Polypropylene composite and method for its production and vehicle component

Abstract

This application discloses a polypropylene composite material. According to embodiments of this application, the polypropylene composite material, by mass percentage, comprises: polypropylene: 60%–70%; talc: 10%–20%; elastomer: 5%–10%; lignin: 1%–15%; stabilizer: 0.1%–1%; β-crystal nucleating agent: 0.01%–0.1%; other additives: 0%–3%; the stabilizer includes hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer. The polypropylene composite material proposed in this application is not easily aged or degraded, has good resistance to performance degradation, and a long service life, thereby improving service life and safety.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, specifically to polypropylene composite materials, their preparation methods, and vehicle parts. Background Technology

[0002] Polypropylene (PP) is lightweight and inexpensive, possessing good mechanical properties, processability, and heat resistance, making it one of the most widely used and consumed plastics in the automotive industry. However, due to the numerous unstable tertiary carbon atoms in its molecular chain, PP is susceptible to catalytic oxidation reactions during production, transportation, and use, triggered by heat, oxygen, and shear. These reactions occur through a series of free radical reactions, including chain initiation, chain transfer, and chain termination. Over time, PP develops defects in its appearance, and its physical and mechanical properties gradually deteriorate until it loses its original performance (aging degradation). This performance failure severely impacts vehicle safety and lifespan. Therefore, improving the anti-aging properties of PP is crucial for ensuring both material performance and driving safety. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in the related art. Therefore, one objective of this application is to provide a polypropylene composite material, a method for preparing the same, and vehicle components thereof. The polypropylene composite material of this application is not easily aged or degraded, has good resistance to performance degradation, and a long service life, thereby improving service life and safety.

[0004] The first aspect of this application discloses a polypropylene composite material. According to embodiments of this application, the polypropylene composite material, by mass percentage, comprises the following components:

[0005] Polypropylene: 60%–70%;

[0006] Talc: 10%–20%;

[0007] Elastomer: 5%–10%;

[0008] Lignin: 1%–15%;

[0009] Stabilizer: 0.1%–1%;

[0010] β-crystal nucleating agent: 0.01%–0.1%;

[0011] Other additives: 0%–3%;

[0012] Stabilizers include hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers.

[0013] The embodiments of this application utilize a combination of β-crystal nucleating agent, high-performance stabilizer, and lignin, ensuring that each component meets the aforementioned mass ratio, thereby achieving a highly efficient synergistic effect. This provides efficient and continuous stabilization of free radicals, delaying the aging and degradation process of polypropylene, mitigating the decline in the mechanical properties of polypropylene materials, and improving the long-term service life of polypropylene materials.

[0014] The second aspect of this application discloses a method for preparing a polypropylene composite material, comprising:

[0015] The raw materials polypropylene, talc, elastomer, lignin, stabilizer, β-crystal nucleating agent and other additives are mixed to obtain a mixture.

[0016] The mixture is melt-extruded, cooled, granulated, and dried to obtain a polypropylene composite material;

[0017] The raw material composition, by weight percentage, includes:

[0018] Polypropylene: 60%–70%;

[0019] Talc: 10%–20%;

[0020] Elastomer: 5%–10%;

[0021] Lignin: 1%–15%;

[0022] Stabilizer: 0.1%–1%;

[0023] β-crystal nucleating agent: 0.02%–0.1%;

[0024] Other additives: 0%–3%;

[0025] Stabilizers include hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers.

[0026] The second aspect of this application discloses a vehicle component comprising the aforementioned polypropylene composite material, or comprising a polypropylene composite material prepared by the aforementioned method.

[0027] The polypropylene composite material prepared by the method of this application can delay the aging and degradation process of polypropylene, slow down the decline of the mechanical properties of polypropylene, and improve the long-term service life of polypropylene.

[0028] The vehicle components provided in this application embodiment include the aforementioned polypropylene composite material, which has high safety and a long service life.

[0029] Additional aspects and advantages of this application 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 this application. Detailed Implementation

[0030] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0031] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0032] The endpoints and any values ​​of the ranges disclosed in this application 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 in this application.

[0033] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0034] Because polypropylene (PP) molecules contain many unstable tertiary carbon atoms, PP materials are susceptible to catalytic oxidation reactions during production, transportation, and use due to the effects of heat, oxygen, and shear. This oxidation is triggered by a series of free radical reactions, including chain initiation, chain transfer, and chain termination. Over time, PP materials develop defects in appearance, and their physical and mechanical properties gradually deteriorate until they lose their original properties (aging degradation). This performance failure of PP materials will severely impact the safety and lifespan of automobiles during operation.

