Propylene terpolymer

Abstract

A terpolymer compositions comprising: A) ) From 65 wt% to 95 wt%; of a propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 1.1 wt% to 4.3 wt%; ii) the content of 1-butene derived units ranging from 2.2 wt% to 5.7 wt%; B) from 5 wt% to 35 wt%; of a propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 3.3 wt% to 6.8 wt%; ii) the content of 1-butene derived units ranging from 7.7 wt% to 13.2 wt%;

Description

TITLEPROPYLENE TERPOLYMERFIELD OF THE INVENTION

[0001] The present disclosure relates to a composition comprising terpolymer of propylene ethylene and 1 -butene having a low seal initiation temperature and good optical properties suitable for obtaining films, in particular biaxially oriented polypropylene films (BOPP) and cast films having a reduced number of gels.BACKGROUND OF THE INVENTION

[0002] It is well known that propylene, ethylene and 1 -butene terpolymers can be used for obtaining films, in particular biaxially oriented polypropylene films (BOPP) widely used for the packaging of foodstuff using automatic machines. In fact the said films are characterized by a particular good balance of processability (“machinability”), optical and mechanical properties.

[0003] WO 2024 / 061958 relates to a propylene / ethylene / 1 -butene terpolymer composition comprising two terpolymers. In particular the composition has a content of 2,1 regiodefects in the range from 0.1 to 1.0 mol% and a a xylene cold soluble content (XCS) in the range from 0 to 3.0 wt.-%, as determined according to ISO 16152.

[0004] WO 2023 / 046824 relates to a monophasic propylene / ethylene / 1 -butene terpolymer composition comprising two terpolymers. In particular the composition has a content of 2,1 regiodefects in the range from 0.1 to 1.0 mol% and a xylene cold soluble content (XCS) in the range from 1.00 to 3.00 wt.-%, as determined according to ISO 16152.

[0005] The applicant found that it is possible to obtain an composition comprising terpolymer of propylene ethylene and 1 -butene having low sealing initiation temperature and good optical properties fit for producing films, in particular biaxially oriented polypropylene films (BOPP) and cast films having a reduced number of gels by finely tuning a composition comprising two propylene / ethylene / 1 -butene terpolymersSUMMARY OF THE INVENTION

[0006] Thus, the present disclosure provides a terpolymer compositions comprising:A) From 65 wt% to 95 wt%; preferably from 68 wt% to 92 wt%; more preferably from 72 wt% to 88 wt% of a propylene, ethylene, 1 -butene terpolymer having:i) the content of ethylene derived units ranging from 1.1 wt% to 4.3 wt%; preferably ranging from 1.3 wt% to 3.8 wt%; more preferably ranging from 1.5 wt% to 3.1 wt%;ii) the content of 1 -butene derived units ranging from 2.2 wt% to 7.0 wt%; preferably from 2.2 wt% to 5.7 wt%; more preferably ranging from 2.7 wt% to 5.4 wt%; even more preferably ranging from 3.2 wt% to 5.2 wt%;iii) the xylene soluble fraction at 25°C, as determined according to ASTM D 5492, ranging from 5.5 wt% to 15.5 wt%; preferably from 6.5 wt% to 15.5 wt%; more preferably ranging from 8.7 wt% to 13.5 wt%; even more preferably ranging from 9.2 wt% to 12.2 wt%;B) from 5 wt% to 35 wt%; preferably from 8 wt% to 32 wt%; more preferably from 12 wt% to 28 wt% of a propylene, ethylene, 1 -butene terpolymer having:i) the content of ethylene derived units ranging from 3.3 wt% to 6.8 wt%; preferably ranging from 3.7 wt% to 6.3 wt%; more preferably ranging from 4.0 wt% to 5.6 wt%;ii) the content of 1 -butene derived units ranging from 7.7 wt% to 15.0 wt%;preferably from 7.7 wt% to 13.2 wt%; more preferably ranging from 8.2 wt% to 12.7 wt%;even more preferably ranging from 9.3 wt% to 11.8 wt%;iii) the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranging from 11.3 wt% to 32.4 wt%; preferably ranging from 14.4 wt% to 30.3 wt%; more preferably ranging from 18.1 wt% to 27.2 wt%;the sum of the amounts of A) and B) being 100 wt%;the terpolymer composition having:i) the melt flow rate, MFR, measured according to ISO 1133 at 230 °C with a load of 2.16 kg, ranging from 3.4 g / 10 min to 12.9 g / 10 min; preferably ranging from 4.4 g / 10 min to 10.9 g / 10 min; more preferably ranging from 5.4 g / 10 min to 8.9 g / 10 min;ii) the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranging from 8.0 wt% to 23.2 wt%; preferably 12.7 wt% to 23.2 wt%; more preferably ranging from 14.7 wt% to 21.7 wt%; even more preferably ranging from 15.4 wt% to 19.7 wt%;iii) the melting point determined by differential scanning calorimetry (DSC), according to ISO 11357-3, with a heating rate of 20 °C / minute ranging from 120°C to 138 °C; preferably ranging from 125°C to 135 °C; more preferably ranging from 127°C to 133 °C;vi) the 2,1 regiodefects cannot be detected at 13CNMR with the method reported in the examples.DETAILED DESCRIPTION OF THE INVENTION

