Preparation method of flame-retardant high-performance polypropylene and automobile foot mat prepared from flame-retardant high-performance polypropylene

Abstract

The invention relates to a preparation method of flame-retardant high-performance polypropylene and an automobile foot mat prepared from the same. The material comprises the following components in parts by weight: 100-120 parts of a polypropylene matrix; 9-12 parts of a flame retardant; 0.1 to 2.5 parts of an antioxidant; wherein the polypropylene matrix is a high-molecular polymer matrix with a net structure, which is obtained by cross-linking polypropylene with a first copolymer of polyacrylate and then cross-linking polypropylene with a segmented copolymer; the flame retardant is a hydrotalcite flame retardant with a self-crosslinking group, the flame retardant is controlled in a matrix under the action of positive and negative charges and crosslinking, the dispersing performance and compatibility of the flame retardant are remarkably improved, polypropylene is endowed with excellent flame retardant property, and the mechanical property of the material is greatly improved. According to the polypropylene composite material prepared by the technical scheme, the foot mat hardened at a low temperature still has good rigidity and toughness, is not easy to deform in a treading stress process, and can be used for manufacturing an automobile foot mat.

Description

Technical Field

[0001] The present invention relates to a polymer polypropylene composite material, belonging to the field of polymer flame-retardant plastics, and particularly relates to a preparation method of flame-retardant high-performance polypropylene. Background Art

[0002] As a general-purpose plastic, polypropylene has characteristics such as good processability, mechanical properties, and low price, and has a low specific gravity and light weight, and is widely used in various molded products such as films, sheets, and structural components. However, polypropylene also has disadvantages such as poor low-temperature toughness, insufficient high-temperature strength, and flammability, which greatly limit the application range of polypropylene materials. Therefore, high-performance modification such as reinforcement, toughening, and flame retardancy of polypropylene is a necessary means to broaden its application field.

[0003] Adding flame retardants can effectively reduce the combustion performance of polymers. Halogen-containing flame retardants can endow polypropylene products with good flame retardant properties. However, halogenated flame retardant products will generate a large amount of black smoke during combustion, and release hydrogen halide gas and some carcinogenic substances, which affect the environment and human health. Therefore, the application of halogen-containing flame retardants is greatly restricted, and some countries and organizations have prohibited the use of some halogen-containing flame retardants. In this environment, halogen-free flame retardants and halogen-free flame retardant products have been greatly developed and applied.

[0004] As a halogen-free flame retardant, the intumescent flame retardant mainly consists of salts of polyphosphoric acid or pyrophosphoric acid and nitrogen-containing compounds. It forms a surface expansion layer during combustion, inhibits the diffusion of decomposition products and heat transfer, and thus exerts flame retardancy. However, halogen-free flame retardants often need to be added in large amounts to the matrix resin to have good flame retardant effects. The mechanical properties of halogen-free flame retardant products are even much lower than those of the matrix resin, which will seriously affect the mechanical properties of the resin and thus damage the original physical properties of the resin. Polypropylene has poor antistatic properties, and after conventional flame retardant and antistatic modification, the mechanical properties of the product are significantly reduced. Therefore, the mechanical properties, wear resistance, and anti-aging properties of the finally obtained flame retardant and antistatic polypropylene are significantly reduced, which limits its service life.

[0005] For the reinforcement of mechanical properties, an improved method is to increase the melt strength of polypropylene, that is, to increase the molecular weight of polypropylene, but this will bring difficulties in material melting and extrusion. Another method is to broaden the molecular weight distribution. For example, US7365136 and US6875826 report a method for preparing polypropylene with a broad molecular weight distribution, high melt strength, homopolymerization, and random copolymerization. It selects alkoxysilane as an external electron donor (such as dicyclopentyldimethoxysilane), and adjusts the hydrogen concentration in multiple series reactors to control the molecular weight size and distribution, so as to achieve the effect of increasing the melt strength of polypropylene.

[0006] Alternatively, by improving the intumescent flame retardant, the compatibility between the flame retardant and the polypropylene matrix can be enhanced. Chinese Patent with Publication No. CN107915901A discloses a polypropylene environmentally friendly flame retardant foam material and its preparation method, which includes the following raw materials: diatomite, polypropylene, foaming agent, nano-TiO 2 , phosphorus-based intumescent flame retardant, carboxylated polypropylene, dicumyl peroxide, silane coupling agent, titanate coupling agent, zirconate coupling agent, stearic acid. The phosphorus-based intumescent flame retardant used is an environmentally friendly green flame retardant, whose system has a synergistic effect itself, has excellent flame retardant performance, and produces low smoke, low toxicity, and no corrosive gases. This method combines the flame retardant onto the main chain or side chain of polypropylene through chemical methods, making the modified polypropylene flame retardant and significantly improving its compatibility with the matrix. However, the preparation process is complex and the cost is relatively high.

[0007] Chinese Patent with Publication No. CN111040293B discloses an intumescent flame retardant polypropylene and its preparation method. This intumescent flame retardant polypropylene includes the following components in parts by mass: 70 - 100 parts of polypropylene, 10 - 30 parts of intumescent flame retardant, 1 - 5 parts of modified nano-silica, 0 - 0.2 parts of antioxidant; among them, the modified nano-silica is nano-silica grafted and modified with a triazine derivative containing phenyl and triazine groups. The preparation method of this intumescent flame retardant polypropylene includes the following steps: according to the ratio, mix polypropylene, intumescent flame retardant, modified nano-silica and antioxidant, and place the mixture in a reactor for melt blending to obtain. This modified nano-silica composite reinforced intumescent flame retardant polypropylene of the invention has excellent flame retardant performance. However, the intumescent flame retardants in the prior art still have problems such as poor water resistance, poor low-temperature toughness, and poor wear resistance.

[0008] Therefore, developing a polypropylene composite material with good thermal stability and polymer compatibility of each component, uniform dispersion of each component, not easy to precipitate, enabling the material to achieve long-term flame retardancy, having good low-temperature toughness, and excellent mechanical properties, wear-resistant and durable is the current research focus. Summary of the Invention

[0009] In order to solve the above problems, the purpose of the present invention is to provide a preparation method of flame-retardant high-performance polypropylene to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0010] The object of the present invention is achieved by the following technical solutions: A flame-retardant high-performance polypropylene material, which is prepared from the following raw materials in parts by mass: 100-120 parts of a polypropylene matrix; 9-12 parts of a flame retardant; 0.1-2.5 parts of an antioxidant; The polypropylene matrix is a first copolymer polymerized from acrylic acid monomers, a polymer matrix of a high molecular weight network structure obtained by crosslinked block copolymerization; The block copolymer is a styrene-butadiene-styrene block copolymer.

