Compound external electron donor for preparing polypropylene, preparation method of compound external electron donor and polypropylene material

Abstract

The invention belongs to the technical field of modified catalysts, and relates to a compound external electron donor for preparing polypropylene, a preparation method of the compound external electron donor and a polypropylene material. The invention discloses a silane coupling agent modification-based compound external electron donor for preparing polypropylene. The compound external electron donor is prepared by carrying out compound modification on a polypropylene catalyst and a specific silane coupling agent in a white oil and / or vaseline medium, the compound external electron donor is applied to a polymerization reaction of a polypropylene material and shows excellent catalytic performance, and the obtained polypropylene material has higher melt flow rate, good rigidity and excellent impact resistance and can better meet the requirements of high-end plastic products.

Description

Technical Field

[0001] This invention belongs to the field of modified catalyst technology, and relates to a compound external electron donor for preparing polypropylene, its preparation method, and polypropylene materials. Background Technology

[0002] Against the backdrop of continuous upgrading in industries such as automobiles, high-end sectors are placing more stringent demands on material performance. Traditional polypropylene materials struggle to simultaneously meet the dual requirements of efficient processing and excellent mechanical properties. In contrast, high-performance impact-resistant polypropylene, while maintaining a high melt flow rate, also possesses high modulus and high impact resistance, making it one of the key materials for meeting the requirements of lightweighting and structural safety in automobiles.

[0003] In polypropylene catalytic systems, the choice of external electron donor has a decisive impact on catalyst activity, hydrogen sensitivity, and polymer molecular weight distribution. In existing technologies, introducing specific external electron donors to regulate the stereoregularity and copolymerization properties of polypropylene is a common method to improve the material's rigidity-ductility balance. Current research has used ionic liquids as external electron donors to modify polypropylene catalysts; however, this method still has significant shortcomings in practical applications. First, the compatibility between ionic liquids and polypropylene catalyst systems is poor, leading to unstable modification effects, especially in large-scale industrial production where catalyst activity fluctuates significantly, making it difficult to ensure consistent performance across multiple batches of products. Second, the synthesis cost of ionic liquids is high, and some ionic liquids may retain polar groups during polymerization, affecting the polymer's dielectric properties and thermal stability, limiting their application in high-end automotive injection molded parts and other fields with stringent requirements for material purity and stability.

[0004] Therefore, there is an urgent need to develop a new external electron donor modification technology that has better compatibility with polypropylene catalyst systems, stable modification effects, and controllable costs, in order to simplify the process flow, improve the copolymerization performance and polymerization activity stability of the catalyst, and meet the demand for large-scale production of high-performance polypropylene materials for automotive lightweighting and high-end injection molded products. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a compound external electron donor based on silane coupling agent modification for the preparation of polypropylene. This compound external electron donor is prepared by compounding and modifying a polypropylene catalyst with a specific silane coupling agent in a white oil and / or petrolatum medium. When applied to the polymerization reaction of polypropylene, this compound external electron donor exhibits excellent catalytic performance, and the resulting polypropylene material has a high melt flow rate, good rigidity, and excellent impact resistance, which can better meet the needs of high-end plastic products.

[0006] One objective of this invention is achieved through the following technical solution: A method for preparing a compound external electron donor for polypropylene includes the following steps: mixing polypropylene catalyst, white oil and petrolatum in a mass ratio of (5~50):(25~90):(0~100) to obtain a mixture, then adjusting the temperature of the mixture to 0~25℃, adding a silane coupling agent, and stirring the reaction. The amount of the silane coupling agent added is 0.1~3 wt% of the mass of the mixture; The general structural formula of the silane coupling agent is H2N-R-Si(OC2H5)3 or H2N-R2-NH-R1-Si(OC2H5)3; Wherein, R is selected from C1~C 12 At least one of linear alkylene or phenylene-C6H4-; R1 and R2 are each independently selected from C1 to C2. 12 Straight-chain alkylene groups.

