An ABS composite containing a halogen-free flame retardant and a preparation process

Abstract

The present invention belongs to the technical field of ABS, and in particular relates to an ABS composite material containing a halogen-free flame retardant and a preparation process, which includes 100 parts by weight of ABS resin, 2-15 parts by weight of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and 0.3-2.5 parts by weight of compatibilizer. The poly(hydroxy DOPO-benzimidazole) halogen-free flame retardant of the present invention forms an intumescent flame retardant system. During combustion, the flame retardant generates phosphoric acid substances and non-combustible gases such as nitrogen, forming an intumescent foam carbon layer on the matrix and surface of the ABS material, which can block heat conduction, inhibit the contact between oxygen and the ABS matrix, and improve the flame retardancy of the ABS material. Using maleic anhydride grafted ABS or styrene-maleic anhydride copolymer as a compatibilizer improves the compatibility between the flame retardant and ABS, does not affect the mechanical properties of ABS, and can maintain good tensile strength and elongation at break.

Description

Technical Field

[0001] The present invention belongs to the technical field of ABS, and in particular relates to an ABS composite containing a halogen-free flame retardant and a preparation process. Background Art

[0002] Acrylonitrile-butadiene-styrene copolymer (ABS) has good mechanical properties, strong corrosion resistance, and excellent processing performance, and is widely used in medical devices, instruments, packaging materials, etc. However, the flame retardant performance of ABS resin is not good. In practical applications, when the ABS material encounters an open flame, it is easy to burn and cause a fire, which limits the practical application of ABS in the field of fire prevention and flame retardancy. Currently, mainly flame retardants are added to ABS to improve its fire resistance and flame retardancy effect.

[0003] Flame retardants mainly include phosphorus-based flame retardants, intumescent flame retardants, brominated halogen-containing flame retardants, etc. In recent years, the development of environmentally friendly halogen-free flame retardants is a research trend. Compared with small molecule flame retardants, macromolecular polymer flame retardants have good high-temperature resistance, are not easily thermally decomposed during the processing process, have excellent flame retardant effects, and have broad application prospects in polymer materials. Chinese Patent CN116694018B discloses a halogen-free flame retardant modified ABS plastic and its synthesis process, using a nitrogen-phosphorus styrene-acrylonitrile copolymer as a halogen-free flame retardant and maleic anhydride grafted ABS as a compatibilizer, which can improve the compatibility between the flame retardant and the ABS plastic matrix, thereby improving the flame retardant performance, tensile strength, and impact strength of the material. Therefore, the development of new polymer-based flame retardants is an effective method to improve the flame retardant and other properties of ABS materials. Summary of the Invention

[0004] The present invention solves the problems of poor flame retardancy of ABS, poor compatibility between nitrogen-phosphorus-based halogen-free flame retardants and ABS, and great influence on its mechanical properties.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: an ABS composite containing a halogen-free flame retardant, comprising 100 parts by weight of ABS resin, 2 - 15 parts by weight of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and 0.3 - 2.5 parts by weight of compatibilizer.

[0006] Preferably, the preparation process of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant is as follows:

[0007] Add 3,6-dibromobenzimidazole-hydroxy DOPO, 1,4-phenylenediboronic acid, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide, potassium carbonate, water into a reaction flask equipped with a condenser reflux tube, displace the air by introducing nitrogen, carry out a coupling polymerization reaction, add water to dilute the solution, filter the solvent, wash with water and ethanol in sequence, and dry to obtain poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant.

[0008] Preferably, the compatibilizer is a styrene-maleic anhydride copolymer or maleic anhydride grafted ABS.

[0009] Preferably, the molar ratio of 3,6-dibromobenzimidazole-hydroxy DOPO, 1,4-benzenediboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate is 1:(0.95 - 1.05):(0.01 - 0.013):(1.5 - 1.8).

[0010] Preferably, the volume ratio of N,N-dimethylformamide to water is 1:(0.08 - 0.1).

[0011] Preferably, the coupling polymerization reaction is carried out at a temperature of 85 - 100 °C for 24 - 48 h.

