A high-impact low-temperature-resistant polypropylene composite material and a preparation method thereof

Abstract

This invention belongs to the technical field of polypropylene composite materials and discloses a high-impact, low-temperature resistant polypropylene composite material and its preparation method. The high-impact, low-temperature resistant polypropylene composite material of this invention, by weight, comprises 100 parts of PP resin, 20-30 parts of EPDM elastomer rubber, 10-20 parts of EDPM-g-MAH, 8-12 parts of carbon black, 4-6 parts of KH550 coupling agent, 2-5 parts of dioctyl terephthalate, 2-6 parts of lubricant, and 1-3 parts of compatibilizer. This material is prepared by grafting maleic anhydride end groups onto modified carbon black to generate a corresponding carbon black-EPDM-g-MAH elastomer. The carbon black-EPDM-g-MAH elastomer is then blended with EPDM to obtain a mixed toughening agent. This mixed toughening agent has good compatibility with the polypropylene matrix, improving the impact toughness of polypropylene while minimizing the decrease in its tensile strength and other mechanical properties. Simultaneously, the presence of carbon black promotes the formation of β-crystals in polypropylene, further enhancing the toughness and low-temperature resistance of the polypropylene material.

Description

Technical Field

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

[0002] In recent years, polymer materials have become indispensable in various fields both domestically and internationally, and the application of general-purpose plastics has become increasingly widespread worldwide. Polypropylene (PP) is one of the four major general-purpose thermoplastic resins, possessing excellent physical and chemical properties such as lightweight, corrosion resistance, wear resistance, and high-temperature resistance, thus finding wide application in various fields. However, pure PP materials have poor impact resistance, especially at low temperatures. When used in high-latitude, low-temperature regions, PP materials are prone to low-temperature brittle fracture, significantly affecting their service life and application range. Therefore, improving the low-temperature impact resistance of PP materials has become an important research topic in this field.

[0003] Conventional methods for toughening and modifying PP include dynamic vulcanization, increasing the β-PP crystal content, and rigid particle toughening. It is well known that due to PP's excellent thermoplastic processing properties, the most convenient method for toughening PP is to incorporate elastomers during processing for blending modification. Simultaneously, to improve the compatibility between PP and the elastomer, the added elastomer needs to be modified to enhance PP's impact resistance while maintaining its tensile strength and other mechanical properties. However, how to modify PP to obtain high-impact, low-temperature resistant PP materials still requires further research and exploration. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a high-impact, low-temperature resistant polypropylene composite material and its preparation method. This method uses ethylene propylene diene monomer (EPDM) rubber, which has good toughening and low-temperature resistance properties. Maleic anhydride end groups are grafted onto EPDM rubber, and modified carbon black is reacted to generate a corresponding carbon black-EPDM-g-MAH elastomer. The carbon black-EPDM-g-MAH elastomer is then blended with EPDM to obtain a mixed toughening agent. This mixed toughening agent has good compatibility with the polypropylene matrix, improving the impact toughness of polypropylene while minimizing the decrease in its tensile strength and other mechanical properties. Simultaneously, the presence of carbon black promotes the formation of the β-crystal form in polypropylene, further enhancing the toughness and low-temperature resistance of the polypropylene material.

[0005] To achieve the objectives of this invention, the preparation method of the high-impact, low-temperature resistant polypropylene composite material of this invention includes the following steps:

[0006] (1) 3-aminopropyltriethoxysilane (KH550) was added to a mixed solvent of anhydrous ethanol and deionized water and ultrasonically hydrolyzed to obtain a 3-aminopropyltrihydroxysilane solution. Carbon black was added to water to form a carbon black dispersion, ultrasonicated, and ammonia was added to adjust the pH. The obtained 3-aminopropyltrihydroxysilane solution was then added to the carbon black dispersion, heated, stirred and reacted, filtered, washed and dried to obtain modified carbon black.

[0007] (2) The modified carbon black prepared in step (1) is mixed with EPDM-g-MAH to obtain carbon black-EPDM-g-MAH elastomer;

[0008] (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM and melt-blended to obtain a mixed toughening agent;

[0009] (4) The mixed toughening agent in step (3) is extruded and granulated with PP and other additives to finally obtain high impact resistance and low temperature resistant polypropylene.

[0010] Furthermore, in some embodiments of the present invention, the volume ratio of 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol in step (1) is 1:2:5 to 1:4:7.