[0011] According to one aspect of the present invention, in order to achieve the above object, first, a polypropylene matrix with good low-temperature toughness and significantly improved elasticity is prepared, which specifically includes the following steps:

[0012] S001: In a reaction kettle, isooctyl acrylate, dimethylaminoethyl methacrylate, hydroxypropyl acrylate, and n-dodecyl mercaptan are stirred evenly. Under nitrogen protection, the temperature is slowly raised to 110-150 °C, and then the initiator azobisisobutyronitrile is added dropwise. After reacting for 150-200 minutes, acrylic acid is added and the reaction continues for 100-150 minutes to obtain a first copolymer with a high molecular weight of 50,000-60,000, and hydroxyl and amino groups are grafted on its side chains;

[0013] S002, adding the first copolymer and the block copolymer into the reaction kettle. Under nitrogen protection, the temperature is raised to 200-220 °C, and the stirring speed is 500 rpm. The block copolymer is dispersed in the high molecular weight first copolymer, and polypropylene is added, and the reaction continues for 60-80 minutes to obtain a polymer matrix of a high molecular weight network structure;

[0014] The mass fraction of the dimethylaminoethyl methacrylate is 50-60 parts, the mass fraction of the isooctyl acrylate is 10-20 parts, the mass fraction of the acrylic acid is 20-30 parts, the mass fraction of the hydroxypropyl acrylate is 50-60 parts, the mass fraction of the n-dodecyl mercaptan is 1.0-2.5 parts, and the mass fraction of the azobisisobutyronitrile is 2.0-4.0 parts;

[0015] The mass ratio of the block copolymer, the first copolymer, and polypropylene is 2-4:10:100; the molecular weight of the block copolymer is 60,000-70,000;

[0016] 100 parts of polypropylene matrix, 9 parts of flame retardant, and 0.5 part of antioxidant are melt-blended to obtain a kneaded product, which is flame-retardant polypropylene. We found that the flame-retardant polypropylene obtained in this way has improved low-temperature performance due to its polymer with a high-molecular network structure. The obtained matrix has good elasticity and is easy to recover after deformation, improving the problems that polypropylene becomes hard, brittle, and prone to fracture under low-temperature conditions. However, we found that when the first copolymer of styrene-butadiene-styrene block copolymer and polyacrylate is directly dispersed in polypropylene, it will be unevenly dispersed, and there will be problems such as poor thermal stability, poor aging resistance, and poor mechanical properties. The compatibility between the intumescent flame retardant and the matrix is insufficient, resulting in a series of problems such as precipitation.

[0017] Therefore, we modified the styrene-butadiene-styrene block copolymer, hoping to improve its compatibility with the flame retardant and the compatibility between polyacrylate and polypropylene on the basis of improving its mechanical properties. Specifically:

[0018] S101, Dissolve the styrene-butadiene-styrene block copolymer in ethyl acetate, stir evenly at a temperature of 60-70 °C, add maleic anhydride, stir to dissolve, then add the initiator benzoyl peroxide, and react for 12-14 hours under the protection of a nitrogen stream to obtain a grafted maleic anhydride block copolymer.

[0019] S102, Then, drop N,N-dimethylhexadecyl-1-amine and N,N-dimethylformamide into the solution of the grafted maleic anhydride block copolymer, and react at a temperature of 60-70 °C for 24-30 hours under the action of the dehydrating agent 4-dimethylaminopyridine. After the reaction is completed, filter the impurities in the mixed solution to obtain a clear and slightly viscous filtrate. Dry it in an oven at 35 °C and wash it with deionized water multiple times to obtain an aminated block copolymer; among them, the mass ratio of maleic anhydride to styrene-butadiene-styrene block copolymer is 1:2, and the mass of the initiator is 2% of the total mass of the styrene-butadiene-styrene block copolymer and maleic anhydride; the mass ratio of N,N-dimethylhexadecyl-1-amine to styrene-butadiene-styrene block copolymer is 1:10; the mass ratio of N,N-dimethylhexadecyl-1-amine to N,N-dimethylformamide is 1:2.

[0020] Due to the opposite polarity between polypropylene and intumescent flame retardant particles, the intumescent flame retardant has poor compatibility and uneven dispersion in polypropylene, resulting in easy agglomeration of the intumescent flame retardant and reduction of flame retardancy and mechanical properties. To avoid these drawbacks, the conventional intumescent flame retardant is compounded with a small amount of nanoparticles for use, which can simultaneously improve the flame retardancy and mechanical properties of polypropylene. These nano-additives can induce the formation of an inorganic-rich protective carbon layer, thereby improving flame retardancy and enhancing the mechanical properties of the material. However, a coupling agent is required to perform surface treatment on the nanoparticles to improve the dispersion of the nanoparticles in the polypropylene matrix. Since most organic coupling agents are highly flammable, the flame retardancy of the final material is not ideal enough.

[0021] The first copolymer contained in the polypropylene matrix has hydroxyl and amine groups grafted on its side chains. These small polar substances have the defect of poor dispersion in the non-polar polypropylene matrix. As the use time increases, the small polar carbon source molecules are prone to migrate to the material surface, resulting in uneven dispersion of the carbon source in the polypropylene matrix and a decrease in the flame retardancy of the material. Moreover, due to the poor compatibility between the small polar carbon source molecules and non-polar polypropylene, the mechanical properties of the polypropylene flame retardant material are further deteriorated. Therefore, we select an inorganic material with anions and negative charges as the flame retardant, so that the flame retardant interacts and restricts with these polar substances in the matrix, not only improving the compatibility between the flame retardant and the matrix, but also firmly controlling the flame retardant and small polar substances in the matrix through the action of positive and negative charges, making it not easy to precipitate.

