Surface-modified basic magnesium sulphate whiskers and polypropylene alloy materials and methods for their production and bumpers

Abstract

The application relates to the field of exterior parts for new energy vehicles, and discloses surface-modified basic magnesium sulfate whiskers and a polypropylene alloy material, a preparation method of the surface-modified basic magnesium sulfate whiskers and the polypropylene alloy material, and a bumper. The surface-modified basic magnesium sulfate whiskers are obtained by surface modification of basic magnesium sulfate whiskers with a modifier, and the modifier is one or more of methacryloxypropyltrimethoxysilane, lauric acid and dodecyl monophosphate. The polypropylene alloy material is applied to the bumper, and can simultaneously have excellent high rigidity, high impact resistance and high light transmittance.

Description

Technical Field

[0001] This invention relates to the field of exterior parts for new energy vehicles, specifically to a surface-modified basic magnesium sulfate whisker and polypropylene alloy material, their preparation method, and a bumper. Background Technology

[0002] With the increasing penetration of the "plastics replacing steel" trend in the automotive field, automotive parts are gradually being replaced by plastic products. Polypropylene, due to its low density and low cost, has gradually become the dominant material in automotive plastic products during the lightweighting process and is widely used in interior and exterior automotive materials. In recent years, the continuous development of new energy vehicles has introduced many technological and fashionable design elements compared to traditional fuel vehicles, thus requiring some exterior products to have a certain degree of light transmittance while still meeting the original product's mechanical performance requirements.

[0003] CN 117700889 A discloses a high-impact, low-shrinkage transparent PP, its preparation method and application. The preparation method involves melt mixing polypropylene, nucleating agent, transparent inorganic filler, rubber, glass fiber, compatibilizer and additives to obtain high-impact, low-shrinkage transparent PP. However, the light transmittance of this high-impact, low-shrinkage transparent PP is not high.

[0004] CN 114605741 A discloses a polypropylene composite material and its preparation method and application. The polypropylene composite material includes: 65-75 parts of polypropylene, 15-25 parts of toughening agent, 3-8 parts of filler, 0.1-0.2 parts of toughening agent, 3-5 parts of light diffusing agent, 0.1-0.5 parts of antioxidant, and 0.1-0.5 parts of light stabilizer. However, the impact resistance of this polypropylene composite material is poor, and it is difficult to achieve an effective balance between impact resistance and light transmittance.

[0005] CN 117844103 A discloses a polypropylene composite material and its preparation method. The polypropylene composite material includes 30-90 parts of polypropylene resin, 5-30 parts of propylene elastomer, 1-10 parts of maleic anhydride grafted toughening agent, 1-3 parts of dispersant, and 0.5-5 parts of heat stabilizer. Since its application is not a light-transmitting bumper, the product's flexural modulus is only up to 1400 MPa. At the same time, since no filler mineral powder is added, the shrinkage rate cannot be guaranteed.

[0006] Bumpers are critical components in automobiles that withstand impacts, requiring high levels of fluidity, rigidity, and impact resistance. However, traditional bumpers have poor light transmittance, failing to meet customers' demands for a technologically advanced and stylish look. Therefore, the light transmittance design of bumper materials must consider its impact on mechanical properties. Traditional transparent polypropylene has poor mechanical properties, and whether adding mineral powder for stiffening or traditional toughening agents for toughening, it significantly affects the material's light transmittance, failing to meet application requirements.

[0007] Therefore, for the successful application of light-transmitting bumpers, the material must simultaneously possess suitable melt flow index, high rigidity, high impact resistance, and high light transmittance. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing bumper polypropylene alloy materials, which cannot simultaneously guarantee mechanical properties and light transmittance. This invention provides a surface-modified basic magnesium sulfate whisker and polypropylene alloy material, a preparation method thereof, and a bumper. When applied to a bumper, this polypropylene alloy material can simultaneously possess excellent characteristics of high rigidity, high impact resistance, and high light transmittance.

[0009] To achieve the above objectives, the first aspect of the present invention provides a surface-modified basic magnesium sulfate whisker, wherein the surface-modified basic magnesium sulfate whisker is obtained by surface modification of basic magnesium sulfate whisker with a modifier, wherein the modifier is one or more of methacryloyloxypropyltrimethoxysilane, lauric acid and dodecyl monophosphate.

[0010] A second aspect of the present invention provides a polypropylene alloy material, wherein a 3mm square plate of the polypropylene alloy material has a light transmittance of 54-66%, a haze of 89-99.6%, and a notched impact strength of 21-41 kJ / m². 2 The flexural modulus is 1500-1710 MPa; and the raw materials for preparing the polypropylene alloy material include polypropylene, toughening agent, POE compatibilizer and surface-modified basic magnesium sulfate whiskers, wherein the surface-modified basic magnesium sulfate whiskers are the aforementioned surface-modified basic magnesium sulfate whiskers.

[0011] A third aspect of the present invention provides a method for preparing the aforementioned polypropylene alloy material, wherein the method comprises:

[0012] (1) Mix polypropylene, toughening agent and POE compatibilizer to obtain premix;

[0013] (2) The premixed material and surface-modified basic magnesium sulfate whiskers are contacted in a twin-screw extruder for melting, extrusion and granulation to obtain polypropylene alloy material;

[0014] Wherein, the surface-modified basic magnesium sulfate whiskers are the aforementioned surface-modified basic magnesium sulfate whiskers;

[0015] The process conditions of the twin-screw extruder include: zone 1 feed temperature of 150-170℃, zone 2 pressure build-up temperature of 190-200℃, zone 3 pressure build-up temperature of 200-210℃, zone 4 melt temperature of 210-220℃, zone 5 exhaust temperature of 210-220℃, zone 6 conveying temperature of 210-220℃, zone 7 conveying temperature of 210-220℃, zone 8 pressure build-up temperature of 210-220℃, zone 9 pressure build-up temperature of 210-220℃, zone 10 pressure build-up temperature of 210-220℃, zone 11 devolatilization temperature of 210-220℃, zone 12 pressure build-up temperature of 210-220℃, die temperature of 200-210℃, and die head temperature of 190-200℃; the screw speed is 200-300 rpm.

