Polypropylene composition with excellent sealing properties

Abstract

The present invention provides a polypropylene composition (I), which comprises: (A) at least 90% by weight of a propylene polymer comprising: (a) 20 to 44% by weight of a propylene-hexene copolymer; (b) 25 to 45% by weight of a propylene-hexene-ethylene terpolymer; and (c) 25 to 50% by weight of a propylene-ethylene copolymer, wherein: - the melt flow rate of components (a)+(b)+(c) is in the range of 3.5 to 12.0 g / 10 min; - the xylene solubles content of the propylene polymer (A) is in the range of 16.4% to 35.3% by weight; and - the melting point of the propylene polymer (A) is in the range of 122°C to 132°C; and (B) not more than 10.0% by weight of polybutene, wherein the amounts of (A) and (B) are based on the combined weight of (A)+(B).

Description

[Technical Field]

[0001] This disclosure relates to polypropylene compositions comprising copolymers of propylene and 1-hexene, propylene-ethylene-hexecentrate polymers, and copolymers of propylene and ethylene, which are blended with polybutene and are particularly suitable for the production of films such as biaxially oriented polypropylene (BOPP) and cast films, which have a low seal onset temperature (SIT), a high crystallization temperature, and a low fish-eye number. [Background technology]

[0002] Copolymers of propylene and 1-hexene are already known in the art. For example, WO2006 / 002778 describes a copolymer of propylene and 1-hexene having 0.2% to 5% by weight of 1-hexene-derived units. This copolymer has a unimodal molecular weight distribution and is used in pipe systems.

[0003] WO2017 / 097579 relates to compositions comprising copolymers of propylene and 1-hexene and copolymers of propylene and ethylene, which are particularly suitable for the production of films, especially biaxially oriented polypropylene films (BOPP) and cast films with low seal onset temperature (SIT) and high transparency. The seal onset temperature is not yet sufficient and can be lowered.

[0004] WO2018 / 202396 relates to a propylene polymer composition comprising 35% to 65% by weight of propylene-1-hexene copolymer containing 10.2 to 13% by weight of 1-hexene-derived units, and 35% to 65% by weight of propylene-ethylene copolymer containing 1.5% to 6.5% by weight of ethylene-derived units. The exemplified composition exhibits high xylene soluble content even with low SIT.

[0005] Films containing a blend of polypropylene and polybutene-1 in the outer sealing layer are known in the art.

[0006] Patent application WO2004 / 048424 discloses a multilayer film with a low seal initiation temperature, the seal layer comprising a combination of polybutene-1 containing 2.1 mol% ethylene and a propylene-butene-ethylene terpolymer.

[0007] WO2012 / 031953 discloses the use of butene-1 homo or copolymer to lower the seal initiation temperature of a seal layer containing propylene copolymer and hexene-1. The number of fisheyes was also reduced in the film.

[0008] The applicant has found that by using a polypropylene composition comprising propylene-1-hexene copolymer, propylene-1-hexene-ethylene terpolymer, and propylene-ethylene copolymer as component (A), and polybutene as component (B), it is possible to produce a film or sheet with a low seal initiation temperature (SIT), a high crystallization temperature, good optical properties, and a low number of fisheyes. [Overview of the project]

[0009] This disclosure relates to a polypropylene composition (I), (A) A propylene polymer of at least 90.0% by weight, where (a) + (b) + (c) is 100% by weight, (a) Based on the weight of component (a), 20% to 44% by weight of propylene-hexene copolymer containing 5.0% to 8.3% by weight of hexene-derived units and having a melt flow rate (MFR(a)) of 3.5 to 8.5 g / 10 min as measured according to ISO 1133-1:2011 (230℃ / 2.16kg), (b) It contains 7.2% to 12.0% by weight of hexene-derived units and 0.5% to 2.5% by weight of ethylene-derived units, and the melt flow rate (MFR(a+b)) of components a)+b) measured according to ISO 1133-1:2011 (230 °C / 2.16 kg) is in the range of 3.5 to 8.5 g / 10 min, 25% to 45% by weight of propylene-hexene-ethylene terpolymer, and (c) It contains 3.5% to 8.7% by weight of ethylene-derived units, and The melt flow rate of components (a)+(b)+(c) measured according to ISO -1:2011 (230 °C / 2.16 kg) is in the range of 3.5 to 12.0 g / 10 min, 25% to 50% by weight of propylene-ethylene copolymer, and The propylene polymer (A) is (i) The xylene-soluble content at 25 °C is in the range of 13.0% to 25.0% based on the weight of (a)+(b)+(c), and (ii) It has a melting point in the range of 122 °C to 132 °C, propylene polymer, and (B) polybutene, a polybutene copolymer containing units derived from ethylene and / or propylene of 5.0% by weight or more based on the weight of component (B), and 10.0% by weight or less of polybutene selected from mixtures thereof, and (A) and (B) are based on the total weight of (A)+(B), and the total weight is 100%, to provide a polypropylene composition (I).

