Chlorinated modified catalyst, its preparation method and application

Abstract

The present application belongs to the technical field of propylene polymerization catalysts, and particularly relates to a chlorinated modified catalyst and a preparation method and application thereof, and the chlorination modification method comprises the following steps: (1) contacting a propylene polymerization catalyst with a nucleating agent monomer and performing a reaction to obtain a pre-polymerization catalyst containing a polymer nucleating agent; (2) contacting the pre-polymerization catalyst containing the polymer nucleating agent with a chlorination reagent and performing a chlorination modification reaction to prepare the chlorinated modified catalyst; wherein the chlorination reagent is selected from one or more of (CH3)3SiCl, (CH3)2SiCl2, CH3SiCl3, SiCl4, C2H5AlCl2 and AlCl3. The obtained chlorinated modified catalyst is applied to propylene polymerization, which can reduce the fine powder content in the final polypropylene powder and narrow the particle size distribution of the polymer.

Description

Technical Field

[0001] This invention belongs to the technical field of propylene polymerization catalysts, and particularly relates to a chlorinated modified catalyst, its preparation method, and its application. Background Technology

[0002] Polypropylene is a highly crystalline semi-crystalline polymer, and its thermal, mechanical, and optical properties are closely related to its crystallinity. Nucleating agents are commonly used to modify the crystallization behavior of polypropylene to obtain higher crystallization temperatures, higher rigidity, and / or higher transparency. Inorganic salts, organic acid salts, sorbitan acetals, aromatic amides, and other compounds can all be used as polypropylene nucleating agents. The currently prevalent traditional method is to blend the nucleating agent with the polyolefin after the reaction. For example:

[0003] Nordic Chemicals' patent application WO9924478A1 discloses a method for adjusting the crystallization properties of polypropylene using a polymer nucleating agent. In this patent, a Ziegler-Natta catalyst is used to polymerize monomers such as vinylcyclohexane before propylene polymerization (prepolymerization stage) to obtain a catalyst containing a polymer nucleating agent. Propylene is then polymerized using this catalyst to obtain polypropylene containing the polymer nucleating agent. However, this patent application does not investigate the influence of prepolymerization conditions and other factors on the particle morphology of the catalyst containing the polymer nucleating agent, nor does it study the influence of the catalyst on the particle morphology of polypropylene. It only studies how the catalyst results in polypropylene with higher modulus and higher impact strength.

[0004] The operating steps and processes disclosed in LG's patent application CN101809043A are similar to those in patent application WO9924478A1, and neither mentions the influence of prepolymerization conditions on catalyst particle morphology or the influence of the catalyst on polypropylene particle morphology.

[0005] Basel's patent application CN103562233A only describes the prepolymerization stage of the nucleating agent precursor, without mentioning the influence of prepolymerization conditions on the morphology of catalyst particles or the influence of the catalyst on the morphology of polypropylene particles.

[0006] The aforementioned existing patent applications only provide methods for improving the properties of polyolefin (e.g., polypropylene) products by introducing nucleating agents into propylene polymerization catalysts during the prepolymerization stage. None of them mention the morphological characteristics of polypropylene particles and their impact, which are crucial for the operation of the polymerization unit.

[0007] The modification of propylene polymerization catalysts with nucleating agents can be carried out by the method described in patent application WO9924478A1, which uses bulk slurry polymerization in a 2-liter reactor, but the morphology of the resulting product powder is not clearly defined. In the same patent document, a pilot plant with a prepolymer reactor is also used to produce polypropylene, but the morphological characteristics of the polypropylene powder are also not clearly defined.

[0008] Patent document EP2718335A1 discloses a prepolymer catalyst component for olefin polymerization. It mentions that during the preparation of this prepolymer catalyst component by nucleating agent monomers such as vinylcyclohexane, agglomeration occurs due to vinylcyclohexane polymerization. Moreover, the resulting prepolymer catalyst is designed to exhibit an excellent balance in terms of activity, morphological stability, reduced agglomeration tendency, and hydrogen reaction.

[0009] However, for prepolymerization catalysts containing polymer nucleating agents prepared by existing technologies, the prepolymerized catalyst particles contain polymers with high glass transition temperatures, thus altering their mechanical properties. The particles are prone to breakage during growth or under external forces during subsequent reactions. Furthermore, because the catalyst is activated during the prepolymerization stage, its growth kinetics during olefin polymerization are altered, resulting in high initial activity, which also contributes to particle breakage. Both of these factors are detrimental to maintaining the morphology of the catalyst / polymer particles, easily leading to the generation of fine powder in the desired product, which is detrimental to the operation of the polymerization unit. Summary of the Invention

[0010] The purpose of this invention is to address the problems existing in the prior art by providing a chlorinated catalyst, its preparation method, and its application. By treating the catalyst containing polymer nucleating agents with a chlorinating agent, the content of fine powder in the final polypropylene powder can be reduced, and the particle size distribution can be narrowed.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] In a first aspect, a chlorinated catalyst is provided, which is a chlorinated Ziegler-Natta catalyst containing a polymer nucleating agent, wherein the polymer nucleating agent is selected from one or more of poly(vinylcyclohexane), poly(vinylcyclopentane), poly(styrene), and poly(allyltrimethylsilane).

[0013] The catalyst comprises magnesium, titanium, chlorine, and an internal electron donor;

[0014] The internal electron donor is selected from one or more of the following: benzoic acid esters, phthalic acid esters, 1,3-diethers, succinic acid esters, maleic acid esters, malonic acid esters, 1,3-diol esters, 2,4-diol esters, o-diphenol esters, 1,8-naphthol esters, cycloalkyl o-diphenol esters, and amide esters.