[0011] Furthermore, in some embodiments of the present invention, the pH value of the 3-aminopropyltrihydroxysilane solution in step (1) is 3.5 to 4.5.

[0012] Furthermore, in some embodiments of the present invention, the ultrasonic hydrolysis time in step (1) is 4h~7h.

[0013] Furthermore, in some embodiments of the present invention, the mass ratio of carbon black to water in step (1) is between 1:2 and 1:10 (preferably 1:6 to 8), the ultrasonic time after forming the carbon black dispersion is 8 to 12 hours, and ammonia water is added to adjust the pH to 9 to 11.

[0014] Furthermore, in some embodiments of the present invention, the mass ratio of 3-aminopropyltriethoxysilane to carbon black in step (1) is between 1:1.5 and 1:4.0; preferably, the mass ratio of 3-aminopropyltriethoxysilane to carbon black in step (1) is between 1:1.5 and 1:2.5.

[0015] Furthermore, in some embodiments of the present invention, the temperature in step (1) is heated to 20~40°C.

[0016] Furthermore, in some embodiments of the present invention, the stirring reaction time in step (1) is 8 to 12 hours.

[0017] Furthermore, in some embodiments of the present invention, the detergent used for washing in step (1) is a mixed solution of anhydrous ethanol and deionized water, with a volume ratio of 5:1 to 9:1 (preferably 6 to 8:1).

[0018] Furthermore, in some embodiments of the present invention, the drying temperature in step (1) is 50~60℃ and the drying time is 24~36h.

[0019] Furthermore, in some embodiments of the present invention, the mass ratio of modified carbon black to EPDM-g-MAH in step (2) is 1:1.5 to 1:2.5.

[0020] Furthermore, in some embodiments of the present invention, the mixing in step (2) is carried out in a two-roll mill. Preferably, the roller speed of the two-roll mill is 4~26 rpm, the roller temperature is 30~60℃ (preferably 45~55℃), and the mixing time is 20~40 min.

[0021] Furthermore, in some embodiments of the present invention, in step (2), EPDM-g-MAH is maleic anhydride grafted onto EPDM.

[0022] Furthermore, in some embodiments of the present invention, the pure EPDM in step (3) is a terpolymer of ethylene, propylene and non-conjugated diene, wherein the ethylene (molar fraction) content is 25%~75% (preferably 55%~65%).

[0023] Furthermore, in some embodiments of the present invention, the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM in step (3) is 1:1.5 to 1:2.5.

[0024] Furthermore, in some embodiments of the present invention, the melt blending in step (3) is carried out in a two-roll open mill; preferably, the roller speed of the two-roll open mill is 4~26 rpm, the roller temperature is 30~60℃ (preferably 35~45℃), and the melt blending time is 2~4 min.

[0025] Furthermore, in some embodiments of the present invention, the other additives in step (4) are plasticizers, lubricants and compatibilizers; preferably, the mass ratio of the PP resin, mixed toughening agent, plasticizer, lubricant and compatibilizer is 100:35~45:1~5:2~6:1~3.

[0026] Furthermore, in some embodiments of the present invention, the extrusion granulation in step (4) is performed in a twin-screw extruder. Preferably, the main feed rate of the twin-screw extruder is 5.8~6.3 kg / h, the side feed rate is 2.5~3.7 kg / h, the extruder temperature is between 210~240℃, and the screw speed is 80~85 rpm. Most preferably, the main feed rate is 5.8~6.2 kg / h, the side feed rate is 3.1~3.5 kg / h, and the extruder temperature is between 215~225℃.

[0027] Further, in some embodiments of the present invention, PP in step (4) is homopolymer propylene; preferably, the plasticizer is selected from one or more combinations of dioctyl phthalate, dioctyl terephthalate, and di(2-ethylhexyl) phthalate; more preferably, the plasticizer is dioctyl terephthalate; preferably, the lubricant is a mixture of HSt and ZnSt2, and the molar ratio of HSt to ZnSt2 is 1.5:1 to 4.5:1 (more preferably 2.5 to 3.5:1); preferably, the compatibilizer is liquid paraffin.

[0028] Furthermore, the present invention also provides a high-impact, low-temperature resistant polypropylene composite material, which is prepared by the aforementioned method.