[0010] The polypropylene composition (I) of the present disclosure has excellent thermal properties, sealing properties, and optical properties. Therefore, the polypropylene composition (I) is suitable for the production of films or sheets.

[0011] Therefore, a further object of the present disclosure is a film or sheet containing the polypropylene composition (I).

[0012] While several embodiments are disclosed, further embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, the specific embodiments disclosed herein can be modified in various obvious aspects without departing from the spirit and scope of the claims presented herein. Therefore, the following detailed description should be considered as illustrative and not restrictive in nature. [Modes for carrying out the invention]

[0013] In the context of this disclosure, - Percentages are expressed by weight unless otherwise specified. -Unless otherwise specified, the total weight of the polymer composition is 100%. - The term “contains” when referring to polymers, plastic materials, polymer compositions, mixtures, or blends should be interpreted as “contains or essentially constitutes.” - The term "essentially constitutes" means that, in addition to the essential components, other components may be present in the material as long as their presence does not substantially affect the essential properties of the material. Examples of components that, when present in normal amounts, do not substantially affect the properties of the polymer or polyolefin composition, mixture, or blend include catalyst residues, antistatic agents, processing aids, melt stabilizers, light stabilizers, antioxidants, and antacids. - The term "copolymer" refers to a polymer obtained from the intentional polymerization of two different comonomers; in other words, the term "copolymer" does not include terpolymers. - The term "terpolymer" refers to a polymer obtained from the intentional polymerization of three different comonomers. - The term "hexene" refers to hexene-1. The term "butene" refers to butene-1, and the term "polybutene" refers to a polymer of butene-1. - A "film" is a thin layer of material with a thickness of 2000 μm or less. - A "sheet" is a layer of material with a thickness exceeding 2000 μm. - The term "skin layer" refers to the outermost layer of a multilayer film. - The term "base layer" refers to the innermost layer of a multilayer film.

[0014] This disclosure is, -Propylene polymer (A) in an amount of at least 90.0% by weight, preferably 90.0% to 99.5% by weight, more preferably 93.0% to 99.0% by weight, and even more preferably 95.0% to 98.0% by weight, -Polybutene (B) is less than or equal to a certain percentage by weight, preferably 0.5% to 10.0%, more preferably 1.0% to 7.0%, and even more preferably 2.0% to 5.0%, and includes the following: The amounts of (A) and (B) are based on the total weight of (A) + (B), and the total weight is 100%, providing a polypropylene composition (I).

[0015] The individual components of polypropylene composition (I) are defined in more detail below. These individual components may be included in polypropylene composition (I) in any combination.

[0016] Propylene polymer (A) is (based on the weights of (a) + (b) + (c), this weight is 100%). (a) A propylene-hexene copolymer comprising 20% ​​to 44% by weight, preferably 27% to 40% by weight, more preferably 29% to 35% by weight, based on the weight of component (a), and containing 5.0% to 8.3% by weight, preferably 6.3% to 7.8% by weight, more preferably 6.5% to 7.4% by weight, hexene-derived units based on the weight of component (a), wherein the melt flow rate (MFR(a)) measured according to ISO 1133-1:2011 (230℃ / 2.16kg) is in the range of 3.5 to 8.5 g / 10 min, preferably 4.4 to 8.0 g / 10 min, more preferably 5.0 to 7.0 g / 10 min, (b) A propylene-hexene-ethylene terpolymer comprising 25% to 45% by weight, preferably 35% to 40% by weight, more preferably 36% to 39% by weight, comprising 7.2% to 12.0% by weight, preferably 7.5% to 9.5% by weight, more preferably 8.2% to 9.1% by weight of hexene-derived units and 0.5% to 2.5% by weight, preferably 0.7% to 2.2% by weight, more preferably 0.8% to 2.0% by weight of ethylene-derived units, ISO The melt flow rate (MFR(a+b)) of components a) + b), measured according to 1133-1:2011 (230℃ / 2.16kg), is in the range of 3.5 to 8.5 g / 10 min, preferably 4.4 to 8.0 g / 10 min, more preferably 5.0 to 7.0 g / 10 min, and the amounts of hexene and ethylene are based on the weight of (b), with respect to the propylene-hexene-ethylene terpolymer. (c) Based on the weight of (c), it comprises 25% to 50% by weight, preferably 27% to 40% by weight, more preferably 29% to 35% by weight of propylene-ethylene copolymer, which contains 3.5% to 8.7% by weight, preferably 4.5% to 8.4% by weight of ethylene-derived units, The melt flow rate of component (a)+(b)+(c), measured according to ISO 1133-1:2011 (230℃ / 2.16kg), is in the range of 3.5 to 12.0 g / 10 min, preferably 4.4 to 8.0 g / 10 min, and more preferably 5.0 to 8.5 g / 10 min. Furthermore, propylene polymer (A) (i) xylene-soluble content at 25°C, in the range of 13.0% to 25.0% by weight, preferably 14.0% to 23.0% by weight, and more preferably 15.0% to 20.0% by weight, (ii) Having a melting point of 122°C to 132°C, preferably 125°C to 131°C, and more preferably 126°C to 130°C.

