A flame-retardant ABS composite material for automobiles and preparation method thereof

Abstract

The present invention discloses a flame-retardant ABS composite material for automobiles and a preparation method thereof. The flame-retardant ABS composite material for automobiles comprises the following raw material components in parts by weight: 50-80 parts of ABS resin, 6-15 parts of a brominated flame retardant, 3-5 parts of silicon dioxide, 1-3 parts of a lubricant, 1-4 parts of an auxiliary agent, 4-7 parts of a synergist, and 1-2 parts of an antioxidant. The present invention also provides a preparation method thereof, wherein the raw material components are mixed and melted, extruded through a twin-screw extruder, and granulated to obtain a flame-retardant ABS composite material for automobiles. Compared with the prior art, the ABS composite material prepared by the present invention not only has excellent flame retardancy, but also has good Izod notched impact strength, UV aging resistance, and water resistance. At the same time, the antibacterial properties of the ABS composite material are improved, achieving long-lasting antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a flame-retardant ABS composite material for automobiles and a preparation method thereof. Background Art

[0002] ABS (Acrylonitrile Butadiene Styrene) resin refers to a copolymer of acrylonitrile, butadiene, and styrene. It is a thermoplastic polymer with high strength, excellent toughness, and easy processing and molding. It is widely used in the automotive, home appliance, machinery, textile, and other industries. In recent years, with the continuous improvement of vehicle lightweighting, ABS is commonly used in the manufacture of automotive parts such as instrument panels, exterior body panels, interior trim panels, steering wheels, sound insulation panels, door locks, bumpers, and ventilation ducts, resulting in a rapid increase in demand for ABS resin in the automotive industry. However, due to the many potential fire sources inside the vehicle, such as sparks generated by electrical system failures, many countries and regions have established strict flame retardant standards for automotive interior materials for safety reasons. Therefore, flame-retardant ABS composite materials with excellent flame retardancy are in high demand for the manufacture of automotive interior and some exterior components.

[0003] CN106589771A discloses a method for preparing highly flame-retardant ABS automotive interior parts. The flame-retardant ABS plastic produced by this invention exhibits excellent flame retardancy and is used to manufacture automotive interior parts with reliable quality and excellent safety. Flame-retardant materials for automotive interior parts include automotive roof fabrics, automotive carpets, trunk mats, trunk side trims, wheel arch mats, etc. However, the highly flame-retardant ABS automotive interior parts produced using the flame-retardant ABS plastic provided by this invention have only moderate antibacterial and waterproof properties, resulting in poor antibacterial durability, unstable antibacterial properties, and significantly reduced water-washability stability, further limiting the product's usability.

[0004] CN118931100A discloses a heat-resistant automotive ABS composite material and its preparation method. The heat-resistant automotive ABS composite material comprises the following raw materials in parts by weight: 80-90 parts ABS resin, 10-20 parts thermoplastic polyurethane, 10-20 parts modified filler, 5-15 parts silicone foam microspheres, 0.1-1 part lubricant, 0.1-1 part antioxidant, 1-2 parts flame retardant, and 3-8 parts mixed fiber. The ABS composite material provided by this invention has the advantages of strong heat resistance and good fluidity, is not prone to internal stress and cracking during injection molding, and has strong impact resistance. However, this ABS composite material has poor resistance to UV aging. Automotive exterior parts (such as bumpers and body panels) made from this ABS composite material will gradually lose their impact strength over time due to the effects of ultraviolet rays when exposed to outdoor environments for a long time, making them susceptible to damage in the event of a collision. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a flame-retardant ABS composite material for automobiles and a method for preparing the same. The ABS composite material prepared by the present invention not only exhibits excellent flame retardancy, but also exhibits good Izod notched impact strength, UV aging resistance, and water resistance. Furthermore, the antibacterial properties of the ABS composite material are enhanced, achieving long-lasting antibacterial properties.

[0006] To achieve the above object, the present invention provides a method for preparing a flame-retardant ABS composite material for automobiles, comprising the following steps:

[0007] (1) ABS resin, brominated flame retardant, lubricant, additive, antioxidant, silicon dioxide and synergist are mixed uniformly to obtain a mixture; the mixture is then added to an internal mixer at a mixing temperature of 100-150°C for 15-30 minutes to obtain a premix;

[0008] (2) The premix is ​​then fed into a twin-screw extruder for extrusion and granulation. The screw speed of the twin-screw extruder is 300-800 rpm and the barrel temperature is 160-220°C, thereby obtaining a flame-retardant ABS composite material for automobiles.