[0016] A fourth aspect of the present invention provides a polypropylene alloy material prepared by the method described above.

[0017] A fifth aspect of the present invention provides a bumper, wherein the bumper comprises the aforementioned polypropylene alloy material.

[0018] Through the above technical solution, the polypropylene alloy material prepared by the present invention, when applied to bumpers, can simultaneously possess excellent characteristics of high rigidity, high impact resistance, and high light transmittance. Preferably, it also has a suitable melt flow index. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] As mentioned above, the first aspect of the present invention provides a surface-modified basic magnesium sulfate whisker, wherein the surface-modified basic magnesium sulfate whisker is obtained by surface modification of basic magnesium sulfate whisker with a modifier, wherein the modifier is one or more of methacryloyloxypropyltrimethoxysilane, lauric acid and dodecyl monophosphate.

[0021] According to the present invention, in a preferred embodiment, the modifier is methacryloyloxypropyltrimethoxysilane.

[0022] According to the present invention, based on the total weight of the surface-modified basic magnesium sulfate whiskers, the amount of the modifier is 2-8% by weight, and the amount of the basic magnesium sulfate whiskers is 92-98% by weight; preferably, based on the total weight of the surface-modified basic magnesium sulfate whiskers, the amount of the modifier is 4-6% by weight, and the amount of the basic magnesium sulfate whiskers is 94-96% by weight.

[0023] According to the present invention, the method for preparing the surface-modified basic magnesium sulfate whiskers includes:

[0024] (1) Modifier pretreatment: The modifier is dissolved in a mixture of ethanol and water;

[0025] (2) Treatment of basic magnesium sulfate whiskers: Basic magnesium sulfate whiskers are mixed with water to form a slurry, thus obtaining basic magnesium sulfate slurry;

[0026] (3) The hydrolysis product obtained in step (1) and the basic magnesium sulfate slurry obtained in step (2) are mixed, filtered and washed, and the resulting product is dried to obtain surface-modified basic magnesium sulfate whiskers.

[0027] In this invention, in step (1), the ratio of ethanol to water needs to be adjusted according to the different structures of the surface modifier. When the surface modifier is a silane coupling agent, the weight ratio of its amount to ethanol and water is 1:1:(17-22), and acetic acid is used to adjust the pH to 4-6. When the surface modifier is lauric acid, anhydrous ethanol is used until the surface modifier is completely dissolved. When the surface modifier is dodecyl monophosphate, pure water is used until the surface modifier is completely dissolved. Further, the mixing conditions include: a reaction temperature of 25-30°C and a reaction time of 3-6 hours.

[0028] In this invention, in step (2), magnesium sulfate whiskers are mixed with water at a ratio of 1:(40-60) to form a slurry, which is then sent to an ultrasonic cleaner for ultrasonic treatment for 0.5-2 hours and stirred for 4-6 hours to obtain magnesium sulfate slurry.

[0029] In this invention, in step (3), the mixing conditions include: mixing the hydrolysis product obtained in step (1) and the magnesium sulfate slurry obtained in step (2), reacting at 60-80°C for 1-2 hours, then filtering and washing, and drying the product in an oven at 40-60°C for 5-7 hours.

[0030] A second aspect of the present invention provides a polypropylene alloy material, wherein a 3mm square plate of the polypropylene alloy material has a light transmittance of 54-66%, a haze of 89-99.6%, and a notched impact strength of 21-41 kJ / m². 2The flexural modulus is 1500-1710 MPa; and the raw materials for preparing the polypropylene alloy material include polypropylene, toughening agent, POE compatibilizer and modified basic magnesium sulfate whiskers, wherein the modified basic magnesium sulfate whiskers are the aforementioned surface-modified basic magnesium sulfate whiskers.

[0031] According to the present invention, the polypropylene alloy material simultaneously meets the following performance requirements: a melt flow index of 9.2-15.1 g / 10 min at 230℃ and a load of 2.16 kg; a light transmittance of 54.4-65.3% for a 3 mm square plate; a haze of 89.2-99.6%; and a notched impact strength of 21.4-38.2 kJ / m². 2 The flexural modulus is 1500-1710 MPa; preferably, the light transmittance of the 3mm square plate of the polypropylene alloy material is 58.2-65.3%, and the notched impact strength is 22.4-36.2 kJ / m. 2 The flexural modulus is 1570-1680MPa, which further improves the rigidity-toughness balance and light transmission performance of the light-transmitting bumper.

[0032] The inventors of this invention discovered that the traditional development approach for translucent bumper products involves two aspects: First, high-rigidity homopolymer polypropylene is used as the base resin, combined with highly transparent and impact-resistant rubber to ensure a balance between rigidity and toughness. However, the styrene-based elastomers used in traditional patents have poor compatibility with polypropylene products compared to propylene-based elastomers. Therefore, propylene-based elastomers have an advantage in terms of light transmittance, but they do not significantly improve the impact resistance of the composite material, thus requiring the supplementation of transparent impact-resistant polypropylene. Second, transparent impact-resistant polypropylene has a similar light transmittance to homopolymer but higher impact resistance, which helps reduce the addition of elastomers, reducing costs and minimizing the impact on light transmittance. Furthermore, transparent impact-resistant polypropylene has a higher modulus than traditional transparent polypropylene, reducing the need for fillers in terms of rigidity and further minimizing the impact on light transmittance.

[0033] Based on this, the inventors of this invention discovered that, on the one hand, the surface-modified basic magnesium sulfate whiskers (modified basic magnesium sulfate whiskers) have improved compatibility with polypropylene, which can enhance the overall performance of the polypropylene / surface-modified magnesium sulfate whiskers / propylene-based elastomer alloy material. This polypropylene alloy material, relying on the ternary system of polypropylene / surface-modified magnesium sulfate whiskers / propylene-based elastomer, can ensure the material's transparency and a balance between rigidity and toughness.

