Graphene oxide water-based chloride-free flame-retardant polyurethane microfiber leather and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane microfiber leather, and discloses graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather and a preparation method thereof. The preparation method comprises the following steps: carrying out reaction on p-aminoacetophenone, aniline, p-toluene sulfonic acid and DOPO, and adding graphene oxide, triethylamine and hexaaminocyclotriphosphazene for reaction to obtain a graphene oxide hybridized polysubstituted phosphazene polymer; then dispersing the graphene oxide and an amino silane coupling agent in alcohol water, and dropwise adding a phosphorus-containing water solution to obtain a graphene oxide water-based chlorine-free flame retardant; the preparation method comprises the following steps: preparing graphene oxide, mixing the graphene oxide with isophorone diisocyanate, polytetrahydrofuran ether glycol and the like to obtain a prepolymer, emulsifying in a dispersing agent to obtain an emulsion, adding an auxiliary agent, laminating with base cloth through a coating, curing and stripping to obtain the graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather disclosed by the invention has the characteristics of high flame-retardant efficiency and less harmful smoke in a combustion process, and also has excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane microfiber leather, and in particular to a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather and a preparation method thereof. Background Art

[0002] Polyurethane microfiber leather (synthetic leather) is widely used in clothing, furniture, automotive interiors and other fields due to its excellent mechanical properties, wear resistance and leather-like feel. However, its flammability (Limiting Oxygen Index LOI < 20%) and the release of toxic fumes (such as CO and HCN) during combustion have limited its application in high-end fields. Traditional flame retardant strategies mainly rely on chlorine-containing or bromine-containing (such as decabromodiphenyl ether) flame retardants, but these substances produce carcinogens such as dioxins when burned and have poor compatibility with polymers, resulting in a decrease in the mechanical properties of the material.

[0003] In recent years, chlorine-free flame retardant technology (such as phosphorus-nitrogen synergistic system) has become a research hotspot. Phosphazene compounds (such as hexaaminocyclotriphosphazene) have been widely studied due to their N / P flame retardant elements, high thermal stability and low toxicity. However, single phosphazene compounds have problems such as poor dispersibility and weak interfacial bonding with polymers. Graphene oxide (GO) has become an ideal hybrid filler due to its high specific surface area, mechanical strength and flame retardant enhancement effect (through physical barrier and catalytic carbonization). However, the agglomeration problem of GO in polymers and its interfacial compatibility with the organic phase still need to be solved.

[0004] Traditional solvent-based flame-retardant polyurethanes (PUs) suffer from high VOC emissions and severe environmental pollution. Waterborne polyurethanes (WPUs) use water as a dispersion medium, offering significant environmental advantages. However, their flame retardants must meet requirements for aqueous dispersion stability (e.g., particle size <500nm) and compatibility with isocyanates. Existing water-based flame retardants (e.g., ammonium polyphosphate) suffer from high water solubility (poor washability) and weak interfacial bonding with WPU (a >30% decrease in mechanical properties). Summary of the Invention

[0005] The purpose of the present invention is to provide a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather and a preparation method thereof, so as to solve the technical problems that the flame retardant effect of the existing single flame retardant system is limited and the flame retardant and mechanical properties of the polyurethane microfiber leather cannot be achieved at the same time.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, comprising the following steps:

[0008] (1) reacting p-aminoacetophenone, aniline, p-toluenesulfonic acid, and DOPO under a protective atmosphere, then adding graphene oxide, triethylamine, hexaaminocyclotriphosphazene, and an organic solvent, and performing a nucleophilic substitution reaction under a protective atmosphere to obtain a graphene oxide hybridized multi-substituted phosphazene polymer;

[0009] (2) mixing a graphene oxide hybridized multi-substituted phosphazene polymer, an aminosilane coupling agent, ethanol, and water, and then adding a phosphorus-containing aqueous solution dropwise to react to obtain a graphene oxide water-based chlorine-free flame retardant;

[0010] (3) mixing isophorone diisocyanate, polytetramethylene glycol, and dibutyltin dilaurate to perform a prepolymerization reaction, and then adding dimethylolpropionic acid and graphene oxide water-based chlorine-free flame retardant to obtain a prepolymer; mixing the prepolymer and a dispersant aqueous solution to emulsify and obtain an emulsion;

[0011] (4) mixing an emulsion, a thickener, a defoaming agent, a leveling agent, and a color paste to obtain a mixed emulsion; applying the mixed emulsion on the surface of a release paper, pre-drying the mixed emulsion, laminating the mixed emulsion with a base cloth, curing the mixed emulsion, and peeling off the release paper to obtain a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather.

