Polypropylene composite material, and preparation method and application thereof

Abstract

The application discloses a kind of polypropylene composite material and preparation method and application thereof, belong to high polymer material technical field, including the following weight parts of component: including the following weight parts of component: 100 polypropylene resin, 14~32 parts of acrylate monomer, 0.14~0.32 parts of chain transfer agent, 0.14~0.32 parts of initiator, 0.9~11 parts of 3-methacryl dopamine-maleic anhydride copolymer, 0.04~0.32 parts of nucleating agent;The mass percentage content of 3-methacryl dopamine in the 3-methacryl dopamine-maleic anhydride copolymer is 5~25%.The polypropylene composite material has excellent coating adhesion and aging resistance, and the polypropylene composite material is very suitable for preparing automobile parts, especially for preparing automobile bumpers.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Compared to other general-purpose thermoplastics, polypropylene (PP) exhibits excellent mechanical properties while offering advantages such as low density, low price, simple synthesis, and chemical resistance. This has led to rapid development of PP in the automotive, home appliance, medical, and construction sectors, and it has gradually become the fastest-growing plastic in terms of production volume. With the increasing global awareness of environmental protection and calls for sustainable development, research on the recycling of PP materials has become a research hotspot in recent years. Currently, within the field of PCR (Post-Consumer Recycled) materials, PP is the primary recycled material in the PCR field due to its ability to retain its advantages to the greatest extent possible after recycling. Based on a 10kg bicycle bumper, the potential reserves exceed 20,000 tons, demonstrating the enormous potential and commercial value of PCR-based PP materials in the automotive industry.

[0003] Although PP is the most cost-effective material for automotive exterior trim, as a non-polar crystalline material, it has poor surface adhesion and wettability. Therefore, without surface pretreatment, it is difficult to spray-coat water-based paint on it. This severely restricts the large-scale application of PP in automotive exterior trim. Currently, methods for improving the surface adhesion of polypropylene include flame treatment, corona treatment, and chemical oxidation. The current technical difficulty lies in achieving a uniform surface treatment effect while avoiding excessive treatment, which would affect the material's performance. Therefore, improving the coating adhesion of polypropylene has become a technical problem that needs to be solved urgently by those skilled in the art.

[0004] In view of this, this application is filed. Summary of the Invention

[0005] The object of the present invention is to overcome the shortcomings of the prior art and provide a polypropylene composite material and its preparation method and application. The polypropylene composite material has excellent coating adhesion and aging resistance. The polypropylene composite material is very suitable for preparing automotive parts, especially for preparing automotive bumpers.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A polypropylene composite material comprises the following components in parts by weight: 100 parts of polypropylene resin, 14 to 32 parts of acrylate monomer, 0.14 to 0.32 parts of chain transfer agent, 0.14 to 0.32 parts of initiator, 0.9 to 11 parts of 3-methacryloyldopamine-maleic anhydride copolymer, and 0.04 to 0.32 parts of nucleating agent;

[0008] The mass percentage of 3-methacryloyldopamine in the 3-methacryloyldopamine-maleic anhydride copolymer is 5-25%, for example, it can be 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25% or a range consisting of any two values ​​therein.

[0009] The present invention creatively prepares a composite material by combining the above raw materials, taking polypropylene resin as a matrix, and effectively improving the coating adhesion and aging resistance of the polypropylene composite material under the joint action of an acrylate monomer, a chain transfer agent, an initiator, a 3-methacryloyldopamine-maleic anhydride copolymer, and a nucleating agent. The polypropylene composite material is very suitable for preparing automotive parts, especially for preparing automotive bumpers.