[0007] The term "copolymer" as used in the present disclosure refers to polymers containing only two comonomers such as propylene and ethylene or 1 -butene and ethylene, the term propylene ethylene 1 -butene terpolymer is defined as containing only propylene, ethylene and 1-butene comonomers. .Preferably in the terpolymer composition of the present disclosure:iv) the content of ethylene derived units ranges from 1.5 wt% to 5.3 wt%; preferably ranges from 1.7 wt% to 4.8 wt%; more preferably ranges from 2.2 wt% to 4.4 wt%; and / orv) the content of 1 -butene derived units ranges from 5.2 wt% to 9.5 wt%; preferably ranges from 5.7 wt% to 8.5 wt%; more preferably ranges from 6.3 wt% to 8.2 wt%

[0008] The terpolymer composition of the present disclosure can be added with polybutene in order to further lower the sit and to lower the gel counts on the films, in particular cast films.

[0009] A further object of the present disclosure is a polyolefin composition comprising:

[0010] Tl) from 85 wt% to 99 wt%; preferably from 90 wt% to 98 wt%; even more preferably from 92 wt% to 97.5 wt% of the terpolymer composition disclosed above;

[0011] T2) from 1.0 wt% to 15.0 wt%; preferably from 2.0 wt% to 10.0 wt%; more preferably from 2.5 wt% to 8 wt% of a copolymer of 1 -butene and ethylene containing from 2.5 wt% to 4.8 wt% preferably from 2.8. wt% to 4.5 wt%; more preferably from 3.4 wt% to 4.3. wt% of ethylene derived units; said copolymer of 1 -butene and ethylene having:

[0012] - a Melt Flow Rate: measured according to ISO 1133-1 -(190 °C, 2.16Kg) ranging from 30.0 to 60.0 g / 10 min preferably from 35.0 to 55.0 g / 10 min; more preferably from 32.0 to 51.0 g / 10 min;

[0013] the xylene soluble fraction at 0°C, measured according to the method of the examples , ranging from 44 wt% to 68 wt%; preferably ranging from 47 wt% to 65 wt%; more preferably ranging from 50 wt% to 61 wt%;

[0014] The melting temperature measured according to Iso 11357-3 ranging from 83°C and 108 °C, preferably ranging from 84°C and 103 °C; more preferably ranging from 88°C and 100 °C, form I;

[0015] The polyolefin composition of the present disclosure is preferably endowed with one or more of the following properties:a) Number of gels measured on 50p cast film having a diameter higher than 0.2 mm ranging from 10 to 70; preferably ranging from 20 to 55; more preferably ranging from 25 to 45 b) e) Number of gels measured on 50p cast film having a diameter higher than 0.1 mm ranging from 100 to 400; preferably ranging from 110 to 350; more preferably ranging from 120 to 300.

