Flame-retardant toughening agent for polypropylene material and preparation method of flame-retardant toughening agent

Abstract

The invention relates to a flame-retardant toughening agent for a polypropylene material and a preparation method of the flame-retardant toughening agent, and belongs to the technical field of macromolecular flame-retardant toughening, and the preparation method comprises the following steps: firstly combining an aromatic compound with melamine, and then combining with a flame-retardant material to obtain a flame-retardant compound; the preparation method comprises the following steps: combining itaconic anhydride, a modified toughening agent, octavinyl silsesquioxane and polypropylene through graft copolymerization to obtain grafted polypropylene; combining the flame-retardant compound with grafted polypropylene to obtain a modified flame-retardant toughening agent; and mixing the modified flame-retardant toughening agent with an antioxidant and a lubricant, and carrying out melt blending extrusion to obtain the flame-retardant toughening agent for the polypropylene material. According to the technical scheme, the aromatic compound, the melamine and the flame-retardant material are combined, so that the flame-retardant property of the polypropylene material is effectively improved; the itaconic anhydride, the modified toughening agent and the octavinyl silsesquioxane are combined with the polypropylene, so that the impact toughness and the mechanical property of the polypropylene material are enhanced, and the comprehensive performance of the flame-retardant toughening agent is generally improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer flame retardant toughening, and in particular relates to a flame retardant toughening agent for polypropylene material and a preparation method thereof. Background Art

[0002] Polypropylene is a thermoplastic synthetic resin with excellent performance. It is a colorless, translucent, thermoplastic, lightweight general-purpose plastic. It has a wide source, low price, and is easy to form and process, but polypropylene is brittle at low temperatures and has low mechanical strength, so polypropylene is often blended and modified. At present, the more mature technology is to blend and modify polypropylene with rubber toughening agents or thermoplastic elastomer toughening agents to achieve the purpose of toughening. Although the blending effect of polypropylene and rubber or thermoplastic elastomer is good, the toughening effect is relatively low, and the increase in the toughening agent content will lead to a decrease in the strength and rigidity of polypropylene. In addition, polypropylene is flammable, has a fast burning speed, a large amount of heat, produces a large amount of droplets, and is very easy to spread flames, which greatly limits the application range of polypropylene materials. Therefore, how to effectively improve the flame retardant properties and impact toughness of polypropylene is a key problem to be solved in the application of polypropylene materials.

[0003] At present, flame retardant and toughening agent for polypropylene materials is mainly prepared by adding flame retardant and toughening agent into polypropylene. Although it can improve its flame retardancy and toughness, the improvement of toughness often leads to the reduction of flame retardancy, so that polypropylene cannot have both flame retardant and toughening effects at the same time. Existing flame retardants need to be added in a large amount to achieve a good flame retardant effect, but too much addition will cause the mechanical properties of polypropylene to decrease, and the compatibility between flame retardant and polypropylene needs to be further improved. Therefore, it is necessary to prepare a flame retardant and toughening agent for polypropylene materials with good flame retardancy, impact toughness, mechanical properties and good compatibility. Summary of the invention

[0004] The technical problem to be solved by the present invention is as follows: At present, the flame retardant and toughening agent for polypropylene materials is mainly prepared by adding flame retardants and toughening agents into polypropylene. Although the flame retardancy and toughness can be improved, the flame retardancy is often reduced while the toughness is improved, so that the polypropylene cannot have both flame retardant and toughening effects at the same time; the existing flame retardants need to be added in a large amount to achieve a good flame retardant effect, but too much addition will cause the mechanical properties of polypropylene to decrease, and the compatibility between the flame retardant and polypropylene needs to be further improved; therefore, it is necessary to prepare a flame retardant and toughening agent for polypropylene materials with good flame retardancy, impact toughness, mechanical properties and good compatibility.

[0005] The object of the present invention is to provide a flame retardant toughening agent for polypropylene material and a preparation method thereof. The object of the present invention can be achieved by the following technical solutions: A method for preparing a flame retardant toughening agent for polypropylene material comprises the following steps: S1: combining the aromatic compound with melamine first, and then combining it with the flame retardant material to obtain a flame retardant composite; S2: combining itaconic anhydride, modified toughening agent, octavinylsilsesquioxane and polypropylene through graft copolymerization to obtain grafted polypropylene; S3: combining the flame retardant compound in step S1 with the grafted polypropylene in step S2 to obtain a modified flame retardant toughening agent; S4: uniformly mixing the modified flame retardant toughening agent in step S3 with the antioxidant and the lubricant, and extruding the mixture by melt blending to obtain the flame retardant toughening agent for polypropylene material.

[0006] The flame retardant composite is obtained by combining an aromatic compound with melamine and then with a flame retardant material; the aromatic compound is composed of a mixture of vanillin and eugenol, has good antioxidant properties, and can be used as a carbon source, melamine can be used as a gas source, and the flame retardant material is composed of a mixture of phytic acid and boric acid, has good synergistic flame retardant effect, and can be used as an acid source; the aromatic compound, melamine and the flame retardant material can be combined to form an intumescent flame retardant composite, which effectively improves the flame retardant properties of the polypropylene material; itaconic anhydride, a modified toughening agent, octavinylsilsesquioxane and polypropylene are combined by graft copolymerization to obtain a grafted polypropylene; the toughening agent is composed of ethylene -Methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer are mixed, and the two have a synergistic toughening effect; octavinylsilsesquioxane can produce a synergistic flame retardant effect with the flame retardant composite, and the obtained grafted polypropylene can be used as a compatibilizer to improve the compatibility between the toughening agent and polypropylene; the flame retardant composite and the grafted polypropylene are combined to obtain a modified flame retardant toughening agent; the compatibility between the flame retardant composite and polypropylene is enhanced, the modified flame retardant toughening agent is mixed with an antioxidant and a lubricant, and the mixture is melt-blended and extruded to finally obtain a flame retardant toughening agent for polypropylene materials; the overall performance of the flame retardant toughening agent for polypropylene materials is improved, and the environmental protection is good.