[0034] On the other hand, the mechanical and optical properties of polypropylene alloy materials are limited due to the dispersion problem of basic magnesium sulfate whiskers (surface-modified basic magnesium sulfate whiskers) and toughening agents (propylene-based elastomers) within the system. Based on this, the inventors of this invention discovered that introducing maleic anhydride-grafted POE can undergo a ring-opening esterification reaction with surface-modified basic magnesium sulfate whiskers during processing, thereby forming a PP-surface-modified magnesium sulfate whisker-maleic anhydride-grafted POE-propylene-based elastomer bridge structure. This greatly enhances the compatibility of the system while ensuring that each component is fully dispersed within the alloy material, ultimately achieving the goal of improving overall performance.

[0035] Specifically, in the "propylene-based elastomer-maleic anhydride-grafted POE-surface-modified basic magnesium sulfate whiskers-polypropylene" bridge structure formed in the polypropylene alloy material system, the propylene-based elastomer is bonded to the POE compatibilizer through van der Waals forces, the POE compatibilizer is bonded to the base groups in the surface-modified basic magnesium sulfate whiskers through esterification reaction chemical bonds, and the silane groups in the surface-modified basic magnesium sulfate whiskers are bonded to the polypropylene through van der Waals forces, thereby forming a bridge structure.

[0036] On the one hand, surface modification of basic magnesium sulfate whiskers increases its compatibility with polypropylene (PP); on the other hand, its basic groups can further enhance its bonding force with elastomers through ring-opening esterification with maleic anhydride grafts. This bridge structure, under the dual influence of chemical bonds and van der Waals forces, greatly enhances the system's compatibility, thereby further improving the material's mechanical properties.

[0037] According to the present invention, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of polypropylene is 60-75% by weight, the amount of toughening agent is 2-18% by weight, the amount of POE compatibilizer is 2-18% by weight, and the amount of basic magnesium sulfate whiskers is 4-19% by weight; preferably, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of polypropylene is 67-71% by weight, the amount of toughening agent is 10-18% by weight, the amount of POE compatibilizer is 2-10% by weight, and the amount of basic magnesium sulfate whiskers is 8-12% by weight. In the present invention, if the toughening agent content is too high, the flexural modulus of the polypropylene alloy material will decrease significantly; if the POE compatibilizer content is too high, the flexural modulus and light transmittance of the polypropylene alloy material will decrease significantly simultaneously; if the basic magnesium sulfate whisker content is too high, the notched impact strength and light transmittance of the polypropylene alloy material will decrease significantly. Therefore, in this invention, by controlling the contents of polypropylene, toughening agent, POE compatibilizer and surface-modified basic magnesium sulfate whiskers within the above-mentioned range, the polypropylene alloy material applied to the bumper can simultaneously possess the characteristics of suitable melt index, high rigidity, high impact resistance and high light transmittance.

[0038] According to the present invention, the polypropylene has a melt index of 10-20 g / 10 min at 230°C and 2.16 kg load.

[0039] According to the present invention, preferably, the polypropylene is an impact-resistant copolymer polypropylene; more preferably, the impact-resistant copolymer polypropylene satisfies the following conditions: ethylene content of 4-8% by weight, xylene-soluble content of 16-19% by weight, average particle size of the rubber phase of 0.1-0.3 μm, and melt index of 15-20 g / 10 min at 230°C and 2.16 kg load. In the present invention, if the ethylene content and xylene-soluble content are high, the flexural modulus of the alloy material will decrease significantly; if they are too low, the notched impact strength of the alloy material will decrease significantly. If the average particle size of the rubber phase is too high, the light transmittance of the alloy material will decrease significantly. If the melt index is too high, the dispersibility of the polypropylene and other components will deteriorate due to the large difference in fluidity, resulting in poor overall material performance.

[0040] According to the present invention, the toughening agent is an propylene elastomer; preferably, the propylene elastomer has a melt index of 5-30 g / 10 min at 230°C and a load of 2.16 kg, more preferably 8-20 g / 10 min; and a density of 0.86-0.88 g / cm³. 3 The preferred value is 0.862-0.873 g / cm³. 3 .

[0041] According to the present invention, the POE compatibilizer is maleic anhydride-grafted POE; preferably, the melt index of the maleic anhydride-grafted POE at 190°C and 5kg load is 0.3-5g / 10min, more preferably 1-3g / 10min; the maleic anhydride grafting rate is 0.5-0.8% by weight, more preferably 0.6-0.7% by weight.

[0042] According to the present invention, the raw materials for preparing the polypropylene alloy material further include one or more of the following: a light-reflecting agent, a primary antioxidant, a secondary antioxidant, and a light stabilizer.

[0043] According to the present invention, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of the antireflectant is 0.1-0.2% by weight, the amount of the primary antioxidant is 0.1-0.3% by weight, the amount of the secondary antioxidant is 0.1-0.3% by weight, and the amount of the light stabilizer is 0.3-0.6% by weight; preferably, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of the antireflectant is 0.15-0.2% by weight, the amount of the primary antioxidant is 0.1-0.2% by weight, the amount of the secondary antioxidant is 0.2-0.3% by weight, and the amount of the light stabilizer is 0.4-0.5% by weight.

[0044] In this invention, it should be noted that the total amount of all components in the raw materials used to prepare the polypropylene alloy material is 100%.