[0017] Preferably, the propylene polymer (A) is a reactor blend of components (a), (b), and (c). The method for producing the propylene polymer (A) is preferably carried out in the presence of a highly stereospecific heterogeneous Ziegler-Natta catalyst. A Ziegler-Natta catalyst suitable for producing the propylene-ethylene copolymer of the present disclosure comprises at least one titanium compound having at least one titanium-halogen bond and at least one electron-donating compound (internal donor), both comprising solid catalyst components supported on magnesium chloride. The Ziegler-Natta catalyst system further comprises an organoaluminum compound as an essential co-catalyst and optionally an external electron-donating compound.

[0018] Suitable catalyst systems are described in European patents EP45977, EP361494, EP728769, EP1272533 and international patent application W000163261.

[0019] The organoaluminum compound is preferably an alkyl-Al selected from trialkylaluminum compounds such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum. It is also possible to use a mixture of trialkylaluminum with alkylaluminum halide, alkylaluminum hydride, or alkylaluminum sesquichloride (e.g., AlEt2Cl and Al2Et3Cl3).

[0020] Preferred external electron donor compounds include silicon compounds, ethers, esters such as ethyl 4-ethoxybenzoate, amines, heterocyclic compounds, particularly 2,2,6,6-tetramethylpiperidine, ketones, and 1,3-diethers. Another class of preferred external donor compounds is formula R a 5 R b 6 Si(OR 7 ) cis a silicon compound, where a and b are integers from 0 to 2, c is an integer from 1 to 3, and the sum (a + b + c) is 4, and R 5 , R 6 , and R 7 are alkyl, cycloalkyl, or aryl radicals having 1 to 18 carbon atoms and optionally containing heteroatoms. Particularly preferred are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, 2-ethylpiperidinyl-2-t-butyldimethoxysilane, and 1,1,1-trifluoropropyl-2-ethylpiperidinyl-dimethoxysilane and 1,1,1-trifluoropropyl-methyl-dimethoxysilane. The external electron donor compound is used in an amount such that the molar ratio of the organoaluminum compound to the electron donor compound is from 0.1 to 500, preferably from 1 to 100, more preferably from 2 to 50.

[0021] The polymerization process is continuous or batchwise and is preferably carried out according to known techniques, either in the gas phase or the liquid phase, optionally in the presence of an inert diluent, or by the mixed gas technique.

[0022] Gas phase polymerization is preferably carried out in three reactors, and each component is produced in a different reactor. More preferably, components (a) and (b) are obtained in the first two reactors, respectively, and component (c) is obtained in the third and final reactor.

[0023] The polymerization reaction time, pressure, and temperature are not critical, but a polymerization temperature in the range of 20 °C to 100 °C is desirable. The polymerization pressure is atmospheric pressure or, if possible, higher.

[0024] The molecular weight of components (a), (b), and (c) is adjusted by using known molecular weight regulators, particularly hydrogen.

[0025] Preferably, component (B) is a butene-ethylene copolymer. More preferably, component (B) is a butene-ethylene copolymer having at least one, preferably all, of the following properties.

[0026] -Based on the weight of (B), the content of ethylene-derived units is in the range of 1.0% to 4.5% by weight, preferably 1.5% to 4.5% by weight, more preferably 2.0% to 4.0% by weight, and / or

[0027] - The melting point Tm(I) of form I, measured by DSC according to ISO 11357-3:2018, is less than 100°C, preferably between 80°C and 100°C, more preferably between 90°C and 97°C, and / or

[0028] - The melt flow rate, measured according to ISO 1133-1:2011 (190℃ / 2.16kg), is in the range of 1.0 to 6.0 g / 10 min, preferably 2.0 to 5.0 g / 10 min, more preferably 3.0 to 4.5 g / 10 min, and / or

[0029] - The flexural modulus measured according to ISO 178:2010 is 80 MPa or higher, preferably in the range of 80 to 250 MPa, more preferably in the range of 100 to 210 MPa.

