Flame-retardant ABS material for automobiles and preparation method thereof

Abstract

The application relates to a kind of automobile flame-retardant ABS materials and its preparation method, belong to flame-retardant material technical field.Flame-retardant ABS material includes the following weight parts components: ABS resin 100 parts, composite flame retardant 20-30 parts, toughening agent 10-15 parts, antioxidant 0.4-0.6 parts and lubricant 1.2-1.8 parts;Composite flame retardant is with magnesium hydroxide as core, surface chemical grafting phosphorus silicon modification layer, the compatibility and dispersibility of composite flame retardant in matrix are significantly improved by blending composite flame retardant with ABS, the compatibility and dispersibility of composite flame retardant in matrix are significantly improved by the long chain alkyl side chain uniformly distributed in modification layer molecule, migration segregation is inhibited, phosphorus catalytic alkyl chain is carbonized when burning, silicon is strengthened to form dense carbon-silicon composite layer, magnesium hydroxide decomposition gas is inhibited to escape and form closed heat insulation microstructure, the sustained spread of combustion is inhibited, and the stability of material strength is maintained.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, specifically, it relates to a flame retardant ABS material for automobiles and its preparation method. Background Technology

[0002] Acrylonitrile-butadiene-styrene copolymer (ABS) is a thermoplastic engineering plastic with excellent comprehensive properties. It combines the chemical resistance and high strength of acrylonitrile, the impact resistance of butadiene, and the processability and surface gloss of styrene. Furthermore, it exhibits low molding shrinkage and good dimensional stability, making it widely used in automotive interior parts, dashboard housings, center console panels, door trim panels, and other automotive components. In particular, with the deepening trend of automotive lightweighting, the proportion of ABS and its modified materials in automotive plastics continues to increase.

[0003] However, ABS itself has a low limiting oxygen index and is a flammable material. During combustion, the flame spreads rapidly and produces a large amount of black smoke and molten droplets, which severely restricts its safe application in automotive materials. With the rapid development of new energy vehicles, the power battery system has placed more stringent requirements on the flame retardant safety level of surrounding materials, and the flame retardant modification of automotive ABS materials has become a key technical problem that urgently needs to be solved.

[0004] To achieve flame retardant properties in ABS, the main method currently involves adding flame retardants to the matrix. Based on the type of flame retardant, existing technologies can be categorized as follows: First, halogenated flame retardants (mainly bromine-based) offer high flame retardant efficiency, require low dosage, and exhibit strong interactions between the highly polar nitrile groups and polar halogen atoms in the ABS molecule, thus having a relatively small impact on mechanical properties. However, halogenated flame retardants release large amounts of toxic and corrosive gases such as hydrogen halides during combustion, and their application is increasingly limited with the implementation of environmental directives such as RoHS. Second, phosphorus-based, nitrogen-based, and their composite flame retardants (such as ammonium polyphosphate, phosphate esters, and phosphosilicates) achieve good flame retardant effects through the synergistic effect of gas-phase free radical quenching and condensed-phase char formation. However, the polarity difference between these flame retardants and the ABS matrix leads to poor compatibility, weak interfacial bonding, and a tendency to form stress concentration points, resulting in a significant decrease in the material's impact strength, elongation at break, and other mechanical properties. Furthermore, these flame retardants are expensive, making them uneconomical for applications requiring high flame retardant ratings. Thirdly, there are inorganic flame retardants (represented by magnesium hydroxide), which are completely halogen-free, inexpensive, and have good thermal stability. When heated, they exert their flame-retardant effect by absorbing heat, cooling down, and releasing water vapor to dilute flammable gases. However, inorganic flame retardants have lower flame-retardant efficiency, and a filling amount as high as 50% is often required to achieve a satisfactory flame-retardant rating. Such a high addition will severely degrade the mechanical properties of ABS, while also causing a sharp increase in melt viscosity, worsening processing fluidity, and making injection molding difficult.

