A reinforced and toughened polypropylene sheet and its preparation method

Abstract

This invention discloses a reinforced and toughened polypropylene sheet and its preparation method, relating to the field of polymer materials technology. The reinforced and toughened polypropylene sheet prepared by this invention involves first copolymerizing butene, long-chain olefins, and 2-allylfuran to obtain a toughening elastomer; then reacting the brominated long-chain olefins with tris(4-bromophenyl)amine and carbazole to obtain unsaturated heat stabilizer A and unsaturated heat stabilizer B, respectively; next, copolymerizing propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allylmaleimide to obtain a modified polypropylene resin; finally, mixing the modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant, and extruding to obtain the reinforced and toughened polypropylene sheet. The polypropylene sheet prepared by this invention exhibits superior anti-aging properties, tensile strength, and impact resistance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a reinforced and toughened polypropylene sheet and its preparation method. Background Technology

[0002] Polypropylene (PP), with its excellent processability, chemical stability, and economy, is widely used in packaging, automotive, and construction industries. However, PP is brittle and has low impact strength at low temperatures, limiting its application in scenarios requiring high toughness. PP's high crystallinity makes it prone to brittleness, which, despite its high rigidity, exacerbates the brittleness problem.

[0003] Therefore, introducing elastomers has become a common strategy to improve the toughness of PP, among which polybutene elastomer (PB-E) is highly favored due to its good compatibility with PP. PB-E can form stable microphase separation in PP, constructing a continuous network, effectively dispersing external forces, and improving impact resistance. However, the poor compatibility of PB-E with PP may weaken the tensile strength and impact toughness of the sheet.

[0004] Therefore, the applicant has developed a reinforced and toughened polypropylene sheet to address the aforementioned problems. Summary of the Invention

[0005] To address the existing technical problems, the present invention provides an enhanced and toughened polypropylene sheet, wherein the raw material components, by weight, include: 50 parts by weight of modified polypropylene resin, 13-17 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1-2 parts by weight of antioxidant.

[0006] The modified polypropylene resin is obtained by copolymerization of propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allyl maleimide.

[0007] Furthermore, the toughened elastomer is obtained by copolymerization of butene, long-chain olefins, and 2-allylfuran.

[0008] Furthermore, the unsaturated heat stabilizer A is obtained by reacting a brominated long-chain olefin with tris(4-bromophenyl)amine.

[0009] Furthermore, the unsaturated heat stabilizer B is obtained by reacting a brominated long-chain olefin with carbazole.

[0010] Furthermore, the long-chain olefin has at least 12 carbon atoms.

[0011] Furthermore, the stabilizer is zinc phosphate.

[0012] Furthermore, the lubricant is polyethylene wax.

[0013] Furthermore, the antioxidant is obtained by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2.

[0014] This invention also provides a method for preparing reinforced and toughened polypropylene sheets, the preparation steps of which are as follows:

[0015] Modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant were dried in a vacuum oven at 60℃ for 12–14 hours. Then, 50 parts by weight of modified polypropylene resin, 12–14 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1–2 parts by weight of antioxidant were added to a twin-screw mixer for mixing at 190℃ and a twin-screw speed of 100 r / min for 5 minutes. Afterward, a pressure of 0.5 MPa was applied and maintained for 2 minutes before direct extrusion molding to obtain reinforced and toughened polypropylene sheets.

[0016] Furthermore, the modified polypropylene resin is prepared as follows:

[0017] The high-pressure polymerization reactor was dried, and then the product was mixed under vacuum at a mass ratio of 156–158:

[0018] 2.9~3.1:9.9~10.1:2.6~2.8:0.29~0.31 Toluene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, N-allylmaleimide, and triisobutylaluminum were added sequentially. The mixture was stirred at 300~500 rpm for 4~6 min. After adding dimethylpyridinium imide hafnium complex and [Ph3C][B(C6F5)4], the molar ratio of dimethylpyridinium imide hafnium complex to [Ph3C][B(C6F5)4] was 1:2. The mass of the dimethylpyridineimine hafnium complex was 0.0002 to 0.0004 times the mass of propylene. Propylene gas at a pressure of 5 atm was introduced and stirred at 550 rpm for 9 to 11 minutes at 50°C. The molar ratio of propylene to unsaturated heat stabilizer B was 99:0.35. After depressurization, 200 times the mass of propylene was added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the product. The mixture was filtered, washed three times with ethanol, and then dried to constant weight in a vacuum drying oven at 40°C to obtain modified polypropylene resin.

