Polyurethane foam material, preparation method and application

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a polyurethane foam material, a preparation method and application. The preparation method of the polyurethane foam material comprises the following steps: carrying out a reaction on pentaerythritol diphosphate diphosphoryl chloride and pentaerythritol to prepare phosphate, carrying out a reaction on the phosphate and melamine to prepare a nitrogen-phosphorus flame retardant, and carrying out a reaction on the nitrogen-phosphorus flame retardant and an epoxy modified inorganic flame retardant to prepare a composite flame retardant; the preparation method comprises the following steps: reacting graphene oxide with polyisocyanate to prepare surface modified graphene oxide, and reacting the surface modified graphene oxide with silver nitrate to prepare Ag < + > / graphene oxide; the polyurethane foam material prepared by adding the composite flame retardant and Ag < + > / graphene oxide has good flame retardant property, antibacterial property and mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a polyurethane foam material, a preparation method and an application thereof. Background Art

[0002] Polyurethane foam is widely used in automotive interiors due to its multiple advantages, including lightweight, sound absorption, sound insulation, and vibration reduction. However, polyurethane foam has a low oxygen index and is highly flammable. In the event of a collision and fire, polyurethane foam interiors can accelerate combustion, increasing the risk. Therefore, there is a need to effectively improve the flame retardant properties of polyurethane foam. Furthermore, after rain or in seasons or areas with high humidity, the foam structure easily absorbs moisture. Cars are often enclosed, which can easily lead to bacterial growth and reproduction, posing a potential health hazard to drivers and passengers. Therefore, there is a need to improve the antibacterial properties of polyurethane foam.

[0003] Chinese patent CN114835873B discloses a high-resilience polyurethane sponge for automotive interiors. The flame retardancy of the polyurethane sponge is enhanced by adding a tris(1,3-dichloro-2-propyl) phosphate flame retardant. However, the flame retardant component is single, and the small-molecule organic flame retardant easily migrates within the polyurethane matrix, leaving room for improvement in flame retardancy. Furthermore, the antibacterial properties of the polyurethane material also need to be improved. Chinese patent application CN110819102A discloses a sound-insulating and antibacterial polyurethane foam board. Nano-silver-loaded zeolite is used to prevent bacterial growth within the foam board. However, the antibacterial properties of the board are reduced due to poor dispersion uniformity between the nano-silver-loaded zeolite and the polyurethane matrix. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a polyurethane foam material to solve the problem in the prior art that the flame retardant and antibacterial properties of the polyurethane foam material need to be improved.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a polyurethane foam material comprises the following steps:

[0007] Step 1: Preparation of composite flame retardant and Ag + / graphene oxide

[0008] The preparation of the composite flame retardant comprises the following steps:

[0009] S11, pentaerythritol diphosphate diphosphoryl chloride reacts with pentaerythritol to prepare a phosphate ester;

[0010] S12, phosphoric acid ester reacts with melamine to prepare nitrogen-phosphorus flame retardant;

[0011] S13, reacting the nitrogen-phosphorus flame retardant with the epoxy-modified inorganic flame retardant to prepare a composite flame retardant;

[0012] Among them, Ag + / Preparation of graphene oxide, comprising the following steps:

[0013] S21, reacting graphene oxide with polyisocyanate to obtain surface-modified graphene oxide;

[0014] S22, surface modified graphene oxide reacts with silver nitrate to produce Ag + / graphene oxide;

[0015] Step 2: Mix the polyether polyol, chain extender, catalyst, pore opener, and deionized water, stir, and use the resulting mixture as material A;

[0016] Diisocyanate, composite flame retardant, Ag + / graphene oxide, ultrasonically dispersed, stirred, and the resulting mixed solution was used as material B;

[0017] Step 3: Mix material A and material B, inject into the mold, foam, demould, and mature to obtain polyurethane foam material.

[0018] Preferably, the S11 specifically includes:

[0019] Add pentaerythritol diphosphate diphosphoryl chloride to acetonitrile, heat to a first set temperature, dropwise add pentaerythritol solution, react, then heat to a second set temperature, continue to react, finally dropwise add triethylamine, react again, and after completion of the reaction, cool, filter, wash, and dry to obtain a phosphate ester;

[0020] The molar ratio of pentaerythritol diphosphate diphosphoryl chloride, pentaerythritol, and triethylamine in the pentaerythritol solution is 4:1:(4.2-4.8), the amount of acetonitrile added is 10-15 times the mass of pentaerythritol diphosphate diphosphoryl chloride, the pentaerythritol solution is prepared by pentaerythritol and toluene in a mass ratio of 1:(15-20), the reaction conditions are: reacting at a first set temperature for 1.5-2.5 hours, the first set temperature is 65-75°C, continuing the reaction conditions are: reflux reaction at a second set temperature for 4-6 hours under nitrogen protection, and the reaction conditions again are: reflux reaction at the second set temperature for 1.5-2.5 hours under nitrogen protection, and the second set temperature is 85-95°C.

