Propylene-based polymer composition

Abstract

A polymer composition comprising: A) 70 wt% to 95 wt% of a propylene-based polymer composition comprising: a) 15 wt% to 35 wt% of a copolymer of propylene and 1-hexene containing 6.2 to 8.5 wt% of 1-hexene-derived units; b) 15 wt% to 35 wt% of a copolymer of propylene and 1-hexene containing 10.4 wt% to 14.5 wt% of 1-hexene-derived units; c) 38 wt% to 68 wt% of a propylene-ethylene copolymer, wherein the sum of the amounts of a), b), and c) is 100; and B) 5.0 wt% to 30.0 wt% of a copolymer of 1-butene and ethylene containing 3.0 wt% to 4.2 wt% of ethylene-derived units; wherein the sum of the amounts of A) and B) is 100 wt%.

Description

Technical Field

[0001] The present disclosure relates to propylene compositions having low seal initiation temperature and good hot tack fit for the production of films, in particular biaxially oriented polypropylene films (BOPP) and cast films. Background Art

[0002] Copolymers of propylene and 1-hexene are known in the art, for example WO 2006 / 002778 relates to copolymers of propylene and 1-hexene having 0.2 to 5 wt% of 1-hexene-derived units. The copolymers have a unimodal molecular weight distribution and are used in pipeline 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 producing films, in particular biaxially oriented polypropylene (BOPP) films and cast films, having a low seal initiation temperature (SIT) and high clarity. The obtained seal initiation temperature is still unsatisfactory and can be reduced.

[0004] WO 2018 / 202396 relates to a propylene polymer composition comprising: 35 to 65 wt% of a copolymer of propylene and 1-hexene containing 10.2 to 13 wt% of 1-hexene-derived units; and 35 to 65 wt% of a copolymer of propylene and ethylene containing 1.5 to 6.5 wt% of ethylene-derived units. Even though the exemplified compositions exhibit very low SIT, the xylene soluble content is very high, and as shown in comparative examples, the amount of gel can be reduced.

[0005] Such polypropylene compositions are widely used in the packaging sector, in particular for the production of films in the food packaging sector, but also for the packaging of non-food products and for the production of non-packaged items.

[0006] Examples of packaging are primary packaging for hygiene products, textiles, magazines, mailing films, secondary collation packaging, shrink wrap films and sleeves, stretch wrap films and sleeves, form-fill-seal packaging films for dispensing various types of articles such as bags, pouches or sachets, vacuum formed blisters.

[0007] An important feature of these films is the very low seal initiation temperature without loosening other film characteristics such as hot tack.

[0008] WO 2011 / 036077 relates to a heat-sealable polyolefin film comprising a heterophasic propylene copolymer and a butene-1 (co)polymer having a butene-1 derived unit content of 75 wt% or more and a flexural modulus (MEF) of 70 MPa or less.

[0009] WO2018 / 211107 relates to a polyolefin composition comprising a random propylene copolymer and a 1-butene polymer, wherein the 1-butene polymer is preferably a 1-butene copolymer having a 1-butene-derived unit content of less than 50 wt%.

[0010] Applicants have discovered that the seal initiation temperature of certain propylene-based polymer compositions can be lowered by using 1-butene copolymers having specific characteristics. Summary of the Invention

[0011] Therefore, the object of the present disclosure is a polymer composition comprising:

[0012] A) 70 wt% to 95 wt% of a propylene-based polymer composition comprising:

[0013] a) 15 to 35 wt% of a copolymer of propylene and 1-hexene, containing 6.2 to 8.5 wt% of 1-hexene-derived units and having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) of 3.5 to 8.5 g / 10 min;

[0014] b) 15 to 35 wt% of a copolymer of propylene and 1-hexene, containing 10.4 to 14.5 wt% of 1-hexene-derived units and having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) of 3.5 to 8.5 g / 10 min;

[0015] c) 38 to 68 wt% of a copolymer of propylene and ethylene containing 3.4 to 5.7 wt% of ethylene-derived units, having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) of 3.5 to 12.0 g / 10 min and a xylene solubles content at 25°C of 3.7 to 7.8 wt%;

[0016] The sum of the amounts of components a), b) and c) in the propylene-based composition is 100 wt%;

[0017] in:

[0018] i) the total amount of 1-hexene-derived units of components a) and b) is from 9.4 wt% to 11.6 wt%;

[0019] ii) the propylene-based polymer composition has a xylene soluble content at 25° C. of 14.2 wt % to 19.3 wt %;

[0020] iii) the composition has a 1-hexene content of 3.7 wt% to 6.4 wt%;

[0021] iv) The composition has a melting point of 128°C to 135°C.

[0022] B) 5.0 to 30.0 wt% of a copolymer of 1-butene and ethylene containing 3.0 to 4.2 wt% of ethylene-derived units; the copolymer of 1-butene and ethylene having:

[0023] - Melt flow rate: measured according to ISO 1133-1 (190° C., 2.16 kg), ranging from 1.0 to 5.5 g / 10 min;

[0024] Flexural modulus measured according to ISO 178 in the range of 80 MPa to 250 MPa;

[0025] The melting temperature range measured according to ISO 11357-3 is 83°C to 108°C, Form I.