[0019] Furthermore, the preparation method of the unsaturated heat stabilizer A is as follows:

[0020] Under nitrogen protection, tris(4-bromophenyl)amine and potassium tert-butoxide were mixed at a mass ratio of 26–28:1. Then, anhydrous tetrahydrofuran, at a mass ratio of 9–11 times that of tris(4-bromophenyl)amine, was added and stirred until dissolved. The mixture was stirred continuously in a cryogenic bath at -78°C for 50–70 min. Next, a 1.3 M tert-butyllithium hexane solution, at a mass ratio of 6–8 times that of tris(4-bromophenyl)amine, was added dropwise over 1.9–2.1 h. After stirring for another 30 min, the mixture was heated to 0°C and stirred for another 3 h. Next, 1.1 to 1.3 times the mass of tris(4-bromophenyl)amine and 18-bromo-1-octadecene obtained by vacuum distillation were added, and the mixture was stirred continuously for 11 to 13 hours. Then, the reaction was quenched by adding 50 to 70 times the mass of the saturated ammonium chloride solution. The mixture was then extracted and separated, extracted three times with diethyl ether, and the organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate, then filtered to remove black oily solid impurities. The mixture was then subjected to silica gel column chromatography with n-hexane as the developing solvent, and the unsaturated heat stabilizer A was obtained by vacuum distillation.

[0021] Furthermore, the preparation method of the unsaturated heat stabilizer B is as follows:

[0022] Under nitrogen protection, 9H-carbazole, a mineral oil suspension of 60% sodium hydride, and anhydrous dimethylformamide were mixed at a mass ratio of 9:2.3:15-20 and stirred at 25°C for 50-70 min. Then, 3-5 times the mass of 9H-carbazole after vacuum distillation of 18-bromo-1-octadecene was added dropwise at 2-4 s / drop. The mixture was heated to 80°C and stirred under reflux for 1.9-2.1 h. The reaction was then quenched by adding 50-70 times the mass of saturated ammonium chloride solution. After extraction and separation, the organic phases were extracted three times with dichloromethane, and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate and subjected to column chromatography with n-hexane as the eluent. Finally, the unsaturated heat stabilizer B was obtained by vacuum distillation.

[0023] Furthermore, the method for preparing the toughened elastomer is as follows:

[0024] The high-pressure polymerization reactor was dried, and then toluene, 1-eicosene, and 2-allylfuran were added sequentially under vacuum in a mass ratio of 52-54:24-28:30-40. The temperature was raised to 40°C, and butene gas at a pressure of 0.1 MPa was introduced. The mass ratio of butene to 1-eicosene was 32-46:24-28. Triisobutylaluminum, [Ph3C][B(C6F5)4], and dimethylpyridineimine hafnium complex were added sequentially in a molar ratio of 100:2:1. The mass of triisobutylaluminum was 0.0002-0.0004 times that of butene. The mixture was stirred at 550 rpm for 9-11 min, and then the pressure was released. The mixture was precipitated in an ethanol solution of 2% hydrochloric acid (200 times the mass of propylene by volume), filtered, and dried in a vacuum oven to constant weight to obtain the toughened elastomer.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The reinforced and toughened polypropylene sheet prepared by this invention is obtained by first copolymerizing butene, long-chain olefins, and 2-allylfuran to obtain a toughening elastomer; reacting the brominated long-chain olefins with tris(4-bromophenyl)amine and carbazole respectively to obtain unsaturated heat stabilizer A and unsaturated heat stabilizer B; then copolymerizing propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allylmaleimide to obtain a modified polypropylene resin; finally, the modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant are mixed and extruded to obtain the reinforced and toughened polypropylene sheet. The polypropylene sheet prepared by this invention exhibits improved anti-aging properties, tensile strength, and impact resistance.

[0027] This invention introduces furan into toughened elastomers. The introduction of 2-allyl furan units alters the original structure of a single polybutene chain, forming a copolymer chain containing alternating or randomly distributed butene and furan units. The furan ring has high polarity and reactivity, which can promote the formation of stronger hydrogen bonds or other secondary interactions between molecules, thereby improving the cohesiveness and thermal stability of the toughened elastomer material. The presence of the furan ring increases the chemical resistance of the toughened elastomer material. Due to the special structure of the furan ring, the modified polybutene elastomer is more resistant to acids, alkalis, solvents, and other corrosive chemicals.