[0022] Therefore, we have prepared a flame retardant that can effectively solve the problems of unsatisfactory dispersion and flame retardant effect, and can effectively solve the problem of precipitation of the flame retardant. The described flame retardant is a hydrotalcite flame retardant with self-crosslinking groups. This flame retardant has a unique nano-sheet structure and is an organic-inorganic hybrid material. It has a carbon source, an acid source and a gas source at the same time. Hydrotalcite is hydrophilic and there is also a problem of easy precipitation during use. Therefore, it is organically modified to improve its hydrophobic property and compatibility with polymers. The specific preparation method is as follows:

[0023] S201, dry the hydrotalcite at 80 °C for 5 hours, then place the hydrotalcite in an acid mixture of nitric acid and sodium nitrate, heat it to 90 °C, stir and soak for 2 hours. After the reaction is completed, filter by suction, wash it 3 times with absolute ethanol, and dry it at 80 °C for 20 hours to obtain a hydrotalcite with an expanded interlayer spacing. Then add glycine to the hydrotalcite with an expanded interlayer spacing, react at 60 - 80 °C for 24 hours to obtain a suspension. The volume ratio of nitric acid to sodium nitrate is 1:10, the concentration of nitric acid is 0.5 mol / L, and the concentration of sodium nitrate is 1.2 mol / L; the mass ratio of hydrotalcite to the mixture of nitric acid and sodium nitrate is 1:1; the mass ratio of glycine to hydrotalcite is 2 - 3:10;

[0024] S202. Add dodecyl phosphoric acid and inositol hexaphosphate to the suspension, stir and react at 60 - 80 °C for 6 - 8 hours to obtain a reaction solution; adjust the pH to neutral with citric acid, obtain the product using a rotary evaporator, place the product in an oven at 80 °C and dry for 12 hours to obtain a white solid with a large amount of anions in the interlayer; disperse the white solid in deionized water to obtain a dispersion; the mass ratio of dodecyl phosphoric acid, inositol hexaphosphate and hydrotalcite is 2 - 3:3 - 4:10;

[0025] S203. Add azobenzene - 4,4 - dicarboxylic acid to deionized water, stir evenly, add sodium hydroxide solution, adjust the pH value to 8.5, mix the dispersion with the azobenzene - 4,4 - dicarboxylic acid after adjusting the pH, and introduce N 2 under protection and react for 24 hours. Filter the reacted liquid to obtain a light yellow filter cake, wash the filter cake 3 - 4 times each with deionized water and ethanol, dry in a vacuum oven at 60 °C and then grind to obtain a light yellow solid, which is the hydrotalcite flame retardant with a self - crosslinking group - containing nanolayer structure; the mass ratio of azobenzene - 4,4 - dicarboxylic acid to hydrotalcite is 1:5.

[0026] The interlayer anions of hydrotalcite interact with the positively charged layer board by means of weak electrostatic attraction, hydrogen bonds and van der Waals forces. Therefore, the interlayer anions of hydrotalcite can be changed by ion exchange. Among them, NO 3 - is the most easily exchanged anion, and anions with higher valences are more likely to enter the interlayer of hydrotalcite through ion exchange. Therefore, we select dodecyl phosphoric acid and inositol hexaphosphate so that the phosphate anions can replace NO 3 - and intercalate into the interlayer of hydrotalcite. The intercalated hydrotalcite can provide a carbon source and an acid source at the same time. At the same time, graft azobenzene - 4,4 - dicarboxylic acid onto the hydrotalcite, so that the flame retardant contains the flame - retardant element nitrogen, has a high - temperature self - crosslinking group (N = N) and can generate low - energy free radicals after heating, enabling it to play a role in both the gas phase and the condensed phase. The grafted hydrotalcite is also an efficient ultraviolet absorber, which can improve the anti - aging performance of the composite material. More importantly, it has better compatibility and flame - retardant efficiency with the polymer matrix.

[0027] Furthermore, prepare a flame - retardant high - performance polypropylene composite material, specifically:

[0028] Add the flame retardant, polypropylene matrix and antioxidant to a blender, melt - blend them, the mixing temperature is 190 - 220 °C, the time is 20 - 40 minutes, and the rotation speed is 100 revolutions per minute. The obtained mixing product is the flame - retardant high - performance polypropylene.

[0029] In order to obtain a polypropylene composite material with high melt strength, high rigidity and toughness at the same time, it is very important to control the composition, structure or properties of the dispersed phase and the continuous phase. Through these preferred conditions, the present invention can prepare a polypropylene composite material conducive to achieving the purpose of the present invention, thereby obtaining a polypropylene composite material with better properties.

[0030] Finally, a car floor mat is prepared with this flame-retardant high-performance polypropylene. The prepared kneaded product is injection-molded with an injection molding machine to obtain a flat sample with a thickness of 4 mm, a length of 400 mm, and a width of 400 mm.

[0031] The car floor mat prepared from the polypropylene according to the present invention has good flame-retardant performance, antistatic performance, as well as low-temperature rigidity and toughness. The car floor mat can quickly return to its original state when the external force is removed after deformation. Especially under low-temperature conditions below -30°C, the hardened floor mat still has good rigidity and toughness, is not easily deformed during the process of being stepped on and stressed, and will not interfere with the accelerator and brake pedals, ensuring safe driving.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1) The present invention provides a flame-retardant high-performance polypropylene composite material. Through the cross-linking of polypropylene, several acrylic monomers are polymerized into a high-molecular-weight first copolymer, and then a cross-linked amino-block copolymer is used as the continuous phase, while a hydrotalcite flame retardant with a nano-sheet structure intercalated with a large number of anions and having self-crosslinking groups is used as the dispersed phase. Through cross-linking, the flame retardant and polar small molecules are firmly controlled in the matrix, and their dispersion performance and compatibility are significantly improved, obtaining a composite material with good compatibility and excellent mechanical properties. This material has good wear resistance, good flame-retardant performance, good heat distortion resistance, and good low-temperature flexibility. Due to its special material compounding, this composite material can also absorb ultraviolet light and has good aging resistance. This composite material can be widely used in fields with strict requirements for flame retardancy and smoke emission, such as public places, automotive interior parts, decoration and decoration, etc., and can especially be used as a flame-retardant product under high-strength stress conditions.

[0034] 2) The present invention provides a hydrotalcite flame retardant with a nano-sheet structure intercalated with a large number of anions and having self-crosslinking groups. This flame retardant has a unique nano-sheet structure and is an organic-inorganic hybrid material. It has a carbon source, an acid source and a gas source at the same time, and can provide long-term and efficient flame retardancy; at the same time, the materials used are all environmentally friendly materials and have no harm to the environment and the human body.