[0021] Preferably, the pentaerythritol diphosphate diphosphoryl chloride in S11 is prepared by the following steps:

[0022] Pentaerythritol and phosphorus oxychloride are mixed and reacted, and after the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain pentaerythritol diphosphate diphosphoryl chloride;

[0023] The molar ratio of pentaerythritol to phosphorus oxychloride is 1:(5-6), and the reaction conditions are first reacting at a temperature of 75-85°C for 1.5-2.5 hours, and then reacting at a temperature of 105-115°C for 14-18 hours.

[0024] Preferably, the S12 specifically includes:

[0025] The phosphate ester is dissolved in acetonitrile, and a melamine solution is added dropwise. After the addition is complete, pyridine is added and reacted. After the reaction is complete, the mixture is cooled, filtered, washed, and dried to obtain a nitrogen-phosphorus flame retardant.

[0026] The molar ratio of melamine to pyridine in the phosphate ester and melamine solution is 1:4:(4.2-4.8), the amount of acetonitrile added is 20-30 times the mass of the phosphate ester, and the melamine solution is prepared by preparing melamine and pyridine in a mass ratio of 1:(10-15). The reaction conditions are as follows: first reacting at 75-85°C for 0.5-1.5h, then stirring at 300-500 r / min and heating to 100-110°C, maintaining the temperature at 100-110°C and reflux for 8-12h.

[0027] Preferably, the S13 specifically includes:

[0028] The epoxy-modified inorganic flame retardant is dispersed in benzene and ultrasonically dispersed to obtain an epoxy-modified inorganic flame retardant dispersion liquid. The nitrogen-phosphorus flame retardant and the epoxy-modified inorganic flame retardant dispersion liquid are added to acetonitrile for reaction. After the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain a composite flame retardant.

[0029] The mass ratio of epoxy modified inorganic flame retardant, benzene, nitrogen phosphorus flame retardant and acetonitrile is (6-10):(60-80):(30-40):(200-300), and the reaction conditions are reflux reaction at 80-90°C for 2-3h.

[0030] Preferably, the epoxy-modified inorganic flame retardant in S13 includes epoxy-modified aluminum hydroxide.

[0031] Preferably, the epoxy-modified aluminum hydroxide is prepared by the following steps:

[0032] Aluminum hydroxide, deionized water, and isopropyl alcohol were mixed and ultrasonically dispersed, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane (silane coupling agent KH560) was added to react. After the reaction was completed, the mixture was filtered, washed, and dried to obtain epoxy-modified aluminum hydroxide.

[0033] The mass ratio of aluminum hydroxide, deionized water, isopropanol, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 7.8:(100-200):(100-200):(23.6-25), and the reaction conditions are stirring at a speed of 300-400 r / min and a temperature of 70-90°C for 50-70 minutes.

[0034] Preferably, the S21 specifically includes:

[0035] Graphene oxide is added to N,N-dimethylformamide, and after ultrasonic dispersion, 4,4ˊ,4〞-triphenylmethane triisocyanate is added to react. After the reaction is completed, the reaction is filtered, washed, and dried to obtain surface-modified graphene oxide;

[0036] The mass ratio of graphene oxide, N,N-dimethylformamide and 4,4ˊ,4〞-triphenylmethane triisocyanate is 1:(80-120):(10-20), and the reaction conditions are 75-85° C. for 20-30 hours.

[0037] Preferably, the S22 specifically includes:

[0038] The surface modified graphene oxide was added to N,N-dimethylformamide, and after ultrasonic dispersion, silver nitrate was added, and after further ultrasonic dispersion, stirring, centrifugal washing, and drying were performed to obtain Ag. + / graphene oxide;

[0039] The mass ratio of surface-modified graphene oxide, N,N-dimethylformamide, and silver nitrate is 5:(800-900):(10-20), and the stirring conditions are stirring at a speed of 100-200 r / min and a temperature of 55-65° C. for 3.5-4.5 hours.

[0040] Preferably, in step 2:

[0041] When preparing material A, the mass ratio of polyether polyol, chain extender, catalyst, pore opener and deionized water is (100-120):(5-10):(1-3):(1-2):(3-6);

[0042] When preparing material B, diisocyanate, composite flame retardant, Ag + The mass ratio of graphene oxide to graphene oxide is (80-100):(3-5):(3-5).

[0043] Preferably, the polyether polyol comprises a mixture of polyoxypropylene glycol and polytetramethylene ether glycol;

[0044] The mass ratio of the polyoxypropylene glycol (PPG) to polytetramethylene glycol (PTMG) is (0.5-1.5):1;

[0045] The chain extender includes 1,4-butanediol;

[0046] The catalyst includes trimethyl hydroxyethyl bisaminoethyl ether;

[0047] The diisocyanate includes diphenylmethane diisocyanate.

[0048] Preferably, in step three, the mass ratio of material A to material B is 100:(130-150), and the aging condition is aging at room temperature for 48-72 hours.

[0049] The invention also discloses a polyurethane foam material prepared by adopting the above-mentioned method for preparing the polyurethane foam material.

[0050] An application of the polyurethane foam material as described above.