[0007] Preferably, the silane coupling agent includes at least one of the following L1 to L6 silane coupling agents: L1 silane coupling agent: structural formula is H2N-CH2-Si(OC2H5)3; L2 silane coupling agent: structural formula H2N-(CH2) 11 -Si(OC2H5)3; L3 silane coupling agent: structural formula is H2N-(CH2)4-Si(OC2H5)3; L4 silane coupling agent: structural formula is H2N-C6H4-Si(OC2H5)3; L5 silane coupling agent: structural formula is H2N-(CH2)6-NH-CH2-Si(OC2H5)3; L6 silane coupling agent: The structural formula is H2N-(CH2)2-NH-(CH2)3-Si(OC2H5)3.

[0008] Preferably, the polypropylene catalyst is a Ziegler-Natta type catalyst, including a titanium-based solid catalyst supported on magnesium chloride.

[0009] Preferably, the polypropylene catalyst further includes at least one of the following: a Ziegler-Natta catalyst specifically for high hydrogen sensitivity, high isotacticity, or wide molecular weight distribution.

[0010] Preferably, the mixing temperature is 10~30℃ and the time is 1~60min.

[0011] Preferably, the temperature of the stirring reaction is 0~25℃ and the time is 5~600min.

[0012] The second objective of this invention is achieved through the following technical solution: A compound external electron donor for preparing polypropylene is prepared by the method described above.

[0013] Preferably, the composite external electron donor used to prepare polypropylene is a modified polypropylene catalyst system obtained by modifying the polypropylene catalyst with a silane coupling agent.

[0014] The third objective of this invention is achieved through the following technical solution: A polypropylene material, the raw materials of which include the aforementioned compounded external electron donors used to prepare polypropylene.

[0015] Preferably, the raw materials for the polypropylene material also include other external electron donors; The other external electron donors include at least one of diisopropyldimethoxysilane (DIPMS), dicyclopentyldimethoxysilane (DCPMS), diisobutyldimethoxysilane (DIBMS), and cyclohexylmethyldimethoxysilane (CHMMS).

[0016] Further preferably, the mass ratio of the composite external electron donor to the other external electron donors is 1:(30~150).

[0017] Preferably, the polypropylene material includes homopolymer polypropylene and / or impact-resistant polypropylene.

[0018] Further preferably, the homopolymer polypropylene is obtained by homopolymerization of propylene, and its preparation method includes the following steps: In the polymerization test apparatus, the gas is replaced sequentially with nitrogen and propylene; then propylene monomer, co-catalyst, the compounded external electron donor and other external electron donors are added; the temperature is raised to the polymerization temperature to carry out the reaction, and homopolymer polypropylene is obtained.

[0019] More preferably, the mass ratio of the propylene monomer, co-catalyst, compounded external electron donor and other external electron donors is (50000~200000):(10~50):1:(30~150).

[0020] More preferably, the co-catalyst is an alkylaluminum compound; The alkylaluminum compound includes at least one of triethylaluminum, triisobutylaluminum, trimethylaluminum, and trihexylaluminum; The alkylaluminum compound is added in the form of a hydrocarbon solution, wherein the hydrocarbon solvent includes at least one of hexane, heptane, toluene, and xylene.

[0021] More preferably, the impact-resistant polypropylene is obtained by impact copolymerization, and its preparation method includes the following steps: In a dual-reactor tandem polymerization simulator, nitrogen and propylene are used to replace the gas in sequence; propylene monomer, co-catalyst, the compounded external electron donor, and other external electron donors are added to the first reactor; the temperature is raised to the first polymerization temperature to carry out the first polymerization reaction, and an intermediate product is obtained; the intermediate product is pressed into the second reactor, and a mixture of ethylene and propylene monomers is added; under reaction pressure, the temperature is raised to the second polymerization temperature to carry out the second polymerization reaction, and impact-resistant polypropylene is obtained.