[0030] In preferred embodiments, in addition to one or more of the above characteristics, the butene-ethylene copolymer (B) has a molecular weight distribution Mw / Mn in the range of 4.0 to 9.0, preferably 4.0 to 8.0, more preferably 4.0 to 7.0, and even more preferably greater than 4.5 and less than 6.0.

[0031] In some embodiments, polybutene (B) is obtained using a metallocene-based catalyst system.

[0032] In a preferred embodiment, polybutene (B) is obtained by polymerizing the relevant monomers in the presence of a Ziegler-Natta catalyst system, as described above.

[0033] The polymerization process can be carried out according to known techniques, such as slurry polymerization using a liquid inert hydrocarbon as a diluent, or solution polymerization using, for example, liquid butene as the reaction medium. It is also possible to carry out the polymerization process in the gas phase by operating in one or more fluidized bed reactors or mechanically agitated bed reactors. Solution polymerization carried out using liquid butene as the reaction medium is highly preferred.

[0034] Polymerization is typically carried out at temperatures between 20°C and 120°C, preferably between 40°C and 90°C. Polymerization can be carried out in one or more reactors that can operate under the same or different reaction conditions, such as the concentration of molecular weight modifiers, the concentration of comonomers, temperature, and pressure.

[0035] A suitable catalyst system and polymerization method for obtaining polybutene (B) is disclosed in Patent Document WO2004 / 048424A1.

[0036] Polybutene (B) is commercially available, for example, under the brand name Toppyl sold by LyondellBasell.

[0037] In one embodiment, the polypropylene composition (I) contains 5.0% by weight or less, more preferably 0.01% to 5.0% by weight, of at least one additive (C) selected from the group consisting of nucleating agents, antistatic agents, antioxidants, light stabilizers, lubricants, antacids, melt stabilizers, and combinations thereof, and the amount of the additive is based on the total weight of the polypropylene composition (I) containing the additive, with the total weight being 100%.

[0038] In one embodiment, the polyolefin composition (I) comprises the above-described components (A), component (B), and optionally an additive (C).

[0039] The polyolefin composition (I) is obtained by mixing components (A), (B), and optionally (C) in a conventional melt-mixing apparatus, such as a twin-screw extruder, under conventional conditions.

[0040] Polypropylene composition (I) has excellent thermal and sealing properties, making it advantageous for use in the manufacture of films or sheets. Its relatively high melting point improves the processability of the composition when used in the manufacture of films and sheets. Its low SIT value makes the films and sheets suitable for sealing applications. Polyolefin composition (I) also yields films or sheets with a low fisheye count.

[0041] Advantageously, the ΔTm-SIT (the difference between Tm of the polypropylene composition (I) and the SIT measured for the BOPP film) is broad, which enables good processability of the film.

[0042] Preferably, the SIT measured for the BOPP film is in the range of 70°C to 85°C, more preferably 72°C to 83°C.

[0043] In preferred embodiments, the ΔTm-SIT value measured for the BOPP film is in the range of 40.0°C to 60.0°C, preferably 45.0°C to 55°C, and the Tm of the polypropylene composition (I) and the SIT on the BOPP film are measured as follows.

[0044] In a further embodiment, the present disclosure relates to a film or sheet comprising or comprising a polypropylene composition (I) described in any one of the above embodiments.

[0045] The film or sheet is single-layer or multi-layer, preferably a multi-layer film or sheet in which the polypropylene composition (I) is contained in at least one skin layer, and more preferably a multi-layer film or sheet in which it is contained in both skin layers.

[0046] The features describing the subject matter of this disclosure are not closely related to one another. Therefore, the preferred range of one feature may be combined with the more preferred or less preferred range of another feature, regardless of the level of preference. Examples

[0047] The following examples are provided to illustrate the present invention without limiting it.

[0048] Characterization Methods: The following methods are used to determine the characteristics shown in the specification, claims, and examples.

[0049] Melt flow rate: Measured according to ISO 1133-1:2011 method (230°C / 2.16 kg for propylene polymer, 190°C / 2.16 kg for polybutene).

