An external electron donor composition and use thereof

Abstract

This invention relates to an external electron donor composition and its application. The composition is prepared by mixing the components of raw materials; wherein the raw materials include an alkylaluminum compound and two or more external electron donors, and the molar ratio of the two or more external electron donors to the alkylaluminum compound is 1:(0.01–0.1). One embodiment of the external electron donor composition of this invention can be used to prepare a catalytic system for propylene polymers, achieving a comprehensive optimization of high reactivity and high polymer performance.

Description

Technical Field

[0001] This invention relates to external electron donor compositions, and more particularly to an external electron donor composition for use in catalytic systems for the preparation of propylene polymers. Background Technology

[0002] Currently, over 90% of polypropylene production worldwide utilizes the traditional Ziegler-Natta (ZN) catalyst system. This system consists of a main catalyst (containing an internal electron donor), a co-catalyst, and a suitable external electron donor. Typically, the main catalyst is a magnesium-supported Ti metal multi-active-center composition. The internal electron donor is usually a compound such as benzoate, phthalate, diether, glycol ester, or succinate. The co-catalyst is primarily alkylaluminum, and the external electron donor is mainly aromatic carboxylic acid esters and alkoxysilane compounds.

[0003] The catalyst system determines the polymerization reaction's activity, stereoregularity, and hydrogen sensitivity. Using a single type of external electron donor has significant limitations in controlling these three characteristics. Typically, external electron donors with good hydrogen sensitivity exhibit low polymerization activity and stereoregularity, while external electron donor systems with high polymerization activity and stereoregularity often have poor hydrogen sensitivity. Therefore, it is difficult to simultaneously meet the requirements of high polymerization activity and the polymer's high flowability, high rigidity, and high impact resistance by using only a single type of high-hydrogen-sensitivity external electron donor catalyst formulation. Summary of the Invention

[0004] To overcome at least one of the defects of the prior art, in a first aspect, one embodiment of the present invention provides an external electron donor composition, which is prepared by mixing the components of raw materials; wherein the raw materials include an alkyl aluminum compound and two or more external electron donors, and the molar ratio of the two or more external electron donors to the alkyl aluminum compound is 1:(0.01 to 0.1).

[0005] In a second aspect, one embodiment of the present invention provides a catalyst composition comprising a Ziegler-Natta catalyst and the aforementioned external electron donor composition.

[0006] Thirdly, one embodiment of the present invention provides a method for preparing a propylene polymer, comprising polymerizing a monomer under the action of the above-described catalyst composition to obtain the propylene polymer; wherein the monomer comprises propylene.

[0007] An external electron donor composition according to one embodiment of the present invention can be used to prepare a catalytic system for propylene polymers, and can achieve a comprehensive optimization of high reactivity and high polymer performance (e.g., a high polymer melt index). Detailed Implementation

[0008] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the description herein is for illustrative purposes only and not intended to limit the present invention.

[0009] One embodiment of the present invention provides an external electron donor composition, which is prepared by mixing the components of raw materials; wherein the raw materials include alkyl aluminum compounds and two or more external electron donors, and the molar ratio of the two or more external electron donors to the alkyl aluminum compounds is 1:(0.01 to 0.1).

[0010] In one embodiment, the raw materials include alkyl aluminum compounds, anti-caking agents, and two or more external electron donors; the anti-caking agents include one or more of carboxylic acid ester compounds and antistatic agents.

[0011] In one embodiment, two or more external electron donors, alkyl aluminum compounds, and optional anti-caking agents can be mixed at room temperature in a specific ratio and stirred evenly to obtain an external electron donor composition.

[0012] In one embodiment, the molar ratio of two or more external electron donors to the alkylaluminum compound in the external electron donor composition is 1:0.01 to 1:0.1, or the ratio of the sum of the molar numbers of the two or more external electron donors to the molar number of the alkylaluminum compound in the external electron donor composition is 1:0.01 to 1:0.1. Further, the above molar ratio can be 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, or 1:0.09.

[0013] In one embodiment, the molar ratio of two or more external electron donors to the anti-caking agent in the external electron donor composition is 1:99 to 99:1, for example, 1:99, 1:80, 1:50, 1:20, 1:10, 1:1, 10:1, 50:1, 90:1, or 99:1. Wherein, in the above molar ratios, the molar number of external electron donors is the sum of the molar numbers of two or more external electron donors.