[0022] More preferably, the mass ratio of the propylene monomer, co-catalyst, compounded external electron donor and other external electron donors is (50000~200000):(10~50):1:(30~150).

[0023] More preferably, the total mass ratio of the mixed monomers of ethylene and propylene to the mass ratio of the propylene monomers is (0.05~0.5):1.

[0024] More preferably, the co-catalyst is an alkylaluminum compound; The alkylaluminum compound includes at least one of triethylaluminum, triisobutylaluminum, trimethylaluminum, and trihexylaluminum; The alkylaluminum compound is added in the form of a hydrocarbon solution, wherein the hydrocarbon solvent includes at least one of hexane, heptane, toluene, and xylene.

[0025] More preferably, the first polymerization temperature is 60~75℃, the second polymerization temperature is 75~85℃, and the third polymerization temperature is greater than the first polymerization temperature.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. The compound external electron donor of the present invention for preparing polypropylene exhibits excellent hydrogen regulation sensitivity in copolymerization reaction, significantly improves polymerization activity, and can more accurately control polymer molecular weight to meet the production needs of different grades of products.

[0027] 2. The compound external electron donor of the present invention for preparing polypropylene exhibits excellent copolymerization performance in both homopolymerization and impact copolymerization reactions. The resulting polymer has a narrower molecular weight distribution and a more uniform microstructure. The compatibility between the rubber phase and the homopolymer matrix is ​​significantly improved, effectively enhancing the structural uniformity of the polypropylene material.

[0028] 3. Compared with the unmodified polypropylene catalyst system and other existing modified polypropylene catalyst systems, the modified polypropylene catalyst system of this invention can achieve a good balance between material processing fluidity and mechanical properties, and better meet the stringent requirements of high-end plastic products for high-performance polypropylene. Detailed Implementation

[0029] The technical solution of the present invention will be further described and illustrated below through specific embodiments. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the present invention.

[0030] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used in the art, and the methods used in the embodiments are all conventional methods in the art.

[0031] In this article, the raw materials include: L1 silane coupling agent: aminomethyltriethoxysilane, CAS: 18306-83-7, structural formula is H2N-CH2-Si(OC2H5)3; L2 silane coupling agent: 11-aminoundecyltriethoxysilane, CAS: 116821-45-5, structural formula H2N-(CH2). 11 -Si(OC2H5)3; L3 silane coupling agent: 4-aminobutyltriethoxysilane, CAS: 3069-30-5, structural formula is H2N-(CH2)4-Si(OC2H5)3; L4 silane coupling agent: 4-phenylaminotriethoxysilane, CAS: 7003-80-7, structural formula is H2N-C6H4-Si(OC2H5)3, where -C6H4- is a para-substituted benzene ring group; L5 silane coupling agent: N-[(6-aminohexyl)amino]methyltriethoxysilane, CAS: 15129-36-9, structural formula is H2N-(CH2)6-NH-CH2-Si(OC2H5)3; L6 silane coupling agent: N-aminoethyl-3-aminopropyltriethoxysilane, CAS: 5089-72-5, structural formula is H2N-(CH2)2-NH-(CH2)3-Si(OC2H5)3; L7 silane coupling agent: ureapropyltriethoxysilane, CAS: 23779-32-0, structural formula is H2N-CO-NH-(CH2)3-Si(OC2H5)3; Polypropylene catalyst: Ziegler-Nata type catalyst. The examples and comparative examples are for illustrative purposes only. CS-1 was used and purchased from Yingkou Xiangyang Catalyst Co., Ltd. ST70 Special White Oil: Liquid Paraffin, CAS: 80042-47-5, purchased from Beijing Optimization Technology Co., Ltd.; Pharmaceutical grade white petrolatum: high purity petrolatum with a purity of ≥99.0%, CAS: 8009-03-8; purchased from Sinopharm Reagent.

