Patent ID: 12202180

EXAMPLES

I. Measuring Methods

a) Melt Flow Rate

The melt flow rate (MFR) is determined according to ISO 1133 and is indicated in g/10 min. The MFR is an indication of the flowability and hence the processability of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2of polypropylene is determined ata temperature of 230° C. and under a load of 2.16 kg.

b) DSC Analysis

The crystallisation temperature is measured with a TA Instrument Q2000 differential scanning calorimetry device (DSC) according to ISO 11357/3 on 5 to 10 mg samples, under 50 mL/min of nitrogen atmosphere. Crystallisation temperatures were obtained in a heat/cool/heat cycle with a scan rate of 10° C./min between 30° C. and 225° C. Crystallisation temperatures were taken as the peaks of the endotherms and exotherms in the cooling step and the second heating step respectively.

Fast Scanning Calorimetry (FSC)

A power-compensation-type differential scanning calorimeter Flash DSC1 from MettlerToledo was used to analyze isothermally and non-isothermally the crystallization behavior in the range of cooling rates from 10° to 103K s−1. The instrument was attached to a Huber intracooler TC45, to allow cooling down to about −100° C. The preparation of samples includes cutting of thin sections with thickness of 10 to 15 μm from the surface of pellets. The specimens were heated to 200° C., kept at this temperature for 0.1 s and cooled at different cooling rates to −33° C. which is below the glass transition temperature of the mobile amorphous fraction of iPP. The furnace of the instrument was purged with dry nitrogen gas at a flow rate of 30 mL/min. The sensors were subjected to the so called conditioning procedure which includes several heating and cooling runs. Afterwards, a temperature correction of the sensor was performed. Before loading the sample a thin layer of silicon oil was spread on the heating area of the sample sensor to improve the thermal contact between the sensor and the sample. The sensors are developed by Xensor Integration (Netherlands). Each sensor is supported by a ceramic base plate for easy handling. The total area of the chip is 5.0×3.3 mm2; it contains two separate silicon nitride/oxide membranes with an area of 1.7×1.7 mm2and a thickness of 2.1 mm each, being surrounded by a silicon frame of 300 μm thickness, serving as a heat sink. In the present work additional calibrations were not performed. Further details to the technique as such are given here:E. lervolino, A. van Herwaarden, F. van Herwaarden, E. van de Kerkhof, P. van Grinsven, A. Leenaers, V. Mathot, P. Sarro. Temperature calibration and electrical characterization of the differential scanning calorimeter chip UFS1 for the Mettler-Toledo Flash DSC 1. Thermochim. Acta 522, 53-59 (2011). V. Mathot, M. Pyda, T. Pijpers, G. Poel, E. van de Kerkhof, S. van Herwaarden, F. van Herwaarden, A. Leenaers. The Flash DSC 1, a power compensation twin-type, chip-based fast scanning calorimeter (FSC): First findings of polymers. Thermochim. Acta 552, 36-45 (2011).M. van Drongelen, T. Meijer-Vissers, D. Cavallo, G. Portale, G. Vanden Poel, R. Androsch R. Microfocus wide-angle X-ray scattering of polymers crystallized in a fast scanning chip calorimeter. Thermochim Acta 563, 33-37 (2013).
c) Comonomer Content
Poly(propylene-co-ethylene)—Ethylene Content by IR Spectroscopy

Quantitative infrared (IR) spectroscopy was used to quantify the ethylene content of the poly(ethylene-co-propene) copolymers through calibration to a primary method.

Calibration was facilitated through the use of a set of in-house non-commercial calibration standards of known ethylene contents determined by quantitative13C solution-state nuclear magnetic resonance (NMR) spectroscopy. The calibration procedure was undertaken in the conventional manner well documented in the literature. The calibration set consisted of 38 calibration standards with ethylene contents ranging 0.2-75.0 wt % produced at either pilot or full scale under a variety of conditions. The calibration set was selected to reflect the typical variety of copolymers encountered by the final quantitative IR spectroscopy method.

Quantitative IR spectra were recorded in the solid-state using a Bruker Vertex 70 FTIR spectrometer. Spectra were recorded on 25×25 mm square films of 300 um thickness prepared by compression moulding at 180-210° C. and 4-6 mPa. For samples with very high ethylene contents (>50 mol %) 100 um thick films were used. Standard transmission FTIR spectroscopy was employed using a spectral range of 5000-500 cm−1, an aperture of 6 mm, a spectral resolution of 2 cm−1, 16 background scans, 16 spectrum scans, an interferogram zero filling factor of 64 and Blackmann-Harris 3-term apodisation.

