A high-temperature resistant and impact-resistant polypropylene material, its preparation method and application

Abstract

This invention discloses a high-temperature resistant and impact-resistant polypropylene material, its preparation method, and its applications, belonging to the field of polyolefin production technology. This invention sequentially processes propylene monomers through prepolymerization, liquid-phase homopolymerization, gas-phase homopolymerization, gas-phase copolymerization, and additive modification. By optimizing the parameters of each process stage, a polypropylene product with low molecular weight ratio (MFR), easy extrusion molding, good rigidity, high relative molecular mass and melt strength, excellent chemical corrosion resistance, temperature resistance, and good creep resistance can be prepared. The polypropylene material of this invention possesses the advantages of PVC, PE, and ABS sheets, and can meet the manufacturing requirements of chemical storage tanks, pickling tanks, and other chemical equipment.

Description

Technical Field

[0001] This invention relates to the field of polyolefin production technology, specifically to a high-temperature resistant and impact-resistant polypropylene material, its preparation method, and its application. Background Technology

[0002] Polypropylene, a typical thermoplastic resin, is widely used in chemical, synthetic fiber, construction, light industry, home appliances, automotive, and packaging industries. Its sheets offer advantages such as light weight, uniform thickness, smooth surface, good heat resistance, high mechanical strength, excellent chemical stability and electrical insulation, and non-toxicity. It can replace stainless steel, wood, and other structural materials in the manufacture of water tanks, packaging containers, and automotive parts, showing broad market prospects. Polypropylene sheets are typically 2-50mm thick and no wider than 2.5m. In recent years, with the development of downstream processing technology, the market demand for polypropylene sheets with a thickness greater than 20mm, used in large industrial containers and cut boards, has been increasing year by year. However, the current polypropylene product structure faces significant contradictions, with a large amount of high-end or specialty materials still relying on imports. Looking at the recent polypropylene market development trends, the market demand for thick polypropylene sheets with high fluidity, high crystallinity, high impact resistance, high temperature resistance, and oxidation resistance is increasing.

[0003] Currently, the main types of plastic sheets on the market include polyvinyl chloride (PVC), polyethylene (PE), and acrylonitrile-butadiene-styrene copolymer (ABS). PVC sheets are low in cost and have strong acid and alkali resistance, but they are not resistant to organic solvents, have poor weather resistance, and rigid PVC becomes brittle at low temperatures, while flexible PVC hardens. They also have poor thermal stability, generally only able to withstand temperatures up to 81°C, and are prone to degradation to varying degrees under heating conditions. Furthermore, they cannot fully recover from heat deformation or stress deformation. PE sheets are resistant to chemical corrosion and low temperatures, but have poor UV resistance, a short service life in outdoor environments, a low flame retardant coefficient, and high cost. ABS has good low-temperature resistance, retaining some toughness even at -40°C, although its toughness is inferior to PVC and PE. It has relatively high impact strength, however, it is relatively expensive and has a low heat distortion temperature.

[0004] In response to the defects in the aforementioned plastic sheets and the growing demand for high-performance polypropylene products in the current industrial market, developing a polypropylene material that combines the advantages of PVC, PE, and ABS sheets is a key research focus in the field of polyolefin production technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant and impact-resistant polypropylene material, its preparation method and application. The high-temperature resistant and impact-resistant polypropylene material has a low melt flow rate (MFR), high crystallinity, high temperature resistance, and good rigidity and creep resistance.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a high-temperature resistant and impact-resistant polypropylene material, wherein the polypropylene material has an MFR of 0.20-0.40 g / 10 min, a crystallization temperature ≥125℃, a load deformation temperature ≥95℃, a tensile yield stress ≥36MPa, a flexural modulus ≥1500MPa, and a notched impact strength of a simply supported beam (23℃) ≥9.5kJ / m. 2 The weight-average molecular weight (Mw) is 160,000-190,000.

[0008] Secondly, the present invention provides a method for preparing a high-temperature resistant and impact-resistant polypropylene material, the method comprising the following steps:

[0009] S1. In a prepolymerization reactor, a prepolymerization reaction is carried out using propylene and a catalyst as raw materials;

[0010] S2. The product obtained in step S1 is transferred into the first reactor and polymerized with propylene and hydrogen.