[0012] Preferably, the preparation process of 3,6-dibromobenzimidazole-hydroxy DOPO is as follows: Add N,N-dimethylformamide, 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde with a molar ratio of 1:(1.1 - 1.3):(1.1 - 1.3), 3,6-dibromo-1,2-benzenediamine, and sodium bisulfite into a reaction flask equipped with a condenser reflux tube. Replace the air with nitrogen, carry out a cyclization reaction at 120 - 135 °C for 12 - 24 h, add water for dilution, then add dichloromethane for extraction, combine the organic phases, dry with anhydrous sodium sulfate, distill the filtrate under reduced pressure, and then carry out silica gel column chromatography separation to obtain 3,6-dibromobenzimidazole-hydroxy DOPO.

[0013] Preferably, the preparation process of the halogen-free flame retardant-containing ABS composite material is as follows: Melt and blend ABS resin, poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and compatibilizer in a twin-screw extruder. The temperature of the 1st - 6th sections of the extruder is 170 - 200 °C, and the screw speed is 30 - 60 r / min; After extrusion, pelletize with a pelletizer to obtain the halogen-free flame retardant-containing ABS composite material.

[0014] Technical effect: The present invention utilizes the Suzuki coupling reaction of 3,6-dibromobenzimidazole-hydroxy DOPO and 1,4-benzenediboronic acid to obtain a novel halogen-free flame retardant based on a polymer containing hydroxyl groups, namely poly(hydroxy DOPO-benzimidazole). Further, using styrene-maleic anhydride copolymer or maleic anhydride-grafted ABS as a compatibilizer, ABS is blended and modified. The halogen-free flame retardant contains a DOPO structure, which can serve as an acid source, and the imidazole structure serves as a nitrogen-containing gas source. The main chain contains a polyaromatic ring structure with a high carbon content and has high char-forming ability, which can serve as a carbon source to form an intumescent flame retardant system. During combustion, the flame retardant generates phosphoric acid substances and non-combustible gases such as nitrogen, forming an intumescent foam carbon layer on the matrix and surface of the ABS material, which can block heat conduction and inhibit the contact of oxygen with the ABS matrix, thereby endowing the ABS material with excellent flame retardancy. Moreover, the polyaromatic ring structure with high heat resistance in the main chain of the added halogen-free flame retardant has a certain promoting effect on the thermal decomposition temperature and heat resistance of ABS.

[0015] In the present invention, maleic anhydride-grafted ABS or styrene-maleic anhydride copolymer is used as a compatibilizer, which contains maleic anhydride groups and can react with the hydroxyl groups in the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO). Thus, the compatibilizer plays a role in compatibilizing the halogen-free flame retardant and ABS, improving the compatibility between the two, preventing the halogen-free flame retardant from affecting the mechanical properties of ABS, and maintaining good tensile strength and elongation at break. Specific embodiments

[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further elaborates on the present invention in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Those skilled in the art who make modifications or equivalent substitutions on the basis of understanding the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall all be covered within the protection scope of the present invention.

[0017] Prepared according to the method in the journal "Journal of Xihua University (Natural Science Edition)", Vol. 34, No. 6, November 2015, "Synthesis and Characterization of 4-[(6-Oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde": Add 0.5 mol of terephthalaldehyde to a reaction flask, and dropwise add 15 mL of a 1,4-dioxane solution containing 0.55 mmol of DOPO at 30°C. React for 7 h, cool and then filter by suction, and recrystallize with ethanol to obtain 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde. The structural formula is:

[0018] The CAS number of DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) of the present invention is 35948-25-5. The CAS number of 3,6-dibromo-1,2-phenylenediamine is 69272-50-0.

[0019] ABS resin grade GP-35, Shenghao Plastics, Dongguan.

[0020] Maleic anhydride grafted ABS model SH002, Shenghao Plastics, Dongguan.

[0021] Styrene-maleic anhydride copolymer model Polyscope XIRAN 4000, Yingqun Chemical Industry, Shenzhen.