[0007] Furthermore, step S1 is specifically as follows: A1: adding an aromatic compound and melamine to anhydrous ethanol, and then refluxing and stirring at 45-55° C. for 3-4 hours under a nitrogen atmosphere, removing the anhydrous ethanol by rotary evaporation, and vacuum drying at 75-85° C. for 3-5 hours to obtain a composite; A2: Add the composite into deionized water to obtain solution A, add the flame retardant material into deionized water to obtain solution B, add solution B into solution A and stir for 25-35 minutes, then age at 75-85°C for 3-5 hours, cool to room temperature, filter, wash with deionized water, and finally dry at 65-75°C to obtain a flame retardant composite.

[0008] In the above reaction process, the aromatic compound has an aldehyde group, a hydroxyl group and a carbon-carbon double bond, and melamine has an amino group. The aldehyde group in the aromatic compound can combine with the amino group in melamine, and the melamine is grafted onto the aromatic compound to obtain a composite. In an aqueous solution, the flame retardant material produces phosphate anions and borate anions, and the melamine in the composite produces ammonium ions. The phosphate anions and borate anions in the flame retardant material can combine with the ammonium ions on the melamine through electrostatic interaction, so that the flame retardant material and the composite are combined together to finally obtain a flame retardant composite.

[0009] Furthermore, in step A1, the mass ratio of the aromatic compound, melamine and anhydrous ethanol is 9.8-10.2:10.3-10.7:280-320.

[0010] Furthermore, in step A1, the aromatic compound is composed of vanillin and eugenol mixed in a mass ratio of 0.8-0.9:0.4-0.5.

[0011] Furthermore, in step A2, the mass ratio of the composite to deionized water is 7-8:180-220.

[0012] Furthermore, in step A2, the mass ratio of the flame retardant material to deionized water is 7-7.5:90-110.

[0013] Furthermore, in step A2, the flame retardant material is composed of phytic acid and boric acid mixed in a mass ratio of 1-1.2:0.6-0.7.

[0014] Furthermore, step S2 is specifically as follows: Mix polypropylene, itaconic anhydride, modified toughening agent, and octavinylsilsesquioxane, add xylene and diisopropylbenzene peroxide, stir evenly, and then react at 120-125°C for 3-4h. After the reaction is completed, filter, wash with acetone, and finally vacuum dry at 80-90°C to obtain grafted polypropylene.

[0015] In the above reaction process, itaconic anhydride, modified toughening agent and octavinylsilsesquioxane all have carbon-carbon double bonds. Under the initiation of dicumyl peroxide, itaconic anhydride, modified toughening agent and octavinylsilsesquioxane can be grafted onto the main chain of polypropylene through graft copolymerization reaction to finally obtain grafted polypropylene.

[0016] Furthermore, the mass ratio of the polypropylene, itaconic anhydride, modified toughening agent, octavinylsilsesquioxane, xylene and dicumyl peroxide is 90-100:10-15:10-12:4-6:25-30:0.5-1.

[0017] Furthermore, the preparation method of the modified toughening agent comprises the following steps: Pentaerythritol triacrylate and toughening agent are added to anhydrous ethanol, and then a catalyst is added, and the mixture is stirred and reacted at 80-90° C. for 11-13 hours. After the reaction is completed, the mixture is washed with a sodium bicarbonate aqueous solution and vacuum dried at 70-80° C. for 4-6 hours to obtain a modified toughening agent.

[0018] Furthermore, the mass ratio of the pentaerythritol triacrylate, the toughening agent and the anhydrous ethanol is 9-10:4-5:90-110.

[0019] Furthermore, the toughening agent is composed of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer mixed in a mass ratio of 0.8-1:0.3-0.4.

[0020] Furthermore, the catalyst is triphenylphosphine.

[0021] In the above reaction process, pentaerythritol triacrylate has a carbon-carbon double bond and a hydroxyl group, and the ethylene-methyl acrylate-glycidyl methacrylate in the toughening agent has an epoxy group. The hydroxyl group on the pentaerythritol triacrylate can be combined with the epoxy group on the ethylene-methyl acrylate-glycidyl methacrylate through a ring-opening reaction, and the toughening agent and the pentaerythritol triacrylate are combined together to obtain a modified toughening agent.

[0022] Furthermore, step S3 is specifically as follows: The flame retardant composite in step S1 and the grafted polypropylene in step S2 are added to tetrahydrofuran, and then 1-methylimidazole is added, and refluxed and stirred for 2-3 hours at 60-65° C. in a nitrogen atmosphere, and the tetrahydrofuran is removed by rotary evaporation, and finally vacuum dried at 65-75° C. to obtain a modified flame retardant toughening agent.