[0011] S3. The product obtained in step S2 is transferred into the second reactor and polymerized with propylene and hydrogen.

[0012] S4. The product obtained in step S3 is transferred into the third reactor and polymerized with hydrogen, ethylene and propylene.

[0013] S5. The product obtained in step S4 is subjected to devolatilization treatment and additive modification to obtain the high-temperature resistant and impact-resistant polypropylene material.

[0014] This invention employs the above-mentioned method to sequentially process propylene monomers through prepolymerization, liquid-phase homopolymerization, gas-phase homopolymerization, gas-phase copolymerization, and additive modification. This process yields polypropylene products with low melt flow rate (MFR), easy extrusion molding, good rigidity, high relative molecular mass and melt strength, excellent resistance to chemical corrosion, temperature resistance, and good creep resistance. These products also meet the manufacturing requirements for chemical storage tanks, pickling tanks, and other chemical equipment. The polypropylene products prepared by this method overcome the technical challenges of the current Hypol process, which cannot introduce hydrogen into the first reactor and thus cannot control the melt flow index of polypropylene in this stage.

[0015] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, in step S1, the catalyst is a Ziegler-Natta catalyst system. The Ziegler-Natta catalyst system used in the present invention has high stereoselectivity and is an excellent directional polymerization catalyst.

[0016] As a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the Ziegler-Natta catalyst system includes a main catalyst, a co-catalyst, and an electron donor.

[0017] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the main catalyst is a SAL type catalyst produced by Beijing Aoda Branch of China Petrochemical Catalyst Co., Ltd.

[0018] In a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the co-catalyst is an alkyl aluminum compound.

[0019] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the co-catalyst is at least one of triethylaluminum dichlorodihexylaluminum, dichloroethylaluminum, dichlorodi-butylaluminum, dichloroisobutylaluminum, and dichlorodihexylaluminum.

[0020] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the co-catalyst is at least one of triethylaluminum, tri-n-butylaluminum, and triisobutylaluminum.

[0021] In a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the electron donor is at least one of a diether compound containing an aromatic ring and an organosilicon compound.

[0022] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the diether compound containing aromatic groups is at least one of o-phenylene ether, m-phenylene ether, p-phenylene dimethyl ether, 1-phenylhexanediol dimethyl ether, and 2-phenylpropanediol dimethyl ether.

[0023] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the organosilicon compound is at least one selected from tetramethoxysilane, tetraethoxysilane, trimethyl-methoxysilane, trimethyl-ethoxysilane, trimethyl-phenoxysilane, dimethyl-dimethoxysilane, dimethyl-diethoxysilane, methyl-tert-butyldimethoxysilane, methyl-isopropyldimethoxysilane, diphenoxy-dimethoxysilane, diphenyl-diethoxysilane, phenyl-trimethoxysilane, phenyl-triethoxysilane, vinyl-trimethoxysilane, cyclohexylmethyl-dimethoxysilane, dicyclopentyl-dimethoxysilane, diisopropyl-dimethoxysilane, and diisobutyl-dimethoxysilane.

[0024] Through numerous experiments, the inventors discovered that by prepolymerizing specific SAL catalysts, co-catalysts, electron donors, and propylene, the present invention can improve the crystallization temperature and heat distortion temperature of the polypropylene material and control its isotacticity.

[0025] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the catalyst in step S1 further includes the solvent n-hexane.

[0026] As a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the molar ratio of SAL catalyst, co-catalyst, electron donor and solvent in the catalyst is SAL catalyst: co-catalyst: electron donor: solvent = 1:1-150:0.1-2:100-3000. The inventors have found through a large number of experiments that when the mass ratio of the catalyst is within the above range, it is more beneficial to improve the performance of the final polypropylene material.

[0027] It should be noted that the molar number of SAL catalyst is calculated based on the molar number of titanium elements in it.