[0015] The catalyst contains the following components that meet the following requirements:

[0016] 2≥[Cl] / (4*[Ti]+2*[Mg])≥1.02; for example, 1.1, 1.3, 1.5, 1.8;

[0017] Wherein, [Cl] is the total molar amount of Cl in the catalyst slurry, [Ti] is the molar amount of Ti in the catalyst slurry, and [Mg] is the molar amount of Mg in the catalyst slurry.

[0018] In a second aspect, a method for chlorinating a prepolymer catalyst containing a polymer nucleating agent is provided, comprising the following steps:

[0019] (1) The propylene polymerization catalyst is contacted with the nucleating agent monomer and reacted to obtain a prepolymerization catalyst containing a polymer nucleating agent;

[0020] (2) The prepolymer catalyst containing the polymer nucleating agent obtained in step (1) is contacted with a chlorinating agent and subjected to a chlorination modification reaction to obtain a chlorinated catalyst; wherein,

[0021] The propylene polymerization catalyst is a Ziegler-Natta catalyst or a metallocene catalyst;

[0022] The chlorinating agent is a compound containing active chlorine, represented by the following general chemical formula I or formula II:

[0023] R 6 x MCl 4-x , Formula I

[0024] In the formula, M is Si or Sn; x is a natural number and x < 4 (e.g., 1, 2, 3);

[0025] R 7 y ACl 3-y Formula II

[0026] In the formula, A is B (boron), Al, or Ga; y is a natural number and y < 3 (e.g., 1, 2); R 6 R 7 Each is independently selected from C1-C 12Straight-chain, branched, or cyclic aliphatic hydrocarbon groups.

[0027] In this document, the aliphatic hydrocarbon groups involved may be, for example, but not limited to, alkyl (methyl, ethyl, n-propyl, n-butyl, isobutyl, pentyl, hexyl) and cycloalkyl.

[0028] In some embodiments of the chlorination treatment method provided by the present invention, the chlorinating agent is selected from one or more of (CH3)3SiCl, (CH3)2SiCl2, CH3SiCl3, SiCl4, C2H5AlCl2 and AlCl3.

[0029] In this article, polymer nucleating agent refers to the polymer obtained by polymerizing nucleating agent monomers with olefin (such as propylene) polymerization catalysts. The polymer nucleating agent contained in the prepolymerization catalyst prepared in step (1) is generated by the conversion of nucleating agent monomers through a polymerization reaction, and it can be considered that there is no mass loss during the conversion process. Therefore, under the premise of ensuring that its conversion rate is higher than 95%, the amount of nucleating agent monomer added can be determined according to the corresponding ratio calculated by the raw material conversion rate theory.

[0030] The prepolymerization catalyst containing the polymer nucleating agent obtained in step (1) may comprise two components: the polymer nucleating agent and the unmodified propylene polymerization catalyst. In some embodiments, the mass ratio of the polymer nucleating agent to the unmodified propylene polymerization catalyst in the prepolymerization catalyst containing the polymer nucleating agent in step (1) is 0.1 to 10:1 (e.g., 0.15:1, 0.2:1, 0.4:1, 0.8:1, 1:1, 2:1, 4:1, 6:1, 8:1), preferably 0.1 to 5:1, and more preferably 0.5 to 5:1.

[0031] Typically, if the prepolymer catalyst containing the polymer nucleating agent is selected to be obtained by polymerization reaction of Ziegler-Natta catalyst and nucleating agent monomer, the mass ratio of the polymer nucleating agent to the precatalyst contained in the unmodified Ziegler-Natta catalyst can be limited to 0.1 to 10:1 (e.g., 0.15:1, 0.2:1, 0.4:1, 0.8:1, 1:1, 2:1, 4:1, 6:1, 8:1).

[0032] In step (1), for example, the nucleating agent monomer can be added to the system in steps for reaction; the total reaction time for each step is 1-72 hours (e.g., 2 hours, 4 hours, 6 hours, 8 hours, 12 hours, 18 hours, 24 hours, 30 hours, 36 hours, 42 hours, 50 hours, 60 hours, 70 hours). For example, the nucleating agent monomer is added in two steps: the propylene polymerization catalyst is contacted with a portion of the nucleating agent monomer for reaction, and the reaction time is 0.5-48 hours (e.g., 1 hour, 4 hours, 6 hours, 8 hours, 12 hours, 18 hours, 24 hours, 28 hours, 30 hours, 32 hours, 40 hours); then the remaining portion of the nucleating agent monomer is added to the system and the reaction continues for 0.5-48 hours (e.g., 1 hour, 4 hours, 6 hours, 8 hours, 12 hours, 18 hours, 24 hours, 28 hours, 30 hours, 32 hours, 40 hours). For example, when the nucleating agent monomer is added in two steps, the molar ratio of the nucleating agent monomer added in the first step to that added in the second step is 1:1.

[0033] In some embodiments, in step (2), the ratio of the chlorinating agent to the prepolymerization catalyst containing the polymer nucleating agent is calculated based on the molar ratio of the chlorinating agent to aluminum in the propylene polymerization catalyst (e.g., aluminum introduced through a co-catalyst contained in the propylene polymerization catalyst before modification). The molar ratio of the chlorinating agent to aluminum in the propylene polymerization catalyst is 0.1 to 10:1 (e.g., 0.15:1, 0.2:1, 0.4:1, 0.8:1, 1:1, 2:1, 4:1, 6:1, 8:1), preferably 0.5 to 5:1. For example, if the selected chlorinating agent contains silicon, the ratio of the chlorinating agent to the propylene polymerization catalyst can be calculated using the silicon-aluminum molar ratio.

[0034] According to the chlorination treatment method provided by the present invention, in some embodiments, the nucleating agent monomer is a compound represented by general formula III:

[0035]

[0036] In the formula, R 1 and R 2 Together with the carbon atoms to which they are attached, they form optionally substituted saturated or unsaturated or aromatic cyclic or fused-ring systems, wherein the cyclic or fused-ring portion contains 4 to 20 carbon atoms, preferably 5 to 12-membered saturated or unsaturated or aromatic cyclic or fused-ring systems, or R 1 and R 2 Each is independently an alkyl group containing 1 to 4 carbon atoms, or R 1 and R 2 Each is an alkyl group containing 0 to 4 carbon atoms and substituted with silicon atoms.