[0014] In one embodiment, the alkylaluminum compound in the external electron donor composition includes compounds of the general formula R. 1 m AlCl 3-m The compounds and one or more of methylaluminoxanes, wherein, in R 1 m AlCl 3-m In the diagram, m is 1, 2, or 3, and R... 1It is a straight-chain or branched alkyl group containing 1 to 10 carbon atoms.

[0015] In one implementation, R 1 The number of carbon atoms in a group can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0016] In one implementation, R 1 The group can be an alkyl group containing 1 to 5 carbon atoms.

[0017] In one embodiment, the alkylaluminum compound in the external electron donor composition may be a trialkylaluminum, such as one or more of triethylaluminum (AlEt3), triisobutylaluminum, and tri-n-butylaluminum.

[0018] In one embodiment, the anti-caking agent can be a compound with high-temperature self-extinguishing function (such as a carboxylic acid ester compound) or an antistatic agent with antistatic function.

[0019] In one embodiment, the antistatic agent includes polyamine compounds, stearates or distearates, glyceryl monostearate, dodecylbenzenesulfonic acid, C14-C18 alkyl salicylate compounds, and Atmer. TM 163. Statsafe antistatic agent TM 3000, Statsafe antistatic agent TM One or more of 6000. Further, the polyamine compound may include dimethylamine-epoxychloropropane-ethylenediamine copolymer; the stearate or distearate may include one or more of aluminum stearate, sodium stearate, and calcium stearate.

[0020] In one embodiment, the carboxylic acid ester compound used as an anti-caking agent includes one or more of ethyl acetate, methyl trimethylacetate, amyl valerate, isopropyl tetradecanoate, isopropyl stearate, n-butyl sebacate, mono- or diacetates of polyalkylene glycol, mono- or dimyristate of polyalkylene glycol, mono- or dilaurate of polyalkylene glycol, mono- or dioleate of polyalkylene glycol, glyceryl triacetate, and mixed glyceryl esters of linoleic acid, oleic acid, palmitic acid, and stearic acid.

[0021] In one embodiment, the raw material external electron donor in the external electron donor composition includes two, three, or more of alkoxy-substituted silane compounds and ether compounds.

[0022] In one embodiment, the external electron donor in the external electron donor composition includes two, three, or more alkoxy-substituted silane compounds.

[0023] In one embodiment, the ether compound may include one, two or more of diethyl ether, tetrahydrofuran, diisopentyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, 3-bis(methoxymethyl)-2,5-dimethylhexane, 4,4-bis(methoxymethyl)-2,6-dimethylheptane and 9,9-bis(methoxymethyl)fluorene.

[0024] In one embodiment, the alkoxy-substituted silane compound has the general formula SiR. n (OR') 4-n , 0≤n≤3, R and R' are each independently selected from alkyl, substituted alkyl (e.g. haloalkyl), cycloalkyl (e.g. cyclopentyl), heterocyclic group, aryl (e.g. phenyl), alkenyl, halogen atom, hydrogen atom.

[0025] In one implementation, SiR n (OR') 4-n n can be 0, 1, 2 or 3.

[0026] In one embodiment, the heteroatom in the heterocyclic group can be one or more of group IVA, VA, VIA, and VIIA atoms, such as a nitrogen atom. Further, the heterocyclic group can be a substituted or unsubstituted pyrrole group, a fully hydrogenated isoquinoline group, or a piperidine group.

[0027] In one embodiment, the halogen atom includes one or more of fluorine, chlorine, bromine, and iodine atoms.

[0028] In one embodiment, the number of carbon atoms contained in the R or R' group can be 0 to 20, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0029] In one embodiment, the substituted alkyl group can be a haloalkyl group, wherein the halogen atom can be one or more of fluorine, chlorine, bromine, and iodine atoms.

[0030] In one embodiment, when n is 2 or 3, the alkoxy-substituted silane compound contains two or three R groups. The two or three R groups can be the same group, for example, both of the two or three R groups are methyl; or they can be different groups, for example, one R group is methyl and the other R group is isopropyl.