[0022] Example 1

[0023] Add 200 mL of N,N-dimethylformamide, 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde with a molar ratio of 60 mmol, 78 mmol of 3,6-dibromo-1,2-phenylenediamine, and 78 mmol of sodium bisulfite into a reaction flask equipped with a condenser reflux tube. Pass nitrogen to displace air, heat up to 120 °C, carry out cyclization reaction for 12 h, add water for dilution, then add dichloromethane for extraction, combine the organic phases, dry with anhydrous sodium sulfate, distill the filtrate under reduced pressure, and then carry out silica gel column chromatography separation. The eluent is a petroleum ether and ethyl acetate solution with a volume ratio of 3:1 to obtain 3,6-dibromobenzimidazole-hydroxy DOPO. The yield is 20.62 g, a pale yellow powder. The reaction formula is as follows:

[0024]

[0025] Add 40 mmol of 3,6-dibromobenzimidazole-hydroxy DOPO, 38 mmol of 1,4-phenylenediboronic acid, 0.4 mmol of tetrakis(triphenylphosphine)palladium, 1500 mL of N,N-dimethylformamide, 72 mmol of potassium carbonate, 150 mL of water into a reaction flask equipped with a condenser reflux tube. Pass nitrogen to displace air, heat to 100 °C, carry out coupling polymerization reaction for 24 h, add water for dilution to the solution, filter the solvent, wash successively with water and ethanol, and dry to obtain poly(hydroxy DOPO-benzimidazole) halogen-free flame retardant. The yield is 11.25 g, a yellow powder. The reaction formula is:

[0026]

[0027] 1000 g of ABS resin, 20 g of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and 3 g of compatibilizer maleic anhydride grafted ABS were melt-blended in a twin-screw extruder. The temperatures of the 1st to 6th sections of the extruder were 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed was 40 r / min. After extrusion, it was pelletized by a pelletizer to obtain an ABS composite containing a halogen-free flame retardant.

[0028] Example 2

[0029] 150 mL of N,N-dimethylformamide, 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde with a molar ratio of 60 mmol, 66 mmol of 3,6-dibromo-1,2-phenylenediamine, and 66 mmol of sodium bisulfite were added to a reaction flask equipped with a condenser reflux tube. Nitrogen was introduced to displace air, and the temperature was raised to 135 °C for a cyclization reaction for 18 h. Water was added for dilution, and then dichloromethane was added for extraction. The organic phases were combined, dried over anhydrous sodium sulfate, and the filtrate was distilled under reduced pressure. Then, silica gel column chromatography separation was carried out, and the eluent was a petroleum ether and ethyl acetate solution with a volume ratio of 3:1 to obtain 3,6-dibromobenzimidazole-hydroxy DOPO. The yield was 22.19 g, a pale yellow powder.

[0030] 40 mmol of 3,6-dibromobenzimidazole-hydroxy DOPO, 42 mmol of 1,4-benzenediboronic acid, 0.42 mmol of tetrakis(triphenylphosphine)palladium, 1500 mL of N,N-dimethylformamide, 66 mmol of potassium carbonate, 130 mL of water were added to a reaction flask equipped with a condenser reflux tube. Nitrogen was introduced to displace air, and it was heated to 90 °C for a coupling polymerization reaction for 36 h. Water was added to the solution for dilution, the solvent was filtered, and it was washed successively with water and ethanol and then dried to obtain a poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant. The yield was 12.46 g, a yellow powder.

[0031] 1000 g of ABS resin, 60 g of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and 9 g of compatibilizer styrene-maleic anhydride copolymer were melt-blended in a twin-screw extruder. The temperatures of the 1st to 6th sections of the extruder were 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed was 30 r / min. After extrusion, it was pelletized by a pelletizer to obtain an ABS composite containing a halogen-free flame retardant.

[0032] Example 3

[0033] Add 200 mL of N,N-dimethylformamide, 4-[(6-oxo-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde with a molar ratio of 60 mmol, 72 mmol of 3,6-dibromo-1,2-phenylenediamine, and 78 mmol of sodium bisulfite into a reaction flask equipped with a condensation reflux tube. Purge the air with nitrogen, heat up to 120 °C, and carry out the cyclization reaction for 24 h. Add water for dilution, then extract with dichloromethane. Combine the organic phases, dry with anhydrous sodium sulfate, distill the filtrate under reduced pressure, and then carry out silica gel column chromatography separation. The eluent is a petroleum ether and ethyl acetate solution with a volume ratio of 3:1 to obtain 3,6-dibromobenzimidazole-hydroxy DOPO. The yield is 20.14 g, a pale yellow powder.