[0037] In some embodiments, the nucleating agent monomer is selected from one or more of vinylcycloalkane, 3-methyl-1-butene, 3-ethyl-1-hexene, styrene, p-methylstyrene, and allyltrimethylsilane; the vinylcycloalkane is preferably selected from vinylcyclohexane, vinylcyclopentane, vinyl-2-methylcyclohexane, or vinylnorbornene.

[0038] The nucleating agent monomer is preferably selected from one or more of vinylcyclohexane, vinylcyclopentane, styrene, and allyltrimethylsilane.

[0039] According to the chlorination treatment method provided by the present invention, in some embodiments, the Ziegler-Natta catalyst includes a pre-catalyst, a co-catalyst i, and an optional external electron donor;

[0040] The pre-catalyst comprises magnesium, titanium, chlorine, and an internal electron donor;

[0041] The internal electron donor is selected from one or more of the following: benzoic acid esters, phthalic acid esters, 1,3-diethers, succinic acid esters, maleic acid esters, malonic acid esters, 1,3-diol esters, 2,4-diol esters, o-diphenol esters, 1,8-naphthol esters, cycloalkyl o-diphenol esters, and amide esters; the internal electron donor may be, for example, but not limited to, ethyl benzoate, ethyl p-ethoxybenzoate, di-n-butyl phthalate, diisobutyl phthalate, and 2,2-diisopropyl phthalate. 2,2-Diisobutyl-1,3-dimethoxypropane, 2,2-Dicyclopentyl-1,3-dimethoxypropane, 2-Ethyl-2-butyl-1,3-dimethoxypropane, 2-Isopropyl-2-isopentyl-1,3-dimethoxypropane, 9,9-Di(methoxymethyl)fluorene, Diethyl 2,3-diisopropylsuccinate, Di-n-butyl 2,3-diisopropylsuccinate, Diisobutyl 2,3-diisopropylsuccinate, Di(2-ethylhexyl)citric acid ester, Dimethyl benzenemethylene malonate, Diethyl benzenemethylene malonate, 2,4-Pentanediol Benzoate, 1,3-propanediol dibenzoate, 3-methyl-2,4-pentanediol dibenzoate, 3-methyl-5-tert-butyl-1,2-benzenediol dibenzoate, 4-tert-butyl-1,2-benzenediol dibenzoate, 3,6-dimethyl-1,2-benzenediol dibenzoate, 1,8-naphthyldiphenol dibenzoate, 2,4-pentanediol di(4-methylbenzoic acid) ester, 1,3-propanediol di(4-methylbenzoic acid) ester, 3-methyl-2,4-pentanediol di(4-methylbenzoic acid) ester, 3-methyl-5-tert-butyl-1,2-benzenediol di(4-methylbenzoic acid) ester The following are some of the following: 4-tert-butyl-1,2-benzenediol di(4-methylbenzoic acid) ester, 3,6-dimethyl-1,2-benzenediol di(4-methylbenzoic acid) ester, 1,8-naphthol di(4-methylbenzoic acid) ester, 1,2-cyclohexanediol diisobutyl ester, 1,2,3,6-tetrahydrophthalic acid diethyl ester, N-(3-benzylcarboxyl-1-methylbutyl)benzamide, N-[2-benzylcarboxyl-4-tert-butyl-6-methylphenyl]benzamide, and N-[3-(4-butylbenzylcarboxyl)-2,2-dimethylpropyl]-4-butylbenzamide;

[0042] The cocatalyst i is a hydrocarbon-based aluminum compound, preferably selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum and trihexylaluminum, and more preferably trialkylaluminum.

[0043] In some implementations, the external electron donor is of general formula R. 3 m R 4 n Si(OR5 ) 4-m-n The organosilicon compound shown has the following formula: R 3 R 4 Each group is independently selected from C1-C12 straight-chain, branched, or cyclic aliphatic groups, or C3-C12 nitrogen-containing straight-chain, branched, or cyclic organic groups; R 5 Selected from C1-C4 straight-chain or branched aliphatic groups; m and n are natural numbers, and their values ​​satisfy 0 ≤ (m + n) ≤ 2; the external electron donor may be, for example, but not limited to, dimethyldimethoxysilane, diphenyldimethoxysilane, methylcyclopentyldimethoxysilane, methylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, di-n-propyldimethoxysilane, di-n-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isopropylisopentyldimethoxysilane, methylcyclopentyldiethoxysilane, methylcyclohexyldiethoxysilane, dicyclopentyldiethoxysilane, dicyclohexyldiethoxysilane, di-n-propyldiethoxysilane, di-n-butyldiethoxysilane. Diisopropyldiethoxysilane, diisobutyldiethoxysilane, isopropylisopentyldiethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isopentyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, allyltrimethoxysilane, vinyltrimethoxysilane, diethylaminotrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isobutyltriethoxysilane, isopentyltriethoxysilane, cyclopentyltriethoxysilane, cyclohexyltriethoxysilane, allyltriethoxysilane, vinyltriethoxysilane, diethylaminotriethoxysilane, tetramethoxysilane, and tetraethoxysilane are all of the following:

[0044] According to the chlorination method provided by the present invention, in some embodiments, the metallocene catalyst includes a support, a metallocene coordination compound, and a co-catalyst; wherein:

[0045] The carrier is selected from particulate silica or layered silicate;

[0046] The metallocene coordination compound is selected from bridged C2-symmetrical compounds containing a group IV metal and an indene group, such as, but not limited to, one or more of rac-dimethylsilyl-bis(2-methyl-4-phenylindene)zirconia, rac-dimethylsilyl-bis(2-methyl-4,5-benzylindene)zirconia, rac-dimethylsilyl-bis(2-methyl-4-carbazolylindene)zirconia and rac-dimethylsilyl-bis[2-methyl-4-(3,5-di-tert-butylphenyl)-7-methoxyindene]zirconia;

[0047] The co-catalyst ii is selected from methylaluminoxane or modified methylaluminoxane.