[0009] Preferably, the weight ratio of each raw material component is:

[0010] 50-80 parts of ABS resin, 6-15 parts of brominated flame retardant, 3-5 parts of silicon dioxide, 1-3 parts of lubricant, 1-4 parts of auxiliary agent, 4-7 parts of synergist, and 1-2 parts of antioxidant.

[0011] Preferably, the brominated flame retardant is selected from one or more of decabromodiphenylethane, brominated epoxy resin, tetrabromobisphenol A, and bromotriazine.

[0012] Preferably, the lubricant is selected from one or more of pentaerythritol stearate, paraffin wax, silicone powder, and ethylene bis stearamide;

[0013] The auxiliary agent is prepared by mixing epoxy soybean oil and epoxy modified silicone oil in a mass ratio of 1:1-3.

[0014] Preferably, the antioxidant is selected from one or more of antioxidant 1076, antioxidant 1010, antioxidant 168, antioxidant 3114, and antioxidant 1098.

[0015] Preferably, the preparation method of the synergist comprises the following steps, calculated by weight:

[0016] S1. Mix 4-6 parts of nanohydroxyapatite with 95-105 parts of ethanol, and then ultrasonically treat for 20-40 minutes to obtain a suspension; add 1-3 parts of urushiol to the suspension, mix and stir at 65-75°C for 2-4 hours to obtain a mixed solution; centrifuge the mixed solution, collect the precipitate, wash it with ethanol 2-3 times, and dry it at 43-48°C for 3-6 hours to obtain modified nanohydroxyapatite; then add 1-3 parts of modified nanohydroxyapatite to 45-55 parts of a copper chloride aqueous solution with a concentration of 0.8-1.5 g / L, and add 0.01-0.05 parts of anhydrous sodium acetate, and then mix and stir at 10-20 MPa and 80-100°C for 3-5 hours; cool and centrifuge, collect the precipitate, wash it with ethanol 1-2 times, then wash it with water 2-3 times, and dry it at 40-48°C for 8-15 hours to obtain antibacterial agent-loaded modified nanohydroxyapatite;

[0017] S2. Mix 8-12 parts of starch additive and 1-3 parts of antibacterial agent-modified nanohydroxyapatite prepared in step S1 with 95-105 parts of water, and then stir at 38-42°C and 200-400 rpm for 2-4 hours. Then, centrifuge at 2000-5000 rpm for 3-8 minutes, collect the precipitate, wash it with water 2-3 times, and dry it at 43-48°C for 30-60 minutes to obtain a synergist.

[0018] Preferably, the starch additive in step S2 is selected from at least one of porous starch and modified porous starch.

[0019] Preferably, the preparation method of the modified porous starch comprises the following steps, in parts by weight:

[0020] 0.5-1.5 parts of anhydrous sodium sulfate and 0.05-0.2 parts of sodium hydroxide are added to 95-105 parts of water and mixed evenly, then 4.5-5.5 parts of porous starch and 0.3-0.5 parts of a modifier are added, and the mixture is stirred at 40-60° C. for 2-5 hours; then the pH is adjusted to 5.8-6.2 with a 0.5-1 mol / L hydrochloric acid aqueous solution, filtered, and the precipitate is collected, washed with water 2-3 times, and then washed with a 90-95wt% ethanol aqueous solution 2-3 times, and dried at 38-45° C. for 8-12 hours to obtain a modified porous starch.

[0021] More preferably, the modifier is selected from benzyl iodide, benzyl bromide, and 1,4-dichlorobenzyl.

[0022] The present invention also provides a flame-retardant ABS composite material for automobiles, which is prepared by the above method.

[0023] Beneficial effects of the present invention:

[0024] 1. Compared with the prior art, the present invention prepares a flame-retardant ABS composite material for automobiles by mixing and melting ABS resin, a brominated flame retardant, silicon dioxide, a lubricant, an auxiliary agent, a synergist, and an antioxidant in a reasonable proportion, and then extruding and granulating the mixture. ABS resin is selected as the matrix of the composite material to provide the material with basic mechanical properties and processing performance. Meanwhile, the introduction of the brominated flame retardant bromotriazine as the main flame retardant component effectively improves the flame retardant properties of the composite material. Pentaerythritol stearate serves as a lubricant and demoulding agent, which helps improve the processing performance of the ABS composite material and helps ensure the surface quality of the finished product. Silica acts as a reinforcing agent, increasing the strength and hardness of the composite material and enhancing the mechanical properties of the material. It also improves the heat resistance and dimensional stability of the material to a certain extent, allowing the material to maintain good performance under different environmental conditions. The introduction of the antioxidant can effectively inhibit the occurrence of oxidation reactions, preventing the material from degradation and aging due to oxidation, extending the service life of the material, and maintaining the material's performance stability.