[0051] Preferably, the application of the polyurethane foam material includes application in automobile interior decoration.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] In the present invention, a composite flame retardant is prepared by combining nitrogen flame retardant components, phosphorus flame retardant components and inorganic flame retardant components, which can effectively improve the flame retardant properties of polyurethane foam. + Combined with graphene oxide, it can effectively improve the antibacterial properties of polyurethane foam;

[0054] In preparing the composite flame retardant, pentaerythritol reacts with phosphorus oxychloride to produce pentaerythritol diphosphate diphosphoryl chloride. The pentaerythritol diphosphate diphosphoryl chloride reacts with the hydroxyl group on the pentaerythritol molecule via the acyl chloride group at one end to obtain a phosphate ester with a branched structure. The phosphate ester reacts with melamine via the acyl chloride group at the other end of the pentaerythritol diphosphate diphosphoryl chloride molecule to produce a nitrogen-phosphorus flame retardant. The nitrogen-phosphorus flame retardant has high nitrogen and phosphorus content and good flame retardant effect. The epoxy group introduced by surface modification of the epoxy-modified inorganic flame retardant reacts with the amino group introduced by melamine into the nitrogen-phosphorus flame retardant molecule to produce the composite flame retardant, thereby achieving chemical bonding between the inorganic flame retardant and the nitrogen-phosphorus flame retardant. Since melamine has a unique conjugated triazine ring stable structure and three equipositional primary amino groups, it has considerable activity and can further react with isocyanate to connect the composite flame retardant to the polyurethane matrix via a stable chemical bond, resulting in good dispersion uniformity and high flame retardant performance.

[0055] Ag + / Graphene oxide is used as an antibacterial agent. Graphene oxide undergoes surface modification, and the isocyanate groups introduced participate in the reaction, connecting the antibacterial agent to the polyurethane matrix with a stable chemical bond, resulting in high and stable antibacterial properties.

[0056] Because the composite flame retardant has a branched structure and can react with isocyanate, the polyurethane molecules have a three-dimensional spatial structure, which makes the polyurethane foam have excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the structure of the nitrogen-phosphorus flame retardant prepared in the present invention;

[0058] Figure 2 This is a line graph showing the flame retardancy test results of the polyurethane foam materials prepared in Examples 3-5 of the present invention and Comparative Examples 1-3;

[0059] Figure 3 A line graph showing the antibacterial performance test results of the polyurethane foam materials prepared in Examples 3-5 of the present invention and Comparative Examples 1-3;

[0060] Figure 4 It is a line graph of the mechanical property test results of the polyurethane foam materials prepared in Examples 3-5 of the present invention and Comparative Examples 1-3. DETAILED DESCRIPTION

[0061] Example 1

[0062] This embodiment discloses a method for preparing pentaerythritol diphosphate diphosphoryl chloride, comprising the following steps:

[0063] Pentaerythritol and phosphorus oxychloride were mixed in a molar ratio of 1:5.5, and the mixture was reacted at 80°C for 2 hours and then at 110°C for 16 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed with chloroform, ethanol, and ether in sequence, and then dried in a vacuum drying oven at 50°C to constant weight to obtain pentaerythritol diphosphate diphosphoryl chloride.

[0064] Example 2

[0065] This embodiment discloses a method for preparing epoxy-modified aluminum hydroxide, comprising the following steps:

[0066] Aluminum hydroxide, deionized water, and isopropanol were mixed and ultrasonically dispersed at a frequency of 40 kHz for 30 minutes. Then, γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added. The mass ratio of aluminum hydroxide, deionized water, isopropanol, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane was 7.8:150:150:24. The mixture was stirred at a speed of 350 r / min and a temperature of 80°C for 60 minutes. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and then dried in a vacuum drying oven at 50°C to constant weight to obtain epoxy-modified aluminum hydroxide.

[0067] Example 3

[0068] This embodiment discloses a method for preparing a polyurethane foam material, comprising the following steps:

[0069] Step 1: Preparation of composite flame retardant and Ag + / graphene oxide

[0070] The preparation of the composite flame retardant comprises the following steps:

[0071] S11. Add pentaerythritol diphosphate diphosphoryl chloride to acetonitrile, heat to 65° C., add pentaerythritol solution dropwise for 1 hour, react at 65° C. for 2.5 hours, heat to 85° C., reflux at 85° C. for 6 hours under nitrogen protection, finally add triethylamine dropwise for 30 minutes, reflux at 85° C. for 2.5 hours under nitrogen protection, cool to room temperature after completion of the reaction, filter, wash the filter cake with acetonitrile, deionized water, and ethanol in sequence, and dry in a vacuum drying oven at 50° C. to constant weight to obtain phosphate;

[0072] The molar ratio of pentaerythritol diphosphate diphosphoryl chloride, pentaerythritol, and triethylamine in the pentaerythritol solution is 4:1:4.2, the amount of acetonitrile added is 10 times the mass of pentaerythritol diphosphate diphosphoryl chloride, and the pentaerythritol solution is prepared by preparing pentaerythritol and toluene in a mass ratio of 1:15;

[0073] Pentaerythritol diphosphate diphosphoryl chloride is the pentaerythritol diphosphate diphosphoryl chloride prepared in Example 1;

[0074] S12, phosphoric acid ester reacts with melamine to prepare nitrogen-phosphorus flame retardant;

[0075] The phosphate ester was dissolved in acetonitrile, and a melamine solution was added dropwise for 1 hour. After the addition was completed, pyridine was added, and the mixture was reacted at 75°C for 1.5 hours. The mixture was then heated to 100°C with stirring at a speed of 300 r / min, and the temperature was maintained at 100°C for reflux reaction for 12 hours. After the reaction was completed, the mixture was cooled to 0°C and filtered. The filter cake was washed with ethanol and dried in a vacuum drying oven at 50°C to constant weight to obtain a nitrogen-phosphorus flame retardant.