[0032] In this study, after adding the silane coupling agent, the reaction was ensured to be complete by stirring for a period of 5 to 600 minutes, specifically 5 minutes, 10 minutes, 30 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 200 minutes, 300 minutes, 400 minutes, 500 minutes, or 600 minutes.

[0033] In this article, the room temperature for the examples and comparative examples is 20~22°C.

[0034] In this article, polypropylene performance testing, Polymerization activity: The ratio of the mass of the polypropylene product after drying to constant weight to the mass of the added main catalyst (i.e., polypropylene catalyst), divided by the polymerization reaction time (h); where the polymerization reaction time is uniformly 2h (homogeneity) or the total reaction time is 2h (impact copolymerization), so the polymerization activity value is directly expressed as g PP / g cat; Xylene-soluble content: Tested according to GB / T 24282-2021: Weigh 1g of the prepared polypropylene sample, dissolve it completely in xylene at a specific temperature, filter and separate, evaporate the filtrate to dryness and weigh the mass of soluble matter; The formula for calculating the rubber phase content is: Xylene-soluble content (%) = (mass of soluble matter / initial mass of sample) × 100%; Melt flow rate, MFR: Tested according to GB / T 3682.1; Flexural modulus: Tested according to GB / T9341; Izod notch impact: Tested according to GB / T1043.2.

[0035] Example 1

[0036] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 25°C, and L1 silane coupling agent is added at a mass of 3wt% of the mixture. The mixture is stirred for 600 minutes to obtain the compound external electron donor for preparing polypropylene.

[0037] Example 2

[0038] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 5°C, and L5 silane coupling agent is added at a mass of 1wt% of the mixture. The mixture is stirred for 400 minutes to obtain the compound external electron donor for preparing polypropylene.

[0039] Example 3

[0040] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 10℃, and L3 silane coupling agent is added at a mass of 0.1wt% of the mixture. The mixture is stirred for 100 minutes to obtain the compound external electron donor for preparing polypropylene.

[0041] Example 4

[0042] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 25°C, and L1 silane coupling agent is added at a mass of 0.5wt% of the mixture. The mixture is stirred for 600 minutes to obtain the compound external electron donor for preparing polypropylene.

[0043] Example 5

[0044] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 5°C, and L5 silane coupling agent is added at a mass of 2wt% of the mixture. The mixture is stirred for 400 minutes to obtain the compound external electron donor for preparing polypropylene.

[0045] Example 6

[0046] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 15℃, and L3 silane coupling agent is added at a mass of 2.5wt% of the mixture. The mixture is stirred for 100 minutes to obtain the compound external electron donor for preparing polypropylene.

[0047] Example 7

[0048] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 20°C, and L2 silane coupling agent is added at a mass of 2.5wt% of the mixture. The mixture is stirred for 30 minutes to obtain the compound external electron donor for preparing polypropylene.

[0049] Example 8 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 0℃, and L6 silane coupling agent is added at a mass of 0.5wt% of the mixture. The mixture is stirred for 500 minutes to obtain the compound external electron donor for preparing polypropylene.

[0050] Example 9

[0051] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 10℃, and L4 silane coupling agent is added at 2wt% of the mass of the mixture. The mixture is stirred for 300 minutes to obtain the compound external electron donor for preparing polypropylene.

[0052] Example 10

[0053] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 0℃, and L6 silane coupling agent is added at a mass of 1.5wt% of the mixture. The mixture is stirred for 500 minutes to obtain the compound external electron donor for preparing polypropylene.

[0054] Example 11

[0055] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 20°C, and L2 silane coupling agent is added at a mass of 0.1wt% of the mixture. The mixture is stirred for 30 minutes to obtain the compound external electron donor for preparing polypropylene.

[0056] Example 12

[0057] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 15°C, and L4 silane coupling agent is added at a mass of 3wt% of the mixture. The mixture is stirred for 300 minutes to obtain the compound external electron donor for preparing polypropylene.