[0048] The chlorinated catalyst was prepared by the chlorination treatment method described above.

[0049] In some embodiments, the propylene polymerization catalyst used before modification is a Ziegler-Natta catalyst. Therefore, the catalyst prepared by the chlorination treatment method is a chlorinated Ziegler-Natta catalyst containing a polymer nucleating agent, comprising a polymer nucleating agent component, an internal electron donor, and components such as chlorine, titanium, and magnesium. The components contained therein meet the following requirements:

[0050] 2≥[Cl] / (4*[Ti]+2*[Mg])≥1.02;

[0051] Wherein, [Cl] is the total molar amount of Cl in the catalyst slurry, [Ti] is the molar amount of Ti in the catalyst slurry, and [Mg] is the molar amount of Mg in the catalyst slurry.

[0052] In some embodiments, the propylene polymerization catalyst used before modification is a metallocene catalyst. Therefore, the catalyst prepared by the chlorination treatment method is a chlorinated modified metallocene catalyst containing a polymer nucleating agent, comprising a polymer nucleating agent component and components such as chlorine and zirconium. The components contained therein meet the following requirements:

[0053] 200≥[Cl] / (2*[Zr]≥2.04; for example, 3, 5, 10, 50, 80, 100, 120, 180;

[0054] Where [Cl] is the total molar amount of Cl in the catalyst slurry, and [Zr] is the molar amount of Zr in the catalyst slurry.

[0055] In a third aspect, the application of the catalyst as described above or the chlorinated catalyst obtained by the chlorination treatment method as described above in propylene polymerization is provided, comprising the following steps:

[0056] In the presence of the chlorinated catalyst, co-catalyst, and optional external electron donor, propylene monomer or propylene is polymerized with one or more other olefins to produce polypropylene; wherein the polymerization temperature is 50 to 120°C (e.g., 60°C, 70°C, 80°C, 90°C, 100°C, 110°C), and the polymerization pressure is 0.1 to 5 MPa (e.g., 0.2 MPa, 0.5 MPa, 1.0 MPa, 2.0 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa);

[0057] The cocatalyst is a hydrocarbon-based aluminum compound (e.g., one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, and trihexylaluminum), and the external electron donor is of general formula R. 3 m R 4 n Si(OR 5 ) 4-m-n The organosilicon compound shown has the following formula: R 3 R 4 Each group is independently selected from C1-C12 straight-chain, branched, or cyclic aliphatic groups, or C3-C12 nitrogen-containing straight-chain, branched, or cyclic organic groups; R 5 Selected from C1-C4 straight-chain or branched aliphatic groups; m and n are natural numbers, and their values ​​satisfy 0≤(m+n)≤2.

[0058] According to the application provided by the present invention, in some embodiments, the amount of the chlorinated modified catalyst added in the resulting polypropylene ranges from 1 to 500 ppm by mass (e.g., 10 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm).

[0059] According to the application provided by the present invention, polypropylene is produced under typical propylene polymerization experimental conditions known in the art. Typically, if the chlorinated catalyst is obtained by polymerization of nucleating agent monomers using a selected Ziegler-Natta catalyst followed by chlorination modification, the ratio of the chlorinated catalyst, co-catalyst, and optional external electron donor in the propylene polymerization system is calculated based on the molar ratio of aluminum in the co-catalyst to titanium in the chlorinated catalyst, with an aluminum-titanium molar ratio of 1:1 to 300:1 (e.g., 2:1, 10:1, 50:1, 100:1, 120:1, 155:1, 160:1, 1...). The ratios are 70:1, 180:1, 200:1, 220:1, 240:1, 260:1, 280:1, 290:1), more preferably 10:1 to 200:1; the aluminum-silicon molar ratio is 1:1 to 20:1 (e.g., 2:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1), more preferably 3:1 to 6:1, calculated based on the molar ratio of aluminum in the co-catalyst to silicon in the external electron donor.

[0060] According to the application provided by the present invention, in some embodiments, the chlorinated catalyst is pre-contacted with a co-catalyst and an optional external electron donor before being added to the polymerization system for a pre-contact time of 5-60 min (e.g., 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min); then the material containing the chlorinated catalyst, co-catalyst and optional external electron donor obtained after pre-contact is added to the polymerization system.

[0061] Alternatively, in some embodiments, the chlorinated catalyst is not pre-contacted with the co-catalyst and optional external electron donor before being added to the polymerization system, and the chlorinated catalyst, co-catalyst and optional external electron donor are added to the polymerization system separately.

[0062] In this text, the prepolymerization catalyst containing the polymer nucleating agent, the cocatalyst, and the optional external electron donor (via the feed line) are added to the polymerization reactor separately without pre-contact. This can be understood as follows: if no external electron donor is used, the prepolymerization catalyst containing the polymer nucleating agent and the cocatalyst are added to the polymerization reactor separately via their respective feed lines; if an external electron donor is optionally used, the mixture of the cocatalyst and the external electron donor, and the prepolymerization catalyst containing the polymer nucleating agent are added to the polymerization reactor separately via their respective feed lines; or the prepolymerization catalyst containing the polymer nucleating agent, the cocatalyst, and the external electron donor are added to the polymerization reactor separately via their respective feed lines.

[0063] In this article, the terms "propylene polymerization catalyst containing (polymer) nucleating agent" and "prepolymerization catalyst containing polymer nucleating agent" refer to the same thing.