[0026] The sum of the amounts of A) and B) is 100 wt%. DETAILED DESCRIPTION

[0027] Therefore, the object of the present disclosure is a polymer composition comprising:

[0028] A) 70.0 wt% to 95.0 wt%, preferably 74.0 wt% to 87.0 wt%, more preferably 77.0 wt% to 86.0 wt% of a propylene-based polymer composition comprising:

[0029] a) 15 wt% to 35 wt%, preferably 20 wt% to 31 wt%; more preferably 22 wt% to 28 wt% of a copolymer of propylene and 1-hexene containing 6.2 wt% to 8.5 wt%, preferably 6.8 wt% to 8.1 wt%; more preferably 7.1 wt% to 7.9 wt% of 1-hexene-derived units and having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) of 3.5 to 8.5 g / 10 min, preferably 4.4 to 8.0 g / 10 min; more preferably 5.0 to 7.08.5 g / 10 min;

[0030] b) 15 wt% to 35 wt%, preferably 20 wt% to 31 wt%; more preferably 22 wt% to 28 wt% of a copolymer of propylene and 1-hexene containing 10.4 wt% to 14.5 wt%; preferably 11.2 wt% to 13.9 wt%; more preferably 11.6 wt% to 13.3 wt% of 1-hexene-derived units and having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) 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 8.5 g / 10 min;

[0031] c) 38 wt% to 68 wt%; preferably 42 wt% to 62 wt%; more preferably 45 wt% to 58 wt% of a copolymer of propylene and ethylene containing 3.4 wt% to 5.7 wt%; preferably 3.9 wt% to 5.1 wt%; more preferably 4.2 wt% to 4.9 wt% of ethylene-derived units, having a melt flow rate (MFR, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg) 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 8.5 g / 10 min and a xylene solubles content at 25°C of 3.7 wt% to 7.8 wt%; preferably 4.1 wt% to 6.8 wt%, more preferably 4.6 wt% to 6.2 wt%;

[0032] The sum of the amounts of components a), b) and c) in the propylene-based composition is 100 wt%;

[0033] in:

[0034] i) the total amount of 1-hexene-derived units of components a) and b) is from 9.4 wt% to 11.6 wt%; preferably from 9.5 wt% to 11.5 wt%; more preferably from 9.6 wt% to 10.8 wt%;

[0035] ii) the propylene-based polymer composition has a xylene soluble content at 25°C of 14.2 wt% to 19.3 wt%; preferably 15.3 wt% to 18.7 wt%; more preferably 16.2 wt% to 18.1 wt%;

[0036] iii) the 1-hexene derived unit content of the composition is 3.7 wt% to 6.4 wt%; preferably 3.9 wt% to 5.4 wt%; more preferably 4.2 wt% to 5.2 wt%

[0037] iv) the melting point of the composition is from 128°C to 135°C; preferably from 129°C to 133°C;

[0038] B) 5.0 wt% to 30.0 wt%; preferably 13.0 wt% to 26.0 wt%; more preferably 14.0 wt% to 23 wt% of a copolymer of 1-butene and ethylene containing 3.0 wt% to 4.2 wt%, preferably 3.2 wt% to 4.0 wt%; more preferably 3.3 wt% to 3.9 wt% of ethylene-derived units; said copolymer of 1-butene and ethylene having:

[0039] - melt flow rate: 1.0 to 5.5 g / 10 min, preferably 2.1 to 4.8 g / 10 min, more preferably 2.4 to 4.1 g / 10 min, measured according to ISO 1133-1 (190° C., 2.16 kg);

[0040] Flexural modulus measured according to ISO 178 of 50 to 250 MPa; preferably 80 to 210 MPa; more preferably 92 to 174 MPa.

[0041] The melting temperature measured according to ISO 11357-3 is from 83°C to 108°C, preferably from 84°C to 103°C; more preferably in the range of 88°C to 100°C, Form I;

[0042] The sum of the amounts of A) and B) is 100 wt%.

[0043] The term "copolymer" as used in this patent application refers to polymers containing units derived from only two comonomers, such as 1-butene and ethylene, propylene 1-hexene, propylene and ethylene.

[0044] Component B) is a commercially available 1-butene ethylene copolymer, such as Koattro DP8310M sold by LyondellBasell, and can be prepared according to methods known in the art by using a Ziegler-Natta catalyst.

[0045] The polymer compositions of the present disclosure can be prepared by mechanically blending component A) and component B) according to methods well known in the art.

[0046] The compositions of the present disclosure have very low seal initiation temperatures (SIT), making the materials advantageously useful in the production of films, particularly cast films or BOPP films.

[0047] In particular, for the compositions of the present disclosure, the difference between the melting point and the SIT of the composition is particularly high. The relatively high melting point allows for better processability of the polymer, particularly when used to obtain films, while the low SIT value improves the use of the film in sealing applications.

[0048] Furthermore, the compositions of the present disclosure also have improved hot tack, which, along with the high melting point and variable low haze, allow the use of the material as a sealant layer for multilayer films.

[0049] Therefore, another object of the present disclosure is a film comprising the polymer composition of the present disclosure, in particular, another object of the present disclosure is a multilayer film wherein the sealing layer comprises the polymer composition of the present disclosure.