[0029] Furthermore, the present invention also provides a high-impact, low-temperature resistant polypropylene composite material, which, by weight, comprises 100 parts of PP resin, 20-30 parts of EPDM elastomer rubber, 10-20 parts of EDPM-g-MAH, 8-12 parts of carbon black, 4-6 parts of KH550 coupling agent, 2-5 parts of dioctyl terephthalate, 2-6 parts of lubricant, and 1-3 parts of compatibilizer.

[0030] Compared with existing technologies, this invention introduces carbon black into EPDM, which not only improves the compatibility between the elastomer and the matrix polypropylene, but also enhances the impact resistance and low-temperature resistance of polypropylene. Simultaneously, the presence of carbon black promotes the formation of β-crystals in polypropylene, further improving its impact resistance and low-temperature resistance. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the KH550 modified carbon black of the present invention, wherein, It is carbon black;

[0032] Figure 2 This is the chemical reaction formula between the modified carbon black and EPDM-g-MAH of this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. It should be understood that the following description is merely illustrative and not intended to limit the invention.

[0034] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0035] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0036] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0037] Furthermore, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., described below refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0038] Example 1

[0039] The preparation method of modified polypropylene is as follows:

[0040] (1) 2.21 g of 3-aminopropyltriethoxysilane was added to a mixed solvent of 28.8 mL of anhydrous ethanol and 14.4 mL of deionized water, wherein the volume ratio of 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol was 1:3:6. The mixed solution was sonicated at 24 °C for 5 h to hydrolyze and generate a 3-aminopropyltrihydroxysilane solution. 4.40 g of carbon black was added to 30 mL of water to form a dispersion, sonicated for 10 h, and ammonia was added to adjust the pH to 10. The 3-aminopropyltrihydroxysilane solution was added to the carbon black dispersion, heated to 35 °C and stirred for 10 h, filtered, washed with a 7:1 mixture of anhydrous ethanol and deionized water, and dried at 55 °C for 30 h to obtain modified carbon black.

[0041] (2) The modified carbon black prepared in step (1) and commercially available EPDM-g-MAH are mixed in a 1:2 ratio in a two-roll mill. The roller speed is 20 rpm and the roller temperature is 50℃. After mixing for 30 min, the modified carbon black and EPDM-g-MAH undergo a chemical reaction to obtain carbon black-EPDM-g-MAH elastomer.

[0042] (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM (ethylene content 60%), and the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM is 1:2. The roller speed is 20 rpm, the temperature is 40℃, and the mixing time is controlled at 3 min. The mixture is melt-blended in a two-roll mill to obtain a mixed toughening agent.

[0043] (4) The ratio of PP: mixed toughening agent: dioctyl terephthalate: stearic acid / zinc stearate (3:1): liquid paraffin = 100:40:3:4:2 was added to a twin-screw extruder for extrusion granulation. The main feed speed was controlled at 6 kg / h, the side feed speed at 3.3 kg / h, the extruder temperature at 220℃, and the screw speed at 84 rpm. Finally, high impact-resistant and low-temperature resistant polypropylene was obtained.

[0044] The modified polypropylene material formulation is as follows:

[0045] 100 parts PP resin, 25 parts EPDM elastomer rubber, 15 parts EDPM-g-MAH, 9 parts carbon black, 4.5 parts KH550 coupling agent, 3 parts dioctyl terephthalate, 3 parts stearic acid, 1 part zinc stearate, and 2 parts liquid paraffin.

[0046] Example 2

[0047] The preparation method of modified polypropylene is as follows:

[0048] (1) 2.21 g of 3-aminopropyltriethoxysilane was added to a mixed solvent of 28.8 mL of anhydrous ethanol and 14.4 mL of deionized water, wherein the volume ratio of 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol was 1:3:6. The mixed solution was sonicated at 24 °C for 5 h to hydrolyze and generate a 3-aminopropyltrihydroxysilane solution. 8.80 g of carbon black was added to 30 mL of water to form a dispersion, sonicated for 10 h, and ammonia was added to adjust the pH to 10. The 3-aminopropyltrihydroxysilane solution was added to the carbon black dispersion, heated to 35 °C, stirred for 10 h, filtered, washed with a 7:1 mixture of anhydrous ethanol and deionized water, and dried at 55 °C for 30 h to obtain modified carbon black.