[0035] The causes of polypropylene (PP) aging and degradation are highly complex. Numerous studies have shown that the molecular chain structure, aggregate structure, modification properties, processing aids, and processing parameters of PP all influence its aging and degradation behavior. Based on a deep understanding of the aging and stabilization mechanisms of PP, many effective anti-aging measures have been proposed. Among these, in industrial production, adding antioxidants can effectively improve the anti-aging and performance properties of PP materials. For example, traditional antioxidants such as 168, 1010, and 1076 are used to improve the anti-aging properties of PP materials. However, traditional antioxidants have poor thermal stability and are prone to decomposition within the PP processing temperature window; they also have poor compatibility with the PP matrix, easily migrating and precipitating during use. This results in a weak antioxidant effect on PP, ultimately leading to rapid performance degradation and poor long-term performance of the PP material. In addition, other modifiers and fillers have poor compatibility with polypropylene, which will affect its dispersibility in the melt. Since other modifiers and fillers have a certain adsorption effect on antioxidants and light stabilizers, they will further affect the antioxidant effect of antioxidants and light stabilizers, thereby affecting the anti-aging performance of polypropylene.

[0036] Therefore, the first aspect of this application provides a polypropylene composite material. According to an embodiment of this application, a polypropylene composite material, by mass percentage, comprises the following components:

[0037] Polypropylene: 60%–70%;

[0038] Talc: 10%–20%;

[0039] Elastomer: 5%–10%;

[0040] Lignin: 1%–15%;

[0041] Stabilizer: 0.1%–1%;

[0042] β-crystal nucleating agent: 0.01%–0.1%;

[0043] Other additives: 0%–3%;

[0044] Stabilizers include hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers.

[0045] In specific examples, the lignin content is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc. The stabilizer content is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc. The β-crystal nucleating agent content is 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, etc.

[0046] In specific examples, the polypropylene content is 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, etc.; the talc content is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%; and the elastomer content is 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0047] The embodiments of this application utilize a combination of β-crystal nucleating agent, high-performance stabilizer, and lignin, ensuring that each component meets the aforementioned mass ratio, thereby achieving a highly efficient synergistic effect. This provides efficient and continuous stabilization of free radicals, delaying the aging and degradation process of polypropylene, mitigating the decline in the mechanical properties of polypropylene materials, and improving the long-term service life of polypropylene materials.

[0048] In this embodiment, by adding a β-crystal nucleating agent, the toughness of polypropylene can be improved. This is because 1) the β-crystal nucleating agent has good compatibility with the polypropylene matrix and is uniformly distributed in the polypropylene; 2) the addition of the β-crystal nucleating agent significantly increases the relative content of β crystals, and the β crystals form a flower-like aggregate network structure, which can effectively absorb impact energy. On the other hand, the thermo-oxidative stability of polypropylene can be improved because the addition of the β-crystal nucleating agent significantly reduces the crystal size of polypropylene, inducing the formation of a large number of β crystals, thereby 1) reducing the mobility of molecular chains in crystalline and amorphous regions; 2) increasing the mechanical coupling between the β-crystal and amorphous regions; and 3) reducing the oxygen diffusion coefficient and solubility coefficient.

[0049] In this embodiment, the addition of lignin improves the strength and stiffness of polypropylene. This is because the combined use of lignin with talc, elastomer, and β-crystal nucleating agent, meeting the aforementioned mass percentage requirements, achieves a balance between stiffness and toughness in the polypropylene composite material. Furthermore, it enhances the stability of polypropylene due to: 1) the uniform distribution of lignin in the polypropylene melt; 2) the ability of polyphenols in lignin to capture free radicals and prevent the auto-oxidation cycle of polypropylene; 3) the effective absorption of ultraviolet light by the conjugated structure within the lignin molecule, preventing direct ultraviolet light from irradiating the polypropylene molecular chain and causing photodegradation; and 4) the carbonization of lignin at high temperatures, forming a protective layer on the outer layer of polypropylene, which reduces the oxygen diffusion rate and thus improves the polymer's antioxidant properties.

[0050] The embodiments of this application, through the addition of stabilizers, hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers, can significantly improve the thermo-oxidative stability of polypropylene. This is because the selected high-performance heat stabilizers possess excellent thermal stability, activity, migration, processability, and excellent compatibility with the polypropylene matrix. During cyclic processing and use, they can play a synergistic role, efficiently and continuously stabilizing free radicals (capturing free radicals and decomposing peroxides), preventing chain reactions, and thus delaying the aging and degradation process of polypropylene.

[0051] In a specific example, the lignin content

[0052] According to embodiments of this application, the components, by mass percentage, are:

[0053] Polypropylene: 60%–70%;

[0054] Talc: 10%–20%;

[0055] Elastomer: 5%–10%;

[0056] Lignin: 5%–10%;

[0057] Stabilizer: 0.5%–1%;

[0058] β-crystal nucleating agent: 0.03%–0.05%;

[0059] Other additives: 0.1%–3%.