[0045] A third aspect of the present invention provides a method for preparing the aforementioned polypropylene alloy material, wherein the method comprises:

[0046] (1) Mix polypropylene, toughening agent and POE compatibilizer to obtain premix;

[0047] (2) The premixed material and surface-modified basic magnesium sulfate whiskers are contacted in a twin-screw extruder for melting, extrusion and granulation to obtain polypropylene alloy material;

[0048] Wherein, the surface-modified basic magnesium sulfate whiskers are the aforementioned surface-modified basic magnesium sulfate whiskers;

[0049] The process conditions of the twin-screw extruder include: zone 1 feed temperature of 150-170℃, zone 2 pressure build-up temperature of 190-200℃, zone 3 pressure build-up temperature of 200-210℃, zone 4 melt temperature of 210-220℃, zone 5 exhaust temperature of 210-220℃, zone 6 conveying temperature of 210-220℃, zone 7 conveying temperature of 210-220℃, zone 8 pressure build-up temperature of 210-220℃, zone 9 pressure build-up temperature of 210-220℃, zone 10 pressure build-up temperature of 210-220℃, zone 11 devolatilization temperature of 210-220℃, zone 12 pressure build-up temperature of 210-220℃, die temperature of 200-210℃, and die head temperature of 190-200℃; the screw speed is 200-300 rpm.

[0050] According to the present invention, the method further includes:

[0051] (1) Mix polypropylene, toughening agent, POE compatibilizer, clearing agent, main antioxidant, auxiliary antioxidant and light stabilizer to obtain a premix;

[0052] (2) The premixed material and surface-modified basic magnesium sulfate whiskers are contacted in a twin-screw extruder for melting, extrusion and granulation to obtain polypropylene alloy material;

[0053] The process conditions of the twin-screw extruder include: zone 1 feed temperature of 150-170℃, zone 2 pressure build-up temperature of 190-200℃, zone 3 pressure build-up temperature of 200-210℃, zone 4 melt temperature of 210-220℃, zone 5 exhaust temperature of 210-220℃, zone 6 conveying temperature of 210-220℃, zone 7 conveying temperature of 210-220℃, zone 8 pressure build-up temperature of 210-220℃, zone 9 pressure build-up temperature of 210-220℃, zone 10 pressure build-up temperature of 210-220℃, zone 11 devolatilization temperature of 210-220℃, zone 12 pressure build-up temperature of 210-220℃, die temperature of 200-210℃, and die head temperature of 190-200℃; the screw speed is 200-300 rpm.

[0054] According to the present invention, the method can be carried out in a twin-screw extruder.

[0055] The method comprises:

[0056] (1) Mix polypropylene, toughening agent (propylene-based elastomer), POE compatibilizer, clearing agent, main antioxidant, auxiliary antioxidant and light stabilizer in a high-speed mixer for 4-6 minutes to obtain a premix;

[0057] (2) The premixed material is transported to the loss-in-weight hopper and fed into the main feed port of the extruder using the loss-in-weight hopper. Surface-modified basic magnesium sulfate whiskers are added to the side feed port of the extruder through the loss-in-weight hopper.

[0058] (3) The premixed material is melted, plasticized, sheared, dispersed, extruded, and then traction, cooled, granulated and homogenized in a twin-screw extruder to obtain the polypropylene alloy for the light-transmitting bumper;

[0059] The process conditions for the twin-screw extruder are as follows: screw length-to-diameter ratio is 48:1; temperature in zone 1 (feeding zone) is 150-170℃; temperature in zone 2 (pressure building zone) is 190-200℃; temperature in zone 3 (pressure building zone) is 200-210℃; melting temperature in zone 4 is 210-220℃; exhaust temperature in zone 5 is 210-220℃; conveying temperature in zone 6 is 210-220℃; conveying temperature in zone 7 is 210-220℃; pressure building temperature in zone 8 is 210-220℃; pressure building temperature in zone 9 is 210-220℃; pressure building temperature in zone 10 is 210-220℃; temperature in zone 11 (devouring zone) is 210-220℃; pressure building temperature in zone 12 is 210-220℃; die temperature is 200-210℃; die head temperature is 190-200℃; and screw speed is 200-300 rpm. The vacuum negative pressure is -0.075 to -0.08 MPa.

[0060] A fourth aspect of the present invention provides a polypropylene alloy material prepared by the method described above.

[0061] A fifth aspect of the present invention provides a bumper, wherein the bumper comprises the aforementioned polypropylene alloy material.

[0062] The present invention will be described in detail below through embodiments.

[0063] The raw materials used in the following examples and comparative examples are as follows:

[0064] #1 polypropylene (PP) is a transparent, impact-resistant polypropylene manufactured by China North Industries Group Corporation Limited (NORINCO), with the grade RC20M. It has a weight-average molecular weight of 132,400 g / mol, an ethylene content of 4.5 wt%, a xylene-soluble content of 17.3 wt%, an average rubber phase particle size of 0.14 μm, and a melt index of 20 g / 10 min at 230℃ and a load of 2.16 kg.

[0065] Toughening agent #1 is a propylene-based elastomer manufactured by ExxonMobil, grade 3000, with a weight-average molecular weight of 200600 g / mol, a melt flow index of 8 g / 10 min at 230℃ and a load of 2.16 kg, and a density of 0.873 g / cm³. 3 ;

[0066] Toughening agent #2 is a propylene-based elastomer manufactured by ExxonMobil, brand name 6202, with a weight-average molecular weight of 137,100 g / mol, a melt index of 20 g / 10 min at 230°C and a load of 2.16 kg, and a density of 0.862 g / cm³. 3 ;

[0067] The POE compatibilizer is maleic anhydride-grafted POE, manufactured by Jiaxing Huawen Chemical Co., Ltd., with the brand name HW-401. The weight-average molecular weight is 343,100 g / mol, the melt index at 190℃ and 5 kg load is 2.5 g / 10 min, and the maleic anhydride grafting rate is 0.6% by weight.

[0068] The manufacturer of magnesium sulfate whiskers is Jiangxi Fengzhu New Material Technology Co., Ltd., and the grade is NP-YW2.

[0069] The modifier, methacryloxypropyltrimethoxysilane, is manufactured by Merck.

