence of a single-site catalyst (SSC).

[0106] Therefore, more preferably, the second propylene-ethylene random copolymer (R-PP2) is polymerized in the presence of a single-site catalyst (SSC).

[0107] Surface and core layers

[0108] The outer layer (A) and the core layer (B) each contain at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt% of polypropylene or a mixture of polypropylene.

[0109] The composition of the surface layer (A) and the core layer (B) may be the same or different. Preferably, the composition of the surface layer (A) is the same as that of the core layer (B).

[0110] In the broadest sense, any polypropylene can be used for both the top layer (A) and the core layer (B).

[0111] However, the surface layer (A) contains preferably at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt% of a multiphase propylene-ethylene copolymer or a mixture of multiphase propylene-ethylene copolymers.

[0112] Similarly, the core layer (B) comprises preferably at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt% of a multiphase propylene-ethylene copolymer or a mixture thereof.

[0113] Particularly preferably, the surface layer (A) comprises at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt% of a polypropylene composition (PC'), said polypropylene composition (PC') comprising:

[0114] i) 15 to 45 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'),

[0115] The random multiphase propylene-ethylene copolymer (RAHECO') comprises:

[0116] a1) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene-ethylene random copolymer; and

[0117] b1) Amorphous propylene-ethylene elastomer (E); and

[0118] ii) 55 to 85 wt% of a multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0119] The multiphase propylene-ethylene copolymer (HECO) comprises:

[0120] a2) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene homopolymer; and

[0121] b2) Amorphous propylene-ethylene elastomer (E).

[0122] The total amount of random multiphase propylene-ethylene copolymer (RAHECO') and multiphase propylene-ethylene copolymer (HECO) relative to the total weight of the polypropylene composition (PC') is at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt%.

[0123] More preferably, the polypropylene composition (PC') comprises:

[0124] i) 20 to 40 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'); and

[0125] ii) 60 to 80 wt% of multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0126] More preferably, the polypropylene composition (PC') comprises:

[0127] i) 25 to 35 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'); and

[0128] ii) 65 to 75 wt% of multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0129] Also particularly preferably, the core layer (B) comprises at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt% of a polypropylene composition (PC'), said polypropylene composition (PC') comprising:

[0130] i) 15 to 45 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'),

[0131] The random multiphase propylene-ethylene copolymer (RAHECO') comprises:

[0132] a1) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene-ethylene random copolymer; and

[0133] b1) Amorphous propylene-ethylene elastomer (E); and

[0134] ii) 55 to 85 wt% of a multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0135] The multiphase propylene-ethylene copolymer (HECO) comprises:

[0136] a2) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene homopolymer; and

[0137] b2) Amorphous propylene-ethylene elastomer (E).

[0138] The total amount of random multiphase propylene-ethylene copolymer (RAHECO') and multiphase propylene-ethylene copolymer (HECO) relative to the total weight of the polypropylene composition (PC') is at least 90 wt%, more preferably at least 95 wt%, and most preferably at least 97 wt%.

[0139] More preferably, the polypropylene composition (PC') of the core layer (B) comprises:

[0140] i) 20 to 40 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'); and

[0141] ii) 60 to 80 wt% of multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0142] More preferably, the polypropylene composition (PC') of the core layer (B) comprises:

[0143] i) 25 to 35 wt% of random multiphase propylene-ethylene copolymer (RAHECO') based on the total weight of the polypropylene composition (PC'); and

[0144] ii) 65 to 75 wt% of multiphase propylene-ethylene copolymer (HECO) based on the total weight of the polypropylene composition (PC').

[0145] If components other than random multiphase propylene-ethylene copolymer (RAHECO') and multiphase propylene-ethylene copolymer (HECO) are present, these components are preferably additives.

[0146] Those skilled in the art will be able to select appropriate additives known in the art.

[0147] Preferably, the additives are selected from pigments, antioxidants, UV stabilizers, scratch inhibitors, release agents, acid removers, lubricants, antistatic agents, and mixtures thereof.

[0148] It should be understood that the amount of additives includes any carrier polymer used to introduce the additives into the polypropylene composition (PC'), i.e., the masterbatch carrier polymer. An example of such a carrier polymer is a polypropylene homopolymer in powder form.

[0149] The components will now be described in more detail.

[0150] Random multiphase propylene-ethylene copolymer (RAHECO')

[0151] The content of random multiphase propylene-ethylene copolymer (RAHECO') relative to the total weight of the polypropylene composition (PC') is 15.0 to 45.0 wt%, more preferably 20.0 to 40.0 wt%, and most preferably 25.0 to 35.0 wt%.

[0152] Random multiphase propylene-ethylene copolymer (RAHECO') comprises:

[0153] a1) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene-ethylene random copolymer; and

[0154] b1) Amorphous propylene-ethylene elastomer (E).

[0155] The melt flow rate (MFR2) of the random multiphase propylene-ethylene copolymer (RAHECO') measured according to ISO 1133 at 230°C and 2.16 kg is preferably 0.1 to 10.0 g / 10 min, more preferably 0.3 to 5.0 g / 10 min, and most preferably 0.5 to 2.0 g / 10 min.

[0156] The melting temperature (T0) of random multiphase propylene-ethylene copolymer (RAHECO') determined by differential scanning calorimetry (DSC) m The temperature is 130 to 155°C, more preferably 134 to 150°C, and most preferably 138 to 145°C.

[0157] Preferably, the crystalline matrix (M) of the random multiphase propylene-ethylene copolymer (RAHECO') does not contain substances produced by... 13 2,1-region defects as determined by C-NMR spectroscopy.

[0158] The absence of 2,1-region defects indicates that the random multiphase propylene-ethylene copolymer (RAHECO') was polymerized in the presence of a Ziegler-Natta catalyst.

[0159] Therefore, more preferably, the random multiphase propylene-ethylene copolymer (RAHECO') is polymerized in the presence of a Ziegler-Natta catalyst.

[0160] The ethylene content (C2 (total)) of the random multiphase propylene-ethylene copolymer (RAHECO') as determined by CRYSTEX QC analysis is preferably 3.0 to 15.0 wt%, more preferably 5.0 to 13.0 wt%, and most preferably 7.0 to 11.0 wt%.

