Polypropylene material as well as preparation method and application thereof

Abstract

The invention relates to a polypropylene material as well as a preparation method and application thereof. The polypropylene material comprises the following components: co-polypropylene, the co-polypropylene comprises a continuous phase formed by a homo-polypropylene chain segment and a rubber phase formed by an ethylene-propylene copolymer chain segment; the isotacticity of the homo-polypropylene chain segment is 98 to 99 percent; the mass percentage content of the rubber phase in the co-polypropylene is 10-15%; the mass percentage content of the ethylene unit in the rubber phase is 20-40%; the melt index of the polypropylene material is 60 to 100g / 10min. Through component design, the polypropylene material provided by the invention has the characteristics of high melt index, high modulus and high impact resistance, and can meet the application requirements of large thin-wall workpieces.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a polypropylene material, its preparation method, and its application. Background Technology

[0002] Currently, improving the melt flow index, modulus, and impact resistance of polypropylene resin is an urgent need for polypropylene materials in various fields. Improved polypropylene flowability can reduce processing temperature, injection pressure, and clamping force during product manufacturing, thereby reducing energy consumption, shortening the product molding cycle, and significantly increasing product output, meeting the demands of large-sized products and high-speed injection molding. Furthermore, using high-flow polypropylene allows for the injection molding of thin-walled products, reducing raw material usage and lowering costs.

[0003] The synthesis of impact-resistant copolymer polypropylene typically involves two steps: first, the synthesis of a homopolymer matrix, and second, the synthesis of a rubber phase. To achieve high flowability in impact-resistant polypropylene, a more fluid homopolymer matrix needs to be synthesized, followed by the synthesis of a higher molecular weight rubber phase on top of this matrix. During the production of the homopolymer matrix, a large amount of hydrogen is required as a molecular weight regulator to ensure a high melt index for the homopolymer polypropylene. However, excessively high hydrogen concentrations in the reaction system inhibit the growth of the rubber phase. Lower molecular weight rubber phases tend to aggregate within the polypropylene matrix, while excessively large rubber phases fail to provide toughening. Increasing the rubber phase content is a common choice to improve impact strength, but this usually results in a decrease in modulus. Therefore, producing polypropylene materials that combine high melt index, high modulus, and high impact resistance is extremely challenging.

[0004] CN119954998A discloses a method for preparing a high melt index and impact-resistant polypropylene material for automotive interiors. By adding two external electron donors during the reaction process, a polypropylene material with a wide molecular weight distribution, high flowability, high rigidity, and high impact resistance is obtained. However, the addition of multiple types and large doses of external electron donors reduces catalyst activity and hydrogen sensitivity, making it difficult to control the balance of material flowability, modulus, and impact performance during mass production. CN117186286A uses a Spheripol device with two loop reactors and one gas-phase reactor to prepare a high-flowability and high-impact polypropylene material with a melt index of 20-35 g / 10 min. Its flowability is insufficient to meet the flowability requirements of large, thin-walled parts. CN119899303A discloses a high-flowability and high-impact transparent polypropylene material. However, this polypropylene material has a low modulus and cannot meet the rigidity requirements of large, thin-walled parts.

[0005] Therefore, it is imperative to develop a polypropylene material with high melt index, high modulus, and high impact resistance to meet the needs of large, thin-walled parts in industries such as automobiles and home appliances. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a polypropylene material, its preparation method and application, and through the design of components, the polypropylene material has the characteristics of high melt index, high modulus and high impact resistance.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a polypropylene material, wherein the components of the polypropylene material include copolymerized polypropylene; the copolymerized polypropylene includes a continuous phase formed by homopolymerized polypropylene segments and a rubber phase formed by ethylene-propylene copolymer segments; the isotacticity of the homopolymerized polypropylene segments is 98-99%; the mass percentage content of the rubber phase in the copolymerized polypropylene is 10-15%; the mass percentage content of ethylene units in the rubber phase is 20-40%; and the melt index of the polypropylene material is 60-100 g / 10 min.

[0008] The polypropylene material provided by this invention has a high degree of isotacticity in the homopolymer polypropylene segments of the copolymer polypropylene, and by controlling the composition of its rubber phase segments and the mass percentage of the rubber phase, a polypropylene material with high melt index, high modulus, and high impact is obtained.

[0009] The isotacticity of the homopolymer polypropylene segments is 98-99%, for example, it can be 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, etc.

[0010] In this invention, the isotacticity of the homopolymer polypropylene segments is obtained according to GB / T2412-2008.

[0011] The mass percentage of the rubber phase in the copolymerized polypropylene is 10-15%, for example, it can be 10.2%, 10.5%, 10.8%, 11%, 11.2%, 11.5%, 11.8%, 12%, 12.2%, 12.5%, 12.8%, 13%, 13.2%, 13.5%, 13.8%, 14%, 14.2%, 14.5%, 14.8%, etc.

[0012] The mass percentage of ethylene units in the rubber phase is 20-40%, for example, it can be 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, etc.

[0013] The melt flow index of the polypropylene material is 60-100 g / 10 min, for example, it can be 62 g / 10 min, 65 g / 10 min, 68 g / 10 min, 70 g / 10 min, 72 g / 10 min, 75 g / 10 min, 78 g / 10 min, 80 g / 10 min, 82 g / 10 min, 85 g / 10 min, 88 g / 10 min, 90 g / 10 min, 92 g / 10 min, 95 g / 10 min, 98 g / 10 min, etc.