[0016] Component A) of the terpolymer composition of the present disclosure is preferably characterized by a xylene soluble fraction measured at 0°C and 25°C with the method reported in the examples ranging from 3.0 wt% to 6.8 wt%; preferably ranging from 3.5 wt% to 6.4 wt%; more preferably ranging from 4.0 wt% to 6.1 wt%.

[0017] Component B) of the terpolymer composition of the present disclosure is preferably characterized by a xylene soluble fraction measured at 0°C and 25°C with the method reported in the examples ranging from 9.5 wt% to 27.5 wt%; preferably ranging from 12.5 wt% to 25.4 wt%; more preferably ranging from 14.4 wt% to 22.5 wt%.

[0018] The terpolymer composition of the present disclosure is preferably heterophasic.

[0019] The terpolymer composition of the present disclosure is preferably endowed with one or more of the following properties:a) Seal initiation temperature (SIT) measured according to the method reported in the examples on BOPP film, fulfilling the following inequation:Tm-SIT>18.0°C; preferably Tm-SIT>19.0°C;b)= Gloss at 45° measured according to on 50p cast film ranging from 80 and 100; preferably form 83 and 95; more preferably from 85 and 92;c) Haze measured according to — on ma 50p cast film ranging from 0.10 % to 0.35 %; preferably from 0.15% to 0.30; more preferably from 0.16 to 0.22 %.Component T2) is a 1 -butene ethylene copolymer commercially available, such as Koattro DP 8310M or il PB8510M sold by LyondellBasell and can be prepared according to processes known in the art by using Ziegler Natta catalysts.

[0020] The polyolefin composition of the present disclosure can be prepared by mechanically blending component Tl) and component T2) in accordance with processes well known in the art.

[0021] The process for preparing the terpolymer compositions of the present disclosure is carried out in presence of a highly stereospecific heterogeneous Ziegler-Natta catalyst. TheZiegler-Natta catalysts comprise a solid catalyst component comprising at least one titanium compound having at least one titanium-halogen bond and at least an electron-donor compound (internal donor), both supported on magnesium chloride. The Ziegler-Natta catalysts systems further comprise an organo-aluminum compound as essential co-catalyst and optionally an external electron-donor compound.

[0022] Suitable catalysts systems are described in the European patents EP45977, EP361494, EP728769, EP 1272533 and in the international patent application W000163261.

[0023] The terpolymer compositions of the present disclosure are preferably prepared in a cascade process wherein component A) is prepared in a slurry reactor and then component B) is prepared in a gas phase reactor in the presence of component A) without the need to add additional catalyst.

[0024] The terpolymer compositions and the polyolefin compositions of the present disclosure are particularly fit for the production of films, in particular cast or BOPP films.

[0025] The film obtained with the terpolymer composition and the polyolefin compositions of the present disclosure may also contain the additives that are commonly used for the film manufacturing, and especially for the films used for packaging applications with automatic machines, such as anti-oxidants, process stabilizers, slip agents, antistatic agents, antiblock agents, and antifog agents.

[0026] The following examples are given to illustrate, not to limit, the present disclosure:EXAMPLESXylene-soluble (XS) Fraction at 25 °C

[0027] Xylene Solubles at 25°C have been determined according to ISO 16152: 2005.Xylene-soluble (XS) Fraction at 0°C / 25 °C

[0028] 2.5 g of copolymer and 250 cm3of o-xylene are placed in a glass flask fitted with a condenser and a magnetic stirrer. The temperature is increased to the boiling point of the solvent over 30 min. The clear solution thus formed is left at reflux with stirring fora further 30 min. The closed flask is then placed in a bath of ice- water for 30 min and then in a bath of water thermostatically adjusted to 25° C. for 30 min. The solid formed is then filtered off on filter paper at a high filtration rate. 100 cm3of the liquid obtained from the filtration are poured into a preweighed aluminium container, which is placed on a hot-plate to evaporate off the liquid under a stream of nitrogen. The container is then placed in an oven at 80° C. and maintained under vacuum45 until a constant weight is obtained. From the amount of filtrate, the amount of polymer soluble in xylene is calculated.Seal Initiation Temperature

[0029] Preparation of the film specimens

[0030] Some films with a thickness of 50 pm are prepared by extruding each test composition in a single screw Collin extruder (length / diameter ratio of screw 1 :25) at a film drawing speed of 7 m / min and a melt temperature do 210-250 °C.

