Polypropylene composition with good sealing performance

Abstract

A polypropylene composition (I) comprising: (A) at least 90 wt.% of a propylene polymer comprising: (a) from 20 wt.% to 44 wt.% of a propylene-hexene copolymer, (b) from 25 wt.% to 45 wt.% of a propylene-hexene-ethylene terpolymer, (c) from 25 wt.% to 50 wt.% of a propylene-ethylene copolymer; wherein-the melt flow rate of components (a) + (b) + (c) ranges from 3.5 to 12.0 g / 10 min; the propylene polymer (A) has a xylene soluble content ranging from 16.4% to 35.3% by weight, and the propylene polymer (A) has a melting point ranging from 122 DEG C to 132 DEG C, and (B) up to and including 10.0% by weight of polybutene, the amounts of (A) and (B) being based on the total weight of (A) + (B).

Description

Technical Field

[0001] The present disclosure relates to a polypropylene composition comprising a copolymer of propylene and 1-hexene, a propylene-ethylene-hexene terpolymer and a copolymer of propylene and ethylene, which is blended with polybutene and is particularly suitable for preparing films with low seal initiation temperature (SIT), high crystallization temperature and reduced fisheye number, especially biaxially oriented polypropylene film (BOPP) and cast film. Background Art

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

[0003] WO2017 / 097579 relates to a composition comprising a copolymer of propylene and 1-hexene and a copolymer of propylene and ethylene, which is particularly suitable for preparing films with low seal initiation temperature (SIT) and high transparency, in particular biaxially oriented polypropylene films (BOPP) and cast films. The seal initiation temperature is still unsatisfactory and can be reduced.

[0004] WO2018 / 202396 relates to a propylene polymer composition comprising: 35 wt.% to 65 wt.% of a propylene 1-hexene copolymer containing 10.2 wt.% to 13 wt.% of 1-hexene derived units and 35 wt.% to 65 wt.% of a propylene ethylene copolymer containing 1.5 wt.% to 6.5 wt.% of ethylene derived units. Even though the exemplified compositions show low SIT, the xylene solubles content is high.

[0005] Films containing blends of polypropylene and polybutene-1 in the outer sealant layer are known in the art.

[0006] Patent application WO 2004 / 048424 discloses a multilayer film having a low sealing initiation temperature, wherein the sealing layer comprises a combination of polybutene-1 containing 2.1 mol % of ethylene and a propylene-butene-ethylene terpolymer.

[0007] In WO 2012 / 031953 it is disclosed to use butene-1 homopolymer or copolymer to reduce the seal initiation temperature of a seal layer containing a propylene copolymer with hexene- 1. The film also has a reduced number of fisheyes.

[0008] The applicant has found that by using a polypropylene composition comprising a propylene 1-hexene copolymer, a propylene 1-hexene ethylene terpolymer and a propylene ethylene copolymer as component (A) and polybutene as component (B), a film or sheet having a low seal initiation temperature (SIT), a high crystallization temperature, good optical properties and a low fisheye number can be produced. Summary of the invention

[0009] The present disclosure provides a polypropylene composition (I), comprising:

[0010] (A) at least 90.0 wt% of a propylene polymer comprising (based on the weight of (a) + (b) + (c), 100 wt%):

[0011] (a) 20 to 44 wt% of a propylene-hexene copolymer comprising 5.0 to 8.3 wt% of hexene-derived units, based on the weight of component (a), and having a melt flow rate (MFR(a)) in the range of 3.5 to 8.5 g / 10 min measured according to ISO 1133-1:2011 (230°C / 2.16 kg);

[0012] (b) 25 to 45 wt% of a propylene-hexene-ethylene terpolymer comprising 7.2 to 12.0 wt% of hexene-derived units and 0.5 to 2.5 wt% of ethylene-derived units, wherein the melt flow rate (MFR(a+b)) of component 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; and

[0013] (c) 25 to 50 wt.% of a propylene-ethylene copolymer comprising 3.5 to 8.7 wt.% of ethylene-derived units,

[0014] wherein the melt flow rate of components (a)+(b)+(c) measured according to ISO 1133-1:2011 (230°C / 2.16kg) ranges from 3.5 to 12.0 g / 10 min, and

[0015] Wherein the propylene polymer (A) has:

[0016] (i) a xylene solubles content in the range of 13.0 wt. % to 25.0 wt. % based on the weight of (a) + (b) + (c) at 25°C; and

[0017] (ii) a melting point ranging from 122°C to 132°C; and

[0018] (B) up to and including 10.0 wt. % of a polybutene selected from butene homopolymers, butene copolymers having up to and including 5.0 wt. % of units derived from ethylene and / or propylene, based on the weight of component (B), and mixtures thereof,

[0019] The amounts of (A) and (B) are based on the total weight of (A) + (B), and the total weight is 100%.

[0020] The polypropylene composition (I) disclosed in the present invention has good thermal properties, sealing properties and optical properties. Therefore, the polypropylene composition (I) is suitable for producing films or sheets.

[0021] Therefore, another object of the present disclosure is a film or a sheet comprising the polypropylene composition (I).