[0014] In this invention, the melt flow index of the polypropylene material is obtained according to GB / T 3682.1-2018.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0016] As a preferred technical solution, the mass percentage of ethylene units in the rubber phase is 30-36%.

[0017] Preferably, the melt flow index of the polypropylene material is 65-100 g / 10 min.

[0018] Preferably, the polypropylene material has a cantilever beam impact strength >6 kJ / m at 23°C. 2 For example, it can be 6.2 kJ / m 2 6.4 kJ / m 2 6.6kJ / m 2 6.8kJ / m 2 7kJ / m 2 7.2kJ / m 2 7.4 kJ / m 2 7.6 kJ / m 2 7.8kJ / m 2 8kJ / m 2 8.2kJ / m 2 8.4 kJ / m 2 8.6kJ / m 2 8.8kJ / m 2 Further optimization was performed using 7-8.5 kJ / m 2 .

[0019] In this invention, the cantilever beam impact strength of the polypropylene material is obtained according to GB / T1843-2008.

[0020] Preferably, the flexural modulus of the polypropylene material is ≥1600MPa, for example, it can be 1620MPa, 1640MPa, 1660MPa, 1680MPa, 1700MPa, 1720MPa, 1780MPa, 1800MPa, etc., and more preferably 1650-1800MPa.

[0021] In this invention, the flexural modulus of the polypropylene material is obtained by testing according to GB / T 9341-2008.

[0022] Preferably, the polypropylene material further includes a nucleating agent.

[0023] Preferably, the nucleating agent comprises any one or a combination of at least two of calcium hexahydrophthalate, aluminum p-tert-butylbenzoate, sodium 2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, or basic aluminum 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate).

[0024] Preferably, the mass ratio of the copolymerized polypropylene to the nucleating agent is (1000-2000):1, for example, it can be 1050:1, 1100:1, 1150:1, 1200:1, 1250:1, 1300:1, 1350:1, 1400:1, 1450:1, 1500:1, 1550:1, 1600:1, 1650:1, 1700:1, 1750:1, 1800:1, 1850:1, 1900:1, 1950:1, etc.

[0025] Preferably, the polypropylene material further includes an antioxidant.

[0026] Preferably, the antioxidants include antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), antioxidant 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), antioxidant 1790 (1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione), and antioxidant 31. The antioxidant 9228 (3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane), antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), or antioxidant 626 (bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite).

[0027] Preferably, the mass ratio of the copolymer polypropylene to the antioxidant is (500-1000):1, for example, it can be 550:1, 600:1, 650:1, 700:1, 750:1, 800:1, 850:1, 900:1, 950:1, etc.

[0028] Preferably, the polypropylene material further includes an acid absorber.

[0029] Preferably, the acid absorbent comprises calcium stearate and / or hydrotalcite.

[0030] Preferably, the mass ratio of the copolymer polypropylene to the acid scavenger is (1400-2000):1, for example, it can be 1450:1, 1500:1, 1550:1, 1600:1, 1650:1, 1700:1, 1750:1, 1800:1, 1850:1, 1900:1, 1950:1, etc.

[0031] In a second aspect, the present invention provides a method for preparing a polypropylene material as described in the first aspect, the method comprising the following steps: (1) Propylene is mixed with the catalyst and then subjected to a prepolymerization reaction to obtain a prepolymerization slurry; the catalyst includes a main catalyst and a cocatalyst; the main catalyst is a Ziegler-Natta catalyst; the Ziegler-Natta catalyst has an internal electron donor supported on its internal support; the internal electron donor includes any one or a combination of at least two of 9,9-bis(methoxymethyl)fluorene, 9,9-bis(methyl benzoate)fluorene, 3,3-bismethoxymethyl-2,6-dimethylheptane or cyclobutyl-1,1-diethanol dimethyl ether; the Dv(0.5) of the Ziegler-Natta catalyst is 50-60 μm; the multiplication factor of the prepolymerization reaction is 50-100 times; (2) The prepolymerized slurry, propylene and hydrogen are polymerized in a first loop reactor and a second loop reactor connected in series to obtain homopolymer polypropylene; the hydrogen concentration in the first loop reactor is 3000-5000ppm; the hydrogen concentration in the second loop reactor is 4000-6000ppm; the total time of the polymerization reaction is 25-35min. (3) The homopolymer polypropylene, propylene and ethylene are copolymerized to obtain copolymer polypropylene; the molar ratio of ethylene to propylene in this step is (0.1-0.2):1; (4) The copolymer polypropylene is extruded to obtain the polypropylene material.

[0032] In the preparation method of polypropylene material provided by the present invention, no external electron donor is used in the catalyst, which avoids the loss of catalyst active sites and the reduction of catalyst hydrogen sensitivity due to the introduction of external electron donor. At the same time, the specific internal electron donor has high hydrogen sensitivity and high stereoselectivity, which can not only realize the production of homopolymer polypropylene with high melt index and high isotacticity at a lower hydrogen concentration, but also reduce the degree of prepolymerization and shorten the polymerization reaction time.

