阅读说明：本技术 烯烃聚合的催化剂组分 (catalyst components for the polymerization of olefins ) 是由 D·布丽塔 S·圭多蒂 于 2018-05-09 设计创作，主要内容包括：一种催化剂混合物,包含(a)固体催化剂组分颗粒,该固体催化剂组分包含Ti、Mg、Cl和0.2-5.0重量％的粒度为0.1μm-1mm的无机固体化合物颗粒,其含有大于50重量％的SiO<Sub>2</Sub>单元。(A catalyst mixture comprising (a) particles of a solid catalyst component comprising Ti, Mg, Cl and 0.2-5.0 wt% of particles of an inorganic solid compound having a particle size of 0.1 μm-1mm, which contains more than 50 wt% of SiO2 units.)

1. A catalyst mixture comprising a mechanical mixture of: (a) particles of a solid catalyst component comprising titanium (Ti), magnesium (Mg) and chloride (Cl), and (b)0.2-5.0 wt% of particles of a solid compound having a particle size of 0.1 μm to 1mm and containing more than 50 wt% of SiO2 units.

2. the catalyst mixture according to claim 1 in which the solid compound (b) containing more than 50% by weight of SiO2 units is selected from the group consisting of silica, silicates and diatomaceous earth and mixtures thereof.

3. The catalyst mixture according to claim 2, wherein the solid compound (b) containing more than 50% by weight of SiO2 units is selected from phyllosilicates.

4. The catalyst mixture according to claim 3, wherein the phyllosilicate is talc.

5. The catalyst mixture according to claim 1, wherein the particle size of the solid compound (b) is 2-800 μm.

6. The catalyst mixture according to claim 1, wherein the solid compound (b) containing more than 50% by weight of SiO2 units is selected from silica.

7. The catalyst mixture of claim 6, wherein the silica is crystalline silica.

8. The catalyst mixture of claim 7, wherein the silica has a particle size of 0.1-5 μm.

9. The catalyst mixture according to claim 1, wherein the particle size of the solid catalyst component (a) ranges from 4 to 120 μm.

10. The catalyst mixture according to claim 9, wherein the sphericity factor of the solid catalyst component (a) is higher than 0.60.

11. The catalyst mixture according to claim 10, wherein the solid catalyst component (a) has a sphericity factor higher than 0.7 and a particle size of 10-90 μm.

12. The catalyst mixture according to any of the preceding claims, wherein the amount of particles of the solid compound (b) is 0.5-5 wt%.

13. The catalyst mixture according to claim 1, wherein the solid catalyst component (a) further comprises an electron donor selected from the group consisting of esters, ethers, amines, silanes, carbamates and ketones and mixtures thereof.

14. A catalyst system for the (co) polymerization of olefins (CH2 ═ CHR) wherein R is hydrogen or a hydrocarbon group having 1 to 12 carbon atoms, comprising the product obtained by contacting:

(i) The catalyst mixture of claim 1;

(ii) An alkyl aluminum compound, and

(iii) Optionally an external electron donor compound.

15. A process for the (co) polymerization of the olefin CH2 ═ CHR, wherein R is hydrogen or a hydrocarbon group having from 1 to 12 carbon atoms, carried out in the presence of said catalyst system according to claim 14.

Technical Field

The present disclosure relates to a catalyst component for the (co) polymerization of olefins with improved flowability, including catalysts obtained from the catalyst component and their use in olefin (co) polymerization processes.

Background

The Ziegler-Natta catalyst component may be used for the stereospecific polymerization of olefins such as propylene. A first catalyst of this type, widely used in industry, comprises solid TiCl3 obtained by reduction of TiCl4 with an alkylaluminum compound. However, the activity and stereospecificity of the catalyst are generally not commercially viable, and the resulting polymer must be subjected to a deashing treatment to remove catalyst residues, and a washing step to remove any resulting random polymer. The catalysts currently used generally comprise a solid catalyst component further comprising a magnesium dihalide and one or more supported titanium compounds, an internal electron donor compound and an aluminum alkyl compound as cocatalyst.

The particle size of the catalyst may be from about 5 to about 200 μm, depending on the type of polymerization technique that may be used. However, this size range may be affected by agglomeration problems which deteriorate the flowability and reduce the uniform distribution of the catalyst particles in the reactor.