[0012] Preferably, the dosage ratio of p-aminoacetophenone, aniline, p-toluenesulfonic acid, DOPO, triethylamine, hexaaminocyclotriphosphazene, graphene oxide, and organic solvent in step (1) is 1 g: 0.5-3 mL: 0.01-0.05 g: 0.5-5 g: 0.01-0.5 mL: 0.1-1 g: 0.1-1 g: 5-15 mL.

[0013] Preferably, the temperature of the reaction and the nucleophilic substitution reaction in step (1) are independently 100 to 150° C.; and the time of the reaction and the nucleophilic substitution reaction are independently 12 to 24 hours.

[0014] Preferably, the phosphorus-containing aqueous solution in step (2) is an aqueous solution of a phosphorus compound; the dosage ratio of the aminosilane coupling agent, the graphene oxide hybridized multi-substituted phosphazene polymer, ethanol, water, and the phosphorus compound in the phosphorus-containing aqueous solution is 1g:0.1-0.5g:0.5-5mL:3-10mL:0.1-1g.

[0015] Preferably, the reaction temperature in step (2) is 20-40° C., and the reaction time is 8-12 h.

[0016] Preferably, the mass ratio of isophorone diisocyanate, polytetramethylene ether glycol, dibutyltin dilaurate, dihydroxymethylpropionic acid, and graphene oxide water-based chlorine-free flame retardant in step (3) is 1:1-5:0.1-3:0.05-0.5:0.05-0.5.

[0017] Preferably, the mass ratio of the prepolymer to the dispersant aqueous solution in step (3) is 1:3-5; and the mass fraction of the dispersant in the dispersant aqueous solution is 0.1-10%.

[0018] Preferably, the temperature of the prepolymerization reaction in step (3) is 80-100° C.; the time of the prepolymerization reaction is 0.5-5 h; the speed of the emulsification is 1000-3000 rpm; and the time of the emulsification is 1-3 h.

[0019] Preferably, the mass ratio of the emulsion, thickener, defoamer, leveling agent and color paste in step (4) is 1:0.01-0.08:0.01-0.05:0.01-0.05:0.03-0.1.

[0020] The present invention also provides a method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, which produces a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather.

[0021] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) In the graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather of the present invention, GO nanosheets are combined with phosphazene polymers through covalent bonds (POC) and non-covalent interactions (π-π stacking), which improves the dispersibility and interfacial compatibility.

[0023] (2) In the graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather of the present invention, phosphorus-nitrogen-carbon (PNC) is used to synergistically replace chlorine-containing elements, and the toxicity of combustion smoke is reduced by >70%.

[0024] (3) In the water-based chlorine-free flame-retardant polyurethane microfiber leather of the present invention, the graphene oxide water-based chlorine-free flame retardant is modified with an aminosilane coupling agent to achieve stable dispersion of the graphene oxide water-based chlorine-free flame retardant in alcohol water, matching the reaction activity of isophorone diisocyanate (IPDI). DETAILED DESCRIPTION

[0025] The present invention provides a method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, comprising the following steps:

[0026] (1) reacting p-aminoacetophenone, aniline, p-toluenesulfonic acid, and DOPO under a protective atmosphere, then adding graphene oxide, triethylamine, hexaaminocyclotriphosphazene, and an organic solvent, and performing a nucleophilic substitution reaction under a protective atmosphere to obtain a graphene oxide hybridized multi-substituted phosphazene polymer;

[0027] (2) mixing a graphene oxide hybridized multi-substituted phosphazene polymer, an aminosilane coupling agent, ethanol, and water, and then adding a phosphorus-containing aqueous solution dropwise to react to obtain a graphene oxide water-based chlorine-free flame retardant;

[0028] (3) mixing isophorone diisocyanate, polytetramethylene glycol, and dibutyltin dilaurate to perform a prepolymerization reaction, and then adding dimethylolpropionic acid and graphene oxide water-based chlorine-free flame retardant to obtain a prepolymer; mixing the prepolymer and a dispersant aqueous solution to emulsify and obtain an emulsion;

[0029] (4) mixing an emulsion, a thickener, a defoaming agent, a leveling agent, and a color paste to obtain a mixed emulsion; applying the mixed emulsion on the surface of a release paper, pre-drying the mixed emulsion, laminating the mixed emulsion with a base cloth, curing the mixed emulsion, and peeling off the release paper to obtain a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather.