[0076] The molar ratio of melamine to pyridine in the phosphate ester and melamine solution is 1:4:4.2, the amount of acetonitrile added is 20 times the mass of the phosphate ester, and the melamine solution is prepared by mixing melamine and pyridine in a mass ratio of 1:10;

[0077] S13. Disperse epoxy-modified aluminum hydroxide in benzene and ultrasonically disperse at a frequency of 40 kHz for 30 minutes to obtain an epoxy-modified aluminum hydroxide dispersion. Add nitrogen-phosphorus flame retardant and epoxy-modified inorganic flame retardant dispersion to acetonitrile, wherein the mass ratio of epoxy-modified inorganic flame retardant, benzene, nitrogen-phosphorus flame retardant and acetonitrile is 6:60:30:200. Reflux at 80° C. for 3 hours. After the reaction is completed, cool to room temperature, filter, wash the filter cake with ethanol, and place it in a vacuum drying oven at 50° C. to dry to constant weight to obtain a composite flame retardant.

[0078] The epoxy-modified aluminum hydroxide is the epoxy-modified aluminum hydroxide prepared in Example 2;

[0079] Among them, Ag + / Preparation of graphene oxide, comprising the following steps:

[0080] S21, adding graphene oxide to N,N-dimethylformamide, ultrasonically dispersing at a frequency of 40 kHz for 30 minutes, adding 4,4ˊ,4〞-triphenylmethane triisocyanate, the mass ratio of graphene oxide, N,N-dimethylformamide, and 4,4ˊ,4〞-triphenylmethane triisocyanate being 1:80:10, and reacting at a temperature of 75°C for 30 hours. After the reaction is completed, filtering, washing the filter cake with N,N-dimethylformamide, and drying in a vacuum drying oven at 50°C to constant weight to obtain surface-modified graphene oxide;

[0081] S22, adding the surface-modified graphene oxide to N,N-dimethylformamide, ultrasonically dispersing it at a frequency of 40kHz for 30min, adding silver nitrate, the mass ratio of the surface-modified graphene oxide, N,N-dimethylformamide, and silver nitrate being 5:800:10, continuing ultrasonically dispersing it at a frequency of 40kHz for 30min, stirring it at a speed of 100r / min and a temperature of 55°C for 4.5h, washing it by centrifugation with ethanol 3 times, and drying it in a vacuum drying oven at 50°C to constant weight to obtain Ag + / graphene oxide;

[0082] Step 2: Mix polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water, and stir at a speed of 300 r / min at room temperature for 2 hours. The mass ratio of polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water is 100:5:1:1:3, and the resulting mixed solution is used as material A;

[0083] The polyether polyol is a mixture of polyoxypropylene glycol and polytetramethylene glycol in a mass ratio of 0.5:1.

[0084] Diphenylmethane diisocyanate, composite flame retardant, Ag + / graphene oxide mixture, diphenylmethane diisocyanate, composite flame retardant, Ag + The mass ratio of graphene oxide to graphene oxide was 80:3:3. After ultrasonic dispersion at a frequency of 40 kHz for 30 min, the mixture was stirred at a speed of 300 r / min at room temperature for 2 h. The obtained mixed solution was used as material B.

[0085] Step 3: Mix material A and material B with a mass ratio of material A to material B of 100:130, inject into a mold, foam, demould, and mature at room temperature for 48 hours to obtain a polyurethane foam material.

[0086] Example 4

[0087] This embodiment discloses a method for preparing a polyurethane foam material, comprising the following steps:

[0088] Step 1: Preparation of composite flame retardant and Ag + / graphene oxide

[0089] The preparation of the composite flame retardant comprises the following steps:

[0090] S11. Add pentaerythritol diphosphate diphosphoryl chloride to acetonitrile, heat to 65° C., add pentaerythritol solution dropwise for 2 hours, react at 75° C. for 1.5 hours, heat to 95° C., reflux at 95° C. for 4 hours under nitrogen protection, and finally add triethylamine dropwise for 50 minutes, reflux at 95° C. for 1.5 hours under nitrogen protection. After the reaction, cool to room temperature, filter, wash the filter cake with acetonitrile, deionized water, and ethanol in sequence, and dry in a vacuum drying oven at 50° C. to constant weight to obtain phosphate;

[0091] The molar ratio of pentaerythritol diphosphate diphosphoryl chloride, pentaerythritol, and triethylamine in the pentaerythritol solution is 4:1:4.8, the amount of acetonitrile added is 15 times the mass of pentaerythritol diphosphate diphosphoryl chloride, and the pentaerythritol solution is prepared by preparing pentaerythritol and toluene in a mass ratio of 1:20;

[0092] Pentaerythritol diphosphate diphosphoryl chloride is the pentaerythritol diphosphate diphosphoryl chloride prepared in Example 1;

[0093] S12, dissolving the phosphate ester in acetonitrile, adding the melamine solution dropwise, the melamine solution was added dropwise for 2 hours, and after the addition was completed, pyridine was added, first reacting at 75°C for 0.5 hours, then stirring at a speed of 500 r / min and heating to 110°C, maintaining the temperature at 110°C for 8 hours, and after the reaction was completed, cooling to 0°C, filtering, washing the filter cake with ethanol, and placing it in a vacuum drying oven at 50°C to constant weight to obtain a nitrogen-phosphorus flame retardant;

[0094] The molar ratio of melamine to pyridine in the phosphate ester and melamine solution is 1:4:4.8, the amount of acetonitrile added is 30 times the mass of the phosphate ester, and the melamine solution is prepared by mixing melamine and pyridine in a mass ratio of 1:15.

