High-temperature-resistant impact-resistant polypropylene material as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature-resistant impact-resistant polypropylene material as well as a preparation method and application thereof, and belongs to the technical field of polyolefin production. The preparation method comprises the following steps: sequentially carrying out pre-polymerization, liquid-phase homopolymerization, gas-phase homopolymerization, gas-phase copolymerization, assistant modification and other processes on a propylene monomer, and optimizing parameters of each process section; the polypropylene material can be used for preparing a polypropylene product which is low in MFR (melt flow rate), easy to extrude and mold, good in rigidity, relatively high in relative molecular mass and melt strength, excellent in chemical medicine corrosion resistance and temperature resistance, good in creep resistance and the like, and has the advantages of PVC (polyvinyl chloride), PE (polyethylene) and ABS (acrylonitrile-butadiene-styrene) plates; and the manufacturing requirements of chemical equipment such as chemical storage tanks and pickling tanks can be met.

Description

Technical Field

[0001] The invention relates to the technical field of polyolefin production, and in particular to a high-temperature resistant and impact-resistant polypropylene material and a preparation method and application thereof. Background Art

[0002] As a typical thermoplastic resin, polypropylene is widely used in chemical industry, chemical fiber, construction, light industry, home appliances, automobile and packaging. And its sheet has the advantages of light weight, uniform thickness, smooth surface, good heat resistance, high mechanical strength, excellent chemical stability and electrical insulation, non-toxicity, etc. It can replace stainless steel, wood and other structural materials to make water tanks, packaging containers, automotive parts, etc., and has broad market development prospects; the thickness of polypropylene sheet is generally 2-50mm, and the width does not exceed 2.5m. In recent years, with the development of downstream processing technology, the market demand for polypropylene sheet with thickness > 20mm used in large industrial containers and cutting boards has increased year by year. However, the structural contradictions of polypropylene products are prominent at present, and a large number of high-end or special materials still rely on foreign imports. From the development trend of the polypropylene market in recent years, the market demand for high-flow, high-crystallization, high-impact, high-temperature and oxidation-resistant polypropylene thick sheets is increasing.

[0003] At present, the main plastic sheets on the market are polyvinyl chloride (PVC), polyethylene (PE), acrylonitrile-butadiene-styrene copolymer (ABS), etc.; PVC sheets are low in cost and have strong acid and alkali resistance, but they are not resistant to organic solvents and have poor weather resistance. In addition, hard PVC will become brittle at low temperatures, while soft PVC will harden at low temperatures. It has poor thermal stability and can generally only withstand high temperatures of 81°C. It is easy to degrade to varying degrees under heating conditions, and cannot be completely restored after thermal deformation and stress deformation. PE sheets are resistant to chemical corrosion and low temperature, but have poor UV resistance, a short service life in open air environments, a low flame retardant coefficient, and a high cost. ABS has good low-temperature tolerance and can still retain a certain toughness at -40°C. Its toughness is inferior to PVC and PE, and its impact resistance is relatively high. However, its price is relatively expensive and its heat deformation temperature is low.

[0004] In view of the defects existing in the above-mentioned plastic sheets and the growing demand for high-performance polypropylene products in the current industrial market, developing a polypropylene material that has the advantages of PVC, PE, and ABS sheets is the current research focus in the field of polyolefin production technology. Summary of the invention

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

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

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

[0008] In a second aspect, 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, transferring the product obtained in step S1 into a first reactor and performing a polymerization reaction with propylene and hydrogen;

[0011] S3, transferring the product obtained in step S2 into a second reactor and performing a polymerization reaction with propylene and hydrogen;

[0012] S4, transferring the product obtained in step S3 into a third reactor and performing polymerization reaction with hydrogen, ethylene and propylene;

[0013] S5, performing devolatilization treatment and auxiliary agent modification on the product obtained in step S4 to obtain the high temperature resistant and impact resistant polypropylene material.