[0033] The Ziegler-Natta catalyst has a Dv(0.5) of 50-60 μm, for example, 51 μm, 52 μm, 53 μm, 54 μm, 55 μm, 56 μm, 57 μm, 58 μm, 59 μm, 60 μm, etc. This invention selects a large-particle-size spherical catalyst; the larger particle size implies a stronger ability to shift catalytic activity backward, thus retaining more catalytic activity for copolymerization.

[0034] In this invention, the Ziegler-Natta catalyst is a TiCl4 / MgCl2 supported high-efficiency polypropylene catalyst with a supporting monomer; its Dv(0.5) is obtained according to ISO 13320:2009.

[0035] The multiplication factor of the prepolymerization reaction is 50-100 times, for example, it can be 55 times, 60 times, 65 times, 70 times, 75 times, 80 times, 85 times, 90 times, 95 times, etc.

[0036] The hydrogen concentration in the first loop reactor is 3000-5000ppm, for example, it can be 3200ppm, 3400ppm, 3600ppm, 3800ppm, 4000ppm, 4200ppm, 4400ppm, 4600ppm, 4800ppm, etc.

[0037] The hydrogen concentration in the second loop reactor is 4000-6000 ppm, for example, it can be 4200 ppm, 4400 ppm, 4600 ppm, 4800 ppm, 5000 ppm, 5200 ppm, 5400 ppm, 5600 ppm, 5800 ppm, etc.

[0038] The hydrogen concentrations mentioned in this invention are all calculated based on the mass of propylene in step (2) being 100%.

[0039] In this invention, the hydrogen concentration in the first loop reactor and the hydrogen concentration in the second loop reactor are obtained by gas chromatography.

[0040] The total time for the polymerization reaction in step (2) is 25-35 min, for example, it can be 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min, etc.; the total time for the polymerization reaction in this invention is the total time for the material to undergo polymerization reaction in the first loop reactor and the second loop reactor.

[0041] The molar ratio of ethylene to propylene is (0.1-0.2):1, for example, it can be 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1, 0.16:1, 0.17:1, 0.18:1, 0.19:1, etc.

[0042] Preferably, the main catalyst is a heterogeneous spherical Ziegler-Natta catalyst.

[0043] Preferably, the mass percentage of the internal electron donor in the main catalyst is 5-10%, for example, it can be 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

[0044] Preferably, the co-catalyst comprises alkylaluminum.

[0045] Preferably, the alkylaluminum comprises triethylaluminum.

[0046] Preferably, the molar ratio of Ti to Al in the catalyst is 1:(5-50), for example, it can be 1:6, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, etc.

[0047] Preferably, the catalyst is pre-complexed before the prepolymerization reaction is carried out.

[0048] Preferably, the pre-complexation includes the following steps: (S1) Mix the main catalyst, white oil and petrolatum at 65-75°C, and then cool to 9-11°C to obtain the main catalyst paste; (S2) The main catalyst paste and the co-catalyst are pre-complexed to obtain a pre-complexed catalyst.

[0049] Preferably, the pre-complexation temperature is 9-15℃, for example, it can be 9.5℃, 10℃, 10.5℃, 11℃, 11.5℃, 12℃, 12.5℃, 13℃, 13.5℃, 14℃, 14.5℃, etc.

[0050] Preferably, the pre-complexation time is 30-60 min, for example, it can be 32 min, 35 min, 38 min, 40 min, 42 min, 45 min, 48 min, 50 min, 52 min, 55 min, 58 min, etc.

[0051] Preferably, the ratio of the main catalyst, white oil and petrolatum is 1 kg: (1.45-1.55) L: (2.95-3.05) L.

[0052] Preferably, the temperature of the prepolymerization reaction is 10-20℃, for example, it can be 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, etc.

[0053] Preferably, the pressure of the prepolymerization reaction is 3-4 MPa, for example, it can be 3.1 MPa, 3.2 MPa, 3.3 MPa, 3.4 MPa, 3.5 MPa, 3.6 MPa, 3.7 MPa, 3.8 MPa, 3.9 MPa, etc.

[0054] Preferably, the prepolymerization reaction time is 10-20 min, for example, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, etc.

[0055] Preferably, the polymerization reaction is liquid-phase bulk polymerization.

[0056] Preferably, the reaction temperatures in the first loop reactor and the second loop reactor are each independently 65-70°C, for example, 65.5°C, 66°C, 66.5°C, 67°C, 67.5°C, 68°C, 68.5°C, 69°C, 69.5°C, etc.

[0057] Preferably, the reaction pressure in the first loop reactor and the second loop reactor is independently 3.2-3.8 MPa, for example, it can be 3.25 MPa, 3.3 MPa, 3.35 MPa, 3.4 MPa, 3.45 MPa, 3.5 MPa, 3.55 MPa, 3.6 MPa, 3.65 MPa, 3.7 MPa, 3.75 MPa, etc.

[0058] Preferably, the melt index of the homopolymer polypropylene is 100-200 g / 10 min, for example, it can be 110 g / 10 min, 115 g / 10 min, 120 g / 10 min, 125 g / 10 min, 130 g / 10 min, 135 g / 10 min, 140 g / 10 min, 145 g / 10 min, 150 g / 10 min, 155 g / 10 min, 160 g / 10 min, 165 g / 10 min, 170 g / 10 min, 175 g / 10 min, 180 g / 10 min, 185 g / 10 min, 190 g / 10 min, 195 g / 10 min, etc.