[0095] S13. Disperse epoxy-modified aluminum hydroxide in benzene and ultrasonically disperse at a frequency of 40 kHz for 30 minutes to obtain an epoxy-modified aluminum hydroxide dispersion. Add nitrogen-phosphorus flame retardant and epoxy-modified inorganic flame retardant dispersion to acetonitrile, wherein the mass ratio of epoxy-modified inorganic flame retardant, benzene, nitrogen-phosphorus flame retardant and acetonitrile is 10:80:40:300. Reflux at 90° C. for 2 hours. After the reaction is completed, cool to room temperature, filter, wash the filter cake with ethanol, and place it in a vacuum drying oven at 50° C. to dry to constant weight to obtain a composite flame retardant.

[0096] The epoxy-modified aluminum hydroxide is the epoxy-modified aluminum hydroxide prepared in Example 2;

[0097] Among them, Ag + / Preparation of graphene oxide, comprising the following steps:

[0098] S21, adding graphene oxide to N,N-dimethylformamide, ultrasonically dispersing at a frequency of 40 kHz for 30 minutes, adding 4,4ˊ,4〞-triphenylmethane triisocyanate, the mass ratio of graphene oxide, N,N-dimethylformamide, and 4,4ˊ,4〞-triphenylmethane triisocyanate being 1:120:20, and reacting at a temperature of 85°C for 20 hours. After the reaction is completed, filtering, washing the filter cake with N,N-dimethylformamide, and drying in a vacuum drying oven at 50°C to constant weight to obtain surface-modified graphene oxide;

[0099] S22, adding the surface-modified graphene oxide to N,N-dimethylformamide, ultrasonically dispersing it at a frequency of 40kHz for 30min, adding silver nitrate, the mass ratio of the surface-modified graphene oxide, N,N-dimethylformamide, and silver nitrate being 5:900:20, continuing ultrasonically dispersing it at a frequency of 40kHz for 30min, stirring it at a speed of 200r / min and a temperature of 65°C for 3.5h, washing it by centrifugation with ethanol 3 times, and drying it in a vacuum drying oven at 50°C to constant weight to obtain Ag + / graphene oxide;

[0100] Step 2: Mix polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water, and stir at a speed of 500 r / min at room temperature for 1 hour. The mass ratio of polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water is 120:10:3:2:6. The resulting mixed solution is used as material A;

[0101] The polyether polyol is a mixture of polyoxypropylene glycol and polytetramethylene glycol in a mass ratio of 1.5:1.

[0102] Diphenylmethane diisocyanate, composite flame retardant, Ag + / graphene oxide mixture, diphenylmethane diisocyanate, composite flame retardant, Ag + The mass ratio of graphene oxide to graphene oxide was 100:5:5. After ultrasonic dispersion at a frequency of 40 kHz for 30 min, the mixture was stirred at a speed of 500 r / min at room temperature for 3 h. The obtained mixed solution was used as material B.

[0103] Step 3: Mix material A and material B with a mass ratio of material A to material B of 100:150, inject into a mold, foam, demould, and mature at room temperature for 72 hours to obtain a polyurethane foam material.

[0104] Example 5

[0105] This embodiment discloses a method for preparing a polyurethane foam material, comprising the following steps:

[0106] Step 1: Preparation of composite flame retardant and Ag + / graphene oxide

[0107] The preparation of the composite flame retardant comprises the following steps:

[0108] S11. Add pentaerythritol diphosphate diphosphoryl chloride to acetonitrile, heat to 70°C, add pentaerythritol solution dropwise for 1.5 hours, react at 70°C for 2 hours, heat to 90°C, reflux at 90°C for 5 hours under nitrogen protection, finally add triethylamine dropwise for 40 minutes, reflux at 90°C for 2 hours under nitrogen protection, cool to room temperature after completion of the reaction, filter, wash the filter cake with acetonitrile, deionized water, and ethanol in sequence, and dry in a vacuum drying oven at 50°C to constant weight to obtain phosphate;

[0109] The molar ratio of pentaerythritol diphosphate diphosphoryl chloride, pentaerythritol, and triethylamine in the pentaerythritol solution is 4:1:4.5, the amount of acetonitrile added is 12 times the mass of pentaerythritol diphosphate diphosphoryl chloride, and the pentaerythritol solution is prepared by preparing pentaerythritol and toluene in a mass ratio of 1:18;

[0110] Pentaerythritol diphosphate diphosphoryl chloride is the pentaerythritol diphosphate diphosphoryl chloride prepared in Example 1;