[0035] 3) The present invention also provides a foot mat which has high softness. The foot mat made of the composite material prepared by the present invention can reach a softness of 60°, and has good weather resistance. It can be used all-weather, that is, it resists cold in winter and high temperature in summer. It will not produce cracking phenomenon. At relatively high temperatures, there is no any peculiar smell. It has relatively high strength and long service life. The tensile strength of the composite material of the present invention reaches 14 MPa, and has good anti-slip safety. The composite material of the present invention can generate stronger gripping force to prevent slipping and ensure driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the field emission scanning electron microscope image of the hydrotalcite flame retardant with self-crosslinking groups prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention will be further described below in conjunction with the specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content described in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0038] Example 1

[0039] A flame-retardant high-performance polypropylene composite material. First, a polypropylene matrix is prepared, specifically as follows:

[0040] In a reaction kettle, 20 parts of isooctyl acrylate, 50 parts of dimethylaminoethyl methacrylate, 50 parts of hydroxypropyl acrylate, and 2.0 parts of n-dodecyl mercaptan are stirred evenly. Under nitrogen protection, the temperature is slowly raised to 110 °C, and then 3.0 parts of azobisisobutyronitrile as an initiator is added dropwise. After reacting for 1200 minutes, 30 parts of acrylic acid is added and the reaction continues for 150 minutes to obtain a first copolymer with an average molecular weight of 52378, and its side chain is grafted with hydroxyl and amino groups;

[0041] S002, 50 parts of the first copolymer and 10 parts of a styrene-butadiene-styrene polymer with an average molecular weight of 60000 are added to the reaction kettle. Under nitrogen protection, the temperature is raised to 200 °C, and the stirring speed is 500 rpm to disperse the block copolymer in the high-molecular-weight first copolymer, and then 100 parts of polypropylene is added; the reaction continues for 80 minutes to obtain a polymer matrix with a high-molecular network structure;

[0042] Further, a hydrotalcite flame retardant with self-crosslinking groups is prepared, specifically as follows:

[0043] Mix 50 ml of 1 mol / L nitric acid and 500 ml portions of sodium nitrate evenly to obtain an acid mixture; dry 50 portions of hydrotalcite at 80 °C for 5 hours, then place the hydrotalcite in 50 portions of the acid mixture, heat up to 90 °C, stir and soak for 2 hours. After the reaction ends, perform suction filtration, wash 3 times with absolute ethanol, and dry at 80 °C for 20 hours to obtain hydrotalcite with an expanded interlayer spacing; then add 10 portions of glycine and 50 portions of deionized water to the hydrotalcite with an expanded interlayer spacing, and react at 80 °C for 24 hours to obtain a suspension;

[0044] Add 10 portions of dodecyl phosphoric acid and 15 portions of inositol hexaphosphate to the suspension, stir and react at 80 °C for 8 hours to obtain a reaction solution; adjust the pH to neutral with citric acid, obtain the product with a rotary evaporator, place the product in an oven at 80 °C and dry for 12 hours to obtain a white solid with a large amount of anions in the interlayer; disperse the white solid in deionized water to obtain a dispersion;

[0045] Add 10 portions of azobenzene-4,4-dicarboxylic acid to deionized water, stir evenly, add sodium hydroxide solution, adjust the pH value to 8.5, mix the dispersion with the azobenzene-4,4-dicarboxylic acid after adjusting the pH, and pass N 2 Protect, and react for 24 hours; perform suction filtration on the reacted mixture to obtain a light yellow filter cake, wash the filter cake 3 times each with deionized water and ethanol, dry in a vacuum oven at 60 °C and grind to obtain a light yellow solid, which is a hydrotalcite flame retardant with a self-crosslinking group-containing nano-layered structure.

[0046] Finally, add 12 portions of the hydrotalcite flame retardant with a self-crosslinking group-containing nano-layered structure, 100 portions of a polymer network structure polymer matrix, and 2 portions of an antioxidant to a blender, melt and blend, the mixing temperature is 190 °C, the time is 20 minutes, and the rotation speed is 100 revolutions per minute. The obtained mixing product is a flame retardant high-performance polypropylene.

[0047] Use this flame retardant high-performance polypropylene to prepare an automotive floor mat, and inject the prepared mixing product with an injection molding machine to obtain a flat sample with a thickness of 4 mm, a length of 400 mm, and a width of 400 mm.

[0048] Example 2

[0049] A flame retardant high-performance polypropylene composite material requires the preparation of a polypropylene matrix. To prepare the polypropylene matrix, first prepare an aminated block copolymer, which is obtained by modifying a styrene-butadiene-styrene block copolymer. Its preparation method is as follows:

[0050] Dissolve 100 parts of styrene-butadiene-styrene block copolymer in 100 parts of ethyl acetate, stir evenly at a temperature of 70 °C, add 50 parts of maleic anhydride, stir until dissolved, then add 3 parts of initiator benzoyl peroxide, and react for 14 hours under the protection of a nitrogen stream to obtain a block copolymer grafted with maleic anhydride.

[0051] Then, drop 10 parts of N,N-dimethylhexadecyl-1-amine and 20 parts of N,N-dimethylformamide into the block copolymer solution grafted with maleic anhydride. Under the action of 1 part of 4-dimethylaminopyridine, react at a temperature of 70 °C for 24 hours. After the reaction is completed, filter the impurities in the mixed solution to obtain a clear and slightly viscous filtrate. Dry it in an oven at 35 °C and wash it with deionized water multiple times to obtain an aminated block copolymer.

[0052] Furthermore, prepare a polypropylene matrix, specifically

[0053] In a reaction kettle, stir evenly 20 parts of isooctyl acrylate, 50 parts of dimethylaminoethyl methacrylate, 50 parts of hydroxypropyl acrylate, and 2.0 parts of n-dodecyl mercaptan. Under nitrogen protection, slowly heat up to 110 °C, then drop 3.0 parts of azobisisobutyronitrile as the initiator. After reacting fully for 200 minutes, add 30 parts of acrylic acid and continue to react for 150 minutes to obtain a first copolymer with an average molecular weight of 53015, which has hydroxyl and amino groups grafted on its side chains.

[0054] S002, add 50 parts of the first copolymer and 10 parts of the aminated block copolymer to the reaction kettle. Under nitrogen protection, heat up to 200 °C and the stirring speed is 500 rpm to allow the aminated block copolymer to be in the high molecular weight first copolymer, then add 100 parts of polypropylene and continue to react for 80 minutes to obtain a polymer matrix with a high molecular network structure.

[0055] Furthermore, prepare a hydrotalcite flame retardant with self-crosslinking groups, specifically:

[0056] Mix 50 ml of 1 mol / L nitric acid and 500 ml of sodium nitrate evenly to obtain an acid mixture; dry 50 parts of hydrotalcite at 80 °C for 5 hours, then put the hydrotalcite into 50 parts of the acid mixture, heat up to 90 °C, stir and soak for 2 hours. After the reaction is completed, carry out suction filtration, wash it 3 times with absolute ethanol, and dry it at 80 °C for 20 hours to obtain a hydrotalcite with an expanded interlayer spacing; then add 10 parts of glycine and 50 parts of deionized water to the hydrotalcite with an expanded interlayer spacing, and react at 80 °C for 24 hours to obtain a suspension.