[0050] Solubility of propylene polymer in xylene at 25°C: Place 2.5 g of polymer sample and 250 ml of xylene in a glass flask equipped with a refrigerator and magnetic stirrer. Raise the temperature to 135°C in 30 minutes. Stir the resulting clear solution under reflux for another 30 minutes. Cool the solution in two stages. In the first stage, lower the temperature to 100°C in air for 10-15 minutes while stirring. In the second stage, transfer the flask to a thermostat-controlled water bath at 25°C for 30 minutes. Lower the temperature to 25°C without stirring for the first 20 minutes, and maintain 25°C with stirring for the last 10 minutes. Filter the formed solid through quick-drying filter paper (e.g., Whatman filter paper grade 4 or 541). Pour 100 ml of the filtered solution (S1) into a pre-weighed aluminum container and heat to 140°C on a heating plate under a nitrogen stream to evaporate and remove the solvent. Next, the container is placed in an 80°C oven under vacuum and left until the weight stabilizes. Then, the amount of polymer that dissolves in xylene at 25°C is calculated. The XS(I) and XSA values ​​are determined experimentally. The proportion of component (B) that dissolves in xylene at 25°C (XSB) can be calculated using the following formula. XS = W(A) × (XS A )+W(B)×(XS B ) Here, W(A) and W(B) are relative quantities of components (A) and (B), respectively, and W(A) + W(B) = 1.

[0051] Hexene content of propylene-hexene copolymers as determined by NMR: 13 The 13C NMR spectrum is acquired using an AV-600 spectrometer operating at 150.91 MHz in Fourier transform mode at 120°C. The propylene CH peak is used as an internal reference at 28.83. 13 The 13C NMR spectrum is obtained using the following parameters.

[0052] [Table 1]

[0053] The total amount of 1-hexene is calculated from the diad as a mole percent using the following relationship: [P] = PP + 0.5PH [H] = HH + 0.5PH

[0054] Propylene / 1-hexene copolymer 13 The assignment of the 13C NMR spectrum is calculated according to the following table.

[0055] [Table 2]

[0056] Ethylene content of propylene-ethylene copolymers as determined by NMR: 13 The 13C NMR spectrum is acquired using a Bruker AV-600 spectrometer with a cryoprobe, operating at 160.91 MHz in Fourier transform mode at 120°C. The peak of the Sββ carbon (" 13 C Monomer sequence distribution of ethylene propylene rubber measured by NMR. 3. Use of reaction stochastic mode (nomenclature according to CJ Carman, RA Harrington and CE Wilkes, Macromolecules, 1977, 10, 536) is used as an internal reference at 29.9 ppm. The sample is dissolved in 1,1,2,2-tetrachloroethane-d2 at 120°C at a concentration of 8% wt / v. Each spectrum is acquired using a 90° pulse, a 15-second delay between pulses, and CPD to remove 1H-13C coupling. 512 transients are stored at 32K data points using a 9000 Hz spectral window. Spectral assignment, evaluation of triad distribution, and composition are performed according to Kakugo ("Carbon-13 NMR measurement of monomer sequence distribution in ethylene-propylene copolymer prepared with δ-titanium trichloride-diethylaluminum chloride," M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 1982, 15, 1150) using the following formula. PPP=100Tββ / S PPE=100Tβδ / S EPE=100Tδδ / S PEP=100Sββ / S PEE=100Sβδ / S EEE=100(0.25 Sγδ+0.5 Sδδ) / S S=Tββ+Tβδ+Tδδ+Sββ+Sβδ+0.25 Sγδ+0.5 Sδδ

[0057] The molar percentage of ethylene content is evaluated using the following formula: E%mol = 100 * [PEP + PEE + EEE]

[0058] The weight percentage of ethylene content is evaluated using the following formula:

[0059]

number

[0060] Here, P%mol is the molar percentage of propylene content, and MW E and MW P These are the molecular weights of ethylene and propylene, respectively.

[0061] The product of the reactivity ratios r1 and r2 is calculated according to Carman (CJ Carman, RA Harrington and CE Wilkes, Macromolecules, 1977; 10, 536) as follows:

number

[0062] The stereoregularity of the propylene sequence is PPP mmT ββ (28.90~29.65 ppm) and the overall T ββ The content in millimeters is calculated from the ratio (29.80 to 28.37 ppm).

[0063] Hexene and ethylene content of propylene-hexene-ethylene terpolymer: 13 The 13C NMR spectrum is acquired using an AV-600 spectrometer operating at 120°C, Fourier transform mode, and 150.91 MHz. The propylene CH peak is used as an internal reference at 28.83. 13 The 13C NMR spectrum is obtained using the following parameters: Spectral width (SW): 60 ppm Spectral center (O1): 30 ppm Decoupling sequence: WALTZ 65_64pl Pulse program (1): ZGPG Pulse length (P1)(2): 90° Total score (TD): 32K Relaxation delay (2): 15 seconds Number of transients (3): 1500

[0064] The total amount of 1-hexene and ethylene is calculated from the dyad as mole percent using the following relationship: [P] = PP + 0.5PH + 0.5PE [H] = HH + 0.5PH [E]=EE+0.5PE

[0065] Propylene / 1-hexene / ethylene copolymer 13 The assignment of the 13C NMR spectrum is calculated according to the following table.