[0031] In one embodiment, the R group is selected from alkyl groups containing 1 to 20 carbon atoms, alkenyl groups containing 2 to 20 carbon atoms, cycloalkyl groups containing 3 to 20 carbon atoms, heterocyclic groups containing 2 to 20 carbon atoms, aryl groups containing 6 to 20 carbon atoms, haloalkyl groups containing 1 to 20 carbon atoms, halogen atoms, and hydrogen atoms; wherein, the heteroatom in the heterocyclic group is selected from one or more of group IVA, VA, VIA, and VIIA atoms (e.g., nitrogen atoms). Further, the R group can be methyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, cyclopentyl, cyclohexyl, pyrrolyl, perhydroisoquinolinyl, piperidinyl, vinyl, or 1,1,1-trifluoro-2-propyl.

[0032] In one embodiment, the R group is selected from alkyl groups containing 1 to 6 carbon atoms, alkenyl groups containing 2 to 4 carbon atoms, cycloalkyl groups containing 4 to 7 carbon atoms, heterocyclic groups containing 4 to 10 carbon atoms, aryl groups containing 6 to 8 carbon atoms, or haloalkyl groups containing 1 to 5 carbon atoms.

[0033] In one embodiment, the R group is selected from alkyl groups containing 1 to 6 carbon atoms or cycloalkyl groups containing 4 to 6 carbon atoms.

[0034] In one embodiment, when n is 0, 1, or 2, the alkoxy-substituted silane compound contains two, three, or four R' groups. The two, three, or four R' groups can be the same group, for example, all of them are ethyl (tetraethoxysilane); or they can be different groups, for example, one R' group is methyl and the other R' group is ethyl.

[0035] In one embodiment, the R' group is selected from alkyl groups containing 1 to 20 carbon atoms, cycloalkyl groups containing 3 to 20 carbon atoms, aryl groups containing 6 to 20 carbon atoms, and haloalkyl groups containing 1 to 20 carbon atoms. Further, the R' group can be methyl, ethyl, or phenyl.

[0036] In one embodiment, the R' group is selected from alkyl groups containing 1 to 3 carbon atoms or aryl groups containing 6 to 8 carbon atoms.

[0037] In one embodiment, the alkoxy-substituted silane compounds include tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyl tert-butyldimethoxysilane, methyl isopropyldimethoxysilane, vinyltrimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, and diisobutyldimethoxysilane. One, two, or more of the following: silane, di-tert-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane, cyclohexylpyrrolidinyldimethoxysilane, dipyrrolidinyldimethoxysilane, bis(perhydroisoquinoline)dimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane.

[0038] In one embodiment, the two or more external electron donors include two, three or more of diisobutyldimethoxysilane, tetraethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, methylcyclohexyldimethoxysilane, n-propyltrimethoxysilane, and n-propyltriethoxysilane.

[0039] In one embodiment, the raw materials for the external electron donor include two or more external electron donors, and the molar content of each external electron donor is more than 1% (or at least 1%), based on the sum of the molar numbers of the two or more external electron donors.

[0040] In one embodiment, the external electron donor includes two types of external electron donors: a first external electron donor and a second external electron donor. Based on the sum of the molar numbers of the two external electron donors, the molar content of the first external electron donor can be 1–99%, for example, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 98%. The molar content of the second external electron donor can also be 1–99%, for example, 1%, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 98%.

[0041] In one embodiment, the raw material for the external electron donor includes three external electron donors: a first external electron donor, a second external electron donor, and a third external electron donor. Based on the sum of the molar numbers of the three external electron donors, the molar content of the first external electron donor can be 1-98%, for example, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 97%. The molar content of the second external electron donor can be 1-98%, for example... For example, 1%, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%; the molar content of the third external electron donor can be 1% to 98%, for example, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%.

[0042] One embodiment of the present invention provides a catalyst composition comprising a Ziegler-Natta catalyst and the above-described external electron donor composition.

[0043] In one embodiment, the Ziegler-Natta catalyst includes a main catalyst and a co-catalyst, wherein the main catalyst contains titanium and the co-catalyst comprises an organoaluminum compound. Further, the Ziegler-Natta catalyst may also include an external electron donor, the type of which may be selected from the types of external electron donors contained in the aforementioned external electron donor composition.

[0044] In one embodiment, the main catalyst of the Ziegler-Natta catalyst can be a fourth-generation catalyst using phthalate internal electron donors, which is commonly used in industrial production plants.

[0045] In one embodiment, the co-catalyst for the Ziegler-Natta catalyst may be an alkylaluminum, which may be selected from the alkylaluminum compounds in the aforementioned external electron donor composition, such as one, two or three of triethylaluminum (AlEt3), triisobutylaluminum, tri-n-butylaluminum and methylaluminoxane.