[0161] The soluble fraction (SF) content of the random multiphase propylene-ethylene copolymer (RAHECO'), as determined by CRYSTEX QC analysis, is preferably 10 to 45 wt%, more preferably 13 to 35 wt%, and most preferably 16 to 25 wt%.

[0162] The ethylene content (C2(SF)) of the soluble fraction of the random multiphase propylene-ethylene copolymer (RAHECO') as determined by CRYSTEX QC analysis is preferably 17.0 to 60.0 wt%, more preferably 20.0 to 50.0 wt%, and most preferably 25.0 to 40.0 wt%.

[0163] The intrinsic viscosity (iV(SF)) of the soluble fraction of the random multiphase propylene-ethylene copolymer (RAHECO') as determined by CRYSTEX QC analysis is preferably 1.20 to 4.50 dL / g, more preferably 2.00 to 4.00 dL / g, and most preferably 2.40 to 3.40 dL / g.

[0164] The random multiphase propylene-ethylene copolymer (RAHECO') has a crystalline fraction (CF) content of 55 to 90 wt%, more preferably 65 to 87 wt%, and most preferably 75 to 84 wt%, as determined by CRYSTEX QC analysis.

[0165] The ethylene content (C2(CF)) of the crystalline fraction of the random multiphase propylene-ethylene copolymer (RAHECO') as determined by CRYSTEX QC analysis is preferably 1.0 to 8.0 wt%, more preferably 2.0 to 7.0 wt%, and most preferably 3.0 to 6.0 wt%.

[0166] The intrinsic viscosity (iV(CF)) of the crystalline fraction of the random multiphase propylene-ethylene copolymer (RAHECO') as determined by CRYSTEX QC analysis is preferably 1.20 to 4.50 dL / g, more preferably 2.00 to 4.00 dL / g, and most preferably 2.60 to 3.60 dL / g.

[0167] Furthermore, preferably, the intrinsic viscosity ratio (iV(SF) / iV(CF)) of the soluble fraction and the crystalline fraction, as measured by CRYSTEX QC analysis, is 0.50 to 2.00, more preferably 0.75 to 1.50, and most preferably 0.90 to 1.10.

[0168] Particularly preferably, the random multiphase propylene-ethylene copolymer (RAHECO') of the polypropylene composition (PC') of the surface layer and / or core layer is the same as the random multiphase propylene-ethylene copolymer (RAHECO) of the polypropylene composition (PC) of the sealing layer.

[0169] Multiphase propylene-ethylene copolymer (HECO)

[0170] The content of multiphase propylene-ethylene copolymer (HECO) relative to the total weight of the polypropylene composition (PC') is 55.0 to 85.0 wt%, more preferably 60.0 to 80.0 wt%, and most preferably 65.0 to 75.0 wt%.

[0171] Multiphase propylene-ethylene copolymer (HECO) comprises:

[0172] a2) A crystalline matrix (M), wherein the crystalline matrix (M) is a propylene homopolymer; and

[0173] b2) Amorphous propylene-ethylene elastomer (E).

[0174] The melt flow rate (MFR2) of the multiphase propylene-ethylene copolymer (HECO) measured according to ISO 1133 at 230°C and 2.16 kg is preferably 0.1 to 6.0 g / 10 min, more preferably 0.3 to 3.0 g / 10 min, and most preferably 0.5 to 1.0 g / 10 min.

[0175] The melting temperature (To) of multiphase propylene-ethylene copolymer (HECO) determined by differential scanning calorimetry (DSC) m The temperature is 150 to 170°C, more preferably 155 to 168°C, and most preferably 160 to 167°C.

[0176] Preferably, the crystalline matrix (M) of the multiphase propylene-ethylene copolymer (HECO) does not contain substances produced by... 13 2,1-region defects were determined by C-NMR spectroscopy.

[0177] The absence of 2,1-region defects indicates that the multiphase propylene-ethylene copolymer (HECO) was polymerized in the presence of a Ziegler-Natta catalyst.

[0178] Therefore, more preferably, the multiphase propylene-ethylene copolymer (HECO) is polymerized in the presence of a Ziegler-Natta catalyst.

[0179] The ethylene content (C2 (total)) of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 3.0 to 15.0 wt%, more preferably 4.0 to 12.0 wt%, and most preferably 5.0 to 9.0 wt%.

[0180] The soluble fraction (SF) content of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 5 to 30 wt%, more preferably 10 to 25 wt%, and most preferably 12 to 20 wt%.

[0181] The ethylene content (C2(SF)) of the soluble fraction of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 17.0 to 60.0 wt%, more preferably 20.0 to 50.0 wt%, and most preferably 30.0 to 45.0 wt%.

[0182] The intrinsic viscosity (iV(SF)) of the soluble fraction of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 1.20 to 4.50 dL / g, more preferably 1.70 to 4.00 dL / g, and most preferably 2.20 to 3.30 dL / g.

[0183] The crystalline fraction (CF) content of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 70 to 95 wt%, more preferably 75 to 90 wt%, and most preferably 80 to 88 wt%.

[0184] The ethylene content (C2(CF)) of the crystalline fraction of the first multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 1.0 to 8.0 wt%, more preferably 2.0 to 6.0 wt%, and most preferably 2.5 to 5.0 wt%.

[0185] The intrinsic viscosity (iV(CF)) of the crystalline fraction of the multiphase propylene-ethylene copolymer (HECO), as determined by CRYSTEX QC analysis, is preferably 1.20 to 4.50 dL / g, more preferably 2.00 to 4.00 dL / g, and most preferably 2.50 to 3.50 dL / g.

[0186] Furthermore, preferably, the intrinsic viscosity ratio (iV(SF) / iV(CF)) of the soluble fraction and the crystalline fraction, as measured by CRYSTEX QC analysis, is 0.50 to 2.00, more preferably 0.75 to 1.50, and most preferably 0.90 to 1.10.

[0187] Multilayer film

[0188] As described above, the multilayer film (F) comprises the following layers in a given order:

[0189] (A) Surface layer;

[0190] (B) Core layer; and

[0191] (C) Sealing layer.