[0111] S12, dissolving the phosphate ester in acetonitrile, adding the melamine solution dropwise for 2 hours, adding pyridine after the addition is complete, first reacting at 80°C for 1 hour, then stirring and heating to 105°C at a speed of 400 r / min, maintaining the temperature at 105°C for 10 hours, cooling to 0°C after the reaction, filtering, washing the filter cake with ethanol, and drying it in a vacuum drying oven at 50°C to constant weight to obtain a nitrogen-phosphorus flame retardant;

[0112] The molar ratio of melamine to pyridine in the phosphate ester and melamine solution is 1:4:4.5, the amount of acetonitrile added is 25 times the mass of the phosphate ester, and the melamine solution is prepared by mixing melamine and pyridine in a mass ratio of 1:12;

[0113] S13. Disperse epoxy-modified aluminum hydroxide in benzene and ultrasonically disperse at a frequency of 40 kHz for 30 minutes to obtain an epoxy-modified aluminum hydroxide dispersion. Add nitrogen-phosphorus flame retardant and epoxy-modified inorganic flame retardant dispersion to acetonitrile, wherein the mass ratio of epoxy-modified inorganic flame retardant, benzene, nitrogen-phosphorus flame retardant and acetonitrile is 8:70:35:250. Reflux at 85° C. for 2.5 hours. After the reaction is completed, cool to room temperature, filter, wash the filter cake with ethanol, and place it in a vacuum drying oven at 50° C. to dry to constant weight to obtain a composite flame retardant.

[0114] The epoxy-modified aluminum hydroxide is the epoxy-modified aluminum hydroxide prepared in Example 2;

[0115] Among them, Ag + / Preparation of graphene oxide, comprising the following steps:

[0116] S21, adding graphene oxide to N,N-dimethylformamide, ultrasonically dispersing at a frequency of 40 kHz for 30 minutes, adding 4,4ˊ,4〞-triphenylmethane triisocyanate, the mass ratio of graphene oxide, N,N-dimethylformamide, and 4,4ˊ,4〞-triphenylmethane triisocyanate being 1:100:15, reacting at a temperature of 80°C for 24 hours, filtering after completion of the reaction, washing the filter cake with N,N-dimethylformamide, and drying in a vacuum drying oven at 50°C to constant weight to obtain surface-modified graphene oxide;

[0117] S22, adding surface-modified graphene oxide to N,N-dimethylformamide, ultrasonically dispersing for 30 minutes at a frequency of 40kHz, adding silver nitrate, the mass ratio of surface-modified graphene oxide, N,N-dimethylformamide, and silver nitrate being 5:850:15, continuing ultrasonically dispersing for 30 minutes at a frequency of 40kHz, stirring at a speed of 150r / min and a temperature of 60°C for 4 hours, washing with ethanol by centrifugation 3 times, and drying in a vacuum drying oven at 50°C to constant weight to obtain Ag + / graphene oxide;

[0118] Step 2: Mix polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water, and stir at a speed of 400 r / min at room temperature for 1.5 hours. The mass ratio of polyether polyol, 1,4-butanediol, trimethyl hydroxyethyl bisaminoethyl ether, a pore opener, and deionized water is 110:8:2:1.5:4.5. The resulting mixed solution is used as material A;

[0119] The polyether polyol is a mixture of polyoxypropylene glycol and polytetramethylene glycol in a mass ratio of 1:1.

[0120] Diphenylmethane diisocyanate, composite flame retardant, Ag + / graphene oxide mixture, diphenylmethane diisocyanate, composite flame retardant, Ag + The mass ratio of graphene oxide to graphene oxide was 90:4:4. After ultrasonic dispersion at a frequency of 40 kHz for 30 min, the mixture was stirred at a speed of 400 r / min at room temperature for 2.5 h. The obtained mixed solution was used as material B.

[0121] Step 3: Mix material A and material B with a mass ratio of material A to material B of 100:140, inject into a mold, foam, demould, and mature at room temperature for 60 hours to obtain a polyurethane foam material.

[0122] Comparative Example 1

[0123] Compared with Example 3, in Comparative Example 1, when preparing Ag + / graphene oxide, the graphene oxide was not modified with 4,4ˊ,4〞-triphenylmethane triisocyanate, and other conditions remained unchanged.

[0124] Comparative Example 2

[0125] Compared with Example 3, in Comparative Example 2, the interaction between the nitrogen-phosphorus flame retardant and the inorganic flame retardant component aluminum hydroxide is replaced by physical mixing instead of chemical bonding, while other conditions remain unchanged.

[0126] Comparative Example 3

[0127] Compared with Example 3, in Comparative Example 3, the interaction between the nitrogen-based flame retardant component melamine, the phosphorus-based flame retardant component phosphate, and the inorganic flame retardant component aluminum hydroxide is replaced by physical mixing instead of chemical bonding, and other conditions remain unchanged.