[0022] Although a number of embodiments are disclosed, other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments as disclosed herein are capable of modification in various obvious aspects without departing from the spirit and scope of the claims presented herein. Therefore, the following detailed description is to be construed as illustrative in nature and not restrictive. DETAILED DESCRIPTION

[0023] In the context of this disclosure;

[0024] - Percentages are expressed by weight unless otherwise stated;

[0025] - the total weight of the polymer composition adds up to 100%, unless otherwise stated;

[0026] - the term "comprising" in relation to a polymer, plastic material, polymer composition, mixture or blend shall be interpreted as meaning "comprising or consisting essentially of";

[0027] - The term "consisting essentially of" means that in addition to the mandatory ones, other components may also be present in the material, provided that the basic characteristics of the material are not substantially affected by their presence. Examples of components that do not substantially affect the characteristics of the polymer or polyolefin composition, mixture or blend when present in conventional amounts are catalyst residues, antistatic agents, processing aids, melt stabilizers, light stabilizers, antioxidants and antacids;

[0028] - the term "copolymer" refers to a polymer derived from the intentional polymerization of two different comonomers, i.e. the term "copolymer" does not include terpolymers;

[0029] - the term "terpolymer" means a polymer derived from the intentional polymerization of three different comonomers;

[0030] - the term "hexene" refers to hexene-1. The term "butene" refers to butene-1, and the term "polybutene" refers to polymers of butene-1;

[0031] - "film" is a thin layer of material having a thickness equal to or less than 2000 μm;

[0032] - A "sheet" is a layer of material greater than 2000 μm thick;

[0033] - The term "skin layer" refers to the outermost layer of a multilayer film;

[0034] - The term "base layer" refers to the innermost layer of a multilayer film.

[0035] The present disclosure provides a polypropylene composition (I), comprising:

[0036] - at least 90.0 wt.-%, preferably 90.0 to 99.5 wt.-%, more preferably 93.0 to 99.0 wt.-%, still more preferably 95.0 to 98.0 wt.-% of propylene polymer (A), and

[0037] - up to and including 10.0 wt.-%, preferably 0.5 to 10.0 wt.-%, more preferably 1.0 to 7.0 wt.-%, still more preferably 2.0 to 5.0 wt.-% of polybutene (B),

[0038] The amounts of (A) and (B) are based on the total weight of (A) + (B), and the total is 100%.

[0039] In the following the individual components of the polypropylene composition (I) are defined in more detail.The individual components may be included in the polypropylene composition (I) in any combination.

[0040] The propylene polymer (A) comprises (based on the weight of (a) + (b) + (c), 100% by weight):

[0041] (a) 20 to 44 wt%, preferably 27 to 40 wt%, more preferably 29 to 35 wt%, based on the weight of component (a), of a propylene-hexene copolymer comprising 5.0 to 8.3 wt%, preferably 6.3 to 7.8 wt%, more preferably 6.5 to 7.4 wt%, based on the weight of component (a), of hexene-derived units and having a melt flow rate (MFR(a)) 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, measured according to ISO 1133-1:2011 (230°C / 2.16 kg);

[0042] (b) 25 to 45 wt%, preferably 35 to 40 wt%, more preferably 36 to 39 wt%, of a propylene-hexene-ethylene terpolymer comprising 7.2 to 12.0 wt%, preferably 7.5 to 9.5 wt%, more preferably 8.2 to 9.1 wt%, of hexene-derived units and 0.5 to 2.5 wt%, preferably 0.7 to 2.2 wt%, more preferably 0.8 to 2.0 wt% of ethylene-derived units, wherein the melt flow rate (MFR(a+b)) of component a) + b) measured according to ISO 1133-1:2011 (230°C / 2.16 kg) ranges from 3.5 to 8.5 g / 10 min, preferably from 4.4 to 8.0 g / 10 min, more preferably from 5.0 to 7.0 g / 10 min, and the amounts of hexene and ethylene are based on the weight of (b);

[0043] (c) 25 to 50 wt%, preferably 27 to 40 wt%, more preferably 29 to 35 wt% of a propylene-ethylene copolymer comprising 3.5 to 8.7 wt%, preferably 4.5 to 8.4 wt%, based on the weight of (c), of ethylene-derived units,

[0044] wherein the melt flow rate of components (a) + (b) + (c) measured according to ISO 1133-1:2011 (230°C / 2.16kg) is in the range of 3.5 to 12.0 g / 10 min, preferably in the range of 4.4 to 8.0 g / 10 min, more preferably in the range of 5.0 to 8.5 g / 10 min,

[0045] and wherein the propylene polymer (A) has:

[0046] (i) a xylene solubles content at 25°C ranging from 13.0 wt% to 25.0 wt%, preferably from 14.0 wt% to 23.0 wt%, more preferably from 15.0 wt% to 20.0 wt%; and

[0047] (ii) a melting point ranging from 122°C to 132°C, preferably from 125°C to 131°C, more preferably from 126°C to 130°C.

[0048] Preferably, the propylene polymer (A) is a reactor blend of components (a), (b) and (c). The method for preparing the propylene polymer (A) is preferably carried out in the presence of a highly stereospecific heterogeneous Ziegler-Natta catalyst. The Ziegler-Natta catalyst suitable for preparing the propylene ethylene copolymer of the present disclosure comprises a solid catalyst component, the solid catalyst component comprising at least one titanium compound having at least one titanium-halogen bond and at least one electron donor compound (internal donor), both of which are supported on magnesium chloride. The Ziegler-Natta catalyst system also includes an organoaluminum compound as a necessary co-catalyst and an optional external electron donor compound.

[0049] Suitable catalyst systems are described in European Patents EP45977, EP361494, EP728769, EP 1272533 and International Patent Application WO00163261.