[0049] (2) The modified carbon black prepared in step (1) and commercially available EPDM-g-MAH are mixed in a 1:2 ratio in a two-roll mill. The roller speed is 20 rpm and the roller temperature is 50℃. After mixing for 30 min, the modified carbon black and EPDM-g-MAH undergo a chemical reaction to obtain carbon black-EPDM-g-MAH elastomer.

[0050] (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM (ethylene content 60%), and the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM is 1:2. The roller speed is 20 rpm, the temperature is 40℃, and the mixing time is controlled at 3 min. The mixture is melt-blended in a two-roll mill to obtain a mixed toughening agent.

[0051] (4) The ratio of PP: mixed toughening agent: dioctyl terephthalate: stearic acid / zinc stearate (3:1): liquid paraffin = 100:40:3:4:2 was added to a twin-screw extruder for extrusion granulation. The main feed speed was controlled at 6 kg / h, the side feed speed at 3.3 kg / h, the extruder temperature at 220℃, and the screw speed at 84 rpm. Finally, high impact-resistant and low-temperature resistant polypropylene was obtained.

[0052] The modified polypropylene material formulation is as follows:

[0053] 100 parts PP resin, 25 parts EPDM elastomer rubber, 15 parts EDPM-g-MAH, 18 parts carbon black, 4.5 parts KH570 coupling agent, 3 parts dioctyl terephthalate, 3 parts stearic acid, 1 part zinc stearate, and 2 parts liquid paraffin.

[0054] Example 3

[0055] The preparation method of modified polypropylene is as follows:

[0056] (1) 4.42 g of 3-aminopropyltriethoxysilane was added to a mixed solvent of 57.6 mL of anhydrous ethanol and 28.8 mL of deionized water, wherein the volume ratio of 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol was 1:3:6. The mixed solution was sonicated at 24 °C for 5 h to hydrolyze and generate a 3-aminopropyltrihydroxysilane solution. 4.40 g of carbon black was added to 30 mL of water to form a dispersion, sonicated for 10 h, and ammonia was added to adjust the pH to 10. The 3-aminopropyltrihydroxysilane solution was added to the carbon black dispersion, heated to 35 °C and stirred for 10 h, filtered, washed with a 7:1 mixture of anhydrous ethanol and deionized water, and dried at 55 °C for 30 h to obtain modified carbon black.

[0057] (2) The modified carbon black prepared in step (1) and commercially available EPDM-g-MAH are mixed in a 1:2 ratio in a two-roll mill. The roller speed is 20 rpm and the roller temperature is 50℃. After mixing for 30 min, the modified carbon black and EPDM-g-MAH undergo a chemical reaction to obtain carbon black-EPDM-g-MAH elastomer.

[0058] (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM (ethylene content 60%), and the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM is 1:2. The roller speed is 20 rpm, the temperature is 40℃, and the mixing time is controlled at 3 min. The mixture is melt-blended in a two-roll mill to obtain a mixed toughening agent.

[0059] (4) The ratio of PP: mixed toughening agent: dioctyl terephthalate: stearic acid / zinc stearate (3:1): liquid paraffin = 100:40:3:4:2 was added to a twin-screw extruder for extrusion granulation. The main feed speed was controlled at 6 kg / h, the side feed speed at 3.3 kg / h, the extruder temperature at 220℃, and the screw speed at 84 rpm. Finally, high impact-resistant and low-temperature resistant polypropylene was obtained.

[0060] The modified polypropylene material formulation is as follows:

[0061] 100 parts PP resin, 25 parts EPDM elastomer rubber, 15 parts EDPM-g-MAH, 9 parts carbon black, 9 parts KH550 coupling agent, 3 parts dioctyl terephthalate, 3 parts stearic acid, 1 part zinc stearate, and 2 parts liquid paraffin.

[0062] Example 4

[0063] The preparation method of modified polypropylene is as follows:

[0064] (1) 2.48 g of γ-methacryloxypropyltrimethoxysilane (KH570) was added to a mixed solvent of 24.9 mL of anhydrous ethanol and 2.8 mL of deionized water, wherein the volume ratio of γ-methacryloxypropyltrimethoxysilane, deionized water and anhydrous ethanol was 1:1:9. The mixed solution was sonicated at 24 °C for 5 h to hydrolyze and generate a 3-aminopropyltrihydroxysilane solution. 4.40 g of carbon black was added to 30 mL of water to form a dispersion, sonicated for 10 h, and ammonia was added to adjust the pH to 10. The γ-methacryloxypropyltrimethoxysilane solution was added to the carbon black dispersion, heated to 35 °C, stirred for 10 h, filtered, washed with a 7:1 mixture of anhydrous ethanol and deionized water, and dried at 55 °C for 30 h to obtain modified carbon black.

