Components and catalysts for the polymerization of olefins

Abstract

A solid catalyst component for the polymerization of olefins CH.sub.2═CHR in which R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms, made from or containing Mg, Ti, Bi, halogen and an electron donor obtained from a process including the steps: (a) dissolving a Mg(OR).sub.2 compound wherein R groups, equal to or different from each other, are C.sub.1-C.sub.15 hydrocarbon groups optionally containing a heteroatom selected from O, N and halogen, in an organic liquid medium, thereby forming a first liquid mixture; (b) contacting the first liquid mixture (a) with TiCl.sub.4, thereby forming a second liquid mixture absent a solid phase, and (c) subjecting the second liquid mixture (b) to conditions, whereby solid catalyst particles are formed, wherein (i) a Bi compound and (ii) a bidentate electron donor compound are present in one or more of steps (a) to (c) and/or contacted with the solid catalyst particles obtained from (c).

Claims

1. A solid catalyst component for the polymerization or copolymerization of olefins CH.sub.2=CHR wherein R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms comprising titanium, magnesium, halogen, bismuth and an electron donor compound obtained by a process comprising the following steps: (a) dissolving a Mg(OR).sub.2 compound wherein R groups, equal to or different from each other, are C.sub.1-C.sub.15 hydrocarbon groups optionally containing a heteroatom selected from O, N and halogen, in an organic liquid medium, thereby forming a first liquid mixture; (b) contacting the first liquid mixture of step (a) with TiCl.sub.4, thereby forming a second liquid mixture absent a solid phase, and (c) subjecting the second liquid mixture of step (b) to conditions, whereby solid catalyst particles are formed, wherein (i) a Bi compound and (ii) a bidentate electron donor compound are present in one or more of steps (a) to (c) and/or contacted with the solid catalyst particles obtained from step (c).

2. The catalyst component according to claim 1, wherein the Bi compound is selected from the group consisting of Bi halides, Bi carbonate, Bi carboxylates, Bi nitrate, Bi oxide, Bi sulphate and Bi sulfide.

3. The catalyst component according to claim 2, wherein the Bi compound is selected from the group consisting of Bi trichloride and a Bi decanoate.

4. The catalyst component according to claim 1, wherein the Bi compound is used in an amount ranging from 0.005 to 0.2 mole per mole of Mg.

5. The catalyst component according to claim 1, wherein the Mg(OR).sub.2 compound is a magnesium alkoxide wherein R is a C.sub.1-C.sub.15 alkyl group or has the structure of an ether group —ROR wherein R is a C.sub.1-C.sub.15 alkyl group as well.

6. The catalyst component according to claim 1, wherein in step (b), the second liquid mixture is prepared by reacting the Mg alkoxide with TiCl.sub.4, a titanium alkoxide, a phenolic compound and an alkanol in an inert liquid diluent.

7. The catalyst component according to claim 6, wherein the alkoxy groups of the Mg alkoxide, alkanol and those of the Ti alkoxides, independently have up to 4 carbon atoms inclusive.

8. The catalyst component according to claim 6, wherein the reaction step (b) is carried out according to the following scheme carried out at a temperature ranging from 30 to 120° C.:
3Mg(OEt).sub.2+xTi(OEt).sub.4+yTiCl.sub.4+z o-cresol+nEtOH. wherein y is more than 0.1 but less than about 0.8, (x+y) is more than 0.2 but less than 3, z is more than 0.05 but less than 3, and n is more than about 0.5 but less than about 9.

9. The catalyst component according to claim 8, wherein step (c) comprises raising the temperature, thereby removing the alkanol and causing solidification of particles.

10. The catalyst component according to claim 1, wherein the bidentate electron donor is selected from the group consisting of ethers, amines, silanes, carbamates, ketones, esters of aliphatic acids, alkyl and aryl esters of optionally substituted aromatic polycarboxylic acids, diol derivatives containing ester, carbamates, carbonates, amides groups or mixtures thereof.