[0060] This application embodiment further limits the dosage range of β-crystal nucleating agent, high-performance stabilizer and lignin. The combined use of β-crystal nucleating agent, high-performance stabilizer and lignin can better exert a high-efficiency synergistic effect, delay the aging and degradation process of polypropylene, slow down the decline of the mechanical properties of polypropylene materials, and improve the long-term service life of polypropylene materials.

[0061] According to the embodiments of this application, the mass ratio of hindered phenolic primary antioxidant, phosphite secondary antioxidant and hindered amine light stabilizer is 1:(1-6):(1-4).

[0062] In specific examples, the mass ratio of hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer is 1:1:1, 1:2:1, 1:3:1, 1:4:1, 1:5:1, 1:6:1, 1:1:2, 1:2:2, 1:3:2, 1:4:2, 1:5:2, 1:6:2, 1:1:3, 1:2:3, 1:3:3, 1:4:3, 1:5:3, 1:6:3, 1:1:4, 1:2:4, 1:3:4, 1:4:4, 1:5:4, 1:6:4, etc.

[0063] In this embodiment, the mass ratio of hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer satisfies the above conditions, which is beneficial for the hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer to better exert their synergistic effects and further improve the thermo-oxidative stability of polypropylene.

[0064] According to embodiments of this application, the mass ratio of hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer is 1:4:2.

[0065] In this embodiment, the mass ratio of hindered phenolic primary antioxidant, phosphite secondary antioxidant, and hindered amine light stabilizer is 1:4:2, which improves the thermo-oxidative stability of polypropylene while saving costs.

[0066] According to the embodiments of this application, the stabilizer satisfies at least one of the following (1) to (3):

[0067] (1) Hindered phenolic primary antioxidants include at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenylmethyl)benzene and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione;

[0068] (2) Hindered phenolic antioxidants include at least one of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite and bis(2,4-dicumylphenyl) pentaerythritol-diphosphite;

[0069] (3) Hindered amine light stabilizers include at least one of poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino]} and N,N”'-1,2-ethylenedimethyldi[N-[3-[[4,6-di[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl]amino]propyl]-N,N”-dibutyl-N,N”-di(1,2,2,6,6-pentamethyl-4-piperidinyl)-1,3,5-triazine-2,4,6-triamine].

[0070] Hindered phenols, the primary antioxidant, are used to capture free radicals, while phosphites, the secondary antioxidant, are used to decompose hydrogen peroxide. Hindered amines, the light stabilizer, inhibit the auto-oxidation cycle of polypropylene. By further limiting the selection of the above components, the synergistic effect is enhanced, the thermo-oxidative stability of polypropylene is improved, and the long-term service life of polypropylene materials is increased.

[0071] According to embodiments of this application, lignin includes sulfur-free lignin.

[0072] In this embodiment, sulfur-free lignin is selected, which helps to further reduce the adverse effects on hindered amine light stabilizers and improve the anti-aging effect of polypropylene.

[0073] According to embodiments of this application, the β-crystal nucleating agent includes at least one of the following seven:

[0074] Fused ring aromatic compounds;

[0075] Complexes composed of dicarboxylic acids and oxides of group IIA metals;

[0076] A complex composed of dicarboxylic acids and hydroxides of group IIA metals;

[0077] Complexes composed of dicarboxylic acids and group IIA metal salts;

[0078] Group IIA metal salts;

[0079] Aromatic amide compounds;

[0080] Rare earth compounds.

[0081] In the embodiments of this application, the β-crystal nucleating agent includes at least one of the above seven types, exhibiting a good nucleation effect, which is beneficial to improving the toughness and thermo-oxidative stability of polypropylene.

[0082] Furthermore, in the embodiments of this application, the β-crystal nucleating agent includes at least one of group IIA metal salts and aromatic amide compounds.

[0083] According to embodiments of this application, the β-crystal nucleating agent includes at least one of a carboxylic acid metal salt of tetrahydrophthalic anhydride and N,N′-dicyclohexylterephthalamide.

[0084] In the embodiments of this application, the β-crystal nucleating agent is selected from at least one of the carboxylic acid metal salt of tetrahydrophthalic anhydride and N,N′-dicyclohexyl terephthalamide, which exhibits good nucleation effect and compatibility with polypropylene, thus improving the toughness and thermo-oxidative stability of polypropylene.

[0085] According to the embodiments of this application, the components of the polypropylene composite material satisfy at least one of the following (1) to (4):

[0086] (1) Polypropylene includes at least one of homopolymer polypropylene, random copolymer polypropylene and impact copolymer polypropylene;

[0087] (2) The elastomer includes at least one of ethylene-octene copolymer and ethylene-butene copolymer;

[0088] (3) The talc powder has a mesh size of 1000-5000 mesh and a silica content of not less than 60%;

[0089] (4) Other additives include at least one of lubricants, plasticizers and processing aids.