[0034] Add 40 mmol of 3,6-dibromobenzimidazole-hydroxy DOPO, 40 mmol of 1,4-phenylenediboronic acid, 0.42 mmol of tetrakis(triphenylphosphine)palladium, 1500 mL of N,N-dimethylformamide, 60 mmol of potassium carbonate, and 150 mL of water into a reaction flask equipped with a condensation reflux tube. Purge the air with nitrogen, heat to 85 °C, and carry out the coupling polymerization reaction for 48 h. Add water for dilution to the solution, filter the solvent, wash successively with water and ethanol, and dry to obtain the halogen-free flame retardant poly(hydroxy DOPO-benzimidazole). The yield is 12.05 g, a yellow powder.

[0035] Melt and blend 1000 g of ABS resin, 100 g of the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO), and 16 g of the compatibilizer maleic anhydride grafted ABS in a twin-screw extruder. The temperatures of the 1st - 6th sections of the extruder are 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 60 r / min; pelletize after extrusion with a pelletizer to obtain the ABS composite containing the halogen-free flame retardant.

[0036] Example 4

[0037] Add 200 mL of N,N-dimethylformamide, 4-[(6-oxo-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde with a molar ratio of 60 mmol, 72 mmol of 3,6-dibromo-1,2-phenylenediamine, and 72 mmol of sodium bisulfite into a reaction flask equipped with a condensation reflux tube. Purge the air with nitrogen, heat up to 125 °C, and carry out the cyclization reaction for 18 h. Add water for dilution, then extract with dichloromethane. Combine the organic phases, dry with anhydrous sodium sulfate, distill the filtrate under reduced pressure, and then carry out silica gel column chromatography separation to obtain 3,6-dibromobenzimidazole-hydroxy DOPO. The yield is 21.58 g, a pale yellow powder.

[0038] Add 40 mmol of 3,6-dibromobenzimidazole-hydroxy DOPO, 40 mmol of 1,4-benzenediboronic acid, 0.42 mmol of tetrakis(triphenylphosphine)palladium, 1500 mL of N,N-dimethylformamide, 68 mmol of potassium carbonate, and 120 mL of water into a reaction flask equipped with a condensation reflux tube. Replace the air with nitrogen, heat to 85 °C, and carry out the coupling polymerization reaction for 36 h. Add water to dilute the solution, filter the solvent, wash successively with water and ethanol, and dry to obtain the halogen-free flame retardant poly(hydroxy DOPO-benzimidazole). The yield is 11.90 g, and it is a yellow powder.

[0039] Put 1000 g of ABS resin, 150 g of the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO), and 25 g of the compatibilizer maleic anhydride-grafted ABS into a twin-screw extruder for melt blending. The temperatures of the 1st - 6th sections of the extruder are 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 60 r / min. After extrusion, pelletize with a pelletizer to obtain the ABS composite containing the halogen-free flame retardant.

[0040] Comparative Example 1

[0041] The difference between this comparative example and Example 1 is that the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO) is not added.

[0042] Put 1000 g of ABS resin and 3 g of the compatibilizer maleic anhydride-grafted ABS into a twin-screw extruder for melt blending. The temperatures of the 1st - 6th sections of the extruder are 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 40 r / min. After extrusion, pelletize with a pelletizer to obtain the ABS composite containing the halogen-free flame retardant.

[0043] Comparative Example 2

[0044] The difference between this comparative example and Example 1 is that the compatibilizer maleic anhydride-grafted ABS is not added.

[0045] Put 1000 g of ABS resin and 20 g of the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO) into a twin-screw extruder for melt blending. The temperatures of the 1st - 6th sections of the extruder are 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 40 r / min. After extrusion, pelletize with a pelletizer to obtain the ABS composite containing the halogen-free flame retardant.