[0005] To address the aforementioned issues, existing technologies have explored the use of composite blends of different types of flame retardants to achieve a balance between flame retardant performance, mechanical properties, and processing performance. For example, toughening agents or compatibilizers can be added to improve the interfacial bonding between the flame retardant and the matrix; synergists can be introduced to enhance flame retardant efficiency; or a blend of inorganic and phosphorus-based flame retardants can be employed. However, these physical blending methods still struggle to fundamentally resolve the issues of uneven dispersion and interfacial compatibility of flame retardants in the matrix. Segregation and agglomeration of flame retardants persist, and the synergistic effect between different components in the blended system is often limited by the degree of mixing uniformity. Therefore, developing flame retardants and ABS composite materials that exhibit good compatibility with the ABS matrix, high flame retardant efficiency, and minimal negative impact on mechanical properties has significant technological and industrial value. Summary of the Invention

[0006] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide a flame-retardant ABS material for automobiles and its preparation method.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A flame-retardant ABS material for automobiles comprises the following components in parts by weight: 100 parts ABS resin, 20-30 parts composite flame retardant, 10-15 parts toughening agent, 0.4-0.6 parts antioxidant, and 1.2-1.8 parts lubricant.

[0009] This composite flame retardant is prepared by the following method:

[0010] Step A1: Disperse undecenol in anhydrous tetrahydrofuran, continuously purge with dry nitrogen, cool in an ice-water bath, slowly add long-chain alkyl dichlorosilane and stir for 2-3 hours, then raise to room temperature and add triethylamine to continue the reaction for 0.5-1 hours. After the reaction is complete, filter to remove triethylamine salt, and rotary evaporate tetrahydrofuran to obtain the modified monomer.

[0011] In step A1, the molar ratio of long-chain alkyl dichlorosilane to undecenol is 1:2, and the amount of triethylamine used is 30-40 mol of undecenol; the long-chain alkyl dichlorosilane is preferably one of dioctyl dichlorosilane and methyl dodecyl dichlorosilane; undecenol is substituted with dichlorosilane and grafted with dibranched alkenyl groups.

[0012] Step A2: Under dry nitrogen protection, the modified monomer and hypophosphoric acid are dispersed in anhydrous toluene. The water bath temperature is controlled at 65-80℃. Benzoyl peroxide is added intermittently and the mixture is stirred for 8-10 hours. After the reaction is completed, the toluene is recovered by rotary evaporation under reduced pressure to obtain the modified matrix.

[0013] In step A2, the molar ratio of the modified monomer to hypophosphite is 1:0.75-0.82, and the amount of benzoyl peroxide is 0.9-1.2 wt% of the total amount of both. Under the initiation of benzoyl peroxide, the active PH bond in the hypophosphite molecule undergoes an addition reaction with the double bond in the modified monomer molecule to form a linear alkylphosphino acid compound.

[0014] Step A3: Mix the modified matrix, 4-dimethylaminopyridine and anhydrous dioxane, heat to 80-90℃, slowly add γ-glycidyl etheroxypropyltrimethoxysilane and stir for 5-7 hours. After the reaction is completed, reduce the pressure and rotary evaporate to recover the dioxane to obtain the phosphorus-silicon modifier.

[0015] In step A3, the ratio of the modified matrix to γ-glycidoxypropyltrimethoxysilane is 100g:30-40mmol, and 4-dimethylaminopyridine is 0.5-0.8wt% of the total amount of both. The epoxy group of γ-glycidoxypropyltrimethoxysilane ring-opens with the P-OH on the side chain of the modified matrix molecule, and the side chain trimethoxysilane is grafted.

[0016] Step A4: Disperse magnesium hydroxide micro powder in water using ultrasonication. Dissolve phosphorus-silicon modifier in dimethylacetamide and add it to the dispersion. Stir for 24 hours, centrifuge to separate the precipitate, and dry to obtain the composite flame retardant.

[0017] In step A4, the mass ratio of magnesium hydroxide micro powder to phosphorus-silicon modifier is 100:15-22; the average particle size of magnesium hydroxide micro powder is not higher than 10 μm; the phosphorus-silicon modifier side chain trimethoxysilane is coupled and loaded on the surface of magnesium hydroxide to form a composite.

[0018] A method for preparing a flame-retardant ABS material for automobiles, specifically comprising: mixing the components, using a twin-screw extruder for melt blending, extrusion, cooling, and granulation to obtain the flame-retardant ABS material.