To address these problems, slip agents such as stearates or erucamide have been used. However, these additives generally do not improve the flow characteristics. U.S. patent application publication No. 2015/0344667 suggests coating catalyst or support particles with a layer of nanoparticles made of a conductive material, such as carbon black. However, this process is cumbersome, as an additional separate step has to be performed to prepare the gel comprising the nanoparticles. Furthermore, the presence of the additional layer may prevent the necessary interaction between the catalytically active metal and the support. In addition, the process involves the use of water-based nanoparticle gels, which can deactivate Ti-based catalysts.

Therefore, there is a need for a simple method of improving the flowability of a catalyst without impairing its catalytic performance.

The applicants have therefore surprisingly found that enhanced catalyst flowability can be obtained by mechanically mixing particles of the catalyst component with a small amount of isolated inorganic particles having a specific composition.

Disclosure of Invention

An object of the present disclosure relates to a catalyst mixture comprising a mechanical mixture of: (a) particles of a solid catalyst component comprising titanium (Ti), magnesium (Mg) and chloride (Cl), and (b)0.2-5.0 wt% of particles of a solid compound having a particle size of 0.1 μm to 1mm and containing more than 50 wt% of SiO2 units.

Detailed Description

The term mechanical mixture indicates that the particles of the solid catalyst component (a) are distinct and separate from the particles of the solid compound (b). The particles of the catalyst component (a) and the particles of the compound (b) are brought into close proximity to each other by mechanical mixing.

Preferably, in the catalyst mixture of the present disclosure, the particle size of the inorganic solid compound ranges from 2 to 800 μm, more preferably from 1 to 100 μm, especially from 1 to 30 μm.

Preferably, the solid compound (b) containing more than 50% by weight of SiO2 units is selected from the group consisting of silica, silicates and diatomaceous earth. Among the silicates, particularly preferred are phyllosilicates, such as talc. A preferred type of silica is hydrophilic silica, i.e. silica which has not been modified to make it hydrophobic. Among them, crystalline silica having a size of 0.1 to 5 μm in particular is preferably used. The term crystalline silica refers to silica-based materials that exhibit an X-ray spectrum with sharp reflections similar to quartz or cristobalite.

further, diatomaceous earth is preferably used. Among them, diatomaceous earth commercialized under the name of diatomaceous earth is particularly preferably used.

the particle size of the solid catalyst component is preferably from 4 to 120. mu.m, more preferably from 8 to 100. mu.m, in particular from 10 to 90 μm.

Preferably, the amount of particles of solid compound (b) is from 0.5 to 5%, more preferably from 0.75 to 4%, especially from 1 to 3% by weight, based on the total weight of the catalyst mixture (a) + (b).

the solid catalyst component may be in the form of granules, spherical irregularities or spherical regularity.

granular or other irregular catalyst particles may be obtained by reacting a Ti-halide with a precursor of the general formula MgXn (OR)2-n, where X is Cl or a C1-C10 hydrocarbon group, R is a C1-C8 alkyl group, and n is 0-2. The solid particles resulting from this reaction consist essentially of MgCl2 on which the Ti compound is immobilized.

The catalyst component having a spherical morphology may be obtained by reacting a Ti-halide with a precursor comprising an adduct of formula MgCl2(R1OH) n, wherein R is a C1-C8 alkyl group, preferably ethyl, and n is from 2 to 6.

Preferred solid catalyst components according to the present disclosure are those having a predominantly spherical shape. In particular, those with a sphericity factor higher than 0.60 and preferably higher than 0.70 are preferred. The sphericity factor is calculated using the image analysis techniques described in the characterization section of the present application.

according to a particular embodiment, the solid catalyst component has a sphericity factor higher than 0.7 and a particle size of 10 to 90 μm.

Preferably, the amount of Mg in the solid catalyst component is from 8 to 30 wt%, more preferably from 10 to 25 wt%.

Preferably, the amount of Ti is 0.1 to 8%, more preferably 0.5 to 5%, even more preferably 0.7 to 3% by weight.

The titanium atom preferably belongs to the titanium compound of formula Ti (OR2) nX4-n, wherein n is 0 to 4; x is halogen and R2 is a hydrocarbyl group, preferably an alkyl group, a group having 1 to 10 carbon atoms. Among these, particularly preferred are titanium compounds having at least one Ti-halogen bond, such as titanium tetrahalides or halogen alcoholates. Preferred specific titanium compounds are TiCl4 and Ti (OEt) Cl 3.

In a preferred aspect of the present disclosure, the catalyst component further comprises an electron donor compound (internal donor). Preferably, it is selected from esters, ethers, amines, silanes, carbamates and ketones or mixtures thereof.