[0064] In this invention, pre-contact refers to the prepolymerization catalyst containing the polymer nucleating agent being pre-contacted or mixed with a cocatalyst or a mixture of the cocatalyst and an external electron donor before contacting the propylene monomer, for example, a contact time of 5-60 minutes.

[0065] The reaction apparatus used for propylene polymerization mentioned in this invention is well known to those skilled in the art and will not be described in detail here.

[0066] In this invention, the fine powder refers to polymer powder particles with a particle size of less than 150 μm. These particles have a powdery appearance and are easily adsorbed onto the inner wall of the reactor due to electrostatic attraction.

[0067] The main advantages of the chlorinated modified catalyst prepared by this invention are: when applied to propylene polymerization, it reduces the content of fine powder in the resulting polypropylene and narrows the particle size distribution of polypropylene. By chlorinating the propylene polymerization catalyst containing a polymer nucleating agent, the activated and prepolymerized prepolymer catalyst containing the polymer nucleating agent can stop further reaction or slow down its further reaction, thereby maintaining the catalyst particle morphology. This, in turn, maintains the morphology of the catalyst particles / polymer particles obtained from subsequent polymerization, ultimately reducing or avoiding the generation of fine powder in the polypropylene product.

[0068] Using the chlorinated modified catalyst of this invention to produce polypropylene can yield a polypropylene product with good morphology and few fine powders, and the product has superior mechanical and optical properties. Detailed Implementation

[0069] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments of the invention are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0070] <Source of Raw Materials>

[0071] In all the embodiments and comparative examples, the propylene polymerization catalysts used in the reaction with the nucleating agent monomers contained the precatalysts, which were commercially available from Lihe Technology Development Co., Ltd.: SUG slurry catalyst (with a titanium content of 7.25 mg / mL as measured by ICP-AES and a solid catalyst content of approximately 0.26 g / mL) and SAL dry powder catalyst (with a titanium content of 2.78 wt% as measured by ICP-AES).

[0072] In this invention, the improvement in particle morphology of the product refers to the narrowing of the particle size distribution, that is, the parameter used to measure the particle size distribution becomes smaller.

[0073] In this invention, there are two parameters for measuring particle size distribution, namely D1 and D2:

[0074] D1=(d90-d10) / d50

[0075] In the above formula, d10, d50, and d90 are the particle sizes corresponding to the ordinate values ​​of the integral curve at 10%, 50%, and 90%, respectively, obtained by normalizing and integrating the area under the particle size distribution curve.

[0076] D2=dv / dn

[0077] In the formula, dv is the particle size after weighting all particles by volume, and dn is the particle size after weighting all particles by number.

[0078] <Testing Methods>

[0079] The particle size distribution of polypropylene powder was measured using a Microtrac S3500 laser particle size analyzer, which directly yielded the parameters d10, d50, d90, dv, and dn mentioned above.

[0080] Example 1

[0081] A chlorination treatment method for a prepolymerization catalyst containing a polymer nucleating agent includes the following steps:

[0082] (1) Disperse 1 mL of well-shaken SUG slurry catalyst in 5 mL of mineral oil, and slowly inject 1 mol / L of triisobutylaluminum n-hexane solution according to an aluminum-titanium molar ratio of 1.5. Then slowly add 0.5 g of vinylcyclohexane (VCH) and carry out the prepolymerization reaction at normal pressure and room temperature for 24 hours. Then add another 0.5 g of vinylcyclohexane and continue the reaction for 24 hours to obtain a prepolymerization catalyst containing a polymer nucleating agent.

[0083] (2) Add SiCl4 to the system, the amount of which is calculated according to the silicon-aluminum molar ratio between silicon in SiCl4 and aluminum introduced by triisobutylaluminum in the obtained catalyst being 1:1; perform chlorination modification reaction on the prepolymer catalyst containing polymer nucleating agent to obtain the chlorinated modified catalyst.

[0084] The chlorinated modified catalyst obtained above is applied to the propylene polymerization system:

[0085] Add 1L of liquid propylene to a 2L stainless steel reactor, introduce 0.1MPa hydrogen gas, and heat to 70℃; add a freshly prepared triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the stainless steel reactor.

[0086] Take 0.1 mL of the chlorinated catalyst slurry obtained above after shaking and mix it with 10 mL of n-hexane and transfer it to a feeding tank for later use; then, inject the slurry containing the chlorinated catalyst prepared in the feeding tank into a stainless steel reactor using high-pressure hexane to initiate the polymerization reaction, which lasts for 30 minutes; wherein,

[0087] The ratio of the triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the chlorinated catalyst is calculated based on a molar ratio of aluminum in triethylaluminum to titanium in the chlorinated catalyst of 200:1, and a molar ratio of aluminum to silicon in triethylaluminum / dicyclopentyldimethoxysilane of 5:1.

[0088] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of chlorinated modified catalyst in the obtained polypropylene was approximately 131 ppm by mass. The results of the tests are shown in Table 1.

[0089] Comparative Example 1

[0090] The preparation process of the prepolymer catalyst containing the polymer nucleating agent is the same as step (1) of Example 1, but without the chlorination treatment of step (2) of the prepolymer catalyst containing the polymer nucleating agent.

[0091] The prepolymerization catalyst containing the polymer nucleating agent obtained above is applied to the propylene polymerization system:

[0092] Add 1L of liquid propylene to a 2L stainless steel reactor, introduce 0.1MPa hydrogen gas, and heat to 70℃; add a freshly prepared triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the stainless steel reactor.

[0093] Take 0.1 mL of the prepolymer catalyst slurry containing the polymer nucleating agent obtained above after shaking, mix it with 10 mL of n-hexane, and transfer it to a feeding tank for later use; then, inject the prepared prepolymer catalyst slurry containing the polymer nucleating agent from the feeding tank into a stainless steel reactor using high-pressure hexane to initiate the polymerization reaction, which lasts for 30 minutes; wherein...