[0019] Furthermore, the melt blending temperature range of the twin-screw extruder is 190-230℃.

[0020] The beneficial effects of this invention are:

[0021] The present invention provides a flame-retardant ABS material for automobiles and its preparation method. It employs a composite flame retardant with magnesium hydroxide microparticles as the core and a phosphorus-silicon modifier chemically grafted onto its surface, which is introduced into the ABS matrix, achieving significant technical effects. Compared with existing technologies, its effects are as follows:

[0022] This phosphorus-silicon modifier has a chain polymer structure with long-chain alkyl segments uniformly introduced into its molecular side chains. These long-chain alkyl segments have similar organic structural characteristics to the polybutadiene and polystyrene segments in ABS resin, thus endowing the composite flame retardant with excellent interfacial compatibility with the ABS matrix. When this composite flame retardant is loaded onto the surface of magnesium hydroxide particles, a uniform and dense long-chain alkyl modification layer is formed around the particles. This modification layer significantly reduces the melting resistance of inorganic magnesium hydroxide particles in the ABS matrix during melt blending, allowing the flame retardant to be uniformly dispersed in the matrix at the nanoscale. This avoids the agglomeration and stress concentration defects that are easily caused by the hydrophilic and oleophobic properties of traditional inorganic flame retardants. Meanwhile, since the modifier in the composite flame retardant is firmly anchored to the surface of the magnesium hydroxide core in the form of chemical bonds, and the magnesium hydroxide particles themselves have low thermodynamic migration in the matrix, the composite flame retardant can maintain a stable distribution state during melt blending and subsequent injection molding, without significant segregation and migration. This provides a continuous and stable flame retardant protection effect for ABS materials and effectively avoids the deterioration of mechanical properties caused by uneven distribution of flame retardants.

[0023] More importantly, in terms of flame retardant performance, the composite flame retardant exhibits a core-shell structure. Under high-temperature ignition conditions, the phosphorus-silicon compounds in the shell layer of the composite flame retardant decompose first. Among them, the phosphorus structure introduced by hypophosphoric acid decomposes to generate phosphorus-containing active substances. These phosphorus-containing active substances preferentially catalyze the decomposition of long-chain alkyl segments of the side chains into fine and dense carbide skeletons, forming a preliminary carbonized protective layer. At the same time, the silicon element contained in the modifier forms silicides after decomposition, which have a composite strengthening effect with the fine carbides, constructing a dense and high-temperature resistant carbon-silicon composite structure layer at the interface between the composite flame retardant and the ABS matrix. This carbon-silicon composite layer effectively suppresses the explosive escape of water vapor and gaseous products released during the thermal decomposition of magnesium hydroxide nuclei, preventing the interconnected voids formed by gas escape from disrupting the matrix structure and thus maintaining the material's structural integrity and mechanical properties during flame retardancy. Furthermore, due to the excellent dispersion uniformity of the composite flame retardant within the matrix, numerous independent, closed microstructure voids can form within the material during combustion. These void structures effectively block heat conduction to deeper layers of the material, inhibiting the continued spread of combustion. This synergistic effect allows the material to maintain its structural strength without sudden collapse when exposed to flame, while also effectively preventing further heat transfer to the interior, thereby significantly reducing safety risks under high-temperature ignition conditions.

[0024] In summary, this invention constructs an inorganic-organic composite flame retardant system that unifies compatibility, dispersibility, and flame retardant efficiency by introducing a chemically bonded modification layer with both alkyl compatibilizing segments and phosphorus-silicon char-forming components onto the surface of the magnesium hydroxide core. This effectively overcomes the technical bottlenecks in existing technologies, such as poor compatibility between flame retardants and the matrix, uneven dispersion, and difficulty in balancing flame retardancy and mechanical properties. It has outstanding technological advancement and industrial application value in the field of flame-retardant ABS. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Preparation of flame-retardant ABS material for automobiles. The specific implementation process is as follows:

[0027] 1) Preparation of composite flame retardants

[0028] Step A1: Undecenol and anhydrous tetrahydrofuran were mixed and stirred. Dry nitrogen gas was introduced until a stable gas flow was observed. The mixture was cooled to below 5°C using an ice-water bath. Dioctyldichlorosilane was slowly added and stirred for 3 hours. After the addition was complete, the ice-water bath was removed. The mixture was allowed to return to room temperature, and a small amount of triethylamine was added and the reaction was continued for 1 hour. The reactants used in the reaction were: 0.1 mol dioctyldichlorosilane, 0.2 mol undecenol, 40 mol% triethylamine of undecenol, and 280 mL anhydrous tetrahydrofuran. After the reaction was completed, the triethylamine salt was removed by filtration, and the tetrahydrofuran was recovered by rotary evaporation to obtain the modified monomer.