[0050] The organoaluminum compound is preferably an alkyl-Al selected from trialkylaluminum compounds, such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. A mixture of trialkylaluminum and alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides (such as AlEt2Cl and Al2Et3Cl3) can also be used.

[0051] Preferred external electron donor compounds include silicon compounds, ethers, esters such as ethyl 4-ethoxybenzoate, amines, heterocyclic compounds, and in particular 2,2,6,6-tetramethylpiperidine, ketones and 1,3-diethers. Another preferred class of external donor compounds is the formula R a 5 R b 6 Si(OR 7 ) c A silicon compound wherein a and b are integers from 0 to 2, c is an integer from 1 to 3 and the sum of (a+b+c) is 4; R 5 , R 6 and R 7 is an alkyl, cycloalkyl or aryl group having 1 to 18 carbon atoms, optionally containing heteroatoms. Particularly preferred are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, methyltert-butyldimethoxysilane, dicyclopentyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane and 1,1,1-trifluoropropyl-2-ethylpiperidinyl-dimethoxysilane and 1,1,1-trifluoropropyl-methyl-dimethoxysilane. The amount of the external electron donor compound is such that the molar ratio between the organoaluminum compound and the electron donor compound is from 0.1 to 500; preferably from 1 to 100; more preferably from 2 to 50.

[0052] The polymerization process can be continuous or batchwise and is preferably carried out according to known techniques operating in the gas phase or in the liquid phase, optionally in the presence of an inert diluent, or by mixed liquid-gas techniques.

[0053] Preferably the polymerization is carried out in gas phase in three reactors, wherein each component is prepared 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 last reactor.

[0054] The polymerization time, pressure and temperature are not critical, however, it is preferred if the polymerization temperature ranges from 20° C. to 100° C. The polymerization pressure is atmospheric pressure or preferably higher.

[0055] The molecular weight of components (a), (b) and (c) is regulated by using known molecular weight regulators, in particular hydrogen.

[0056] 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:

[0057] - a content of units derived from ethylene in the range of 1.0 to 4.5 wt.-%, preferably 1.5 to 4.5 wt.-%, more preferably 2.0 to 4.0 wt.-%, still more preferably 2.5 to 3.5 wt.-%, based on the weight of (B); and / or

[0058] - the melting temperature Tm(I) of form I measured by DSC according to method ISO 11357-3:2018 is below 100°C, preferably in the range of 80°C to below 100°C, more preferably from 90°C to 97°C; and / or

[0059] - a melt flow rate in the range of 1.0 to 6.0 g / 10 min, preferably 2.0 to 5.0 g / 10 min, still more preferably 3.0 to 4.5 g / 10 min, measured according to ISO 1133-1:2011 (190°C / 2.16 kg); and / or

[0060] The flexural modulus measured according to ISO 178:2010 is equal to or higher than 80 MPa, preferably in the range of 80 to 250 MPa, more preferably 100 to 210 MPa.

[0061] In a preferred embodiment, in addition to one or more of the above properties, the molecular weight distribution Mw / Mn of the butene-ethylene copolymer (B) ranges from 4.0 to 9.0, preferably from 4.0 to 8.0, more preferably from 4.0 to 7.0, and even more preferably greater than 4.5 to less than 6.0.

[0062] In some embodiments, the polybutene (B) is obtained using a metallocene-based catalyst system.

[0063] In a preferred embodiment, the polybutene (B) is obtained by polymerizing the relevant monomers in the presence of a Ziegler-Natta catalyst system as described above.

[0064] The polymerization process can be carried out according to known techniques, for example slurry polymerization using a liquid inert hydrocarbon as diluent, or solution polymerization using, for example, liquid butene as reaction medium. The polymerization process can also be carried out in the gas phase, operating in one or more fluidized bed or mechanically stirred bed reactors. Solution polymerization using liquid butene as reaction medium is highly preferred.

[0065] The polymerization is generally carried out at a temperature of 20° C. to 120° C., preferably 40° C. to 90° C. The polymerization can be carried out in one or more reactors, which can operate under the same or different reaction conditions such as concentration of molecular weight regulator, comonomer concentration, temperature, pressure, etc.

[0066] Suitable catalyst systems and polymerization processes for obtaining polybutene (B) are disclosed in patent document WO 2004 / 048424 A1.

[0067] Polybutene (B) is also commercially available, for example sold under the trade name Toppyl by LyondellBasell.

[0068] In one embodiment, the polypropylene composition (I) comprises up to and including 5.0 wt.%, more preferably 0.01 wt.% to 5.0 wt.% of at least one additive (C) selected from the group consisting of nucleating agents, antistatic agents, antioxidants, light stabilizers, slip agents, antacids, melt stabilizers and combinations thereof, the amount of the additive being based on the total weight of the polypropylene composition (I) including the additive, the total weight being 100%.

[0069] In one embodiment, the polyolefin composition (I) consists of component (A), component (B) and optional additives (C) as described above.

[0070] The polyolefin composition (I) is obtained by mixing components (A), (B) and optionally (C) in a conventional melt mixing apparatus (eg a twin screw extruder) operating under conventional conditions.

[0071] The polypropylene composition (I) is endowed with good thermal properties and sealing properties so that the composition can be advantageously used to produce films or sheets. When used to produce films or sheets, relatively high melting points cause improved processing properties of the composition. Low SIT values ​​make films or sheets suitable for sealing applications. The polyolefin composition (I) also produces films or sheets with low fisheye counts.