[0057] Add 10 parts of dodecyl phosphoric acid and 15 parts of inositol hexaphosphate to the suspension, stir and react at 80 °C for 8 hours to obtain a reaction solution; adjust the pH to neutral with citric acid, obtain the product with a rotary evaporator, place the product in an oven at 80 °C and dry for 12 hours to obtain a white solid with a large amount of anions in the interlayer; disperse the white solid in deionized water to obtain a dispersion;

[0058] Add 10 parts of azobenzene-4,4-dicarboxylic acid to deionized water, stir evenly, add sodium hydroxide solution, adjust the pH value to 8.5, mix the dispersion with azobenzene-4,4-dicarboxylic acid after adjusting the pH, and introduce N 2 under protection and react for 24 hours; filter the reacted mixture to obtain a light yellow filter cake, wash the filter cake 3 times each with deionized water and ethanol, dry in a vacuum oven at 60 °C and then grind to obtain a light yellow solid, which is a hydrotalcite flame retardant with a nano-layered structure with self-crosslinking groups.

[0059] Finally, add 12 parts of the hydrotalcite flame retardant with a nano-layered structure with self-crosslinking groups, 100 parts of a polymer network structure polymer matrix, and 2 parts of an antioxidant to a blender, melt and blend, the mixing temperature is 190 °C, the time is 20 minutes, and the rotation speed is 100 revolutions per minute. The obtained blended product is a flame-retardant high-performance polypropylene.

[0060] Use this flame-retardant high-performance polypropylene to prepare an automotive floor mat, inject the prepared blended product with an injection molding machine to obtain a flat sample with a thickness of 4 mm, a length of 400 mm, and a width of 400 mm.

[0061] Example 3

[0062] A flame-retardant high-performance polypropylene composite material requires the preparation of a polypropylene matrix. To prepare the polypropylene matrix, first prepare an aminated block copolymer, which is obtained by modifying a styrene-butadiene-styrene block copolymer. The preparation method is as follows:

[0063] Dissolve 100 parts of styrene-butadiene-styrene block copolymer in 100 parts of ethyl acetate, stir evenly at a temperature of 70 °C, add 50 parts of maleic anhydride, stir and dissolve, then add 3 parts of initiator dibenzoyl peroxide, and react for 14 hours under the protection of a nitrogen stream to obtain a grafted maleic anhydride block copolymer,

[0064] Then drop 10 parts of N,N-dimethylhexadecyl-1-amine and 20 parts of N,N-dimethylformamide into the solution of the grafted maleic anhydride block copolymer, react at a temperature of 70 °C for 24 hours under the action of 1 part of 4-dimethylaminopyridine. After the reaction is completed, filter the impurities in the mixed solution to obtain a clear and slightly viscous filtrate, dry in an oven at 35 °C, and wash with deionized water multiple times to obtain an aminated block copolymer;

[0065] Further, a polypropylene matrix is prepared, specifically as follows

[0066] In a reaction kettle, 10 parts of isooctyl acrylate, 60 parts of dimethylaminoethyl methacrylate, 60 parts of hydroxypropyl acrylate, and 2.0 parts of n-dodecyl mercaptan are stirred evenly. Under nitrogen protection, the temperature is slowly raised to 110 °C, and then 4.0 parts of azobisisobutyronitrile as an initiator is added dropwise. After reacting fully for 200 minutes, 20 parts of acrylic acid is added and the reaction continues for 150 minutes to obtain a first copolymer with an average molecular weight of 58734, and its side chains are grafted with hydroxyl groups and amino groups;

[0067] S002, 50 parts of the first copolymer and 20 parts of an aminated block copolymer are added to the reaction kettle. Under nitrogen protection, the temperature is raised to 200 °C, and the stirring speed is 500 rpm. The aminated block copolymer continues to react in the high-molecular-weight first copolymer for 80 minutes, and then 100 parts of polypropylene is added to obtain a high-molecular network structure polymer matrix.

[0068] Further, a hydrotalcite flame retardant with self-crosslinking groups is prepared, specifically as follows:

[0069] 50 ml of 1 mol / L nitric acid and 500 ml of sodium nitrate are mixed evenly to obtain an acid mixture; 50 parts of hydrotalcite is dried at 80 °C for 5 hours, and then the hydrotalcite is placed in 50 parts of the acid mixture, the temperature is raised to 90 °C, and it is stirred and soaked for 2 hours. After the reaction ends, it is filtered by suction, washed 3 times with absolute ethanol, and dried at 80 °C for 20 hours to obtain a hydrotalcite with an expanded interlayer spacing; then 10 parts of glycine and 50 parts of deionized water are added to the hydrotalcite with an expanded interlayer spacing, and the reaction is carried out at 80 °C for 24 hours to obtain a suspension. The volume ratio of nitric acid to sodium nitrate is 1:10, the concentration of nitric acid is 0.5 mol / L, and the concentration of sodium nitrate is 1.2 mol / L; the mass ratio of hydrotalcite to the mixed solution of nitric acid and sodium nitrate is 1:1; the mass ratio of glycine to hydrotalcite is 2 - 3:10;

[0070] 10 parts of dodecyl phosphoric acid and 20 parts of inositol hexaphosphate are added to the suspension, and the reaction is stirred at 80 °C for 8 hours to obtain a reaction solution; the pH is adjusted to neutral with citric acid, and the product is obtained with a rotary evaporator. The product is dried in an 80 °C oven for 12 hours to obtain a white solid containing a large amount of anions in the interlayer; the white solid is dispersed in deionized water to obtain a dispersion;

[0071] 10 parts of azobenzene-4,4-dicarboxylic acid is added to deionized water, stirred evenly, and a sodium hydroxide solution is added to adjust the pH value to 8.5. The dispersion is mixed with the azobenzene-4,4-dicarboxylic acid after pH adjustment, and N is introduced at room temperature 2Protect and react for 24 hours; filter the reacted mixture by suction to obtain a light yellow filter cake, wash the filter cake three times each with deionized water and ethanol, dry it in a vacuum oven at 60 °C and then grind it to obtain a light yellow solid, which is the hydrotalcite flame retardant with a self-crosslinking group and a nanolamellar structure.

[0072] Finally, add 9 parts of the hydrotalcite flame retardant with a self-crosslinking group and a nanolamellar structure, 100 parts of the polymer network structure polymer matrix, and 2 parts of antioxidant to a blender, melt and blend them, with a mixing temperature of 190 °C, a time of 20 minutes, and a rotation speed of 100 revolutions per minute. The obtained blended product is the flame-retardant high-performance polypropylene.