Quantitative analysis was undertaken using the total area of the CH2rocking deformations at 730 and 720 cm−1(AQ) corresponding to (CH2)>2structural units (integration method G, limits 762 and 694 cm−1). The quantitative band was normalised to the area of the CH band at 4323 cm−1(AR) corresponding to CH structural units (integration method G, limits 4650, 4007 cm−1). The ethylene content in units of weight percent was then predicted from the normalised absorption (AQ/AR) using a quadratic calibration curve. The calibration curve having previously been constructed by ordinary least squares (OLS) regression of the normalised absorptions and primary comonomer contents measured on the calibration set.

Poly(propylene-co-ethylene)—Ethylene Content for Calibration Using13C NMR Spectroscopy

Quantitative13C{1H} NMR spectra were recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 10 mm extended temperature probehead at 125° C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2(TCE-d2) along with chromium (III) acetylacetonate (Cr(acac)3) resulting in a 65 mM solution of relaxation agent in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225, Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6 k) transients were acquired per spectra. Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, H. N., Macromolecules 17 (1984), 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer: fE=(E/(P+E) The comonomer fraction was quantified using the method of Wang et. al. (VVang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) through integration of multiple signals across the whole spectral region in the13C{1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents. The mole percent comonomer incorporation was calculated from the mole fraction: E [mol %]=100*fE. The weight percent comonomer incorporation was calculated from the mole fraction: E [wt %]=100*(fE*28.06)/((fE*28.06)+((1−fE)*42.08))

d) Xylene Soluble Content (XCS, Wt %)

The content of the polymer soluble in xylene is determined according to ISO 16152; 5thedition; 2005-07-01 at 25° C.

e) Tensile Modulus

Tensile Modulus is measured according to ISO 527-1:2012/IS0527-2:2012 at 23° C. and at a cross head speed=50 mm/min; using injection moulded test specimens as described in EN ISO 1873-2 (dog bone shape, 4 mm thickness).

f) Charpy Notched Impact

Charpy notched impact strength is determined according to ISO 179/1eA at 23° C. on injection moulded test specimens as described in EN ISO 1873-2 (80×10×4 mm).

g) Haze

Haze is determined according to ASTM D1003 on injection moulded plaques having 1 mm thickness and 60×60 mm2area produced as described in EN ISO 1873-2.

h) Crystex Analysis

Crystalline and Soluble Fractions Method

The crystalline (CF) and soluble fractions (SF) of the polypropylene (PP) compositions as well as the comonomer content and intrinsic viscosities of the respective fractions were analysed by the CRYSTEX QC, Polymer Char (Valencia, Spain).

A schematic representation of the CRYSTEX QC instrument is shown inFIG.2a. The crystalline and amorphous fractions are separated through temperature cycles of dissolution at 160° C., crystallization at 40° C. and re-dissolution in a 1,2,4-trichlorobenzene (1,2,4-TCB) at 160° C. as shown inFIG.1b. Quantification of SF and CF and determination of ethylene content (C2) are achieved by means of an infrared detector (IR4) and an online 2-capillary viscometer which is used for the determination of the intrinsic viscosity (IV).

The IR4 detector is a multiple wavelength detector detecting IR absorbance at two different bands (CH3 and CH2) for the determination of the concentration and the Ethylene content in Ethylene-Propylene copolymers. 1R4 detector is calibrated with series of 8 EP copolymers with known Ethylene content in the range of 2 wt.-% to 69 wt.-% (determined by 13C-NMR) and various concentration between 2 and 13 mg/ml for each used EP copolymer used for calibration.

The amount of Soluble fraction (SF) and Crystalline Fraction (CF) are correlated through the XS calibration to the “Xylene Cold Soluble” (XCS) quantity and respectively Xylene Cold Insoluble (XCI) fractions, determined according to standard gravimetric method as per ISO16152. XS calibration is achieved by testing various EP copolymers with XS content in the range 2-31 Wt %.

The intrinsic viscosity (IV) of the parent EP copolymer and its soluble and crystalline fractions are determined with a use of an online 2-capillary viscometer and are correlated to corresponding IV's determined by standard method in decalin according to ISO 1628. Calibration is achieved with various EP PP copolymers with IV=2-4 dL/g.

A sample of the PP composition to be analysed is weighed out in concentrations of 10 mg/ml to 20 mg/ml. After automated filling of the vial with 1,2,4-TCB containing 250 mg/l 2,6-tert-butyl-4-methylphenol (BHT) as antioxidant, the sample is dissolved at 160° C. until complete dissolution is achieved, usually for 60 min, with constant stirring of 800 rpm.