[0050] The multilayer film of the present disclosure is characterized in that it has at least a sealant layer comprising the polymer composition of the present disclosure. The remaining layers can be formed from any material known in the art for use in multilayer films or laminated products. Thus, for example, each layer can be formed from a polypropylene homopolymer or copolymer or a polyethylene homopolymer or copolymer or other types of polymers (such as EVA).

[0051] The combination and number of layers of the multilayer structure are not particularly limited. The number is generally 3 to 11 layers or even more, preferably 3 to 9 layers, and more preferably 3 to 7 layers, and more preferably 3 to 5 layers, and combinations including C / B / A, C / B / C / B / A, and C / B / C / D / C / B / A are possible, provided that at least one sealing layer A comprises the polymer composition of the present disclosure.

[0052] The preferred layers of the multilayer film of the present disclosure are 3 layers or 5 layers, wherein the sealing layer comprises, preferably consists of, the polymer composition of the present disclosure.

[0053] Preferably, the SIT value is comprised between 70° C. and 55° C.; preferably between 67° C. and 56° C. The difference between the melting point and the SIT (Tm-SIT) is preferably between 60° C. and 75° C.; preferably in the range of 63° C. to 73° C.

[0054] Components a) + b) of the composition of the present disclosure are also preferably endowed with a 1-hexene-derived unit content in the xylene-soluble fraction comprising between 18.0 and 32.0 wt%; preferably between 21.0 and 30.0 wt%. A high content of comonomer in the xylene-soluble fraction improves the processability of the composition.

[0055] Component c) of the composition of the present disclosure is preferably endowed with a content of ethylene-derived units comprised between 10.0% and 17.0% by weight, preferably between 11.0% and 16.0% by weight, and more preferably between 13.0% and 15.0% by weight, in the fraction soluble in xylene at 25° C. This feature improves the processability of the composition for obtaining films.

[0056] Components a), b) and c) of the propylene polymer composition are obtained by a polymerization process carried out in the presence of a catalyst comprising the reaction product between:

[0057] A solid catalyst component comprising Ti, Mg, Cl and at least one electron donor compound, characterized in that it contains 0.1-50 wt% of Bi relative to the total weight of the solid catalyst component; the external donor is preferably an ester of glutaric acid, preferably an alkyl ester of glutaric acid, such as 1,3,3-dipropyl glutarate; preferably, the ester of glutaric acid is used in a mixture with 9,9-bis(alkoxymethyl)fluorene, such as 9,9-bis(methoxymethyl)fluorene; preferably, the molar ratio between the ester of glutaric acid and 9,9-bis(alkoxymethyl)fluorene is from 50:50 to 90:10; preferably from 60:40 to 80:20; more preferably from 65:35 to 75:25; the alkyl group is a C1-C10 alkyl group, such as methyl, ethylpropyl; a butyl group;

[0058] (ii) an alkylaluminum compound; and

[0059] (iii) external electron donor compounds having the following general formula:

[0060] (R 1 ) a Si(OR 2 ) b

[0061] where R 1 and R 2 Independently selected from alkyl or cycloalkyl groups having 1 to 8 carbon atoms and a+b=4.

[0062] Preferably, the content of Bi in the catalyst component is from 0.5 to 40 wt%, more preferably from 1 to 35 wt%, especially from 2 to 25 wt%, in a very particular embodiment from 2 to 20 wt%.

[0063] The particles of the solid component have a substantially spherical morphology and an average diameter of 5 to 150 μm, preferably 20 to 100 μm and more preferably 30 to 90 μm. As particles having a substantially spherical morphology, it is meant that the ratio between the major axis and the minor axis is equal to or lower than 1.5, and preferably lower than 1.3.

[0064] Generally, the amount of Mg is preferably 8 to 30 wt%, more preferably 10 to 25 wt%.

[0065] Typically, the amount of Ti is 0.5 to 5 wt%, more preferably 0.7 to 3 wt%.

[0066] The Mg / Ti molar ratio is preferably equal to or higher than 13, preferably between 14 and 40, and more preferably between 15 and 40. Correspondingly, the Mg / donor molar ratio is preferably higher than 16, more preferably higher than 17, typically between 18 and 50.

[0067] The Bi atom is preferably derived from one or more Bi compounds that do not have a Bi-carbon bond. Specifically, the Bi compound can be selected from Bi halides, Bi carbonates, Bi acetates, Bi nitrates, Bi oxides, Bi sulfates, and Bi sulfides. Preferably, the valence of Bi is 3 + Among the Bi halides, preferred compounds are Bi trichloride and Bi tribromide. The most preferred Bi compound is BiCl3.

[0068] The preparation of the solid catalyst component can be carried out according to several methods.

[0069] According to one method, the solid catalyst component can be prepared by making the formula Ti(OR) q-y X y A titanium compound of the formula MgCl2·pROH wherein q is the valence of titanium and y is a number between 1 and q, preferably TiCl4, is reacted with magnesium chloride derived from an adduct of the formula MgCl2·pROH wherein p is a number between 0.1 and 6, preferably from 2 to 3.5, and R is a hydrocarbon radical having 1 to 18 carbon atoms. The adduct can be prepared in spherical form by mixing an alcohol and magnesium chloride, operating under stirring conditions at the melting temperature of the adduct (100-130° C.). The adduct is then mixed with an inert hydrocarbon immiscible with the adduct, thereby producing an emulsion which is rapidly quenched, causing the adduct to solidify in the form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP 4,399,054 and USP 4,469,648. The resulting adduct can be reacted directly with the Ti compound, or it can be previously subjected to a thermally controlled dealcoholation (80-130°C) to obtain an adduct in which the number of moles of alcohol is generally less than 3, preferably 0.1-2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or not) in cold TiCl4 (generally 0°C); heating the mixture to 80-130°C and maintaining it at this temperature for 0.5-2 hours. The treatment with TiCl4 can be carried out one or more times. The electron donor compound can be added during the treatment with TiCl4 in the desired ratio.