[0066] [Table 3]

[0067] Polybutene comonomer content: 13 ¹³C NMR spectra are acquired using a Bruker AV-600 spectrometer with a cryoprobe, operating in Fourier transform mode at 120°C. Samples are dissolved in 1,1,2,2-tetrachloroethane-d2 at an 8% wt / v concentration at 120°C. Each spectrum is acquired with a 90° pulse, with a 15-second delay between the pulse and the CPD to remove 1H-13C coupling. The spectrometer operates at 160.91 MHz. The Sδδ carbon peak (" 13 Monomer sequence distribution of ethylene propylene rubber by 13C NMR. 3. Use of reaction stochastic mode (nomenclature according to CJ Carman, RA Harrington and CE Wilkes, Macromolecules, 1977, 10, 536) is used as an internal reference at 29.9 ppm, and 512 transients are stored at 32K data points using a 9000 Hz spectral window.

[0068] The spectral assignment, evaluation of the triad distribution, and composition are determined using the following formula, according to Kakugo [M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 16, 4, 1160 (1982)] and Randall [JC Randall, Macromol. Chem Phys., C30, 211 (1989)]. BBB=100T ββ / S BBE=100T βδ / S EBE=100P δδ / S BEB=100S ββ / S BEE=100S αδ / S EEE=100(0.25 S γδ +0.5 S δδ ) / S S=T ββ +T βδ +P δδ +S ββ +S αδ +0.25 S γδ +0.5 S δδ

[0069] The total amount (mol percent) of 1-butene and ethylene is calculated from the triad using the following relationship: [E] = EEE + BEE + BEB [B] = BBB + BBE + EBE

[0070] The weight percentage (E%wt) of ethylene content is calculated using the following formula:

[0071]

number

[0072] Molecular weight distribution Mw / Mn: The average Mn and Mw, and the resulting Mw / Mn, are measured using a Waters GPCV 2000 instrument equipped with a column set of four PLgel Olexis mixed gels (Polymer Laboratories) and an IR4 infrared detector (Polymer Char). The column dimensions are 300 (7.5 mm), and the particle size is 13 μm. 1,2,4-trichlorobenzene (TCB) is used as the mobile phase, maintained at a flow rate of 1.0 ml / min, and all measurements are performed at 150°C. The solution concentration is 0.1 g / dl in TCB, with 0.1 g / l of 2,6-diterbutyl-p-cresol added to prevent degradation. For GPC calculations, a universal calibration curve is obtained using 10 polystyrene (PS) standard samples (peak molecular weight range 580-8500000) provided by Polymer Laboratories. The experimental data are interpolated, and a cubic polynomial approximation is used to obtain the relevant calibration curve. Data acquisition and processing are performed using Empower (Waters). The Mark-Howink relation is used to determine the molecular weight distribution and the associated average molecular weight. The K value is KPS = 1.21 (10) for PS and PB, respectively. -4 dL / g and KPB = 1.78 (10 -4 The values ​​are in dL / g, and the Mark-Howink index used is α=0.706 for PS and α=0.725 for PB. For butene-1 / ethylene copolymers, for data evaluation, it is assumed that the composition is constant across the entire molecular weight range, and the K value of the Mark-Howink relationship is calculated using a linear combination as shown below.

[0073]

number

[0074] Melting point: Measured according to the method of ISO 11357-3:2018. Polypropylene and polypropylene compositions Under a nitrogen stream, with a sample weight of 5-7 mg, the scanning rate during cooling and heating is 20°C / min. The instrument is calibrated using indium. Polybutene To measure the melting point (Tm(I)) of polybutene crystalline form I, the sample is melted, held at 200°C for 5 minutes, then cooled to 20°C at a cooling rate of 10°C / min, and the sample is then stored at room temperature for 10 days. After 10 days, the sample is subjected to DSC, cooled to -20°C, and then heated to 200°C at a scanning rate of 10°C / min. In this heating experiment, the first peak temperature from the low-temperature side of the thermogram is adopted as the melting point Tm(I).

[0075] The flexural modulus is measured in the case of propylene polymers according to method ISO 178:2010 using injection-molded specimens (80 × 10 × 4 mm) (obtained according to ISO 1873-2:2007), and in the case of butene polymers using compression-molded specimens. Butene copolymer specimens are prepared at 23°C for 10 days before testing.