As shown in aFIGS.2aand2b, a defined volume of the sample solution is injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part is taking place. This process is repeated two times. During the first injection the whole sample is measured at high temperature, determining the IV[dl/g] and the C2[wt %] of the PP composition. During the second injection the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) with the crystallization cycle are measured (Wt % SF, Wt % C2, IV).

EP means ethylene propylene copolymer.

PP means polypropylene.

II. Inventive Example

a) Catalyst ppreparation

For the preparation of the catalyst 3.4 litre of 2-ethylhexanol and 810 ml of propylene glycol butyl monoether (in a molar ratio 4/1) were added to a 20.0 l reactor. Then 7.8 litre of a 20.0% solution in toluene of BEM (butyl ethyl magnesium) provided by Crompton GmbH, were slowly added to the well stirred alcohol mixture. During the addition, the temperature was kept at 10.0° C. After addition, the temperature of the reaction mixture was raised to 60.0° C. and mixing was continued at this temperature for 30 minutes. Finally after cooling to room temperature the obtained Mg-alkoxide was transferred to a storage vessel.

21.2 g of Mg alkoxide prepared above was mixed with 4.0 ml bis(2-ethylhexyl) citraconate for 5 min. After mixing the obtained Mg complex was used immediately in the preparation of the catalyst component.

19.5 ml of titanium tetrachloride was placed in a 300 ml reactor equipped with a mechanical stirrer at 25.0° C. Mixing speed was adjusted to 170 rpm. 26.0 g of Mg-complex prepared above was added within 30 minutes keeping the temperature at 25.0° C. 3.0 ml of Viscoplex® 1-254 and 1.0 ml of a toluene solution with 2 mg Necadd 447™ was added. Then 24.0 ml of heptane was added to form an emulsion. Mixing was continued for 30 minutes at 25.0° C., after which the reactor temperature was raised to 90.0° C. within 30 minutes. The reaction mixture was stirred for a further 30 minutes at 90.0° C. Afterwards stirring was stopped and the reaction mixture was allowed to settle for 15 minutes at 90.0° C. The solid material was washed 5 times: washings were made at 80.0° C. under stirring for 30 min with 170 rpm. After stirring was stopped the reaction mixture was allowed to settle for 20-30 minutes and followed by siphoning.Wash 1: washing was made with a mixture of 100 ml of toluene and 1 ml donorWash 2: washing was made with a mixture of 30 ml of TiCl4 and 1 ml of donor.Wash 3: washing was made with 100 ml of toluene.Wash 4: washing was made with 60 ml of heptane.Wash 5: washing was made with 60 ml of heptane under 10 minutes stirring.

Afterwards stirring was stopped and the reaction mixture was allowed to settle for 10 minutes while decreasing the temperature to 70° C. with subsequent siphoning, followed by N2sparging for 20 minutes to yield an air sensitive powder.

Inventive example (IE) was produced in a pilot plant with a prepolymerization reactor, one slurry loop reactor and two gas phase reactors. The solid catalyst component described above along with triethyl-aluminium (TEAL) as co-catalyst and dicyclopentyl dimethoxy silane (D-donor) as external donor, were used in the inventive process.

The polymerization process conditions and properties of the propylene polymer fractions are described in Table 1.

The polypropylene composition is then extruded with a nucleating agent in a co-rotating twin screw extruder type Coperion ZSK 40 (screw diameter 40 mm, L/D ratio 38). The temperatures in the extruder were in the range of 190-230° C. In the inventive example, 0.05 wt % of Irganox 1010 (Pentaerythrityl-tetrakis(3-(3′,5′-di-tert. butyl-4-hydroxyphenyl)-propionate, CAS No. 6683-19-8, commercially available from BASF AG, Germany), 0.05 wt % of Irgafos 168 (Tris (2,4-di-t-butylphenyl) phosphite, CAS No. 31570-04-4, commercially available from BASF AG, Germany), 0.10 wt % of Calcium stearate (CAS. No. 1592-23-0, commercially available under the trade name Ceasit FI from Baerlocher GmbH, Germany) and 0.06 wt % of Glycerol monostearate (CAS No. 97593-29-8, commercially available with 90% purity under the trade name Grindsted PS 426 from Danisco A/S, Denmark), 0.17 wt % Millad 3988 (CAS No. 135861-56-2, Milliken) were added to the extruder as additives. 0.3 ppm of Poly Vinyl Cyclo Hexane (PVCH) was added via a nucleating masterbatch

Said nucleating masterbatch is a PP-homopolymer, MFR 20, and comprises ca 15 ppm of PVCH as polymeric nucleating agent.