[0070] Several methods can be used to incorporate one or more Bi compounds during catalyst preparation. According to a preferred option, the Bi compound is incorporated directly into the MgCl2·pROH adduct during its preparation. In particular, the Bi compound can be added during the initial stages of adduct preparation by mixing it with MgCl2 and an alcohol. Alternatively, it can be added to the molten adduct prior to the emulsification step. The amount of Bi introduced is 0.1 to 1 mol per mol of Mg in the adduct. Preferred Bi compounds to be incorporated directly into the MgCl2·pROH adduct are Bi halides, in particular BiCl3.

[0071] The alkyl-Al compound (ii) is preferably selected from trialkylaluminum compounds, such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. Alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides, such as AlEt2Cl and Al2Et3Cl3, may also be used, possibly mixed with the above-mentioned trialkylaluminums. The Al / Ti ratio is higher than 1 and is generally between 50 and 2000.

[0072] The external electron donor compound (iii) is a silicon compound having the following general formula:

[0073] (R 1 ) a Si(OR 2 ) b (II)

[0074] where R 1 and R 2 Independently selected from alkyl or cycloalkyl groups having 1 to 8 carbon atoms, optionally containing heteroatoms, wherein a+b=4.

[0075] Useful examples of silicon compounds of formula II are (tert-butyl)2Si(OCH3)2, (cyclopentyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si(OCH3)2.

[0076] The external electron donor compound (c) is used in such an amount that the molar ratio of the organoaluminium compound to the external electron donor compound (iii) is 0.1-200, preferably 1-100, more preferably 3-50.

[0077] The polymerization process can be continuous or batch, carried out according to known techniques and in the gas phase, or in the liquid phase with or without an inert diluent, or by mixed liquid-gas techniques. The polymerization is preferably carried out in the gas phase in three reactors, one for each component of the composition. Components a) and b) are preferably obtained separately in the first two reactors, while component c) is obtained in the third and last reactor.

[0078] Polymerization time, pressure and temperature are not critical, however it is optimal if the temperature is from 20 to 100° C. The pressure may be atmospheric or higher.

[0079] As already mentioned, the molecular weight is regulated by using known regulators, in particular hydrogen.

[0080] The compositions of the present disclosure may also contain additives commonly used in olefin polymers, such as nucleating and clarifying agents and processing aids.

[0081] The compositions of the present disclosure are preferably characterized by a gel number No (>0.1 mm) of less than 250; preferably less than 150. The gel number indicates the homogeneity of the product: the lower the number of gels, the more homogeneous the polymer.

[0082] The propylene polymer compositions of the present disclosure can be advantageously used to produce films. Preferably, cast or BOPP films are monolayer or multilayer, wherein at least one layer comprises the composition of the present disclosure.

[0083] Example

[0084] The following examples are given to illustrate the present invention and not for limiting purposes.

[0085] The data related to the polymeric materials and films of the examples were determined by the methods reported below.

[0086] Melting and crystallization temperature (ISO 11357-2013)

[0087] The determination was made by differential scanning calorimetry (DSC) according to ISO 11357-20133 at a scanning rate of 20° C. / min, with cooling and heating, on samples weighing 5 to 7 mg, under an inert N 2 flow. Indium was used for instrument calibration.

[0088] Melting temperature of component B)

[0089] The melting temperature TmI is the melting temperature attributable to the crystalline form I of the copolymer. To determine TmI, a sample of the copolymer is melted, then cooled to 20° C. at a cooling rate of 10° C. / min, kept at room temperature for 10 days, and then subjected to differential scanning calorimetry (DSC) analysis by cooling to −20° C. and then heating to 200° C. at a scanning rate corresponding to 10° C. / min. In this heating run, the peak temperature is taken as the melting temperature (TmI).

[0090] Melt flow rate (MFR)

[0091] Measured according to ASTM D 1238-13 at 230°C and a load of 2.16 kg or ISO 1133-1 at 190°C and a load of 2.16 kg.

[0092] Solubility in xylene at 25°C

[0093] Xylene solubles were measured according to ISO 16 152-2005; the solution volume was 250 ml, the solution was settled at 25°C for 20 minutes, 10 minutes of which the solution was stirred (magnetic stirrer), and dried at 70°C.

[0094] Propylene / ethylene copolymer 13 C NMR

[0095] 13 C NMR spectra were obtained on a Bruker Av-600 spectrometer equipped with a cryoprobe, operating at 160.91 MHz in Fourier transform mode at 120 °C.

[0096] At 29.9ppm S ββ The carbon peak (according to the nomenclature of "Monomer sequence distribution in ethylene-propylene rubber measured by 13C NMR. 3. Use of reaction probability models" 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 acquired using a 90° pulse with a 15 second delay between pulse and CPD to remove 1H-13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz.