[0028] As a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, in step S1, the conditions for the prepolymerization reaction are: temperature of -4 to 27°C and pressure of 10 to 116 kPa. The inventors have found through a large number of experiments that the polypropylene prepolymer obtained under the above prepolymerization conditions can have better performance.

[0029] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, in step S2, the molar ratio of hydrogen to propylene is hydrogen:propylene = 0.002-0.115:1.

[0030] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the polymerization reaction conditions in step S2 are: temperature of 65-75℃ and pressure of 2.65-3.0MPa.

[0031] Through numerous experiments, the inventors discovered that when the reaction conditions in the first reactor are within the above-mentioned range, the polypropylene material prepared in the first reactor can have better performance, with a Mw of 135,000-165,000, a Mw to number-average molecular weight (Mn) ratio of 4.2-4.8, isotacticity ≥98%, and MFR of 0.55-0.65.

[0032] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the reaction conditions for the polymerization reaction in step S3 are: temperature of 75-85℃ and pressure of 1.60-1.90MPa.

[0033] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, in step S3, the molar ratio of hydrogen to propylene is hydrogen:propylene = 0.002-0.115:1; introducing hydrogen into the second reactor can control the melt index of the polypropylene material, prevent the melt index of polypropylene from being too low and the weight-average molecular weight from being too high, and increase the flexibility of adjusting the polypropylene material.

[0034] Through numerous experiments, the inventors discovered that when the reaction conditions in the second reactor are within the above-mentioned range, the polypropylene material prepared in the second reactor can have better performance, with Mw of 140,000-180,000, Mw / Mn of 4.4-5.0, isotacticity ≥95%, and MFR of 0.65-0.75.

[0035] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the polymerization reaction conditions in step S4 are: reaction temperature of 74-84℃ and reaction pressure of 1.10-1.40MPa.

[0036] In a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, in step S4, the molar ratio of hydrogen to propylene is hydrogen:propylene = 0.002-0.115:1, and the molar ratio of ethylene to propylene is ethylene:propylene = 1:1.00-3.00.

[0037] Through numerous experiments, the inventors discovered that the addition of ethylene to the third reaction vessel can improve the impact strength, tensile yield stress, and flexural modulus of the final polypropylene material.

[0038] The inventors also discovered that when the reaction conditions in the third reactor are within the above range, the polypropylene material prepared in the third reactor has better properties, with Mw of 160,000-190,000, Mw / Mn of 4.6-5.2, isotacticity of 70-78%, and MFR of 0.37-0.45.

[0039] As a preferred embodiment of the preparation method of the high temperature resistant and impact-resistant polypropylene material of the present invention, the specific steps of the devolatilization treatment in step S5 are as follows: nitrogen gas containing water vapor is continuously introduced into the product obtained in step S4 for 1-60 minutes, while maintaining the ambient temperature at 90-130℃ and the pressure at 25-78KPa.

[0040] In a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, during the devolatilization treatment, the mass ratio of nitrogen to water vapor in the nitrogen containing water vapor is nitrogen:water vapor 1:0.002-0.003.

[0041] As a preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the specific steps of the additive modification in step S5 are as follows: the product after devolatilization treatment and the additive are mixed and granulated in a single screw extruder, and the high-temperature resistant and impact-resistant polypropylene material is obtained after pelletizing.

[0042] Through numerous experiments, the inventors discovered that the polypropylene material described in this invention, through modification with additives, can have its crystallization temperature and heat distortion temperature improved, thereby enhancing the stability of the final polypropylene material.

[0043] As a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the additive used in the modification is at least one of antioxidant 1010, antioxidant 168, antioxidant 1330, antioxidant 1076, synthetic hydrotalcite AC207, synthetic hydrotalcite DHT-4A, nucleating agent M1128, nucleating agent VP101B, nucleating agent NAP60, nucleating agent VP101T, and calcium stearate.

[0044] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the mass ratio of the additive in the product is 1000-20000 ppmw.

[0045] In the most preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the mass ratio of the additives in the product is 3000-8000 ppmw.

[0046] As a more preferred embodiment of the preparation method of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the operating temperature of the single screw extruder is 200-300℃.