[0010] The present invention uses polypropylene resin as a matrix. By adding acrylate monomers, chain transfer agents, and initiators, a surface-initiated hydrogen atom transfer reversible addition-fragmentation chain transfer method can be used to synthesize high-density polymer brushes on the polypropylene resin surface. Under mild conditions, the graft polymerization of various polar monomers, such as acrylates, can be directly initiated from the C-H bonds on the PP surface. Unlike the introduction of polar components, the polar polymer groups grafted onto the PP surface in this way can fundamentally increase the polarity of the PP material. Furthermore, because this modified grafting method is a controllable active polymerization, the thickness of the polymer brush layer and the surface polymer graft density can be effectively controlled by optimizing the acrylate monomer content in the reaction. This improves the polarity of the PP surface while effectively enhancing aging resistance. By adding a nucleating agent and a 3-methacryloyldopamine-maleic anhydride copolymer, the nucleation sites on the surface of the nucleating agent are utilized to induce efficient crystallization of the PP material, resulting in not only high paint film adhesion but also excellent aging resistance. At the same time, 3-methacryloyldopamine-maleic anhydride copolymer is introduced into the matrix to reduce the surface polarity of the PP composite material while realizing the design of the bionic microphase network structure. The multiple interactions between the substrate and the water-based primer on the interface are utilized to improve the adhesion and aging resistance of the polypropylene composite material from multiple aspects.

[0011] The amount of the acrylate monomer is 14 to 32 parts, for example, 14 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts or a range consisting of any two of these values.

[0012] Preferably, the amount of the acrylate monomer is 15 to 30 parts.

[0013] The amount of the chain transfer agent is 0.14 to 0.32 parts, for example, 0.14 parts, 0.15 parts, 0.18 parts, 0.2 parts, 0.22 parts, 0.25 parts, 0.28 parts, 0.3 parts, 0.32 parts or a range consisting of any two of these values.

[0014] Preferably, the amount of the chain transfer agent is 0.15 to 0.3 parts.

[0015] The amount of the initiator is 0.14 to 0.32 parts, for example, 0.14 parts, 0.15 parts, 0.18 parts, 0.2 parts, 0.22 parts, 0.25 parts, 0.28 parts, 0.3 parts, 0.32 parts or a range consisting of any two of these values.

[0016] Preferably, the amount of the initiator is 0.15 to 0.3 parts.

[0017] The amount of the 3-methacryloyldopamine-maleic anhydride copolymer is 0.9 to 11 parts, for example, 0.9 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or a range consisting of any two of these values.

[0018] Preferably, the amount of the 3-methacryloyldopamine-maleic anhydride copolymer is 1 to 10 parts.

[0019] The amount of the nucleating agent is 0.04 to 0.32 parts, for example, 0.04 parts, 0.05 parts, 0.08 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.32 parts or a range consisting of any two of these values.

[0020] Preferably, the amount of the nucleating agent is 0.05 to 0.3 parts.

[0021] Preferably, the polypropylene composite material comprises the following components in parts by weight: 100 parts of polypropylene resin, 15 to 30 parts of acrylate monomer, 0.15 to 0.3 parts of chain transfer agent, 0.15 to 0.3 parts of initiator, 1 to 10 parts of 3-methacryloyldopamine-maleic anhydride copolymer, and 0.05 to 0.3 parts of nucleating agent.

[0022] Preferably, the polypropylene composite material comprises the following components in parts by weight: 100 parts of polypropylene resin, 20-25 parts of acrylate monomer, 0.2-0.25 parts of chain transfer agent, 0.2-0.25 parts of initiator, 5-8 parts of 3-methacryloyldopamine-maleic anhydride copolymer, and 0.15-0.25 parts of nucleating agent.

[0023] In the polypropylene composite material of the present application, the weight percentage of the polypropylene resin is not less than 70%.

[0024] Preferably, in the polypropylene composite material of the present application, the weight percentage of the polypropylene resin is 70-90%, for example, it can be 70%, 71%, 72%, 75%, 76%, 78%, 80%, 82%, 85%, 86%, 88%, 90% or a range consisting of any two of the above values.

[0025] Preferably, in the polypropylene composite material of the present application, the weight percentage of the polypropylene resin is 71-86%.

[0026] Preferably, the mass percentage of 3-methacryl dopamine in the 3-methacryl dopamine-maleic anhydride copolymer is 10-20%.