[0094] The ratio of the triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the prepolymerization catalyst containing the polymer nucleating agent is calculated based on a molar ratio of aluminum in triethylaluminum to titanium in the prepolymerization catalyst containing the polymer nucleating agent of 200:1, and a molar ratio of aluminum to silicon in triethylaluminum / dicyclopentyldimethoxysilane of 5:1.

[0095] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of the prepolymer catalyst containing the polymer nucleating agent in the obtained polypropylene was approximately 108 ppm by mass. Tests were performed, and the results are shown in Table 1.

[0096] Example 2

[0097] A chlorination treatment method for a prepolymerization catalyst containing a polymer nucleating agent includes the following steps:

[0098] (1) Disperse 0.24g of SAL dry powder catalyst in 6mL of mineral oil, and slowly inject 1mol / L of triisobutylaluminum n-hexane solution according to the aluminum-titanium molar ratio of 1.5. Then slowly add 0.24g of vinylcyclohexane (VCH) and carry out prepolymerization reaction at normal pressure and room temperature for 72 hours to obtain a prepolymerization catalyst containing polymer nucleating agent.

[0099] (2) Add SiCl4 to the system, the amount of which is calculated according to the silicon-aluminum molar ratio between silicon in SiCl4 and aluminum introduced by triisobutylaluminum in the obtained catalyst being 1:1; perform chlorination modification reaction on the prepolymer catalyst containing polymer nucleating agent to obtain the chlorinated modified catalyst.

[0100] The chlorinated modified catalyst obtained above is applied to the propylene polymerization system:

[0101] Add 2L of liquid propylene to a 5L stainless steel reactor, introduce 0.1MPa hydrogen gas, and heat to 70℃; add a freshly prepared triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the stainless steel reactor.

[0102] Take 0.2 mL of the chlorinated catalyst slurry obtained above after shaking and mix it with 10 mL of n-hexane and transfer it to a feeding tank for later use; then, inject the slurry containing the chlorinated catalyst prepared in the feeding tank into a stainless steel reactor using high-pressure hexane to initiate the polymerization reaction, which lasts for 60 minutes; wherein,

[0103] The ratio of the triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the chlorinated catalyst is calculated based on a molar ratio of aluminum in triethylaluminum to titanium in the chlorinated catalyst of 200:1, and a molar ratio of aluminum to silicon in triethylaluminum / dicyclopentyldimethoxysilane of 5:1.

[0104] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of chlorinated modified catalyst in the obtained polypropylene was approximately 55 ppm by mass. Tests were performed, and the results are shown in Table 1.

[0105] Example 3

[0106] A chlorination treatment method for a prepolymerization catalyst containing a polymer nucleating agent includes the following steps:

[0107] (1) 0.24 g of SAL dry powder catalyst was dispersed in 6 mL of mineral oil and slowly injected into a 1 mol / L triisobutylaluminum n-hexane solution at an aluminum-titanium molar ratio of 1.5. Then, 0.5 g of vinylcyclohexane (VCH) was slowly added and the prepolymerization reaction was carried out at room temperature and atmospheric pressure for 24 hours. After that, another 0.5 g of vinylcyclohexane was added and the reaction was continued for 48 hours to obtain a prepolymerization catalyst containing a polymer nucleating agent.

[0108] (2) Add EtAlCl2 to the system, the amount of which is calculated according to the molar ratio between aluminum in EtAlCl2 and aluminum introduced by triisobutylaluminum in the obtained catalyst being 1:1; perform chlorination modification reaction on the prepolymer catalyst containing polymer nucleating agent to obtain the chlorinated modified catalyst.

[0109] The chlorinated modified catalyst obtained above is applied to the propylene polymerization system:

[0110] Add 2L of liquid propylene to a 5L stainless steel reactor, introduce 0.1MPa hydrogen gas, and heat to 70℃; add a freshly prepared triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the stainless steel reactor.

[0111] Take 0.2 mL of the chlorinated catalyst slurry obtained above after shaking and mix it with 10 mL of n-hexane and transfer it to a feeding tank for later use; then, inject the slurry containing the chlorinated catalyst prepared in the feeding tank into a stainless steel reactor using high-pressure hexane to initiate the polymerization reaction, which lasts for 60 minutes; wherein,

[0112] The ratio of the triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the chlorinated catalyst is calculated based on a molar ratio of aluminum in triethylaluminum to titanium in the chlorinated catalyst of 200:1, and a molar ratio of aluminum to silicon in triethylaluminum / dicyclopentyldimethoxysilane of 5:1.

[0113] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of chlorinated modified catalyst in the obtained polypropylene was approximately 209 ppm by mass. The results of the tests are shown in Table 1.

[0114] Comparative Example 2

[0115] The preparation process of the prepolymer catalyst containing the polymer nucleating agent is the same as step (1) of Example 3, but the prepolymer catalyst containing the polymer nucleating agent is not subjected to the chlorination treatment in step (2).

[0116] The prepolymerization catalyst containing the polymer nucleating agent obtained above is applied to the propylene polymerization system:

[0117] The operation steps are the same as in Example 3.

[0118] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of the prepolymer catalyst containing the polymer nucleating agent in the obtained polypropylene was approximately 292 ppm by mass. Tests were performed, and the results are shown in Table 1.

[0119] Example 4

[0120] A chlorination treatment method for a prepolymerization catalyst containing a polymer nucleating agent includes the following steps:

[0121] (1) The preparation process of the prepolymerization catalyst containing the polymer nucleating agent is as described in Example 1;

[0122] (2) The chlorination process of the prepolymer catalyst containing the polymer nucleating agent is as described in Example 1; the chlorinated modified catalyst is obtained.