[0070] The brightening agent is an α-crystal nucleating agent, manufactured by Milliken Laboratories, USA, with the brand name NX8000K.

[0071] The main antioxidant is a hindered phenolic antioxidant, manufactured by BASF AG, Germany, and its brand name is 1010.

[0072] The auxiliary antioxidant is a phosphite antioxidant, manufactured by BASF AG, Germany, and its brand name is 168.

[0073] The light stabilizer is a hindered amine light stabilizer, manufactured by Anhui Xinxiu Chemical Co., Ltd., and its brand name is 5585.

[0074] The raw materials used in the following comparative examples are as follows:

[0075] #2 polypropylene is an impact copolymer polypropylene, manufactured by Sinopec Ningbo Zhenhai Refining & Chemical Co., Ltd., with the grade PPB-MP17-G, a weight-average molecular weight of 143,300 g / mol, an ethylene content of 12.1 wt%, a xylene-soluble content of 30.2 wt%, an average rubber phase particle size of 0.63 μm, and a melt flow index of 17 g / 10 min at 230℃ and a load of 2.16 kg.

[0076] #3 polypropylene is homopolymer polypropylene, manufactured by Sinopec Ningbo Zhenhai Refining & Chemical Co., Ltd., with the grade PPH-M17-G, a weight-average molecular weight of 142,800 g / mol, and a melt index of 17 g / 10 min at 230℃ and 2.16 kg load.

[0077] #4 polypropylene is random copolymer polypropylene, manufactured by Zhenhai Refining & Chemical Branch of China Petroleum & Chemical Corporation, with the grade K4912, a weight-average molecular weight of 165,300 g / mol, and a melt index of 12 g / 10 min at 230℃ and 2.16 kg load.

[0078] The talc powder manufacturer is Quanzhou Xufeng Powder Raw Materials Co., Ltd., and the brand name is BHS-1031.

[0079] The melt flow index was tested according to ISO 1133 "Determination of melt mass flow rate and melt volume flow rate of thermoplastics", with the test conditions being 230℃ / 2.16kg·10min.

[0080] The notched impact strength was tested according to ISO 180 "Determination of impact strength of plastic cantilever beams". The sample was 80 mm long, 10 mm wide and 4 mm thick.

[0081] The flexural modulus was tested according to ISO 178 "Plastics - Test for bending properties". The length of the sample was 80 mm, the width was 10 mm, and the thickness was 4 mm. The test rate was 2 mm / min.

[0082] The light transmittance was tested according to GB / T2410-2008 "Determination of light transmittance and haze of transparent plastics". The sample was 60mm long, 60mm wide and 3mm thick.

[0083] The haze was tested according to GB / T2410-2008 "Determination of light transmittance and haze of transparent plastics". The sample was 60mm long, 60mm wide and 3mm thick.

[0084] Preparation Example 1

[0085] Example 1 illustrates the preparation of methacryloyloxypropyltrimethoxysilane-modified basic magnesium sulfate whiskers.

[0086] (1) Methacryloxypropyltrimethoxysilane was added to a mixture of ethanol and water for hydrolysis. The weight ratio of methacryloxypropyltrimethoxysilane, ethanol and water was 1:1:18. Acetic acid was used to adjust the pH to about 5. The reaction time was 5 hours and the reaction temperature was 25°C.

[0087] (2) Simultaneously, the basic magnesium sulfate whiskers are treated: basic magnesium sulfate and water are mixed at a ratio of 1:50 to form a slurry, which is then sent to an ultrasonic cleaner for ultrasonic cleaning for 1 hour and stirred for 5 hours to obtain basic magnesium sulfate slurry.

[0088] (3) Finally, the product obtained in step (1) and the basic magnesium sulfate slurry obtained in step (2) are mixed and reacted at 60°C for 1 hour. After filtration and washing, the product is dried in an oven at 50°C for 6 hours to obtain a methacryloyloxypropyltrimethoxysilane modified basic magnesium sulfate whisker product. Based on the total weight of the methacryloyloxypropyltrimethoxysilane modified basic magnesium sulfate whisker, the content of the silane coupling agent is 5% by weight and the content of the basic magnesium sulfate whisker is 95% by weight.

[0089] Preparation Example 2

[0090] Example 1 illustrates the preparation of lauric acid-modified basic magnesium sulfate whiskers.

[0091] Surface-modified basic magnesium sulfate whiskers were prepared using the same method as in Preparation Example 1, except that in step (1), lauric acid was added to anhydrous ethanol and stirred to dissolve, with a weight ratio of lauric acid to anhydrous ethanol of 1:5.

[0092] The result was a lauric acid-modified basic magnesium sulfate whisker product, with the content of the silane coupling agent being 5% by weight and the content of the basic magnesium sulfate whisker being 95% by weight, based on the total weight of the lauric acid-modified basic magnesium sulfate whisker.

[0093] Preparation Example 3

[0094] Example 1 illustrates the preparation of dodecyl monophosphate modified basic magnesium sulfate whiskers.

[0095] Surface-modified basic magnesium sulfate whiskers were prepared using the same method as in Preparation Example 1, except that in step (1), dodecyl monophosphate was added to deionized water and stirred to dissolve, and the weight ratio of lauric acid to deionized water was 1:18.

[0096] The result was a dodecyl monophosphate modified basic magnesium sulfate whisker product, and based on the total weight of the dodecyl monophosphate modified basic magnesium sulfate whiskers, the content of the silane coupling agent was 5% by weight, and the content of the basic magnesium sulfate whiskers was 95% by weight.

[0097] Example 1

[0098] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0099] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #1 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 10 wt% of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1, 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0100] (1) Mix 1# polypropylene, 1# toughening agent (propylene-based elastomer), POE compatibilizer, clearing agent, main antioxidant, auxiliary antioxidant and light stabilizer in a high-speed mixer for 5 minutes to obtain a premix;

[0101] (2) The premixed material is transported to the loss-in-weight weighing hopper and fed into the main feed port of the extruder using the loss-in-weight weighing. The silane coupling agent modified basic magnesium sulfate whiskers prepared in Example 1 are added to the side feed port of the extruder through the loss-in-weight weighing.