[0025] 2. The present invention selects epoxy soybean oil and epoxy-modified silicone oil as additives. Epoxidized soybean oil has a good plasticizing effect, which can increase the flexibility of the composite material, reduce its brittleness, and improve the material's impact resistance. Epoxy-modified silicone oil not only has a certain plasticizing effect, but also improves the material's surface properties, making the composite surface smoother and, to a certain extent, enhancing the material's weather resistance and stability. Furthermore, the introduction of epoxy soybean oil and epoxy-modified silicone oil can interact with silica through chemical bonding and physical adsorption, and also interact with ABS resin through chemical reactions and physical interactions, effectively improving the compatibility between silica and ABS resin, thereby enhancing the overall performance of the ABS composite material.

[0026] 3. Compared with the existing technology, the present invention prepares a synergist by mixing modified porous starch and modified nano-hydroxyapatite loaded with an antibacterial agent, and introduces the synergist into an ABS resin matrix to prepare a flame-retardant ABS composite material for automobiles. This is beneficial to enhancing the cantilever beam notched impact strength, anti-ultraviolet light aging performance and waterproof performance of the ABS composite material, while also improving the antibacterial performance of the ABS composite material, achieving long-term antibacterial effect. DETAILED DESCRIPTION

[0027] Parameters for specific chemical substances used, sources.

[0028] ABS resin, brand: 0215H, brand: Jilin Petrochemical;

[0029] Nanohydroxyapatite, average particle size: 20 nm, was obtained from Beijing Dekedaojin Technology Co., Ltd.;

[0030] Silicon dioxide, average particle size: 5 μm;

[0031] Epoxidized soybean oil, CAS number: 8013-07-8, was obtained from Nantong Runfeng Petrochemical Co., Ltd.

[0032] Epoxy modified silicone oil, brand: DY-E701, from Shandong Dayi Chemical Co., Ltd.

[0033] Urushiol, CAS number: 35237-02-6;

[0034] The preparation method of porous starch includes the following steps: dispersing a corn starch solution in a sodium acetate buffer solution with a pH of 5.5 to obtain a 30% (w / w) starch milk, then adding 2% (w / w) of a complex enzyme (α-amylase: saccharifying enzyme = 1:2), incubating at 50°C for 6 hours, then adjusting the pH to 3.0 to neutralize the system and incubating for 15 minutes; the system is centrifuged at 4000 r / min and washed three times with deionized water, and the finally obtained sample is dried at 40°C and passed through a 100-mesh sieve, and stored for later use.

[0035] Example 1

[0036] A method for preparing a flame-retardant ABS composite material for automobiles comprises the following steps:

[0037] (1) 75 parts by weight of ABS resin, 8 parts by weight of bromotriazine, 2 parts by weight of pentaerythritol stearate, 3 parts by weight of auxiliary agent, 1.5 parts by weight of antioxidant 1010, 4 parts by weight of silicon dioxide, and 5 parts by weight of synergist are mixed to obtain a mixture; the mixture is then added to an internal mixer at a mixing temperature of 120°C for 25 minutes to obtain a premix;

[0038] (2) The premix is ​​then fed into a twin-screw extruder for extrusion and granulation. The screw speed of the twin-screw extruder is 500 rpm and the barrel temperature is 190°C, thereby obtaining a flame-retardant ABS composite material for automobiles.

[0039] The auxiliary agent is prepared by mixing epoxy soybean oil and epoxy modified silicone oil in a mass ratio of 1:2.

[0040] The preparation method of the synergist comprises the following steps:

[0041] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0042] S2. 10 parts by weight of porous starch and 2 parts by weight of the antibacterial agent-modified nanohydroxyapatite prepared in step S1 were mixed with 100 parts by weight of water, and then stirred at 40°C and 300 rpm for 3 hours, and then centrifuged at 4000 rpm for 5 minutes. The precipitate was collected, washed three times with water, and dried at 45°C for 40 minutes to obtain a synergist.

[0043] Example 2

[0044] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0045] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0046] S2. Mix 10 parts by weight of modified porous starch and 2 parts by weight of the antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 100 parts by weight of water, and then stir at 40°C and 300 rpm for 3 hours, then centrifuge at 4000 rpm for 5 minutes, collect the precipitate, wash it three times with water, and dry it at 45°C for 40 minutes to obtain a synergist.