[0027] In the present application, the preparation method of 3-methacryl dopamine-maleic anhydride copolymer is not limited, and those skilled in the art can prepare 3-methacryl dopamine-maleic anhydride copolymer from 3-methacryl dopamine and maleic anhydride according to conventional methods.

[0028] For example, 3-methacryl dopamine and maleic anhydride copolymer are reacted in the presence of an initiator and a solvent at 65-75°C for 8-15h to obtain 3-methacryl dopamine-maleic anhydride copolymer.

[0029] The initiator includes azobisisobutyronitrile, potassium persulfate, ammonium persulfate and other common thermal initiators.

[0030] The solvent includes methanol, tetrahydrofuran, N-N'-dimethylformamide and other common organic solvents.

[0031] It should be noted that the 3-methacryl dopamine mentioned in the present application can be purchased from a conventional market, or can be obtained by reacting dopamine with methacryloyl chloride.

[0032] Exemplarily, the preparation method of 3-methacryloyl dopamine is: dopamine and methacryloyl chloride are reacted in a molar ratio of 1: (1.1 to 1.3) to graft a carbon-carbon unsaturated double bond to obtain 3-methacryloyl dopamine. The specific method is as follows: 10.0g of dopamine is dissolved in 100mL of methanol solution, and 7.2g of triethylamine is added to the solution to promote the dissolution of dopamine. After the system is dispersed into a light red solution, a proportional amount of methacryloyl chloride is added in an ice bath under nitrogen protection. While adding methacryloyl chloride, 20mL of 3.59mol / L triethylamine methanol solution is added as an acid binder to promote the reaction to move in the positive direction. The entire dropwise addition process lasts for about 1 hour, and the solution is transferred to a round-bottom flask after the white mist in the system disappears. Methanol was removed from the system by vacuum rotary evaporation. The residual solution was dissolved with 100 mL of ethyl acetate and transferred to a separatory funnel. The solution was extracted at least three times with 1 mol / L hydrochloric acid and 1 mol / L NaCl solution to remove triethylamine hydrochloride generated during the reaction. The organic phase obtained after extraction was then treated with anhydrous Na2SO4 to remove moisture. Finally, a white powdery solid was obtained by filtration and vacuum rotary evaporation. The crude product was dried and then quickly rinsed with ethyl acetate to remove black impurities on the surface. After drying, 3-methacryloyldopamine was obtained.

[0033] Preferably, the melt flow rate of the polypropylene resin at 230°C / 2.16kg is 10 to 40 g / 10min, for example, 10 g / 10min, 12 g / 10min, 15 g / 10min, 18 g / 10min, 20 g / 10min, 25 g / 10min, 30 g / 10min, 32 g / 10min, 35 g / 10min, 40 g / 10min or a range consisting of any two values ​​therein, and the test method is ISO1133-2011.

[0034] It should be noted that the present invention is not limited to the source of the polypropylene resin, which can be recycled polypropylene or new material.

[0035] Preferably, the polypropylene is recycled polypropylene, which is derived from at least one of washing machine barrel materials, ton bag materials, and daily miscellaneous materials. The use of recycled polypropylene can realize waste utilization and turn waste into treasure, and the recycled raw materials are easy to obtain and low in cost.

[0036] Preferably, the polypropylene resin has a melt flow rate of 20-32 g / 10 min at 230℃ / 2.16 kg, especially the polypropylene resin with this melt index has better compatibility of each raw material in the system, which can better promote the formation of reversible addition-fragmentation chain transfer, promote the formation of biomimetic microphase network structure, improve the processability, and further improve the adhesion and aging resistance of the polypropylene composite material.

[0037] Preferably, the acrylate monomer includes at least one of n-butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, butyl methacrylate, methyl methacrylate, methyl acrylate, hydroxypropyl methacrylate, and hydroxypropyl acrylate.

[0038] Preferably, the chain transfer agent includes at least one of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, 4-cyano-4-(dodecylsulfanylthiocarbonyl) sulfanylvaleric acid, and 2-cyanomethyl-N-methyl-N-phenyl dithiocarbamic acid.