[0047] In the preparation process of the high-temperature resistant and impact-resistant polypropylene material of the present invention, the limitation of parameters in each of the above-mentioned reaction vessels is very important. Each link is interconnected and directly affects the performance of the final polypropylene material.

[0048] Thirdly, the present invention provides a high-temperature resistant and impact-resistant polypropylene sheet, which is prepared by the method for preparing high-temperature resistant and impact-resistant polypropylene material as described in the second aspect.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] This invention establishes a high-temperature resistant and impact-resistant polypropylene material, its preparation method, and its application. Propylene monomer is sequentially processed through prepolymerization, liquid-phase homopolymerization, gas-phase homopolymerization, gas-phase copolymerization, and additive modification. By optimizing the parameters of each process stage, a polypropylene product with low molecular weight ratio (MFR), easy extrusion molding, good rigidity, high relative molecular mass and melt strength, excellent chemical corrosion resistance, temperature resistance, and good creep resistance can be prepared. This material can also meet the manufacturing requirements of chemical storage tanks, pickling tanks, and other chemical equipment. The polypropylene material of this invention possesses the advantages of PVC, PE, and ABS sheets. Attached Figure Description

[0051] Figure 1 This is a flowchart illustrating the preparation process of the high-temperature resistant and impact-resistant polypropylene material described in this invention. Detailed Implementation

[0052] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to explain the content of this invention in detail, not to limit it. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and equipment designed for implementation of this invention are all commonly used reagents and equipment.

[0053] Example 1

[0054] This embodiment provides a method for preparing a high-temperature resistant and impact-resistant polypropylene material, the method comprising the following steps:

[0055] S1. Propylene monomer, electron donor, co-catalyst and main catalyst are added to a prepolymerization reactor and prepolymerization reaction is carried out at a temperature of -0.5℃ and a pressure of 44KPa. The main catalyst is SAL catalyst provided by Beijing Aoda Branch of Sinopec Catalyst Co., Ltd., the co-catalyst is triethylaluminum, the electron donor is 2-phenylpropanediol dimethyl ether and tetraethoxysilane, and the molar ratio of 2-phenylpropanediol dimethyl ether and tetraethoxysilane is 1:11. The molar ratio of SAL catalyst, co-catalyst, electron donor and solvent is 1:15:1:1500.

[0056] S2. The product obtained in step S1 is transferred into the first reaction vessel, propylene and hydrogen are added, and the reaction is carried out at a temperature of 70°C and a pressure of 2.89 MPa, wherein the molar ratio of hydrogen to propylene is 0.012:1.

[0057] S3. The product obtained in step S2 is transferred into the second reaction vessel, propylene and hydrogen are added, and the reaction is carried out at a temperature of 80°C and a pressure of 1.76 MPa, wherein the molar ratio of hydrogen to propylene is 0.012:1.

[0058] S4. The product obtained in step S3 is transferred into the third reaction vessel, propylene, ethylene and hydrogen are added, and the reaction is carried out at a temperature of 81°C and a pressure of 1.2 MPa. The molar ratio of hydrogen to propylene is 0.004:1, and the molar ratio of ethylene to propylene is 1:1.84.

[0059] S5. Transfer the product obtained in step S4 into the devolatileization section, add nitrogen containing water vapor, the mass ratio of nitrogen to water vapor is 1:0.002, and let it stand for 30 minutes at a pressure of 66 kPa and a temperature of 115°C.

[0060] S6. The product from the devolatilization treatment in step S5 is transferred into a single-screw extruder, and 2000 ppmw antioxidant 1010, 1500 ppmw antioxidant 168, 800 ppmw calcium stearate HA and 3500 ppmw nucleating agent NAP60 are added. The mixture is granulated at 270°C and dried to obtain the high-temperature resistant and impact-resistant polypropylene material.

[0061] In this embodiment, the polypropylene material obtained in step S2 has a Mw of 157,000, Mw / Mn = 4.4, isotacticity = 98.7%, and MFR of 0.58 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 159,000, Mw / Mn = 4.5, isotacticity = 96.7%, and MFR of 0.7 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 172,000, Mw / Mn = 4.6, isotacticity = 75.0%, and MFR of 0.4 g / 10 min.