[0090] In this embodiment, the polypropylene includes at least one of homopolymer polypropylene, random copolymer polypropylene, and impact copolymer polypropylene. Homopolymer polypropylene, random copolymer polypropylene, and impact copolymer polypropylene each have their own mechanical property characteristics, and the polypropylene material with the required mechanical properties can be selected based on the application scenario of the polypropylene composite material. Further, the polypropylene is polypropylene produced using a metallocene catalyst. Compared to polypropylene prepared using a metallocene catalyst, polypropylene prepared using a Zieglar-Natta catalyst has higher isotacticity and the isotactic propylene sequence is unevenly distributed on the molecular chain, resulting in poorer molecular chain stability. It is more likely to affect the low isotacticity molecular chains through "aging contagion," accelerating the oxidative degradation of polypropylene. Therefore, polypropylene prepared using a metallocene catalyst can be further selected as the matrix resin to improve the anti-aging properties of the composite material.

[0091] In the embodiments of this application, the elastomer may be selected as a copolymer of ethylene and octene, or a copolymer of ethylene and butene, or a combination of both.

[0092] In this embodiment, the talc powder mesh size meets the above conditions, which is beneficial for obtaining better mechanical properties and dispersibility, and also saves costs; the silica content of the talc powder meets the above requirements, which is beneficial for ensuring the purity of the talc powder and reducing the impact of impurities on the anti-aging properties of polypropylene. Further, the talc powder mesh size is 2000-3000 mesh.

[0093] In this embodiment, the combined action of polypropylene, elastomer, and talc helps to improve the mechanical properties of polypropylene.

[0094] A second aspect of this application provides a method for preparing a polypropylene composite material, comprising:

[0095] The raw materials polypropylene, talc, elastomer, lignin, stabilizer, β-crystal nucleating agent and other additives are mixed to obtain a mixture.

[0096] The mixture is melt-extruded, cooled, granulated, and dried to obtain a polypropylene composite material;

[0097] The raw material composition, by weight percentage, includes:

[0098] Polypropylene: 60%–70%;

[0099] Talc: 10%–20%;

[0100] Elastomer: 5%–10%;

[0101] Lignin: 1%–15%;

[0102] Stabilizer: 0.1%–1%;

[0103] β-crystal nucleating agent: 0.02%–0.1%;

[0104] Other additives: 0%–3%;

[0105] Stabilizers include hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers.

[0106] In specific examples, the lignin content is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc. The stabilizer content is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc. The β-crystal nucleating agent content is 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, etc.

[0107] In specific examples, the polypropylene content is 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, etc.; the talc content is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%; and the elastomer content is 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0108] The embodiments of this application utilize a combination of β-crystal nucleating agent, high-performance stabilizer, and lignin, ensuring that each component meets the aforementioned mass ratio, thereby achieving a highly efficient synergistic effect. This provides efficient and continuous stabilization of free radicals, delaying the aging and degradation process of polypropylene, mitigating the decline in the mechanical properties of polypropylene materials, and improving the long-term service life of polypropylene materials.

[0109] The embodiments of this application prepare polypropylene composite materials by melt extrusion molding, which is beneficial for industrial production.

[0110] According to embodiments of this application, a method for preparing a polypropylene composite material includes the following steps:

[0111] S1000: Polypropylene, talc, elastomer, lignin, stabilizer, β-crystal nucleating agent, and other additives are mixed together to obtain a mixture. In a specific example, the mixing process can be carried out using a high-speed mixer for 6 to 10 minutes until the mixture is homogeneous.

[0112] S2000: The above mixture is melt-extruded, cooled, granulated, and dried to obtain a polypropylene composite material resistant to performance degradation. In a specific example, the melt extrusion operation includes: adding the mixture into a twin-screw extruder through the feed port for melt extrusion. The processing temperatures of each section of the twin-screw extruder are as follows: feeding section: 160℃; compression section: 180℃; plasticizing section: 190℃; metering section: 200℃; mixing section: 210℃; die head: 210℃; pressure: 12MPa~18MPa; main screw speed: 500r / min~600r / min; and the screw combination is selected as weak shear and strong dispersion.

[0113] A third aspect of this application provides a vehicle component comprising the aforementioned polypropylene composite material, or comprising a polypropylene composite material prepared by the aforementioned method.

[0114] The vehicle components provided in this application embodiment include the aforementioned polypropylene composite material, which has high safety and a long service life.