[0047] The preparation method of the modified porous starch comprises the following steps:

[0048] 1 part by weight of anhydrous sodium sulfate and 0.1 part by weight of sodium hydroxide were added to 100 parts by weight of water and mixed evenly, and then 5 parts by weight of porous starch and 0.4 parts by weight of 1,4-dichlorobenzyl were added, and the mixture was stirred at 50°C for 3 hours; then the pH was adjusted to 6 with a 1 mol / L hydrochloric acid aqueous solution, the precipitate was filtered, collected, washed 3 times with water, and then washed 3 times with a 90wt% ethanol aqueous solution, and dried at 40°C for 10 hours to obtain a modified porous starch.

[0049] Example 3

[0050] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0051] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0052] S2. Mix 10 parts by weight of modified porous starch and 2 parts by weight of the antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 100 parts by weight of water, and then stir at 40°C and 300 rpm for 3 hours, then centrifuge at 4000 rpm for 5 minutes, collect the precipitate, wash it three times with water, and dry it at 45°C for 40 minutes to obtain a synergist.

[0053] The preparation method of the modified porous starch comprises the following steps:

[0054] 1 part by weight of anhydrous sodium sulfate and 0.1 part by weight of sodium hydroxide were added to 100 parts by weight of water and mixed evenly, and then 5 parts by weight of porous starch and 0.4 parts by weight of benzyl bromide were added, and the mixture was stirred at 50° C. for 3 hours; then the pH was adjusted to 6 with a 1 mol / L hydrochloric acid aqueous solution, and the precipitate was collected by filtration, washed three times with water, and then washed three times with a 90 wt% ethanol aqueous solution, and dried at 40° C. for 10 hours to obtain a modified porous starch.

[0055] Example 4

[0056] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0057] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0058] S2. Mix 10 parts by weight of modified porous starch and 2 parts by weight of the antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 100 parts by weight of water, and then stir at 40°C and 300 rpm for 3 hours, then centrifuge at 4000 rpm for 5 minutes, collect the precipitate, wash it three times with water, and dry it at 45°C for 40 minutes to obtain a synergist.

[0059] The preparation method of the modified porous starch comprises the following steps:

[0060] 1 part by weight of anhydrous sodium sulfate and 0.1 part by weight of sodium hydroxide were added to 100 parts by weight of water and mixed evenly, and then 5 parts by weight of porous starch and 0.4 parts by weight of benzyl iodide were added, and the mixture was stirred at 50°C for 3 hours; then the pH was adjusted to 6 with a 1 mol / L hydrochloric acid aqueous solution, filtered, and the precipitate was collected, washed 3 times with water, and then washed 3 times with a 90wt% ethanol aqueous solution, and dried at 40°C for 10 hours to obtain a modified porous starch.

[0061] Comparative Example 1

[0062] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0063] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0064] S2. Mix 10 parts by weight of modified porous starch and 2 parts by weight of the antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 100 parts by weight of water, and then stir at 40°C and 300 rpm for 3 hours, then centrifuge at 4000 rpm for 5 minutes, collect the precipitate, wash it three times with water, and dry it at 45°C for 40 minutes to obtain a synergist.

[0065] The preparation method of the modified porous starch comprises the following steps:

[0066] 1 part by weight of anhydrous sodium sulfate and 0.1 part by weight of sodium hydroxide were added to 100 parts by weight of water and mixed evenly, and then 5 parts by weight of porous starch and 0.4 parts by weight of methylbenzyl chloride were added, and the mixture was stirred at 50° C. for 3 hours; then the pH was adjusted to 6 with a 1 mol / L hydrochloric acid aqueous solution, and the precipitate was collected by filtration, washed three times with water, and then washed three times with a 90wt% ethanol aqueous solution, and dried at 40° C. for 10 hours to obtain a modified porous starch.

[0067] Comparative Example 2

[0068] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0069] S1. 5 parts by weight of nano-hydroxyapatite were mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of tannic acid were added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution was centrifuged, the precipitate was collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nano-hydroxyapatite; then 2 parts by weight of the modified nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifuged, the precipitate was collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite;

[0070] S2. Mix 10 parts by weight of modified porous starch and 2 parts by weight of the antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 100 parts by weight of water, and then stir at 40°C and 300 rpm for 3 hours, then centrifuge at 4000 rpm for 5 minutes, collect the precipitate, wash it three times with water, and dry it at 45°C for 40 minutes to obtain a synergist.