[0046] In one embodiment, the molar ratio (Ti / Al) of titanium in the main catalyst to aluminum in the co-catalyst of the Ziegler-Natta catalyst can be 1:5 to 1:100, for example 1:20, 1:25, 1:30, 1:40, 1:60, 1:70, 1:80, or 1:90.

[0047] In one embodiment, the molar ratio of the active component Ti in the Ziegler-Natta catalyst to the Si element in the external electron donor composition can be Ti / Si = 0.01 to 10, for example 0.025, 0.05, 0.07, 0.1, 0.2, 0.5, 1, 2.

[0048] One embodiment of the present invention provides a method for preparing a propylene polymer, comprising polymerizing a monomer using the above-mentioned catalyst composition as a catalytic system to obtain a propylene polymer; wherein the monomer includes propylene.

[0049] In one embodiment, the propylene polymer can be a homopolymer of propylene (i.e., polypropylene) or a copolymer of propylene (e.g., a random copolymer). Accordingly, in the preparation of the propylene polymer, the monomers polymerized can be propylene alone or may include other olefins.

[0050] In one embodiment, the monomer includes propylene and one or more other olefins; further, the other olefins include ethylene and other α-olefins, including 1-butene and 1-hexene.

[0051] In one embodiment, the monomer includes propylene, and one or more of ethylene, 1-butene, and 1-hexene.

[0052] In one embodiment, the resulting propylene polymer is a propylene-ethylene random copolymer, and correspondingly, the monomers in the polymerization reaction include propylene and ethylene.

[0053] In one embodiment, the raw materials used for the reaction in the preparation of propylene polymers include monomers and hydrogen.

[0054] In one embodiment, in the preparation of propylene polymers, the polymerization temperature can be 40–100°C, preferably 50–70°C; the polymerization pressure can be 0.5–5 MPa, preferably 2.0–2.3 MPa.

[0055] In one embodiment, in the preparation of propylene polymers, the polymerization reaction of the monomers is carried out in a polymerization reactor. A Ziegler-Natta catalyst and an external electron donor composition can be added into the polymerization reactor for phase contact to catalyze the polymerization of the monomers. After flash evaporation, separation, deactivation and other treatments, the propylene polymers are obtained.

[0056] In one embodiment, the apparatus for preparing propylene polymers may include one or more polymerization reactors and optionally a prepolymerization reactor. Further, the one or more (e.g., two) polymerization reactors may be olefin polymerization reactors such as gas-phase fluidized bed reactors, vertical stirred tanks with mechanical agitation, or horizontal stirred tanks. The prepolymerization reactor may be a stirred tank, a loop reactor, or a gas-phase fluidized bed.

[0057] An embodiment of the present invention provides an external electron donor composition or a catalyst system comprising the composition, which can be used for the gas-phase homopolymerization or copolymerization of propylene. This enables the reaction system to exhibit high polymerization activity, thereby obtaining more product per unit time, improving production efficiency, and reducing production costs. Simultaneously, it also allows the resulting polymer to possess properties such as high melt flow rate.

[0058] An external electron donor composition or a catalyst system containing the composition according to one embodiment of the present invention can be used in the preparation of propylene polymers, which can significantly reduce reactor agglomeration during polymerization, thereby ensuring stable operation of the equipment.

[0059] One embodiment of the present invention provides an external electron donor composition that, when combined with a Ziegler-Natta catalyst, can, to a certain extent, not only compensate for and overcome the limitations of a single external electron donor catalyst system, enabling the catalyst system to simultaneously possess high stereoregulation capability and good hydrogen regulation performance, but also endow the catalyst system with superior functionality such as maintaining high polymerization activity and preventing agglomeration. This results in a significant improvement in the overall performance of propylene polymer products, a substantial increase in the stability of equipment operation, and improved production efficiency.

[0060] One embodiment of the present invention discloses a catalyst system comprising an external electron donor composition. Through the synergistic effect between the components, a polypropylene catalyst exhibiting high activity, high hydrogen regulation, and high stereoregulation can be formed. Furthermore, this catalyst system prevents resin material from agglomerating within the reactor, making it particularly suitable for propylene gas-phase polymerization or copolymerization processes. This catalyst system can be used to prepare polypropylene products possessing high melt flow rate (MFR), high modulus, and high impact resistance.