11. The catalyst component according to claim 1, wherein in a further step (d), the bidentate electron donor and optionally, a tetravalent titanium halide, are contacted with the solidified particles obtained from step (c).

12. The catalyst component according to claim 1, wherein in step (b), the Mg alkoxide solution is mixed with TiCl.sub.4 at a temperature of about −20° C. to about 30° C. and in the presence of a surfactant and in the successive step (c), precipitation of the solid catalyst components is obtained by slowly raising the temperature to at least 50° C.

13. The catalyst component according to claim 12, wherein the bidentate electron donor is added to the Mg alkoxide solution prepared in step (a).

14. The catalyst component according to claim 1, wherein the Mg alkoxide solution in a C.sub.6-C.sub.10 aromatic liquid reaction medium prepared in step (a), is first contacted with the electron donor or precursor thereof, thereby obtaining a further solution; in step (b), the solution obtained in step (a) is reacted with titanium tetrahalide at a temperature greater than 10° C. and less than 60° C., thereby producing an emulsion of a denser, TiCl.sub.4/toluene-insoluble, oil dispersed phase having a Ti/Mg mol ratio 0.1 to 10 in an oil disperse phase having Ti/Mg mol ratio 10 to 100, in the presence of an emulsion stabilizer.

15. The catalyst component according to claim 14, wherein in step (c), solidification of the dispersed phase droplets by heating is carried out at a temperature of 70-150° C.

Description

EXAMPLES

(1) The following examples are given to better illustrate the invention without limiting it.

(2) Characterizations

(3) Determination of Mg, Ti

(4) The determination of Mg and Ti content in the solid catalyst component was carried out via inductively coupled plasma emission spectroscopy on “I.C.P Spectrometer ARL Accuris”.

(5) The sample was prepared by analytically weighing 0.1=0.3 grams of catalyst and 2 grams of lithium metaborate/tetraborate 1/1 mixture. After addition of some drops of KI solution, the sample was completely burned. The residue was collected with a 5% v/v HNO.sub.3 solution and then analyzed via ICP at the following wavelengths: Magnesium, 279.08 nm; Titanium, 368.52 nm.

(6) Determination of Bi

(7) The determination of Bi content in the solid catalyst component was carried out via inductively coupled plasma emission spectroscopy on “I.C.P Spectrometer ARL Accuris”. The sample was prepared by analytically weighing in a 200 milliliters volumetric flask 0.1-0.3 grams of catalyst. After slow addition of both about 20 milliliters of H.sub.2SO.sub.4 95-98% and about 50 milliliters of distilled water, the sample underwent a digestion for 12 hours. Then the volumetric flask was diluted to the mark with deionized water. The resulting solution was directly analyzed via ICP at the following wavelength: bismuth, 223.06 nm.

(8) Determination of Internal Donor Content

(9) The content of internal donor in the solid catalytic compound was determined by gas chromatography. The solid component was dissolved in acetone, an internal reference was added, and a sample of the organic phase was analyzed in a gas chromatograph, thereby determining the amount of donor present at the starting catalyst compound.

(10) Determination of X.I.

(11) 2.5 g of polymer and 250 ml of o-xylene were placed in a round-bottomed flask provided with a cooler and a reflux condenser and kept under nitrogen. The resulting mixture was heated to 135° C. and kept under stirring for about 60 minutes. The final solution was allowed to cool to 25° C. under continuous stirring, and the insoluble polymer was then filtered. The filtrate was then evaporated in a nitrogen flow at 140° C. to reach a constant weight. The content of the xylene-soluble fraction is expressed as a percentage of the original 2.5 grams and then, by difference, the X.I. %.