[0059] In this invention, the melt index of the homopolymer polypropylene is obtained according to GB / T 3682.1-2018.

[0060] Preferably, the copolymerization temperature is 66-70℃, for example, it can be 66.5℃, 67℃, 67.5℃, 68℃, 68.5℃, 69℃, 69.5℃, etc.

[0061] Preferably, the copolymerization time is 30-50 min, for example, it can be 32 min, 34 min, 36 min, 38 min, 40 min, 42 min, 44 min, 46 min, 48 min, etc.

[0062] Preferably, the copolymerization pressure is 1.55-1.65 MPa, for example, it can be 1.56 MPa, 1.57 MPa, 1.58 MPa, 1.59 MPa, 1.6 MPa, 1.61 MPa, 1.62 MPa, 1.63 MPa, 1.64 MPa, etc.

[0063] Preferably, the copolymerization is carried out in a vertical gas-phase reactor.

[0064] Preferably, the mixed material in step (4) further includes any one or a combination of at least two of antioxidants, acid absorbers or nucleating agents.

[0065] Preferably, the extrusion process further includes a granulation step.

[0066] Thirdly, the present invention provides a component formed from polypropylene material as described in the first aspect.

[0067] Preferably, the molding process includes injection molding.

[0068] Fourthly, the present invention provides an application of the polypropylene material as described in the first aspect in automobiles or home appliances.

[0069] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0070] Compared with the prior art, the present invention has the following beneficial effects: In the polypropylene material provided by this invention, the homopolymer polypropylene segments of the copolymer polypropylene have extremely high isotacticity, and by controlling the composition of its rubber phase segments and the mass percentage of the rubber phase, a polypropylene material with high melt index, high modulus, and high impact is obtained. Detailed Implementation

[0071] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0072] The sources of some components in the following examples and comparative examples are as follows: (1) Main catalyst The main catalyst-1 was manufactured by Renqiu Lihe Technology Development Co., Ltd. SP-4 had a Dv(0.5) of 51 μm, and its internal electron donor was 9,9-bis(methoxymethyl)fluorene, with a mass percentage of 9.7%. Main catalyst-2, Beijing Aoda Branch of Sinopec Catalyst Co., Ltd., HR-G, Dv(0.5) is 58μm, internal electron donor is 3,3-dimethoxymethyl-2,6-dimethylheptane, and the mass percentage of internal electron donor is 9.6%; The main catalyst-3, manufactured by Yingkou Xiangyang Catalyst Co., Ltd., is CS-2-D with a Dv(0.5) of 50 μm. The internal electron donor is 9,9-bis(methoxymethyl)fluorene, and the mass percentage of the internal electron donor is 8.1%. Catalyst-4, Clariant Chemicals Technology (Shanghai) Co., Ltd., Polymax 610, Dv(0.5) is 52μm, internal electron donor is 3,3-dimethoxymethyl-2,6-dimethylheptane, and the mass percentage of internal electron donor is 9%; The main catalyst-5 was manufactured by Yingkou Xiangyang Catalyst Co., Ltd. CS-2 had a Dv(0.5) of 40 μm, and its internal electron donor was 9,9-bis(methoxymethyl)fluorene with a mass percentage of 7.8%. The main catalyst-6, manufactured by Beijing Aoda Branch of Sinopec Catalyst Co., Ltd., is DQC 401 with a Dv(0.5) of 52 μm. The internal electron donors are diethyl phthalate and diisobutyl phthalate, with a mass percentage content of 8.6%. (2) No. 68 white oil: Beijing Hengpurui Trade Co., Ltd.; (3) Vaseline: Beijing Hengpurui Trade Co., Ltd.; (4) Antioxidant 1010: Sanfeng Chemical Co., Ltd., Linyi City, Shandong Province; (5) Antioxidant 168: Sanfeng Chemical Co., Ltd., Linyi City, Shandong Province; (6) Calcium hexahydrophthalate: Chenghe Technology Co., Ltd.; (7) Calcium stearate: Jiangxi Hongyuan Chemical Co., Ltd.

[0073] Example 1 A polypropylene material, wherein the components of the polypropylene material include copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate and acid scavenger calcium stearate, and the mass ratio of the five components is 2000:1:1:1:1; The preparation method of the polypropylene material includes the following steps: (1) Add the main catalyst-1, white oil and petroleum jelly into the main catalyst tank in a ratio of 80kg:120L:240L, mix them evenly at 70℃ and then cool them down to 10℃ to obtain the main catalyst paste-1. The main catalyst paste-1 and the co-catalyst triethylaluminum were added to a pre-complexing reactor for pre-complexation. The temperature of the pre-complexing reactor was controlled at 10±1℃ and the pre-complexation time was 60min to obtain a pre-complexed catalyst. The molar ratio of Ti to Al in the catalyst was 1:30. The pre-complexed catalyst overflows into the prepolymerization reactor and mixes with propylene to carry out a prepolymerization reaction; the propylene feed rate is 3.5 t / h, the prepolymerization reaction temperature is 15℃, the time is 10 min, the pressure is 3.4 MPa, the prepolymerization reaction ratio is 100 times, and a prepolymerization slurry is obtained. (2) The prepolymerized slurry overflows into the first loop reactor and undergoes polymerization reaction with propylene and hydrogen, and then undergoes polymerization reaction in the second loop reactor connected in series to obtain homopolymer polypropylene; the propylene injection rate is 45t / h; the hydrogen concentration in the first loop reactor is 4000ppm and the hydrogen concentration in the second loop reactor is 5000ppm; the reaction pressure in both the first and second loop reactors is 3.5MPa, the reaction temperature is 67℃, and the total polymerization reaction time is 30min. (3) The homopolymer polypropylene is continuously fed into a vertical gas phase reactor and copolymerized with continuously fed ethylene and propylene for 40 min to obtain copolymer polypropylene; the temperature in the gas phase reactor is 68℃, the pressure is 1.6MPa, the molar ratio of ethylene to propylene in the gas phase reactor is 0.15:1, and the propylene injection rate is 5t / h. (4) The copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate and calcium stearate are mixed evenly to obtain a blend, which is then extruded and granulated to obtain the polypropylene material.