[0061] One embodiment of the present invention discloses a method for preparing propylene polymers, which employs an external electron donor composition in the catalytic system. This method can produce high-performance propylene polymers, while also increasing the activity of the polymerization reaction, preventing agglomeration during the reaction process, and ensuring stable operation of the reaction apparatus. Specifically, it can improve the melt flow rate and rigidity-toughness balance of the propylene polymers, and extend the time interval for the sieve to remove agglomerated material by 2 to 12 times.

[0062] The preparation of a propylene polymer according to one embodiment of the present invention will be further described below with reference to examples. At least some of the raw materials and testing methods involved in each example and comparative example are as follows.

[0063] raw material 1. Preparation of external electron donor composition At room temperature and in a nitrogen atmosphere, a variety of external electron donor compounds are mixed in proportion, and then an alkyl aluminum compound and an optional anti-caking agent are added and mixed, and stirred evenly; wherein the specific types and amounts of each component are described in the examples, comparative examples and Table 1.

[0064] 2. The active component of the Ziegler-Natta (ZN) catalyst used is mineral oil as a diluent, and its solid content is 30.0 wt%; of which, the mass content of titanium is 2.70 wt%, the mass content of magnesium is 17.15 wt%, and the mass content of internal electron donor (di-n-butyl phthalate) is 11.33 wt%.

[0065] Test methods 1. Polymerization activity The polymerization activity is calculated based on the ratio of the unit's operating load to the catalyst feed rate.

[0066] 2. Melt Flow Rate (MFR) (or Melt Index) The melt flow rate of propylene polymers was measured according to ASTM D1238 under conditions of 230°C and a 2.16 kg weight load.

[0067] 3. Flexural modulus The flexural modulus of propylene polymers was measured according to GB / T 9341-2008.

[0068] 4. Impact strength The impact strength of propylene polymers was measured according to GB / T 1843-2008.

[0069] All embodiments and comparative examples used the INNOVENE gas-phase polypropylene apparatus, which is a horizontal gas-phase reactor. The material flow pattern inside the reactor is close to plug flow. The entire reactor can be approximated as a series of stirred tanks. There is a temperature gradient in the polymerization temperature from one end to the other. The polymerization temperature range is controlled from one end to the other at 65-70°C, divided into 6 zones with temperatures of 65°C, 66°C, 67°C, 68°C, 69°C, and 70°C, respectively.

[0070] Example 1 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 4.50 kg / h, the AlEt3 feed rate was 5.41 kg / h, the external electron donor composition feed rate was 2.47 kg / h, the propylene feed rate was 32.00 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.05 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit's production load was 43.20 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0071] The raw materials of the external electron donor composition include a first external electron donor, diisobutyldimethoxysilane (B), a second external electron donor, tetraethoxysilane (T), and triethylaluminum (Al), wherein the molar ratio of B / T in the external electron donor composition is 5:95; the molar ratio of the sum of the molar numbers of the two external electron donors to triethylaluminum is (B+T):Al = 1:0.1.

[0072] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0073] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0074] Example 2 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 4.55 kg / h, the AlEt3 feed rate was 5.49 kg / h, the external electron donor composition feed rate was 2.50 kg / h, the propylene feed rate was 32.00 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.05 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit operating load was 43.40 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0075] The raw materials of the external electron donor composition include a first external electron donor, diisobutyldimethoxysilane (B), a second external electron donor, tetraethoxysilane (T), triethylaluminum (Al), and an anti-caking agent, isopropyl tetradecanoate (IPM). The molar ratio of B / T in the external electron donor composition is 5:95. The molar ratio of the sum of the two external electron donors to triethylaluminum and IPM is (B+T):Al:IPM = 1:0.1:1.

[0076] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0077] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0078] Example 3 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 4.40 kg / h, the AlEt3 feed rate was 5.42 kg / h, the external electron donor composition feed rate was 2.47 kg / h, the propylene feed rate was 33.55 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.05 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit operating load was 45.00 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0079] The raw materials of the external electron donor composition include a first external electron donor, diisobutyldimethoxysilane (B), a second external electron donor, dicyclopentyldimethoxysilane (D), a third external electron donor, tetraethoxysilane (T), triethylaluminum (Al), and an anti-caking agent, isopropyl tetradecanoate (IPM). The molar ratio of B / D / T in the external electron donor composition is 4:1:95. The molar ratio of the sum of the three external electron donors to triethylaluminum and IPM is (B+D+T):Al:IPM = 1:0.1:1.