[0028] The toughened elastomer of the present invention is obtained by copolymerization of long-chain olefins. By increasing the molecular weight, making the molecular weight distribution more uniform, reducing the crystallinity, and increasing the intermolecular interaction, the impact strength and toughness of the toughened elastomer are improved. Subsequently, when mixed with modified polypropylene resin, its flexibility is enhanced, but the tensile strength of the modified polypropylene resin is weakened.

[0029] This invention copolymerizes propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allylmaleimide to obtain a modified polypropylene resin. On one hand, unsaturated heat stabilizer A and unsaturated heat stabilizer B introduce rigid groups with large conjugated structures, namely triphenylamine and carbazole groups, into the modified polypropylene resin. Triphenylamine and carbazole groups themselves possess excellent thermal and light stability properties; introducing them into the polypropylene chain can improve the thermal and light stability of the polypropylene. On the other hand, the tris(4-bromophenyl)amine of unsaturated heat stabilizer A reacts with a brominated long-chain olefin to graft the long-chain olefin onto the triphenylamine, followed by grafting... Triphenylamine, containing long-chain olefins, is copolymerized with propylene, unsaturated heat stabilizer B, and N-allyl maleimide via unsaturated bonds to obtain a modified polypropylene resin with a hyperbranched structure. Maleimide groups are uniformly distributed in the cavities of the modified polypropylene resin. When preparing reinforced and toughened polypropylene sheets, the toughening elastomer penetrates the cavity and crosslinks with the modified polypropylene resin. At the same time, the furan groups on the surface of the toughening elastomer undergo a Diels-Alder reaction with the maleimide groups on the surface of the cavity, further increasing the degree of crosslinking of the polypropylene sheet. This enhances the flexibility of the polypropylene sheet while improving its tensile strength. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments, but the following embodiments should not be construed as limiting the present invention.

[0031] The following are some of the raw materials used in the embodiments and comparative examples of this invention:

[0032] The hafnium dimethylpyridinium complex was synthesized according to the method reported in the literature [Cai, ZG; Shigemasa, M.; Nakayama, Y.; Shiono, T. Catalytic synthesis of monodisperse polypropylene using a living polymerization system with ansa-fluorenylamidodimethyltitanium-based catalyst. Macromolecules, 2006, 39(19), 6321–6323.].

[0033] The stabilizer used is zinc phosphate.

[0034] The lubricant used is polyethylene wax.

[0035] The antioxidant is obtained by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2.

[0036] Example 1

[0037] A method for preparing reinforced and toughened polypropylene sheets, comprising the following steps:

[0038] Modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant were dried in a vacuum oven at 60℃ for 12 hours. Then, 50 parts by weight of modified polypropylene resin, 12 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1 part by weight of antioxidant were added to a twin-screw mixer for mixing at 190℃ and a twin-screw speed of 100 r / min for 5 minutes. Afterward, a pressure of 0.5 MPa was applied and maintained for 2 minutes before direct extrusion molding to obtain reinforced and toughened polypropylene sheets.

[0039] The modified polypropylene resin is prepared as follows: The high-pressure polymerization reactor is dried, and then under vacuum conditions, toluene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, N-allylmaleimide, and triisobutylaluminum are added sequentially in a mass ratio of 156:2.9:9.9:2.6:0.29. The mixture is stirred at 300 rpm for 4 minutes. Then, dimethylpyridinium imide hafnium complex and [Ph3C][B(C6F5)4] are added. The molar ratio of [4] is 1:2, wherein the mass of the dimethylpyridinium imine hafnium complex is 0.0002 times the mass of propylene. Propylene gas at a pressure of 5 atm is introduced and stirred at 550 rpm for 9 min at 50 °C. The molar ratio of propylene to unsaturated heat stabilizer B is 99:0.35. After depressurization, 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate. The mixture is filtered, washed three times with ethanol, and then dried to constant weight in a vacuum drying oven at 40 °C to obtain modified polypropylene resin.