(12) Molecular Weight Distribution (Mw/Mn)

(13) Molecular Weight and Molecular Weight Distribution (MWD) were measured by Gel Permeation Chromatography (GPC) in 1,2,4-trichlorobenzene (TCB). Molecular weight parameters (M.sub.n, M.sub.w, M.sub.z) and molecular weight distributions for the samples were measured using a GPC-IR apparatus by PolymerChar, which was equipped with a column set of four PLgel Olexis mixed-bed (Polymer Laboratories) and an IR5 infrared detector (PolymerChar). The dimensions of the columns were 300×7.5 mm and their particle size 13 μm. The mobile phase flow rate was kept at 1.0 mL/min. The measurements were carried out at 150° C. Solution concentrations were 2.0 mg/mL (at 150° C.) and 0.3 g/L of 2,6-di-tertbutyl-p-cresol were added, thereby preventing degradation. For GPC calculation, a universal calibration curve was obtained using 12 polystyrene (PS) standard samples supplied by PolymerChar (peak molecular weights ranging from 266 to 1220000). A third order polynomial fit was used for interpolating the experimental data and obtain the relevant calibration curve. Data acquisition and processing was done by using Empower 3 (Waters).

(14) The Mark-Houwink relationship was used to determine the molecular weight distribution and the relevant average molecular weights: the K values were K.sub.PS=1.21×10.sup.−4 dL/g and K.sub.PP=1.90×10.sup.−4 dL/g for polystyrene (PS) and polypropylene (PP) respectively, while the Mark-Houwink exponents α=0.706 for PS and α=0.725 for PP were used.

(15) Melt Flow Rate (MIL)

(16) The melt flow rate (MIL) of the polymer was determined according to ISO 1133 (230° C., 2.16 Kg).

(17) .sup.13C NMR of Propylene/Ethylene Copolymers

(18) .sup.13C NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with cryoprobe, operating at 160.91 MHz in the Fourier transform mode at 120° C. The peak of the S66 carbon (nomenclature according to “Monomer Sequence Distribution in Ethylene-Propylene Rubber Measured by 13C NMR. 3. Use of Reaction Probability Mode” C. J. Carman, R. A. Harrington and C. E. Wilkes, Macromolecules, 1977, 10, 536) was used as an internal reference at 29.9 ppm. The samples were dissolved in 1,1,2,2-tetrachloroethane-d2 at 120° C. with an 8% wt/v concentration. Each spectrum was acquired with a 90° pulse, 15 seconds of delay between pulses and CPD to remove .sup.1H-.sup.13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz.

(19) The assignments of the spectra, the evaluation of triad distribution and the composition were made according to Kakugo (“Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with 6-titanium trichloride-diethylaluminum chloride” M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 1982, 15, 1150) using the following equations:

(20) $\begin{array}{ccc}\mathrm{PPP}=100T_{\mathrm{\beta \beta }}/S& \mathrm{PPE}=100T_{\mathrm{\beta \delta }}/S& \mathrm{EPE}=100T_{\mathrm{\delta \delta }}/S\\ \mathrm{PEP}=100S_{\mathrm{\beta \beta }}/S& \mathrm{PEE}=100S_{\mathrm{\beta \delta }}/S& \mathrm{EEE}=\begin{array}{c}100(0.25S_{\mathrm{\gamma \delta }}+\\ 0.5S_{\mathrm{\delta \delta }})/S\end{array}\end{array}$$S=T_{\mathrm{\beta \beta }}+T_{\mathrm{\beta \delta }}+T_{\mathrm{\delta \delta }}+S_{\mathrm{\beta \beta }}+S_{\mathrm{\beta \delta }}+0.25S_{\mathrm{\gamma \delta }}+0.5S_{\mathrm{\delta \delta }}$

(21) The molar percentage of ethylene content was evaluated using the following equation: E % mol=100*[PEP+PEE+EEE]

(22) The weight percentage of ethylene content was evaluated using the following equation:

(23) $E\%\mathrm{wt}.=\frac{100*E\%\mathrm{mol}*{\mathrm{MW}}_E}{E\%\mathrm{mol}*{\mathrm{MW}}_E+P\%\mathrm{mol}*{\mathrm{MW}}_P}$
where P % mol is the molar percentage of propylene content, while MW.sub.E and MW.sub.P are the molecular weights of ethylene and propylene, respectively.
General Procedure for the Preparation of Propylene/Ethylene Copolymers