[0039] Preferably, the initiator includes a benzophenone initiator; the benzophenone initiator includes at least one of Michler's ketone, benzophenone, 2-hydroxybenzophenone, 4-hydroxybenzophenone, 2,2'-dihydroxybenzophenone, 4-hydroxy-2'methyl carbonate benzophenone, diphenyloxybenzophenone, 4-methylbenzophenone, or 2,4,6-trimethylbenzophenone.

[0040] Preferably, the nucleating agent includes at least one of an alpha crystal nucleating agent, a beta crystal nucleating agent.

[0041] Preferably, the alpha crystal nucleating agent includes at least one of an organic phosphate alpha crystal nucleating agent, an organic carboxylate alpha crystal nucleating agent, and a sorbitol alpha crystal nucleating agent.

[0042] Preferably, the beta crystal nucleating agent includes at least one of an aromatic amide beta crystal nucleating agent and an organic carboxylic acid beta nucleating agent.

[0043] Preferably, the polypropylene composite material of the present application can further include at least one of an antioxidant, a mineral powder, a lubricant, a colorant, a weathering agent, an antistatic agent, a flame retardant, and a ultraviolet light absorber.

[0044] The polypropylene composite material of the present application can include an antioxidant, and suitable antioxidants include, but are not limited to, antioxidant 1098, antioxidant 1010, antioxidant 1076, antioxidant 168, and combinations thereof.

[0045] The polypropylene composite material of the present application can include a mineral powder, and suitable mineral powders include, but are not limited to, calcium carbonate, mica, kaolin, magnesium hydroxide, boehmite, and combinations thereof.

[0046] The polypropylene composite material according to the present application can comprise a colorant, and suitable colorants include, but are not limited to, carbon black, titanium white, zinc sulfide, iron red, titanium yellow, and combinations thereof.

[0047] The polypropylene composite material according to the present application can comprise a lubricant, and suitable lubricants include, but are not limited to, polyethylene wax, fatty acid ester, hyperbranched amide, and combinations thereof.

[0048] The polypropylene composite material according to the present application can comprise a weathering agent, and suitable weathering agents include, but are not limited to, hindered amine light stabilizers.

[0049] The polypropylene composite material according to the present application can comprise an antistatic agent, and suitable antistatic agents include, but are not limited to, zinc oxide, manganese dioxide, chromium trioxide, and combinations thereof.

[0050] The polypropylene composite material according to the present application can comprise a flame retardant, and suitable flame retardants include, but are not limited to, brominated polymers (e.g., brominated polystyrene), metal dialkyl phosphites (e.g., aluminum tris(diethyl phosphite)), metal hydroxides (e.g., magnesium hydroxide), aromatic phosphates (e.g., resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate)), and combinations thereof.

[0051] The polypropylene composite material according to the present application can comprise an ultraviolet light absorber, and suitable ultraviolet light absorbers include, but are not limited to, hydroxybenzophenones, benzotriazoles, hydroxybenzotriazines, cyanoacrylates, nanoscale inorganic materials (e.g., titanium oxide, cerium oxide, and zinc oxide), and combinations thereof.

[0052] The present application also provides a method for preparing the polypropylene composite material, comprising the following steps:

[0053] According to the ratio, the polypropylene resin, the 3-methylacryl dopamine-maleic anhydride copolymer, and the nucleating agent are uniformly mixed, and then are put into a double-screw extruder for melt extrusion, granulation, to obtain a master batch. The master batch, the acrylate monomer, the photoreaction agent, and the chain transfer agent are uniformly mixed, and then are put into a double-screw extruder for melt extrusion, granulation, to obtain the polypropylene composite material.

[0054] The present application also provides an application of the polypropylene composite material in preparing automobile parts. The polypropylene composite material according to the present application has excellent coating adhesion and aging resistance, and is very suitable for preparing automobile parts, especially for preparing automobile bumpers.

[0055] The present application also provides a bumper prepared from the polypropylene composite material.

[0056] The present invention also provides a paint spraying component, which is prepared using the above-mentioned polypropylene composite material.