[0097] Evaluation of spectral assignments, triplet distribution, and composition was performed according to Kakugo ("Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with δ-titanium trichloride-diethylaluminum chloride," M. Kakugo, Y. Naito, K. Mizunuma, and T. Miyatake, Macromolecules, 1982, 15, 1150) using the following equation:

[0098] PPP=100T ββ / S PPE=100T βδ / S EPE=100T δδ / S

[0099] PEP=100s ββ / S PEE=100S βδ / S EEE=100(0.25S γδ +0.5S δδ ) / S

[0100] S=T ββ +T βδ +T δδ +S ββ +Sβδ +0.25S γδ +0.5S δδ

[0101] The mole percentage of ethylene content was estimated using the following equation:

[0102] E% mol = 100 * [PEP + PEE + EEE] The weight percentage of ethylene content is estimated using the following equation:

[0103]

[0104] 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.

[0105] According to Carman (CJ Carman, RA Harrington and CE Wilkes, Macromolecules 1977; 10, 536), the product of the reaction ratios r1r2 is calculated as:

[0106]

[0107] The stereoregularity of the propylene sequence is determined by PPP mmT ββ (28.90-29.65ppm) and the entire T ββ The ratio of (29.80-28.37 ppm) was calculated as the mm content.

[0108] 1-Hexene and Ethylene Content:

[0109] Determination of 1-hexene content by NMR

[0110] Acquired on an AV-600 spectrometer operating at 150.91 MHz in Fourier transform mode at 120 °C 13 C NMR spectrum. The peak of propylene CH was used as an internal standard at 28.83. The following parameters were used to obtain 13 C NMR spectrum:

[0111] Spectral width (SW) 60ppm Spectral Center (O1) 30ppm Decoupling Sequence WALTZ 65_64pl Pulse Program ZGPG Pulse length (P1) For 90° Total Points (TD) 32K Relaxation delay 15s Number of transients 1500

[0112] The total amount of 1-hexene was calculated as a mole percent from the identified dyads present in the measured NMR using the following relationship:

[0113] [P]=PP+0.5PH

[0114] [H]=HH+0.5PH

[0115] Propylene / 1-hexene copolymer13 The assignments of C NMR spectra were calculated according to the following table:

[0116] 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 33.75 33.20 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 ]]> XEEE 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

[0117] Determination of ethylene and 1-hexene content by NMR

[0118] Acquired on an AV-600 spectrometer operating at 150.91 MHz in Fourier transform mode at 120 °C 13 C NMR spectrum. The peak of propylene CH was used as an internal standard at 28.83. The following parameters were used to obtain 13 C NMR spectrum:

[0119] Spectral width (SW) 60ppm Spectral Center (O1) 30ppm Decoupling Sequence WALTZ 16 Pulse Program ZGPG Pulse length (P1) For 90° Total Points (TD) 32K Relaxation delay 15s Number of transients 1500

[0120] The dyad distribution is calculated according to the following relationship:

[0121] PP=100I1 / Σ

[0122] PH=100I2 / Σ

[0123] HH=100I3 / Σ

[0124] PE=100I4 / Σ

[0125] EE=100(0.5(I12+I15)+0.25I11) / Σ

[0126] Where Σ=I1+I2+I3+I4+0.5(I12+I15)+0.25I11

[0127] The total amount (molar percent) of 1-hexene and ethylene was calculated from the dyads.

[0128] Use the following relationship:

[0129] [P]=PP+0.5PH+0.5PE

[0130] [H]=HH+0.5PH

[0131] [E]=EE+0.5PE

[0132] Propylene / 1-hexene / ethylene 13 Assignment of C NMR spectra

[0133] Copolymer

[0134]

[0135] The amount of 1-hexene in component b was calculated by using the following equation:

[0136] C6总 =C 6A *b+C 6B *b

[0137] Among them C 6总 is the amount of 1-hexene in the composition; C 6A is the amount of 1-hexene in component a); C 6B is the amount of 1-hexene in component b); and a and b are the amounts of components a) and b) such that a) + b) = 1.

[0138] By using formula C6 总 =C6 a xW a+ C6bxWb is the 1-hexene content of component b calculated from the total 1-hexene content of the composition, where C6 is the 1-hexene content, Wa and Wb are the amounts of components a and b.

[0139] Ethylene content in 1-butene-ethylene copolymer

[0140] The comonomer content was determined by infrared spectroscopy using a Fourier transform infrared spectrometer (FTIR) to collect infrared spectra of the sample relative to an air background. The instrument data acquisition parameters were:

[0141] Purge time: at least 30 seconds

[0142] Collection time: at least 3 minutes

[0143] Apodization method: Happ-Genzel

[0144] Resolution: 2cm -1 .

[0145] Sample Preparation - Using a hydraulic press, a thick sheet was obtained by compression molding about 1 g of sample between two aluminum foils. A small portion was cut from the sheet to mold a thin film. The film thickness was set to have a 1.3 au at ~720 cm -1 The maximum absorbance of the CH2 absorption band was recorded at 180 ± 10 °C (356 °F) and the pressure was about 10 kg / cm 2 (142.2 PSI) for about 1 minute. The pressure was then released and the sample was removed from the press and allowed to cool to room temperature. The spectra of the pressed samples were plotted as absorbance versus wave number (cm -1 The following measurements were used to calculate the ethylene (C2) and 1-butene (C4) contents:

[0146] a) at 4482-3950cm -1 The area of ​​the combined absorption band (A t ), used for spectral normalization of film thickness.