[0058] Example 13

[0059] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 15℃, and L3 silane coupling agent is added at 2wt% of the mass of the mixture. The mixture is stirred for 100 minutes to obtain the compound external electron donor for preparing polypropylene.

[0060] Example 14

[0061] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 25°C, and L1 silane coupling agent is added at a mass of 0.1wt% of the mixture. The mixture is stirred for 600 minutes to obtain the compound external electron donor for preparing polypropylene.

[0062] Example 15

[0063] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 5°C, and L5 silane coupling agent is added at a mass of 1.5wt% of the mixture. The mixture is stirred for 400 minutes to obtain the compound external electron donor for preparing polypropylene.

[0064] Example 16

[0065] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 15°C, and L3 silane coupling agent is added at a mass of 3wt% of the mixture. The mixture is stirred for 100 minutes to obtain the compound external electron donor for preparing polypropylene.

[0066] Example 17

[0067] The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 0℃, and L1 silane coupling agent is added at a mass of 1wt% of the mixture. The mixture is stirred for 600 minutes to obtain the compound external electron donor for preparing polypropylene.

[0068] Example 18 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 20°C, and L5 silane coupling agent is added at a mass of 2.5wt% of the mixture. The mixture is stirred for 400 minutes to obtain the compound external electron donor for preparing polypropylene.

[0069] Example 19 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 10℃, and L4 silane coupling agent is added at a mass of 1.5wt% of the mixture. The mixture is stirred for 300 minutes to obtain the compound external electron donor for preparing polypropylene.

[0070] Example 20 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 20°C, and L2 silane coupling agent is added at a mass of 3wt% of the mixture. The mixture is stirred for 30 minutes to obtain the compound external electron donor for preparing polypropylene.

[0071] Example 21 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst, 50g of ST70 special white oil, and 40g of pharmaceutical-grade white petrolatum. After stirring at room temperature for 15 minutes, a mixture is obtained. Adjust the temperature of the mixture to 0℃, add L6 silane coupling agent, the amount of which is 1wt% of the mass of the mixture, and stir for 500 minutes to obtain the compound external electron donor for preparing polypropylene.

[0072] Example 22 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 10°C, and L4 silane coupling agent is added at a mass of 2.5wt% of the mixture. The mixture is stirred for 300 minutes to obtain the compound external electron donor for preparing polypropylene.

[0073] Example 23 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 5°C, and L2 silane coupling agent is added at a mass of 0.5wt% of the mixture. The mixture is stirred for 30 minutes to obtain the compound external electron donor for preparing polypropylene.

[0074] Example 24 The preparation method of the compound external electron donor for preparing polypropylene in this embodiment includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 25°C, and L6 silane coupling agent is added at 2wt% of the mass of the mixture. The mixture is stirred for 500 minutes to obtain the compound external electron donor for preparing polypropylene.

[0075] Comparative Example 1 The preparation method of the single external electron donor in this comparative example includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 25℃. No silane coupling agent is added. The mixture is stirred for 600 minutes to obtain the single external electron donor.

[0076] Comparative Example 2 The preparation method of the compound external electron donor in this comparative example includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst and 90g of ST70 special white oil, stir at room temperature for 15 minutes to obtain a mixture, adjust the temperature of the mixture to 25℃, add L7 silane coupling agent, the amount of which is 3wt% of the mass of the mixture, stir for 600min to obtain the compound external electron donor.

[0077] Comparative Example 3 The preparation method of the single external electron donor in this comparative example includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst and 90g of ST70 special white oil, stir at room temperature for 15 minutes to obtain a mixture, adjust the temperature of the mixture to 0℃, do not add silane coupling agent, stir for 500 minutes to obtain a single external electron donor.