[0040] The preparation method of the unsaturated heat stabilizer A is as follows: Under nitrogen protection, tris(4-bromophenyl)amine and potassium tert-butoxide are mixed at a mass ratio of 26:1. Then, anhydrous tetrahydrofuran, with a mass of 9 times that of tris(4-bromophenyl)amine, is added and stirred until dissolved. The mixture is stirred continuously in a cryogenic bath at -78°C for 50 min. Then, a 1.3M tert-butyllithium hexane solution is added dropwise over 1.9 h. The mass of the tert-butyllithium hexane solution is 6 times that of tris(4-bromophenyl)amine. After stirring for another 30 min, the temperature is raised to 0°C and the mixture is stirred continuously. The reaction was stirred for 3 hours, followed by the addition of 1.1 times the mass of tris(4-bromophenyl)amine and 18-bromo-1-octadecene obtained by vacuum distillation. The mixture was stirred for 11 hours, and then the reaction was quenched by adding 50 times the mass of saturated ammonium chloride solution. The mixture was then extracted and separated, extracted three times with diethyl ether, and the organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate and then filtered to remove black oily solid impurities. The mixture was then subjected to silica gel column chromatography with n-hexane as the developing solvent and obtained unsaturated heat stabilizer A by vacuum distillation.

[0041] The preparation method of the unsaturated heat stabilizer B is as follows: Under nitrogen protection, 9H-carbazole, a mineral oil suspension of 60% sodium hydride, and anhydrous dimethylformamide were stirred at 25°C for 50 min. Then, 18-bromo-1-octadecene distilled under vacuum was added dropwise at 2 s / drop. The mixture was heated to 80°C and stirred under reflux for 1.9 h. The reaction was then quenched by adding 50 times the mass of saturated ammonium chloride solution. After extraction and separation, the organic phases were combined and the solvent was removed by rotary evaporation after extraction with dichloromethane three times. The mixture was dried overnight with anhydrous magnesium sulfate and subjected to column chromatography with n-hexane as the eluent. Finally, the unsaturated heat stabilizer B was obtained by vacuum distillation.

[0042] The preparation method of the toughened elastomer is as follows: The high-pressure polymerization reactor is dried, and then toluene, 1-eicosene, and 2-allylfuran are added sequentially under vacuum in a mass ratio of 52:28:30. The temperature is raised to 40°C, and butene gas with a pressure of 0.1 MPa is introduced. The mass ratio of butene to 1-eicosene is 32:24. Triisobutylaluminum, [Ph3C][B(C6F5)4], and dimethylpyridineimine hafnium complex are added sequentially in a molar ratio of 100:2:1. The mass of triisobutylaluminum is 0.0002 times that of butene. After stirring at 550 rpm for 9 min, the pressure is released, and 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the elastomer. The solution is filtered, dried in a vacuum oven to constant weight, and the toughened elastomer is obtained.

[0043] Example 2

[0044] A method for preparing reinforced and toughened polypropylene sheets, comprising the following steps:

[0045] Modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant were dried in a vacuum oven at 60℃ for 13 hours. Then, 50 parts by weight of modified polypropylene resin, 13 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1.5 parts by weight of antioxidant were added to a twin-screw mixer for mixing at 190℃ and a twin-screw speed of 100 r / min for 5 minutes. Afterward, a pressure of 0.5 MPa was applied and maintained for 2 minutes before direct extrusion molding to obtain reinforced and toughened polypropylene sheets.

[0046] The modified polypropylene resin is prepared as follows: The high-pressure polymerization reactor is dried, and then under vacuum conditions, toluene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, N-allylmaleimide, and triisobutylaluminum are added sequentially in a mass ratio of 157:3:10:2.7:0.3. The mixture is stirred at 400 rpm for 5 minutes. Then, dimethylpyridinium imide hafnium complex and [Ph3C][B(C6F5)4] are added. The molar ratio of the substances is 1:2, wherein the mass of the dimethylpyridinium imine hafnium complex is 0.0003 times the mass of propylene. Propylene gas at a pressure of 5 atm is introduced and stirred at 550 rpm for 10 min at 50 °C. The molar ratio of propylene to unsaturated heat stabilizer B is 99:0.35. After depressurization, 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the product. The product is filtered, washed three times with ethanol, and then dried to constant weight in a vacuum drying oven at 40 °C to obtain modified polypropylene resin.