[0014] The present invention adopts the method to sequentially subject propylene monomer to prepolymerization, liquid phase homopolymerization, gas phase homopolymerization, gas phase copolymerization and auxiliary agent modification processes, thereby preparing a polypropylene product having low MFR, easy extrusion molding, good rigidity, high relative molecular weight and melt strength, excellent chemical corrosion resistance, temperature resistance and good creep resistance, and can meet the manufacturing requirements of chemical equipment such as chemical storage tanks and pickling tanks; the polypropylene product prepared by the method overcomes the technical difficulty of the current Hypol process that hydrogen cannot be introduced into the first reactor and the melt index of the polypropylene in this section cannot be controlled.

[0015] As a preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, in the 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 method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the Ziegler-Natta catalyst system comprises a main catalyst, a co-catalyst and an electron donor.

[0017] As the most preferred embodiment of the method for preparing 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 Sinopec Catalyst Co., Ltd.

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

[0019] As 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 mono-n-hexylaluminum chloride, monoethylaluminum dichloride, mono-n-butylaluminum dichloride, mono-isobutylaluminum dichloride, and mono-n-hexylaluminum dichloride.

[0020] As the most preferred embodiment of the method for preparing 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] As a more preferred embodiment of the method for preparing 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] As the most preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the diether compound containing an aromatic group is at least one of o-phenylenedimethyl ether, m-phenylenedimethyl ether, p-phenylenedimethyl ether, 1-phenylhexanediol dimethyl ether, and 2-phenylpropylene glycol dimethyl ether.

[0023] As 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 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.

[0024] The inventors have found through a large number of experiments that the present invention can improve the crystallization temperature and heat deformation temperature of the polypropylene material and control the isotacticity of the polypropylene material by prepolymerizing propylene with a specific SAL catalyst, a co-catalyst, and an electron donor.

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

[0026] As a more preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the molar ratio of the SAL catalyst, the co-catalyst, the electron donor and the 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 conducive to improving the performance of the final polypropylene material.

[0027] It should be noted that the molar number of the SAL catalyst is based on the molar number of the titanium element therein.

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

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

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

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

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

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

[0034] The inventors have found through a large number of experiments that when the reaction conditions in the second reactor are within the above range, the polypropylene material prepared in the second reactor has 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] As a preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, in the step S4, the conditions of the polymerization reaction are: the reaction temperature is 74-84° C., and the reaction pressure is 1.10-1.40 MPa.

[0036] As a preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, in the 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] The inventors have found through a large number of experiments that the addition of ethylene in the third reactor can improve the impact strength, tensile yield stress and flexural modulus of the final polypropylene material.

[0038] The inventors also found that when the reaction conditions in the third reactor are within the above range, the polypropylene material prepared in the third reactor has better performance, 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 method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, in step S5, the specific steps of the devolatilization treatment are: continuously introducing nitrogen containing water vapor into the product obtained in step S4 for 1-60 minutes, maintaining the ambient temperature at 90-130°C and the pressure at 25-78KPa.

[0040] As a more preferred embodiment of the method for preparing 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 method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, in the step S5, the specific step of modifying the auxiliary agent is: mixing and granulating the product after the devolatilization treatment with the auxiliary agent in a single screw extruder, and obtaining the high temperature resistant and impact resistant polypropylene material after pelletizing.

[0042] The inventors have found through a large number of experiments that the polypropylene material of the present invention can be modified by additives to improve its crystallization temperature and heat deformation temperature, thereby improving the stability of the final polypropylene material.

[0043] As a more preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the auxiliary agent during the auxiliary agent 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] As the most preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the mass ratio of the auxiliary agent in the product is 1000-20000 ppmw.

[0045] As the most preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the mass ratio of the auxiliary agent in the product is 3000-8000 ppmw.

[0046] As a more preferred embodiment of the method for preparing the high temperature resistant and impact resistant polypropylene material of the present invention, the working temperature of the single screw extruder is 200-300°C.