[0072] Advantageously, the ΔTm-SIT (the difference between the Tm of the polypropylene composition (I) and the SIT measured on the BOPP film) is wide allowing for good processability of the film.

[0073] Preferably, the SIT measured on a BOPP film ranges from 70°C to 85°C, more preferably from 72°C to 83°C.

[0074] In a preferred embodiment the ΔTm-SIT value measured on a BOPP film ranges from 40.0 to 60.0°C, preferably from 45.0 to 55°C, wherein the Tm of the polypropylene composition (I) and the SIT on the BOPP film are measured as shown below.

[0075] In another aspect, the present disclosure relates to a film or sheet comprising or consisting of the polypropylene composition (I) as described in any one of the above embodiments.

[0076] The film or sheet is mono-layer or multi-layer, preferably a multi-layer film or sheet, wherein the polypropylene composition (I) is comprised in at least one skin layer, more preferably in both skin layers.

[0077] The features describing the subject matter of the present disclosure are not inseparably linked to each other. Thus, a preferred range for one feature can be combined with a more or less preferred range for a different feature, regardless of their level of preference.

[0078] Examples

[0079] The following examples are given to illustrate the present invention and not for limiting purposes.

[0080] Characterization Methods: The following methods were used to determine the properties indicated in the specification, claims, and examples.

[0081] Melt flow rate: Determined according to method ISO 1133-1:2011 (230°C / 2.16 kg for propylene polymers and 190°C / 2.16 kg for polybutene).

[0082] For the solubility of propylene polymer in xylene at 25°C: 2.5g polymer sample and 250ml xylene are introduced into a glass flask equipped with a refrigerator and a magnetic stirrer. The temperature is raised to 135°C in 30 minutes. The resulting clear solution is kept under reflux and stirred for another 30 minutes. The solution is cooled in two stages. In the first stage, the temperature is reduced to 100°C in air under stirring for 10 to 15 minutes. In the second stage, the flask is transferred to a thermostatically controlled water bath at 25°C for 30 minutes. The temperature is reduced to 25°C without stirring during the first 20 minutes, and maintained at 25°C in the latter 10 minutes under stirring. The solid formed is filtered on a fast filter paper (e.g., Whatman filter paper grade 4 or 541). 100ml of the filtered solution (S1) is poured into a pre-weighed aluminum container, which is heated to 140°C on a heating plate under a nitrogen stream to remove the solvent by evaporation. The container is then kept in an oven at 80°C under vacuum until constant weight is reached. The amount of polymer soluble in xylene at 25°C is then calculated. The XS(I) and XSA values ​​are determined experimentally. The fraction (XSB) of component (B) soluble in xylene at 25°C can be calculated by the following formula:

[0083] XS=W(A)×(XS A )+W(B)×(XS B )

[0084] Wherein W(A) and W(B) are the relative amounts of components (A) and (B), respectively, and W(A)+W(B)=1.

[0085] Hexene content of propylene-hexene copolymers by NMR: 13 C NMR spectra were obtained on an AV-600 spectrometer operating at 150.91 MHz in Fourier transform mode at 120° C. The peak of propylene CH was used as an internal reference at 28.83. 13 C NMR spectra were acquired using the following parameters:

[0086]

[0087]

[0088] The total amount of 1-hexene as a mole percent was calculated from the dyads using the following relationship:

[0089] [P] = PP + 0.5PH

[0090] [H]=HH+0.5PH

[0091] Propylene / 1-hexene copolymer 13 The assignments of C NMR spectra were calculated according to the following table:

[0092] area Chemical shift distribute sequence 1 46.93–46.00 <![CDATA[S αα ]]> PP 2 44.50–43.82 <![CDATA[S αα ]]> PH 3 41.34-4.23 <![CDATA[S αα ]]> HH 4 38.00-37.40 <![CDATA[S αγ +S αδ ]]> PE 5 35.70-35.0 <![CDATA[4B4]]> H 6 35.00-34.53 <![CDATA[S αγ +S αδ ]]> HE 7 33.7533.20 CH H 8 33.24 <![CDATA[T δδ ]]> EPE 9 30.92 <![CDATA[T βδ ]]> PPE 10 30.76 <![CDATA[S γγ ]]> XEEX 11 30.35 <![CDATA[S γδ ]]> XEEEE 12 29.95 <![CDATA[S δδ ]]> EEE 13 29.35 <![CDATA[3B4]]> H 14 28.94–28.38 CH P 15 27.43–27.27 <![CDATA[S βδ ]]> XEE 16 24.67-24.53 <![CDATA[S ββ ]]> XEX 17 23.44-23.35 <![CDATA[2B4]]> H 18 21.80–19.90 <![CDATA[CH3]]> P 19 14.22 <![CDATA[CH3]]> H

[0093] Ethylene content of propylene-ethylene copolymers by NMR: 13 C NMR spectra were obtained on a Bruker AV-600 spectrometer equipped with a cryoprobe, which was operated at 120°C in Fourier transform mode at 160.91 MHz. The peak of the Sββ carbon at 29.9 ppm (according to the nomenclature of "Monomer Sequence Distribution in Ethylene-Propylene Rubber Measured by 13C NMR. 3. Use of Reaction Probability Mode" CJ Carman, RA Harrington and CE Wilkes, "Macromolecules", 1977, 10, 536) was used as an internal reference. The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at 8% wt / v concentration at 120°C. Each spectrum was collected with a 90° pulse, and a 15 second delay between the pulse and CPD was used to remove 1H-13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz. Spectral assignments, triplet distributions, and composition were evaluated according to Kakugo (“Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared from delta-titanium trichloride-diethylaluminum chloride”).