[0047] The preparation method of the unsaturated heat stabilizer A is as follows: Under nitrogen protection, tris(4-bromophenyl)amine and potassium tert-butoxide are mixed at a mass ratio of 27:1. Then, anhydrous tetrahydrofuran with a mass of 10 times that of tris(4-bromophenyl)amine is added and stirred until dissolved. The mixture is stirred continuously in a cryogenic bath at -78°C for 60 min. Then, a 1.3M tert-butyllithium hexane solution is added dropwise over 2 h. The mass of the tert-butyllithium hexane solution is 7 times that of tris(4-bromophenyl)amine. After stirring for another 30 min, the temperature is raised to 0°C and the mixture is stirred continuously. The reaction was stirred for 3 hours, followed by the addition of 1.2 times the mass of tris(4-bromophenyl)amine and 18-bromo-1-octadecene obtained by vacuum distillation. The mixture was stirred for 12 hours, and then the reaction was quenched by adding 60 times the mass of saturated ammonium chloride solution. The mixture was then extracted and separated, extracted three times with diethyl ether, and the organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate and then filtered to remove black oily solid impurities. The mixture was then subjected to silica gel column chromatography with n-hexane as the developing solvent and obtained unsaturated heat stabilizer A by vacuum distillation.

[0048] The preparation method of the unsaturated heat stabilizer B is as follows: Under nitrogen protection, 9H-carbazole, a mineral oil suspension of 60% sodium hydride, and anhydrous dimethylformamide are mixed at a mass ratio of 9:2.3:18 and stirred at 25°C for 60 min. Then, 18-bromo-1-octadecene distilled under vacuum is added dropwise at 3 s / drop. The mixture is heated to 80°C and stirred under reflux for 2 h. The reaction is then quenched by adding 60 times the mass of saturated ammonium chloride solution. After extraction and separation, the organic phases are combined and the solvent is removed by rotary evaporation after extraction with dichloromethane three times. The mixture is dried overnight with anhydrous magnesium sulfate and subjected to column chromatography with n-hexane as the eluent. Finally, the unsaturated heat stabilizer B is obtained by vacuum distillation.

[0049] The preparation method of the toughened elastomer is as follows: The high-pressure polymerization reactor is dried, and then toluene, 1-eicosene, and 2-allylfuran are added sequentially under vacuum in a mass ratio of 53:26:35. The temperature is raised to 40°C, and butene gas with a pressure of 0.1 MPa is introduced. The mass ratio of butene to 1-eicosene is 39:26. Triisobutylaluminum, [Ph3C][B(C6F5)4], and dimethylpyridinium imine hafnium complex are added sequentially in a molar ratio of 100:2:1. The mass of triisobutylaluminum is 0.0003 times that of butene. After stirring at 550 rpm for 10 min, the pressure is released, and 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the elastomer. The solution is filtered, dried in a vacuum oven to constant weight, and the toughened elastomer is obtained.

[0050] Example 3

[0051] A method for preparing reinforced and toughened polypropylene sheets, comprising the following steps:

[0052] Modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant were dried in a vacuum oven at 60℃ for 14 hours. Then, 50 parts by weight of modified polypropylene resin, 14 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 2 parts by weight of antioxidant were added to a twin-screw mixer for mixing at 190℃ and a twin-screw speed of 100 r / min for 5 minutes. Afterward, a pressure of 0.5 MPa was applied and maintained for 2 minutes before direct extrusion molding to obtain reinforced and toughened polypropylene sheets.

[0053] The modified polypropylene resin is prepared as follows: The high-pressure polymerization reactor is dried, and then under vacuum conditions, toluene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, N-allylmaleimide, and triisobutylaluminum are added sequentially in a mass ratio of 158:3.1:10.1:2.8:0.31. The mixture is stirred at 500 rpm for 6 minutes. Then, dimethylpyridinium imide hafnium complex and [Ph3C][B(C6F5)4] are added. The molar ratio of the substances in [4] is 1:2, wherein the mass of the dimethylpyridinium imine hafnium complex is 0.0004 times the mass of propylene. Propylene gas at a pressure of 5 atm is introduced and stirred at 550 rpm for 11 min at 50 °C. The molar ratio of propylene to unsaturated heat stabilizer B is 99:0.35. After depressurization, 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the product. The product is filtered, washed three times with ethanol, and then dried to constant weight in a vacuum drying oven at 40 °C to obtain modified polypropylene resin.