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

[0048] In a third aspect, the present invention provides a high temperature resistant and impact resistant polypropylene sheet material, which is prepared by the preparation method of the high temperature resistant and impact resistant polypropylene material as described in the second aspect.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The invention establishes a high temperature resistant and impact resistant polypropylene material and a preparation method and application thereof. The propylene monomer is sequentially subjected to processes such as prepolymerization, liquid phase homopolymerization, gas phase homopolymerization, gas phase copolymerization and auxiliary agent modification, and the parameters of each process section are optimized to prepare a polypropylene product having low MFR, easy extrusion molding, good rigidity, high relative molecular weight and melt strength, excellent chemical corrosion resistance, temperature resistance and good creep resistance, and the like. At the same time, the polypropylene product can meet the production requirements of chemical equipment such as chemical storage tanks and pickling tanks. The polypropylene material of the invention can have the advantages of PVC, PE and ABS sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention provides a flow chart for preparing the high temperature resistant and impact resistant polypropylene material. DETAILED DESCRIPTION

[0052] In order to better reflect the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples, its purpose is to explain the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the protection scope of the present invention. The experimental reagents and equipment designed for the implementation of the present invention are all commonly used common reagents and equipment unless otherwise specified.

[0053] Example 1

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

[0055] S1. Add propylene monomer, electron donor, cocatalyst and main catalyst into a prepolymerization kettle, and carry out prepolymerization reaction at a temperature of -0.5°C and a pressure of 44KPa, wherein the main catalyst is a SAL catalyst provided by Beijing Aoda Branch of Sinopec Catalyst Co., Ltd., the cocatalyst is triethylaluminum, the electron donor is 2-phenylpropylene glycol dimethyl ether and tetraethoxysilane, and the molar ratio of 2-phenylpropylene glycol dimethyl ether to tetraethoxysilane is 1:11, and the molar ratio of the SAL catalyst, cocatalyst, electron donor and solvent is 1:15:1:1500;

[0056] S2, transferring the product obtained in step S1 into a first reaction kettle, adding propylene and hydrogen, and reacting 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, transferring the product obtained in step S2 into a second reaction kettle, adding propylene and hydrogen, and reacting 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, transferring the product obtained in step S3 into a third reaction kettle, adding propylene, ethylene and hydrogen, and reacting at a temperature of 81° C. and a pressure of 1.2 MPa, wherein 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, moving the product obtained in step S4 into a de-volatile component section, adding nitrogen containing water vapor, with a nitrogen-water vapor mass ratio of 1:0.002, and staying for 30 minutes under the conditions of a pressure of 66 KPa and a temperature of 115°C;

[0060] S6. Move the product obtained by the devolatilization treatment in step S5 into a single screw extruder, add 2000ppmw of antioxidant 1010, 1500ppmw of antioxidant 168, 800ppmw of calcium stearate HA and 3500ppmw of nucleating agent NAP60, mix and granulate at 270°C, and obtain the high temperature resistant and impact resistant polypropylene material after drying.

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

[0062] Example 2

[0063] The difference between this embodiment and embodiment 1 is that: in the step S1, the prepolymerization reaction is carried out at a temperature of -4°C and a pressure of 116 KPa, and the molar ratio of the SAL catalyst, the co-catalyst, the electron donor and the solvent is 1:150:0.1:100; in the step S2, the reaction is carried out at a temperature of 65°C and a pressure of 3.0 MPa, and the molar ratio of hydrogen to propylene is 0.002:1; in the step S3, the reaction is carried out at a temperature of 75°C and a pressure of 1.9 MPa, and the molar ratio of hydrogen to propylene is 0.002:1; in the step S4, the reaction is carried out at a temperature of 74°C 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] The Mw of the polypropylene material obtained in step S2 of this embodiment is 14.1, Mw / Mn=4.5, isotacticity=98.5%, and MFR is 0.60 g / 10 min; the Mw of the polypropylene material obtained in step S3 is 16.1, Mw / Mn=4.6, isotacticity=96.4%, and MFR is 0.68 g / 10 min; the Mw of the polypropylene material obtained in step S4 is 17.4, Mw / Mn=4.7, isotacticity=76.5%, and MFR is 0.39.