[0080] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0081] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0082] Example 4 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 4.28 kg / h, the AlEt3 feed rate was 5.42 kg / h, the external electron donor composition feed rate was 2.47 kg / h, the propylene feed rate was 33.50 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.05 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit operating load was 45.00 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0083] The raw materials of the external electron donor composition include a first external electron donor, diisopropyl dimethoxysilane (P), a second external electron donor, dicyclopentyl dimethoxysilane (D), a third external electron donor, tetraethoxysilane (T), triethylaluminum (Al), and an anti-caking agent, isopropyl tetradecanoate (IPM). The molar ratio of P / D / T in the external electron donor composition is 3:2:95. The molar ratio of the sum of the three external electron donors to triethylaluminum and IPM is (P+D+T):Al:IPM = 1:0.1:1.

[0084] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0085] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0086] Example 5 This embodiment uses essentially the same raw materials and process conditions as Example 2 to prepare propylene polymers, the only difference being the molar ratio of the first electron donor, diisobutyldimethoxysilane (B), to the second electron donor, tetraethoxysilane (T), in the raw materials of the external electron donor composition. The molar ratio of the first electron donor, diisobutyldimethoxysilane (B), to the second electron donor, tetraethoxysilane (T), is B:T = 10:90; the molar ratio of the sum of the molar numbers of the two electron donors to triethylaluminum (Al) and the anti-caking agent isopropyl tetradecanoate (IPM) is (B+T):Al:IPM = 1:0.1:1.

[0087] Example 6 This embodiment uses essentially the same raw materials and processes as Example 2 to prepare propylene polymers, the only difference being that the two types of external electron donors in the external electron donor composition are different, namely n-propyltrimethoxysilane (PTMS) and tetraethoxysilane (T), and the molar ratio of the two external electron donors is PTMS:T = 10:90; the molar ratio of the sum of the two external electron donors to triethylaluminum (Al) and the anti-caking agent isopropyl tetradecanoate (IPM) is (PTMS+T):Al:IPM = 1:0.1:1.

[0088] Example 7 This embodiment uses essentially the same raw materials and processes as Example 2 to prepare propylene polymers, the only difference being that the type of antistatic agent in the external electron donor composition is different; it is dodecylbenzenesulfonic acid (DBSA). The molar ratio of the sum of the two external electron donors to triethylaluminum (Al) and the antistatic agent dodecylbenzenesulfonic acid is: (B+T):Al:DBSA = 1:0.1:1.

[0089] Example 8 This embodiment uses the same raw materials and processes as Example 2 to prepare propylene polymers. The only difference is that in the raw materials of the external electron donor composition, the molar ratio of the sum of the two external electron donors to triethylaluminum (Al) and the anti-caking agent isopropyl tetradecanoate (IPM) is: (B+T):Al:IPM = 1:0.01:1.

[0090] Comparative Example 1 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 4.50 kg / h, the AlEt3 feed rate was 5.42 kg / h, the external electron donor diisobutyldimethoxysilane (B) feed rate was 2.47 kg / h, the propylene feed rate was 33.50 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.25 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit's production load was 45.10 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0091] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0092] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0093] Comparative Example 2 Propylene-ethylene random copolymers were produced using a Zn catalyst in the INNOVENE gas-phase polypropylene unit. A two-reactor series production process was employed. In the first reactor, the Zn catalyst feed rate was 5.20 kg / h, the AlEt3 feed rate was 5.41 kg / h, the external electron donor composition feed rate was 2.47 kg / h, the propylene feed rate was 30.90 t / h, the ethylene feed rate was 1.36 t / h, and the hydrogen feed rate was 1.10 kg / h. In the second reactor, the propylene feed rate was 10.00 t / h, the ethylene feed rate was 0.45 t / h, and the hydrogen feed rate was 2.30 kg / h. The unit's production load was 42.12 t / h, the polymerization temperature was 65–70 °C, and the polymerization pressure was 2.0–2.3 MPa.

[0094] The external electron donor composition includes a first external electron donor, diisobutyldimethoxysilane (B), and a second external electron donor, tetraethoxysilane (T), with a molar ratio of B:T = 5:95.