When it is desired to increase the stereospecificity of the catalyst, the internal donor is preferably selected from the group consisting of alkyl and aryl esters of optionally substituted aromatic mono-or polycarboxylic acids, such as esters of benzoic and phthalic acid, and esters of aliphatic acids selected from malonic, glutaric, maleic and succinic acid. Specific examples of such esters are n-butyl phthalate, diisobutyl phthalate, di-n-octyl phthalate, ethyl benzoate and ethyl p-ethoxybenzoate. Also, diesters disclosed in WO2010/078494 and U.S. patent 7,388,061 may be used. Of this class, 2, 4-pentanediol dibenzoate derivatives and 3-methyl-5-tert-butylcatechol dibenzoate are particularly preferred. Furthermore, the internal donor may be selected from the group consisting of di-carbamates, mono-ester mono-carbamates and diol derivatives of mono-ester mono-carbonates. Furthermore, 1, 3-diethers of formula:

Wherein R, RI, RII, RIII, RIV and RV, equal to or different from each other, are hydrogen or a hydrocarbon radical having 1 to 18 carbon atoms and RVI and RVII, equal to or different from each other, have the same meaning of R-RV except that they cannot be hydrogen; one or more R-RVII groups may be attached to form a cycle. 1, 3-diethers in which RVI and RVII are chosen from C1-C4 alkyl groups are particularly preferred.

Mixtures of the above donors may also be used. A specific mixture is a mixture of esters of succinic acid and 1,3 diethers as disclosed in WO 2011/061134.

when it is desired to increase the ability of the catalyst to distribute the olefin comonomer within the polymer chain, for example in the case of the production of ethylene/alpha-olefin copolymers, it is preferred to select among the monofunctional donors an electron donor, in particular an ether or an ester. Preferred ethers are C2-C20 aliphatic ethers, in particular cyclic ethers, preferably having 3 to 5 carbon atoms, such as tetrahydrofuran, dioxane. Preferred esters are C1-C4 alkyl esters of aliphatic monocarboxylic acids, such as ethyl acetate and methyl formate. Tetrahydrofuran and ethyl acetate are most preferred.

In general, the final amount of electron donor compound in the solid catalyst component may be from 0.5 to 40% by weight, preferably from 1 to 35% by weight.

The preparation of the solid catalyst component can be carried out according to several methods. One method comprises the reaction between a magnesium alcoholate or a chlorohydrate (in particular a chlorohydrate prepared according to U.S. Pat. No. 4,220,554) and an excess of TiCl4 in the presence of an electron-donor compound at a temperature of about 80 to 120 ℃.

According to a preferred process, the solid catalyst component can be prepared by reaction of a titanium compound of formula Ti (OR2) m-yXy, where m is the valence of titanium, y is a number between 1 and m, R2 has the same meaning as previously specified, preferably TiCl4, wherein the magnesium chloride is derived from an adduct of formula MgCl2 · pR3OH, where p is a number from 0.1 to 6, preferably from 2 to 3.5, R3 is a hydrocarbon radical having from 1 to 18 carbon atoms. The spherical adduct can suitably be prepared by mixing the alcohol and the magnesium chloride in the presence of an inert hydrocarbon immiscible with the adduct, operating under stirring conditions at the melting temperature of the adduct (100-. The emulsion is then rapidly quenched, thereby solidifying the adduct in the form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP4,399,054 and USP4,469,648. The adduct thus obtained can be reacted directly with the Ti compound or can be previously subjected to a thermal controlled dealcoholation (at a temperature ranging from about 80 to 130 ℃) so as to obtain an adduct in which the number of moles of alcohol is lower than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or similar) in cold TiCl4 (ca. 0 ℃); the mixture is heated to 80-130 ℃ and held at this temperature for 0.5-2 hours. The treatment with TiCl4 may be carried out one or more times. The electron donor compound is preferably added during the treatment with TiCl 4. The preparation of spherical catalyst components is described, for example, in European patent applications EP-A-395083, EP-A-553805, EP-A-553806, EPA601525 and WIPO patent application publication No. WO 98/44009.

The catalyst mixture comprising particles made of the solid catalyst component (a) and particles made of compounds based on SiO2 units (b) can be prepared by several blending methods, the preferred method comprising dry mixing the two solids in a suitable apparatus. Preferably, the dry mixing is carried out at room temperature in a nitrogen atmosphere for 0.2 to 20 hours, preferably 0.5 to 15 hours, more preferably 0.5 to 5 hours.