[0115] According to embodiments of this application, vehicle components include, but are not limited to, bumpers, dashboards, door panels and pillar trims, fan blades, mudguards, front-end modules, engine hoods, gear shift box bases, rearview mirror brackets, seat covers, door covers, pillar covers, parcel shelf covers, rear bumper plates, fuel tanks, radiator water chambers, accelerator pedals, truck bumper brackets, etc.

[0116] The following will explain the solution of this application with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0117] Example 1

[0118] Add 12.8 kg of polypropylene-1#, 3 kg of talc, 2 kg of elastomer, 2 kg of lignin, 0.14 kg of high-performance stabilizer (1010:626:944 = 1:4:2), 0.02 kg of β-crystal nucleating agent NAB82, and 0.04 kg of other additives to a high-speed mixer and mix for 10 minutes until the mixture is uniform.

[0119] The uniformly mixed raw materials were then fed into a twin-screw extruder through the feed port for melt extrusion. The processing temperatures of each zone of the twin-screw extruder were as follows: Zone 1: 160℃, Zones 2-5: 180℃, Zones 6-9: 200℃, and the die head: 210℃; the pressure was 15 MPa, the main screw speed was 600 r / min, and the screw combination was selected as weak shear and strong dispersion. After melt extrusion, cooling, granulation, and drying, a polypropylene composite material 1 for automotive applications with resistance to performance degradation was obtained.

[0120] Example 2-12

[0121] The proportions of talc, elastomer, lignin, high-performance stabilizer, and β-crystal nucleating agent in Example 1 were changed according to the content (mass percentage) of each component in Examples 2-12 in Table 1. All raw materials were added together to a high-speed mixer and mixed for 10 minutes until uniform.

[0122] Then, the above-mentioned uniformly mixed raw materials are melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain automotive polypropylene composite material 2-polypropylene composite material 12 with resistance to performance degradation.

[0123] Example 13

[0124] Add 12.8 kg of polypropylene-2#, 0.3 kg of talc, 0.2 kg of elastomer, 0.2 kg of lignin, 0.014 kg of high-performance stabilizer (1790:686:944 = 1:4:2), 0.002 kg of β-crystal nucleating agent NAB82, and 0.004 kg of other additives to a high-speed mixer and mix for 10 minutes until uniform.

[0125] Then, the above-mentioned uniformly mixed raw materials are melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain automotive polypropylene composite material 13 with resistance to performance degradation.

[0126] Examples 14-24

[0127] The proportions of talc, elastomer, lignin, high-performance stabilizer, and β-crystal nucleating agent in Example 13 were changed according to the content (mass percentage) of each component in Examples 14-24 in Table 1. All raw materials were added together to a high-speed mixer and mixed for 10 minutes until uniform.

[0128] Then, the above-mentioned uniformly mixed raw materials are melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain automotive polypropylene composite material 14-polypropylene composite material 24 with resistance to performance degradation.

[0129] Example 25

[0130] Add 12.8 kg of polypropylene-3#, 0.3 kg of talc, 0.2 kg of elastomer, 0.2 kg of lignin, 0.014 kg of high-performance stabilizer (1330:626:119 = 1:4:2), 0.002 kg of β-crystal nucleating agent NAB82, and 0.004 kg of other additives to a high-speed mixer and mix for 10 minutes until the mixture is uniform.

[0131] Then, the above-mentioned uniformly mixed raw materials are melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain automotive polypropylene composite material 13 with resistance to performance degradation.

[0132] Examples 26-36

[0133] The proportions of talc, elastomer, lignin, high-performance stabilizer, and β-crystal nucleating agent in Example 25 were changed according to the content (mass percentage) of each major component in Examples 14-24 in Table 1. All raw materials were added together to a high-speed mixer and mixed for 10 minutes until uniform.

[0134] Then, the above-mentioned uniformly mixed raw materials are melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain automotive polypropylene composite material 14-polypropylene composite material 24 with resistance to performance degradation.

[0135] Comparative Examples 1-5

[0136] Add 12.8 kg of polypropylene-1# along with a certain proportion of talc, elastomer, lignin, high-performance stabilizer, β-crystal nucleating agent and other additives (the content of each component (mass percentage) is as shown in Table 2) to a high-speed mixer and mix for 10 minutes until the mixture is uniform.

[0137] Then, the above-mentioned uniformly mixed raw materials are subjected to melt extrusion, cooling, granulation and drying treatment (processing technology and process parameters are the same as in Example 1) to obtain comparative polypropylene composite material 1-polypropylene composite material 5.

[0138] Comparative Examples 6-10

[0139] Add 12.8 kg of polypropylene-1# along with a certain proportion of talc, elastomer, lignin, high-performance stabilizer, β-crystal nucleating agent and other additives (the content of each component (mass percentage) is as shown in Table 2) to a high-speed mixer and mix for 10 minutes until the mixture is uniform.