[0073] Use this flame-retardant high-performance polypropylene to prepare an automotive floor mat, and inject the prepared blended product with an injection molding machine to obtain a flat sample with a thickness of 4 mm, a length of 400 mm, and a width of 400 mm.

[0074] Example 4

[0075] A flame-retardant high-performance polypropylene composite material requires the preparation of a polypropylene matrix. To prepare the polypropylene matrix, first prepare an aminated block copolymer, which is obtained by modifying a styrene-butadiene-styrene block copolymer. The preparation method is as follows:

[0076] Dissolve 100 parts of the styrene-butadiene-styrene block copolymer in 100 parts of ethyl acetate, stir evenly at a temperature of 70 °C, add 50 parts of maleic anhydride, stir to dissolve it, then add 3 parts of the initiator benzoyl peroxide, and react for 14 hours under the protection of a nitrogen stream to obtain a grafted maleic anhydride block copolymer.

[0077] Then, drop 10 parts of N,N-dimethylhexadecyl-1-amine and 20 parts of N,N-dimethylformamide into the solution of the grafted maleic anhydride block copolymer, react at a temperature of 70 °C for 24 hours under the action of 1 part of 4-dimethylaminopyridine. After the reaction is completed, filter the impurities in the mixed solution to obtain a clear and slightly viscous filtrate, dry it in an oven at 35 °C, and wash it with deionized water multiple times to obtain the aminated block copolymer.

[0078] Furthermore, to prepare the polypropylene matrix, specifically

[0079] In a reaction kettle, stir evenly 10 parts of isooctyl acrylate, 60 parts of dimethylaminoethyl methacrylate, 60 parts of hydroxypropyl acrylate, and 2.0 parts of n-dodecyl mercaptan. Under the protection of nitrogen, slowly heat up to 110 °C, then drop 4.0 parts of azobisisobutyronitrile as the initiator, fully react for 200 minutes, and then add 20 parts of acrylic acid and continue to react for 150 minutes to obtain a first copolymer with an average molecular weight of 58196, and its side chains are grafted with hydroxyl groups and amino groups.

[0080] S002, Add 50 parts of the first copolymer and 20 parts of the aminated block copolymer into a reaction kettle. Under nitrogen protection, heat up to 200 °C with a stirring speed of 500 rpm to allow the aminated block copolymer to be in the high molecular weight first copolymer. Then add 100 parts of polypropylene and continue the reaction for 80 minutes to obtain a polymer matrix with a high molecular weight network structure.

[0081] Further, prepare a hydrotalcite flame retardant with self-crosslinking groups, specifically:

[0082] Mix 50 ml of 1 mol / L nitric acid and 500 parts of sodium nitrate evenly to obtain an acid mixture; dry 50 parts of hydrotalcite at 80 °C for 5 hours, then place the hydrotalcite in 50 parts of the acid mixture, heat up to 90 °C, stir and soak for 2 hours. After the reaction, filter by suction, wash 3 times with absolute ethanol, and dry at 80 °C for 20 hours to obtain a hydrotalcite with an expanded interlayer spacing; then add 15 parts of glycine and 50 parts of deionized water to the hydrotalcite with an expanded interlayer spacing, and react at 80 °C for 24 hours to obtain a suspension;

[0083] Add 15 parts of dodecyl phosphoric acid and 15 parts of inositol hexaphosphate to the suspension, stir and react at 80 °C for 8 hours to obtain a reaction solution; adjust the pH to neutral with citric acid, obtain the product with a rotary evaporator, place the product in an oven at 80 °C and dry for 12 hours to obtain a white solid with a large amount of anions in the intercalation; disperse the white solid in deionized water to obtain a dispersion;

[0084] Add 10 parts of azobenzene-4,4-dicarboxylic acid to deionized water, stir evenly, add a sodium hydroxide solution, adjust the pH value to 8.5, mix the dispersion with the azobenzene-4,4-dicarboxylic acid after adjusting the pH, and introduce N 2 Protect and react for 24 hours; filter the reaction mixture by suction to obtain a light yellow filter cake, wash the filter cake 3 times each with deionized water and ethanol, dry in a vacuum oven at 60 °C and grind to obtain a light yellow solid, which is the hydrotalcite flame retardant with a nano-layered structure with self-crosslinking groups. The mass ratio of azobenzene-4,4-dicarboxylic acid to hydrotalcite is 1:5.

[0085] Finally, add 11 parts of the hydrotalcite flame retardant with a nano-layered structure with self-crosslinking groups, 120 parts of the polymer matrix with a high molecular weight network structure and 2 parts of antioxidant into a blender, melt and blend them. The mixing temperature is 190 °C, the time is 20 minutes, and the rotation speed is 100 revolutions per minute. The obtained mixing product is the flame retardant high-performance polypropylene.

[0086] Prepare an automotive floor mat with this flame-retardant high-performance polypropylene. Inject the prepared kneaded product using an injection molding machine to obtain a flat sample with a thickness of 4 mm, a length of 400 mm, and a width of 400 mm. In Comparative Example 1, the crosslinked block copolymer in the polypropylene matrix is not used, and the first copolymer is directly substituted in equal amounts, with the others being the same as in Example 2;

[0087] In Comparative Example 2, the flame retardant is directly replaced with natural hydrotalcite in equal amounts, with the others being the same as in Example 2; In Comparative Example 3, the flame retardant does not use azobenzene-4,4-dicarboxylic acid grafted hydrotalcite and does not have a self-crosslinking group, with the others being the same as in Example 2;

[0088] In Comparative Example 4, the crosslinked block copolymer in the polypropylene matrix is not used, and the first copolymer is directly substituted in equal amounts. The flame retardant is directly replaced with natural hydrotalcite in equal amounts, with the others being the same as in Example 2.

[0089] Test effect comparison data

[0090] 1) Scanning electron microscopy

[0091] The morphology of the hydrotalcite flame retardant with a self-crosslinking group in Example 2 was observed using a field emission scanning electron microscope. Before the test, the flame retardant sample in Example 1 was evenly dispersed on the conductive adhesive, and the parameters of the scanning electron microscope were adjusted. The acceleration voltage was set to 3.0 kV and the magnification was set to 1000 times; the morphology is shown in Figure 1 , from Figure 1 it can be seen that this flame retardant has a unique nano-sheet structure, with small size and relatively uniform dispersion. Due to the rich anions on the surface, there is a slight mutual attraction phenomenon locally. After being added to the cationic polypropylene matrix, due to the action of positive and negative charges, agglomeration will be reduced and it will be evenly dispersed in the matrix.