[0065] (2) The modified carbon black prepared in step (1) and commercially available EPDM-g-MAH were mixed in a 1:2 ratio in a two-roll mill. The roller speed was 20 rpm, the roller temperature was 50℃, and the mixing time was 30 min. The modified carbon black and EPDM-g-MAH underwent a chemical reaction to obtain carbon black-EPDM-g-MAH elastomer.

[0066] (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM (ethylene content 60%), and the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM is 1:2. The roller speed is 20 rpm, the temperature is 40℃, and the mixing time is controlled at 3 min. The mixture is melt-blended in a two-roll mill to obtain a mixed toughening agent.

[0067] (4) The following mixture was added to a twin-screw extruder and extruded into granules in the following ratio: PP: mixed toughening agent: dioctyl terephthalate: stearic acid / zinc stearate (3:1): liquid paraffin = 100:40:3:4:2. The main feed rate was controlled at 6 kg / h, the side feed rate at 3.3 kg / h, the extruder temperature at 220℃, and the screw speed at 84 rpm. High-impact, low-temperature resistant polypropylene was finally obtained.

[0068] The modified polypropylene material formulation is as follows:

[0069] 100 parts PP resin, 25 parts EPDM elastomer rubber, 15 parts EDPM-g-MAH, 9 parts carbon black, 4.5 parts KH570 coupling agent, 3 parts dioctyl terephthalate, 3 parts stearic acid, 1 part zinc stearate, and 2 parts liquid paraffin.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that the preparation formula of the modified polypropylene is different (it does not contain mixed toughening agents, but only EPDM elastomer rubber). By mass parts, it contains: 100 parts PP resin, 15 parts EPDM elastomer rubber, 3 parts dioctyl terephthalate, 3 parts stearic acid, 1 part zinc stearate, and 2 parts liquid paraffin.

[0072] Example Performance Test Results

[0073] Performance testing: The tensile strength, elongation at break, impact strength, and low-temperature impact compression resistance of the composite polypropylene materials prepared in the examples and comparative examples were tested in accordance with the national standards GB / T 1040 Determination of Tensile Properties of Plastics, GB / T 1843 Determination of Impact Strength of Plastics Cantilever Beams, GB / T 9341 Test Method for Bending Properties of Plastics and HG / T 2-162-65 Low-Temperature Impact Compression Test of Plastics. The results are shown in Table 1.

[0074] Table 1. Results of performance testing of polypropylene composite materials

[0075] Sample Tensile strength (MPa) Elongation at break (%) <![CDATA[Impact strength (kJ / m 2 )]]> Low-temperature impact compression cold resistance temperature (°C) Example 1 48.31 148.6 23.7 -56.3 Example 2 44.32 137.8 22.1 -50.4 Example 3 42.67 122.4 19.8 -48.6 Example 4 40.27 117.3 14.8 -44.3 Comparative Example 1 38.08 76.5 7.58 -30.0

[0076] As can be seen from the above examples, the modified polypropylene prepared by adding the coupling agent modified carbon black provided by the present invention to EPDM-g-MAH has excellent tensile strength and impact strength, reaching up to 48.31 MPa and 23.7 KJ / m², respectively. 2 Furthermore, the elongation at break reaches 148.6%. The impact strength of the polypropylene composite material prepared using the KH550 coupling agent-modified carbon black synthesized in this invention is significantly superior to that of polypropylene with KH570 modified filler. The composite polypropylene sample prepared with the coupling agent-modified carbon black synthesized in this invention exhibits excellent low-temperature impact resistance, with a low-temperature impact compression resistance temperature reaching -56.3 ℃. The structure of KH550 modified carbon black is as follows... Figure 1 As shown, the chemical reaction formula between modified carbon black and EPDM-g-MAH is as follows: Figure 2 As shown.