[0094] Ethylene-propylene copolymers prepared with δ-titanium trichloride-diethylaluminum chloride)" M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 1982, 15, 1150) were carried out using the following equation:

[0095] PPP=100Tββ / S PPE=100Tβδ / S EPE=100Tδδ / S

[0096] PEP=100Sββ / S PEE=100Sβδ / S EEE=100(0.25Sγδ+0.5Sδδ) / S

[0097] S=Tββ+Tβδ+Tδδ+Sββ+Sβδ+0.25Sγδ+0.5Sδδ

[0098] The mole percentage of ethylene content was estimated using the following equation:

[0099] E%mol=100*[PEP+PEE+EEE]

[0100] The weight percent ethylene content was estimated using the following equation:

[0101]

[0102] Where P%mol is the molar percentage of propylene content, and MW E and MW P are the molecular weights of ethylene and propylene respectively.

[0103] The product of the reactivity ratios r1r2 is calculated according to Carman (CJ Carman, RA Harrington and CE Wilkes, Macromolecules, 1977; 10, 536):

[0104]

[0105] The stereoregularity of the propylene sequence is determined by PPP mmT ββ (28.90-29.65ppm) and total T ββ The ratio of (29.80-28.37ppm) was calculated as the mm content.

[0106] Hexene and ethylene content of propylene-hexene-ethylene terpolymer: 13 C NMR spectra were obtained on an AV-600 spectrometer operating at 150.91 MHz in Fourier transform mode at 120 °C. The peak of propylene CH was used as an internal reference at 28.83. The following parameters were used to obtain 13 C NMR spectrum:

[0107] Spectral Width (SW): 60ppm

[0108] Spectral center (O1): 30ppm

[0109] Decoupling sequence: WALTZ 65_64pl

[0110] Pulse program (1): ZGPG

[0111] Pulse length (P1)(2): For 90°

[0112] Total Points(TD): 32K

[0113] Relaxation delay (2): 15s

[0114] Number of transients (3): 1500

[0115] The total amount of 1-hexene and ethylene was calculated as a mole percent from the dyads using the following relationship:

[0116] [P] = PP + 0.5PH + 0.5PE

[0117] [H]=HH+0.5PH

[0118] [E] = EE + 0.5PE

[0119] Propylene / 1-hexene / ethylene copolymer 13 The assignments of C NMR spectra were calculated according to the following table:

[0120] area Chemical shift distribute sequence 1 46.93–46.00 <![CDATA[S αα ]]> PP 2 44.50–43.82 <![CDATA[S αα ]]> PH 3 41.34-4.23 <![CDATA[S αα ]]> HH 4 38.00-37.40 <![CDATA[S αγ +S αδ ]]> PE 5 35.70-35.0 <![CDATA[4B4]]> H 6 35.00-34.53 <![CDATA[S αγ +S αδ ]]> HE 7 33.7533.20 CH H 8 33.24 <![CDATA[T δδ ]]> EPE 9 30.92 <![CDATA[T βδ ]]> PPE 10 30.76 <![CDATA[S γγ ]]> XEEX 11 30.35 <![CDATA[S γδ ]]> XEEEE 12 29.95 <![CDATA[S δδ ]]> EEE 13 29.35 <![CDATA[3B4]]> H 14 28.94–28.38 CH P 15 27.43–27.27 <![CDATA[S βδ ]]> XEE 16 24.67-24.53 <![CDATA[S ββ ]]> XEX 17 23.44-23.35 <![CDATA[2B4]]> H 18 21.80–19.90 <![CDATA[CH3]]> P 19 14.22 <![CDATA[CH3]]> H

[0121] Comonomer content of polybutene: 13C NMR spectra were obtained on a Bruker AV-600 spectrometer equipped with a cryoprobe, which was operated in Fourier transform mode at 120°C. The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at 8% wt / v concentration at 120°C. Each spectrum was collected with a 90° pulse, with a 15 second delay between the pulse and CPD to remove 1H-13C coupling. The spectrometer was operated at 160.91 MHz. The peak of Sδδ carbon at 29.9 ppm (according to the nomenclature of "Monomer sequence distribution in ethylene-propylene rubber measured by 13C NMR. 3. Use of reaction probability model" CJ Carman, RA Harrington and CE Wilkes, "Macromolecules", 1977, 10, 536) was used as an internal reference. 512 transients were stored in 32K data points using a spectral window of 9000 Hz.

[0122] The spectra were assigned values, ternary distributions and compositions were evaluated 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)] using the following:

[0123] BBB=100T ββ / S BBE=100T βδ / S EBE=100P δδ / S

[0124] BEB=100S ββ / S BEE=100S αδ / S EEE=100(0.25S γδ +0.5S δδ ) / S

[0125] S=T ββ +T βδ +P δδ +S ββ +S αδ +0.25S γδ +0.5S δδ

[0126] The total amount of 1-butene and ethylene in mole percent was calculated from the triad using the following relationship:

[0127] [E]=EEE+BEE+BEB

[0128] [B]=BBB+BBE+EBE

[0129] The weight percent ethylene content (E% wt) was calculated using the following equation:

[0130]

[0131] in

[0132] [B]mol = molar percentage of 1-butene content;

[0133] MWE = molecular weight of ethylene

[0134] MWB = molecular weight of 1-butene.