[0095] The overall Al / Si ratio in the catalyst system was controlled to be 4, and the Ti / Si ratio to be 0.06. These ratios are molar ratios.

[0096] The obtained propylene polymers were subjected to performance tests according to the aforementioned method. At the same time, the time interval for the sieve on the device to clean up the lumps was recorded, and the weight of the lumps cleaned up each time was weighed and recorded. The results are shown in Table 1.

[0097] Tables 1 and 2 list the addition of some raw materials, polymerization activity, weight of the cleaned-up lumps, and performance parameters of the resulting propylene polymers in each embodiment and comparative example.

[0098] Table 1

[0099] Table 2

[0100] Referring to Example 1 and Comparative Example 2, the main difference lies in the fact that the external electron donor composition in Example 1 also includes triethylaluminum. According to the data in Table 1, the polymerization activity of Example 1 is 32000 g polymer / g catalyst / h, while that of Comparative Example 2 is 27000 g polymer / g catalyst / h. This shows that the polymerization activity of Example 1 is significantly higher than that of Comparative Example 2. Furthermore, although the catalytic system of Comparative Example 2 also includes triethylaluminum, it is added separately. The above results indicate that separately added triethylaluminum cannot perform the function of triethylaluminum in the external electron donor composition.

[0101] Furthermore, by converting the polymerization activities of Example 1 and Comparative Example 2 (using catalyst feed rate × polymerization activity), the operating load or output of the unit can be obtained. Specifically, the output of Example 1 is: 4.50 kg / h × 1000 × 30% (mass percentage concentration of solid content in the catalyst) × 320000 g polymer / g catalyst / h = 43.2 × 10⁻⁶ 6 The yield of Comparative Example 2 is: 5.20 kg / h × 1000 × 30% (mass percentage concentration of solid content in the catalyst) × 270000 g polymer / g catalyst / h = 42.12 × 10 6 g / h = 42.12 t / h. In comparison, the yield of Example 1 is approximately 1 t / h higher than that of Comparative Example 2. Therefore, the method for preparing propylene polymers according to this invention, by using an external electron donor composition obtained by mixing two or more external electron donors and alkylaluminum compounds in the catalytic system, can significantly improve polymerization activity, thereby increasing yield and improving production efficiency.

[0102] Referring to Comparative Examples 1 and 2 and Example 1, the main difference between the three lies in the catalytic system: Comparative Example 1 used one external electron donor, Comparative Example 2 used two external electron donors, and Example 1 used an external electron donor composition containing triethylaluminum and two external electron donors. According to the data in Table 1, the polymer melt index and impact strength of Comparative Example 2 were significantly higher than those of Comparative Example 1, but its polymerization activity was significantly lower. That is, while increasing the types of external electron donors helps improve the polymer melt index, it affects the polymerization activity of the system. The polymerization activity of Example 1 was similar to that of Comparative Example 1, and the polymer melt index and impact strength were similar to those of Comparative Example 2. Therefore, in the catalytic system, the external electron donor composition obtained by using two or more external electron donors and a mixture of alkylaluminum compounds can overcome the defects of using only one or two external electron donors, achieving comprehensive optimization of polymer melt index and other properties, as well as polymerization activity.

[0103] Referring to Examples 1 and 2, the main difference lies in the fact that the raw materials of the external electron donor composition in Example 2 also include the anti-caking agent isopropyl myristate (IPM). According to the data in Table 1, the sieve cleaning interval of 120 hours in Example 2 is significantly longer than the cleaning interval of 24 hours in Example 1, and the amount of lumps in Example 2 (2.0 kg / batch) is significantly less than the amount of lumps in Example 1 (5.3 kg / batch). Therefore, by adding an anti-caking agent to the raw materials of the external electron donor composition, this invention can significantly reduce the amount of lumps generated during the reaction, thus ensuring stable operation of the reaction apparatus.

[0104] Unless otherwise specified, the terms used in this invention have the meanings commonly understood by those skilled in the art.

[0105] The embodiments described in this invention are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. An external electron donor composition, prepared by mixing the components of raw materials; wherein, The raw materials include alkylaluminum compounds and two or more external electron donors, wherein the molar ratio of the two or more external electron donors to the alkylaluminum compounds is 1:(0.01 to 0.1).