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is that: in the 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, the co-catalyst, the electron donor and the solvent is 1:1:2:3000; in the 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 the 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 the 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] The Mw of the polypropylene material obtained in step S2 of this embodiment is 147, Mw / Mn=4.4, isotacticity=99.0%, and MFR is 0.62 g / 10 min; the Mw of the polypropylene material obtained in step S3 is 15.9, Mw / Mn=4.4, isotacticity=97.0%, and MFR is 0.71 g / 10 min; the Mw of the polypropylene material obtained in step S4 is 17.0, Mw / Mn=4.5, isotacticity=77.0%, and MFR is 0.41.

[0068] Comparative Example 1

[0069] The only difference between this comparative example and Example 1 is that hydrogen is not introduced in step S3, and the remaining steps are consistent with Example 1.

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

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 1 is that in step S6, no auxiliary agent is added, and the product after the devolatilization treatment is directly granulated, and the other steps are consistent with Example 1.

[0073] The Mw of the polypropylene material obtained in step S2 of this comparative example is 157,000, Mw / Mn=4.4, isotacticity=98.7%, and MFR is 0.58 g / 10 min; the Mw of the polypropylene material obtained in step S3 is 159,000, Mw / Mn=4.5, isotacticity=96.7%, and MFR is 0.7 g / 10 min; the Mw of the polypropylene material obtained in step S4 is 172,000, Mw / Mn=4.6, isotacticity=75.0%, and MFR is 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, the co-catalyst, the electron donor and the solvent is 1:15:0.1:1500; the remaining steps are consistent with Example 1.

[0076] The Mw of the polypropylene material obtained in step S2 of this comparative example is 142,000, Mw / Mn=4.9, isotacticity=68.2%, and MFR is 0.71 g / 10 min; the Mw of the polypropylene material obtained in step S3 is 156,000, Mw / Mn=5.1, isotacticity=61.5%, and MFR is 0.7 g / 10 min; the Mw of the polypropylene material obtained in step S4 is 168,000, Mw / Mn=5.3, isotacticity=34.5%, and MFR is 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, and the remaining steps are consistent with Example 1.

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

[0080] Comparative Example 5

[0081] The difference between this comparative example and Example 1 is that: step S3 is not included, the product of the first reactor is directly transferred to the third reactor for reaction, and in step S4, the molar ratio of ethylene to propylene is 1:1.05, and the remaining steps are consistent with Example 1.

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

[0083] Effect example

[0084] Various performance tests were performed on the polypropylene materials prepared by the methods described in Examples 1-3 and Comparative Examples 1-5. 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 Table 1-2, by adjusting the preparation parameters in Examples 1-3 of the present invention, the tensile yield stress of the polypropylene material in Examples 1-3 is ≥36 MPa, the flexural modulus is ≥1500 MPa, the melt index is 0.20-0.40 g / 10 min, the weight average molecular weight Mw is 160,000-190,000, and the simply supported beam notched impact strength (23° C.) is ≥9.5 kJ / m 2 , oxidation induction time ≥ 30min, crystallization temperature ≥ 125°C, load deformation temperature ≥ 95°C, the molar percentage of vinyl in the polymer is 0.2-0.5mol%, and it has the advantages of PVC, PE and ABS sheets, and can meet the production requirements of chemical equipment such as chemical storage tanks and pickling tanks; while the polypropylene products in Comparative Examples 1-5, due to the different preparation methods or process section parameters from the present invention, the performance of the final polypropylene is not as good as that of the embodiments.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A high temperature resistant and impact resistant polypropylene material, characterized in that: The polypropylene material has a melt flow rate of 0.20-0.40 g / 10 min, a crystallization temperature of ≥125° C., a load deformation temperature of ≥95° C., a tensile yield stress of ≥36 MPa, a flexural modulus of ≥1500 MPa, and a simply supported beam notched impact strength (23° C.) of ≥9.5 kJ / m 2 , the weight average molecular weight is 160,000-190,000.

2. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 1, characterized in that: The method comprises the following steps: S1. In a prepolymerization reactor, a prepolymerization reaction is carried out using propylene and a catalyst as raw materials; S2, transferring the product obtained in step S1 into a first reactor and performing a polymerization reaction with propylene and hydrogen; S3, transferring the product obtained in step S2 into a second reactor and performing a polymerization reaction with propylene and hydrogen; S4, transferring the product obtained in step S3 into a third reactor and performing polymerization reaction with hydrogen, ethylene and propylene; S5, performing devolatilization treatment and auxiliary agent modification on the product obtained in step S4 to obtain the high temperature resistant and impact resistant polypropylene material.

3. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 2, characterized in that: In the 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.

4. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 3, characterized in that: Contains at least one of the following: (a) The main catalyst is a SAL type catalyst produced by Beijing Aoda Branch of Sinopec Catalyst Co., Ltd.; (b) the co-catalyst is an alkyl aluminum compound; (c) the electron donor is at least one of a diether compound containing an aromatic ring and an organosilicon compound; (d) The Ziegler-Natta catalyst system further comprises a solvent.

5. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 4, characterized in that: Contains at least one of the following: (e) the co-catalyst is at least one of triethylaluminum-di-n-hexylaluminum chloride, monoethylaluminum dichloride, mono-n-butylaluminum dichloride, mono-isobutylaluminum dichloride, and mono-n-hexylaluminum dichloride; (f) the diether compound containing an aromatic group is at least one of o-phenylenedimethyl ether, m-phenylenedimethyl ether, p-phenylenedimethyl ether, 1-phenylhexanediol dimethyl ether, and 2-phenylpropylene glycol 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.

6. The method for preparing the high temperature resistant and impact resistant polypropylene material according to any one of claims 3 to 5, characterized in that: The molar ratio of the SAL catalyst, the co-catalyst, the electron donor and the solvent is SAL catalyst:co-catalyst:electron donor:solvent=1:1-150:0.1-2:100-3000.

7. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 2, characterized in that: Contains at least one of the following: (i) In step S1, the prepolymerization reaction conditions are: temperature of -4-27°C and pressure of 10-116KPa; (j) In step S2, the polymerization reaction conditions are: temperature of 65-75° C., pressure of 2.65-3.0 MPa, and a molar ratio of hydrogen to propylene of hydrogen:propylene=0.002-0.115:1; (k) In step S3, the reaction conditions of the polymerization reaction are: temperature of 75-85° C., pressure of 1.60-1.90 MPa, and a molar ratio of hydrogen to propylene of hydrogen:propylene=0.002-0.115:1; (l) In step S4, the polymerization reaction conditions are: reaction temperature is 74-84° C., reaction pressure is 1.10-1.40 MPa, 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; (m) In step S5, the specific steps of the devolatilization treatment are: continuously introducing nitrogen containing water vapor into the product obtained in step S4 for 1-60 minutes, maintaining the ambient temperature at 90-130° C. and the pressure at 25-78 KPa.

8. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 2, characterized in that: The auxiliary agent used in the auxiliary agent 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.

9. The method for preparing the high temperature resistant and impact resistant polypropylene material according to claim 8, characterized in that: The mass percentage of the auxiliary agent in the product obtained in step S4 is 1000-20000 ppmw.

10. A high temperature resistant and impact resistant polypropylene sheet, characterized in that: The high temperature resistant and impact resistant polypropylene sheet is prepared by the preparation method of the high temperature resistant and impact resistant polypropylene material as claimed in any one of claims 2 to 9.

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