[0023] In the above reaction process, the flame retardant compound has phenolic hydroxyl groups, and the grafted polypropylene has anhydride groups on itaconic anhydride. The phenolic hydroxyl groups in the flame retardant compound can be combined with the anhydride groups in itaconic anhydride through an esterification reaction, and the flame retardant compound and the grafted polypropylene are combined together to finally obtain a modified flame retardant toughening agent.

[0024] Furthermore, the mass ratio of the flame retardant composite, grafted polypropylene, tetrahydrofuran and 1-methylimidazole is 1-1.5:4.5-5:40-45:0.2-0.3.

[0025] Furthermore, step S4 is specifically as follows: The modified flame retardant toughening agent, antioxidant and lubricant are mixed evenly and stirred for 10-20 minutes, then added into a twin-screw extruder for melt blending and extrusion, and pelletized after cooling to obtain a flame retardant toughening agent for polypropylene material.

[0026] Furthermore, the mass ratio of the modified flame retardant toughening agent, antioxidant and lubricant is 90-100:6-8:3-4.

[0027] Furthermore, the antioxidant is at least one of antioxidant 1098, antioxidant 1076, and antioxidant 168.

[0028] Furthermore, the lubricant is at least one of zinc stearate, polyethylene wax, and ethylene bisstearamide.

[0029] Furthermore, the working temperature of the twin-screw extruder is 160-170° C., and the main engine speed is 100-200 r / min.

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) In the technical scheme of the present invention, the flame retardant composite is obtained by combining the aromatic compound with melamine first and then with the flame retardant material; the aromatic compound is composed of a mixture of vanillin and eugenol, both of which contain phenolic hydroxyl structures, and the two have a synergistic effect and good antioxidant properties. Vanillin also contains aldehyde groups, which can provide reaction sites for subsequent reactions. Both vanillin and eugenol have excellent carbon-forming abilities during combustion and can be used as carbon sources; the aromatic compound is combined with melamine to have a relatively good flame retardant composite. Good binding force, and the amino group in melamine can also provide reaction sites for subsequent reactions. The more nitrogen elements in melamine can be used as a gas source; the flame retardant material is composed of a mixture of phytic acid and boric acid. Both phytic acid and boric acid have good flame retardant properties. The two have a synergistic flame retardant effect and can be used as an acid source; aromatic compounds, melamine and flame retardant materials are combined to form an intumescent flame retardant composite through the combination of carbon source, gas source and acid source, which further improves the flame retardant properties, thermal stability and mechanical properties of polypropylene materials; (2) In the technical scheme of the present invention, grafted polypropylene is obtained by combining itaconic anhydride, a modified toughening agent, octavinylsilsesquioxane and polypropylene through graft copolymerization; the modified toughening agent is obtained by combining the toughening agent with pentaerythritol triacrylate; the toughening agent is a mixture of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer, the two have a synergistic toughening effect, can better improve the impact toughness of polypropylene materials, and pentaerythritol triacrylate can improve the bonding force between the toughening agent and polypropylene; octavinylsilsesquioxane is a modified toughening agent, ... The silsesquioxane not only has good bonding strength with polypropylene, but also has flame retardant effect, and can produce synergistic flame retardant effect with flame retardant composites, further improving the flame retardant and mechanical properties of polypropylene materials; itaconic anhydride can be used as a compatibilizer for polypropylene, and can provide reaction sites for subsequent reactions; after itaconic anhydride, modified toughening agent, octavinyl silsesquioxane are combined with polypropylene, the whole can also be used as a compatibilizer to improve the compatibility between the toughening agent and polypropylene, thereby further improving the toughness and mechanical properties of polypropylene; (3) In the technical scheme of the present invention, the flame retardant composite is combined with the grafted polypropylene to obtain a modified flame retardant toughening agent; the itaconic anhydride in the grafted polypropylene can be effectively combined with the flame retardant composite, which not only improves the bonding force between the flame retardant composite and the grafted polypropylene, enhances the compatibility between the flame retardant composite and the polypropylene, but also further improves the flame retardant properties, thermal stability and mechanical properties of the polypropylene material; the modified flame retardant toughening agent is uniformly mixed with an antioxidant and a lubricant, and then melt-blended and extruded to obtain a flame retardant toughening agent for a polypropylene material; the prepared flame retardant toughening agent has good flame retardant properties, impact toughness and mechanical properties; (4) In the technical scheme of the present invention, an aromatic compound is first combined with melamine and then with a flame retardant material to obtain a flame retardant composite; itaconic anhydride, a modified toughening agent, octavinylsilsesquioxane and polypropylene are combined to obtain a grafted polypropylene; the flame retardant composite is combined with the grafted polypropylene, and then mixed with an antioxidant and a lubricant, and then melt-blended and extruded to obtain a flame retardant toughening agent for polypropylene materials; the prepared flame retardant toughening agent for polypropylene materials not only has good flame retardant properties, impact toughness, mechanical properties and compatibility, but also has good environmental protection and good overall comprehensive performance, thereby expanding its application range. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The specific parameters of the raw materials used in the present invention are as follows: Vanillin (CAS No.: 121-33-5), eugenol (CAS No.: 97-53-0), melamine (CAS No.: 108-78-1), phytic acid (CAS No.: 83-86-3), boric acid (CAS No.: 10043-35-3), itaconic anhydride (CAS No.: 2170-03-8), octavinylsilsesquioxane (CAS No.: 69655-76-1), pentaerythritol triacrylate (CAS No.: 3524-68-3), all provided by Shanghai MacLean Biochemical Technology Co., Ltd.; ethylene methyl acrylate - Glycidyl methacrylate, containing 32% methyl acrylate and 8% glycidyl methacrylate, was provided by Arkema (China) Investment Co., Ltd.; ethylene-octene copolymer, melt flow index (MFI) of 0.5 g / 10 min (190°C, 2.16 kg), octene content of 25 mol%, was provided by Dow Chemical Company; polypropylene (isotactic polypropylene IPP-013, MFI = 4 ± 2 g / 10 min, 230°C / 2.16 kg, Tm = 163-164°C) was provided by Sinopec Maoming Petrochemical Co., Ltd.