[0078] Comparative Example 4 The preparation method of the compound external electron donor in this comparative example includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst and 90g of ST70 special white oil, stir at room temperature for 15 minutes to obtain a mixture, adjust the temperature of the mixture to 0℃, add L7 silane coupling agent, the amount of which is 1.5wt% of the mass of the mixture, stir for 500 minutes to obtain the compound external electron donor.

[0079] Comparative Example 5 The preparation method of the single external electron donor in this comparative example includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 5℃, and no silane coupling agent is added. The mixture is stirred for 400 minutes to obtain the single external electron donor.

[0080] Comparative Example 6 The preparation method of the compound external electron donor in this comparative example includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst and 90g of ST70 special white oil, stir at room temperature for 15 minutes to obtain a mixture, adjust the temperature of the mixture to 5℃, add L7 silane coupling agent, the amount of which is 1.5wt% of the mass of the mixture, stir for 400min to obtain the compound external electron donor.

[0081] Comparative Example 7 The preparation method of the single external electron donor in this comparative example includes the following steps: 10g of polypropylene catalyst and 90g of ST70 special white oil are added to a three-necked flask after nitrogen purging. After stirring at room temperature for 15 minutes, a mixture is obtained. The temperature of the mixture is adjusted to 10℃. No silane coupling agent is added. The mixture is stirred for 300 minutes to obtain the single external electron donor.

[0082] Comparative Example 8 The preparation method of the compound external electron donor in this comparative example includes the following steps: In a three-necked flask after nitrogen purging, add 10g of polypropylene catalyst and 90g of ST70 special white oil, stir at room temperature for 15 minutes to obtain a mixture, adjust the temperature of the mixture to 10℃, add L7 silane coupling agent, the amount of which is 1.5wt% of the mass of the mixture, stir for 300 minutes to obtain the compound external electron donor.

[0083] Application Example 1 The preparation method of impact-resistant polypropylene in this application embodiment includes the following steps: In a dual-reactor tandem polymerization test apparatus, nitrogen and propylene are used to replace the gas in sequence. 2.0 kg of propylene, 4 mL of triethylaluminum hexane solution (concentration of 1 mol / L), 20 mg (based on solid content) of the compounded external electron donor from Example 1, and 2 mL of DIPMS are added to the first reactor. The temperature is raised to the first polymerization temperature of 70°C, and the reaction is carried out for 1 h to obtain an intermediate product. The intermediate product is pressed into the second reactor, and ethylene and propylene (mass ratio of 1:4) are added. Under a pressure of 6 kg, the temperature is raised to the second polymerization temperature of 75°C, and the reaction is carried out for 1 h to obtain impact-resistant polypropylene.

[0084] Application Examples 2-6 The steps are followed according to Application Example 1, except that the composite external electron donors in Examples 2 to 6 are used instead of the composite external electron donors in Example 1.

[0085] Application Comparative Examples 1-2 The steps of Application Example 1 are followed, except that the single external electron donor in Comparative Example 1 and the complex external electron donor in Comparative Example 2 are used instead of the complex external electron donor in Example 1.

[0086] Application Examples 7-12 The preparation method of impact-resistant polypropylene in this application embodiment includes the following steps: In a dual-reactor tandem polymerization test apparatus, nitrogen and propylene are used to replace the gas in sequence. 2.0 kg of propylene, 4 mL of triethylaluminum hexane solution (concentration of 1 mol / L), 20 mg (based on solid content) of the compounded external electron donor from Example 1, and 2 mL of DCPMS are added to the first reactor. The temperature is raised to the first polymerization temperature of 70°C, and the reaction is carried out for 1 h to obtain an intermediate product. The intermediate product is pressed into the second reactor, and ethylene and propylene (mass ratio of 1:3) are added. Under a pressure of 7 kg, the temperature is raised to the second polymerization temperature of 80°C, and the reaction is carried out for 1 h to obtain impact-resistant polypropylene.