[0030] In the present invention, the dosage ratio of p-aminoacetophenone, aniline, p-toluenesulfonic acid, DOPO, triethylamine, hexaaminocyclotriphosphazene, graphene oxide, and organic solvent in step (1) is preferably 1 g: 0.5-3 mL: 0.01-0.05 g: 0.5-5 g: 0.01-0.5 mL: 0.1-1 g: 0.1-1 g: 5-15 mL, more preferably 1 g: 1-2 mL: 0.015-0.03 g: 1-3 g: 0.05-0.4 mL: 0.3-0.8 g: 0.2-0.6 g: 8-12 mL, and more preferably 1 g: 1.36 mL: 0.026 g: 1.6 g: 0.1 mL: 0.427 g: 0.328 g: 10 mL.

[0031] In the present invention, the protective atmosphere in step (1) is preferably a nitrogen atmosphere.

[0032] In the present invention, the reaction temperature in step (1) is preferably 100-150°C, more preferably 110-140°C, and more preferably 120°C; the reaction time is preferably 12-24h, more preferably 12-18h, and more preferably 12h.

[0033] In the present invention, the temperature of the nucleophilic substitution reaction in step (1) is preferably 100-150°C, more preferably 110-140°C, and more preferably 130°C; the time of the nucleophilic substitution reaction is preferably 12-24h, more preferably 12-18h, and more preferably 12h.

[0034] In the present invention, the organic solvent in step (1) is preferably N,N-dimethylformamide.

[0035] In the present invention, the aminosilane coupling agent in step (2) preferably comprises one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, and 3-aminopropylmethyldiethoxysilane, more preferably 3-aminopropyltrimethoxysilane or 3-aminopropylmethyldiethoxysilane, and more preferably 3-aminopropyltrimethoxysilane.

[0036] In the present invention, the phosphorus-containing aqueous solution in step (2) is preferably an aqueous solution of a phosphorus compound; the phosphorus compound preferably comprises one or more of hypophosphorous acid, phenyl hypophosphorous acid, and methyl hypophosphorous acid, further preferably hypophosphorous acid or methyl hypophosphorous acid, and more preferably hypophosphorous acid.

[0037] In the present invention, the amount ratio of the aminosilane coupling agent, graphene oxide hybridized multi-substituted phosphazene polymer, ethanol, water, and phosphorus compound in the phosphorus-containing aqueous solution in step (2) is preferably 1g:0.1-0.5g:0.5-5mL:3-10mL:0.1-1g, more preferably 1g:0.15-0.3g:2-5mL:6-10mL:0.2-0.7g, and more preferably 1g:0.2g:5mL:10mL:0.3g.

[0038] In the present invention, the reaction temperature in step (2) is preferably 20-40°C, more preferably 23-30°C, and more preferably 25°C; the reaction time is preferably 8-12h, more preferably 9-11h, and more preferably 10h.

[0039] In the present invention, the mass ratio of isophorone diisocyanate, polytetramethylene ether glycol, dibutyltin dilaurate, dimethylolpropionic acid, and graphene oxide water-based chlorine-free flame retardant in step (3) is preferably 1:1-5:0.1-3:0.05-0.5:0.05-0.5, more preferably 1:2-4:0.5-2:0.1-0.2:0.1-0.3, and more preferably 1:2.73:0.82:0.14:0.11.

[0040] In the present invention, the mass ratio of the prepolymer to the dispersant aqueous solution in step (3) is preferably 1:3-5, more preferably 1:3-4, and even more preferably 1:3.

[0041] In the present invention, the mass fraction of the dispersant in the dispersant aqueous solution in step (3) is preferably 0.1 to 10%, more preferably 0.1 to 2%, and more preferably 0.3%; the dispersant is preferably sodium hexametaphosphate.

[0042] In the present invention, the temperature of the prepolymerization reaction in step (3) is preferably 80-100°C, more preferably 85-95°C, and more preferably 90°C; the time of the prepolymerization reaction is preferably 0.5-5h, more preferably 0.5-3h, and more preferably 1h.

[0043] In the present invention, the emulsification in step (3) is preferably carried out in a high-speed emulsifier; the emulsification speed is preferably 1000-3000 rpm, more preferably 1200-2000 rpm, and more preferably 1500 rpm; the emulsification time is preferably 1-3 h, more preferably 2-3 h, and more preferably 2.5 h.