[0192] Although other layers may be present, it is preferred that any other layer (if present) be between the surface layer (A) and the core layer (B), or between the core layer (B) and the sealing layer (C), and most preferably between the surface layer (A) and the core layer (B).

[0193] Particularly preferably, there are no other layers, that is, the multilayer film (F) is a 3-layer film consisting of layer (A), layer (B) and layer (C).

[0194] Preferably, the thickness of the multilayer film (F) is 20 to 150 μm, more preferably 30 to 100 μm, and most preferably 50 to 80 μm.

[0195] Preferably:

[0196] a) The thickness of the surface layer is 10% to 40% of the total thickness of the multilayer film (F);

[0197] b) The thickness of the core layer is 30% to 70% of the total thickness of the multilayer film (F); and

[0198] c) The thickness of the sealing layer is 10% to 40% of the total thickness of the multilayer film (F).

[0199] Further preferred:

[0200] a) The thickness of the surface layer is 15% to 35% of the total thickness of the multilayer film (F);

[0201] b) The core layer thickness is 35% to 65% of the total thickness of the multilayer film (F); and

[0202] c) The thickness of the sealing layer is 15% to 35% of the total thickness of the multilayer film (F).

[0203] Particularly preferred:

[0204] a) The thickness of the surface layer is 20% to 30% of the total thickness of the multilayer film (F);

[0205] b) The core layer thickness is 40% to 60% of the total thickness of the multilayer film (F); and

[0206] c) The thickness of the sealing layer is 20% to 30% of the total thickness of the multilayer film (F).

[0207] Preferably, the tensile modulus (TM-MD) in the machine direction of the multilayer film (F), as measured according to ISO 527-3, is 700 to 1500 MPa, more preferably 800 to 1300 MPa, and most preferably 850 to 1100 MPa.

[0208] Preferably, the tensile modulus (TM-TD) in the transverse direction of the multilayer film (F), as measured according to ISO 527-3, is 700 to 1500 MPa, more preferably 800 to 1300 MPa, and most preferably 850 to 1100 MPa.

[0209] Preferably, the dart impact strength (DDI) of the multilayer film (F) measured according to ISO 7765-1 is 100 to 600 g, more preferably 200 to 500 g, and most preferably 300 to 400 g.

[0210] Preferably, the haze value of the multilayer film (F) as measured according to ASTM D1003 is 10% to 40%, more preferably 15% to 35%, and most preferably 20% to 30%.

[0211] Preferably, the sealing initiation temperature (SIT) of the multilayer film (F) measured according to the method specified in the measurement method is 115 to 130°C, more preferably 119 to 128°C, and most preferably 122 to 127°C.

[0212] Preferably, the pre-sterilization sealing strength (bs) of the multilayer film (F), as measured according to the method specified in the measurement method, is 15 to 40 N / mm, more preferably 18 to 35 N / mm, and most preferably 20 to 30 N / mm.

[0213] Preferably, the sterile sealing strength (as) of the multilayer film (F), as measured according to the method specified in the measurement method, is 20 to 45 N / mm, more preferably 23 to 40 N / mm, and most preferably 25 to 35 N / mm.

[0214] Furthermore, preferably, the post-sterilization sealing strength (as) of the multilayer film (F) is at least 92%, more preferably at least 95%, and most preferably at least 98% of the pre-sterilization sealing strength (bs), both of which are measured according to the method specified in the measurement method.

[0215] The seal strength (as) after sterilization is typically no more than 125% of the seal strength (bs) before sterilization.

[0216] Example

[0217] 1. Measurement Method

[0218] Unless otherwise defined, the following definitions of terms and methods apply to the general description of the invention above, including the claims, and to the embodiments described below.

[0219] Quantitative analysis of microstructure using NMR spectroscopy

[0220] Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the comonomer and regional defect content of polymers.

[0221] Recordings were performed at 400.15 MHz and 100.62 MHz using a Bruker Avance III 400 NMR spectrometer. 1 H and 13 Quantitative analysis of C in solution state13 C{ 1 ¹H NMR spectra. All spectra were performed at 125 °C. 13 Recording was performed using a C-optimized 10mm extended temperature probe, with nitrogen used for all pneumatic devices. Approximately 200 mg of material was dissolved with chromium acetylacetone (Cr(acac)3) in approximately 3 mL of 1,2-tetrachloroethane-d2 (TCE-d2) to obtain a 65 mM relaxant solution in solvent {singh09}. 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. After insertion of the magnet, the tube was rotated at a frequency of 10 Hz. This setup was chosen primarily for the high resolution and quantitative requirements necessary for accurate ethylene content quantification. Standard single-pulse excitation without NOE was used, with optimized tip angle, 1-second cycle delay, and a double-layer WALTZ16 decoupling scheme {zhou07, busico07}. A total of 6144 (6 k) transients were acquired for each spectrum.

[0222] Quantitative 13 C{ 1 The ¹H NMR spectra were processed, integrated, and the relevant quantitative properties were determined by integration using a proprietary computer program. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at a chemical shift of 30.00 ppm using the solvent. This method allows for comparable references even in the absence of this structural unit.

[0223] Characteristic signals {wang00, cheng84, randall89} corresponding to ethylene incorporation were observed.

[0224] Using the method {wang00} of Wang et al., through the... 13 C{ 1 Integrating multiple signals across the entire spectral region of the H spectrum allows for the quantification of comonomer fractions. This method was chosen due to its robustness and ability to account for regional defects when needed. Slight adjustments were made to the integration region to improve applicability across the entire range of comonomer content encountered.

[0225] For systems where only isolated ethylene is observed in the PPEPP sequence, the method of Wang et al. was modified to reduce the influence of non-zero integrals from sites that are known to be absent. This method reduces the overestimation of ethylene content in such systems and achieves this by reducing the number of sites used to determine the absolute ethylene content. Using this set of sites, the corresponding integral equation becomes:

[0226] p S =I A +(0.5*I B )

[0227] p T =I D +I F +I D

[0228] p = (p S +p T ) / 2

[0229] e = 0.5 * (I H +(0.5*I B fE = e / (e+p)

[0230] Use the same symbols as those used in the paper {wang00} by Wang et al.