[0033] Example 1 The preparation method of the flame retardant toughening agent for polypropylene material comprises the following steps: S1: Preparation of flame retardant composites: A1: The aromatic compound and melamine are added to anhydrous ethanol in a mass ratio of 9.8:10.3:280, followed by reflux stirring at 45°C for 3 hours in a nitrogen atmosphere, the anhydrous ethanol is removed by rotary evaporation, and vacuum drying is performed at 75°C for 3 hours to obtain a composite, wherein the aromatic compound is composed of vanillin and eugenol mixed in a mass ratio of 0.8:0.4; A2: According to the mass ratio of the composite material to deionized water of 7:180, the composite material was added to deionized water to obtain solution A; according to the mass ratio of the flame retardant material to deionized water of 7:90, the flame retardant material was added to deionized water to obtain solution B; according to the mass ratio of solution B to solution A of 1:1, solution B was added to solution A and stirred for 25 minutes, then aged at 75°C for 3 hours, cooled to room temperature, filtered, washed with deionized water 3 times (the mass of deionized water each time was 2 times the mass of the composite material), and finally dried at 65°C for 24 hours to obtain a flame retardant composite, wherein the flame retardant material was composed of phytic acid and boric acid mixed in a mass ratio of 1:0.6; S2: According to the mass ratio of polypropylene, itaconic anhydride, modified toughening agent, octavinylsilsesquioxane, xylene and dicumyl peroxide of 90:10:10:4:25:0.5, polypropylene, itaconic anhydride, modified toughening agent and octavinylsilsesquioxane were mixed, and xylene and dicumyl peroxide were added, and stirred evenly, and then reacted at 120°C for 3h. After the reaction, it was filtered, washed with acetone for 3 times (the mass of acetone each time was 60% of the mass of xylene), and finally vacuum dried at 80°C for 24h to obtain grafted polypropylene; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of pentaerythritol triacrylate, toughening agent and anhydrous ethanol being 9:4:90, pentaerythritol triacrylate and toughening agent are added into anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of pentaerythritol triacrylate), and stirred for reaction at 80°C for 11 hours. After the reaction is completed, the mixture is washed with 10wt% sodium bicarbonate aqueous solution for 3 times (the mass of each sodium bicarbonate aqueous solution is 15% of the mass of anhydrous ethanol), and vacuum dried at 70°C for 4 hours to obtain a modified toughening agent, wherein the toughening agent is composed of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer mixed in a mass ratio of 0.8:0.3; S3: according to the mass ratio of flame retardant composite, grafted polypropylene, tetrahydrofuran and 1-methylimidazole being 1:4.5:40:0.2, the flame retardant composite in step S1 and the grafted polypropylene in step S2 are added to tetrahydrofuran, and then 1-methylimidazole is added, and refluxed and stirred at 60° C. for 2 h in a nitrogen atmosphere, tetrahydrofuran is removed by rotary evaporation, and finally vacuum dried at 65° C. for 24 h to obtain a modified flame retardant toughening agent; S4: According to the mass ratio of modified flame retardant toughening agent, antioxidant 1098 and zinc stearate of 90:6:3, the modified flame retardant toughening agent, antioxidant 1098 and zinc stearate are evenly mixed, stirred at a speed of 600 rpm for 20 minutes, and then added into a twin-screw extruder for melt blending and extrusion. The operating temperature of the twin-screw extruder is 160°C and the main engine speed is 100 r / min. After cooling and pelletizing, the flame retardant toughening agent for polypropylene material is finally obtained.