[0135] Molecular weight distribution Mw / Mn: The average Mn and Mw and the Mw / Mn derived therefrom were determined using a Waters GPCV 2000 device equipped with a column set of four PLgel Olexis mixed gels (Polymer Laboratories) and an IR4 infrared detector (PolymerChar). The dimensions of the column were 300×7.5 mm, and the particle size was 13 μm. The mobile phase used was 1-2-4-trichlorobenzene (TCB), and the flow rate was maintained at 1.0 ml / min. All measurements were performed at 150°C. The solution concentration in TCB was 0.1 g / dl, and 0.1 g / l of 2,6-di-tert-butyl-p-cresol was added to prevent degradation. For GPC calculations, a universal calibration curve was obtained using 10 polystyrene (PS) standard samples (peak molecular weights of 580 to 8,500,000) provided by Polymer Laboratories. A third-order polynomial fit was used to interpolate the experimental data and obtain the associated calibration curve. Empower (Waters) was used for data acquisition and processing. The molecular weight distribution and the related average molecular weight were determined using the Mark-Houwink relationship: the K values ​​for PS and PB were KPS=1.21×10-4dL / g and KPB=1.78×10-4dL / g, respectively, while the Mark-Houwink index α=0.706 for PS and the Mark-Houwink index α=0.725 for PB were used. For butene-1 / ethylene copolymers, for data evaluation, it was assumed that the composition was constant over the entire molecular weight range, and the K value of the Mark-Houwink relationship was calculated using a linear combination reported as follows:

[0136] K EB =x E K PE +x P K PB

[0137] Where K EB is the constant of the copolymer, K PE (4.06×10 -4 , dL / g) and K PB (1.78×10 -4 dl / g) are constants for polyethylene and polybutene, and xE and xB are the weight % contents of ethylene and butene-1. The Mark-Houwink index α=0.725 is used for all butene-1 / ethylene copolymers, regardless of their composition.

[0138] Melting Temperature: Measured according to method ISO 11357-3:2018. Polypropylene and polypropylene compositions : The scanning rate was 20°C / min in cooling and heating, under nitrogen flow, for samples weighing 5-7 mg. The instrument was calibrated with indium. Gather Butene : To determine the melting temperature (Tm(I)) of polybutene form I, the sample was melted, held at 200°C for 5 minutes and then cooled to 20°C at a cooling rate of 10°C / min. The sample was then stored at room temperature for 10 days. After 10 days, the sample was subjected to DSC, cooled to -20°C and then heated at 200°C at a scanning rate corresponding to 10°C / min. In this heating run, the first peak temperature from the lower temperature side of the thermogram was taken as the melting temperature Tm(I).

[0139] Flexural modulus: Determined according to method ISO 178:2010 on injection molded test specimens (80×10×4 mm) for propylene polymers or on compression molded specimens for butene polymers obtained according to method ISO 1873-2:2007. Prior to testing, specimens of butene copolymers were conditioned at 23° C. for 10 days.

[0140] Preparation of BOPP film test specimens. A film with a thickness of 50 μm was prepared by extruding each test composition in a single screw Collin extruder (screw length / diameter ratio of 1:25) at a film drawing speed of 7 m / min and a melt temperature of 210°C to 250°C. Each layer of film was superimposed on a 1000 μm thick propylene homopolymer film having a xylene insoluble fraction of 97 wt.% and an MFR of 2.0 g / 10 min (ISO1133-1:2011, 230°C / 2.16 kg). The superimposed films were heated at 200°C under 35 kg×cm 2 The laminate was stretched 7 times in both longitudinal and transverse directions (ie, biaxially) 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).

[0141] Seal initiation temperature on BOPP film: A film strip of 6 cm wide and 35 cm long was cut from the center of the BOPP film. The film was superimposed with a BOPP film made of PP homopolymer. The superimposed specimens were sealed along one of the 2 cm sides using a Brugger Feinmechanik sealer model HSG-ETK 745. The sealing time was 5 seconds at a pressure of 0.14 MPa (20 psi). The initial sealing temperature was about 10°C lower than the melting temperature of the test composition. The sealing strip was cut into 6 specimens of 15 mm width, which were long enough to be tensile tested in the tensile tester fixture. The seal strength and load cell capacity of 100 N, lateral speed of 100 mm / min and clamping distance of 50 mm were tested. The results are expressed as the average value of the maximum seal strength (N). They were left to cool and then their unsealed ends were attached to the Instron machine, where they were tested at a pulling speed of 50 mm / min.

[0142] The test was then repeated by varying the temperature as follows:

[0143] If seal strength is <1.5N, increase temperature.

[0144] If seal strength >1.5N, reduce temperature.

[0145] If the seal strength is close to the target by a selection step of 1°C, if the strength is away from the target by a selection step of 2°C, the temperature change must be adjusted stepwise.

[0146] The target seal strength (SIT) is defined as the lowest temperature at which a seal strength greater than or equal to 1.5N is achieved.

[0147] raw material

[0148] Irganox1010 : Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) sold by BASF.

[0149] Irgafos168 : tris(2,4-di-tert-butylphenyl)phosphite sold by BASF.