[0044] In the present invention, the mass ratio of the emulsion, thickener, defoamer, leveling agent and color paste in step (4) is preferably 1: 0.01-0.08: 0.01-0.05: 0.01-0.05: 0.03-0.1, more preferably 1: 0.02-0.07: 0.01-0.03: 0.01-0.03: 0.04-0.1, and more preferably 1: 0.02: 0.01: 0.01: 0.04.

[0045] In the present invention, the thickener, defoamer, leveling agent, and color paste described in step (4) are all commercially available products. The present invention does not limit the sources, and commercially available products purchased by those skilled in the art are sufficient. Specifically, in the embodiment, the thickener, defoamer, leveling agent, and color paste used were purchased from Guangdong Nanhui New Materials Co., Ltd. for water-based polyurethane thickener, Shandong Juneng Chemical Co., Ltd. for solid organosilicon defoamer, Nantong Hantai Chemical Co., Ltd. for polyurethane leveling agent HT-880, and Zhejiang Dabang Polyurethane Co., Ltd. for water-based polyurethane color paste.

[0046] In the present invention, the pre-drying temperature in step (4) is preferably 100° C.; the pre-drying time is preferably 5 minutes.

[0047] In the present invention, the base fabric in step (4) is preferably a needle-punched non-woven fabric, and more preferably a microfiber needle-punched non-woven fabric.

[0048] In the present invention, the lamination temperature in step (4) is preferably 100° C.; and the lamination time is preferably 90 s.

[0049] In the present invention, the aging temperature in step (4) is preferably 120° C.; and the aging time is preferably 8 minutes.

[0050] In this invention, the design of a graphene oxide-phosphazene hybrid flame retardant and aqueous interface synergistic technology achieves the advantages of polyurethane microfiber leather, including high flame retardancy, high mechanical strength, and environmental friendliness. Within the flame-retardant material system, GO and phosphazene polymers form a highly effective flame-retardant barrier through a multi-scale synergistic mechanism. The two-dimensional GO nanosheets act as a physical barrier, forming a "thermal barrier coating" that reduces thermal conductivity by delaying heat transfer, ultimately achieving highly effective flame retardant protection at high temperatures.

[0051] The present invention also provides a method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, which produces a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather.

[0052] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0053] Example 1

[0054] (1) 10.0 g of p-aminoacetophenone, 13.6 mL of aniline, 0.26 g of p-toluenesulfonic acid, and 16.0 g of DOPO were reacted at 120°C for 12 h under nitrogen protection. After the reaction, 1.0 mL of triethylamine, 4.27 g of hexaaminocyclotriphosphazene, and 3.28 g of graphene oxide were ultrasonically dispersed in 100 mL of N,N-dimethylformamide and then directly added to the reaction system. The mixture was reacted at 130°C for 12 h under nitrogen protection. After the reaction, the mixture was filtered, washed, and vacuum-dried at 50°C to obtain a graphene oxide hybridized multi-substituted phosphazene polymer, which was recorded as the target product S1.

[0055] (2) At room temperature (25°C), 10.0 g of 3-aminopropyltrimethoxysilane and 2.0 g of the target product S1 were dissolved in 100 mL of deionized water and 50 mL of anhydrous ethanol. 10.0 mL of an aqueous hypophosphorous acid solution (containing 3.0 g of hypophosphorous acid) was added dropwise while stirring. After the addition was complete, the mixture was stirred at room temperature (25°C) for 10 h. After drying, a water-based chlorine-free flame retardant of graphene oxide was obtained, which was recorded as the target product S2.

[0056] (3) 44.0 g of isophorone diisocyanate, 120.0 g of polytetramethylene glycol, and 36.0 g of dibutyltin dilaurate were prepolymerized at 90° C. for 1 h, and 6.0 g of dimethylolpropionic acid and 5.0 g of the target product S2 were mixed to obtain a prepolymer; 200.0 g of the prepolymer was dispersed in 600.0 g of a 0.3% aqueous solution of sodium hexametaphosphate and emulsified at 1500 rpm for 2.5 h to obtain an emulsion S3;

[0057] (4) Add 10.0 g of thickener, 5.0 g of defoaming agent, 5.0 g of leveling agent and 20.0 g of color paste to 500.0 g of emulsion S3 and stir evenly to obtain a mixed emulsion; apply the mixed emulsion on the surface of release paper and pre-bake at 100 ° C for 5 min to obtain a coating; laminate it with a microfiber needle-punched non-woven fabric base cloth at 100 ° C for 90 s, mature it at 120 ° C for 8 min, peel off the release paper, and obtain graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, which is recorded as PU MF-1.