[0071] The preparation method of the modified porous starch is consistent with that of Example 4.

[0072] Comparative Example 3

[0073] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0074] 5 parts by weight of nanohydroxyapatite are mixed with 100 parts by weight of ethanol, and then ultrasonically treated for 30 minutes to obtain a suspension; 2 parts by weight of urushiol are added to the suspension, mixed and stirred at 70°C for 3 hours to obtain a mixed solution; the mixed solution is centrifuged, the precipitate is collected, washed with ethanol 3 times, and dried at 45°C for 5 hours to obtain modified nanohydroxyapatite; then 2 parts by weight of modified nanohydroxyapatite are added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate are added, and then mixed and stirred at 12 MPa and 90°C for 4 hours; after cooling, centrifugation is carried out, the precipitate is collected, washed with ethanol 2 times, then washed with water 3 times, and dried at 45°C for 12 hours to obtain antibacterial agent-loaded modified nanohydroxyapatite, i.e., a synergist.

[0075] Comparative Example 4

[0076] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that the method for preparing the synergist comprises the following steps:

[0077] Then, 2 parts by weight of nano-hydroxyapatite were added to 50 parts by weight of a 1 g / L copper chloride aqueous solution, and 0.03 parts by weight of anhydrous sodium acetate were added, followed by mixing and stirring at 12 MPa and 90°C for 4 hours; after cooling, the mixture was centrifuged, the precipitate was collected, washed twice with ethanol, then washed three times with water, and dried at 45°C for 12 hours to obtain nano-hydroxyapatite loaded with an antibacterial agent, i.e., a synergist.

[0078] Comparative Example 5

[0079] A method for preparing a flame-retardant ABS composite material for automobiles, which differs from Example 1 in that no synergist is added, namely:

[0080] (1) 75 parts by weight of ABS resin, 8 parts by weight of bromotriazine, 2 parts by weight of pentaerythritol stearate, 3 parts by weight of auxiliary agent, 1.5 parts by weight of antioxidant 1010, and 4 parts by weight of silicon dioxide were mixed uniformly to obtain a mixture; the mixture was then added to an internal mixer at a mixing temperature of 120° C. for 25 minutes to obtain a premix;

[0081] (2) The premix is ​​then fed into a twin-screw extruder for extrusion and granulation. The screw speed of the twin-screw extruder is 500 rpm and the barrel temperature is 190°C, thereby obtaining a flame-retardant ABS composite material for automobiles.

[0082] The auxiliary agent is prepared by mixing epoxy soybean oil and epoxy modified silicone oil in a mass ratio of 1:2.

[0083] Test Example 1

[0084] Performance Testing

[0085] The ABS composite materials prepared in the Examples and Comparative Examples were dried in a forced-air oven at 80°C for 4 hours and then injection-molded into standard bars and square plates using a plastic injection molding machine at a molding temperature of 210°C. The molded bars and square plates were then conditioned at 50% relative humidity and 23°C for at least 24 hours before performance testing. The testing was conducted as follows:

[0086] Combustion performance: The flame retardant grade of 1.6mm standard specimens was tested according to UL94-2009 standard;

[0087] Contact angle: The injection molded square plate is tested using the shape image analysis method and the angle measurement method;

[0088] Izod notched impact strength: Injection molded into rod-shaped specimens that meet the requirements of ISO 180:2023 Izod notched impact strength test, and perform Izod notched impact strength test at 25°C with reference to ISO 180:2023 standard;

[0089] UV aging resistance: wavelength is 340nm, irradiation intensity is 0.08W / m 2 The sample was irradiated with a deuterium lamp for 600 hours for UV aging. The notched Izod impact strength of the sample after UV aging was then tested again with reference to ISO 180:2023. The loss rate of notched Izod impact strength of the sample before and after light aging was used to test its resistance to UV aging. The loss rate of notched Izod impact strength was calculated as follows:

[0090] Loss rate (%) = (N0-N1) / N0×100%

[0091] Where N0 is the notched cantilever beam impact strength before light aging (KJ / m 2 ); N1 is the notched cantilever beam impact strength after light aging (KJ / m 2 );

[0092] The test results are shown in Table 1:

[0093] Table 1

[0094]

[0095] As can be seen from Table 1, the flame retardancy ratings of the examples and comparative examples are all V-0, indicating that the ABS composite materials prepared in Examples 1-4 and Comparative Examples 1-5 of the present invention all have good flame retardancy.