[0087] Application Examples 8-12 The steps are followed according to Example 7, except that the composite external electron donors in Examples 8-12 are used instead of the composite external electron donors in Example 7.

[0088] Application Comparative Example 3~4 The steps of Application Example 7 are followed, except that the single external electron donor in Comparative Example 3 and the complex external electron donor in Comparative Example 4 are used instead of the complex external electron donor in Example 7.

[0089] Application Example 13 The preparation method of homopolymer polypropylene in this application embodiment includes the following steps: In a polymerization mold apparatus, the gas is replaced with nitrogen and propylene in sequence, and then 2.0 kg of propylene, 4 mL of triethylaluminum hexane solution (concentration of 1 mol / L), 20 mg (based on solid content) of the compound external electron donor prepared in Example 13 and 2 mL of DIBMS are added; the temperature is raised to 70°C and the reaction is carried out for 2 h to obtain homopolymer polypropylene.

[0090] Application Examples 14-18 The steps are followed according to Application Example 13, except that the composite external electron donors in Examples 14-18 are used instead of the composite external electron donors in Example 13.

[0091] Application Comparative Example 5-6 The steps of Application Example 13 are followed, except that the single external electron donor in Comparative Example 5 and the complex external electron donor in Comparative Example 6 are used instead of the complex external electron donor in Example 13.

[0092] Application Example 19 The preparation method of homopolymer polypropylene in this application example includes the following steps: In a polymerization mold apparatus, the gas is replaced with nitrogen and propylene in sequence, and then 2.0 kg of propylene, 4 mL of triethylaluminum hexane solution (concentration of 1 mol / L), 20 mg (based on solid content) of the compound external electron donor prepared in Example 19 and 2 mL of CHMMS are added; the temperature is raised to 70°C and the reaction is carried out for 2 h to obtain homopolymer polypropylene.

[0093] Application Examples 20-24 The steps are followed according to Application Example 19, except that the composite external electron donors in Examples 20-24 are used instead of the composite external electron donors in Example 1.

[0094] Application Comparative Example 7-8 The steps of Application Example 19 are followed, except that the single external electron donor in Comparative Example 7 and the complex external electron donor in Comparative Example 8 are used instead of the complex external electron donor in Example 19.

[0095] The properties of the polypropylene obtained from the above application examples and comparative examples are shown in Table 1.

[0096] Table 1. Performance Data of Polypropylene

[0097] As shown in Table 1, the composite external electron donors modified with the L1-L6 silane coupling agents described in this invention exhibit excellent polymerization activity in different polymerization systems even at low addition amounts. Compared with the unmodified systems (Comparative Examples 1, 3, 5, and 7), the polymerization activity of this invention is significantly improved; compared with the systems modified with L7 silane coupling agent (Comparative Examples 2, 4, 6, and 8), this invention has significant advantages in both polymerization activity and the overall performance of the products (melt flow rate, flexural modulus, and impact strength). However, if the amount of silane coupling agent added is further increased, the resulting composite external electron donors, when applied to the preparation of polypropylene, result in a decrease in polymerization activity.

[0098] In impact-resistant polypropylene, by selecting DCPMS as another external electron donor, the xylene-soluble content can reach 25-29%, which is significantly higher than the 9-10% of the DIPMS system. It can be seen that the present invention achieves flexible control of the rubber phase content to meet the production needs of polypropylene with different impact resistance grades.

[0099] In homopolymer polypropylene, the xylene soluble content is affected by the type of other external electron donors: when using the DIBMS system, the soluble content is 0, and the product purity is high; when using the CHMMS system, the soluble content is 4%~7%, while giving the material a higher melt flow rate (up to 152.5 g / 10min), which is suitable for fields with strict flow requirements such as thin-walled rapid injection molding.

[0100] The above results show that the compounded external electron donor of the present invention can precisely control the microstructure and macroscopic properties of the polymer over a wide range by synergistically combining with other external electron donors, thereby meeting the diverse needs of different grades of high-performance polypropylene.