[0046] Comparative Example 3

[0047] The difference between this comparative example and Example 1 is that 3,6-dibromobenzimidazole-hydroxy DOPO is used to replace the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO).

[0048] 1000 g of ABS resin, 20 g of 3,6-dibromobenzimidazole-hydroxy DOPO, and 3 g of compatibilizer maleic anhydride grafted ABS were melt blended in a twin-screw extruder. The temperatures of the 1st to 6th sections of the extruder were 170 °C, 185 °C, 190 °C, 200 °C, 200 °C, and 195 °C, and the screw speed was 40 r / min. After extrusion, the pellets were obtained by a pelletizer to prepare an ABS composite containing a halogen-free flame retardant.

[0049] The ABS composite containing a halogen-free flame retardant was made into standard specimens by an injection molding machine. The limiting oxygen index of the specimens was tested according to the method of GB / T 2406.1-2008. The vertical burning performance of the specimens was tested according to the UL94 method. The tensile properties of the specimens were tested according to the method of GB / T 1040.1-2018.

[0050] The specimens were placed in a thermogravimetric analyzer, and under a nitrogen atmosphere, they were heated from 30 °C to 700 °C at a heating rate of 10 °C / min for thermogravimetric performance testing.

[0051] Table 1 Performance Testing of ABS Composite

[0052]

[0053]

[0054] As can be seen from Table 1, no flame retardant was added to the ABS in Comparative Example 1. The limiting oxygen index was 18.9%, there was no rating in UL94, and the char residue was only 1.20%, indicating very poor flame retardant performance. The tensile strength was 40.2% and the elongation at break was 18.6%.

[0055] In each example, a halogen-free flame retardant of poly(benzimidazole-hydroxy DOPO), and a compatibilizer of maleic anhydride grafted ABS or styrene-maleic anhydride copolymer were added. The halogen-free flame retardant contains a DOPO structure, which can act as an acid source, and the imidazole structure acts as a nitrogen-containing gas source. The main chain contains a polyaromatic ring structure with heat resistance and high carbon content. It has high char-forming ability and acts as a carbon source to form an intumescent flame retardant system. During combustion, phosphoric acid substances and non-combustible gases such as nitrogen are generated, and an intumescent foam carbon layer is formed on the matrix and surface of the ABS material, which can block heat conduction and inhibit the contact of oxygen with the ABS matrix, so that the ABS material has excellent flame retardant properties. UL94 reaches V1 to V0 grades, and the limiting oxygen index reaches 27.8 - 31.5%. And the polyaromatic ring structure with heat resistance of the main chain of the added halogen-free flame retardant has a certain improvement effect on the heat resistance of ABS, and the thermal decomposition temperature (temperature at 5% mass loss) reaches 384.8 - 389.1 °C, which is higher than that of Comparative Example 1.

[0056] And maleic anhydride grafted ABS or styrene-maleic anhydride copolymer is added as a compatibilizer, which contains maleic anhydride groups and can react with the hydroxyl groups in the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO), so that the compatibilizer plays the role of compatibilizing the halogen-free flame retardant and ABS, improving the compatibility between the two, and preventing the halogen-free flame retardant from affecting the mechanical properties of ABS. The tensile strength is maintained at 37.8-42.0 MPa, and the elongation at break is maintained at 17.8-19.2%, which is very similar to the ABS material of Comparative Example 1.

[0057] The limiting oxygen index of the ABS material in Comparative Example 2 also reaches 27.6%, which is higher than that in Comparative Example 1, and the flame retardancy is excellent. However, the compatibilizer maleic anhydride grafted ABS is not added, and the compatibility between the halogen-free flame retardant and the ABS resin matrix is very poor, which will affect the mechanical properties of the material. The tensile strength is only 35.8 MPa, and the elongation at break is 14.7%, which is significantly lower than that in Comparative Example 1.