[0058] Example 2

[0059] The difference between this embodiment and embodiment 1 is that in step (2), 3-aminopropyltrimethoxysilane is replaced by 3-aminopropyltriethoxysilane. For other details, refer to embodiment 1. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-2.

[0060] Example 3

[0061] The difference between this embodiment and embodiment 1 is that in step (2), 3-aminopropyltrimethoxysilane is replaced by 3-aminopropylmethyldimethoxysilane. For other details, refer to embodiment 1. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-3.

[0062] Example 4

[0063] The difference between this embodiment and embodiment 1 is that in step (2), 3-aminopropyltrimethoxysilane is replaced by 3-aminopropylmethyldiethoxysilane. For other details, refer to embodiment 1. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-4.

[0064] Example 5

[0065] The difference between this embodiment and embodiment 1 is that: in step (2), hypophosphorous acid is replaced by phenyl hypophosphorous acid, and the rest is referred to embodiment 1. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-5.

[0066] Example 6

[0067] The difference between this embodiment and embodiment 2 is that: in step (2), hypophosphorous acid is replaced by phenyl hypophosphorous acid, and the rest is referred to embodiment 2. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-6.

[0068] Example 7

[0069] The difference between this embodiment and embodiment 3 is that: in step (2), hypophosphorous acid is replaced by phenyl hypophosphorous acid, and the rest is referred to embodiment 3. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-7.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 4 is that: in step (2), hypophosphorous acid is replaced by phenyl hypophosphorous acid, and the rest is referred to embodiment 4. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-8.

[0072] Example 9

[0073] The difference between this embodiment and embodiment 1 is that: in step (2), hypophosphorous acid is replaced by methyl hypophosphorous acid, and the rest is referred to embodiment 1. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-9.

[0074] Example 10

[0075] The difference between this embodiment and embodiment 2 is that: in step (2), hypophosphorous acid is replaced by methyl hypophosphorous acid, and the rest is referred to embodiment 2. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-10.

[0076] Example 11

[0077] The difference between this embodiment and embodiment 3 is that: in step (2), hypophosphorous acid is replaced by methyl hypophosphorous acid, and the rest is referred to embodiment 3. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-11.

[0078] Example 12

[0079] The difference between this embodiment and embodiment 4 is that: in step (2), hypophosphorous acid is replaced by methyl hypophosphorous acid, and the rest is referred to embodiment 4. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather finally obtained is recorded as PU MF-12.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 1 is that it does not contain steps (1) and (2), and the target product S2 is not added in step (3). For other details, refer to Example 1. That is, this comparative example does not contain graphene oxide water-based chlorine-free flame retardant, and the finally obtained water-based polyurethane microfiber leather is recorded as PU MF-0.

[0082] According to GB / T 5455-2014 "Textile combustion performance test vertical method", GBT 5454-1997 "Textile combustion performance test oxygen index method" and GB / T 1040 "Determination of tensile properties of plastics", the graphene oxide water-based chlorine-free flame retardant polyurethane microfiber leather of Examples 1 to 12 and the water-based polyurethane microfiber leather of Comparative Example 1 were performance tested, and the results are shown in Table 1.

[0083] Table 1 Performance test results of samples of Examples 1 to 12 and Comparative Example 1

[0084]

[0085]

[0086] As shown in Table 1, the waterborne polyurethane microfiber leather composite prepared with the addition of graphene oxide waterborne chlorine-free flame retardant meets the flame retardancy V-0 requirement, a level that is sufficient for a wide range of applications. The composite also exhibits enhanced tensile strength, indicating a strong bond between the graphene oxide flame retardant and the waterborne polyurethane.