[0147] b) After appropriate digital subtraction of the isotactic polypropylene (IPP) and C2C4 reference spectra, the -1 The area of ​​the absorption band caused by the methylene sequence (CH2 rocking vibration) in the range (A C2 ).

[0148] c) Subtraction factor (FCR) between the spectrum of the polymer sample and the C2C4 reference spectrum C4 ) Reference spectra were obtained by linear polyethylene digital subtraction of C2C4 copolymers to extract the C4 band (ethyl at ∼771 cm-1).

[0149] Scale A C2 / A t Calibration was performed by analyzing ethylene-1-butene standard copolymers of known composition, determined by NMR spectroscopy. To calculate the ethylene (C2) and 1-butene (C4) contents, the ethylene (C2) and 1-butene (C4) contents were calculated by using 13 C NMR was used to obtain a calibration curve using samples of known amounts of ethylene and 1-butene.

[0150] Calibrate vinyl - by drawing A C2 / A t The calibration curve was obtained relative to the molar percentage of ethylene (% C2m), and the coefficient a was then calculated by "linear regression" C2 、b C2 and c C2 .

[0151] Calibrate 1-butene - by plotting the FCR C4 / A t The relationship between the molar percentage of butane (% C4m) and the coefficient a was calculated by linear regression. C4 、b C4 and C C4 .

[0152] Record the spectrum of the unknown sample and then calculate the unknown sample (A t )、(A C2 ) and (FCR C4 ).

[0153] The ethylene content (% mole fraction C2m) of the sample was calculated as follows:

[0154]

[0155] The 1-butene content (% mole fraction C4m) of the sample was calculated as follows:

[0156]

[0157] a C4 、bC4 、c C4 、a C2 、b C2 、c C2 are the two calibration coefficients.

[0158] The change from mol% to wt% was calculated by using the molecular weight.

[0159] Tensile modulus was measured according to ISO 527-2 and ISO 1873-2 on injection molded specimens.

[0160] Flexural modulus is measured according to ISO 178 with additional conditions according to ISO 1873-2 on injection molded specimens.

[0161] Seal Initiation Temperature (SIT)

[0162] Preparation of membrane samples

[0163] Films with a thickness of 50 μm were prepared by extruding each test composition in a single screw Collin extruder (screw length / diameter ratio 1:25) at a film drawing speed of 7 m / min and a melt temperature of 210-250°C.

[0164] Each of the resulting films was superimposed on a 1000 μm thick film of a propylene homopolymer having a xylene insoluble fraction at 25° C. of 97 wt% and an MFR L of 2 g / 10 min.

[0165] The superimposed films were bonded to each other in a Carver press at 200° C. under a load of 9000 kg, which was maintained for 5 minutes.

[0166] The resulting laminate was stretched 6 times in the longitudinal and transverse directions (ie, biaxially) at 160° C. using a Karo 4 Brueckener film stretcher, thereby obtaining a 20 μm thick film (18 μm homopolymer+2 μm test).

[0167] Determination of SIT.

[0168] A 6 cm wide and 35 cm long strip of film was cut from the center of the BOPP film and superimposed with a BOPP film made from a 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 approximately 10°C lower than the melting temperature of the test composition. The sealing strip was cut into six 15 mm wide specimens, long enough to be protected in the tensile tester fixture. The seal strength was tested using a 12FE7234-EP-P1 load cell with a capacity of 100 N, a transverse speed of 100 mm / min, and a clamping distance of 50 mm. The results are expressed as the average value of the maximum seal strength (N). The films were cooled and then their unsealed ends were attached to an Instron machine, where they were tested at a pulling speed of 50 mm / min.

[0169] The test was then repeated by varying the temperature as follows:

[0170] If the seal strength is 1.5 N, then reduce the temperature. If the seal strength is close to the target select a step of 1°C, if the strength is away from the target select a step of 2°C, then the temperature change must be adjusted stepwise.

[0171] 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.

[0172] Determination of hot viscosity

[0173] Hot tack measurement after sealing by a Brugger HSG heat sealer (with a hot tack test kit). Samples obtained from BOPP film need to be cut with a minimum length of 200 mm and a width of 15 mm and tested under the following conditions:

[0174] The temperature was set from no seal to 130°C in steps of 5°C; at each temperature, the weight required to rupture the film near the seal was set.

[0175] The specimen was considered broken when 50% or more of the sealed portion was open after impact.

[0176] Preparation of copolymer component A

[0177] Catalyst system

[0178] Procedure for the preparation of spherical adducts

[0179] Microspherical MgCl2.pC2H5OH adduct was prepared according to the method described in Comparative Example 5 of WO98 / 44009, except that 3 mol% of BiCl3 in powder form relative to the amount of magnesium was added before the oil feed.