[0150] PB1(B): a copolymer of butene-1 and ethylene, containing 3.5% by weight of ethylene, and having a Tm(I) of 94°C, a molecular weight distribution Mw / Mn of 5.6, a melt flow rate of 3.1 g / 10 min. (ISO 1133-1:2011, 190°C / 2.16 kg), and a flexural modulus (ISO 178:2010) of 120 MPa. Using butene-1 as a liquid medium and a Ziegler-Natta catalyst system according to Example 11 of patent WO2004 / 048424, a butene-1 copolymer was obtained by sequential polymerization in two reactors under the following polymerization conditions in the first reactor: temperature 75°C and hydrogen / butene feed ratio 1000 ppmV. After 2.5 hours, the polymerization contents of the first reactor were transferred to the second reactor, where copolymerization was continued under the same conditions, the only difference being the interruption of the ethylene feed. The polymerization was stopped after 2 hours.

[0151] PB2(B) : Copolymer of butene-1 and ethylene, containing 3.5 wt% ethylene, and having 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 (ISO 178:2010) of 130 MPa.

[0152] Propylene polymer (A)

[0153] Procedure for the preparation of spherical adduct: Microspherical MgCl2.pC2H5OH adduct was prepared according to the method described in Comparative Example 5 of WO98 / 44009, except that BiCl3 was added in powder form before the feed oil and in an amount of 3 mol% relative to magnesium.

[0154] Procedure for preparing solid catalyst component: The solid catalyst component was prepared according to Example 1 of EP728769 with the following differences:

[0155] - the second and third titanation were carried out at 110°C (instead of 120°C); and

[0156] - Use MgCl in the form of spherical solid particles with a maximum diameter less than or equal to 65 microns (instead of 50 microns) 2.3· C2H5OH.

[0157] Catalyst system and prepolymerization treatment: Before introducing it into the polymerization reactor, the above solid catalyst component was contacted with triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) as external donors at 15°C for about 6 minutes.

[0158] The catalyst system was then prepolymerized by keeping it in liquid propylene suspension at 20°C for about 20 minutes before being introduced into the polymerization reactor.

[0159] Polymerization: In the first gas phase polymerization reactor, a propylene-hexene copolymer (component (A)) is produced by feeding a gaseous prepolymerization catalyst system, hydrogen, propylene and 1-hexene at a continuous and constant flow rate. The propylene copolymer produced in the first reactor is discharged in a continuous flow and introduced into the second gas phase polymerization reactor in a continuous flow together with a quantitative constant flow of gaseous hydrogen, hexene, ethylene and propylene. The propylene terpolymer produced in the second reactor is discharged in a continuous flow and, after having been purged of unreacted monomers, is introduced into the third gas phase polymerization reactor in a continuous flow together with a quantitative constant flow of gaseous hydrogen, hexene and propylene. The polymerization conditions are reported in Table 1.

[0160] Table 1

[0161]

[0162]

[0163] To the polymer obtained from the polymerization run was added 0.05 wt.% Irganox 1010, 0.1 wt.% Irgafos 168, 0.05% calcium stearate, wherein the amount of additives is based on the total weight of the polymer including additives, and pelletized. Table 2 illustrates the characteristics of the propylene polymer.

[0164] Table 2

[0165]

[0166]

[0167] Examples E1 to E3

[0168] The propylene polymer (A) and the polybutene (B) were melt blended in the proportions shown in Table 3 in a twin screw extruder (Werner 58, model WP ZSK-58) at a rotation speed of 220 rpm and an extruder output of 220 kg / hour.

[0169] The thermal and sealing properties of the polypropylene composition are graphically shown in Table 3. The polypropylene composition also exhibited a significantly low number of fisheyes on the cast film.

[0170] Table 3

[0171]

Claims

1. A polypropylene composition (I), comprising: (A) at least 90.0 wt. % of a propylene polymer comprising (based on the weight of (a) + (b) + (c)): (a) 20 to 44 wt% of a propylene-hexene copolymer comprising 5.0 to 8.3 wt% of hexene-derived units, based on the weight of component (a), and having a melt flow rate (MFR(a)) in the range of 3.5 to 8.5 g / 10 min measured according to ISO 1133-1:2011 (230°C / 2.16 kg); (b) 25 to 45 wt% of a propylene-hexene-ethylene terpolymer comprising 7.2 to 12.0 wt% of hexene-derived units and 0.5 to 2.5 wt% of ethylene-derived units, wherein the melt flow rate (MFR(a+b)) of component 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; and (c) 25 to 50 wt.% of a propylene-ethylene copolymer comprising 3.5 to 8.7 wt.% of ethylene-derived units, wherein the melt flow rate of components (a)+(b)+(c) measured according to ISO 1133-1:2011 (230°C / 2.16kg) ranges from 3.5 to 12.0 g / 10 min, and wherein the propylene polymer (A) has: (i) a xylene solubles content in the range of 13.0 wt. % to 25.0 wt. % based on the weight of (a) + (b) + (c) at 25°C; and (ii) a melting point ranging from 122°C to 132°C; and (B) up to and including 10.0 wt. % of a polybutene selected from butene homopolymers, butene copolymers having up to and including 5.0 wt. % of units derived from ethylene and / or propylene, based on the weight of component (B), and mixtures thereof, The amounts of (A) and (B) are based on the total weight of (A) + (B).