[0102] (3) The premixed material is melted, plasticized, sheared, dispersed, extruded, traction, cooled, granulated, and homogenized in a twin-screw extruder to obtain a polypropylene alloy for a light-transmitting bumper; wherein, the twin-screw extruder process conditions are as follows: screw length-to-diameter ratio is 48:1, temperature of zone 1 feeding zone is 170℃, temperature of zone 2 pressure building zone is 190℃, temperature of zone 3 pressure building zone is 200℃, melting temperature of zone 4 is 210℃, exhaust temperature of zone 5 is 210℃, conveying temperature of zone 6 is 210℃, conveying temperature of zone 7 is 210℃, pressure building temperature of zone 8 is 210℃, pressure building temperature of zone 9 is 210℃, pressure building temperature of zone 10 is 210℃, die temperature is 200℃, die head temperature is 190℃; screw speed is 250rpm, and vacuum negative pressure is -0.075MPa.

[0103] Example 2

[0104] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0105] The transparent bumper polypropylene alloy material was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. The "1# toughening agent in Example 1" was changed to "2# toughening agent". The other components and their contents were the same as in Example 1. The polypropylene alloy material was prepared using the same method as in Example 1.

[0106] The result was a polypropylene alloy for a light-transmitting bumper.

[0107] Example 3

[0108] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0109] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0110] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #1 polypropylene, 10 wt% of #1 toughening agent, 10 wt% of POE compatibilizer, 10 wt% of modified basic magnesium sulfate whiskers, 0.1 wt% of transparency enhancer, 0.2 wt% of primary antioxidant, 0.2 wt% of secondary antioxidant, and 0.5 wt% of light stabilizer.

[0111] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0112] Example 4

[0113] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0114] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0115] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #1 polypropylene, 18 wt% of #1 toughening agent, 2 wt% of POE compatibilizer, 10 wt% of modified basic magnesium sulfate whiskers, 0.1 wt% of transparency enhancer, 0.2 wt% of primary antioxidant, 0.2 wt% of secondary antioxidant, and 0.5 wt% of light stabilizer.

[0116] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0117] Example 5

[0118] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0119] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0120] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 75 wt% of #1 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer, 4 wt% of modified basic magnesium sulfate whiskers, 0.1 wt% of clearing agent, 0.2 wt% of primary antioxidant, 0.2 wt% of secondary antioxidant, and 0.5 wt% of light stabilizer.

[0121] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0122] Example 6

[0123] This embodiment illustrates the preparation of the polypropylene alloy material for the light-transmitting bumper of the present invention.

[0124] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0125] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 60 wt% of #1 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer, 19 wt% of modified basic magnesium sulfate whiskers, 0.1 wt% of transparency enhancer, 0.2 wt% of primary antioxidant, 0.2 wt% of secondary antioxidant, and 0.5 wt% of light stabilizer.

[0126] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0127] Example 7

[0128] The transparent bumper polypropylene alloy material was prepared using the same method as in Example 1, except that the modified basic magnesium sulfate whiskers used were the lauric acid modified basic magnesium sulfate whiskers prepared in Example 2.

[0129] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0130] Example 8

[0131] The transparent bumper polypropylene alloy material was prepared using the same method as in Example 1, except that the modified basic magnesium sulfate whiskers used were the dodecyl monophosphate modified basic magnesium sulfate whiskers prepared in Example 3.

[0132] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0133] Comparative Example 1

[0134] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0135] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #2 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 10 wt% of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1, 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0136] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0137] Comparative Example 2

[0138] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0139] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #3 polypropylene (homopolymer polypropylene, without rubber phase), 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 10 wt% of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1, 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0140] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0141] Comparative Example 3

[0142] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the components and their amounts in the raw materials for preparing the polypropylene alloy material were different from those in Example 1. Specifically:

[0143] The raw materials for preparing polypropylene alloy materials include the following components in the following amounts: 69 wt% of #4 polypropylene (random copolymer polypropylene, without rubber phase), 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 10 wt% of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1, 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0144] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0145] Comparative Example 4

[0146] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that no POE compatibilizer (maleic anhydride-grafted POE) was added; that is, the amount of POE compatibilizer (maleic anhydride-grafted POE) used was 0. The specific amounts of each component in the raw materials for preparing the polypropylene alloy material included:

[0147] The composition includes: 69 wt% polypropylene #1, 20 wt% toughening agent #1, 10 wt% silane coupling agent modified basic magnesium sulfate whiskers prepared in Example 1, 0.1 wt% clearing agent (α-crystal nucleating agent), 0.2 wt% primary antioxidant (hindered phenolic antioxidant), 0.2 wt% secondary antioxidant (phosphite antioxidant), and 0.5 wt% light stabilizer (hindered amine light stabilizer).

[0148] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0149] Comparative Example 5

[0150] The transparent polypropylene alloy material for the bumper was prepared using the same method as in Example 1, except that the content of the silane coupling agent in the modified basic magnesium sulfate whiskers prepared in Example 1 was different from that in Example 1. Specifically:

[0151] Based on the total weight of the silane coupling agent modified basic magnesium sulfate whiskers, the content of the silane coupling agent is 9% by weight, and the content of the basic magnesium sulfate whiskers is 91% by weight.

[0152] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0153] Comparative Example 6

[0154] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1 were not added; that is, the amount of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1 was 0. The specific amounts of each component in the raw materials for preparing the polypropylene alloy material included:

[0155] 69 wt% of #1 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 10 wt% of talc, 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0156] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0157] Comparative Example 7

[0158] The transparent polypropylene alloy material for the bumper was prepared using the same method as in Example 1, except that the content of the silane coupling agent in the modified basic magnesium sulfate whiskers prepared in Example 1 was different from that in Example 1. Specifically:

[0159] Based on the total weight of the silane coupling agent modified basic magnesium sulfate whiskers, the content of the silane coupling agent is 1% by weight, and the content of the basic magnesium sulfate whiskers is 99% by weight.