Following the extrusion step and after solidification of the strands in a water bath, the resulting polypropylene composition was pelletized in a strand pelletizer.

TABLE 1Polymerization process conditions and propertiesof the propylene polymer fractionsIE1Pre-polymerization reactorTemperature[° C.]30Catalyst feed[g/h]4.4TEAL/propylene[g/t propylene]170Residence Time[min]20Loop reactor (first propylene polymer fraction)Temperature[° C.]70Pressure[kPa]5400Split[%]46.8H2/C3ratio[mol/kmol]1.9C2/C3ratio[mol/kmol]3.2MFR2[g/10 min]22C2content after loop[wt %]0.5reactorFirst gas-phase reactor -Temperature[° C.]80Pressure[kPa]1820Split[%]43.2H2/C3ratio[mol/kmol]27.1C2/C3ratio[mol/kmol]7.9MFR2[g/10 min]17.4C2content after 1stgas[wt %]1.4hase reactorSecond gas-phase reactor -Temperature[° C.]80Pressure[kPa]2500Split[%]10H2/C3ratio[mol/kmol]27.5C2/C3ratio[mol/kmol]68.9MFR2[g/10 min]17.3C2content final[wt %]2.5C2 ratio (final/fraction 1)0.2*Split relates to the amount of propylene polymer produced in each specific reactor.

Its properties are compared to RE420MO (a polypropylene random copolymer of MFR 13 g/10 min and IE2 of WO2009/021686).

Results are presented inFIG.1and table 2. As can be seen inFIG.1, the inventive example shows mono-crystalline behaviour (no transition to mesophase) with cooling rate up to 600 k/s.

The comparative example has a much lower cooling rate. Starting from 50 K/s, a new crystallisation peak appears at a much lower Tc which is the crystallisation of the mesophase. Crystallisation stops at the cooling rate of 200 k/s.

IE1 has much faster crystallisation rate measured as Tc with a broader cooling rate range.

TABLE 2Polypropylene composition properties.CEIE1MFR-finalg/10 min1317.3Tensile modulusMPa11241398Tensile strengthMPa2933NIS-BkJ/m26.25.8Haze-1 mm%1618.1SFwt %8.028.2C2wt %3.032.5C2(SF)wt %15.312.4C2(CF)wt %2.51.7IVdl/g1.71.6IV(SF)dl/g0.50.6IV(CF)dl/g1.81.7Top load force on capN15531741

Screw caps type PCO 1810 were made by injection moulding the polypropylene composition on an ENGEL Speed 180/45 injection moulding machine, equipped with a 12 cavity tool for screw caps.

The tool was supplied by Husky/KTW.

Injection moulding was done with an injection speed: 170 cm3/sec, a holding pressure. 860 bar and melt temperature of 230° C. or 240° C. and tool temperature of 12° C.

Cycle and cooling times are given in Table 3 to 5.

TABLE 3Crystallisation temperatures at fast cooling ratesCooling rate [K/sec]CE (RE420MO)IEK/sTc. monoTc. mesoTc. mono0.051240.161201270.511611021162971133941124911105901086891087881068861069851051084104208199307596407293507026916065238970592187805819859055178410054158320052117230063400585005760053

TABLE 4Processing behaviour of the Inventive Exampleat various cycle times and mass temperaturesInventive exampleCoolingCycle-timetimeMass TemperatureMass Temperature[sec][sec.]240° C.230° C.5.12.5Good (minimal AngelGood (minimal AngelHair & high tips)Hair & high tips)4.92.3Good (High Tips)Good (minimal AngelHair & high tips)4.72.1sometimes demouldingsometimes demouldingproblemsproblems4.51.9Demoulding problemsDemoulding problems(ring tears off)4.31.7Not PossibleDemoulding problems(ring tears off)

TABLE 5Processing behaviour of the comparative Exampleat various cycle times and mass temperaturesComparative ExampleCoolingCycle-timetimeMass TemperatureMass Temperature[sec][sec.]240° C.230° C.5.12.5Good (minimal AngelGood (minimal AngelHair & high tips)Hair & high tips)4.92.3DemouldingGood (minimal AngelproblemsHair & high tips)4.72.1major demouldingDemouldingproblems (ringproblemstears off)4.51.9Not Possiblemajor demouldingproblems (ringtears off)4.31.7Not PossibleNot Possible