2. The polypropylene composition (I) according to claim 1, comprising: - at least 90.0 wt.-%, preferably 90.0 to 99.5 wt.-%, more preferably 93.0 to 99.0 wt.-%, still more preferably 95.0 to 98.0 wt.-% of said propylene polymer (A), and - up to and including 10.0 wt. %, preferably 0.5 to 10.0 wt. %, more preferably 1.0 to 7.0 wt. %, still more preferably 2.0 to 5.0 wt. % of said polybutene, The amounts of (A) and (B) are based on the total weight of (A) + (B).

3. The polypropylene composition (I) according to claim 1 or 2, wherein the propylene polymer (A) comprises (based on the weight of (a)+(b)+(c)): (a) 20 to 44 wt%, preferably 27 to 40 wt%, more preferably 29 to 35 wt% of a propylene-hexene copolymer based on the weight of the component (a) - comprises from 5.0 to 8.3 wt. %, preferably from 6.3 to 7.8 wt. %, more preferably from 6.5 to 7.4 wt. % 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, preferably 4.4 to 8.0 g / 10 min, more preferably 5.0 to 7.0 g / 10 min, measured according to ISO 1133-1:2011 (230°C / 2.16 kg); (b) 25 to 45 wt%, preferably 35 to 40 wt%, more preferably 36 to 39 wt% of a propylene-hexene-ethylene terpolymer comprising - 7.2 to 12.0 wt. %, preferably 7.5 to 9.5 wt. %, more preferably 8.2 to 9.1 wt. % of hexene-derived units, and - 0.5 to 2.5 wt. %, preferably 0.7 to 2.2 wt. %, more preferably 0.8 to 2.0 wt. % of ethylene-derived units, wherein - the melt flow rate (MFR (a+b)) of components (a) + (b) measured according to ISO 1133-1:2011 (230°C / 2.16kg) is in the range of 3.5 to 8.5 g / 10min, preferably 4.4 to 8.0 g / 10min, more preferably 5.0 to 7.0 g / 10min, and - the amounts of hexene and ethylene are based on the weight of (b); and (c) 25 to 50 wt%, preferably 27 to 40 wt%, more preferably 29 to 35 wt% of a propylene-ethylene copolymer comprising - 3.5 to 8.7 wt. %, preferably 4.5 to 8.4 wt. %, based on the weight of (c), of ethylene-derived units, in - the melt flow rate of components (a) + (b) + (c) measured according to ISO 1133-1:2011 (230°C / 2.16kg) is in the range of 3.5 to 12.0 g / 10 min, preferably 4.4 to 8.0 g / 10 min, more preferably in the range of 5.0 to 8.5 g / 10 min, and The propylene polymer (A) has: (ii) a xylene solubles content at 25°C ranging from 13.0 wt% to 25.0 wt%, preferably from 14.0 wt% to 23.0 wt%, more preferably from 15.0 wt% to 20.0 wt%; and (ii) a melting point ranging from 122°C to 132°C, preferably from 125°C to 131°C, more preferably from 126°C to 130°C.

4. The polypropylene composition (I) according to any one of claims 1 to 3, wherein component (B) is a butene-ethylene copolymer.

5. The polypropylene composition (I) according to claim 4, wherein the component (B) is a butene-ethylene copolymer having at least one, preferably all, of the following properties: - a content of units derived from ethylene in the range of 1.0 to 4.5 wt.-%, preferably 1.5 to 4.5 wt.-%, more preferably 2.0 to 4.0 wt.-%, still more preferably 2.5 to 3.5 wt.-%, based on the weight of (B); and / or - the melting temperature Tm(I) of form I measured by DSC according to method ISO 11357-3:2018 is below 100°C, preferably in the range of 80°C to below 100°C, more preferably from 90°C to 97°C; and / or - a melt flow rate in the range of 1.0 to 6.0 g / 10 min, preferably 2.0 to 5.0 g / 10 min, still more preferably 3.0 to 4.5 g / 10 min, measured according to ISO 1133-1:2011 (190°C / 2.16 kg); and / or - Flexural modulus measured according to ISO 178:2010 equal to or higher than 80 MPa, preferably ranging from 80 to 250 MPa, more preferably from 100 to 210 MPa.

6. The polypropylene composition (I) according to any one of claims 1 to 5, further comprising up to and including 5.0 wt.-%, more preferably 0.01 wt.-% to 5.0 wt.-% of at least one additive (C) selected from the group consisting of nucleating agents, antistatic agents, antioxidants, light stabilizers, slip agents, antacids, melt stabilizers and combinations thereof, the amount of additive being based on the total weight of the polypropylene composition (I) including the additive.

7. The polypropylene composition (I) according to any one of claims 1 to 6, having at least one, preferably all, of the following properties: - a seal initiation temperature (SIT) measured on a BOPP film in the range of 70 to 85°C, more preferably 72 to 83°C; and / or -ΔTm-SIT values ​​range from 40.0 to 60.0°C, preferably from 45.0 to 55°C, wherein Tm is the melting temperature of the polypropylene composition (I) and SIT is the seal initiation temperature measured on a BOPP film.

8. A film or sheet comprising the polypropylene composition (I) as defined in any one of claims 1 to 7.

9. The film or sheet according to claim 8, wherein the film or sheet is multilayered and the polypropylene composition (I) is comprised in at least one skin layer.

10. The film or sheet according to claim 8 or 9, wherein the film is a cast film or a BOPP film.

Images