[0231] Calculate the molar percentage of comonomer incorporated from the molar fraction:

[0232] E[mol%]=100*fE

[0233] Calculate the weight percentage of comonomer incorporated from the mole fraction:

[0234] E[wt%]=100*(fE*28.06) / ((fE*28.06)+((1-fE)*42.08))

[0235] Characteristic signals {resconi00, wang00} corresponding to regional defects were observed. The presence of two methyl sites at 17.7 and 17.2 ppm indicates the existence of isolated 2,1-erythromorphic regional defects, confirmed by other characteristic sites. The 2,1-regional defects near the ethylene unit are indicated by two inequivalent Sαβ signals at 34.9 and 34.7 ppm and a Tγγ signal at 34.1 ppm, respectively.

[0236] Using respectively located at 17.7 (I e8 ) and 17.4(I e6 The amount of isolated 2,1-erythromorphic defects is quantified by the average integral of two characteristic methyl sites at ppm. 21e孤立 ):

[0237] P 21e孤立 =(I e6 +I e8 ) / 2

[0238] Using the methine site at 34.1 ppm (I Tγγ Quantitatively measure the amount of defects in the 2,1 region adjacent to ethylene (P) E21 ):

[0239] P E21 =ITγγ

[0240] Based on the methyl region (I) between 23.0 and 19.9 ppm CH3 ) for total propylene (P 总 Quantification was performed, and corrections were made for sites in this region unrelated to propylene insertion. Methyl Pγγ, generated by defects in the 2,1 region adjacent to ethylene, already exists in I... CH3 :

[0241] P 总 =I CH3 +2*P 21e孤立

[0242] The isolated 2,1-red type region defect (P) 21e孤立 Multiply by 2 to take into account the two (2) propylene units in the 2,1-red zone defect.

[0243] The molar percentage of isolated 2,1-erythromorphic defects relative to all propylene was quantified as follows:

[0244] [21e]mol% = 100*P 21e孤立 / P 总

[0245] The molar percentage of defects in the 2,1 region adjacent to ethylene was quantified relative to all propylene:

[0246] [E21]mol% = 100*P E21 / P 总

[0247] The total number of defects 2.1 is quantified as follows:

[0248]

[21] mol% = [21e] + [E21]

[0249] No characteristic signal {resconi00} was observed corresponding to other types of regional defects (2,1-Su type, 3,1 insertion).

[0250]

[0251] CRYSTEX QC Analysis

[0252] Methods for crystalline fractionation and soluble fractionation

[0253] The crystalline fraction (CF) and soluble fraction (SF) of polypropylene (PP) compositions, as well as the comonomer content and intrinsic viscosity of each fraction, were analyzed using a CRYSTEX Polymer Char instrument (Valencia, Spain). Detailed information on the techniques and methods can be found in the literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer & Markus Gahleitner (2020) Rapid characterization of high-impact ethylene-propylene copolymer composition by crystallization extraction separation: comparison to standard separation methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596).

[0254] The crystalline and amorphous fractions were separated by a temperature cycle of dissolution in 1,2,4-trichlorobenzene at 160 °C, crystallization at 40 °C, and redissolution at 160 °C. Quantification of SF and CF, as well as determination of ethylene content (C2), were achieved using an integrated infrared detector (IR4), and an online dual-capillary viscometer was used for intrinsic viscosity (IV) determination.

[0255] The IR4 detector is a multi-wavelength detector that measures two different wavelengths (CH3 stretching vibration, centered at approximately 2960 cm⁻¹). -1 (at the location) and CH stretching vibration (2700-3000cm) -1 The infrared absorbance of the IR4 detector is used to determine the concentration and ethylene content of ethylene-propylene copolymers. The IR4 detector is calibrated with a series of eight EP copolymers, with known ethylene contents ranging from 2 wt% to 69 wt% (via...). 13 (Measured by C-NMR), the concentration of each copolymer ranged from 2 to 13 mg / mL. To simultaneously correct for both concentration and ethylene content (for various polymer concentrations that may occur in Crystex analysis), the following calibration equation was used:

[0256] Concentration = a + b * Abs(CH) + c * (Abs(CH)) 2 +d*Abs(CH3)+e*(Abs(CH3) 2 +f*Abs(CH)*Abs(CH3) (Equation 1)

[0257] CH3 / 1000C=a+b*Abs(CH)+c*Abs(CH3)+d*(Abs(CH3) / Abs(CH))+e*(Abs(CH3) / Abs(CH)) 2 (Equation 2)

[0258] The constants a to e in Equation 1 and the constants a to f in Equation 2 are determined by using least squares regression analysis.

[0259] Use the following relationship to convert CH3 / 1000C to ethylene content (wt%):

[0260] wt% (ethylene in EP copolymer) = 100 - CH3 / 1000TC * 0.3 (Equation 3)

[0261] The amounts of the soluble fraction (SF) and crystalline fraction (CF) were correlated, respectively, to the amounts of the "cold xylene soluble" (XCS) fraction and the cold xylene insoluble (XCI) fraction, determined by standard gravimetric method according to ISO 16152, using XS calibration curves. XS calibration was achieved by testing various EP copolymers with XS contents ranging from 2 to 31 wt%. The determined XS calibration curves were linear.

[0262] wt%XS = 1.01 * wt%SF (Equation 4)

[0263] The intrinsic viscosity (IV) of the parent EP copolymer and its soluble and crystalline fractions was determined using an online dual-capillary viscometer and correlated to the corresponding IV obtained according to standard methods in decahydronaphthalene according to ISO 1628-3. Calibration was performed using various EP / PP copolymers with IV = 2-4 dL / g. The determined calibration curves were linear.

[0264] IV(dL / g)=a*Vsp / c (Equation 5)

[0265] Weigh the sample to be analyzed at a concentration of 10 to 20 mg / mL. To avoid injecting gels and / or polymers (e.g., PET and PA) that are insoluble in TCB at 160°C, load the weighed sample into a stainless steel mesh MW 0077 / D 0.05 mm.