[0076] Preparation of BOPP film test specimens: Each test composition was extruded using a single-screw choline extruder (screw length / diameter ratio 1:25) at a film extraction speed of 7 m / min and a melting temperature of 210-250°C to produce a 50 μm thick film. Each film was then superimposed onto a 1000 μm thick propylene homopolymer film with a xylene insoluble content of 97% by weight and an MFR (ISO1133-1:2011, 230°C / 2.16 kg) of 2.0 g / 10 min. The superimposed films were then measured at 35 kg × cm². 2The laminates are bonded together by flat plate pressing at 200°C under load, and maintained in this state for 5 minutes. The resulting laminate is then stretched seven times simultaneously in both the longitudinal and transverse directions (i.e., biaxial directions) at 160°C using a Karo 4 Brueckener film stretcher to obtain a 20 μm thick BOPP film (18 μm homopolymer + 2 μm test composition).

[0077] BOPP film sealing start temperature: A 6cm wide, 35cm long film strip is cut from the center of a BOPP film and overlapped with a BOPP film made of PP homopolymer. The overlapped test piece is sealed along one of the 2cm sides using a Brugger Feinmechanik Sealer, model HSG-ETK745. The sealing time is 5 seconds at a pressure of 0.14 MPa (20 psi). The sealing start temperature is approximately 10°C lower than the melting point of the test composition. The sealed strip is cut into six 15mm wide test pieces that fit into the grips of a tensile testing machine. The seal strength is tested with a load cell capacity of 100N, a cross speed of 100mm / min, and a grip distance of 50mm. The results are expressed as the average of the maximum seal strength (N). Then, after cooling, the unsealed end is attached to an Instron machine and tested at a tensile speed of 50mm / min.

[0078] Next, repeat the test by changing the temperature as follows.

[0079] If the seal strength is less than 1.5N, increase the temperature.

[0080] If the seal strength exceeds 1.5N, reduce the temperature.

[0081] The temperature change needs to be adjusted in steps; if the seal strength is close to the target, select a 1°C step, and if it is far from the target, select a 2°C step.

[0082] The target seal strength (SIT) is defined as the lowest temperature at which a seal strength of 1.5 N or higher is achieved.

[0083] raw materials

[0084] Irganox 1010 Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), sold by BASF.

[0085] Irgafos168 Tris(2,4-di-tert-butylphenyl) phosphite, marketed by BASF.

[0086] PB1(B) : A copolymer of butene-1 and ethylene, with an ethylene content of 3.5 wt%, Tm(I) of 94°C, molecular weight distribution Mw / Mn of 5.6, melt flow rate of 3.1 g / 10 min (ISO 1133-1:2011, 190°C / 2.16 kg), and flexural modulus (ISO 178:2010) of 120 MPa. The butene-1 copolymer was obtained by sequential polymerization in two reactors using butene-1 as a liquid medium and a Ziegler-Natta catalyst system according to Example 11 of Patent WO2004 / 048424. The polymerization conditions in the first reactor were a temperature of 75°C and a hydrogen / butene supply ratio of 1000 ppmV. After 2.5 hours, the polymerization contents of the first reactor were transferred to the second reactor, and copolymerization was continued under the same conditions except that the supply of ethylene was stopped. Polymerization was stopped after 2 hours.

[0087] PB2(B) : A copolymer of butene-1 and ethylene, with an ethylene content of 3.5% by weight, a Tm(I) of 65°C, a molecular weight distribution Mw / Mn of 2.2, a melt flow rate of 3.3 g / 10 min (ISO 1133-1:2011, 190°C / 2.16 kg), and a flexural modulus of 130 MPa (ISO 178:2010).

[0088] Propylene polymer (A)

[0089] Procedure for producing spherical adducts: Except for adding powdered BiCl3 in an amount of 3 mol% relative to magnesium before supplying the oil, the microspherical MgCl2·pC2H5OH adducts are produced according to the method described in Comparative Example 5 of WO98 / 44009.

[0090] Preparation procedure for the solid catalyst component: Except as noted below, the solid catalyst component is prepared according to Example 1 of EP728769.

[0091] - The second and third titaniumization processes are carried out at 110°C (not 120°C).

[0092] - MgCl in the form of spherical solid particles with a maximum diameter of 65 microns or less (not 50 microns) 2.3 C2H5OH is used.

[0093] Catalyst system and prepolymerization treatment: Before introducing the solid catalyst components into the polymerization reactor, they are brought into contact with aluminum triethyl (TEAL) and dicyclopentyl dimethoxysilane (DCPMS) as external donors at 15°C for approximately 6 minutes.

[0094] Next, the catalyst system is suspended in liquid propylene at 20°C for approximately 20 minutes to carry out prepolymerization, after which it is introduced into the polymerization reactor.