[0057] The present invention has the following beneficial effects: Using polypropylene resin as a matrix, the invention incorporates acrylate monomers, a chain transfer agent, and an initiator, and utilizes a surface-initiated hydrogen atom transfer reversible addition-fragmentation chain transfer method to synthesize high-density polymer brushes on the polypropylene resin surface. Under mild conditions, the grafting polymerization of various polar monomers, such as acrylates, can be directly initiated from the C-H bonds on the PP surface. Unlike the introduction of polar components, the polar polymer groups grafted onto the PP surface in this manner can substantially increase the polarity of the PP material. Furthermore, because this modified grafting method is a controllable living polymerization, the thickness of the polymer brush layer and the surface polymer graft density can be effectively controlled by optimizing the acrylate monomer content in the reaction. This improves the surface polarity of the PP while effectively enhancing aging resistance. By adding a nucleating agent and a 3-methacryloyldopamine-maleic anhydride copolymer, the nucleation sites on the nucleating agent surface are utilized to induce efficient crystallization of the PP material, resulting in both high paint film adhesion and excellent aging resistance. At the same time, 3-methacryloyldopamine-maleic anhydride copolymer is introduced into the matrix to reduce the surface polarity of the PP composite material while realizing the design of the bionic microphase network structure. The multiple interactions between the substrate and the water-based primer on the interface are utilized to improve the adhesion and aging resistance of the polypropylene composite material from multiple aspects. DETAILED DESCRIPTION

[0058] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0059] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0060] In this application, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0061] The raw materials used in the embodiments and comparative examples are described as follows:

[0062] Polypropylene resin-1: recycled polypropylene, the base material is ton bag material, and the melt flow rate measured at 230℃ / 2.16kg is 20g / 10min.

[0063] Polypropylene resin-2: recycled polypropylene, the base material is daily miscellaneous materials, and the melt flow rate measured at 230℃ / 2.16kg is 32g / 10min.

[0064] Polypropylene resin-3: recycled polypropylene, the base material is ton bag material, and the melt flow rate measured at 230℃ / 2.16kg is 10g / 10min.

[0065] Polypropylene resin-4: recycled polypropylene, the base material is washing machine barrel material, and the melt flow rate measured at 230℃ / 2.16kg is 40g / 10min.

[0066] Polypropylene resin-5: melt flow rate measured at 230°C / 2.16 kg is 20 g / 10 min, Basel, EP548R.

[0067] Acrylate monomer-1: n-butyl acrylate, commercially available.

[0068] Acrylate monomer-2: hydroxyethyl acrylate, commercially available.

[0069] Acrylate monomer-3: hydroxyethyl methacrylate, commercially available.

[0070] Chain transfer agent-1: 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, commercially available.

[0071] Chain transfer agent-2: 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanylpentanoic acid, commercially available.

[0072] Chain transfer agent-3: 2-cyanomethyl-N-methyl-N-phenyldithiocarbamic acid, commercially available.

[0073] Initiator-1: Michler's ketone, commercially available.

[0074] Initiator-2: hydroxybenzophenone, commercially available.

[0075] Initiator-3: 4,4'-dimethoxybenzophenone, commercially available.

[0076] Nucleating agent-1: sorbitol-based α-crystal nucleating agent, bis(4-propylbenzylidene)propyl sorbitol, commercially available.

[0077] Nucleating agent-2: organic phosphate α crystal nucleating agent, di[2,2'-methylenebis(4,6-di-tert-butylphenyl) phosphate] hydroxy aluminum salt, Shanxi Chemical Research Institute, brand TMP-5.

[0078] Nucleating agent-3: aromatic amide β crystal nucleating agent, n,n'-dicyclohexyl-2,6-naphthalene dicarboxamide, commercially available.

[0079] 3-methacryloyl dopamine-maleic anhydride copolymer-1: the mass percentage content of dopamine is 10%.

[0080] 3-methacryloyl dopamine-maleic anhydride copolymer-2: the mass percentage content of dopamine is 20%.

[0081] 3-methacryloyl dopamine-maleic anhydride copolymer-3: the mass percentage content of dopamine is 5%.

