COMPONENTS AND CATALYSTS FOR THE POLYMERIZATION OF OLEFINS

Abstract

A solid catalyst component for the polymerization of olefins CH.sub.2═CHR, wherein R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms, made from or containing Mg, Ti, Bi, a halogen and an electron donor.

Claims

1. A solid catalyst component for the polymerization or copolymerization of olefins comprising: titanium, bismuth, magnesium, a halogen, and an electron donor compound which is obtained by a process comprising the following steps: (a) dissolving a magnesium halide in a solvent system comprising an electron donor compound and a liquid hydrocarbon at a temperature higher than 40° C., thereby yielding a solution; (b) cooling the solution to a temperature below 40° C. and adding a titanium compound in a molar excess with respect to the magnesium halide; (c) raising the temperature of the solution to higher than 70° C., thereby obtaining a solid product; and (d) treating the solid product obtained in step (c) with an excess of titanium halide at a temperature higher than 80° C. for one or more times and recovering the solid particles of catalyst component, wherein (i) a bidentate electron donor compound is present in step (c), step (d), or both steps (c) and (d) and (ii) a Bi compound is present in one or more of the steps (a)-(d).

2. The solid 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 solid catalyst component according to claim 2, wherein the Bi compound is Bi trichloride or a Bi decanoate.

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

5. The solid catalyst component according to claim 1, wherein the Bi compound is added in step (a) and dissolved with magnesium halide in the solvent system.

6. The solid catalyst component according to claim 1, wherein the Bi compound is added in step (b) or (d), and dissolved or suspended in a liquid medium comprising the Ti compound.

7. The solid catalyst component according to claim 1, wherein in step (a), after dissolution of the magnesium halide but before carrying out step (b), a dicarboxylic acid anhydride is added to the system.

8. The solid catalyst component according to claim 1, wherein the magnesium halide is magnesium dichloride.

9. The solid catalyst component according to claim 1, wherein the solvent system comprises an electron donor compound selected from the group consisting of aliphatic alcohols having at least 6 carbon atoms, organic epoxy compounds, organic esters of phosphoric acids and mixtures thereof.

10. The solid catalyst component according to claim 1, wherein the titanium compound has the formula TiX.sub.n(OR).sub.4−n wherein X is a halogen, each R is independently a hydrocarbyl group and n is an integer of from 0 to 4.

11. The solid catalyst component according to claim 1, wherein the bidentate electron donor compound is selected from the group consisting of ethers, amines, alkoxysilanes, carbamates, ketones, and esters of aliphatic or aromatic polycarboxylic acids.

12. The solid catalyst component according to claim 11, wherein characterized in that in the bidentate electron donor compound is selected from the group consisting of alkyl and aryl esters of optionally substituted aromatic polycarboxylic acids.

13. The solid catalyst component according to claim 11, wherein bidentate electron donor compound is selected from mixture of esters of aliphatic diacids and 1,3 diethers.

14. A catalyst for the polymerization of olefins CH2=CHR, wherein R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising the product of the reaction between (A) the solid catalyst component according to claim 1, (B) an alkylaluminum compound and, optionally, (C) one or more external electron-donor compounds.

15. A process for the polymerization or copolymerization of olefins CH2=CHR, wherein R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, carried out in the presence of a catalyst according to claim 14.

Description

EXAMPLES

[0067] The following examples are given to better illustrate the invention without limiting it.

Characterizations

Determination of Mg, Ti

[0068] 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”.

[0069] The sample was prepared by analytically weighing, in a “Fluxy” platinum crucible”, 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 crucible was inserted in a “Claisse Fluxy” apparatus for complete burning. 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.

Determination of Bi

[0070] 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”.

[0071] 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.

Determination of Internal Donor Content

[0072] 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.

Determination of X.I.

[0073] 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. %.

Molecular Weight Distribution (Mw/Mn)

[0074] 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-cresole were added to prevent 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).

[0075] 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.

Melt Flow Rate (MIL)

[0076] The melt flow rate (MIL) of the polymer was determined according to ISO 1133 (230° C., 2.16 Kg).