[0123] The chlorinated modified catalyst obtained above is applied to the propylene polymerization system:

[0124] Take 0.1 mL of the well-shaken chlorinated modified catalyst slurry and pre-contact it with the freshly prepared triethylaluminum / dicyclopentyldimethoxysilane mixed solution in the feeding tank for 5 minutes; wherein, the ratio of the triethylaluminum / dicyclopentyldimethoxysilane mixed solution to the chlorinated modified catalyst is based on a molar ratio of aluminum in triethylaluminum to titanium in the chlorinated modified catalyst of 200:1, and a molar ratio of aluminum to silicon in triethylaluminum / dicyclopentyldimethoxysilane of 5:1.

[0125] 1L of liquid propylene and 0.1MPa hydrogen were added to a 2L stainless steel reactor and the temperature was raised to 70°C. The slurry containing the chlorinated modified catalyst and triethylaluminum / dicyclopentyldimethoxysilane, which had been pre-contacted in the above feed tank, was injected into the stainless steel reactor using high-pressure hexane to initiate the polymerization reaction, which lasted for 30 minutes.

[0126] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of chlorinated modified catalyst in the obtained polypropylene was approximately 98 ppm by mass. Tests were performed, and the results are shown in Table 1.

[0127] Comparative Example 3

[0128] The preparation process of the prepolymer catalyst containing the polymer nucleating agent is the same as step (1) of Example 4, but without the chlorination treatment of step (2) of the prepolymer catalyst containing the polymer nucleating agent.

[0129] The prepolymerization catalyst containing the polymer nucleating agent obtained above is applied to the propylene polymerization system:

[0130] The operation steps are the same as in Example 4.

[0131] After the reaction was complete, the material in the reactor was discharged into a receiving tank to obtain polypropylene product. The amount of the prepolymer catalyst containing the polymer nucleating agent in the obtained polypropylene was approximately 87 ppm by mass. Tests were performed, and the results are shown in Table 1.

[0132] Table 1

[0133]

[0134] As can be seen from the test results shown in Table 1, compared with the comparative example, the particle size distribution parameters D1 and D2 of the polypropylene powder obtained using the chlorinated catalyst in each embodiment of this application are generally reduced, and the content of fine powder with a particle size of less than 150 μm is very low. This indicates that the particle size distribution of the polypropylene product obtained in this application is narrowed, and the content of fine powder is significantly reduced.

[0135] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.

Claims

1. A method for chlorinating a prepolymer catalyst containing a polymer nucleating agent, characterized in that, Includes the following steps: (1) The propylene polymerization catalyst is contacted with the nucleating agent monomer and reacted to obtain a prepolymerization catalyst containing a polymer nucleating agent; (2) The prepolymer catalyst containing polymer nucleating agent obtained in step (1) is contacted with chlorinating agent and subjected to chlorination modification reaction to obtain chlorinated modified catalyst; the ratio of chlorinating agent to prepolymer catalyst containing polymer nucleating agent is calculated based on the molar ratio of chlorinating agent to aluminum in propylene polymerization catalyst, and the molar ratio of chlorinating agent to aluminum in propylene polymerization catalyst is 0.5 to 5:

1. in, The propylene polymerization catalyst is a Ziegler-Natta catalyst or a metallocene catalyst; The chlorinating agent is a compound containing active chlorine, represented by the following general chemical formula I or formula II: R 6 x MCl 4-x , formula I In the formula, M is Si or Sn; x is a natural number and x < 4; R 7 y ACl 3-y , formula II In the formula, A is B, Al, or Ga; y is a natural number and y < 3. R 6 R 7 Each is independently selected from C1-C 12 Straight-chain, branched, or cyclic aliphatic hydrocarbon groups; The nucleating agent monomer is a compound represented by general formula III: In the formula, R 1 and R 2 Together with the carbon atoms they are attached to, they form optionally substituted saturated or unsaturated or aromatic cyclic or fused-ring systems, wherein the cyclic or fused-ring portion contains 4 to 20 carbon atoms, or R 1 and R 2 Each is independently an alkyl group containing 1 to 4 carbon atoms; and / or, The nucleating agent monomer is allyltrimethylsilane.

2. The chlorination treatment method according to claim 1, characterized in that, The chlorinating agent is selected from one or more of (CH3)3SiCl, (CH3)2SiCl2, CH3SiCl3, SiCl4, C2H5AlCl2, and AlCl3.

3. The chlorination treatment method according to claim 1, characterized in that, In general formula III, R 1 and R 2 Together with the carbon atoms to which they are attached, they form optionally substituted saturated or unsaturated or aromatic cyclic or fused-ring systems, wherein the cyclic or fused-ring portion is a 5- to 12-membered saturated or unsaturated or aromatic cyclic or fused-ring system, or R 1 and R 2 Each is an alkyl group containing 1 to 4 carbon atoms.

4. The chlorination treatment method according to claim 1, characterized in that, The nucleating agent monomer is selected from one or more of vinylcycloalkanes, 3-methyl-1-butene, 3-ethyl-1-hexene, styrene, p-methylstyrene, and allyltrimethylsilane.

5. The chlorination treatment method according to claim 4, characterized in that, The vinylcycloalkane is selected from vinylcyclohexane, vinylcyclopentane, vinyl-2-methylcyclohexane, or vinylnorbornene.

6. The chlorination treatment method according to claim 1, characterized in that, The nucleating agent monomer is selected from one or more of vinylcyclohexane, vinylcyclopentane, styrene, and allyltrimethylsilane.