[0034] Example 2 The preparation method of the flame retardant toughening agent for polypropylene material comprises the following steps: S1: Preparation of flame retardant composites: A1: The aromatic compound and melamine are added to anhydrous ethanol in a mass ratio of 10:10.5:300, followed by reflux stirring at 50°C for 3.5 hours in a nitrogen atmosphere, the anhydrous ethanol is removed by rotary evaporation, and vacuum drying is performed at 80°C for 4 hours to obtain a composite, wherein the aromatic compound is composed of vanillin and eugenol mixed in a mass ratio of 0.85:0.45; A2: According to the mass ratio of the composite material to deionized water of 7.5:200, the composite material was added to deionized water to obtain solution A, according to the mass ratio of the flame retardant material to deionized water of 7.3:100, the flame retardant material was added to deionized water to obtain solution B, according to the mass ratio of solution B to solution A of 1:1, solution B was added to solution A, and stirred for 30 minutes, then aged at 80°C for 4 hours, cooled to room temperature, filtered, washed with deionized water 3 times (the mass of deionized water each time was twice the mass of the composite material), and finally dried at 70°C for 24 hours to obtain a flame retardant composite, wherein the flame retardant material is composed of phytic acid and boric acid mixed in a mass ratio of 1.1:0.65; S2: According to the mass ratio of polypropylene, itaconic anhydride, modified toughening agent, octavinylsilsesquioxane, xylene and diisopropylbenzene peroxide of 95:13:11:5:28:0.8, polypropylene, itaconic anhydride, modified toughening agent and octavinylsilsesquioxane were mixed, and xylene and diisopropylbenzene peroxide were added, and stirred evenly, and then reacted at 123°C for 3.5h. After the reaction, it was filtered, washed with acetone for 3 times (the mass of acetone each time was 60% of the mass of xylene), and finally vacuum dried at 85°C for 24h to obtain grafted polypropylene; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of pentaerythritol triacrylate, toughening agent and anhydrous ethanol being 9.5:4.5:100, pentaerythritol triacrylate and toughening agent are added to anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of pentaerythritol triacrylate), and stirred for reaction at 85°C for 12 hours. After the reaction is completed, the mixture is washed with 10wt% sodium bicarbonate aqueous solution for 3 times (the mass of each sodium bicarbonate aqueous solution is 15% of the mass of anhydrous ethanol), and vacuum dried at 75°C for 5 hours to obtain a modified toughening agent, wherein the toughening agent is composed of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer mixed in a mass ratio of 0.9:0.35; S3: according to the mass ratio of flame retardant composite, grafted polypropylene, tetrahydrofuran and 1-methylimidazole being 1.3:4.8:43:0.25, the flame retardant composite in step S1 and the grafted polypropylene in step S2 are added to tetrahydrofuran, and then 1-methylimidazole is added, and refluxed and stirred at 63° C. for 2.5 h in a nitrogen atmosphere, tetrahydrofuran is removed by rotary evaporation, and finally vacuum dried at 70° C. for 24 h to obtain a modified flame retardant toughening agent; S4: According to the mass ratio of modified flame retardant toughening agent, antioxidant 1076 and polyethylene wax of 95:7:3.5, the modified flame retardant toughening agent, antioxidant 1076 and polyethylene wax are mixed evenly, stirred at a speed of 700 rpm for 15 minutes, and then added into a twin-screw extruder for melt blending and extrusion. The operating temperature of the twin-screw extruder is 165°C, and the main engine speed is 150r / min. After cooling and pelletizing, the flame retardant toughening agent for polypropylene material is finally obtained.

[0035] Example 3 The preparation method of the flame retardant toughening agent for polypropylene material comprises the following steps: S1: Preparation of flame retardant composites: A1: The aromatic compound and melamine are added to anhydrous ethanol in a mass ratio of 10.2:10.7:320, followed by reflux stirring at 55°C for 4 hours in a nitrogen atmosphere, the anhydrous ethanol is removed by rotary evaporation, and vacuum drying is performed at 85°C for 5 hours to obtain a composite, wherein the aromatic compound is composed of vanillin and eugenol mixed in a mass ratio of 0.9:0.5; A2: According to the mass ratio of the composite material to deionized water of 8:220, the composite material was added to deionized water to obtain solution A; according to the mass ratio of the flame retardant material to deionized water of 7.5:110, the flame retardant material was added to deionized water to obtain solution B; according to the mass ratio of solution B to solution A of 1:1, solution B was added to solution A and stirred for 35 minutes, then aged at 85°C for 5 hours, cooled to room temperature, filtered, washed with deionized water 3 times (the mass of deionized water each time was 2 times the mass of the composite material), and finally dried at 75°C for 24 hours to obtain a flame retardant composite, wherein the flame retardant material was composed of phytic acid and boric acid mixed in a mass ratio of 1.2:0.7; S2: According to the mass ratio of polypropylene, itaconic anhydride, modified toughening agent, octavinylsilsesquioxane, xylene and diisopropylbenzene peroxide being 100:15:12:6:30:1, polypropylene, itaconic anhydride, modified toughening agent and octavinylsilsesquioxane are mixed, and xylene and diisopropylbenzene peroxide are added, and stirred evenly, and then reacted at 125°C for 4h. After the reaction is completed, it is filtered, washed with acetone for 3 times (the mass of acetone each time is 60% of the mass of xylene), and finally vacuum dried at 90°C for 24h to obtain grafted polypropylene; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of pentaerythritol triacrylate, toughening agent and anhydrous ethanol being 10:5:110, pentaerythritol triacrylate and toughening agent are added into anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of pentaerythritol triacrylate), and stirred for reaction at 90°C for 13h. After the reaction is completed, the mixture is washed with 10wt% sodium bicarbonate aqueous solution for 3 times (the mass of each sodium bicarbonate aqueous solution is 15% of the mass of anhydrous ethanol), and vacuum dried at 80°C for 6h to obtain a modified toughening agent, wherein the toughening agent is composed of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer mixed in a mass ratio of 1:0.4; S3: according to the mass ratio of flame retardant composite, grafted polypropylene, tetrahydrofuran and 1-methylimidazole being 1.5:5:45:0.3, the flame retardant composite in step S1 and the grafted polypropylene in step S2 are added to tetrahydrofuran, and then 1-methylimidazole is added, and refluxed and stirred at 65° C. for 3 h in a nitrogen atmosphere, tetrahydrofuran is removed by rotary evaporation, and finally vacuum dried at 75° C. for 24 h to obtain a modified flame retardant toughening agent; S4: According to the mass ratio of modified flame retardant toughening agent, antioxidant and lubricant of 100:8:4, the modified flame retardant toughening agent, antioxidant and lubricant are evenly mixed, stirred at a speed of 800 rpm for 10 minutes, and then added into a twin-screw extruder for melt blending and extrusion. The working temperature of the twin-screw extruder is 170°C and the main engine speed is 200r / min. After cooling and pelletizing, the flame retardant toughening agent for polypropylene material is finally obtained.