[0140] Then, the above-mentioned uniformly mixed raw materials were melt-extruded, cooled, granulated, and dried (the processing technology and process parameters are the same as in Example 1) to obtain comparative polypropylene composite material 6-polypropylene composite material 10.

[0141] Comparative Examples 11-15

[0142] Add 12.8 kg of polypropylene-1# along with a certain proportion of talc, elastomer, lignin, high-performance stabilizer, β-crystal nucleating agent and other additives (the content of each component (mass percentage) is as shown in Table 2) to a high-speed mixer and mix for 10 minutes until the mixture is uniform.

[0143] Then, the above-mentioned uniformly mixed raw materials are subjected to melt extrusion, cooling, granulation and drying treatment (processing technology and process parameters are the same as in Example 1) to obtain comparative polypropylene composite material 11-polypropylene composite material 15.

[0144] Table 1. Content of each component in the examples (mass percentage)

[0145]

[0146] Table 2. Content of each component in the comparative example (mass percentage)

[0147]

[0148] Note: In the examples and comparative examples, polypropylene-1# represents homopolymer polypropylene, polypropylene-2# represents random copolymer polypropylene, and polypropylene-3# represents impact copolymer polypropylene; the elastomer is a copolymer of ethylene and octene; other additives are lubricant carbon black.

[0149] Performance testing

[0150] I. Performance Testing Methods.

[0151] 1. Melt flow rate (MFR, g / 10min): Refer to GB / T 3682.1-2018.

[0152] 2. Mechanical properties, including tensile strength (MPa), flexural modulus (MPa), and notched impact strength (KJ / m). 2 (Refer to GB / T 1040-92 and GB / T 1043-93; The conditioning and testing environment for plastic specimens shall be in accordance with GB / T2918-1998, at (23±2)℃ and (50±5)% relative humidity, with a conditioning time of 48h.)

[0153] 3. Oven thermal aging failure time (h): Referring to ISO 4577-1983 and ASTM D 3079-79, polypropylene samples were placed in a 150℃ thermal aging test chamber. The appearance of the samples was checked hourly for the first 5 hours, every 8 to 16 hours for the first 360 hours, and daily after 360 hours. The time at which the samples began to fail was recorded, and the average value of 5 samples was calculated. This standard was used to evaluate the long-term thermo-oxidative stability of polypropylene composites.

[0154] 4. Outdoor Exposure Test Specimen Failure Time (d): Following GB / T 3681-83 standard, polypropylene specimens were mounted in fixtures directly attached to a specimen holder. The specimen holder was located on the rooftop, facing south at a 23° angle to the horizontal. The specimens were inspected weekly for changes in appearance. The specimens were folded 180°, and the time to brittle fracture at the point where the specimens were not in contact with the wooden strip was used as the evaluation index. Five specimens were taken, and the average value was calculated. This standard was used to evaluate the natural aging performance of polypropylene composites.

[0155] 5. Processing performance: Outdoor exposed samples were taken periodically, and the melt flow rate was tested according to GB / T 3682.1-2018 to evaluate the processing performance of polypropylene composites.

[0156] 6. Long-term performance: Outdoor exposed samples were taken periodically and their mechanical properties were tested according to GB / T 1040-92 and GB / T 1043-93 standards to evaluate the long-term performance of polypropylene composite materials.

[0157] II. Performance Test Results.

[0158] 1. Test results of melt flow rate.

[0159] The test results of the melt flow rate of the polypropylene composite materials provided in the examples and comparative examples are shown in Tables 3 and 4.

[0160] Table 3 shows the trend of melt flow rate of the polypropylene composite material provided in the examples.

[0161]

[0162] Table 4 shows the trend of melt flow rate of the polypropylene composite material provided in the comparative examples.

[0163]

[0164] Note: In Tables 3 and 4, " / " indicates that the melt flow rate is too high to be measured.

[0165] As shown in Tables 3 and 4, at day 0, the melt flow rates of the example samples were all lower than those of the corresponding comparative samples. This indicates that the molecular weight of the example samples was lower, and the degree of aging degradation of polypropylene was less. With increasing exposure time, the melt flow rate gradually increased, but the increase in melt flow rate of the example samples was less than that of the corresponding comparative samples. When the example samples were exposed outdoors for 60–120 days, the melt flow rate was too high to measure. In contrast, the melt flow rate of the comparative samples was too high to measure after only 0–30 days of outdoor exposure. Therefore, adding appropriate amounts of β-crystal nucleating agents, high-performance stabilizers, and lignin to polypropylene materials can slow down the decrease in molecular weight of polypropylene materials and improve their anti-aging properties.

[0166] 2. Test results of outdoor exposed specimen failure time and oven-aged specimen failure time

[0167] The test results of the melt flow rate of the polypropylene composite materials provided in the examples and comparative examples are shown in Tables 5 and 6.