[0128] In the above embodiments and comparative examples, aluminum hydroxide was purchased from Guangzhou Changyu Chemical Co., Ltd., brand: AH-1, particle size: 10000 mesh; graphene oxide was purchased from Shanghai Naio Nano Technology Co., Ltd., product number: NO-C-068-1, thickness: <2nm, diameter: 20μm; polyoxypropylene glycol was PPG1000, purchased from Tianjin Zhonghe Shengtai Chemical Co., Ltd.; polytetramethylene ether glycol was PTMG1000, purchased from Jiangsu Haolong Chemical Co., Ltd.; and the pore opener was purchased from Shanghai Yexing Industrial Co., Ltd., model: LK-204.

[0129] Test example

[0130] (1) Flame retardant properties: The polyurethane foam materials prepared in Examples 3-5 and Comparative Examples 1-2 were cut into samples of 120 mm × 10 mm × 10 mm, respectively. The oxygen index (OI) of the samples was tested according to the standard GB / T 2406.2-2009. The test results are shown in Table 1:

[0131] Table 1

[0132]

[0133] As shown in Table 1, the polyurethane foam material produced by the present invention exhibits excellent flame retardancy. The combination of nitrogen-based, phosphorus-based, and inorganic flame retardants in the present invention provides excellent flame retardancy. Furthermore, the graphene oxide in the antimicrobial component further enhances the polyurethane foam's flame retardancy by its charring and heat and smoke barrier properties. Compared with Example 3, in Comparative Example 1, the graphene oxide was not modified with 4,4′,4″-triphenylmethane triisocyanate, the dispersion uniformity between the graphene oxide and the polyurethane matrix was reduced, and the flame retardant properties were reduced; in Comparative Example 2, the inorganic flame retardant component aluminum hydroxide was not chemically bonded to the nitrogen-phosphorus flame retardant, the dispersion uniformity between the graphene oxide and the polyurethane matrix was reduced, and the flame retardant properties were also reduced; in Comparative Example 3, the nitrogen-based flame retardant component melamine and the phosphorus-based flame retardant component phosphate were not chemically bonded to the inorganic flame retardant component aluminum hydroxide, the dispersion uniformity between the phosphorus-based flame retardant component and the inorganic flame retardant component and the polyurethane matrix was reduced, and the flame retardant properties were further reduced on the basis of Comparative Example 2.

[0134] (2) Antibacterial performance: The polyurethane foam materials prepared in Examples 3-5 and Comparative Examples 1-2 were cut into samples of 10 mm × 10 mm and weighing 0.75 g. The antibacterial rates of the samples against Staphylococcus aureus, Escherichia coli, and Candida albicans were tested according to the reference standard GB20944.3-2008. The antibacterial rate was the ratio of the difference in the average colony count before and after shaking of the sample to the average colony count before shaking. The test results are shown in Table 2:

[0135] Table 2

[0136]

[0137] As shown in Table 2, the polyurethane foam material prepared in the present invention has good antibacterial properties. + Combined with graphene oxide, it can effectively improve the antibacterial properties of polyurethane foam. Compared with Example 3, in Comparative Example 1, graphene oxide was not modified with 4,4′,4″-triphenylmethane triisocyanate, and Ag + / The dispersion uniformity between graphene oxide and the polyurethane matrix is ​​reduced, and the antibacterial performance is reduced; in Comparative Examples 2 and 3, the flame retardant properties of the polyurethane foam material are mainly affected, and the antibacterial performance is not significantly affected.

[0138] (3) Mechanical properties: The polyurethane foam materials prepared in Examples 3-5 and Comparative Examples 1-2 were subjected to mechanical property tests. The compressive strength of the polyurethane foam materials was tested according to the reference standard GB / T8813-2020, and the tensile strength and elongation at break of the polyurethane foam materials were tested according to the reference standard GB9641-1988. The test results are shown in Table 3:

[0139] Table 3

[0140] Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Compression strength (kPa) 164 171 167 164 163 148 Tensile strength (kPa) 245 257 251 244 242 221 Elongation at break (%) 29 32 30 29 28 26

[0141] As shown in Table 3, the polyurethane foam material prepared in the present invention has excellent mechanical properties. The composite flame retardant prepared in the present invention has a branched structure and can react with isocyanate, giving the polyurethane molecules a three-dimensional spatial structure, thereby endowing the polyurethane foam with excellent mechanical properties. Compared with Example 3, in Comparative Example 1, the graphene oxide was not modified with 4,4ˊ,4"-triphenylmethane triisocyanate, which primarily affected the flame retardant and antibacterial properties of the polyurethane foam material and had no significant effect on the mechanical properties. In Comparative Example 2, although the inorganic flame retardant component aluminum hydroxide and the nitrogen-phosphorus flame retardant were not chemically bonded, the amino groups introduced into the melamine molecules still reacted with isocyanate, achieving a three-dimensional spatial structure for the polyurethane molecules, which did not significantly affect the mechanical properties of the polyurethane foam material. In Comparative Example 3, although the melamine reacted with isocyanate through the amino groups to crosslink the polyurethane molecules, giving them a three-dimensional spatial structure, the crosslinking effect was weakened compared to the composite flame retardant, resulting in a relatively simple structure and reduced mechanical properties.