[0031] Each resulting film is superimposed on a 1000 pm thick film of a propylene homopolymer having a xylene insoluble fraction at 25°C of 97 wt% and a MFR L of 2 g / 10 min.

[0032] The superimposed films are bonded to each other in a Carver press at 200°C under a 9000 kg load, which is maintained for 5 minutes.

[0033] The resulting laminates are stretched longitudinally and transversally, i.e. biaxially, by a factor 6 with a Karo 4 Brueckener film stretcher at 160°C, thus obtaining a 20 pm thick film (18 pm homopolymer+2 pm test).Determination of the SIT

[0034] Film Strips, 6 cm wide and 35 cm length are cut from the center of the BOPP film he film was superimposed with a BOPP film made of PP homopolymer. The superimposed specimens are sealed along one of the 2 cm sides with a Brugger Feinmechanik Sealer, model HSG-ETK 745. Sealing time is 5 seconds at a pressure of 0.14 MPa (20 psi). The starting sealing temperature is from about 10 °C less than the melting temperature of the test composition. The sealed strip is cut in 6 specimens 15 mm wide long enough to be claimed in the tensile tester grips. The seal strength is tested and load cell capacity 100 N, cross speed 100 mm / min and grip distance 50 mm. The seal strength is measured as the average value of 6 specimens.

[0035] The test is than repeated by changing the temperature as follows:

[0036] If seal strength 1.5 N then decrease the temperature. Temperature variation must be adjusted stepwise, if seal strength is close to target select steps of 1°C if the strength is far from target select steps of 2°C.

[0037] The target seal strength (SIT ) is defined as the lowest temperature at which a seal strength higher or equal to 1.5 N is achieved.Melting temperature (ISO 11357-2013)

[0038] The melting temperature Tml is the melting temperature attributable to the crystalline form I of the copolymer. In order to determine the Tml, the copolymer sample is melted and then cooled down to 20°C with a cooling rate of 10°C / min., kept for 10 days at room temperature, and then subjected to differential scanning calorimetry (DSC) analysis by cooling to -20°C and then heating to 200°C with a scanning speed corresponding to 10°C / min. In this heating run, the peak in the thermogram is taken as the melting temperature (Tml).Melt Flow Rate (MFR)

[0039] Measured according to ISO 1133 at 230 °C with a load of 2.16 kg, unless otherwise specified.Determination of the Haze

[0040] 50pm cast films has ben used. The haze value is measured using a Gardner photometric unit connected to a Hazemeter type UX-10 or an equivalent instrument having G.E. 1209 light source with filter "C". Reference samples of known haze are used for calibrating the instrument according to ASTM DI 003.Determination of Ethylene and 1-butene content

[0041] 13C NMR spectra were acquired on a Bruker AV600 spectrometer equipped with cryo probe, operating 150.91 MHz MHz in the Fourier transform mode at 120 °C.

[0042] The peak of the Sgg carbon (nomenclature according C.J. Carman, R.A. Harrington and C.E. Wilkes, Macromolecules, 10, 3, 536 (1977)) was used as internal reference at 29.9 ppm. About 30 mg of sample were dissolved in 0.5 ml of 1,1, 2, 2 tetrachloro ethane d2 at 120 °C w. Each spectrum was acquired with a 90 ° pulse, 15 seconds of delay between pulses and CPD to removeJH-13C coupling. 512 transients were stored in 65 K data points using a spectral window of 9000 Hz.