[0092] 2) Mechanical properties test of polypropylene composites

[0093] The flat samples prepared in Examples 1-4 and Comparative Examples 1-4 were cut into samples with a test size of 300*300 mm. Before the test, the thickness of the middle part of the samples was measured three times with a micrometer and the average value was taken. Then, the two ends of the samples were respectively clamped at both ends of the fixture. At room temperature, the tensile speed was set to 10 mm / min, and the tensile strength (Ts) and elongation at break (Eb) of the samples to be tested were measured. Hardness and cold resistance tests were also carried out on the samples of Examples 1-4 and Comparative Examples 1-4. See Table 1 for details. It can be seen from Table 1 that in Examples 1-4, when there is a crosslinked block copolymer in the polypropylene matrix, because a combination of hard and soft materials is selected and the continuous phase and the dispersed phase are tightly combined, the hardness of the finally prepared polypropylene composite material decreases, but its tensile strength and elongation at break are significantly improved. Moreover, after crosslinking and modifying the aminated block copolymer, its low-temperature resistance is significantly improved.

[0094] Table 1 Record Sheet for Mechanical Property Tests of Polypropylene Composites

[0095]

[0096] 3) Elastic Capacity Test and Anti-Aging Property Test of Polypropylene Composites

[0097] Samples of Examples 1-4 and Comparative Examples 1-4 were subjected to elastic capacity test and anti-aging property test, and the results are shown in Table 2;

[0098] The elastic capacity test was carried out using the following test method: Sample test size: 300*300 mm, Temperature: -30 °C, Constant temperature time: 24 hours Test steps: The cut samples were divided into two groups, with 3 parallel samples in each group. One group was curled along the product injection direction, and the other group was curled perpendicular to the injection direction. They were successively curled into cylinders with a diameter of 80 mm, fixed with rubber bands, and placed in an oven at -30 °C for 24 hours. After the constant temperature curling was completed, the binding rubber bands were quickly untied, and it was allowed to spread horizontally freely in the oven while keeping the temperature unchanged. The distance h from the sample edge to the horizontal support surface was measured after 25 minutes. The smaller the distance h, the better the deformation recovery of the sample material. Generally, h≤5 mm is considered qualified.

[0099] For the anti-aging property test, the samples were subjected to 1000h xenon lamp accelerated aging experiment, and the breaking strength before and after the aging test was compared to obtain the breaking strength retention rate; It can be seen from Table 2 that in Examples 2-4, since polypropylene was crosslinked with a first copolymer polymerized from acrylic monomers into a high molecular weight, and then crosslinked with an amino-block copolymer as the continuous phase, and a hydrotalcite flame retardant with a nano-layered structure intercalated with a large number of anions with self-crosslinking groups was used as the dispersed phase. Through the action of electrostatic attraction and crosslinking, the flame retardant and polar small molecules were firmly controlled in the matrix, and its dispersion performance and compatibility performance were significantly improved, obtaining a composite material with good compatibility and excellent mechanical properties, which is not easy to deform and has good resilience. And due to the synergistic effect of each component, the composite material has anti-ultraviolet function, is not easy to oxidize, and has excellent high-temperature resistance. In Comparative Examples 2 and 4, since the flame retardant used was natural hydrotalcite and was directly added to the matrix, it would cause the mechanical properties of the matrix to decline rapidly and the anti-aging ability to be significantly weakened. In Comparative Example 3, since the azo group with self-crosslinking groups was not introduced, the anti-aging performance decreased significantly. Generally speaking, the improvement of the mechanical properties and anti-aging properties of the composite material is the result of the synergistic effect of each component.

[0100] Table 2 Elastic Capacity Test and Anti-Aging Property Test of Polypropylene Composites

[0101] Sample Distance h (mm) Retention rate of breaking strength (%) Example 1 2.8 83.7 Example 2 1.3 95.5 Example 3 1.2 96.2 Example 4 1.1 95.9 Comparative Example 1 7.3 82.8 Comparative Example 2 5.5 54.8 Comparative Example 3 1.3 77.3 Comparative Example 4 7.9 43.9

[0102] 4) Flame Retardant Property of Polypropylene Composites

[0103] The limiting oxygen index tests were carried out on the flat samples of Examples 1-4 and Comparative Examples 1-4, and the UL-94 combustion test results are shown in Table 3. It can be seen from the data in Table 3 that when natural hydrotalcite was added as a flame retardant, the flame retardant effect was poor and it belonged to combustible materials. However, in Examples 1-4, a hydrotalcite flame retardant with a nano-layered structure intercalated with a large amount of anions and having self-crosslinking groups was added. It is an organic-inorganic hybrid material that simultaneously has a carbon source, an acid source and a gas source. After being heated, it can expand and cover the surface of the matrix, protect the matrix, effectively block the heat transfer, reduce the thermal degradation rate, achieve the effect of isolating the fire source, delaying and interrupting the flame spread. Phosphorus and nitrogen elements were grafted onto the hydrotalcite. At the same time, during the combustion process of the matrix, the flame retardant can generate acid substances such as phosphoric acid, promote the dehydration and carbonization of the matrix during combustion, accelerate the formation of the carbon layer, and the generated free radicals can quench the combustion chain reaction and prevent the combustion reaction from proceeding. The introduced nitrogen element will also generate incombustible gases during the combustion process, diluting the concentration of oxygen in the combustion system. The introduced hydrotalcite can improve the density of the carbon layer on the surface of the matrix, further improving the flame retardant performance of the matrix. Each component synergistically exerts flame retardancy, endowing the polypropylene composite with excellent flame retardant efficacy.

[0104] Table 3 Flame Retardant Performance Test Results of Polypropylene Composites

[0105] Sample UL-94 combustion test rating Limiting oxygen index (%) Test standard ASTM D3801 GB / T 2406.2-2009 Example 1 V-0 34.4 Example 2 V-0 33.8 Example 3 V-0 32.5 Example 4 V-0 31.6 Comparative Example 1 V-1 25.1 Comparative Example 2 - 19.9 Comparative Example 3 V-0 30.5 Comparative Example 4 - 17.3

[0106] Thus, it can be seen that the flame retardant high-performance polypropylene composite provided by this application can efficiently retard fire, has flexibility, flexible wear resistance and anti-aging performance, and is a flame retardant high-performance polypropylene material.

[0107] The above is only used to illustrate the technical solution of the present invention and not to limit it. Any equivalent modification and change made by those of ordinary skill in the art to the technical solution of the present invention still belong to the scope covered by the present invention as long as they do not depart from the overall concept of the present invention.