[0266] After autofilling vials with 1,2,4-TCB containing 250 mg / L of the antioxidant 2,6-tert-butyl-4-methylphenol (BHT), the sample was dissolved at 160°C until completely dissolved, typically for 60 minutes with a stirring speed of 400 rpm. To prevent sample degradation, the polymer solution was covered with a nitrogen atmosphere during the dissolution process.

[0267] A predetermined volume of sample solution is injected into a column packed with an inert support, where crystallization and separation of the soluble and crystalline fractions are carried out. This process is repeated twice. During the first injection, the entire sample is measured at high temperature to determine the IV [dL / g] and C2 [wt%] of the PP composition. During the second injection, the soluble fraction (at low temperature) and crystalline fraction (at high temperature) are measured during the crystallization cycle (wt% SF, wt% C2, IV).

[0268] melt flow rate

[0269] Melt flow rate (MFR) was determined according to ISO 1133, with units of g / 10 min. MFR indicates the flowability of a polymer, and thus its processability. A higher melt flow rate generally corresponds to a lower polymer viscosity. The MFR² of polypropylene was determined at 230°C and a load of 2.16 kg.

[0270] density:

[0271] Density was measured according to ISO 1183-187. Samples were prepared by compression molding according to ISO 1872-2:2007.

[0272] Xylene-soluble fraction at room temperature (XCS, wt%): The amount of polymer soluble in xylene is determined at 25°C according to ISO 16152 (5th edition; 2005-07-01).

[0273] DSC analysis, melting temperature (T) m ) and heat of fusion (H f ), crystallization temperature (T) c ) and heat of crystallization (Hc):

[0274] Samples ranging from 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 temperature range of -30 to +225 °C at a scan rate of 10 °C / min, using a hot / cold / hot cycle. Crystallization temperature (T...) c ) and crystallization enthalpy (H c The melting temperature (T) is determined by the cooling step, while the melting temperature (T) is determined by the cooling step. m ) and enthalpy of fusion (H m The result is determined by the second heating step.

[0275] DDI

[0276] ISO 7765-1:1988 / Method A

[0277] This test method involves determining the energy that causes membrane failure under specified conditions, namely, impacting the specimens from a predetermined height that would cause 50% of the test specimens to fail via free-fall darts (step method A). During the test, a uniform increment of impactor mass is used, and after each specimen is tested, the impactor weight is reduced or increased by the uniform increment based on the observed result (failure or no failure) of the specimen.

[0278] Standard conditions :

[0279] Adjustment time: >96 hours

[0280] Test temperature: 23℃

[0281] Dart material: phenolic resin

[0282] Dart diameter: 38mm

[0283] Drop height: 660mm

[0284] result :

[0285] Impact failure mass [g]

[0286] Minimum thickness [mm]

[0287] Maximum thickness [mm]

[0288] The thickness of the membrane described in the "Examples" below was tested according to ISO 7765-1:1988 / Method A and reported in grams (g).

[0289] The DDI per unit thickness (in g / μm) is calculated by dividing the DDI (in g) by the film thickness (in μm).

[0290] Haze

[0291] According to ASTM D1003-00, haze was measured directly on the multilayer film prepared in the experimental section.

[0292] Sealing range test (SIT, maximum sealing force, and SET)

[0293] This method is used to determine the sealing window (sealing temperature range) of the membrane. The procedure is similar to the hot tack test and is performed on the same machine. Compared to hot tack, the determined sealing range corresponds to the strength of the seal after cooling (delay time 30 s). The conditions used are as follows:

[0294] • Sealing time (1 second)

[0295] • Sealing pressure (0.4 N / mm) 2 )

[0296] • Delay time (30s)

[0297] • Fixture separation speed (42mm / s)

[0298] Sealing range = (Sealing start temperature to sealing end temperature)

[0299] The test results provide a quantitative and useful indication of the membrane seal strength and indicate the temperature range for optimal sealing.

[0300] The lower limit (Seal Initiation Temperature - SIT) is the sealing temperature at which an average sealing force of 5 N is measured (i.e., the lowest temperature at which this force is measured). The upper limit (Seal End Temperature - SET) is determined as the first sealing temperature at which at least two samples show a burn-through failure mode. The maximum sealing force corresponds to the highest sealing force measured.

[0301] By default, the temperature interval is set to 5°C, but when the curve shows a sharp increase or decrease in force between two temperature steps, the temperature interval can be reduced to 1°C. This is done to display better curve characteristics.

[0302] Unlike ASTM F1921-12, the test parameters for sealing pressure, cooling time, and test speed have been modified. The force / temperature profile is measured continuously until membrane thermal failure. In addition to the failure mode assessments described in the standard, other failure modes are used.

[0303] Sealing strength

[0304] The heat-sealing test was conducted on at least three membrane specimens, each 85 mm wide and 200 mm long, cut longitudinally. A 5 mm x 150 mm Teflon-coated steel heating rod was used, with the temperature set to 110 °C. Two membranes were sealed by positioning, one on top of the other, for 0.5 s at a pressure of 0.67 N / mm². 2 The resulting sealed area was 85 mm x 5 mm. The specimens were then conditioned for 7 days (±24 hours) at 23°C (±2°C) / 50% RH (±10%). Ten 15 mm wide specimens were cut and tested on a general-purpose testing machine (Zwick Z005) in tensile mode at 23°C (±2°C) / 50% RH (±10%). The clamping distance used was 100 mm, and the testing speed was 200 mm / min. The yield strength and maximum force of each test specimen were measured.

[0305] Basic seal:

[0306] • Membrane width: 85mm

[0307] • Membrane length: >200mm

[0308] • Sealing joint width: 5mm

[0309] • Sealing temperature: 110℃

[0310] • Sealing pressure: 0.67 N / mm 2

[0311] • Sealing time: 0.5s

[0312] • Sealing claws: coated with Teflon

[0313] adjust:

[0314] • Adjustment time: 23℃ (±2℃) / 50% RH (±10%), 7 days (±24 hours)

[0315] Heat seal strength:

[0316] • Test temperature: 23℃ (±2℃) / 50% RH (±10%)

[0317] • Sample width: 15mm

[0318] • Grip distance: 100mm

[0319] • Test speed: 200mm / min

[0320] • Testing equipment: Universal testing machine

[0321] Tensile modulus

[0322] The tensile modulus in the longitudinal and transverse directions of the multilayer films produced in the experimental section was determined according to ISO 527-3 at 23°C. The test was conducted at a crosshead speed of 1 mm / min.