[0043] Triad distribution was obtained using the following relations:XPX= 100 I8 / SXPE = 100 I5 / SEPE = 100 I4 / SXBX= 10013 / SXBE =10012 / SXEX=100 I9 / SXEE =100 Ii / SEEE = 100 (0.5 I7 + 0.25 I6) / SWhere 2 — Is+ Is + I4+I3 + I2+I9 + Ii+ 0.5 I7 + 0.25 IsI are the areas of the corresponding carbon as reported in Table aand X can be propylene or 1 -butene

[0044] The molar content of Ethylene, Propylene and 1 -Butene is obtained from triads using the following relations:P (m%) = XPX + XPE + EPEB (m%) = XBX + XBE+ EBEE (m%) = EEE + XEE + XEXMolar content was transformed in weight using monomers molecular weight.Table A: Assignments of the13C NMR spectrum of Ethylene / Propylene / l-Butene terpolymersThe presence of isolated 2, 1 -erythro regio defects was indicated by the presence of the two methyl sites at 17. 7 and 17.2 ppm, by the methylene site at 42.4 ppm and confirmed by other characteristic sites. Tue presence of 2, 1 regio defect adjacent an ethylene unit was indicated by the two inequivalent SaP signals at 34.8 ppm and 34.4 ppm respectively and the TYY at 33.7 ppm.The gels count testThe gels count test has been carried out on a cast film Collin Extrusion line diameter with a 25 mm single screw with the following features:Single screw L / D 25Temperature profileCylinders 200 (close to the hopper) -> 230°C (at the end of the extruder, before the inlet to the die) Die 240°CDie width 150 mmChill roll 30°CFilm speed 3.0 m / minFilm thickness 50 micronInspected area 1 m2CS FS5 gel count unit on a 4 cm wide stripeGloss:Measured on ASTM D2457 (angle 45°) on 50pm cast filmsExample 1

[0045] The solid catalyst used in the following example was prepared according to the Example 1 of the European Patent EP728769. Triethylaluminium (TEA1) was used as co-catalyst and dicyclopentyldimethoxysilane as external donor, with the weight ratios indicated in Table 1 together with the polymerization conditions.

[0046] Then the resulting mixture is subjected to prepolymerization by maintaining it in suspension in liquid propylene at 20 °C for about 5 minutes before introducing it into the polymerization reactor.Polymerization

[0047] The polymerization run is carried out in continuous mode in a series of two reactors equipped with devices to transfer the product from one reactor to the one immediately next to it. The first reactor is liquid phase loop reactors and the second reactor is a second fluidized bed gas phase polymerization reactor. Propylene is the main solvent, hydrogen is used as molecular weight regulator. The gas phase is continuously analyzed via gaschromatography.

[0048] [The polymer produced in the first reactor is discharged in a continuous flow and it is introduced, in a continuous flow, into a second fluidized bed gas phase polymerization reactor, together with quantitatively constant flows of hydrogen (when used ) 1 -butene, ethylene and propylene in the gas state as reported in table 1. Samples of the terpolymer of the first reactors aretaken in order to test and analyze them. The polymer particles exiting from the polymerization step were subjected to a steam treatment to remove the unreacted monomers and dried under a nitrogen flow.

[0049] The main precontact, prepolymerization and polymerization conditions and the quantities of monomers and hydrogen fed to the polymerization reactor are reported in Table 1.

[0050] The properties of the polymers are reported on example 2.Table 1C2 = ethylene; C3 = propylene : C4 = 1 -buteneTable 2> >* calculated** the composition has been visbrooken to MFR 6.0

[0051] Comparative example 2 is a commercial terpolymer sold by Lyondellbasell. Table 2 shows that example 1 shows a better SIT gloss and Haze with respect to comparative example 2.

[0052] Component T2 is a commercial 1-butene / ethylene copolymer sold by Lyondelbasell

[0053] The features of component B are reported on table 3.Table 3The terpolymer of example 1 (component Tl) has been blended with 3 wt% and 5 wt% of component T2. The characterizations is reported on table 4Table 4>>The addition of component T2 improve the gel count on cast film.