[0054] The preparation method of the unsaturated heat stabilizer A is as follows: Under nitrogen protection, tris(4-bromophenyl)amine and potassium tert-butoxide are mixed at a mass ratio of 28:1. Then, anhydrous tetrahydrofuran with a mass of 11 times that of tris(4-bromophenyl)amine is added and stirred until dissolved. The mixture is stirred continuously in a cryogenic bath at -78°C for 70 min. Then, a 1.3M tert-butyllithium hexane solution is added dropwise over 2.1 h. The mass of the tert-butyllithium hexane solution is 8 times that of tris(4-bromophenyl)amine. After stirring for another 30 min, the temperature is raised to 0°C. The reaction was stirred for another 3 hours. Then, 1.3 times the mass of tris(4-bromophenyl)amine and 18-bromo-1-octadecene distilled under vacuum were added. The mixture was stirred for another 13 hours. The reaction was then quenched by adding 70 times the mass of tris(4-bromophenyl)amine to a saturated ammonium chloride solution. The mixture was then extracted and separated into liquid and liquid phases. The liquid was extracted three times with diethyl ether. The organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate and then filtered to remove black oily solid impurities. The mixture was then subjected to silica gel column chromatography with n-hexane as the developing solvent and distilled under vacuum to obtain unsaturated heat stabilizer A.

[0055] The preparation method of the unsaturated heat stabilizer B is as follows: Under nitrogen protection, 9H-carbazole, a mineral oil suspension of 60% sodium hydride, and anhydrous dimethylformamide were stirred at 25°C for 70 min at a mass ratio of 9:2.3:20. Then, 18-bromo-1-octadecene distilled under vacuum was added dropwise at 4 s / drop, and the mixture was heated to 80°C and stirred under reflux for 2.1 h. After quenching the reaction, it was added to a saturated ammonium chloride solution at 70 times its mass. The mixture was then extracted and separated, extracted three times with dichloromethane, and the organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate, and column chromatography was performed using n-hexane as the eluent. Finally, the unsaturated heat stabilizer B was obtained by vacuum distillation.

[0056] The preparation method of the toughened elastomer is as follows: The high-pressure polymerization reactor is dried, and then toluene, 1-eicosene, and 2-allylfuran are added sequentially under vacuum in a mass ratio of 54:24:40. The temperature is raised to 40°C, and butene gas with a pressure of 0.1 MPa is introduced. The mass ratio of butene to 1-eicosene is 46:28. Triisobutylaluminum, [Ph3C][B(C6F5)4], and dimethylpyridineimine hafnium complex are added sequentially in a molar ratio of 100:2:1. The mass of triisobutylaluminum is 0.0004 times that of butene. After stirring at 550 rpm for 11 min, the pressure is released, and 200 times the mass of propylene is added to an ethanol solution of hydrochloric acid with a volume content of 2% to precipitate the product. The product is filtered, dried in a vacuum oven to constant weight, and the toughened elastomer is obtained.

[0057] Comparative Example 1

[0058] The difference between Comparative Example 1 and Example 2 is that only butene and 2-allylfuran are copolymerized to obtain the toughened elastomer; the remaining steps and components are the same as in Example 2.

[0059] Comparative Example 2

[0060] The only difference between Comparative Example 2 and Example 2 is that only butene and long-chain olefins are copolymerized to obtain the toughened elastomer; the remaining steps and components are the same as in Example 2.

[0061] Comparative Example 3

[0062] The only difference between Comparative Example 3 and Example 2 is that butene is copolymerized to obtain a toughened elastomer; the remaining steps and components are the same as in Example 2.

[0063] Comparative Example 4

[0064] The only difference between Comparative Example 4 and Example 2 is that the modified polypropylene resin is obtained by copolymerizing propylene, unsaturated heat stabilizer B, and N-allyl maleimide; the remaining steps and components are the same as in Example 2.

[0065] Comparative Example 5

[0066] The only difference between Comparative Example 5 and Example 2 is that propylene, unsaturated heat stabilizer A, and N-allyl maleimide are copolymerized to obtain modified polypropylene resin; the remaining steps and components are the same as in Example 2.

[0067] Comparative Example 6

[0068] The only difference between Comparative Example 6 and Example 2 is that propylene, unsaturated heat stabilizer A, and unsaturated heat stabilizer B are copolymerized to obtain modified polypropylene resin; the remaining steps and components are the same as in Example 2.