Examples 1-2

[0077] Into a 0.5 L round bottom flask, equipped with a mechanical stirrer, a cooler and a thermometer, 25.3 g of magnesium dichloride, 2.1 g of bismuth (III) chloride, 118 mL of n-decane and 103.8 g of 2-ethylhexyl alcohol were charged at room temperature under nitrogen atmosphere. The reaction mixture was heated at 130° C. and maintained at this temperature for 5.5 h, thereby preparing a homogeneous solution. To this solution, 5.7 g of phthalic anhydride was added. The mixture was stirred at 130° C. for 2 h, thereby dissolving the phthalic anhydride in the homogeneous solution. The homogeneous solution was cooled to room temperature, and 120 mL of the homogeneous solution was added dropwise to 340 mL of titanium tetrachloride kept at −20° C. over a period of 2 h. After completion of the addition, the temperature of the mixed solution was elevated over a period of 3 h to 100° C. The mixture was held at 100° C. for 1 h, then 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 (470 mL) was added. While stirring, diisobutyl phthalate was sequentially added into the flask to meet a Mg/donor molar ratio of 10. The temperature was raised to 120° C. and maintained for 1 h. Thereafter, stirring was stopped. The solid product was allowed to settle, and the supernatant liquid was siphoned off at 120° C. After the supernatant was removed, additional fresh TiCl.sub.4 (470 mL) was added to reach the initial liquid volume again. The mixture was then heated at 120° C. and maintained at this temperature for 0.5 h. Stirring was stopped again. The solid was allowed to settle, and the supernatant liquid was siphoned off. The solid was washed with n-decane kept at 110° C., then two times with anhydrous heptane at 90° C., three times with hexane in temperature gradient down to 60° C., and one time with hexane at room temperature. The resulting solid was dried under vacuum and analyzed. Both the related composition and propylene polymerization performance are indicated in Table 1.

Comparative Examples C1-C2

[0078] Into a 0.5 L round bottom flask, equipped with a mechanical stirrer, a cooler and a thermometer, 25.6 g of magnesium dichloride, 120 mL of n-decane and 105.0 g of 2-ethylhexyl alcohol were charged at room temperature under nitrogen atmosphere. The reaction mixture was heated at 130° C. and maintained at this temperature for 5.0 h, thereby preparing a homogeneous solution. To this solution, 5.7 g of phthalic anhydride was added. The mixture was stirred at 130° C. for 2 h, thereby dissolving the phthalic anhydride in the homogeneous solution. The homogeneous solution was cooled to room temperature, and 120 mL of the homogeneous solution was added dropwise to 340 mL of titanium tetrachloride kept at −20° C. over a period of 2 h. After completion of the addition, the temperature of the mixed solution was elevated over a period of 3 h to 100° C. The mixture was held at 100° C. for 1 h, then 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 (470 mL) was added. While stirring, diisobutyl phthalate was sequentially added into the flask to meet a Mg/donor molar ratio of 10. The temperature was raised to 120° C. and maintained for 1 h. Thereafter, stirring was stopped. The solid product was allowed to settle, and the supernatant liquid was siphoned off at 120° C. After the supernatant was removed, additional fresh TiCl.sub.4 (470 mL) was added to reach the initial liquid volume again. The mixture was then heated at 120° C. and maintained at this temperature for 0.5 h. Stirring was stopped again. The solid was allowed to settle, and the supernatant liquid was siphoned off. The solid was washed with n-decane kept at 110° C., then two times with anhydrous heptane at 90° C., three times with hexane in temperature gradient down to 60° C., and one time with hexane at room temperature. The resulting solid was dried under vacuum and analyzed. Both the related composition and propylene polymerization performance are indicated in Table 1.

Comparative Examples C3-C4

[0079] The catalyst component was prepared according to the procedure described in Examples 1-9 of Patent Cooperation Treaty Publication No. WO2017/042054. Both the related composition and propylene polymerization performance are indicated in Table 1.

General Procedure for the Polymerization of Propylene

[0080] 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. A suspension containing 75 ml of anhydrous hexane, 0.76 g of AlEt.sub.3 (6.66 mmol), 0.33 mmol of external donor and 0.010 g of solid catalyst component, precontacted for 5 minutes, was charged. Dicyclopentyldimethoxysilane, D donor, or cyclohexylmethyldimethoxysilane, C donor, was used as an external donor as reported in Table 1.

[0081] The autoclave was closed and the hydrogen was added (2 NL in D donor tests and 1.5 NL in C donor tests). Then, under stirring, 1.2 kg of liquid propylene was fed. The temperature was raised to 70° C. in about 10 minutes, and the polymerization was carried out at this temperature for 2 hours. At the end of the polymerization, the non-reacted propylene was removed; the polymer was recovered and dried at 70° C. under vacuum for 3 hours. Then the polymer was weighed and characterized.

TABLE-US-00001 TABLE 1 Solid Catalyst Component Mg Polymerization % Ti Bi DIBP ED Mileage XI MIL BDP wt. % wt. % wt. % wt. type Kg/g % wt. g/10’ Mw/Mn Kg/dm.sup.3 Ex. 1 21.0 1.1 1.8 6.9 D 65.3 99.3 1.6 8.1 0.449 Ex. 2 C 53.9 98.9 4.8 7.0 0.461 C1 20.5 2.1 — 6.9 D 84.6 98.7 2.0 9.8 0.434 C2 C 71.4 97.8 5.2 7.6 0.401 C3 20.0 1.0 2.2 6.9 D 64.1 99.0 2.46 — 0.409 C4 C 56.6 98.3 6.58 — 0.424 DIBP = diisobutyl phthalate