[0029] Step A2: Under dry nitrogen protection, the modified monomer, hypophosphite, and anhydrous toluene were mixed and stirred. The water bath temperature was controlled at 65℃. Benzoyl peroxide was added in three portions, intermittently over 2 hours, for a total reaction time of 10 hours. The amounts of raw materials used in the reaction were: 0.1 mol of modified monomer, 82 mmol of hypophosphite, 1.2 wt% of the total amount of benzoyl peroxide, and 450 mL of anhydrous toluene. After the reaction was completed, the toluene was recovered by rotary evaporation under reduced pressure to obtain the modified matrix.

[0030] Step A3: Take the modified matrix, 4-dimethylaminopyridine and anhydrous dioxane and stir to mix. Heat to 80℃ and slowly add γ-glycidyl etheroxypropyltrimethoxysilane and stir to react for 7h. The amount of raw materials used in the reaction is: 50g modified matrix, 20mmol γ-glycidyl etheroxypropyltrimethoxysilane, 0.8wt% of the total amount of 4-dimethylaminopyridine, and 330mL anhydrous dioxane. After the reaction is completed, dioxane is recovered by rotary evaporation under reduced pressure to obtain the phosphorus-silicon modifier.

[0031] Step A4: Take magnesium hydroxide micro powder and water and ultrasonically disperse to prepare a dispersion with a solid content of 10wt%. Dissolve the phosphorus-silicon modifier in dimethylacetamide and add the solution to the dispersion and stir for 24h. The raw materials used in the reaction are: 100g magnesium hydroxide micro powder, YTM-8 type micro powder with an average particle size of 8μm, and 15g phosphorus-silicon modifier. Centrifuge to separate the bottom precipitate and dry it to obtain the composite flame retardant.

[0032] 2) Preparation of flame-retardant ABS

[0033] Raw materials are prepared by weight as follows: 100 parts of ABS resin, XR404-9001 type resin raw material; 30 parts of composite flame retardant, prepared in this embodiment; 15 parts of toughening agent, M-701 type MBS (methyl methacrylate-butadiene-styrene) toughening agent; 0.4 parts of antioxidant, which is a mixture of antioxidant 1076 and antioxidant 168 in equal weight ratio; 1.2 parts of lubricant, ethylene bis-stearamide.

[0034] The above raw materials are mixed at 600 rpm for 10 minutes using a high-speed mixer. The mixture is then fed into a twin-screw extruder, and the temperature in the melt blending zone is controlled at 190-230℃. After melt blending, extrusion, cooling, and granulation, flame-retardant ABS material is obtained.

[0035] Example 2: Preparation of flame-retardant ABS material for automobiles. The specific implementation process is as follows:

[0036] 1) Preparation of composite flame retardants

[0037] Step A1: Undecenol and anhydrous tetrahydrofuran were mixed and stirred. Dry nitrogen gas was introduced until a stable gas flow was observed. The mixture was cooled to below 5°C using an ice-water bath. Methyldodecyl dichlorosilane was then slowly added and stirred for 3 hours. After the addition was complete, the ice-water bath was removed. Once the temperature returned to room temperature, a small amount of triethylamine was added and the reaction was continued with stirring for 0.5 hours. The reactants used in the reaction were: 0.1 mol methyldodecyl dichlorosilane, 0.2 mol undecenol, 30 mol% triethylamine of undecenol, and 200 mL anhydrous tetrahydrofuran. After the reaction was completed, the triethylamine salt was removed by filtration, and the tetrahydrofuran was recovered by rotary evaporation to obtain the modified monomer.