[0096] Comparing Examples 1-4 and Comparative Examples 1-5, it can be seen that the notched Izod impact strength of Examples 1-4 and Comparative Examples 1-3 is significantly higher than that of Comparative Examples 4-5, and the notched Izod impact strength loss rate after UV aging is significantly lower than that of Comparative Examples 4-5, indicating that the synergist introduced in Examples 1-4 and Comparative Examples 1-3 of the present invention is beneficial for improving the notched Izod impact strength and UV aging resistance of the ABS composite material. The notched Izod impact strength of Examples 2-4 and Comparative Example 1 is higher than that of Example 1 and Comparative Examples 2-3, and the UV aging resistance is better than that of Example 1 and Comparative Examples 2-3. This may be because the modified porous starch is introduced during the preparation of the synergist in Examples 2-4 and Comparative Example 1. The porous structure of the modified porous starch can adsorb nanohydroxyapatite, preventing its agglomeration, and at the same time improves the compatibility between the antibacterial agent-loaded modified nanohydroxyapatite and the ABS resin matrix. The uniformly dispersed synergist can more effectively exert its reinforcing effect on the ABS composite material, which is beneficial for improving the notched Izod impact strength of the ABS composite material. Under ultraviolet irradiation, chemical bonds (such as double bonds) in ABS resin undergo photooxidation reactions, leading to molecular chain breakage and crosslinking. Consequently, as the aging process progresses, the material's structure is destroyed, resulting in surface cracking and pulverization, which in turn leads to reduced Izod impact strength. The introduction of benzyl groups into the modified porous starch absorbs UV energy, reducing its impact on the ABS resin and improving the ABS composite's resistance to UV aging. The Izod impact strength and UV aging resistance of Examples 2-4 are higher than those of Comparative Example 1. This may be because the larger chlorine, bromine, and iodine atoms in the modifiers 1,4-dichlorobenzyl, benzyl bromide, and benzyl iodide used in Examples 2-4 increase the molecular size and structural complexity of the modified starch molecules. When ultraviolet light enters the ABS composite, these larger atoms cause more scattering and reflection of the light within the composite, increasing the UV transmission path within the composite and the probability of UV absorption and scattering. However, the relatively small structure of methylbenzyl chloride has weaker scattering and reflection effects on light, and ultraviolet rays can more easily penetrate ABS composite materials, resulting in poor anti-ultraviolet light aging performance.

[0097] Comparing Examples 1-4 with Comparative Examples 1-5, it can be seen that the contact angles of Examples 2-4 and Comparative Example 1 are significantly greater than those of Example 1 and Comparative Examples 2-5, indicating that the synergists introduced in Examples 2-4 and Comparative Example 1 of the present invention are beneficial for improving the water resistance of ABS composite materials. This may be because, during the preparation of the synergists, 1,4-dichlorobenzyl, benzyl bromide, benzyl iodide, and p-methylbenzyl chloride were used as modifiers to modify the porous starch. The introduction of benzyl groups into the starch molecules altered the overall chemical structure of the starch. The hydrophobic benzyl groups partially obscured the numerous hydroxyl groups in the starch molecules, reducing interactions between the starch molecules and water molecules, thereby enhancing their hydrophobicity.

[0098] Comparing Examples 2-4 and Comparative Example 1, it can be found that the contact angle of Examples 2-4 is greater than that of Comparative Example 1, among which Example 4 has the largest contact angle, reaching 105°. The reason for this may be that under the same reaction conditions, the reactivity of the modifiers 1,4-dichlorobenzyl, benzyl bromide, and benzyl iodide used in Examples 2-4 is significantly better than that of p-methylbenzyl chloride. The leaving ability of the chlorine, bromine, and iodine atoms in 1,4-dichlorobenzyl, benzyl bromide, and benzyl iodide is relatively strong, among which benzyl iodide is the strongest. Therefore, when reacting with starch, it is easier to undergo substitution reaction with the hydroxyl groups on the starch molecules, thereby more efficiently introducing hydrophobic groups into the starch molecules. The presence of methyl in p-methylbenzyl chloride may affect the leaving activity of the chlorine atom to a certain extent, resulting in a relatively low reaction efficiency with starch, a relatively small number of introduced hydrophobic groups, and a less obvious improvement in hydrophobicity.