[0087] As can be seen from the above examples, the present invention provides a method for preparing a water-based chlorine-free flame-retardant polyurethane microfiber leather made of graphene oxide. First, p-aminoacetophenone, aniline, p-toluenesulfonic acid, and DOPO are subjected to a Schiff base reaction and an addition reaction. After adding graphene oxide, triethylamine, and hexaaminocyclotriphosphazene, a nucleophilic substitution reaction is carried out to obtain a graphene oxide hybridized multi-substituted phosphazene polymer. Then, it is dispersed in alcohol water with an aminosilane coupling agent at room temperature. A phosphorus-containing inorganic acid or organic acid aqueous solution is added dropwise during stirring. After the reaction is completed and dried, a water-based chlorine-free flame retardant made of graphene oxide is obtained. The prepolymer is then mixed with isophorone diisocyanate, polytetramethylene ether glycol, dibutyltin dilaurate, and dimethylolpropionic acid to obtain a prepolymer, which is emulsified in a dispersant to obtain a graphene oxide water-based chlorine-free flame-retardant polyurethane emulsion. A certain amount of thickener, defoamer, leveling agent, color paste, etc. are then added. The coating is then laminated to a base fabric, aged, and peeled off to obtain a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather. The graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather of the present invention has the characteristics of high flame retardant efficiency, low harmful smoke during combustion, and excellent mechanical properties.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather, characterized in that: The following steps are involved: (1) reacting p-aminoacetophenone, aniline, p-toluenesulfonic acid, and DOPO under a protective atmosphere, then adding graphene oxide, triethylamine, hexaaminocyclotriphosphazene, and an organic solvent, and performing a nucleophilic substitution reaction under a protective atmosphere to obtain a graphene oxide hybridized multi-substituted phosphazene polymer; (2) mixing a graphene oxide hybridized multi-substituted phosphazene polymer, an aminosilane coupling agent, ethanol, and water, and then adding a phosphorus-containing aqueous solution dropwise to react to obtain a graphene oxide water-based chlorine-free flame retardant; (3) mixing isophorone diisocyanate, polytetramethylene glycol, and dibutyltin dilaurate to perform a prepolymerization reaction, and then adding dimethylolpropionic acid and graphene oxide water-based chlorine-free flame retardant to obtain a prepolymer; mixing the prepolymer and a dispersant aqueous solution to emulsify and obtain an emulsion; (4) mixing an emulsion, a thickener, a defoaming agent, a leveling agent, and a color paste to obtain a mixed emulsion; applying the mixed emulsion on the surface of a release paper, pre-drying the mixed emulsion, laminating the mixed emulsion with a base cloth, curing the mixed emulsion, and peeling off the release paper to obtain a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather.

2. A method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 1, characterized in that, The dosage ratio of the p-aminoacetophenone, aniline, p-toluenesulfonic acid, DOPO, triethylamine, hexaaminocyclotriphosphazene, graphene oxide, and organic solvent in step (1) is 1 g: 0.5-3 mL: 0.01-0.05 g: 0.5-5 g: 0.01-0.5 mL: 0.1-1 g: 0.1-1 g: 5-15 mL.

3. A method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 2, characterized in that, The temperature of the reaction and the nucleophilic substitution reaction in step (1) are independently 100 to 150° C.; the time of the reaction and the nucleophilic substitution reaction are independently 12 to 24 hours.

4. A method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 3, characterized in that, The phosphorus-containing aqueous solution in step (2) is an aqueous solution of a phosphorus compound; the dosage ratio of the aminosilane coupling agent, the graphene oxide hybridized multi-substituted phosphazene polymer, ethanol, water, and the phosphorus compound in the phosphorus-containing aqueous solution is 1g:0.1-0.5g:0.5-5mL:3-10mL:0.1-1g.

5. A method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 1 or 4, characterized in that, The reaction temperature in step (2) is 20-40° C.; the reaction time is 8-12 h.

6. A method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 5, characterized in that, The mass ratio of the isophorone diisocyanate, polytetramethylene ether glycol, dibutyltin dilaurate, dihydroxymethylpropionic acid, and graphene oxide water-based chlorine-free flame retardant in step (3) is 1:1-5:0.1-3:0.05-0.5:0.05-0.

5.

7. A method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 6, characterized in that, The mass ratio of the prepolymer and the dispersant aqueous solution in step (3) is 1:3-5; the mass fraction of the dispersant in the dispersant aqueous solution is 0.1-10%.

8. A method for preparing graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 7, characterized in that, The temperature of the prepolymerization reaction in step (3) is 80-100° C.; the time of the prepolymerization reaction is 0.5-5 h; the speed of the emulsification is 1000-3000 rpm; and the time of the emulsification is 1-3 h.

9. A method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to claim 7, characterized in that, The mass ratio of the emulsion, thickener, defoamer, leveling agent and color paste in step (4) is 1:0.01-0.08:0.01-0.05:0.01-0.05:0.03-0.

1.

10. A graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather prepared by the method for preparing a graphene oxide water-based chlorine-free flame-retardant polyurethane microfiber leather according to any one of claims 1 to 9.

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