[0074] Example 2 A polypropylene material, wherein the components of the polypropylene material include copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent sodium 2,2'-methylene-di-(4,6-di-tert-butylphenyl)phosphate and acid scavenger hydrotalcite, wherein the mass ratio of the five components is 2000:1:1:2:1; The preparation method of the polypropylene material includes the following steps: (1) Add the main catalyst-2, white oil and petroleum jelly into the main catalyst tank in a ratio of 80kg:120L:240L, mix them evenly at 70℃ and then cool them down to 10℃ to obtain the main catalyst paste-2. The main catalyst paste-2 and the co-catalyst triethylaluminum were added to a pre-complexing reactor for pre-complexation. The temperature of the pre-complexing reactor was controlled at 10±1℃ and the pre-complexation time was 60min to obtain a pre-complexed catalyst. The molar ratio of Ti to Al in the catalyst was 1:27. The pre-complexed catalyst overflows into the prepolymerization reactor and mixes with propylene to carry out a prepolymerization reaction; the propylene feed rate is 3.5 t / h, the prepolymerization reaction temperature is 15℃, the time is 10 min, the pressure is 3.4 MPa, the prepolymerization reaction ratio is 100 times, and a prepolymerization slurry is obtained. (2) The prepolymerized slurry overflows into the first loop reactor and undergoes polymerization reaction with propylene and hydrogen, and then undergoes polymerization reaction in the second loop reactor connected in series to obtain homopolymer polypropylene; the propylene injection rate is 45t / h; the hydrogen concentration in the first loop reactor is 4000ppm and the hydrogen concentration in the second loop reactor is 5000ppm; the reaction pressure in both the first and second loop reactors is 3.5MPa, the reaction temperature is 67℃, and the total polymerization reaction time is 30min. (3) The homopolymer polypropylene is continuously fed into a vertical gas phase reactor and copolymerized with continuously fed ethylene and propylene for 50 min to obtain copolymer polypropylene; the temperature in the gas phase reactor is 68℃, the pressure is 1.6MPa, the molar ratio of ethylene to propylene in the gas phase reactor is 0.1:1, and the propylene injection rate is 5.5t / h. (4) The copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent 2,2'-methylene-di-(4,6-di-tert-butylphenyl)phosphate sodium salt and hydrotalcite are mixed evenly to obtain a blend, which is then extruded and granulated to obtain the polypropylene material.

[0075] Example 3 A polypropylene material, wherein the components of the polypropylene material include copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate, and acid scavenger calcium stearate, wherein the mass ratio of the five components is 2000:1:2:1:1. The preparation method of the polypropylene material includes the following steps: (1) Add the main catalyst-3, white oil and petroleum jelly into the main catalyst tank in a ratio of 80kg:120L:240L, mix them evenly at 70℃ and then cool them down to 10℃ to obtain the main catalyst paste-3. The main catalyst paste-3 and the co-catalyst triethylaluminum were added to a pre-complexing reactor for pre-complexation. The temperature of the pre-complexing reactor was controlled at 10±1℃ and the pre-complexation time was 60min to obtain a pre-complexed catalyst. The molar ratio of Ti to Al in the catalyst was 1:27. The pre-complexed catalyst overflows into the prepolymerization reactor and mixes with propylene to carry out a prepolymerization reaction; the propylene feed rate is 3.5 t / h, the prepolymerization reaction temperature is 15℃, the time is 10 min, the pressure is 3.4 MPa, the prepolymerization reaction ratio is 60 times, and a prepolymerization slurry is obtained. (2) The prepolymerized slurry overflows into the first loop reactor and undergoes polymerization reaction with propylene and hydrogen, and then undergoes polymerization reaction in the second loop reactor connected in series to obtain homopolymer polypropylene; the propylene injection rate is 45t / h; the hydrogen concentration in the first loop reactor is 3000ppm and the hydrogen concentration in the second loop reactor is 4400ppm; the reaction pressure in both the first and second loop reactors is 3.5MPa, the reaction temperature is 67℃, and the total polymerization time is 25min. (3) The homopolymer polypropylene is continuously fed into a vertical gas phase reactor and copolymerized with continuously fed ethylene and propylene for 40 min to obtain copolymer polypropylene; the temperature in the gas phase reactor is 68℃, the pressure is 1.6MPa, the molar ratio of ethylene to propylene in the gas phase reactor is 0.1:1, and the propylene injection rate is 5t / h. (4) The copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate and calcium stearate are mixed evenly to obtain a blend, which is then extruded and granulated to obtain the polypropylene material.