[0036] Comparative Example 1 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step A1, the mass of the aromatic compound is replaced by vanillin, and the remaining steps and raw materials are the same as those in Example 3; A1: Vanillin and melamine were added to anhydrous ethanol in a mass ratio of 10.2:10.7:320, followed by reflux stirring at 55°C for 4 h in a nitrogen atmosphere, the anhydrous ethanol was removed by rotary evaporation, and the mixture was vacuum dried at 85°C for 5 h to obtain a composite.

[0037] Comparative Example 2 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step A1, the mass of the aromatic compound is replaced by eugenol, and the remaining steps and raw materials are the same as those in Example 3; A1: Eugenol and melamine were added to anhydrous ethanol in a mass ratio of 10.2:10.7:320, followed by reflux stirring at 55°C for 4 h in a nitrogen atmosphere, and the anhydrous ethanol was removed by rotary evaporation, followed by vacuum drying at 85°C for 5 h to obtain a composite.

[0038] Comparative Example 3 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step A2, the mass of the flame retardant material is replaced by phytic acid, and the remaining steps and raw materials are synchronized with Example 3; A2: According to the mass ratio of the composite to deionized water of 8:220, the composite was added into deionized water to obtain solution A. According to the mass ratio of phytic acid to deionized water of 7.5:110, phytic acid was added into deionized water to obtain solution B. According to the mass ratio of solution B to solution A of 1:1, solution B was added into solution A and stirred for 35 min. Then, the mixture was aged at 85°C for 5 h. After cooling to room temperature, the mixture was filtered and washed with deionized water for 3 times (the mass of deionized water each time was 2 times of the mass of the composite). Finally, the mixture was dried at 75°C for 24 h to obtain a flame retardant composite.

[0039] Comparative Example 4 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step A2, the mass of the flame retardant material is replaced by boric acid, and the remaining steps and raw materials are synchronized with Example 3; A2: According to the mass ratio of the composite to deionized water of 8:220, the composite was added into deionized water to obtain solution A. According to the mass ratio of boric acid to deionized water of 7.5:110, boric acid was added into deionized water to obtain solution B. According to the mass ratio of solution B to solution A of 1:1, solution B was added into solution A and stirred for 35 min. Then, the mixture was aged at 85°C for 5 h. After being cooled to room temperature, the mixture was filtered and washed with deionized water for 3 times (the mass of deionized water each time was 2 times of the mass of the composite). Finally, the mixture was dried at 75°C for 24 h to obtain a flame retardant composite.

[0040] Comparative Example 5 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step S2, itaconic anhydride and the like are replaced by maleic anhydride, and the remaining steps and raw materials are synchronized with Example 3; S2: According to the mass ratio of polypropylene, maleic anhydride, modified toughening agent, octavinylsilsesquioxane, xylene and diisopropylbenzene peroxide of 100:15:12:6:30:1, polypropylene, maleic anhydride, modified toughening agent and octavinylsilsesquioxane were mixed, xylene and diisopropylbenzene peroxide were added, and stirred evenly, and then reacted at 125°C for 4h. After the reaction, it was filtered, washed with acetone for 3 times (the mass of acetone each time was 60% of the mass of xylene), and finally dried in vacuum at 90°C for 24h to obtain grafted polypropylene.

[0041] Comparative Example 6 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step S2, the mass of pentaerythritol triacrylate in the modified toughening agent is replaced by butyl acrylate, and the remaining steps and raw materials are synchronized with Example 3; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of butyl acrylate, toughening agent and anhydrous ethanol being 10:5:110, butyl acrylate and toughening agent are added to anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of butyl acrylate), and the mixture is stirred and reacted at 90°C for 13 hours. After the reaction is completed, the mixture is washed three times with a 10wt% sodium bicarbonate aqueous solution (the mass of each sodium bicarbonate aqueous solution is 15% of the mass of anhydrous ethanol), and vacuum dried at 80°C for 6 hours to obtain a modified toughening agent, wherein the toughening agent is composed of a mixture of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer in a mass ratio of 1:0.4.

[0042] Comparative Example 7 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step S2, the mass of octavinylsilsesquioxane is replaced by KH570, and the remaining steps and raw materials are synchronized with Example 3; S2: According to the mass ratio of polypropylene, itaconic anhydride, modified toughening agent, KH570, xylene and diisopropylbenzene peroxide of 100:15:12:6:30:1, polypropylene, itaconic anhydride, modified toughening agent and KH570 were mixed, and xylene and diisopropylbenzene peroxide were added, and stirred evenly, and then reacted at 125°C for 4 hours. After the reaction, it was filtered, washed with acetone for 3 times (the mass of acetone each time was 60% of the mass of xylene), and finally vacuum dried at 90°C for 24 hours to obtain grafted polypropylene.