[0038] Step A2: Under dry nitrogen protection, the modified monomer, hypophosphite, and anhydrous toluene were mixed and stirred. The water bath temperature was controlled at 80℃. Benzoyl peroxide was added in three portions, intermittently over 2 hours, for a total reaction time of 8 hours. The amounts of raw materials used in the reaction were: 0.1 mol of modified monomer, 75 mmol of hypophosphite, 0.9 wt% of the total amount of benzoyl peroxide, and 350 mL of anhydrous toluene. After the reaction was completed, the toluene was recovered by rotary evaporation under reduced pressure to obtain the modified matrix.

[0039] Step A3: Take the modified matrix, 4-dimethylaminopyridine and anhydrous dioxane and stir to mix. Heat to 90℃ and slowly add γ-glycidoxypropyltrimethoxysilane and stir to react for 5h. The amount of raw materials used in the reaction is: 50g modified matrix, 15mmol γ-glycidoxypropyltrimethoxysilane, 0.5wt% of the total amount of 4-dimethylaminopyridine, and 250mL anhydrous dioxane. After the reaction is completed, dioxane is recovered by rotary evaporation under reduced pressure to obtain the phosphorus-silicon modifier.

[0040] Step A4: Take magnesium hydroxide micro powder and water and ultrasonically disperse to prepare a dispersion with a solid content of 15wt%. Dissolve the phosphorus-silicon modifier in dimethylacetamide and add the solution to the dispersion and stir for 24h. The raw materials used in the reaction are: 100g magnesium hydroxide micro powder, YTM-5 type micro powder with an average particle size of 5μm, and 15g phosphorus-silicon modifier. Centrifuge to separate the bottom precipitate and dry it to obtain the composite flame retardant.

[0041] 2) Preparation of flame-retardant ABS

[0042] Raw materials are prepared by weight as follows: 100 parts of ABS resin, XR404-9001 type resin raw material; 25 parts of composite flame retardant, prepared in this embodiment; 10 parts of toughening agent, M-701 type MBS (methyl methacrylate-butadiene-styrene) toughening agent; 0.5 parts of antioxidant, which is a mixture of antioxidant 1076 and antioxidant 168 in equal weight ratio; 1.5 parts of lubricant, ethylene bis-stearamide.

[0043] The above raw materials are mixed at 600 rpm for 10 minutes using a high-speed mixer. The mixture is then fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated at a processing temperature range of 190-230℃ to obtain flame-retardant ABS material.

[0044] Example 3: Preparation of flame-retardant ABS material for automobiles. The specific implementation process is as follows:

[0045] 1) Preparation of composite flame retardants

[0046] Step A1: Undecenol and anhydrous tetrahydrofuran were mixed and stirred. Dry nitrogen gas was introduced until a stable gas flow was observed. The mixture was cooled to below 5°C using an ice-water bath. Dioctyldichlorosilane was slowly added and stirred for 2 hours. After the addition was complete, the ice-water bath was removed. The mixture was allowed to return to room temperature, and a small amount of triethylamine was added and the mixture was stirred for another 1 hour. The reactants used in the reaction were: 0.1 mol dioctyldichlorosilane, 0.2 mol undecenol, 40 mol% triethylamine of undecenol, and 250 mL anhydrous tetrahydrofuran. After the reaction was completed, the triethylamine salt was removed by filtration, and the tetrahydrofuran was recovered by rotary evaporation to obtain the modified monomer.

[0047] Step A2: Under dry nitrogen protection, the modified monomer, hypophosphite, and anhydrous toluene were stirred and mixed. The water bath temperature was controlled at 70℃. Benzoyl peroxide was added in three portions, intermittently over 2 hours, for a total reaction time of 9 hours. The amounts of raw materials used in the reaction were: 0.1 mol of modified monomer, 80 mmol of hypophosphite, 1 wt% of the total amount of benzoyl peroxide, and 400 mL of anhydrous toluene. After the reaction was completed, the toluene was recovered by rotary evaporation under reduced pressure to obtain the modified matrix.