[0082] 3-methacryloyl dopamine-maleic anhydride copolymer-4: the mass percentage content of dopamine is 25%.

[0083] 3-methacryloyl dopamine: commercially available.

[0084] Maleic anhydride: commercially available.

[0085] The preparation method of 3-methacryloyl dopamine-maleic anhydride copolymer-1 to 4 is as follows: dopamine is reacted with methacryloyl chloride according to a molar ratio of 1:1.2 to graft a carbon-carbon unsaturated double bond to obtain 3-methacryloyl dopamine, and 3-methacryloyl dopamine and maleic anhydride are copolymerized according to the component amount (the mass content of dopamine is 5%, 10%, 20% and 25% respectively). The specific experimental operation is as follows: 3-methacryloyl dopamine, maleic anhydride and initiator azobisisobutyronitrile are dissolved in anhydrous methanol at room temperature, and then the monomers are randomly copolymerized by initiating at 70°C under a nitrogen atmosphere. After 12h of reaction, the system is precipitated with ice-ether for three times to remove the unreacted components, and 3-methacryloyl dopamine-maleic anhydride copolymer-1 to 4 with different mass contents of 3-methacryloyl dopamine are obtained.

[0086] Unless otherwise specified, the component raw materials used in the embodiments and comparative examples of the present application are commercially available raw materials, and the component raw materials used in each parallel experiment are the same.

[0087] Examples 1 to 15 and Comparative Examples 1 to 4

[0088] The formulations of the polypropylene composite materials of Examples 1 to 15 and Comparative Examples 1 to 4 are shown in Tables 1 and 2 (all in parts by weight).

[0089] The preparation methods of the polypropylene composite materials of Examples 1 to 15 and Comparative Examples 1 to 4 all include the following steps:

[0090] According to the ratio, polypropylene resin, 3-methacryloyldopamine-maleic anhydride copolymer and nucleating agent are mixed evenly, put into a twin-screw extruder, melt-extruded at 170-210°C, and granulated to obtain masterbatch. The masterbatch is mixed evenly with acrylate monomer, photoreactant and chain transfer agent, and the reaction is initiated under light for 12 hours. The mixture is melt-extruded at 170-210°C and granulated to obtain a polypropylene composite material.

[0091] Table 1

[0092]

[0093]

[0094] Table 2

[0095]

[0096] Performance Testing

[0097] 1. Coating adhesion

[0098] 1.1 Peel Strength: The polypropylene composition prepared above was injection molded into 100*100*2 mm square specimens. Primer was sprayed onto the specimens, followed by baking at 80°C for 5 minutes. The basecoat was then applied, followed by baking at 80°C for 5 minutes. Clearcoat was then sprayed, followed by baking at 80°C for 30 minutes to produce the painted coating. The tensile strength of the coating peeled from the substrate was measured. The final test result was the average of three measurements, with the unit of peel strength being N / m. The test was conducted at a tensile speed of 50 mm / min, a peel width of 10 mm, and a peel angle of 180°. The test temperature was 23°C.

[0099] 1.2 High-pressure water jet: Test according to the method in DIN55662-2009, angle: 90°, water temperature: 60℃, distance: 100cm, time: 60s, water flow: 11.3L / min. Compare with the standard image in DIN55662-2009 and rate. The lower the grade, the better the coating adhesion.

[0100] 2. Heat aging resistance: After aging at 100°C for 42 days, the ISO 179 notched impact strength performance retention rate before and after aging was tested.

[0101] Table 3

[0102]

[0103] As can be seen from Table 3, the polypropylene composite material of the present invention has excellent coating adhesion and aging resistance, and is very suitable for the preparation of automotive parts, especially for the preparation of automotive bumpers. The polypropylene composite material of the present invention has a water impact resistance grade of ≤1, a peel strength of ≥1200 N / m, and a notched impact resistance retention rate of ≥80%, which can meet the use requirements of automotive spray-painted bumper parts.