[0142] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polyurethane foam material, characterized in that: The following steps are involved: Step 1: Preparation of composite flame retardant and Ag + / graphene oxide; The preparation of the composite flame retardant comprises the following steps: S11, pentaerythritol diphosphate diphosphoryl chloride and pentaerythritol to prepare a phosphate ester; S12, phosphoric acid ester reacts with melamine to prepare nitrogen-phosphorus flame retardant; S13, reacting the nitrogen-phosphorus flame retardant with the epoxy-modified inorganic flame retardant to prepare a composite flame retardant; Among them, Ag + / Preparation of graphene oxide, comprising the following steps: S21, reacting graphene oxide with polyisocyanate to obtain surface-modified graphene oxide; S22, surface modified graphene oxide reacts with silver nitrate to produce Ag + / graphene oxide; Step 2: Mix the polyether polyol, chain extender, catalyst, pore opener, and deionized water, stir, and use the resulting mixture as material A; Diisocyanate, composite flame retardant, Ag + / graphene oxide, ultrasonically dispersed, stirred, and the resulting mixed solution was used as material B; Step 3: Mix material A and material B, inject into the mold, foam, demould, and mature to obtain polyurethane foam material.

2. The method for preparing a polyurethane foam material according to claim 1, wherein: Said S11 specifically includes: Add pentaerythritol diphosphate diphosphoryl chloride to acetonitrile, heat to a first set temperature, dropwise add pentaerythritol solution, react, then heat to a second set temperature, continue to react, finally dropwise add triethylamine, react again, and after completion of the reaction, cool, filter, wash, and dry to obtain a phosphate ester; Among them, the molar ratio of pentaerythritol diphosphate diphosphoryl chloride, pentaerythritol, and triethylamine in the pentaerythritol solution is 4:1:(4.2-4.8), the reaction conditions are to react at a first set temperature for 1.5-2.5 hours, and the first set temperature is 65-75°C. The conditions for continuing the reaction are to reflux at a second set temperature for 4-6 hours under nitrogen protection, and the conditions for reacting again are to reflux at the second set temperature for 1.5-2.5 hours under nitrogen protection, and the second set temperature is 85-95°C.

3. The method for preparing a polyurethane foam material according to claim 1, wherein: Said S12 specifically includes: The phosphate ester is dissolved in acetonitrile, and a melamine solution is added dropwise. After the addition is complete, pyridine is added and reacted. After the reaction is complete, the mixture is cooled, filtered, washed, and dried to obtain a nitrogen-phosphorus flame retardant. The molar ratio of phosphate, melamine, and pyridine in the melamine solution is 1:4:(4.2-4.8). The reaction conditions are as follows: first react at 75-85°C for 0.5-1.5h, then stir and heat to 100-110°C at a speed of 300-500r / min, and maintain the temperature at 100-110°C for reflux reaction for 8-12h.

4. The method for preparing a polyurethane foam material according to claim 1, wherein: Said S13 specifically includes: The epoxy-modified inorganic flame retardant is dispersed in benzene and ultrasonically dispersed to obtain an epoxy-modified inorganic flame retardant dispersion liquid. The nitrogen-phosphorus flame retardant and the epoxy-modified inorganic flame retardant dispersion liquid are added to acetonitrile for reaction. After the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain a composite flame retardant. The mass ratio of epoxy modified inorganic flame retardant, benzene, nitrogen phosphorus flame retardant and acetonitrile is (6-10):(60-80):(30-40):(200-300), and the reaction conditions are reflux reaction at 80-90°C for 2-3h.

5. The method for preparing a polyurethane foam material according to claim 1, wherein: Said S21 specifically includes: Graphene oxide is added to N,N-dimethylformamide, and after ultrasonic dispersion, 4,4ˊ,4〞-triphenylmethane triisocyanate is added to react. After the reaction is completed, the reaction is filtered, washed, and dried to obtain surface-modified graphene oxide; The mass ratio of graphene oxide, N,N-dimethylformamide and 4,4ˊ,4〞-triphenylmethane triisocyanate is 1:(80-120):(10-20), and the reaction conditions are 75-85° C. for 20-30 hours.

6. The method for preparing a polyurethane foam material according to claim 1, wherein: Said S22 specifically includes: The surface modified graphene oxide was added to N,N-dimethylformamide, and after ultrasonic dispersion, silver nitrate was added, and after further ultrasonic dispersion, stirring, centrifugal washing, and drying were performed to obtain Ag. + / graphene oxide; The mass ratio of surface-modified graphene oxide, N,N-dimethylformamide, and silver nitrate is 5:(800-900):(10-20), and the stirring condition is 3.5-4.5 hours at a temperature of 55-65°C.

7. The method for preparing a polyurethane foam material according to claim 1, wherein: In the step 2: When preparing material A, the mass ratio of polyether polyol, chain extender, catalyst, pore opener and deionized water is (100-120):(5-10):(1-3):(1-2):(3-6); When preparing material B, diisocyanate, composite flame retardant, Ag + The mass ratio of graphene oxide to graphene oxide is (80-100):(3-5):(3-5).

8. The method for preparing a polyurethane foam material according to claim 1, wherein: In the step 3, the mass ratio of material A to material B is 100:(130-150), and the aging condition is aging at room temperature for 48-72 hours.

9. A polyurethane foam material prepared by the method for preparing a polyurethane foam material according to any one of claims 1 to 8.

10. Use of the polyurethane foam material according to claim 9.

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