[0048] Step A3: Take the modified matrix, 4-dimethylaminopyridine and anhydrous dioxane and stir to mix. Heat to 90℃ and slowly add γ-glycidoxypropyltrimethoxysilane and stir to react for 5-7 hours. The amount of raw materials used in the reaction is: 50g modified matrix, 18mmol γ-glycidoxypropyltrimethoxysilane, 0.7wt% of the total amount of 4-dimethylaminopyridine, and 300mL anhydrous dioxane. After the reaction is completed, dioxane is recovered by rotary evaporation under reduced pressure to obtain the phosphorus-silicon modifier.

[0049] Step A4: Take magnesium hydroxide micro powder and water and ultrasonically disperse to prepare a dispersion with a solid content of 12wt%. Dissolve the phosphorus-silicon modifier in dimethylacetamide and add the solution to the dispersion and stir for 24h. The raw materials used in the reaction are: 100g magnesium hydroxide micro powder, YTM-3 type micro powder with an average particle size of 3μm, and 20g phosphorus-silicon modifier. Centrifuge to separate the bottom precipitate and dry it to obtain the composite flame retardant.

[0050] 2) Preparation of flame-retardant ABS

[0051] Raw materials are prepared by weight as follows: 100 parts of ABS resin, XR404-9001 type resin raw material; 20 parts of composite flame retardant, prepared in this embodiment; 13 parts of toughening agent, M-701 type MBS (methyl methacrylate-butadiene-styrene) toughening agent; 0.6 parts of antioxidant, which is a mixture of antioxidant 1076 and antioxidant 168 in equal weight ratio; 1.8 parts of lubricant, ethylene bis-stearamide.

[0052] The above raw materials are mixed at 600 rpm for 10 minutes using a high-speed mixer. The mixture is then fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated at a processing temperature range of 190-230℃ to obtain flame-retardant ABS material.

[0053] Comparative Example 1: ABS was modified with magnesium hydroxide and phosphosilicon flame retardant. The specific implementation process was the same as in Example 3, except that the composite flame retardant was replaced with 15 parts of magnesium hydroxide micro powder (YTM-3) and 5 parts of FO-2014S flame retardant; the rest were the same.

[0054] Comparative Example 2: A coupled phosphosilicone flame retardant was prepared according to existing technology and loaded onto the surface of magnesium hydroxide for flame retardant modification of ABS. The specific implementation method is as follows:

[0055] DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), triphenylphosphine, and anhydrous dimethylformamide were mixed and added under a dry nitrogen atmosphere. The mixture was then heated to 120°C and stirred for 6 hours. The reactants used in the reaction were: 0.1 mol DOPO, 0.1 mol γ-glycidyloxypropyltrimethoxysilane, 1.2 g triphenylphosphine, and 300 mL dimethylformamide. After the reaction was completed, the dimethylformamide was recovered by rotary evaporation under reduced pressure to obtain a coupled phosphorus-silicon flame retardant.

[0056] Referring to step A4 of Example 3, the coupling type phosphorus-silicon flame retardant is used to replace the phosphorus-silicon modifier in an equal amount, and the rest is the same.

[0057] The flame-retardant ABS material prepared above was tested for melt flow index according to GB / T 3682.1-2018 at a temperature of 220℃ and a load of 10kg. The same flame-retardant ABS material was then hot-pressed at 220℃ and 10MPa to form 1.6mm thick sheet samples. Flame retardancy rating was tested according to UL94 standard, limiting oxygen index according to GB / T 2406.2-2009 standard, and tensile strength according to GB / T 1040.2-2022 standard. Specific test results are shown in Table 1.

[0058] Table 1

[0059]

[0060] Based on the test data in Table 1, the flame-retardant ABS prepared in the examples all achieved a flame retardancy rating of V-0, with a limiting oxygen index of 30.5-31.2%, exhibiting good flame retardancy. The melt flow index was 9.2-10.5 g / 10 min, and the tensile strength was 44.7-48.5 MPa. Compared with the comparative example, it has better processability and higher mechanical strength.