[0062] Example 2

[0063] The only difference between this embodiment and Example 1 is that: in step S1, the prepolymerization reaction is carried out at a temperature of -4℃ and a pressure of 116 kPa, and the molar ratio of the SAL catalyst, co-catalyst, electron donor, and solvent is 1:150:0.1:100; in step S2, the reaction is carried out at a temperature of 65℃ and a pressure of 3.0 MPa, and the molar ratio of hydrogen to propylene is 0.002:1; in step S3, the reaction is carried out at a temperature of 75℃ and a pressure of 1.9 MPa, and the molar ratio of hydrogen to propylene is 0.002:1; in step S4, the reaction is carried out at a temperature of 74℃ and a pressure of 1.4 MPa, the molar ratio of hydrogen to propylene is 0.002:1, and the molar ratio of ethylene to propylene is 1:1.

[0064] In this embodiment, the polypropylene material obtained in step S2 has a Mw of 14.1, Mw / Mn = 4.5, isotacticity = 98.5%, and MFR of 0.60 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 16.1, Mw / Mn = 4.6, isotacticity = 96.4%, and MFR of 0.68 g / 10 min; and the polypropylene material obtained in step S4 has a Mw of 17.4, Mw / Mn = 4.7, isotacticity = 76.5%, and MFR of 0.39.

[0065] Example 3

[0066] The only difference between this embodiment and Example 1 is that: in step S1, the prepolymerization reaction is carried out at a temperature of 27°C and a pressure of 10 kPa, and the molar ratio of the SAL catalyst, co-catalyst, electron donor, and solvent is 1:1:2:3000; in step S2, the reaction is carried out at a temperature of 75°C and a pressure of 2.6 MPa, and the molar ratio of hydrogen to propylene is 0.115:1; in step S3, the reaction is carried out at a temperature of 85°C and a pressure of 1.6 MPa, and the molar ratio of hydrogen to propylene is 0.115:1; in step S4, the reaction is carried out at a temperature of 84°C and a pressure of 1.1 MPa, the molar ratio of hydrogen to propylene is 0.115:1, and the molar ratio of ethylene to propylene is 1:3.

[0067] In this embodiment, the polypropylene material obtained in step S2 has a Mw of 147, Mw / Mn = 4.4, isotacticity = 99.0%, and MFR of 0.62 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 15.9, Mw / Mn = 4.4, isotacticity = 97.0%, and MFR of 0.71 g / 10 min; and the polypropylene material obtained in step S4 has a Mw of 17.0, Mw / Mn = 4.5, isotacticity = 77.0%, and MFR of 0.41.

[0068] Comparative Example 1

[0069] The only difference between this comparative example and Example 1 is that hydrogen gas was not introduced in step S3; all other steps are the same as in Example 1.

[0070] The polypropylene material obtained in step S2 of this comparative example has a Mw of 160,000, Mw / Mn = 4.4, isotacticity = 98.5%, and MFR of 0.55 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 184,000, Mw / Mn = 4.6, isotacticity = 98%, and MFR of 0.46 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 210,000, Mw / Mn = 4.3, isotacticity = 78.0%, and MFR of 0.24 g / 10 min.

[0071] Comparative Example 2

[0072] The only difference between this comparative example and Example 1 is that in step S6, no additives were added, and the product after devolatilization was directly granulated. All other steps are the same as in Example 1.

[0073] The polypropylene material obtained in step S2 of this comparative example has a Mw of 157,000, Mw / Mn = 4.4, isotacticity = 98.7%, and MFR of 0.58 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 159,000, Mw / Mn = 4.5, isotacticity = 96.7%, and MFR of 0.7 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 172,000, Mw / Mn = 4.6, isotacticity = 75.0%, and MFR of 0.4 g / 10 min.

[0074] Comparative Example 3

[0075] The only difference between this comparative example and Example 1 is that in step S1, the molar ratio of the SAL catalyst, co-catalyst, electron donor, and solvent is 1:15:0.1:1500; the remaining steps are the same as in Example 1.