[0168] Table 5 shows the test results of the failure time of the polypropylene composite material oven-aged specimens and the failure time of the outdoor-exposed specimens provided in the examples.

[0169]

[0170] Table 6 shows the test results of the failure time of the polypropylene composite material oven-aged specimens and the failure time of the outdoor-exposed specimens provided in the comparative examples.

[0171]

[0172] As shown in Tables 5 and 6, compared with Comparative Examples 2-5, Examples 1-12 showed an increase in the degradation time of oven-aged samples by 32-1104 hours, and the degradation time of outdoor-exposed samples by 5-356 days. Examples 13-24 showed an increase in the degradation time of oven-aged samples by 272-1392 hours, and the degradation time of outdoor-exposed samples by 106-420 days. Examples 25-36 showed an increase in the degradation time of oven-aged samples by 872-1376 hours, and the degradation time of outdoor-exposed samples by 307-441 days. Therefore, it can be seen that the embodiments of this application, by using a combination of high-performance stabilizers, β-crystal nucleating agents, and lignin, effectively delayed the aging degradation and performance decline process of polypropylene materials.

[0173] 3. Test results of the trend of mechanical property changes.

[0174] The test results of the melt flow rate of the polypropylene composite materials provided in the examples and comparative examples are shown in Tables 7 and 8.

[0175] Table 7 shows the trend of mechanical properties of the polypropylene composite materials provided in the examples.

[0176]

[0177] Table 8. Trends in the mechanical properties of comparative polypropylene composite materials

[0178]

[0179] Note: " / " indicates that the mechanical properties of the material cannot be measured.

[0180] The test results in Table 7 show that:

[0181] The automotive polypropylene materials prepared in Examples 1-12 exhibited initial tensile strengths of 37.4 MPa to 47.2 MPa, initial flexural modulus of 2640 MPa to 3519 MPa, and initial notched impact strength of 3.4 KJ / m. 2 ~5.6KJ / m 2 After 360 days of outdoor exposure, the tensile strength decay rate was 16.1%–18.6%, the flexural modulus decay rate was 16.1%–17.3%, and the notched impact strength decay rate was 18.0%–19.0%.

[0182] The automotive polypropylene materials prepared in Examples 13-24 exhibited initial tensile strengths of 28.0 MPa to 35.1 MPa, initial flexural modulus of 1981 MPa to 2854 MPa, and initial notched impact strength of 6.4 KJ / m². 2 ~9.1KJ / m2 After 360 days of outdoor exposure, the tensile strength decay rate was 15.4%–16.6%, the flexural modulus decay rate was 15.4%–16.6%, and the notched impact strength decay rate was 16.9%–18.0%.

[0183] The automotive polypropylene materials prepared in Examples 25-36 exhibited resistance to performance degradation, with initial tensile strengths ranging from 24.1 MPa to 28.2 MPa, initial flexural modulus ranging from 992 MPa to 2156 MPa, and initial notched impact strength of 42.3 KJ / m. 2 ~69.4KJ / m 2 After 360 days of outdoor exposure, the tensile strength decay rate was 13.9%–26.1%, the flexural modulus decay rate was 14.0%–15.4%, and the notched impact strength decay rate was 14.9%–16.4%.

[0184] As can be seen from the test data in Tables 7 and 8, the initial tensile strength of the polypropylene materials prepared in Comparative Examples 1-5 ranges from 28.3 MPa to 41.2 MPa, the initial flexural modulus from 1907 MPa to 2804 MPa, and the initial notched impact strength is 2.0 KJ / m. 2 ~4.2KJ / m 2 After 360 days of outdoor exposure, compared with Comparative Examples 1-5, the tensile strength attenuation rate of Examples 1-12 of this application decreased by 8.69% to 20.91%, the flexural modulus attenuation rate decreased by 9.02% to 22.68%, and the notched impact strength attenuation rate decreased by 7.67% to 19.1%. The polypropylene materials prepared in Comparative Examples 6-10 had an initial tensile strength of 19.5 MPa to 30.2 MPa, an initial flexural modulus of 1302 MPa to 1963 MPa, and an initial notched impact strength of 3.1 KJ / m. 2 ~7.3KJ / m 2 After 360 days of outdoor exposure, compared with Comparative Examples 6-10, Examples 13-24 of this application showed a decrease in tensile strength attenuation rate of 9.81% to 20.33%, a decrease in flexural modulus attenuation rate of 9.57% to 27.6%, and a decrease in notched impact strength attenuation rate of 8.85% to 20.72%. The polypropylene materials prepared in Comparative Examples 11-15 had an initial tensile strength of 13.6 MPa to 23.1 MPa, an initial flexural modulus of 1001 MPa to 1423 MPa, and an initial notched impact strength of 20.4 KJ / m. 2 ~49.2KJ / m 2After 360 days of outdoor exposure, compared with Comparative Examples 11-15, Examples 25-36 of this application showed a decrease in tensile strength attenuation rate of 1.51% to 17.72%, a decrease in flexural modulus attenuation rate of 12.42% to 29.0%, and a decrease in notched impact strength attenuation rate of 11.63% to 21.84%. The comparison between the examples and comparative examples shows that adding β-crystal nucleating agents, high-performance stabilizers, and lignin to polypropylene materials can effectively improve the mechanical properties of polypropylene materials, extend the aging time of polypropylene materials, and reduce the magnitude of mechanical property attenuation, enabling polypropylene materials to retain certain mechanical properties after 360 days of outdoor exposure.