[0076] Example 4 A polypropylene material, wherein the components of the polypropylene material include copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum and acid scavenger calcium stearate, wherein the mass ratio of the five components is 2000:1:2:2:1. The preparation method of the polypropylene material includes the following steps: (1) Add the main catalyst-3, white oil and petroleum jelly into the main catalyst tank in a ratio of 80kg:120L:240L, mix them evenly at 70℃ and then cool them down to 10℃ to obtain the main catalyst paste-3. The main catalyst paste-3 and the co-catalyst triethylaluminum were added to a pre-complexing reactor for pre-complexation. The temperature of the pre-complexing reactor was controlled at 10±1℃ and the pre-complexation time was 60min to obtain a pre-complexed catalyst. The molar ratio of Ti to Al in the catalyst was 1:27. The pre-complexed catalyst overflows into the prepolymerization reactor and mixes with propylene to carry out a prepolymerization reaction; the propylene feed rate is 3.5 t / h, the prepolymerization reaction temperature is 15℃, the time is 10 min, the pressure is 3.4 MPa, the prepolymerization reaction ratio is 60 times, and a prepolymerization slurry is obtained. (2) The prepolymerized slurry overflows into the first loop reactor and undergoes polymerization reaction with propylene and hydrogen, and then undergoes polymerization reaction in the second loop reactor connected in series to obtain homopolymer polypropylene; the propylene injection rate is 45t / h; the hydrogen concentration in the first loop reactor is 4800ppm and the hydrogen concentration in the second loop reactor is 6000ppm; the reaction pressure in both the first and second loop reactors is 3.5MPa, the reaction temperature is 67℃, and the total polymerization time is 30min. (3) The homopolymer polypropylene is continuously fed into a vertical gas phase reactor and copolymerized with continuously fed ethylene and propylene for 40 min to obtain copolymer polypropylene; the temperature in the gas phase reactor is 68℃, the pressure is 1.6MPa, the molar ratio of ethylene to propylene in the gas phase reactor is 0.15:1, and the propylene injection rate is 5t / h. (4) The copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum and calcium stearate are mixed evenly to obtain a blend, which is then extruded and granulated to obtain the polypropylene material.

[0077] Example 5 A polypropylene material, wherein the components of the polypropylene material include copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate and acid scavenger calcium stearate, and the mass ratio of the five components is 2000:1:2:1:1.4. The preparation method of the polypropylene material includes the following steps: (1) Add the main catalyst-4, white oil and petroleum jelly into the main catalyst tank in a ratio of 80kg:120L:240L, mix them evenly at 70℃ and then cool them down to 10℃ to obtain the main catalyst paste-4. The main catalyst paste-4 and the co-catalyst triethylaluminum were added to a pre-complexing reactor for pre-complexation. The temperature of the pre-complexing reactor was controlled at 10±1℃ and the pre-complexation time was 60min to obtain a pre-complexed catalyst. The molar ratio of Ti to Al in the catalyst was 1:27. The pre-complexed catalyst overflows into the prepolymerization reactor and mixes with propylene to carry out a prepolymerization reaction; the propylene feed rate is 3.5 t / h, the prepolymerization reaction temperature is 15℃, the time is 10 min, the pressure is 3.4 MPa, the prepolymerization reaction ratio is 100 times, and a prepolymerization slurry is obtained. (2) The prepolymerized slurry overflows into the first loop reactor and undergoes polymerization reaction with propylene and hydrogen, and then undergoes polymerization reaction in the second loop reactor connected in series to obtain homopolymer polypropylene; the propylene injection rate is 45t / h; the hydrogen concentration in the first loop reactor is 4800ppm and the hydrogen concentration in the second loop reactor is 6000ppm; the reaction pressure in both the first and second loop reactors is 3.5MPa, the reaction temperature is 67℃, and the total polymerization time is 25min; (3) The homopolymer polypropylene is continuously fed into a vertical gas phase reactor and copolymerized with continuously fed ethylene and propylene for 40 min to obtain copolymer polypropylene; the temperature in the gas phase reactor is 68℃, the pressure is 1.6MPa, the molar ratio of ethylene to propylene in the gas phase reactor is 0.15:1, and the propylene injection rate is 5t / h. (4) The copolymer polypropylene, antioxidant 1010, antioxidant 168, nucleating agent calcium hexahydrophthalate and calcium stearate are mixed evenly to obtain a blend, which is then extruded and granulated to obtain the polypropylene material.

[0078] Example 6 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that copolymerization is performed for 30 minutes in step (3). All other raw materials, process parameters and steps are the same as in Example 1.

[0079] Comparative Example 1 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the main catalyst-1 in step (1) is replaced by the same mass as the main catalyst-5. The hydrogen concentration in the first loop reactor is 8000 ppm, and the hydrogen concentration in the second loop reactor is 9000 ppm. The other raw materials, process parameters and steps are the same as in Example 1.

[0080] Comparative Example 2 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the main catalyst-1 in step (1) is replaced by the same mass as the main catalyst-6. The hydrogen concentration in the first loop reactor is 11000ppm and the hydrogen concentration in the second loop reactor is 12000ppm. The other raw materials, process parameters and steps are the same as in Example 1.