[0069] Example of effect

[0070] Thermo-oxidative aging performance: Reinforced and toughened polypropylene sheets of the same mass as those in the examples and comparative examples were subjected to accelerated thermo-oxidative aging treatment in an electric heating drying oven DHG-9070A. The aging temperature was selected as 90℃ based on the melting point of the samples, the heating method was continuous heating, and the aging time for the samples was 168h.

[0071] The change rate of tensile strength of the reinforced and toughened polypropylene sheet before and after aging was tested. The change rate of tensile strength = 100% * (tensile strength before aging - tensile strength after aging) / tensile strength before aging.

[0072] UV aging performance: Reinforced and toughened polypropylene sheets prepared in the same mass as the examples and comparative examples were subjected to UV aging in the AtlasUVTest UV aging test chamber. The aging process was divided into a light stage and a dark stage. The light stage lasted for 8 hours and the dark stage lasted for 4 hours. The two stages were repeated to simulate the natural aging process of the samples. The conditions for the light stage were: UV wavelength: 300-340nm; temperature: 60±3℃; irradiation intensity: 0.89kW / m2, dry; the conditions for the dark stage were: no UV irradiation; temperature: 50±3℃, condensation. The aging time for the samples was 168 hours.

[0073] The change rate of tensile strength of the reinforced and toughened polypropylene sheet before and after aging was tested. The change rate of tensile strength = 100% * (tensile strength before aging - tensile strength after aging) / tensile strength before aging.

[0074] Tensile strength and elongation at break: Reinforced and toughened polypropylene sheets of the same mass as those in the examples and comparative examples were tested using an INSTRON 3367, USA universal testing machine at 25°C according to ISO 527-1 standard, with a tensile rate of 20 mm / min. At least 5 specimens were tested for each material group to determine its average tensile strength and elongation at break.

[0075] Impact strength: The impact strength of the reinforced and toughened polypropylene sheets prepared by the same mass examples and comparative examples was tested in accordance with GB / T2546.2.

[0076] Table 1 below shows the test and analysis results of various properties of the reinforced and toughened polypropylene sheets prepared using Examples 1-3 and Comparative Examples 1-6 of the present invention.

[0077] Table 1

[0078]

[0079] Table 1 shows that the reinforced and toughened polypropylene sheets prepared in the examples have good tensile strength, toughness, impact strength, and anti-aging properties. Compared with Comparative Examples 1-3, Example 2 shows that the reinforced and toughened polypropylene sheets prepared by copolymerizing butene, long-chain olefins, and 2-allylfuran to obtain a toughened elastomer have good tensile strength, toughness, impact strength, and resistance to thermo-oxidative aging. Compared with Comparative Examples 4-6, Example 2 shows that the reinforced and toughened polypropylene sheets prepared by copolymerizing propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allylmaleimide to obtain a modified polypropylene resin have good tensile strength, toughness, impact strength, resistance to thermo-oxidative aging, and resistance to ultraviolet aging.

[0080] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A reinforced and toughened polypropylene sheet, characterized in that, By weight, the raw material components include: 50 parts by weight of modified polypropylene resin, 12-14 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1-2 parts by weight of antioxidant; the modified polypropylene resin is obtained by copolymerization of propylene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, and N-allylmaleimide; the toughening elastomer is obtained by copolymerization of butene, long-chain olefin, and 2-allylfuran. The unsaturated heat stabilizer A is prepared as follows: Under nitrogen protection, tris(4-bromophenyl)amine and potassium tert-butoxide are mixed at a mass ratio of 26-28:

1. Then, anhydrous tetrahydrofuran, with a mass ratio of 9-11 times that of tris(4-bromophenyl)amine, is added and stirred until dissolved. The mixture is then stirred continuously in a cryogenic bath at -78°C for 50-70 minutes. Next, a 1.3M tert-butyllithium hexane solution is added dropwise over 1.9-2.1 hours. The mass of the tert-butyllithium hexane solution is 6-8 times that of tris(4-bromophenyl)amine. After stirring for another 30 minutes, the temperature is raised to 0°C. The reaction was stirred for another 3 hours. Then, 1.1 to 1.3 times the mass of tris(4-bromophenyl)amine and 18-bromo-1-octadecene distilled under vacuum were added. The mixture was stirred for 11 to 13 hours. The reaction was then quenched by adding 50 to 70 times the mass of tris(4-bromophenyl)amine to a saturated ammonium chloride solution. The mixture was then extracted and separated into liquid and liquid phases. The liquid was extracted three times with diethyl ether. The organic phases were combined and the solvent was removed by rotary evaporation. The mixture was dried overnight with anhydrous magnesium sulfate and then filtered to remove black oily solid impurities. The mixture was then subjected to silica gel column chromatography with n-hexane as the eluent and distilled under vacuum to obtain unsaturated heat stabilizer A. The preparation method of the unsaturated heat stabilizer B is as follows: Under nitrogen protection, 9H-carbazole, a mineral oil suspension of 60% sodium hydride, and anhydrous dimethylformamide are mixed at a mass ratio of 9:2.3:15~20 and stirred at 25°C for 50~70 min. Then, 3~5 times the mass of 9H-carbazole after vacuum distillation of 18-bromo-1-octadecene is added dropwise at 2~4 s / drop. The mixture is heated to 80°C and stirred under reflux for 1.9~2.1 h. The reaction is then quenched by adding 50~70 times the mass of saturated ammonium chloride solution. After extraction and separation, the mixture is extracted three times with dichloromethane, the organic phases are combined and the solvent is removed by rotary evaporation. The mixture is dried overnight with anhydrous magnesium sulfate and subjected to column chromatography with n-hexane as the eluent. Finally, the unsaturated heat stabilizer B is obtained by vacuum distillation. The long-chain olefin has at least 12 carbon atoms.

2. A method for preparing reinforced and toughened polypropylene sheet as described in claim 1, characterized in that, The preparation steps include the following: Modified polypropylene resin, toughening elastomer, stabilizer, lubricant, and antioxidant were dried in a vacuum oven at 60℃ for 12-14 hours. Then, 50 parts by weight of modified polypropylene resin, 12-14 parts by weight of toughening elastomer, 8 parts by weight of stabilizer, 5 parts by weight of lubricant, and 1-2 parts by weight of antioxidant were added to a twin-screw mixer for mixing at a temperature of 190℃ and a twin-screw speed of 100 r / min for 5 minutes. After that, the mixture was directly extruded after being pressurized at 0.5 MPa for 2 minutes to obtain reinforced and toughened polypropylene sheets.

3. The method for preparing reinforced and toughened polypropylene sheets according to claim 2, characterized in that, The modified polypropylene resin is prepared as follows: The high-pressure polymerization reactor was dried. Then, under vacuum conditions, toluene, unsaturated heat stabilizer A, unsaturated heat stabilizer B, N-allylmaleimide, and triisobutylaluminum were added sequentially in a mass ratio of 156~158:2.9~3.1:9.9~10.1:2.6~2.8:0.29~0.

31. The mixture was stirred at 300~500 rpm for 4~6 min. After adding dimethylpyridinium imide hafnium complex and [Ph3C][B(C6F5)4], the molar ratio of dimethylpyridinium imide hafnium complex to [Ph3C][B(C6F5)4] was 1:

2. The mass of dimethylpyridinium imide hafnium complex was 0.0002~0.0004 times the mass of propylene. Propylene gas at a pressure of 5 atm was introduced and the mixture was stirred at 550 rpm at 50°C for 9~11 minutes. The molar ratio of propylene to unsaturated heat stabilizer B was 99:0.

35. After depressurization, the propylene was precipitated in an ethanol solution containing 2% hydrochloric acid (200 times the mass of propylene). The precipitate was filtered, washed three times with ethanol, and then dried to constant weight in a vacuum drying oven at 40°C to obtain modified polypropylene resin.

4. The method for preparing reinforced and toughened polypropylene sheets according to claim 2, characterized in that, The method for preparing the toughened elastomer is as follows: The high-pressure polymerization reactor was dried, and then toluene, 1-eicosene, and 2-allylfuran were added sequentially under vacuum in a mass ratio of 52-54:24-28:30-40. The temperature was raised to 40 °C, and butene gas at a pressure of 0.1 MPa was introduced. The mass ratio of butene to 1-eicosene was 32-46:24-28. Triisobutylaluminum, [Ph3C][B(C6F5)4], and dimethylpyridineimine hafnium complex were added sequentially in a molar ratio of 100:2:

1. The mass of triisobutylaluminum was 0.0002-0.0004 times that of butene. The mixture was stirred at 550 rpm for 9-11 min, and then the pressure was released. The mixture was precipitated in an ethanol solution of hydrochloric acid with a volume content of 2% (200 times the mass of butene), filtered, and dried in a vacuum oven to constant weight to obtain the toughened elastomer.

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