[0077] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-impact, low-temperature resistant polypropylene composite material, characterized in that, The preparation method of the high-impact, low-temperature resistant polypropylene composite material includes the following steps: (1) 3-aminopropyltriethoxysilane was added to a mixed solvent of anhydrous ethanol and deionized water and ultrasonically hydrolyzed to obtain a 3-aminopropyltrihydroxysilane solution. Carbon black was added to water to form a carbon black dispersion, ultrasonicated, and ammonia was added to adjust the pH. The obtained 3-aminopropyltrihydroxysilane solution was then added to the carbon black dispersion, heated, stirred and reacted, filtered, washed and dried to obtain modified carbon black. (2) The modified carbon black prepared in step (1) is mixed with EPDM-g-MAH to obtain carbon black-EPDM-g-MAH elastomer; (3) The carbon black-EPDM-g-MAH elastomer obtained in step (2) is mixed with pure EPDM and melt-blended to obtain a mixed toughening agent; (4) The mixed toughening agent in step (3) is extruded and granulated with PP and other additives to finally obtain high impact-resistant and low-temperature resistant polypropylene; In step (1), the volume ratio of 3-aminopropyltriethoxysilane, deionized water, and anhydrous ethanol is 1:2:5 to 1:4:7; the ultrasonic hydrolysis time in step (1) is 4h to 7h; the mass ratio of carbon black to water in step (1) is between 1:2 and 1:10, and the ultrasonic time after forming the carbon black dispersion is 8 to 12h, and ammonia water is added to adjust the pH to 9 to 11; In step (1), the temperature is heated to 20-40°C; in step (1), the stirring reaction time is 8-12 hours; in step (1), the washing agent used is a mixed solution of anhydrous ethanol and deionized water, with a volume ratio of 5:1 to 9:1; in step (1), the drying temperature is 50-60°C and the drying time is 24-36 hours. In step (2), the mass ratio of modified carbon black to EPDM-g-MAH is 1:1.5~1:2.5; in step (2), the mixing is carried out in a two-roll mill, the roller speed of the two-roll mill is 4~26 rpm, the roller temperature is 30~60℃, and the mixing time is 20~40 min. In step (3), the pure EPDM is a terpolymer of ethylene, propylene and non-conjugated diene, wherein the ethylene content is 25%~75%; in step (3), the mass ratio of carbon black-EPDM-g-MAH elastomer to pure EPDM is 1:1.5~1:2.5; in step (3), the melt blending is carried out in a two-roll mill; the roller speed of the two-roll mill is 4~26 rpm, the roller temperature is 30~60℃, and the melt blending time is 2~4 min.

2. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 1, characterized in that, In step (1), the mass ratio of 3-aminopropyltriethoxysilane to carbon black is between 1:1.5 and 1:4.

0.

3. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 1, characterized in that, In step (1), the mass ratio of 3-aminopropyltriethoxysilane to carbon black is between 1:1.5 and 1:2.

5.

4. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 1, characterized in that, In step (2), EPDM-g-MAH is maleic anhydride grafted onto EPDM.

5. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 1, characterized in that, The other additives in step (4) are plasticizers, lubricants and compatibilizers; the mass ratio of the PP resin, mixed toughening agent, plasticizer, lubricant and compatibilizer is 100:35~45:1~5:2~6:1~3.

6. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 1, characterized in that, In step (4), the extrusion granulation is performed in a twin-screw extruder. The main feed rate of the twin-screw extruder is 5.8~6.3 kg / h, the side feed rate is 2.5~3.7 kg / h, the extruder temperature is between 210~240℃, and the screw speed is 80~85 rpm.

7. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 6, characterized in that, The main feed rate is 5.8~6.2 kg / h, the side feed rate is 3.1~3.5 kg / h, and the extruder temperature is between 215~225℃.

8. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 5, characterized in that, In step (4), PP is homopolymer propylene; the plasticizer is selected from one or more of dioctyl phthalate, dioctyl terephthalate, and di(2-ethylhexyl) phthalate.

9. The method for preparing the high-impact, low-temperature resistant polypropylene composite material according to claim 5, characterized in that, The plasticizer is dioctyl terephthalate; the lubricant is a mixture of HSt and ZnSt2, and the molar ratio of HSt to ZnSt2 is 1.5:1 to 4.5:1; the compatibilizer is liquid paraffin.

10. A high-impact, low-temperature resistant polypropylene composite material obtained by the preparation method of the high-impact, low-temperature resistant polypropylene composite material according to any one of claims 1-9.

Images