2. The composition according to claim 1, wherein, The raw materials also include an anti-caking agent, which includes one or more of carboxylic acid ester compounds and antistatic agents; and / or, The alkylaluminum compounds include those with the general formula R. 1 m AlCl 3-m One or more of the compounds and methylaluminoxanes, wherein m is 1, 2 or 3, R 1 It is a straight-chain or branched alkyl group containing 1 to 10 carbon atoms; and / or, The two or more external electron donors include two, three or more of alkoxy-substituted silane compounds and ether compounds.

3. The composition according to claim 2, wherein, The molar ratio of the anti-caking agent to the two or more external electron donors is 1:99 to 99:1; and / or, R 1 The group is selected from straight-chain or branched alkyl groups containing 1 to 5 carbon atoms; and / or, The general formula of the alkoxy-substituted silane compounds is SiR. n (OR') 4-n , 0≤n≤3, R and R' are each independently selected from alkyl, substituted alkyl, cycloalkyl, heterocyclic groups, aryl, alkenyl, halogen atoms, hydrogen atoms; and / or, The antistatic agent includes polyamine compounds, stearates or distearates, glyceryl monostearate, dodecylbenzenesulfonic acid, C14-C18 alkyl salicylate compounds, and Atmer. TM 163. Statsafe TM 3000, Statsafe TM One or more of 6000; and / or, The carboxylic acid ester compounds include one or more of the following: ethyl acetate, methyl trimethylacetate, pentyl valerate, isopropyl tetradecanoate, isopropyl stearate, n-butyl sebacate, mono- or diacetates of polyalkylene glycol, mono- or dimyristate of polyalkylene glycol, mono- or dilaurate of polyalkylene glycol, mono- or dioleate of polyalkylene glycol, glyceryl triacetate, and mixed glyceryl esters of linoleic acid, oleic acid, palmitic acid, and stearic acid.

4. The composition according to claim 3, wherein, R is selected from alkyl groups containing 1 to 20 carbon atoms, alkenyl groups containing 2 to 20 carbon atoms, cycloalkyl groups containing 3 to 20 carbon atoms, heterocyclic groups containing 2 to 20 carbon atoms, aryl groups containing 6 to 20 carbon atoms, haloalkyl groups containing 1 to 20 carbon atoms, halogen atoms, and hydrogen atoms, wherein the heteroatom in the heterocyclic group is selected from one or more of group IVA, VA, VIA, and VIIA atoms; R' is selected from alkyl groups containing 1 to 20 carbon atoms, cycloalkyl groups containing 3 to 20 carbon atoms, aryl groups containing 6 to 20 carbon atoms, and haloalkyl groups containing 1 to 20 carbon atoms; and / or, The polyamine compound includes a dimethylamine-epoxychloropropane-ethylenediamine copolymer; the stearate or distearate includes one or more of aluminum stearate, sodium stearate, and calcium stearate; and / or The alkylaluminum compounds include one or more of triethylaluminum, triisobutylaluminum, and tri-n-butylaluminum.

5. The composition according to claim 2, wherein, The alkoxy-substituted silane compounds include tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyl tert-butyldimethoxysilane, methyl isopropyldimethoxysilane, vinyltrimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, and di-... One, two, or more of the following: tert-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane, cyclohexylpyrrolidinyldimethoxysilane, dipyrrolidinyldimethoxysilane, bis(perhydroisoquinoline)dimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane; and / or, The ether compounds include one, two or more of the following: diethyl ether, tetrahydrofuran, diisopentyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, 3-bis(methoxymethyl)-2,5-dimethylhexane, 4,4-bis(methoxymethyl)-2,6-dimethylheptane, and 9,9-bis(methoxymethyl)fluorene.

6. The composition according to claim 1, wherein, The molar content of each of the two or more external electron donors is at least 1%.

7. A catalyst composition comprising a Ziegler-Natta catalyst and an external electron donor composition according to any one of claims 1 to 6.

8. The composition according to claim 7, wherein, The Ziegler-Natta catalyst comprises a main catalyst and a co-catalyst, wherein the main catalyst contains titanium and the co-catalyst comprises an organoaluminum compound.

9. A method for preparing a propylene polymer, comprising polymerizing a monomer under the action of the catalyst composition according to claim 7 or 8 to obtain the propylene polymer; wherein, The monomer includes propylene.

10. The preparation method according to claim 9, wherein, The monomer includes propylene, and one or more of optional other olefins; the other olefins include ethylene and other α-olefins, the other α-olefins including 1-butene and 1-hexene.

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