[0058] In Comparative Example 3, 3,6-dibromobenzimidazole-hydroxy DOPO is used as the flame retardant. The flame retardant contains DOPO and imidazole structures, which can form a nitrogen-phosphorus flame retardant and also contains bromine flame retardant elements, improving the limiting oxygen index and flame retardant performance of the ABS material. And the flame retardant contains hydroxyl groups, which can react with the anhydride groups of the compatibilizer, and the compatibility between the flame retardant and the ABS resin matrix is also very good, with little impact on the tensile properties of the ABS material. However, this flame retardant does not contain a polyaromatic ring structure, and its char-forming performance is lower than that of the halogen-free flame retardant poly(benzimidazole-hydroxy DOPO). The high-temperature residual carbon content of the ABS material is 7.65%, which is lower than that of each example. And the flame retardant contains bromine flame retardant elements, generating bromine-containing substances such as hydrogen bromide during combustion, resulting in relatively large pollution.

[0059] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An ABS composite containing a halogen-free flame retardant, characterized in that, The described ABS composite material comprises 100 parts by weight of ABS resin, 2 - 15 parts by weight of poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and 0.3 - 2.5 parts by weight of compatibilizer; The preparation process of the poly(hydroxy DOPO-benzimidazole) halogen-free flame retardant is as follows: Add 3,6-dibromobenzimidazole-hydroxy DOPO, 1,4-phenylenediboronic acid, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide, potassium carbonate, water into a reaction flask equipped with a condensing reflux tube, displace the air by introducing nitrogen, carry out a coupling polymerization reaction, dilute the solution with water, filter the solvent, wash, and dry to obtain the poly(hydroxy DOPO-benzimidazole) halogen-free flame retardant; The 3,6-dibromobenzimidazole-hydroxy DOPO has a structural formula shown in formula (1):

2. The halogen-free flame retardant-containing ABS composite material according to claim 1, wherein The compatibilizer is a styrene-maleic anhydride copolymer or maleic anhydride grafted ABS.

3. The halogen-free flame retardant-containing ABS composite material according to claim 1, characterized in that The molar ratio of the 3,6-dibromobenzimidazole-hydroxy DOPO, 1,4-phenylenediboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate is 1:(0.95 - 1.05):(0.01 - 0.013):(1.5 - 1.8).

4. The halogen-free flame retardant-containing ABS composite material according to claim 1, wherein The volume ratio of the N,N-dimethylformamide to water is 1:(0.08 - 0.1).

5. The ABS composite material containing a halogen-free flame retardant according to claim 1, characterized in that, The coupling polymerization reaction is carried out at a temperature of 85 - 100 °C for 24 - 48 h.

6. The halogen-free flame retardant-containing ABS composite material according to claim 3, characterized in that, The preparation process of the 3,6-dibromobenzimidazole-hydroxy DOPO is as follows: Add N,N-dimethylformamide, 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde, 3,6-dibromo-1,2-phenylenediamine, and sodium bisulfite into a reaction flask equipped with a condensing reflux tube, displace the air by introducing nitrogen, carry out a cyclization reaction, extract, and separate by silica gel column chromatography to obtain 3,6-dibromobenzimidazole-hydroxy DOPO.

7. The halogen-free flame retardant-containing ABS composite material according to claim 6, wherein The molar ratio of the 4-[(6-oxo-6H-dibenzo(c,e)(1,2)oxaphosphorin-6-yl)hydroxymethyl]benzaldehyde, 3,6-dibromo-1,2-phenylenediamine, and sodium bisulfite is 1:(1.1 - 1.3):(1.1 - 1.3).

8. The halogen-free flame retardant-containing ABS composite material according to claim 6, wherein, The cyclization reaction is carried out at 120 - 135 °C for 12 - 24 h.

9. The preparation process of an ABS composite material containing a halogen-free flame retardant as described in any one of claims 1-8, characterized in that, The preparation process is as follows: Mix the ABS resin, poly(benzimidazole-hydroxy DOPO) halogen-free flame retardant, and compatibilizer in a twin-screw extruder by melt blending. The temperature of the 1st - 6th sections of the extruder is 170 - 200 °C, and the screw speed is 30 - 60 r / min; After extrusion, pelletize with a pelletizer to obtain the ABS composite material containing the halogen-free flame retardant.

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