(24) A 4-liter steel autoclave equipped with a stirrer, a pressure gauge, a thermometer, a catalyst feeding system, monomer feeding lines and a thermostatic jacket, was purged with nitrogen flow at 70° C. for one hour. Then, at 30° C. under propylene flow (0.5 bar), a suspension containing 75 ml of anhydrous hexane, 0.76 g of AlEt.sub.3, 3.3 mmol of diclopentyldimethoxysilane (D donor) and from 0.004 to 0.010 g of solid catalyst component, precontacted for 5 minutes, was charged. The autoclave was closed; subsequently hydrogen was added, as reported in Table 1. Then, under stirring, 1.2 kg of liquid propylene with ethylene (4 g) was fed during the raising of temperature from 30 up to 70° C. The temperature was raised to 70° C. in about 10-15 minutes and the polymerization was carried out at this temperature for two hours and ethylene was fed during the polymerization to keep the pressure constant. At the end of the polymerization, the non-reacted monomers were removed; the polymer was recovered and dried at 70° C. under vacuum for three hours. Then the polymer was weighed and characterized.

Example 1

(25) A catalyst precursor of formula Mg.sub.3Ti(OEt).sub.8Cl.sub.2 was prepared as described in U.S. Pat. No. 5,077,357 (Illustrative Embodiment II).

(26) Into a 500 ml round bottom flask, equipped with a mechanical stirrer, a cooler and a thermometer, 105 ml of TiCl.sub.4 and 105 ml of chlorobenzene were introduced at room temperature under nitrogen atmosphere. After cooling to 0° C., while stirring, BiCl.sub.3 in a powder form and in an amount such as to have a Mg/Bi molar ratio of 20, diisobutylphthalate (DIBP) in an amount such as to have a Mg/DIBP molar ratio of 10, and 10.3 g of a Mg based precursor were sequentially added into the flask. The temperature was raised to 100° C. and maintained for 1 hour. Thereafter, stirring was stopped, the solid product was allowed to settle, and the supernatant liquid was siphoned off at 100° C. After the supernatant was removed, additional fresh TiCl.sub.4 and chlorobenzene was added at room temperature. The mixture was then heated at 120° C. and kept at this temperature for 60 minutes. Stirring was stopped again, the solid was allowed to settle and the supernatant liquid was siphoned off at 100° C. The solid was washed with anhydrous heptane four times in temperature gradient down to 90° C. and one time at 25° C. The resulting solid was then dried under vacuum and analyzed.
The catalyst component was used in the copolymerization of propylene with ethylene. The results are reported in Table 1.

Comparative Example C1

(27) The procedure described in Example 1 was repeated with the exception that BiCl.sub.3 was not used. The catalyst component was used in the copolymerization of propylene with ethylene. The results are reported in Table 1.

Comparative Example C2

(28) DIBP based catalyst was prepared as described in Patent Cooperation Treaty Publication No. WO2017/042058 (examples 1-12), employing BiCl.sub.3 dissolved in TiCl.sub.4.

Comparative Example C3

(29) DIBP based catalyst prepared as in C2 without using BiCl.sub.3.

(30) TABLE-US-00001 TABLE 1 Solid Catalyst Component Mg Ti Bi DIBP C2 Mileage XI MIL % wt. % wt. % wt. % wt. % wt Kg/g % wt. g/10′ Ex. 1 20.9 1.6 1.4  6.8 4.1 184 94.6 5.4 Ex. 2 3.8 170 95.2 5.1 C1 19.3 3.0 — 11.1 3.8 108 93.2 7.7 C2 18.7 2 2 13.0 3.4 130 95.6 4.9 C3 18.7 2.7 11.3 3.2 120 94.7 4.2 DIBP = diisobutyl phthalate