[0160] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0161] Comparative Example 8

[0162] The polypropylene alloy material for the light-transmitting bumper was prepared using the same method as in Example 1, except that the silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1 were not added; that is, the amount of silane coupling agent-modified basic magnesium sulfate whiskers prepared in Example 1 was 0. The specific amounts of each component in the raw materials for preparing the polypropylene alloy material included:

[0163] 79 wt% of #1 polypropylene, 15 wt% of #1 toughening agent, 5 wt% of POE compatibilizer (maleic anhydride-grafted POE), 0.1 wt% of penetration enhancer (α-crystal nucleating agent), 0.2 wt% of primary antioxidant (hindered phenolic antioxidant), 0.2 wt% of secondary antioxidant (phosphite antioxidant), and 0.5 wt% of light stabilizer (hindered amine light stabilizer).

[0164] Polypropylene alloy material was prepared using the same method as in Example 1, resulting in a polypropylene alloy for a light-transmitting bumper.

[0165] Test case

[0166] The properties of the polypropylene alloys prepared in Examples 1-8 and Comparative Examples 1-8 were tested, and the results are shown in Tables 1 and 2.

[0167] Table 1

[0168]

[0169]

[0170] Table 2

[0171]

[0172] The results above show that:

[0173] Compared with Example 1, Example 2 used a propylene-based elastomer with a high melt index, which increased the melt index of the alloy material accordingly, but reduced its impact performance.

[0174] Examples 3-6 describe the effects of different ratios of modified basic magnesium sulfate whiskers, toughening agents, and POE compatibilizers on the performance of composite materials, so as to make them suitable for different applications.

[0175] Examples 7-8 show that basic magnesium sulfate whiskers were modified with different surface modifiers. Compared with basic magnesium sulfate whiskers modified with lauric acid and dodecyl monophosphate, the basic magnesium sulfate whiskers modified with silane coupling agent showed better flexural modulus and impact strength after being added to the alloy material. The basic magnesium sulfate whiskers modified with the three surface modifiers could all meet the performance requirements of the composite material.

[0176] Compared with Example 1, Comparative Example 1 uses impact-resistant copolymer polypropylene. Due to the high xylene-soluble content of impact-resistant polypropylene, the impact resistance of the product is improved to a certain extent, but the flexural modulus decreases accordingly, making it difficult to meet the requirements. In addition, due to the large average particle size of the rubber phase of impact-resistant copolymer polypropylene and its low transparency, the light transmittance of the product is low.

[0177] Compared with Example 1, Comparative Example 2 uses homopolymer polypropylene. Since it does not contain a rubber phase, although the light transmittance of the alloy material is basically the same as that of Example 1, the impact performance is worse and it is difficult to meet the requirements.

[0178] Compared with Example 1, Comparative Example 3 uses random copolymer polypropylene. Although the light transmittance of the alloy material is higher than that of Example 1, the impact performance and flexural modulus are difficult to meet the requirements due to the poor mechanical properties of random copolymer polypropylene.

[0179] Compared with Example 1, Comparative Example 4 used only propylene-based elastomer, resulting in a product with poorer flexural modulus and impact strength compared to Example 1. This is partly due to the limited toughening effect of propylene-based elastomer itself, and partly due to its poor compatibility with magnesium sulfate whiskers, resulting in poor interphase bonding and a decrease in modulus.

[0180] Compared to Example 1, the amount of silane coupling agent added in the silane coupling agent modified basic magnesium sulfate used in Comparative Example 5 was relatively large, making it difficult to meet the performance requirements. This is because a large amount of silane coupling agent will result in some silane molecules not being coupled. The steric hindrance between these uncoupled silane molecules increases, leading to poor overall compatibility between the whiskers and polypropylene, and a decrease in performance.

[0181] Compared with Example 1, Comparative Example 6 used transparent talc powder as a filler, resulting in a decrease in light transmittance and a significant increase in haze, while no significant change was observed in mechanical properties.

[0182] Compared to Example 1, the amount of silane coupling agent added in the silane coupling agent modified basic magnesium sulfate used in Comparative Example 7 was relatively small, making it difficult to meet the performance requirements. This is because when the amount of silane coupling agent added is small, the silane molecules cannot completely couple the whisker sites of basic magnesium sulfate, resulting in insufficient overall oleophilicity. Consequently, the compatibility with polypropylene deteriorates, and the performance decreases.

[0183] Compared with Example 1, Comparative Example 8 does not contain talc or basic magnesium sulfate whiskers, and the overall flexural modulus of the unfilled material is significantly reduced, making it difficult to meet the performance requirements.

[0184] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A surface-modified basic magnesium sulfate whisker, characterized in that, The surface-modified basic magnesium sulfate whiskers are obtained by surface modification of basic magnesium sulfate whiskers using a modifier, which is one or more of methacryloyloxypropyltrimethoxysilane, lauric acid, and dodecyl monophosphate.

2. The surface-modified basic magnesium sulfate whiskers according to claim 1, wherein, The modifier is methacryloyloxypropyltrimethoxysilane.

3. The surface-modified basic magnesium sulfate whiskers according to claim 1 or 2, wherein, Based on the total weight of the surface-modified basic magnesium sulfate whiskers, the amount of the modifier is 2-8% by weight, and the amount of the basic magnesium sulfate whiskers is 92-98% by weight. Preferably, based on the total weight of the surface-modified basic magnesium sulfate whiskers, the amount of the modifier is 4-6% by weight, and the amount of the basic magnesium sulfate whiskers is 94-96% by weight.