[0185] In summary, this invention, by compounding metallocene polypropylene resin with talc, lignin, β-crystal nucleating agent, and elastomer in a certain proportion, ensures a balance between rigidity and toughness in polypropylene products. The added β-crystal nucleating agent improves the toughness and thermo-oxidative stability of the polypropylene material. The added high-performance stabilizer possesses excellent thermal stability, activity, migration, processability, and excellent compatibility with the polypropylene matrix, significantly improving the thermo-oxidative stability of polypropylene. The added lignin, β-crystal nucleating agent, and high-performance stabilizer can exert a highly efficient synergistic effect, effectively and continuously stabilizing free radicals, delaying the aging and degradation process of polypropylene, slowing down the decline in the mechanical properties of polypropylene materials, and improving the long-term service life of polypropylene materials. This invention successfully prepares a performance-resistant automotive polypropylene composite material.

[0186] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A polypropylene composite material, characterized in that, Components included, by mass percentage: Polypropylene: 60%~70%; Talc: 10%~20%; Elastomer: 5%~10%; Lignin: 1%~15%; Stabilizer: 0.1%~1%; β-crystal nucleating agent: 0.02%~0.1%; Other additives: 0%~3%; The stabilizers include hindered phenolic primary antioxidants, phosphite secondary antioxidants, and hindered amine light stabilizers; The β-crystal nucleating agent includes at least one of a carboxylic acid metal salt of tetrahydrophthalic anhydride and N,N'-dicyclohexyl terephthalamide; The mass ratio of the hindered phenolic primary antioxidant, the phosphite secondary antioxidant, and the hindered amine light stabilizer is 1:(1~6):(1~4); The stabilizer satisfies the following (1) to (3): (1) The hindered phenolic main antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenylmethyl)benzene and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione; (2) The hindered phenolic antioxidant includes at least one of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite and bis(2,4-dicumylphenyl) pentaerythritol diphosphite; (3) The hindered amine light stabilizer includes at least one of poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino]} and N,N'''-1,2-ethylenedimethyldi[N-[3-[[4,6-di[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl]amino]propyl]-N,N''-dibutyl-N,N''-di(1,2,2,6,6-pentamethyl-4-piperidinyl)-1,3,5-triazine-2,4,6-triamine].

2. The polypropylene composite material according to claim 1, characterized in that, Components included, by mass percentage: Polypropylene: 60%~70%; Talc: 10%~20%; Elastomer: 5%~10%; Lignin: 5%~10%; Stabilizer: 0.5%~1%; β-crystal nucleating agent: 0.03%~0.05%; Other additives: 0.1%~3%.

3. The polypropylene composite material according to claim 1, characterized in that, The mass ratio of the hindered phenolic primary antioxidant, the phosphite secondary antioxidant, and the hindered amine light stabilizer is 1:4:

2.

4. The polypropylene composite material according to any one of claims 1 to 3, characterized in that, The lignin includes sulfur-free lignin.

5. The polypropylene composite material according to any one of claims 1 to 3, characterized in that, The component satisfies at least one of the following (1) to (4): (1) The polypropylene includes at least one of homopolymer polypropylene, random copolymer polypropylene and impact copolymer polypropylene; (2) The elastomer includes at least one of ethylene-octene copolymer and ethylene-butene copolymer; (3) The talc powder has a mesh size of 1000-5000 mesh and a silica content of not less than 60%; (4) The other additives include at least one of lubricant and plasticizer.

6. A method for preparing the polypropylene composite material according to any one of claims 1 to 5, characterized in that, include: The raw materials polypropylene, talc, elastomer, lignin, stabilizer, β-crystal nucleating agent and other additives are mixed to obtain a mixture. The mixture is melt-extruded, cooled, granulated, and dried to obtain a polypropylene composite material.

7. A vehicle component, characterized in that, The composite material comprises the polypropylene composite material according to any one of claims 1 to 5, or the polypropylene composite material obtained by the preparation method according to claim 6.

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