[0180] Procedure for preparing solid catalyst components

[0181] Under a nitrogen atmosphere, 300 ml of TiCl₄ was introduced into a 500 ml round-bottom flask equipped with a mechanical stirrer, a cooler, and a thermometer at room temperature. After cooling to 0°C, 9.0 g of the spherical adduct (prepared as described above) was added with stirring, followed by the addition of diethyl 3,3-dipropylglutarate to the flask. The amount of internal donor added was such that the Mg / donor molar ratio was 13. The temperature was raised to 100°C and maintained for 2 hours. Thereafter, stirring was stopped, the solid product was allowed to settle, and the supernatant was siphoned off at 100°C.

[0182] After siphoning, fresh TiCl4 and an amount of 9,9-bis(methoxymethyl)fluorene were added to produce a Mg / diether molar ratio of 13. The mixture was then heated to 120°C and maintained at this temperature with stirring for 1 hour. Stirring was again stopped, the solid was allowed to settle, and the supernatant was siphoned off. The solid was washed six times with anhydrous hexane in a temperature gradient down to 60°C and once at room temperature. The resulting solid was then dried under vacuum and analyzed.

[0183] Catalyst system and prepolymerization treatment

[0184] Before being introduced into the polymerization reactor, the above solid catalyst component was brought into contact with triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) as external donors at 15°C for about 6 minutes.

[0185] The catalyst system was then prepolymerized by keeping it in suspension in liquid propylene at 20°C for about 20 minutes before being introduced into the polymerization reactor.

[0186] polymerization

[0187] A copolymer of propylene and 1-hexene (component (a)) is prepared by feeding a prepolymerized catalyst system, hydrogen (used as a molecular weight regulator), gaseous propylene and 1-hexene into a first gas phase polymerization reactor in a continuous and constant flow. The polypropylene copolymer prepared in the first reactor is discharged in a continuous flow and introduced into a second gas phase polymerization reactor in a continuous flow together with a quantitative and constant flow of gaseous hydrogen, 1-hexene and propylene.

[0188] The polypropylene copolymer produced in the second reactor is discharged as a continuous flow and, after purging of unreacted monomers, introduced as a continuous flow into the third gas phase polymerization reactor together with a gaseous quantitative constant flow of hydrogen, 1-hexene and propylene.

[0189] The polymerization conditions are reported in Table 1.

[0190] Table 1

[0191] Example 1 Catalyst feed g / h 14.3 TEAL / solid catalyst component weight ratio g / g 4 TEAL / D donor weight ratio g / g 10 Prepolymerization temperature 20 Dwell time 34 First gas phase reactor Polymerization temperature ℃ 75 MFR g / 10min 5.4 pressure -bar 15 H2 / C3 mol / mol 0.0035 C6 / C6+C3 mol / mol 0.135 Splitting first reactor (amount A) wt% 24 Second gas phase reactor Polymerization temperature ℃ 75 pressure -bar 15 MFR* g / 10min 6.1 H2 / C3 mol / mol 0.035 C6 / C6+C3 mol / mol 0.194 Split second reactor (amount B) wt% 26 The third gas phase reactor Polymerization temperature ℃ 65 pressure -bar 14 MFR* g / 10min 6.2 H2 / C3 mol / mol 0.051 C2 / C2+C3 mol / mol 0.032 Split third reactor (amount C) wt% 50

[0192] C3 = propylene; C6 = 1-hexene; C2 = ethylene; H2 = hydrogen

[0193] The polymer obtained according to Table 1 has been added with 0.05% Irg.1010; then 0.1% Irg.168 and 0.05% CaSt are pelletized. The characteristics of the composition are reported in Table 2

[0194] Table 2

[0195]

[0196] C3 = propylene; C6 = 1-hexene; C2 = ethylene;

[0197] **Calculated by using the formula logMFRtotal = XalogMFRa + XblogMFRb;

[0198] *Calculated by using the formula Ytotal = XaYa + XbYb, where Y is the comonomer content and Xa and Xb are the split (Xa + Xb = 1).

[0199] It is calculated by using the general formula XStotal=XaXsa+XbXsb, where X is the total xylene soluble content, Xsa and Xsb are the fractional xylene soluble content, and Xa and Xb are the split (Xa+Xb=1).

[0200] Component B

[0201] Component B is a commercial product sold by LyondelBasell under the trade name Koattro DP 8310M.

[0202] The characteristics of Component B are reported in Table 3.

[0203] Table 3

[0204] Component B MFR 190℃2.16kg g / 10min 3.5 flexural modulus MPa 120 Tm ℃ 94 Ethylene content Wt% 3.7

[0205] Various amounts of component B were blended with component A. For each blend, two layers of BOPP film were produced. The two layers were made from the same components. The seal initiation temperature was measured. Table 4 reports the SIT for each sample.

[0206] Table 4

[0207] Example Component B SIT℃ Component 1 0 87 2 10wt% 68 3 15wt% 65 4 20wt% 63

[0208] Hot tack

[0209] The hot tack of the films of Comparative Example 1 and Examples 2-4 was measured at various temperatures. The results are reported in Table 5.

[0210] Table 5

[0211] Temperature Comparative Example 1 Example 2 Example 3 Example 4 Hot viscosity g Hot viscosity g Hot viscosity g Hot viscosity g 80 108 198 238 413 90 181 163 283 288 110 358 93 343 693 120 268 200 693 400

[0212] Table 4 shows that the compositions according to the invention exhibit a lower SIT compared to component A alone. The improvement in the hot tack values ​​is also clearly evident in Table 5.