[0076] The polypropylene material obtained in step S2 of this comparative example has a Mw of 142,000, Mw / Mn = 4.9, isotacticity = 68.2%, and MFR of 0.71 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 156,000, Mw / Mn = 5.1, isotacticity = 61.5%, and MFR of 0.7 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 168,000, Mw / Mn = 5.3, isotacticity = 34.5%, and MFR of 0.47 g / 10 min.

[0077] Comparative Example 4

[0078] The only difference between this comparative example and Example 1 is that in step S4, the molar ratio of ethylene to propylene is 1:0.05; all other steps are the same as in Example 1.

[0079] The polypropylene material obtained in step S2 of this comparative example has a Mw of 159,000, Mw / Mn = 4.4, isotacticity = 98.9%, and MFR of 0.56 g / 10 min; the polypropylene material obtained in step S3 has a Mw of 158,000, Mw / Mn = 4.5, isotacticity = 97%, and MFR of 0.69 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 175,000, Mw / Mn = 4.4, isotacticity = 98%, and MFR of 0.37 g / 10 min.

[0080] Comparative Example 5

[0081] The only difference between this comparative example and Example 1 is that step S3 is omitted, and the product from the first reactor is directly transferred to the third reactor for reaction. In step S4, the molar ratio of ethylene to propylene is 1:1.05. All other steps are the same as in Example 1.

[0082] The polypropylene material obtained in step S2 of this comparative example has a Mw of 156,000, Mw / Mn = 4.4, isotacticity = 97.8%, and MFR of 0.59 g / 10 min; the polypropylene material obtained in step S4 has a Mw of 159,000, Mw / Mn = 5.5, isotacticity = 46%, and MFR of 0.7 g / 10 min.

[0083] Example of effect

[0084] The polypropylene materials prepared by the methods described in Examples 1-3 and Comparative Examples 1-5 were subjected to various performance tests, and the test results are shown in Tables 1 and 2 below.

[0085] Table 1

[0086]

[0087]

[0088] Table 2

[0089]

[0090] As can be seen from Tables 1-2, by adjusting the preparation parameters, Examples 1-3 of the present invention achieve the following results: tensile yield stress ≥36MPa, flexural modulus ≥1500MPa, melt flow index 0.20-0.40g / 10min, weight-average molecular weight Mw 160,000-190,000, and notched impact strength of simply supported beam (23℃) ≥9.5kJ / m². 2 The oxidation induction time is ≥30 min, the crystallization temperature is ≥125℃, the load deformation temperature is ≥95℃, and the molar percentage of vinyl in the polymer is 0.2-0.5 mol%. It has the advantages of PVC, PE and ABS sheets and can meet the manufacturing requirements of chemical storage tanks, pickling tanks and other chemical equipment. However, the polypropylene products in Comparative Examples 1-5 have different preparation methods or process parameters than the present invention, resulting in the final polypropylene performance being inferior to that of the examples.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-temperature resistant and impact-resistant polypropylene material, characterized in that, The preparation method of the high-temperature resistant and impact-resistant polypropylene material includes the following steps: S1. In a prepolymerization reactor, a prepolymerization reaction is carried out using propylene and a catalyst as raw materials; S2. The product obtained in step S1 is transferred into the first reactor and polymerized with propylene and hydrogen. S3. The product obtained in step S2 is transferred into the second reactor and polymerized with propylene and hydrogen. S4. The product obtained in step S3 is transferred into the third reactor and polymerized with hydrogen, ethylene and propylene. S5. The product obtained in step S4 is subjected to devolatilization treatment and additive modification to obtain the high temperature resistant and impact-resistant polypropylene material. In step S1, the catalyst is a Ziegler-Natta catalyst system; wherein, the Ziegler-Natta catalyst system comprises a main catalyst, a co-catalyst, and an electron donor; The main catalyst is a SAL-type catalyst produced by Beijing Aoda Branch of Sinopec Catalyst Co., Ltd.; the co-catalyst is an alkylaluminum compound; the electron donor is at least one of an aromatic ring-containing diether compound and an organosilicon compound; the Ziegler-Natta catalyst system also contains a solvent; the molar ratio of the SAL catalyst, co-catalyst, electron donor and solvent is SAL catalyst: co-catalyst: electron donor: solvent = 1:1-150:0.1-2:100-3000; In step S1, the prepolymerization reaction conditions are: temperature -4 to 27°C and pressure 10 to 116 kPa; in step S2, the polymerization reaction conditions are: temperature 65 to 75°C and pressure 2.65 to 3.0 MPa, with a hydrogen to propylene molar ratio of hydrogen:propylene = 0.002 to 0.115:1; in step S3, the polymerization reaction conditions are: temperature 75 to 85°C and pressure 1.60 to 1.90 MPa, with a hydrogen to propylene molar ratio of hydrogen:propylene = 0.002 to 0.