7. The chlorination treatment method according to claim 1, characterized in that, The Ziegler-Natta catalyst includes a pre-catalyst, a co-catalyst i, and an optional external electron donor; The pre-catalyst comprises magnesium, titanium, chlorine, and an internal electron donor; The internal electron donor is selected from one or more of the following: benzoic acid esters, phthalic acid esters, 1,3-diethers, succinic acid esters, maleic acid esters, malonic acid esters, 1,3-diol esters, 2,4-diol esters, o-diphenol esters, 1,8-naphthol esters, cycloalkyl o-diphenol esters, and amide esters. The cocatalyst i is a hydrocarbon-based aluminum compound; The external electron donor is of general formula R. 3 m R 4 n Si(OR 5 ) 4-m-n The organosilicon compound shown has the following formula: R 3 R 4 Each group is independently selected from C1-C12 straight-chain, branched, or cyclic aliphatic groups, or C3-C12 nitrogen-containing straight-chain, branched, or cyclic organic groups; R 5 Selected from C1-C4 straight-chain or branched aliphatic groups; m and n are natural numbers, and their values ​​satisfy 0≤(m+n)≤2.

8. The chlorination treatment method according to claim 7, characterized in that, The co-catalyst i is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, and trihexylaluminum.

9. The chlorination treatment method according to claim 7, characterized in that, The external electron donor is selected from dimethyldimethoxysilane, diphenyldimethoxysilane, methylcyclopentyldimethoxysilane, methylcyclohexyldimethoxysilane, methyl(3,3,3-trifluoropropyl)dimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, di-n-propyldimethoxysilane, di-n-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isopropylisopentyldimethoxysilane, methylcyclopentyldiethoxysilane, methylcyclohexyldiethoxysilane, methyl(3,3,3-trifluoropropyl)diethoxysilane, dicyclopentyldiethoxysilane, dicyclohexyldiethoxysilane, di-n-propyldiethoxysilane, di-n-butyldiethoxysilane, diisopropyldiethoxysilane, di-n-butyldiethoxysilane, di-n- ... One or more of the following: oxysilane, diisobutyldiethoxysilane, isopropylisopentyldiethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isopentyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, allyltrimethoxysilane, vinyltrimethoxysilane, diethylaminotrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isobutyltriethoxysilane, isopentyltriethoxysilane, cyclopentyltriethoxysilane, cyclohexyltriethoxysilane, allyltriethoxysilane, vinyltriethoxysilane, diethylaminotriethoxysilane, tetramethoxysilane, and tetraethoxysilane.

10. The chlorination treatment method according to claim 1, characterized in that, The metallocene catalyst comprises a support, a metallocene coordination compound, and a co-catalyst; wherein: The carrier is selected from particulate silica or layered silicate; The metallocene coordination compound is selected from bridged C2-symmetrical compounds containing a group IV metal and an indenyl group; The cocatalyst ii is selected from methylaluminoxane or modified methylaluminoxane.

11. The chlorination treatment method according to claim 10, characterized in that, The metallocene coordination compound is selected from one or more of rac-dimethylsilyl-bis(2-methyl-4-phenylindenyl)zirconia, rac-dimethylsilyl-bis(2-methyl-4,5-benzylindenyl)zirconia, rac-dimethylsilyl-bis(2-methyl-4-carbazolylindenyl)zirconia and rac-dimethylsilyl-bis[2-methyl-4-(3,5-di-tert-butylphenyl)-7-methoxyindenyl]zirconia.

12. The chlorinated modified catalyst prepared by the chlorination treatment method according to any one of claims 1-11, characterized in that, It is a Ziegler-Natta catalyst containing a polymer nucleating agent after chlorination modification, wherein the polymer nucleating agent is selected from one or more of poly(vinylcyclohexane), poly(vinylcyclopentane), poly(styrene), and poly(allyltrimethylsilane); The catalyst comprises magnesium, titanium, chlorine, and an internal electron donor; The internal electron donor is selected from one or more of the following: benzoic acid esters, phthalic acid esters, 1,3-diethers, succinic acid esters, maleic acid esters, malonic acid esters, 1,3-diol esters, 2,4-diol esters, o-diphenol esters, 1,8-naphthol esters, cycloalkyl o-diphenol esters, and amide esters. The catalyst contains the following components that meet the following requirements: 2≥[Cl] / (4*[Ti]+2*[Mg])≥1.02; Wherein, [Cl] is the total molar amount of Cl in the catalyst slurry, [Ti] is the molar amount of Ti in the catalyst slurry, and [Mg] is the molar amount of Mg in the catalyst slurry.

13. The application of the chlorinated modified catalyst obtained by the chlorination treatment method according to any one of claims 1-8 and 10-11 in propylene polymerization, characterized in that, Includes the following steps: In the presence of the chlorinated catalyst, co-catalyst, and optional external electron donor, propylene monomer or propylene is polymerized with one or more other olefins to produce polypropylene; the polymerization temperature is 50 to 120°C, and the polymerization pressure is 0.1 to 5 MPa. The cocatalyst is a hydrocarbon-based aluminum compound, and the external electron donor is of general formula R. 3 m R 4 n Si(OR 5 ) 4-m-n The organosilicon compound shown; wherein, R 3 R 4 Each group is independently selected from C1-C12 straight-chain, branched, or cyclic aliphatic groups, or C3-C12 nitrogen-containing straight-chain, branched, or cyclic organic groups; R 5 Selected from C1-C4 straight-chain or branched aliphatic groups; m and n are natural numbers, and their values ​​satisfy 0≤(m+n)≤2; The other olefins are ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, or 1-octene.

14. The application according to claim 13, characterized in that, The amount of the chlorinated modified catalyst added in the resulting polypropylene ranges from 1 to 500 ppm by mass.

15. The application according to claim 13, characterized in that, The chlorinated catalyst is pre-contacted with a co-catalyst and an optional external electron donor before being added to the polymerization system, with a pre-contact time of 1-60 min; then the material containing the chlorinated catalyst, co-catalyst, and optional external electron donor obtained after pre-contact is added to the polymerization system; or The chlorinated catalyst is not pre-contacted with the co-catalyst and optional external electron donor before being added to the polymerization system. The chlorinated catalyst, co-catalyst and optional external electron donor are added to the polymerization system separately.

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