[0323] Steam sterilization

[0324] Steam sterilization was performed using a Systec D-Series machine (Systec Corporation, USA). Samples were heated from 23°C at a rate of 5°C / min. After holding at 130°C for 30 minutes, they were immediately removed from the steam sterilizer, stored at room temperature, and then subjected to further processing or testing.

[0325] 2. Example

[0326] 2.1. Synthesis of multiphase propylene-ethylene copolymers (RAHECO, HECO1, and HECO2)

[0327] For the polymerization process of HECO2, the Ziegler-Natta type catalyst used in the invention embodiment of WO2016 / 06646A1 is used to prepolymerize vinylcyclohexane to achieve nucleation with poly(vinylcyclohexane).

[0328] Nucleation by prepolymerization with vinylcyclohexane is described in detail in EP290256B1 and EP2960279B1.

[0329] For the polymerization processes of RAHECO and HECO1, the same catalyst is used, except that prepolymerization with vinylcyclohexane is not carried out (i.e., only the catalyst used in the inventive embodiment of WO 2016 / 06646A1 is used).

[0330] The catalyst system defined above is used in combination with triethylaluminum (TEAL) (as a co-catalyst) and dicyclopentadienyl-dimethoxysilane (donor D) (as an external donor).

[0331] The subsequent polymerization was carried out under the following conditions.

[0332] Table 1: Polymerization conditions of multiphase propylene-ethylene copolymers

[0333]

[0334] The matrices of RAHECO, HECO1, and HECO2 do not contain 2,1-region defects.

[0335] In a Coperion ZSK 47 co-rotating twin-screw extruder, at 220°C, RAHECO was compounded with the following components: 0.19 wt% antioxidant blend (Irganox B215FF from BASF, Germany, a 1:2 mixture of the following components: pentaerythritol tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, CAS No. 6683-19-8; tris(2,4-di-tert-butylphenyl) phosphite, CAS No. 31570-04-4); and 0.05 wt% stearic acid Ca (CAS No. 1592-23-0, purchased from Faci, Italy).

[0336] In a Coperion ZSK 47 co-rotating twin-screw extruder, HECO1 was compounded with the following components at 220°C: 0.15 wt% pentaerythritol-tetra(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)-propionate (Irganox 1010, purchased from BASF, Germany, CAS No. 6683-19-8); and 0.05 wt% stearic acid Ca (CAS No. 1592-23-0, purchased from Faci, Italy).

[0337] In a Coperion ZSK 47 co-rotating twin-screw extruder, HECO2 was compounded with the following components at 220°C: 0.15 wt% pentaerythritol-tetra(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1010, purchased from BASF, Germany, CAS No. 6683-19-8); 0.10 wt% tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168, purchased from BASF, Germany, CAS No. 31570-04-4); 0.03 wt% synthetic hydrotalcite (Hycite 713, purchased from BASF, Germany, CAS No. 11097-59-9); and 0.05 wt% nucleating agent (Hyperform HPN-20E, purchased from Milliken, USA, CAS No. 491589-22-1 for the major component).

[0338] 2.2. Propylene-ethylene random copolymers (R-PP1 and R-PP2)

[0339] The catalysts used in the polymerization of propylene-ethylene random copolymers R-PP1 and R-PP2 were prepared as follows:

[0340] Metallocene MC1 (racemic-trans-dimethylsilanediyl(2-methyl-4-phenyl-5-methoxy-6-tert-butyl-indenyl)(2-methyl-4-(4-tert-butylphenyl)indenyl]zirconium dichloride) has been synthesized as described in WO 2013 / 007650.

[0341] According to Catalyst 3 of WO 2015 / 11135, a catalyst was prepared using a catalyst system of metallocene MC1, MAO, and triphenylmethyltetra(pentafluorophenyl)borate, under the following conditions: the surfactant was 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)-1-propanol.

[0342] Table 2: Polymerization conditions of propylene-ethylene random copolymers

[0343]

[0344] In a Coperion ZSK 47 co-rotating twin-screw extruder, R-PP1 was compounded with the following components at 220°C: 0.05 wt% pentaerythritol-tetra(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1010, purchased from BASF, Germany, CAS No. 6683-19-8); 0.05 wt% tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168, purchased from BASF, Germany, CAS No. 31570-04-4); 0.03 wt% synthetic hydrotalcite (Hycite 713, purchased from BASF, Germany, CAS No. 11097-59-9); and 0.08 wt% nucleating agent (ADK Stab NA-71, purchased from Adeka, Germany, CAS No. 85209-93-4 for the major component).

[0345] In a Coperion ZSK 47 co-rotating twin-screw extruder, R-PP2 was compounded with the following components at 220°C: 0.20 wt% crodamide (Crodamide ER beads, purchased from Croda International, UK, CAS No. 112-84-5); 0.18 wt% amorphous silica (Sylobloc 45B, purchased from Grace GmbH, Germany, CAS No. 7631-86-9); and 0.10 wt% antioxidant blend (Irganox from BASF, Germany). B215FF is a 1:2 mixture of the following components: pentaerythritol tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, CAS No. 6683-19-8; tris(2,4-di-tert-butylphenyl)phosphite, CAS No. 31570-04-4); and 0.04 wt% stearic acid Ca (purchased from Faci, Italy, CAS No. 1592-23-0) and 2.0 wt% propylene homopolymer described in IE2 of Table 1 of EP3184 587.

[0346] Furthermore, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane was used to perform viscosity-reducing cracking on R-PP2, achieving an MFR2 of 11.0 g / 10 min. During the viscosity-reducing cracking process, XCS and T... m The defect content in C2 (total) and 2,1-region remained unchanged.

[0347] 2.3. Blending of the multilayer film of the present invention and the comparative multilayer film

[0348] The compositions for each layer were prepared by compounding at 220°C in a Coperion ZSK40 co-rotating twin-screw extruder according to the formulations shown in Table 3.