[0081] Comparative Example 3 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that in step (1), the main catalyst paste-1, the co-catalyst triethylaluminum, and the external electron donor cyclohexylmethyldimethoxysilane are added to a pre-complexing reactor for pre-complexation. The amounts of the main catalyst paste-1 and the co-catalyst triethylaluminum are the same as in Example 1, and the T / D mass ratio is 20:1 (T is triethylaluminum, and D is the external electron donor). The other raw materials, process parameters, and steps are the same as in Example 1.

[0082] Comparative Example 4 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the molar ratio of ethylene to propylene in step (3) is 0.4:1 and the propylene injection rate is 5t / h. The other raw materials, process parameters and steps are the same as in Example 1.

[0083] Comparative Example 5 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the temperature of the prepolymerization reaction in step (1) is 18°C, the time of the prepolymerization reaction is 15 min, and the multiplication factor of the prepolymerization reaction is 200 times. The other raw materials, process parameters and steps are the same as those in Example 1.

[0084] Comparative Example 6 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the total polymerization time in step (2) is 40 min. The other raw materials, process parameters and steps are the same as in Example 1.

[0085] Comparative Example 7 A polypropylene material and its preparation method are disclosed. The only difference between this material and Example 1 is that the hydrogen concentration in the first loop reactor in step (2) is 5500 ppm. The other raw materials, process parameters and steps are the same as in Example 1.

[0086] The homopolymer polypropylene and polypropylene materials in the examples and comparative examples were tested according to the following methods, and the test results are shown in Table 1. (1) Melt index: Tested according to GB / T 3682.1-2018 (Method B); (2) Isotacticity: Tested according to GB / T2412-2008; (3) Mass percentage of rubber phase and mass percentage of ethylene units in rubber phase: The absorbance of 0.3 mm thin film (melt pressing method) was tested using an FT-IR instrument (Bruker Tensor 27). The characteristic peak of ethylene (755 cm⁻¹) was measured. -1 -705cm -1 The area of ​​the rubber phase was calculated by substituting it into the external standard curve; the rubber phase content was calculated by FTIR method using the ratio of crystalline to amorphous segments in the characteristic peaks of ethylene. (4) Impact strength of cantilever beam: Tested according to GB / T1843-2008; (5) Bending modulus: Tested according to GB / T 9341-2008.

[0087] Table 1 As can be seen from the test data in Table 1, the polypropylene material provided by this invention has the characteristics of high melt index, high modulus and high impact resistance, which can well meet the processing and use requirements of large thin-walled parts.

[0088] A comparison between Example 1 and Example 6 shows that controlling the mass percentage of ethylene units in the rubber phase within a preferred range can effectively adjust the impact strength of polypropylene materials.

[0089] A comparison between Example 1 and Comparative Example 1 shows that selecting a main catalyst with a larger Dv(0.5) ensures sufficient catalytic activity during copolymerization, effectively increasing the rubber phase content of the copolymerized polypropylene and thus giving the polypropylene material better impact strength. Comparative Example 1 used a main catalyst with a smaller Dv(0.5). Due to the reduced Dv(0.5), hydrogen sensitivity decreased. Therefore, the hydrogen concentration in the first and second loop reactors was increased to improve the melt index of the polypropylene material. However, even with the increased hydrogen concentration, a high melt index polypropylene material could not be obtained.

[0090] A comparison of Example 1 and Comparative Example 2 shows that selecting a specific internal electron donor can result in polypropylene materials with higher melt index, impact strength, and flexural modulus. Comparative Example 2 used diethyl phthalate and diisobutyl phthalate as the main catalysts with reduced hydrogen sensitivity. Therefore, the hydrogen concentration in the first and second loop reactors was increased to improve the melt index of the polypropylene material. However, even with the increased hydrogen concentration, a high melt index polypropylene material could not be obtained.

[0091] As can be seen from the comparison between Example 1 and Comparative Example 3, after the introduction of an external electron donor, the isotactic index of the homopolymer polypropylene chain segments in the copolymer polypropylene is too high, and the impact strength of the polypropylene material is actually lower.

[0092] As can be seen from the comparison between Example 1 and Comparative Example 4, the molar ratio of ethylene to propylene is too large, resulting in lower impact strength and flexural modulus of polypropylene material.

[0093] As can be seen from the comparison between Example 1 and Comparative Example 5, the prepolymerization reaction factor is too large, resulting in lower impact strength and flexural modulus of polypropylene material.

[0094] As can be seen from the comparison between Example 1 and Comparative Example 6, the polymerization reaction time is too long, resulting in lower melt index, impact strength and flexural modulus of polypropylene material.

[0095] As can be seen from the comparison between Example 1 and Comparative Example 7, the hydrogen concentration in the first loop reactor is too high, resulting in low impact strength of the polypropylene material.

[0096] The applicant declares that this invention illustrates the polypropylene material, its preparation method, and its application through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A polypropylene material, characterized in that, The components of the polypropylene material include copolymerized polypropylene; The copolymer polypropylene comprises a continuous phase formed of homopolymer polypropylene segments and a rubber phase formed of ethylene-propylene copolymer segments; The isotacticity of the homopolymer polypropylene segments is 98-99%; the mass percentage of the rubber phase in the copolymer polypropylene is 10-15%; and the mass percentage of ethylene units in the rubber phase is 20-40%. The melt flow index of the polypropylene material is 60-100 g / 10 min.