4. A polypropylene alloy material, characterized in that, The 3mm square plate of the polypropylene alloy material has a light transmittance of 54-66%, a haze of 89-99.6%, and a notched impact strength of 21-41 kJ / m². 2 The flexural modulus is 1500-1710 MPa; and the raw materials for preparing the polypropylene alloy material include polypropylene, toughening agent, POE compatibilizer and surface-modified basic magnesium sulfate whiskers, wherein the surface-modified basic magnesium sulfate whiskers are the surface-modified basic magnesium sulfate whiskers as described in any one of claims 1-3.

5. The polypropylene alloy material according to claim 4, wherein, The polypropylene alloy material simultaneously meets the following performance requirements: a melt flow index of 9.2-15.1 g / 10 min at 230℃ and a load of 2.16 kg; a light transmittance of 54.4-65.3% for a 3 mm square plate; a haze of 89.2-99.6%; and a notched impact strength of 21.4-38.2 kJ / m². 2 The flexural modulus is 1500-1710 MPa; Preferably, the 3mm square plate of the polypropylene alloy material has a light transmittance of 58.2-65.3% and a notched impact strength of 22.4-36.2 kJ / m². 2 Its flexural modulus is 1570-1680 MPa.

6. The polypropylene alloy material according to claim 4 or 5, wherein, Based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of polypropylene is 60-75% by weight, the amount of toughening agent is 2-18% by weight, the amount of POE compatibilizer is 2-18% by weight, and the amount of basic magnesium sulfate whiskers is 4-19% by weight. Preferably, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of polypropylene is 67-71% by weight, the amount of toughening agent is 10-18% by weight, the amount of POE compatibilizer is 2-10% by weight, and the amount of basic magnesium sulfate whiskers is 8-12% by weight.

7. The polypropylene alloy material according to claim 4 or 6, wherein, The polypropylene has a melt flow index of 10-20 g / 10 min at 230°C and 2.16 kg load. Preferably, the polypropylene is an impact-resistant copolymer polypropylene; More preferably, the impact-resistant copolymer polypropylene meets the following conditions: ethylene content is 4-8% by weight, xylene soluble content is 16-19% by weight, rubber phase average particle size is 0.1-0.3μm, and melt index is 15-20g / 10min at 230℃ and 2.16kg load.

8. The polypropylene alloy material according to claim 4 or 6, wherein, The toughening agent is an acrylic elastomer; Preferably, the propylene elastomer has a melt index of 5-30 g / 10 min at 230°C and a load of 2.16 kg; Preferably, the density of the propylene elastomer is 0.86-0.88 g / cm³. 3 ; And / or, the POE compatibilizer is maleic anhydride-grafted POE; Preferably, the maleic anhydride-grafted POE has a melt index of 0.3-5 g / 10 min at 190°C and a load of 5 kg, and a maleic anhydride grafting rate of 0.5-0.8% by weight.

9. The polypropylene alloy material according to any one of claims 4-8, wherein, The raw materials for preparing the polypropylene alloy material also include one or more of the following: a light-reflecting agent, a primary antioxidant, a secondary antioxidant, and a light stabilizer; Preferably, based on the total weight of the raw materials used to prepare the polypropylene alloy material, the amount of the anti-reflective agent is 0.1-0.2% by weight, the amount of the primary antioxidant is 0.1-0.3% by weight, the amount of the secondary antioxidant is 0.1-0.3% by weight, and the amount of the light stabilizer is 0.3-0.6% by weight.

10. A method for preparing polypropylene alloy materials, characterized in that, The method includes: (1) Mix polypropylene, toughening agent and POE compatibilizer to obtain premix; (2) The premixed material and surface-modified basic magnesium sulfate whiskers are contacted in a twin-screw extruder for melting, extrusion and granulation to obtain polypropylene alloy material; Wherein, the surface-modified basic magnesium sulfate whiskers are the surface-modified basic magnesium sulfate whiskers as described in any one of claims 1-3; The process conditions of the twin-screw extruder include: zone 1 feed temperature of 150-170℃, zone 2 pressure build-up temperature of 190-200℃, zone 3 pressure build-up temperature of 200-210℃, zone 4 melt temperature of 210-220℃, zone 5 exhaust temperature of 210-220℃, zone 6 conveying temperature of 210-220℃, zone 7 conveying temperature of 210-220℃, zone 8 pressure build-up temperature of 210-220℃, zone 9 pressure build-up temperature of 210-220℃, zone 10 pressure build-up temperature of 210-220℃, zone 11 devolatilization temperature of 210-220℃, zone 12 pressure build-up temperature of 210-220℃, die temperature of 200-210℃, and die head temperature of 190-200℃; the screw speed is 200-300 rpm.

11. The method according to claim 10, wherein, The method further includes: (1) Mix polypropylene, toughening agent, POE compatibilizer, clearing agent, main antioxidant, auxiliary antioxidant and light stabilizer to obtain a premix; (2) The premixed material and surface-modified basic magnesium sulfate whiskers are contacted in a twin-screw extruder for melting, extrusion and granulation to obtain polypropylene alloy material; The process conditions of the twin-screw extruder include: zone 1 feed temperature of 150-170℃, zone 2 pressure build-up temperature of 190-200℃, zone 3 pressure build-up temperature of 200-210℃, zone 4 melt temperature of 210-220℃, zone 5 exhaust temperature of 210-220℃, zone 6 conveying temperature of 210-220℃, zone 7 conveying temperature of 210-220℃, zone 8 pressure build-up temperature of 210-220℃, zone 9 pressure build-up temperature of 210-220℃, zone 10 pressure build-up temperature of 210-220℃, zone 11 devolatilization temperature of 210-220℃, zone 12 pressure build-up temperature of 210-220℃, die temperature of 200-210℃, and die head temperature of 190-200℃; the screw speed is 200-300 rpm.

12. A polypropylene alloy material prepared by the method of claim 10 or 11.

13. A bumper, characterized in that, The bumper comprises the polypropylene alloy material as described in any one of claims 4-8 and 12.

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