[0043] Comparative Example 8 The difference between this comparative example and Example 3 is that when preparing the modified toughening agent, the toughening agent is replaced by ethylene-methyl acrylate-glycidyl methacrylate, and the remaining steps and raw materials are the same as Example 3; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of pentaerythritol triacrylate, ethylene-methyl acrylate-glycidyl methacrylate and anhydrous ethanol being 10:5:110, pentaerythritol triacrylate and ethylene-methyl acrylate-glycidyl methacrylate are added to anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of pentaerythritol triacrylate), and the mixture is stirred and reacted at 90°C for 13h. After the reaction is completed, the mixture is washed three times with a 10wt% sodium bicarbonate aqueous solution (the mass of the sodium bicarbonate aqueous solution is 15% of the mass of the anhydrous ethanol each time), and vacuum dried at 80°C for 6h to obtain a modified toughening agent.

[0044] Comparative Example 9 The difference between this comparative example and Example 3 is that when preparing the modified toughening agent, the toughening agent is replaced by ethylene-octene copolymer, and the remaining steps and raw materials are the same as Example 3; The preparation method of the modified toughening agent comprises the following steps: According to the mass ratio of pentaerythritol triacrylate, ethylene-octene copolymer and anhydrous ethanol being 10:5:110, pentaerythritol triacrylate and ethylene-octene copolymer are added to anhydrous ethanol, and then triphenylphosphine is added (the mass of triphenylphosphine is 2% of the mass of pentaerythritol triacrylate), and the mixture is stirred and reacted at 90°C for 13 hours. After the reaction is completed, the mixture is washed three times with a 10wt% sodium bicarbonate aqueous solution (the mass of each sodium bicarbonate aqueous solution is 15% of the mass of anhydrous ethanol), and vacuum dried at 80°C for 6 hours to obtain a modified toughening agent.

[0045] Comparative Example 10 The difference between this comparative example and Example 3 is that when preparing the flame retardant toughening agent for polypropylene material, in step S3, the flame retardant composite and the grafted polypropylene are directly mixed, and the remaining steps and raw materials are synchronized with Example 3; S3: according to the mass ratio of the flame retardant compound to the grafted polypropylene being 1.5:5, the flame retardant compound in step S1 and the grafted polypropylene in step S2 are mixed and stirred evenly to obtain a modified flame retardant toughening agent.

[0046] The flame retardant toughening agent for polypropylene material prepared in Examples 1-3 and Comparative Examples 1-10 was tested for flame retardancy, impact toughness and mechanical properties. Flame retardancy test: the limiting oxygen index (LOI) was measured according to GB / T 2406.2-2009 "Determination of combustion behavior of plastics by oxygen index method Part II: Room temperature experiment", and the vertical burning level (UL-94) was tested according to GB / T 2406.2-2009 "Determination of combustion performance of plastics by horizontal and vertical methods"; impact toughness test: the impact toughness was tested according to GB / T14153-2002 "General rules for drop weight impact test methods for rigid plastics"; mechanical property test: the tensile strength was tested according to GB / T 1040.1-2006 "Determination of tensile properties of plastics", and the tensile strength was used to characterize the mechanical properties.

[0047] The test results are shown in Table 1 below: Table 1 Performance parameters of flame retardant toughening agents for polypropylene materials prepared in Examples 1-3 and Comparative Examples 1-10

[0048] It can be seen from the data in Table 1 above that, by comparing Comparative Examples 1-4 with Example 3, the mass of the aromatic compound in step A1 is replaced with vanillin or eugenol, or the mass of the flame retardant material in step A2 is replaced with phytic acid or boric acid, and finally a flame retardant toughening agent for polypropylene material is prepared. The test result is worse than that of Example 3, indicating that the aromatic compound composed of a mixture of vanillin and eugenol has a synergistic effect, good antioxidant property, and can be used as a carbon source; the flame retardant material composed of a mixture of phytic acid and boric acid has a good synergistic flame retardant effect and can be used as an acid source; the aromatic compound, melamine and the flame retardant material are combined to form an intumescent flame retardant composite, which can effectively improve the flame retardant properties and mechanical properties of the polypropylene material, and has a good effect on the impact toughness; By comparing Comparative Examples 5-7 with Example 3, it can be seen that the mass of itaconic anhydride and the like in step S2 is replaced by maleic anhydride, or the mass of pentaerythritol triacrylate and the like in the modified toughening agent in step S2 is replaced by butyl acrylate, or the mass of octavinylsilsesquioxane and the like in step S2 is replaced by KH570, and finally a flame retardant toughening agent for polypropylene material is prepared. The test results are worse than those in Example 3, indicating that itaconic anhydride, pentaerythritol triacrylate, octavinylsilsesquioxane and polypropylene are combined, not only the binding force between the polypropylene and the prepared grafted polypropylene can be used as a compatibilizer, which improves the compatibility between the toughening agent and the polypropylene, and further enhances the mechanical properties, impact toughness and mechanical properties of the flame retardant toughening agent for polypropylene material; By comparing Comparative Examples 8-9 with Example 3, it can be seen that the toughening agent is replaced by ethylene-methyl acrylate-glycidyl methacrylate, or the toughening agent is replaced by ethylene-octene copolymer, and finally a flame retardant toughening agent for polypropylene material is prepared. The test results are worse than those of Example 3, indicating that the toughening agent composed of a mixture of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer not only has a good bonding force with polypropylene, but also has a synergistic effect between ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer, which can better improve the impact toughness of the polypropylene material, and also has a good influence on the flame retardant properties and mechanical properties of the polypropylene material.