11. 5:1; In step S4, the polymerization reaction conditions are: reaction temperature 74-84℃, reaction pressure 1.10-1.40MPa, molar ratio of hydrogen to propylene of hydrogen:propylene = 0.002-0.115:1, and molar ratio of ethylene to propylene of ethylene:propylene = 1:1.00-3.00; In step S5, the specific steps of the devolatilization treatment are: continuously introducing nitrogen gas containing water vapor into the product obtained in step S4 for 1-60 minutes, maintaining an ambient temperature of 90-130℃ and a pressure of 25-78KPa; The polypropylene material has a melt flow rate of 0.20-0.40 g / 10 min, a crystallization temperature of ≥125℃, a load deformation temperature of ≥95℃, a tensile yield stress of ≥36 MPa, a flexural modulus of ≥1500 MPa, a notched impact strength of a simply supported beam at 23℃ of ≥9.5 kJ / m2, and a weight-average molecular weight of 160,000-190,000.

2. The high-temperature resistant and impact-resistant polypropylene material as described in claim 1, characterized in that, Includes at least one of the following: (e) The co-catalyst is at least one of triethylaluminum di-n-hexylaluminum chloride, dichloroethylaluminum, dichloro-n-butylaluminum, dichloro-isobutylaluminum, and dichloro-n-hexylaluminum; (f) The aromatic diether compound is at least one of o-phenylene dimethyl ether, m-phenylene dimethyl ether, p-phenylene dimethyl ether, 1-phenylhexanediol dimethyl ether, and 2-phenylpropanediol dimethyl ether; (g) The organosilicon compound is at least one of tetramethoxysilane, tetraethoxysilane, trimethyl-methoxysilane, trimethyl-ethoxysilane, trimethyl-phenoxysilane, dimethyl-dimethoxysilane, dimethyl-diethoxysilane, methyl-tert-butyldimethoxysilane, methyl-isopropyldimethoxysilane, diphenoxy-dimethoxysilane, diphenyl-diethoxysilane, phenyl-trimethoxysilane, phenyl-triethoxysilane, vinyl-trimethoxysilane, cyclohexylmethyl-dimethoxysilane, dicyclopentyl-dimethoxysilane, diisopropyl-dimethoxysilane, and diisobutyl-dimethoxysilane. (h) The solvent is n-hexane.

3. The high-temperature resistant and impact-resistant polypropylene material as described in claim 1, characterized in that, The additive used in the modification process is at least one of the following: antioxidant 1010, antioxidant 168, antioxidant 1330, antioxidant 1076, synthetic hydrotalcite AC207, synthetic hydrotalcite DHT-4A, nucleating agent M1128, nucleating agent VP101B, nucleating agent NAP60, nucleating agent VP101T, and calcium stearate.

4. The high-temperature resistant and impact-resistant polypropylene material as described in claim 3, characterized in that, The mass percentage of the adjuvant in the product obtained in step S4 is 1000-20000 ppmw.

5. A high-temperature resistant and impact-resistant polypropylene sheet, characterized in that, The high-temperature resistant and impact-resistant polypropylene sheet includes the high-temperature resistant and impact-resistant polypropylene material according to any one of claims 2-4.

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