[0099] Comparing Example 1 with Comparative Examples 2-5, it was found that the contact angle of Comparative Example 5 without the addition of a synergist was greater than 90°, showing good hydrophobicity, while the contact angles of Example 1 and Comparative Examples 2-4 with the addition of a synergist were ≤90°, indicating poor hydrophobicity. Analysis suggests that the reason may be that the porous starch contained in the synergist in Example 1 is hydrophilic, resulting in a decrease in hydrophobicity; the tannic acid in Comparative Example 2 introduces hydrophilic phenolic hydroxyl groups, further reducing hydrophobicity; the hydrophilic groups on the surface of the nanohydroxyapatite in Comparative Example 4 cause its hydrophobicity to decrease; and Comparative Example 3, due to the replacement of the hydrophilic groups of the nanohydroxyapatite after urushiol modification and the introduction of a long hydrophobic carbon chain, exhibits better hydrophobicity than Example 1, Comparative Example 2, and Comparative Example 4.

[0100] Test Example 2

[0101] Antibacterial performance test

[0102] The flame-retardant ABS composite materials for automobiles prepared in Examples 1-4 of the present invention and Comparative Examples 1-5 were left to stand naturally at room temperature for 100 days. The antibacterial properties of the flame-retardant ABS composite materials for automobiles prepared in Examples 1-4 of the present invention and Comparative Examples 1-5 were then tested according to the test method provided in the standard "GB / T 31402-2023 Determination of Antibacterial Activity on the Surfaces of Plastics and Other Non-porous Materials." The experimental bacteria species were: Escherichia coli (commercially available, number: ATCC 8739) and Staphylococcus aureus (commercially available, number: ATCC 6538P).

[0103] The test results are shown in Table 2:

[0104] Table 2

[0105]

[0106] As shown in Table 2, the antibacterial properties of each example and comparative example were tested after an initial storage period of up to 100 days. Comparing Examples 1-4 and Comparative Examples 1-5, it can be seen that the antibacterial rates against E. coli and Staphylococcus aureus in Examples 1-4 and Comparative Examples 1-4, which added a synergist, were significantly higher than those in Comparative Example 5, which did not add a synergist. Comparing Examples 1-4 and Comparative Examples 1-4, it can be seen that the antibacterial rates against E. coli and Staphylococcus aureus in Examples 2-4 and Comparative Example 1 were similar, both exceeding 99%, and higher than those in Example 1 and Comparative Examples 2-4. This demonstrates that the introduction of modified porous starch during the synergist preparation process improves the antibacterial effect of the ABS composite material and achieves long-term antibacterial activity.

[0107] Comparing Example 1 with Comparative Examples 2-4, it was found that the antibacterial rates of Example 1 and Comparative Example 2, in which porous starch was introduced during the preparation of the synergist, were higher than those of Comparative Examples 3-4. The reason for this may be that porous starch has excellent adsorption properties, which, when combined with the modified nanohydroxyapatite loaded with the antibacterial agent, can fix the antibacterial ions in the modified nanohydroxyapatite, avoid the precipitation of the antibacterial ions of the modified nanohydroxyapatite, and improve the antibacterial properties. The antibacterial rate of Example 1, in which urushiol-modified nanohydroxyapatite was used, was higher than that of Comparative Example 2, in which tannic acid-modified nanohydroxyapatite was used. The reason for this may be that, compared to tannic acid, urushiol contains long unsaturated carbon side chains, which have good interfacial compatibility with the soft and hard segments of ABS resin. During the blending process, the double bonds of the unsaturated long side chains are opened, forming a cross-linked interpenetrating network structure with the ABS resin, increasing the compatibility of nanohydroxyapatite with ABS resin, making it evenly dispersed in the ABS resin, which is beneficial to improving the antibacterial properties.

[0108] Comparing Comparative Example 3 and Comparative Example 4, it was found that the antibacterial rate of Comparative Example 3 using urushiol-modified nanohydroxyapatite loaded antibacterial agent as a synergist was higher than that of Comparative Example 4 using nanohydroxyapatite loaded antibacterial agent as a synergist. The reason for this may be that the urushiol-modified nanohydroxyapatite is mixed with metal copper ions, and the urushiol modified on the nanohydroxyapatite loads Cu through metal chelation coordination. 2+ , which enhances the copper ion loading capacity of nanohydroxyapatite, making the copper ion loading capacity of urushiol-modified nanohydroxyapatite higher than that of unmodified nanohydroxyapatite, thus improving the antibacterial performance. 2+ The strong coordination effect of ions makes most of the Cu 2+ The ions are anchored in the ABS composite material, and compared with nanohydroxyapatite, only a small amount of Cu 2+ Ions are dissolved from the surface of the ABS composite material, and the amount of dissolved metal ions is small, which is beneficial for the ABS composite material to maintain its antibacterial effect for a longer time.