[0349] The three-layer film was produced on Collin's laboratory-scale blown film production line, with a film thickness of 60 μm, a BUR ratio of 1:2.5, and a melt temperature of 210°C. The film thickness distribution was 25% for the surface layer, 50% for the core layer, and 25% for the sealing layer.

[0350] Table 4 shows the performance of the compositions of the present invention and the comparative compositions.

[0351] Table 3: Formulations of the embodiments and comparative examples of the present invention

[0352]

[0353] Table 4: Performance of the multilayer film of the present invention and the comparative multilayer film

[0354]

[0355] As shown in Table 4, the multilayer film of the present invention exhibits a significantly reduced SIT value and a significantly improved sealing strength before and after sterilization, while maintaining acceptable mechanical and optical properties. Furthermore, the sealing strength after sterilization is higher than that before sterilization in all cases, while the comparative example shows a decrease in sealing strength.

Claims

1. A multilayer film (F) comprising the following layers in the given order: (A) a skin layer, which comprises at least 90 wt% of polypropylene or a mixture of polypropylenes, based on the total weight of the skin layer; (B) a core layer, which comprises at least 90 wt% of polypropylene or a mixture of polypropylenes, based on the total weight of the core layer; and (C) a seal layer, which comprises at least 90 wt% of a polypropylene composition (PC), based on the total weight of the seal layer, the polypropylene composition comprising: i) 20 to 70 wt% of a random heterophasic propylene-ethylene copolymer (RAHECO), based on the total weight of the polypropylene composition (PC), having a melt flow rate (MFR2) measured according to ISO 1133 at 230 °C and 2.16 kg of 0.1 to 10.0 g / 10 min, the random heterophasic propylene-ethylene copolymer (RAHECO) comprising: a) a crystalline matrix (M) which is a propylene-ethylene random copolymer; and b) an amorphous propylene-ethylene elastomer (E); ii) 10 to 50 wt% of a first propylene-ethylene random copolymer (R-PP1), based on the total weight of the polypropylene composition (PC), having a melt flow rate (MFR2) measured according to ISO 1133 at 230 °C and 2.16 kg of 1.0 to 6.0 g / 10 min; and iii) 10 to 50 wt% of a second propylene-ethylene random copolymer (R-PP2), based on the total weight of the polypropylene composition (PC), having a melt flow rate (MFR2) measured according to ISO 1133 at 230 °C and 2.16 kg of 7.0 to 20 g / 10 min; wherein the combined amount of the random heterophasic propylene-ethylene copolymer (RAHECO), the first propylene-ethylene random copolymer (R-PP1) and the second propylene-ethylene random copolymer (R-PP2) being at least 90 wt% relative to the total weight of the polypropylene composition (PC).

2. The multilayer film (F) according to claim 1, wherein The random heterophasic propylene-ethylene copolymer (RAHECO) has one or more of the following properties: a) a soluble fraction (SF) content of 10 to 45 wt%, a crystalline fraction (CF) content of 55 to 90 wt%, both measured by CRYSTEX QC analysis; b) a melting temperature (Tm) of 130 to 155 °C, measured by differential scanning calorimetry (DSC); and m b) a melting temperature (Tm) of 130 to 155 °C, measured by differential scanning calorimetry (DSC); and c) the crystallization matrix (M) does not contain by 13 2,1 regio-defects determined by C-NMR spectroscopy.

3. The multilayer film (F) according to claim 1 or 2, wherein The random heterophasic propylene-ethylene copolymer (RAHECO) has one or more of the following properties: a) an ethylene content (C2(total)) of 3.0 to 15.0 wt%, measured by CRYSTEX QC analysis; b) an ethylene content of the soluble fraction (C2(SF)) of 17.0 to 60.0 wt%, measured by CRYSTEX QC analysis; c) the ethylene content (C2(CF)) of the crystalline fraction measured by CRYSTEX QC analysis is in the range of 1.0 to 8.0 wt%.

4. The multilayer film (F) according to claim 1 or 2, wherein The random heterophasic propylene-ethylene copolymer (RAHECO) has one or more of the following properties: a) the intrinsic viscosity iV(SF) of the soluble fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g; b) the intrinsic viscosity iV(CF) of the crystalline fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g; c) the intrinsic viscosity ratio iV(SF) / iV(CF) measured by CRYSTEX QC analysis is in the range of 0.50 to 2.

00.

5. The multilayer film (F) according to claim 1 or 2, wherein The first propylene-ethylene random copolymer (R-PP1) has one or more of the following properties: a) by quantification of the ethylene content (C2) measured by C-NMR spectroscopy in the range of 1.0 to 5.5 wt%; and / or 13 the ethylene content (C2) measured by C-NMR spectroscopy is in the range of 1.0 to 5.5 wt%; and / or b) the xylene cold soluble (XCS) content measured according to ISO 16152 is in the range of 0.2 to 5.0 wt%; c) a melting temperature (Tm) of 130 to 155 °C, measured by differential scanning calorimetry (DSC); m c) a melting temperature (Tm) of 130 to 155 °C, measured by differential scanning calorimetry (DSC); d) a crystallization temperature (Tc) of 110 to 125 °C, measured by differential scanning calorimetry (DSC); c d) a crystallization temperature (Tc) of 110 to 125 °C, measured by differential scanning calorimetry (DSC); e) by 13 The content of 2,1 -regio defects was determined by C-NMR spectroscopy to be 0.05 to 1.40 mol%.

6. The multilayer film (F) according to claim 1 or 2, wherein The second propylene-ethylene random copolymer (R-PP2) has one or more of the following properties: a) by quantification of the ethylene content (C2) measured by C-NMR spectroscopy in the range of 1.0 to 5.5 wt%; and / or 13 the ethylene content (C2) measured by C-NMR spectroscopy is in the range of 1.0 to 5.5 wt%; and / or b) the xylene cold soluble (XCS) content measured according to ISO 16152 is in the range of 0.2 to 5.0 wt%; c) a melting temperature (Tm) measured by differential scanning calorimetry (DSC) of 125 to 145 °C; m c) a melting temperature (Tm) measured by differential scanning calorimetry (DSC) of 125 to 145 °C; d) a crystallization temperature (Tc) of 100 to 120 °C measured by differential scanning calorimetry (DSC); c d) a crystallization temperature (Tc) of 100 to 120 °C measured by differential scanning calorimetry (DSC); e) by 13 The content of 2,1 -regio defects was determined by C-NMR spectroscopy to be 0.05 to 1.40 mol%.