Claims

CLAIMSWhat is claimed is:

1. A terpolymer compositions comprising:A) ) From 65 wt% to 95 wt%; of a propylene, ethylene, 1 -butene terpolymer having: i) the content of ethylene derived units ranging from 1.1 wt% to 4.3 wt%;ii) the content of 1 -butene derived units ranging from 2.2 wt% to 7.0 wt%; iii) the xylene soluble fraction at 25°C, as determined according to ASTM D 5492, ranging from 5.5 wt% to 15.5 wt%;B) from 5 wt% to 35 wt%; of a propylene, ethylene, 1-butene terpolymer having:i) the content of ethylene derived units ranging from 3.3 wt% to 6.8 wt%;ii) the content of 1-butene derived units ranging from 7.7 wt% to 15.0 wt%; iii) the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranging from 11.3 wt% to 32.4 wt%;the sum of the amounts of A) and B) being 100 wt%;the terpolymer composition having:i) the melt flow rate, MFR, measured according to ISO 1133 at 230 °C with a load of 2.16 kg, ranging from 3.4 g / 10 min to 12.9 g / 10 min;ii) the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranging from 8.0 wt% to 23.2 wt%;iii) the melting point determined by differential scanning calorimetry (DSC), according to ISO 11357-3, with a heating rate of 20 °C / minute ranging from 120°C to 138 °C;iv) the content of ethylene derived units ranging from 1.5 wt% to 5.3 wt%;v) the content of 1-butene derived units ranging from 5.2 wt% to 9.5 wt%;vi) the 2,1 regiodefects cannot be detected at13CNMR with the method reported in the examples.

2. The terpolymer according to claim 1 comprising from 68 wt% to 92 wt% of component A) and from 8 wt% to 32 wt% of component B).

3. The terpolymer according to anyone of claims 1-2 wherein in component A) the xylene soluble fraction at 25 °C ranges from 6.5 wt% to 15.5 wt%.

4. The terpolymer according to anyone of claims 1 -3 wherein in component A) the content of ethylene derived units ranges from 1.3 wt% to 3.8 wt%.

5. The terpolymer according to anyone of claims 1-4 wherein in component A) the content of 1 -butene derived units ranges from 2.2 wt% to 5.7 wt%.

6. The terpolymer according to anyone of claims 1-5 wherein in component A) the content of ethylene derived units ranges from 0.7 wt% to 2.8 wt%.

7. The terpolymer according to anyone of claims 1 -6 wherein in component B) the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranges from 14.4 wt% to 30.3 wt%.

8. The terpolymer according to anyone of claims 1-7 wherein in component B) the content of ethylene derived units ranges from 3.7 wt% to 6.3 wt%.

9. The terpolymer according to anyone of claims 1-8 wherein in component B) the content of 1 -butene derived units ranges from 7.7 wt% to 13.2 wt%.

10. The terpolymer according to anyone of claims 1-9 having the melt flow rate, MFR, measured according to ISO 1133 at 230 °C with a load of 2.16 kg, ranging from 4.4 g / 10 min to 10.9 g / 10 min.

11. The terpolymer according to anyone of claims 1-10 wherein the xylene soluble fraction at 25°C as determined according to ASTM D 5492, ranges from 12.7 wt% to 23.2 wt%.

12. A polyolefin composition comprisingTl) from 85 wt% to 99 wt%; of the terpolymer composition of claims 1-11; T2) from 1.0 wt% to 15.0 wt%; of a copolymer of 1-butene and ethylene containing from 2.5 wt% to 4.8 wt% of ethylene derived units; said copolymer of 1-butene and ethylene having:Melt Flow Rate: measured according to ISO 1133-1 -(190 °C, 2.16 Kg) ranging from 30.0 to 60.0 g / 10 min;the xylene soluble fraction at 0°C, measured according to the method of the examples , ranging from 44 wt% to 68 wt%;melting temperature measured according to Iso 11357-3 ranging from 83°C and 108 °C, form I.

13. The polyolefin composition according to claim 12 wherein component Tl) ranges from 90 wt% to 98 wt and component T2 ranges from 2.0 wt% to 10.0 wt%.

14. The film comprising the polyolefin composition according to claims 12 or 13.

15. The film comprising the terpolymer composition of claims 1-11.

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