[0095] Polymerization: A propylene-hexene copolymer (component (a)) is produced by continuously supplying a prepolymerization catalyst system, hydrogen, propylene, and 1-hexene in gaseous form at a constant flow rate to the first gas-phase polymerization reactor. The propylene copolymer produced in the first reactor is discharged as a continuous flow and introduced as a continuous flow to the second gas-phase polymerization reactor along with a quantitatively constant flow of gaseous hydrogen, hexene, ethylene, and propylene. The propylene copolymer produced in the second reactor is discharged as a continuous flow, and after the removal of unreacted monomers, it is introduced as a continuous flow to the third gas-phase polymerization reactor along with a quantitatively constant flow of gaseous hydrogen, hexene, and propylene. The polymerization conditions are shown in Table 1.

[0096] Table 1 [Table 4]

[0097] The polymer obtained from polymerization experiments was pelletized by adding 0.05% by weight of Irganox1010, 0.1% by weight of Irgafos168, and 0.05% of calcium stearate. Here, the amount of additives is based on the total weight of the polymer including the additives. Table 2 shows the characteristics of the propylene polymer.

[0098] Table 2 [Table 5]

[0099] Examples E1-E3

[0100] Propylene polymer (A) and polybutene (B) are melt-mixed in the proportions shown in Table 3 using a twin-screw extruder (Werner 58, model WPZSK-58) at a rotational speed of 220 rpm and an extruder output of 220 kg / h.

[0101] Table 3 shows the thermal and sealing properties of the polypropylene composition. The polypropylene composition was shown to have a significantly lower number of fisheyes on the cast film.

[0102] Table 3 [Table 6]

Claims

1. Polypropylene composition (I), (A) at least 90.0% by weight of a propylene polymer, (based on the weights of (a) + (b) + (c)) (a) 20% to 44% by weight of propylene-hexene copolymer, which contains 5.0% to 8.3% by weight of hexene-derived units based on the weight of component (a), and has a melt flow rate (MFR(a)) in the range of 3.5 to 8.5 g / 10 min as measured according to ISO 1133-1:2011 (230°C / 2.16 kg), (b) 25% to 45% by weight of propylene-hexene-ethylene terpolymer, comprising 7.2% to 12.0% by weight of hexene-derived units and 0.5% to 2.5% by weight of ethylene-derived units, with a melt flow rate (MFR(a+b)) of components a) + b) measured according to ISO 1133-1:2011 (230°C / 2.16 kg) in the range of 3.5 to 8.5 g / 10 min, (c) Contains 3.5% to 8.7% by weight of ethylene-derived units, The material comprises 25% to 50% by weight of a propylene-ethylene copolymer, wherein the melt flow rate of component (a) + (b) + (c), measured according to ISO 1133-1:2011 (230°C / 2.16 kg), is in the range of 3.5 to 12.0 g / 10 min. The propylene polymer (A) is (i) Xylene soluble content at 25°C, in the range of 13.0% to 25.0% by weight based on the weight of (a) + (b) + (c), and (ii) The propylene polymer having a melting point in the range of 122°C to 132°C, (B) a butene homopolymer, a butene copolymer containing 5.0% by weight or more of ethylene and / or propylene-derived units based on the weight of component (B), and a mixture thereof, comprising 10.0% by weight or less of polybutene, The amounts of (A) and (B) are based on the total weight of (A) + (B) of the polypropylene composition (I).

2. -90.0% to 99.5% by weight of the propylene polymer (A), - Contains 0.5% to 10.0% by weight of polybutene (B), The amounts of (A) and (B) are based on the total weight of (A) + (B) as described in claim 1, the polypropylene composition (I).

3. The propylene polymer (A) is determined based on the weight of (a) + (b) + (c), (a) 27% to 40% by weight of the propylene-hexene copolymer, (b) 35% to 40% by weight of the propylene-hexene-ethylene terpolymer, (c) The polypropylene composition (I) according to claim 1 or 2, comprising 27% to 40% by weight of the propylene-ethylene copolymer.

4. The polypropylene composition (I) according to claim 1, wherein component (B) is a butene-ethylene copolymer having at least one of the following properties: - The content of the ethylene-derived units is in the range of 1.0% by weight to 4.5% by weight, based on the weight of (B), and / or - The melting point Tm(I) of form I, measured by DSC according to ISO 11357-3:2018, is less than 100°C, and / or - The melt flow rate, measured according to ISO 1133-1:2011 (190°C / 2.16 kg), is in the range of 1.0 to 6.0 g / 10 min, and / or - The flexural modulus, as measured according to ISO 178:2010, must be 80 MPa or higher.

5. The polypropylene composition (I) according to claim 1, having at least one of the following properties: - The measured seal start temperature (SIT) for the BOPP film is in the range of 70°C to 85°C, and / or The -ΔTm-SIT value is in the range of 40.0°C to 60.0°C, where Tm is the melting point of the polypropylene composition (I), and SIT is the seal start temperature measured for the BOPP film.

6. A film or sheet comprising the polypropylene composition (I) described in claim 1.

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