Claims

1. A flame retardant high-performance polypropylene composite material, characterized in that: The flame retardant high-performance polypropylene composite material is prepared from the following raw materials in parts by mass: 100 to 120 parts of polypropylene matrix; 9 to 12 parts of flame retardant; 0.1 to 2.5 parts of antioxidant; Wherein, the polypropylene matrix is ​​a high molecular weight network structure polymer matrix obtained by polymerizing acrylic acid monomers into a first copolymer and cross-linking a block copolymer; The flame retardant is a hydrotalcite flame retardant with self-crosslinking groups.

2. The flame retardant high performance polypropylene composite material according to claim 1, characterized in that: The polypropylene matrix and its preparation method are specifically as follows: S001: In a reaction kettle, isooctyl acrylate, dimethylaminoethyl methacrylate, hydroxypropyl acrylate and n-dodecyl mercaptan are stirred evenly, and the temperature is slowly raised to 110-150° C. under nitrogen protection, and then an initiator azobisisobutyronitrile is added dropwise. After fully reacting for 150-200 minutes, acrylic acid is added and the reaction is continued for 100-150 minutes to obtain a first high molecular weight copolymer with an average molecular weight of 50,000-60,000, and hydroxyl groups and amine groups are grafted on the side chains; S002, adding the first copolymer and the block copolymer into a reaction kettle, raising the temperature to 200-220° C. under nitrogen protection, stirring at a speed of 500 rpm, dispersing the block copolymer in the high molecular weight first copolymer, adding polypropylene, and continuing to stir and react for 60-80 minutes to obtain a high molecular weight network structure polymer matrix; The mass fraction of the dimethylaminoethyl methacrylate is 50-60 parts, the mass fraction of isooctyl acrylate is 10-20 parts, the mass fraction of acrylic acid is 20-30 parts, the mass fraction of hydroxypropyl acrylate is 50-60 parts, the mass fraction of n-dodecyl mercaptan is 1.0-2.5 parts, and the mass fraction of azobisisobutyronitrile is 2.0-4.0 parts.

3. The flame retardant high performance polypropylene composite material according to claim 1, characterized in that: in, The aminated block copolymer is obtained by modifying a styrene-butadiene-styrene block copolymer, and the preparation method thereof is specifically as follows: S101, dissolving styrene-butadiene-styrene block copolymer in ethyl acetate, stirring evenly at a temperature of 60-70° C., adding maleic anhydride, stirring and dissolving, adding initiator dibenzoyl peroxide, and reacting for 12-14 hours under the protection of nitrogen flow to obtain a block copolymer grafted with maleic anhydride, S102, N,N-dimethylhexadecyl-1-amine and N,N-dimethylformamide are added dropwise to the block copolymer solution grafted with maleic anhydride, and reacted at a temperature of 60-70°C for 24-30 hours under the action of a dehydrating agent 4-dimethylaminopyridine. After the reaction is completed, the impurities in the mixed solution are filtered to obtain a clear and slightly viscous filtrate, which is dried in an oven at 35°C and washed with deionized water for multiple times to obtain an aminated block copolymer; wherein the mass ratio of N,N-dimethylhexadecyl-1-amine to styrene-butadiene-styrene block copolymer is 1:10; and the mass ratio of N,N-dimethylhexadecyl-1-amine to N,N-dimethylformamide is 1:

2.

4. The flame retardant high performance polypropylene composite material according to claim 1, characterized in that: The preparation method of the hydrotalcite flame retardant with self-crosslinking groups is specifically as follows: S201, drying the hydrotalcite at 80°C for 5 hours, then heating the hydrotalcite to 90°C in a mixed solution of nitric acid and sodium nitrate, stirring and soaking for 2 hours, after the reaction is completed, filtering, washing with anhydrous ethanol for 3 times, and drying at 80°C for 20 hours to obtain a hydrotalcite with an enlarged interlayer spacing; then adding glycine and deionized water to the hydrotalcite with an enlarged interlayer spacing, reacting at 60-80°C for 24 hours to obtain a suspension, wherein the volume ratio of nitric acid to sodium nitrate is 1:10, the concentration of nitric acid is 0.5 mol / L, and the concentration of sodium nitrate is 1.2 mol / L; the mass ratio of hydrotalcite to the mixed solution of nitric acid and sodium nitrate is 1:1; the mass ratio of glycine to hydrotalcite is 2-3:10; S202, adding dodecyl phosphate and inositol hexaphosphate to the suspension, stirring and reacting at 60-80° C. for 6-8 hours to obtain a reaction solution; adjusting the pH to neutral with citric acid, obtaining a product with a rotary evaporator, and drying the product in an oven at 80° C. for 12 hours to obtain a white solid containing a large amount of anions in the intercalation layer; The white solid is dispersed in deionized water to obtain a dispersion; the mass ratio of dodecyl phosphate, inositol hexaphosphate and hydrotalcite is 2-3:3-4:10; S203, adding azobenzene-4,4-dicarboxylic acid to deionized water, stirring evenly, adding sodium hydroxide solution, adjusting the pH value to 8.5, mixing the dispersion with the azobenzene-4,4-dicarboxylic acid after adjusting the pH, introducing N2 protection at room temperature, and reacting for 24 hours; filtering the liquid after the reaction to obtain a light yellow filter cake, washing the filter cake with deionized water and ethanol for 3-4 times respectively, drying in a vacuum oven at 60° C., and grinding to obtain a light yellow solid, which is a hydrotalcite flame retardant with a nano-lamellar structure having a self-crosslinking group, and the mass ratio of azobenzene-4,4-dicarboxylic acid to hydrotalcite is 1:

5.

5. The flame retardant high performance polypropylene composite material according to claim 1, characterized in that: The block copolymer is a styrene-butadiene-styrene block copolymer or an aminated block copolymer.

6. The flame retardant high performance polypropylene composite material according to claim 1, characterized in that: The mass ratio of the block copolymer, the first copolymer and the polypropylene is 2-4:10:100; the molecular weight of the block copolymer is 60,000-70,000.

7. A method for preparing flame-retardant high-performance polypropylene, characterized in that: Add flame retardant, polypropylene matrix and antioxidant into a mixer, melt blend, mix at a temperature of 190-220°C, for 20-40 minutes, at a rotation speed of 100 rpm, and obtain a mixed product, which is flame retardant high-performance polypropylene.

8. A car mat, characterized in that: Made from the flame retardant high performance polypropylene according to any one of claims 1 to 7.

Images