2. The polypropylene material according to claim 1, characterized in that, The mass percentage of ethylene units in the rubber phase is 30-36%; Preferably, the melt flow index of the polypropylene material is 65-100 g / 10 min; Preferably, the polypropylene material has a cantilever beam impact strength >6 kJ / m at 23°C. 2 Further optimization of 7-8.5 kJ / m 2 ; Preferably, the flexural modulus of the polypropylene material is ≥1600MPa, and more preferably 1650-1800MPa.

3. The polypropylene material according to claim 1, characterized in that, The polypropylene material also includes a nucleating agent; Preferably, the nucleating agent comprises any one or a combination of at least two of calcium hexahydrophthalate, aluminum p-tert-butylbenzoate, sodium 2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate or basic aluminum 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate); Preferably, the mass ratio of the copolymerized polypropylene to the nucleating agent is (1000-2000):

1.

4. The polypropylene material according to claim 1, characterized in that, The polypropylene material also includes antioxidants; Preferably, the antioxidant comprises any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tris[2,4-di-tert-butylphenyl]phosphite, or pentaerythritol diphosphite. Preferably, the mass ratio of the copolymer polypropylene to the antioxidant is (500-1000):1; Preferably, the polypropylene material further includes an acid scavenger; Preferably, the acid absorbent comprises calcium stearate and / or hydrotalcite; Preferably, the mass ratio of the copolymer polypropylene to the acid absorbent is (1400-2000):

1.

5. A method for preparing a polypropylene material as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Propylene is mixed with a catalyst and then subjected to a prepolymerization reaction to obtain a prepolymerized slurry; The catalyst comprises a main catalyst and a co-catalyst; the main catalyst is a Ziegler-Natta catalyst; the Ziegler-Natta catalyst has an internally supported electron donor; the internal electron donor comprises any one or a combination of at least two of 9,9-bis(methoxymethyl)fluorene, 9,9-bis(methyl benzoate)fluorene, 3,3-bismethoxymethyl-2,6-dimethylheptane, or cyclobutyl-1,1-diethanol dimethyl ether; the Dv(0.5) of the Ziegler-Natta catalyst is 50-60 μm; the multiplication factor of the prepolymerization reaction is 50-100 times. (2) The prepolymerized slurry, propylene and hydrogen are polymerized in a first loop reactor and a second loop reactor connected in series to obtain homopolymer polypropylene; The hydrogen concentration in the first loop reactor is 3000-5000 ppm; the hydrogen concentration in the second loop reactor is 4000-6000 ppm; and the total polymerization time is 25-35 min. (3) The homopolymer polypropylene, propylene and ethylene are copolymerized to obtain copolymer polypropylene; the molar ratio of ethylene to propylene is (0.1-0.2):1; (4) The copolymer polypropylene is extruded to obtain the polypropylene material.

6. The preparation method according to claim 5, characterized in that, The main catalyst is a heterogeneous spherical Ziegler-Natta catalyst; Preferably, the mass percentage of the internal electron donor in the main catalyst is 5-10%; Preferably, the co-catalyst comprises alkylaluminum; Preferably, the alkylaluminum comprises triethylaluminum; Preferably, the molar ratio of Ti to Al in the catalyst is 1:(5-50). Preferably, the catalyst is pre-complexed before the prepolymerization reaction is carried out; Preferably, the pre-complexation includes the following steps: (S1) Mix the main catalyst, white oil and petrolatum at 65-75°C, and then cool to 9-11°C to obtain the main catalyst paste; (S2) The main catalyst paste is pre-complexed with the co-catalyst to obtain a pre-complexed catalyst; Preferably, the pre-complexation temperature is 9-15°C; Preferably, the pre-complexation time is 30-60 minutes; Preferably, the ratio of the main catalyst, white oil and petrolatum is 1 kg: (1.45-1.55) L: (2.95-3.05) L.

7. The preparation method according to claim 5, characterized in that, The temperature of the prepolymerization reaction is 10-20℃; Preferably, the pressure of the prepolymerization reaction is 3-4 MPa; Preferably, the prepolymerization reaction takes 10-20 minutes; Preferably, the reaction temperatures in the first loop reactor and the second loop reactor are each independently 65-70°C; Preferably, the reaction pressure in the first loop reactor and the second loop reactor is independently 3.2-3.8 MPa; Preferably, the melt index of the homopolymer polypropylene is 100-200 g / 10 min.

8. The preparation method according to claim 5, characterized in that, The copolymerization temperature is 66-70℃; Preferably, the copolymerization time is 30-50 minutes; Preferably, the copolymerization pressure is 1.55-1.65 MPa; Preferably, the copolymerization is carried out in a vertical gas-phase reactor; Preferably, the mixed material in step (4) further includes any one or a combination of at least two of antioxidants, acid absorbers, or nucleating agents; Preferably, the extrusion process further includes a granulation step.

9. A component, characterized in that, The component is formed from the polypropylene material as described in any one of claims 1-4.

10. The application of a polypropylene material as described in any one of claims 1-4 in automobiles or home appliances.

Images