[0049] By comparing Comparative Example 10 with Example 3, it can be seen that in step S3, the flame retardant composite and the grafted polypropylene are directly mixed to finally prepare a flame retardant toughening agent for polypropylene material. The test result is worse than that of Example 3, indicating that the flame retardant composite and the grafted polypropylene are effectively combined, which can increase the binding force between the flame retardant composite and the grafted polypropylene, improve the compatibility between the flame retardant composite and the polypropylene, further improve the flame retardant properties, thermal stability and mechanical properties of the polypropylene material, and also have a good enhancing effect on its impact toughness.

[0050] It can be seen from the data in Table 1 above that the flame retardant and toughening agent for polypropylene material prepared in Examples 1-3 is compared with the flame retardant and toughening agent for polypropylene material prepared in Comparative Examples 1-10. The flame retardant and toughening agent for polypropylene material prepared in Examples 1-3 is obtained by combining an aromatic compound with melamine first and then with a flame retardant material to obtain a flame retardant composite; itaconic anhydride, a modified toughening agent, and octavinylsilsesquioxane are combined with polypropylene to obtain a grafted polypropylene; the flame retardant composite is combined with the grafted polypropylene, and then mixed with an antioxidant and a lubricant, and melt blended and extruded to obtain a flame retardant and toughening agent for polypropylene material, which meets the test performance requirements, while the flame retardant and toughening agent for polypropylene material prepared in Comparative Examples 1-10 does not meet the performance requirements. The flame retardant and toughening agent for polypropylene material prepared in the present invention has good flame retardancy, impact toughness, mechanical properties and compatibility, good environmental protection, and good overall comprehensive performance.

[0051] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0052] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a flame retardant toughening agent for polypropylene material, characterized in that: The following steps are involved: S1: combining the aromatic compound with melamine first, and then combining it with the flame retardant material to obtain a flame retardant composite; S2: combining itaconic anhydride, modified toughening agent, octavinylsilsesquioxane and polypropylene through graft copolymerization to obtain grafted polypropylene; S3: combining the flame retardant compound in step S1 with the grafted polypropylene in step S2 to obtain a modified flame retardant toughening agent; S4: uniformly mixing the modified flame retardant toughening agent in step S3 with the antioxidant and the lubricant, and extruding the mixture by melt blending to obtain a flame retardant toughening agent for polypropylene material; The antioxidant is at least one of antioxidant 1098, antioxidant 1076, and antioxidant 168; The lubricant is at least one of zinc stearate, polyethylene wax and ethylene bisstearamide.

2. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 1, characterized in that: Step S1 is specifically as follows: A1: adding an aromatic compound and melamine to anhydrous ethanol, and then refluxing and stirring at 45-55° C. for 3-4 hours under a nitrogen atmosphere, removing the anhydrous ethanol by rotary evaporation, and vacuum drying at 75-85° C. for 3-5 hours to obtain a composite; A2: Add the composite into deionized water to obtain solution A, add the flame retardant material into deionized water to obtain solution B, add solution B into solution A and stir for 25-35 minutes, then age at 75-85°C for 3-5 hours, cool to room temperature, filter, wash with deionized water, and finally dry at 65-75°C to obtain a flame retardant composite.

3. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 2, characterized in that: In step A1, the aromatic compound is composed of vanillin and eugenol mixed in a mass ratio of 0.8-0.9:0.4-0.

5.

4. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 2, characterized in that: In step A2, the flame retardant material is composed of phytic acid and boric acid mixed in a mass ratio of 1-1.2:0.6-0.

7.

5. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 1, characterized in that: Step S2 is specifically as follows: Mix polypropylene, itaconic anhydride, modified toughening agent, and octavinylsilsesquioxane, add xylene and diisopropylbenzene peroxide, stir evenly, and then react at 120-125°C for 3-4h. After the reaction is completed, filter, wash with acetone, and finally vacuum dry at 80-90°C to obtain grafted polypropylene.

6. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 5, characterized in that: The preparation method of the modified toughening agent comprises the following steps: Pentaerythritol triacrylate and toughening agent are added to anhydrous ethanol, and then a catalyst is added, and the mixture is stirred and reacted at 80-90° C. for 11-13 hours. After the reaction is completed, the mixture is washed with a sodium bicarbonate aqueous solution and vacuum dried at 70-80° C. for 4-6 hours to obtain a modified toughening agent; the catalyst is triphenylphosphine.

7. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 6, characterized in that: The toughening agent is composed of ethylene-methyl acrylate-glycidyl methacrylate and ethylene-octene copolymer mixed in a mass ratio of 0.8-1:0.3-0.

4.

8. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 1, characterized in that: Step S3 is specifically as follows: The flame retardant composite in step S1 and the grafted polypropylene in step S2 are added to tetrahydrofuran, and then 1-methylimidazole is added, and refluxed and stirred for 2-3 hours at 60-65° C. in a nitrogen atmosphere, and the tetrahydrofuran is removed by rotary evaporation, and finally vacuum dried at 65-75° C. to obtain a modified flame retardant toughening agent.

9. The method for preparing a flame retardant toughening agent for polypropylene material according to claim 1, characterized in that: Step S4 is specifically as follows: The modified flame retardant toughening agent, antioxidant and lubricant are mixed evenly and stirred for 10-20 minutes, then added into a twin-screw extruder for melt blending and extrusion, and pelletized after cooling to obtain a flame retardant toughening agent for polypropylene material.

10. A flame retardant toughening agent for polypropylene material obtained by the preparation method according to any one of claims 1 to 9.

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