[0061] The prepared sheet samples were subjected to a sustained flame retardancy test, specifically including: using a thermogravimetric analyzer, heating the sample from room temperature to 700℃ at a rate of 10℃ / min under a nitrogen atmosphere, and determining the residual mass percentage (char rate) at 700℃. An alcohol burner was used, held 10cm from the sample surface and moved back and forth at a rate of 1cm / s to simulate the ignition state of a flickering flame in an actual fire. After treatment, the sample was allowed to stand for 30min, and the tensile strength was measured. The tensile strength was compared with the initial tensile strength of the untreated sample in Table 1 to calculate the strength retention rate, denoted as R. n , where n is the number of repetitions. Specific test data is shown in Table 2:

[0062] Table 2

[0063]

[0064] Based on the test data in Table 2, at a high temperature of 700℃, the residual char rate of the flame-retardant ABS prepared in the examples was 28.9-31.1%, which was higher than that of the comparative examples. This indicates that the ABS material of the examples had better char formation at high temperatures. Under dynamic flame ignition, after 20 cycles of ignition, the tensile strength retention rate of the examples was 68.8-73.3%, while that of comparative example 1 was only 12.5% ​​and that of comparative example 2 was 39.2%. This shows that although the ABS material of the comparative examples did not burn under ignition, its mechanical properties were severely deteriorated, and it lost its load-bearing and protective capabilities.

[0065] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A flame-retardant ABS material for automobiles, characterized in that, It comprises the following components by weight: 100 parts ABS resin, 20-30 parts composite flame retardant, 10-15 parts toughening agent, 0.4-0.6 parts antioxidant, and 1.2-1.8 parts lubricant; The composite flame retardant is prepared by the following method: Step A1: Disperse undecenol in anhydrous tetrahydrofuran, continuously purge with dry nitrogen, cool in an ice-water bath, slowly add long-chain alkyl dichlorosilane and stir for 2-3 hours, then raise to room temperature and add triethylamine to continue the reaction for 0.5-1 hours to prepare the modified monomer. Step A2: Under dry nitrogen protection, the modified monomer and hypophosphite are dispersed in anhydrous toluene, and the water bath temperature is controlled at 65-80℃. Benzoyl peroxide is added intermittently and the mixture is stirred for 8-10 hours to prepare the modified matrix. Step A3: Mix the modified matrix, 4-dimethylaminopyridine and anhydrous dioxane, heat to 80-90℃, slowly add γ-glycidyl etheroxypropyltrimethoxysilane and stir for 5-7 hours to prepare a phosphorus-silicon modifier. Step A4: Disperse magnesium hydroxide micro powder in water using ultrasonication. Dissolve phosphorus-silicon modifier in dimethylacetamide and add it to the dispersion. Stir for 24 hours, centrifuge to separate the precipitate, and dry to obtain the composite flame retardant.

2. The flame-retardant ABS material for automobiles according to claim 1, characterized in that, The molar ratio of long-chain alkyl dichlorosilane to undecenol is 1:2, and the amount of triethylamine used is 30-40 mol of undecenol.

3. The flame-retardant ABS material for automobiles according to claim 2, characterized in that, The long-chain alkyl dichlorosilane is one of dioctyl dichlorosilane and methyl dodecyl dichlorosilane.

4. The flame-retardant ABS material for automobiles according to claim 3, characterized in that, The molar ratio of the modified monomer to hypophosphorous acid is 1:0.75-0.82, and the amount of benzoyl peroxide is 0.9-1.2 wt% of the total amount of both.

5. The flame-retardant ABS material for automobiles according to claim 4, characterized in that, The ratio of the modified matrix to γ-glycidoxypropyltrimethoxysilane is 100g:30-40mmol, and 4-dimethylaminopyridine is 0.5-0.8wt% of the total amount of both.

6. The flame-retardant ABS material for automobiles according to claim 5, characterized in that, The mass ratio of magnesium hydroxide micro powder to phosphorus-silicon modifier is 100:15-22.

7. The flame-retardant ABS material for automobiles according to claim 6, characterized in that, The average particle size of magnesium hydroxide powder is no higher than 10 μm.

8. A method for preparing a flame-retardant ABS material for automobiles according to any one of claims 1-7, characterized in that, Specifically, the components are mixed evenly, and the mixture is melt-blended, extruded, cooled, and granulated using a twin-screw extruder to obtain flame-retardant ABS material.

9. The method for preparing a flame-retardant ABS material for automobiles according to claim 8, characterized in that, The melt blending temperature range of a twin-screw extruder is 190-230℃.

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