7. The multilayer film (F) according to claim 1 or 2, wherein: a) the thickness of the skin layer is in the range of 10% to 40% of the total thickness of the multilayer film (F); b) the thickness of the core layer is in the range of 30% to 70% of the total thickness of the multilayer film (F); and c) the thickness of the seal layer is in the range of 10% to 40% of the total thickness of the multilayer film (F).

8. The multilayer film (F) according to claim 1 or 2, wherein At least one of the skin layer and the core layer comprises at least 90 wt% of a polypropylene composition (PC'), the polypropylene composition (PC') comprising: i) 15 to 45 wt% of a random heterophasic propylene-ethylene copolymer (RAHECO'), based on the total weight of the polypropylene composition (PC'), having a melting temperature (Tm) in the range of 130 to 155 °C, measured by differential scanning calorimetry (DSC), m ) in the range of 130 to 155 °C, measured by differential scanning calorimetry (DSC), The random heterophasic propylene-ethylene copolymer (RAHECO') comprises: a1) a crystalline matrix (M) which is a propylene-ethylene random copolymer; and b1) an amorphous propylene-ethylene elastomer (E); and ii) 55 to 85 wt% of a heterophasic propylene-ethylene copolymer (HECO), based on the total weight of the polypropylene composition (PC'), having a melting temperature (Tm) in the range of 150 to 170 °C, measured by differential scanning calorimetry (DSC), m as defined above, and The heterophasic propylene-ethylene copolymer (HECO) comprises: a2) a crystalline matrix (M) which is a propylene homopolymer; and b2) an amorphous propylene-ethylene elastomer (E), The combined amount of the random heterophasic propylene-ethylene copolymer (RAHECO') and the heterophasic propylene-ethylene copolymer (HECO) is at least 90 wt% relative to the total weight of the polypropylene composition (PC').

9. The multilayer film (F) according to claim 8, wherein The propylene-ethylene random copolymer contains no more than 0.1 wt% of 2,1 -regio defects as determined by quantitative 13 2,1 -regio defects determined by C-NMR spectroscopy.

10. The multilayer film (F) according to claim 8, wherein The propylene homopolymer does not contain more than 0.1 wt% of 13 2,1 regiodefects determined by C-NMR spectroscopy.

11. The multilayer film (F) according to claim 8, wherein The random heterophasic propylene-ethylene copolymer (RAHECO') has one or more of the following properties: a) the melt flow rate (MFR2) measured according to ISO 1133 at 230 °C and 2.16 kg is in the range of 0.1 to 10.0 g / 10min; b) the soluble fraction (SF) content is in the range of 10 to 45 wt% and the crystalline fraction (CF) content is in the range of 55 to 90 wt%, both measured by CRYSTEX QC analysis; c) the ethylene content (C2(total)) measured by CRYSTEX QC analysis is in the range of 3.0 to 15.0 wt%. d) the ethylene content (C2(SF)) of the soluble fraction measured by CRYSTEX QC analysis is in the range of 17.0 to 60.0 wt%; e) the ethylene content (C2(CF)) of the crystallized fraction measured by CRYSTEX QC analysis is in the range of 1.0 to 8.0 wt%; f) the intrinsic viscosity iV(SF) of the soluble fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g; g) the intrinsic viscosity iV(CF) of the crystallized fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g; h) the intrinsic viscosity ratio iV(SF) / iV(CF) measured by CRYSTEX QC analysis is in the range of 0.50 to 2.

00.

12. The multilayer film (F) according to claim 8, wherein The heterophasic propylene-ethylene copolymer (HECO) has one or more of the following properties: a) the melt flow rate (MFR2) measured according to ISO 1133 at 230 °C and 2.16 kg is in the range of 0.1 to 6.0 g / 10min; b) the soluble fraction (SF) content is in the range of 5 to 30 wt%, the crystallized fraction (CF) content is in the range of 70 to 95 wt%, both measured by CRYSTEX QC analysis; c) the ethylene content (C2(total)) measured by CRYSTEX QC analysis is in the range of 3.0 to 15.0 wt%; d) the ethylene content (C2(SF)) of the soluble fraction measured by CRYSTEX QC analysis is in the range of 17.0 to 60.0 wt%; e) the ethylene content (C2(CF)) of the crystallized fraction measured by CRYSTEX QC analysis is in the range of 1.0 to 8.0 wt%; f) the intrinsic viscosity iV(SF) of the soluble fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g; g) the intrinsic viscosity iV(CF) of the crystallized fraction measured by CRYSTEX QC analysis is in the range of 1.20 to 4.50 dL / g.

13. The multilayer film (F) according to claim 8, wherein The random heterophasic propylene-ethylene copolymer (RAHECO’) is identical to the random heterophasic propylene-ethylene copolymer (RAHECO).

14. The multilayer film (F) according to claim 1 or 2, wherein The multilayer film (F) has one or more of the following properties:

15. The multilayer film (F) according to claim 1 or 2, wherein a) the tensile modulus in machine direction (TM-MD) measured according to ISO 527-3 is in the range of 700 to 1500 MPa; b) the tensile modulus in transverse direction (TM-TD) measured according to ISO 527-3 is in the range of 700 to 1500 MPa; c) the dart drop impact (DDI) measured according to ISO 7765-1 is in the range of 100 to 600 g. The multilayer film (F) has a haze value measured according to ASTM D1003 in the range of 10% to 40%.

16. The multilayer film (F) according to claim 1 or 2, wherein The multilayer film (F) has one or more of the following properties:

17. The multilayer film (F) according to claim 1 or 2, wherein a) the seal initiation temperature (SIT) measured according to the method specified in the measurement method is in the range of 115 to 130 °C; ​ b) a pre-sterilization seal strength (b.s.) of 15 to 40 N / mm, measured according to the method specified in the measurement method; c) a post-sterilization seal strength (a.s.) of 20 to 45 N / mm, measured according to the method specified in the measurement method.

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