[0213] Comparative Example 5

[0214] Comparative component B1 is a 1-butene-ethylene copolymer sold by Lyondellbasell under the trade name Toppyl PB 8220M. The characteristics of this polymer are reported in Table 6.

[0215] Table 6

[0216] Component B1 MFR 190℃2.16kg g / 10min 2.5 flexural modulus MPa 140 Tm ℃ 97 Ethylene content Wt% 2.7

[0217] 20 wt% of Component B1 was blended with 80 wt% of Component A. Two layers of BOPP film were produced for each blend. Both layers were made from the same components. The seal initiation temperature was measured at 65°C, while the SIT result for the composition of Example 4 was 63°C. Comparative Example 5 exhibited good hot tack measurements. Table 7 reports the hot tack values ​​compared to those of Example 4.

[0218] Table 7

[0219] Temperature Example 4 Comparative Example 5 Hot viscosity g Hot viscosity g 80 413 288 90 288 273 100 288 238 110 693 331

[0220] Table 7 shows that the composition of Example 5 has higher hot tack relative to the comparative example.

Claims

1. A polymer composition comprising: A) 70 wt% to 95 wt% of a propylene-based composition comprising: a) 15 to 35 wt% of a copolymer of propylene and 1-hexene, which contains 6.2 to 8.5 wt% of 1-hexene-derived units and has a melt flow rate MFR of 3.5 to 8.5 g / 10 min, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg; b) 15 to 35 wt% of a copolymer of propylene and 1-hexene, containing 10.4 to 14.5 wt% of 1-hexene-derived units and having a melt flow rate MFR of 3.5 to 8.5 g / 10 min, measured according to ASTM D 1238-13, 230° C. / 2.16 kg, i.e. at 230° C. under a load of 2.16 kg; c) 38 to 68 wt% of a copolymer of propylene and ethylene containing 3.4 to 5.7 wt% of ethylene-derived units, having a melt flow rate MFR of 3.5 to 12.0 g / 10 min, measured according to ASTM D 1238-13, 230°C / 2.16 kg, i.e. at 230°C under a load of 2.16 kg, and a xylene solubles content at 25°C of 3.7 to 7.8 wt%; The sum of the amounts of components a), b) and c) in the propylene-based composition is 100 wt%; in: i) the total amount of 1-hexene-derived units in components a) and b) is from 9.4 wt% to 11.6 wt%; ii) the propylene-based composition has a xylene solubles content at 25° C. of 14.2 wt % to 19.3 wt %; iii) the propylene-based composition has a 1-hexene content of 3.7 wt% to 6.4 wt%; iv) the propylene-based composition has a melting temperature of 128°C to 135°C, as measured by DSC, B) a copolymer of 13 to 30 wt% of 1-butene and ethylene, containing 3.0 to 4.2 wt% of ethylene-derived units, having a melt flow rate in the range of 1.0 to 5.5 g / 10 min, measured according to ISO 1133-1 at 190°C, 2.16 kg, a flexural modulus in the range of 80 to 250 MPa, measured according to ISO 178, and a melting temperature in the range of 83 to 108°C, measured according to ISO 11357-2013, Form I; The sum of the amounts of A) and B) in the polymer composition is 100 wt%.

2. The polymer composition of claim 1, wherein component A) ranges from 74 wt% to 87 wt%; and component B) ranges from 13 wt% to 26 wt%.

3. The polymer composition of claim 1, wherein component B) contains 3.2 to 4.0 wt% of ethylene-derived units.

4. The polymer composition according to claim 1, wherein in component B), the melt flow rate is in the range of 2.1 to 4.8 g / 10 min as measured according to ISO 1133-1 - 190°C, 2.16 Kg. 5 . The polymer composition according to claim 1 , wherein component B) has a melting temperature in the range of 84° C. to 103° C. measured according to ISO 11357-2013, Form I.

6. The polymer composition of claim 1, wherein component a) ranges from 20 wt% to 31 wt%; component b) ranges from 20 wt% to 31 wt%; and component c) ranges from 42 wt% to 62 wt%.

7. The polymer composition of claim 1, wherein component a) contains 6.8 to 8.1 wt% of 1-hexene-derived units.

8. The polymer composition of claim 1, wherein component b) contains 11.2 wt% to 13.9 wt% of 1-hexene-derived units.

9. The polymer composition of claim 1, wherein component c) contains 3.9 wt% to 5.1 wt% of ethylene-derived units.

10. The polymer composition according to claim 1, wherein the sum of components a) + b) has a 1-hexene-derived unit content in the xylene-soluble fraction at 25°C of 18.0 wt% to 32.0 wt%.

11. The polymer composition according to claim 1, wherein in component A), the xylene soluble content at 25°C is 15.3 wt% to 18.7 wt%.

12. The polymer composition according to claim 1, wherein the content of 1-hexene-derived units in A) is from 3.9 wt% to 5.4 wt%.

13. The polymer composition of claim 1, wherein component c) has an ethylene-derived unit content of 10.0 wt% to 17.0 wt% in the xylene-soluble fraction at 25°C.

14. A film comprising the polymer composition according to claim 1.

15. A multilayer film comprising the polymer composition of claim 1.

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