[0104] Comparative Examples 1 to 4 show that the present invention further improves coating adhesion and aging resistance by controlling the amount of each raw material to: 00 parts of polypropylene resin, 20 to 25 parts of acrylate monomer, 0.2 to 0.25 parts of chain transfer agent, 0.2 to 0.25 parts of initiator, 5 to 8 parts of 3-methacryloyldopamine-maleic anhydride copolymer, and 0.15 to 0.25 parts of nucleating agent.

[0105] Comparing Example 2 with Examples 5 to 8, it can be seen that the present invention further improves coating adhesion and aging resistance by adopting a polypropylene resin with a melt flow rate of 20 to 32 g / 10 min.

[0106] Comparing Example 2 with Examples 13 to 15, it can be seen that the present invention further improves coating adhesion and aging resistance by adopting 3-methacryloyldopamine-maleic anhydride copolymer having a mass percentage of 10 to 20% of 3-methacryloyldopamine.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composite material, characterized in that The invention comprises the following components in parts by weight: 100 parts of polypropylene resin, 14 to 32 parts of acrylate monomer, 0.14 to 0.32 parts of chain transfer agent, 0.14 to 0.32 parts of initiator, 0.9 to 11 parts of 3-methacryloyldopamine-maleic anhydride copolymer, and 0.04 to 0.32 parts of nucleating agent; The mass percentage of 3-methacryloyldopamine in the 3-methacryloyldopamine-maleic anhydride copolymer is 5-25%.

2. The polypropylene composite material according to claim 1, characterized in that The mass percentage of 3-methacryloyldopamine in the 3-methacryloyldopamine-maleic anhydride copolymer is 10-20%.

3. The polypropylene composite material according to claim 1, characterized in that The melt flow rate of the polypropylene resin at 230° C. / 2.16 kg is 10-40 g / 10 min.

4. The polypropylene composite material according to claim 3, characterized in that The melt flow rate of the polypropylene resin at 230° C. / 2.16 kg is 20-32 g / 10 min.

5. The polypropylene composite material according to claim 1, characterized in that The acrylic acid ester monomer includes at least one of n-butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, butyl methacrylate, methyl methacrylate, methyl acrylate, hydroxypropyl methacrylate, and hydroxypropyl acrylate.

6. The polypropylene composite material according to claim 1, characterized in that The chain transfer agent includes at least one of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanylpentanoic acid, and 2-cyanomethyl-N-methyl-N-phenyldithiocarbamic acid.

7. The polypropylene composite material according to claim 1, characterized in that The initiator includes a benzophenone initiator; the benzophenone initiator includes at least one of Michler's ketone, benzophenone, 2-hydroxybenzophenone, 4-hydroxybenzophenone, 2,2'-dihydroxybenzophenone, 4-hydroxy-2'methylformate benzophenone, diphenoxybenzophenone, 4-methylbenzophenone or 2,4,6-trimethylbenzophenone.

8. The polypropylene composite material according to claim 1, characterized in that The nucleating agent includes at least one of an α-crystal nucleating agent and a β-crystal nucleating agent; The α-crystal nucleating agent includes at least one of an organic phosphate α-crystal nucleating agent, an organic carboxylate α-crystal nucleating agent, and a sorbitol α-crystal nucleating agent; The β-crystal nucleating agent includes at least one of an aromatic amide β-crystal nucleating agent and an organic carboxylic acid β-nucleating agent.

9. The method for preparing a polypropylene composite material according to any one of claims 1 to 8, wherein: The following steps are involved: According to the ratio, polypropylene resin, 3-methacryloyldopamine-maleic anhydride copolymer and nucleating agent are mixed evenly, put into a twin-screw extruder for melt extrusion, granulated to obtain masterbatch, the masterbatch is mixed evenly with acrylate monomer, photoreactant and chain transfer agent, the reaction is initiated under light, put into a twin-screw extruder for melt extrusion, granulated to obtain a polypropylene composite material.

10. Use of the polypropylene composite material according to any one of claims 1 to 8 in the preparation of automotive parts.

11. A spray-painted component, characterized in that: The polypropylene composite material is prepared by using any one of claims 1 to 8.

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