It is also possible to prepare the mixture by stirring a liquid hydrocarbon slurry of particles (a) and (b) and subsequently removing the liquid phase and then drying the particles.

It can be seen from the examples that the catalyst mixtures thus obtained exhibit a reduced energy to break compared to the catalyst particles (a) themselves. This improvement is particularly significant when catalysts having a sphericity factor higher than 0.60 and preferably higher than 0.70 are used in combination. These catalysts also showed improved flowability in the avalanche energy and funnel test, demonstrating that improvements can be seen at various stages of catalyst handling. Further, the polymerization test conducted on the catalyst mixture confirmed that the performance was the same as that of the solid catalyst component containing no SiO2 unit-based compound.

The solid catalyst component according to the present disclosure is converted into a catalyst for olefin polymerization by reacting the solid catalyst component according to the present disclosure with an organoaluminum compound.

In particular, an object of the present disclosure is a catalyst for the polymerization of the olefin CH2 ═ CHR, wherein R is a hydrocarbon radical having from 1 to 12 carbon atoms, optionally in admixture with ethylene, comprising the product obtained by contacting:

(i) The solid catalyst component and

(ii) An alkyl aluminum compound, and

(iii) An external electron donor compound.

The alkylaluminum compound (ii) is preferably chosen among the trialkylaluminum compounds, such as triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum. It is also possible to use alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides, such as AlEt2Cl and Al2Et3Cl3, possibly mixed with the above-mentioned trialkylaluminums.

The Al/Ti ratio is higher than 1 and preferably between 50 and 2000.

Suitable external electron donor compounds include silicon compounds, ethers, esters, amines, heterocyclic compounds, in particular 2,2,6, 6-tetramethylpiperidine and ketones.

Another preferred class of external donor compounds are silicon compounds of formula (R6) a (R7) bSi (OR8) c, wherein a and b are integers from 0 to 2, c is an integer from 1 to 4, and the sum (a + b + c) is 4; r6, R7 and R8 are alkyl, cycloalkyl or aryl groups having 1 to 18 carbon atoms, optionally containing heteroatoms. Particularly preferred are silicon compounds wherein a is 1, b is 1, C is 2, at least one of R6 and R7 is selected from branched alkyl, cycloalkyl or aryl groups having 3 to 10 carbon atoms, optionally containing heteroatoms, and R8 is C1-C10 alkyl, especially methyl. Examples of such preferred silicon compounds are methylcyclohexyldimethoxysilane (C donor), diphenyldimethoxysilane, methyl-tert-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), diisopropyldimethoxysilane, (2-ethylpiperidinyl) tert-butyldimethoxysilane, (2-ethylpiperidinyl) tert-hexyldimethoxysilane, (3,3, 3-trifluoro-n-propyl) (2-ethylpiperidinyl) dimethoxysilane, methyl (3,3, 3-trifluoro-n-propyl) dimethoxysilane. Furthermore, silicon compounds in which a is 0, c is 3, R7 is a branched alkyl or cycloalkyl group, optionally containing heteroatoms, and R8 is methyl are also preferred. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, t-butyltrimethoxysilane and thexyltrimethoxysilane.

The electron donor compound (iii) is used in such an amount that the molar ratio between the organoaluminium compound and said electron donor compound (iii) is from 0.1 to 500, preferably from 1 to 300, more preferably from 3 to 100.

Therefore, another object of the present disclosure is a (co) polymerization process of olefins CH2 ═ CHR, wherein R is hydrogen or a hydrocarbon group having 1 to 12 carbon atoms, carried out in the presence of a catalyst, comprising the reaction product between:

(i) A solid catalyst component of the present disclosure;

(ii) An alkyl aluminum compound, and

(iii) An optional electron donor compound (external donor).

The polymerization process may be carried out according to various techniques, such as slurry polymerization using an inert hydrocarbon solvent as a diluent, or bulk polymerization using a liquid monomer (e.g., propylene) as a reaction medium. Furthermore, the polymerization process, which is operated in the gas phase, can be carried out in one or more fluidized or mechanically stirred bed reactors.

The polymerization can be carried out at a temperature of from 20 to 120 ℃, preferably from 40 to 80 ℃. When the polymerization is carried out in the gas phase, the operating pressure is from 0.5 to 5MPa, preferably from 1 to 4 MPa. In the bulk polymerization, the operating pressure may be from 1 to 8MPa, preferably from 1.5 to 5 MPa.

the following examples are given to better illustrate the invention without limiting it.