[0101] Furthermore, under the same polymerization conditions, the polymer melt flow rate (MFR) of the system using the compound external electron donor of the present invention is significantly improved compared with the unmodified system and the L7 modified system, indicating that the compound external electron donor of the present invention has excellent hydrogen regulation sensitivity and can accurately control the polymer molecular weight over a wide range to meet the production needs of different grades of products.

[0102] In summary, the compounded external electron donor described in this invention exhibits excellent polymerization activity in the polypropylene polymerization reaction. The resulting polypropylene material combines high melt flow rate, good rigidity, and excellent impact resistance, achieving a good balance between processing fluidity and mechanical properties. It can effectively meet the comprehensive performance requirements of high-end plastic products for high-performance polypropylene.

[0103] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0104] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0105] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for preparing a composite external electron donor for polypropylene, characterized in that, The process includes the following steps: mixing polypropylene catalyst, white oil and petrolatum in a mass ratio of (5~50):(25~90):(0~100) to obtain a mixture, then adjusting the temperature of the mixture to 0~25℃, adding silane coupling agent, and stirring to react; The amount of the silane coupling agent added is 0.1~3 wt% of the mass of the mixture; The general structural formula of the silane coupling agent is H2N-R-Si(OC2H5)3 or H2N-R2-NH-R1-Si(OC2H5)3; Wherein, R is selected from C1~C 12 At least one of linear alkylene or phenylene-C6H4-; R1 and R2 are each independently selected from C1 to C2. 12 Straight-chain alkylene groups.

2. The method for preparing a composite external electron donor for polypropylene according to claim 1, characterized in that, The silane coupling agent includes at least one of the following L1 to L6 silane coupling agents: L1 silane coupling agent: structural formula is H2N-CH2-Si(OC2H5)3; L2 silane coupling agent: structural formula H2N-(CH2) 11 -Si(OC2H5)3; L3 silane coupling agent: structural formula is H2N-(CH2)4-Si(OC2H5)3; L4 silane coupling agent: structural formula is H2N-C6H4-Si(OC2H5)3; L5 silane coupling agent: structural formula is H2N-(CH2)6-NH-CH2-Si(OC2H5)3; L6 silane coupling agent: The structural formula is H2N-(CH2)2-NH-(CH2)3-Si(OC2H5)3.

3. The method for preparing a composite external electron donor for polypropylene according to claim 1, characterized in that, The polypropylene catalyst is a Ziegler-Natta type catalyst.

4. The method for preparing a compound external electron donor for polypropylene according to claim 1, characterized in that, The mixing temperature is 10~30℃, and the time is 1~60min.

5. The method for preparing a composite external electron donor for polypropylene according to claim 1, characterized in that, The stirring reaction is carried out at a temperature of 0~25℃ for a time of 5~600 min.

6. A compound external electron donor for preparing polypropylene, characterized in that, It is prepared by the method for preparing a complex external electron donor for polypropylene as described in any one of claims 1 to 5.

7. A polypropylene material, characterized in that, Its raw materials include the compounded external electron donors for preparing polypropylene as described in claim 6.

8. The polypropylene material according to claim 7, characterized in that, The raw materials for the polypropylene material also include other external electron donors; The other external electron donors include at least one of diisopropyldimethoxysilane (DIPMS), dicyclopentyldimethoxysilane (DCPMS), diisobutyldimethoxysilane (DIBMS), and cyclohexylmethyldimethoxysilane (CHMMS).

9. The polypropylene material according to claim 8, characterized in that, The mass ratio of the compound external electron donor to the other external electron donors is 1:(30~150).

10. The polypropylene material according to claim 7, characterized in that, The polypropylene material includes homopolymer polypropylene and / or impact-resistant polypropylene; The homopolymer polypropylene is obtained by homopolymerization of propylene; the impact-resistant polypropylene is obtained by impact copolymerization.

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