Claims

1. A method for preparing a flame-retardant ABS composite material for automobiles, characterized in that: The following steps are involved: (1) ABS resin, brominated flame retardant, lubricant, additive, antioxidant, silicon dioxide and synergist are mixed uniformly to obtain a mixture; the mixture is then added to an internal mixer at a mixing temperature of 100-150°C for 15-30 minutes to obtain a premix; (2) The premix is ​​then fed into a twin-screw extruder for extrusion and granulation. The screw speed of the twin-screw extruder is 300-800 rpm and the barrel temperature is 160-220°C to obtain a flame-retardant ABS composite material for automobiles. The auxiliary agent is prepared by mixing epoxy soybean oil and epoxy modified silicone oil in a mass ratio of 1:1-3; The preparation method of the synergist comprises the following steps, calculated by weight: S1. Mix 4-6 parts of nanohydroxyapatite with 95-105 parts of ethanol, and then ultrasonicate for 20-40 minutes to obtain a suspension; 1-3 parts of urushiol are added to the suspension, mixed and stirred at 65-75°C for 2-4 hours to obtain a mixed solution; the mixed solution is centrifuged, the precipitate is collected, washed with ethanol 2-3 times, and dried at 43-48°C for 3-6 hours to obtain modified nano-hydroxyapatite; then 1-3 parts of the modified nano-hydroxyapatite are added to 45-55 parts of a 0.8-1.5 g / L copper chloride aqueous solution, and 0.01-0.05 parts of anhydrous sodium acetate are added, and then mixed and stirred at 10-20 MPa and 80-100°C for 3-5 hours; after cooling, centrifugation is performed, the precipitate is collected, washed with ethanol 1-2 times, then washed with water 2-3 times, and dried at 40-48°C for 8-15 hours to obtain antibacterial agent-loaded modified nano-hydroxyapatite; S2, mixing 8-12 parts of starch additive and 1-3 parts of antibacterial agent-loaded modified nanohydroxyapatite prepared in step S1 with 95-105 parts of water, and then stirring at 38-42° C. and 200-400 rpm for 2-4 hours, and then centrifuging at 2000-5000 rpm for 3-8 minutes, collecting the precipitate, washing it with water 2-3 times, and drying it at 43-48° C. for 30-60 minutes to obtain a synergist; The starch additive in step S2 is modified porous starch; The preparation method of the modified porous starch comprises the following steps, calculated by weight: 0.5-1.5 parts of anhydrous sodium sulfate and 0.05-0.2 parts of sodium hydroxide are added to 95-105 parts of water and mixed evenly, then 4.5-5.5 parts of porous starch and 0.3-0.5 parts of a modifier are added, and the mixture is stirred at 40-60° C. for 2-5 hours; then the pH is adjusted to 5.8-6.2 with a 0.5-1 mol / L hydrochloric acid aqueous solution, filtered, and the precipitate is collected, washed with water 2-3 times, and then washed with a 90-95 wt% ethanol aqueous solution 2-3 times, and dried at 38-45° C. for 8-12 hours to obtain a modified porous starch; The modifier is selected from one of benzyl iodide, benzyl bromide, and 1,4-dichlorobenzyl.

2. The method for preparing a flame-retardant ABS composite material for automobiles according to claim 1, wherein: The weight ratio of each raw material component is: 50-80 parts of ABS resin, 6-15 parts of brominated flame retardant, 3-5 parts of silicon dioxide, 1-3 parts of lubricant, 1-4 parts of auxiliary agent, 4-7 parts of synergist, and 1-2 parts of antioxidant.

3. The method for preparing a flame-retardant ABS composite material for automobiles according to claim 1 or 2, wherein: The brominated flame retardant is selected from one or more of decabromodiphenylethane, brominated epoxy resin, tetrabromobisphenol A, and bromotriazine.

4. The method for preparing a flame-retardant ABS composite material for automobiles according to claim 1 or 2, wherein: The lubricant is selected from one or more of pentaerythritol stearate, paraffin, silicone powder, and ethylene bis stearamide.

5. The method for preparing a flame-retardant ABS composite material for automobiles according to claim 1 or 2, wherein: The antioxidant is selected from one or more of antioxidant 1076, antioxidant 1010, antioxidant 168, antioxidant 3114, and antioxidant 1098.

6. A flame-retardant ABS composite material for automobiles, characterized by: The method is prepared by any one of claims 1 to 5.

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