Intrinsic flame-retardant solvent-free polyurethane for automotive trim water-based PU leather and preparation method of intrinsic flame-retardant solvent-free polyurethane

Abstract

The invention discloses intrinsic flame-retardant solvent-free polyurethane for automotive trim water-based PU leather and a preparation method of the intrinsic flame-retardant solvent-free polyurethane, and relates to the technical field of solvent-free full-water-based PU leather, the intrinsic flame-retardant solvent-free polyurethane comprises a hydroxyl component, an isocyanate component and a catalyst component, and the mass ratio of the hydroxyl component to the isocyanate component to the catalyst component is 100: (40-120): (0.3-1.0); wherein the hydroxyl component comprises an amine chain extender, flame-retardant polyol and an auxiliary agent; according to the present invention, the peeling strength, the hydrolysis resistance, the low temperature resistance and the good flame retardation performance of the intrinsic flame retardation solvent-free polyurethane AB material of the polycarbonate system can be substantially the same level, and the aqueous polyurethane surface layer can be well attached to the aqueous polyurethane surface layer.

Description

Technical Field

[0001] The invention belongs to the technical field of solvent-free all-water-based PU leather, and specifically relates to an intrinsic flame-retardant solvent-free polyurethane for automobile interior water-based PU leather and a preparation method thereof. Background Art

[0002] As a kind of simulated leather, PU leather for automobile interior is widely used in automobile seats, door panels and decorative parts for its excellent physical properties, wear resistance, aging resistance and comfort. However, most of the PU leather on the market currently uses solvent-based polyurethane resin as the matrix, which releases harmful gases such as benzene, toluene and formaldehyde during production and use. The serious excess of the standard causes nearly 90% of cars to fail to meet the indoor air quality standards, posing a potential threat to human health. In order to solve this problem, the state has issued the national standard "Guidelines for Passenger Car Indoor Air Quality Evaluation", and it is expected that the national legislation will be enforced. At the same time, each OEM has also increased the monitoring of in-car air quality and issued its own control standards for VOC and TVOC.

[0003] Compared with solvent-based PU leather, water-based PU leather has lower VOC emissions, a safer production environment and healthier indoor air quality, while maintaining excellent physical properties and comfort. However, the existing intrinsic flame-retardant solvent-free polyurethane AB materials have problems such as poor peel strength, high cost and poor wet heat aging performance when bonding the water-based polyurethane surface layer and the water-based PU leather base fabric, and the general flame retardant performance cannot meet the higher safety requirements of automotive interiors.

[0004] At present, there are two types of polyurethane resins used in PU leather for automotive interiors on the market: solvent-based and solvent-free. Solvent-based polyurethane resins use organic solvents as reaction media and diluents. Although they have low costs, simple processes, and excellent performance, they have problems such as environmental pollution, safety hazards, and solvent residues, which seriously threaten human health and the natural environment. Solvent-free polyurethane resins do not require the use of organic solvents and have the advantages of being environmentally friendly, safe, and free of solvent residues. However, they have high costs, complex processes, unstable performance, and poor compatibility with existing adhesive layer materials, which limits their application in the field of automotive interiors. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems and provide an intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather and a preparation method thereof, which at least partially solves the above problems.

[0006] The technical solution adopted by the present invention is: an intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather, comprising a hydroxyl component, an isocyanate component, and a catalyst component, wherein the mass ratio of the hydroxyl component, the isocyanate component, and the catalyst component is 100:40-120:0.3-1.0; Wherein, the hydroxyl component includes an amine chain extender, a flame retardant polyol, and an auxiliary agent.

[0007] Furthermore, the hydroxyl component includes the following materials in proportion by weight: 90-110 parts of polyether polyol, 1.5-10 parts of chain extender, 10-30 parts of flame retardant polyol, and 2-10 parts of auxiliary agent.

[0008] Furthermore, the isocyanate-based component includes the following materials in proportion by weight: 450-600 parts of polyether polyol, 1-10 parts of amine chain extender, 10-30 parts of flame retardant polyol, 0.01-0.05 parts of inhibitor, and 300-500 parts of isocyanate.

[0009] Furthermore, the amine chain extender is a mixture of one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, liquid 3,3'-dichloro-4,4'-diaminodiphenylmethane modified with formaldehyde, ethylenediamine, and N,N-dihydroxy(diisopropyl)aniline.

[0010] Furthermore, the polyether polyol is a mixture of one or more of polyethylene oxide polyol, polypropylene oxide polyol and polytetramethylene oxide polyol; Wherein, the number average molecular weight of the polyether polyol is 800-4000.

[0011] Further, the catalyst includes an organic metal catalyst and an amine catalyst; Wherein, the mass ratio of the organic metal catalyst to the amine catalyst is 1:20-30; The organic metal catalyst is a mixture of one or more of organic bismuth and dibutyltin dilaurate; The amine catalyst is a mixture of one or more of triethylenediamine, tetramethyldiethylenetriamine, and 2,2-dimorpholinyldiethyl ether.

[0012] Furthermore, the isocyanate is a mixture of one or more of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, p-phenylenediisocyanate, and tetramethyldimethylene diisocyanate.

[0013] Furthermore, the auxiliary agent is a mixture of one or both of a silane coupling agent and an epoxy resin; The chain extender is a mixture of one or more of ethylene glycol, propylene glycol and 1,4-butanediol; The polymerization inhibitor is an acidic substance capable of providing active hydrogen, including but not limited to a mixture of one or more of phosphoric acid, hypophosphorous acid, hydroquinone, erucic acid, benzoic acid, and citric acid.

[0014] On the other hand, the present invention also provides a method for preparing an intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather, comprising the following steps: Preparation of isocyanate-based component: isocyanate and polymerization inhibitor are stirred in a reaction kettle at 45-55° C. for 5-30 minutes, and then polyether polyol and flame retardant polyol are added, and reacted at 70-75° C. for 2-4 hours to obtain the isocyanate-based component; Preparation of hydroxyl component: drying the polyether polyol at 100-120° C. under vacuum conditions for 1-2 hours to obtain a polyether polyol having a moisture content of less than 0.05%; The flame retardant polyol, the chain extender and the auxiliary agent are added and mixed uniformly to obtain a hydroxyl component.

[0015] On the other hand, the present invention also proposes a use of an intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather, wherein the intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather is used for the middle layer of the all-water-based PU leather, the hydroxyl component, the isocyanate component and the catalyst component are mixed in a mass ratio of 100:40-120:0.3-1.0, and coated on a release paper coated with a water-based polyurethane surface layer in a coating amount of 18 to 22 strands, and then dried and matured in an oven at 100-130°C, the semi-dried resin is bonded to the base cloth, and the release paper is peeled off after aging to obtain the solvent-free polyurethane all-water-based PU leather; The intrinsic flame-retardant solvent-free polyurethane for water-based PU leather for automobile interior decoration can be used without foaming or after foaming.

[0016] The beneficial effects of the present invention are: The intrinsic flame-retardant solvent-free polyurethane AB material for all-water PU leather of the present invention is composed of an isocyanate component, a hydroxyl component and a catalyst component. By adopting a polyurethane material in combination with a specific amine chain extender, a flame-retardant polyol and a coupling agent in the hydroxyl component, the intrinsic flame-retardant solvent-free polyurethane AB material of the present invention can achieve substantially the same level of peel strength, hydrolysis resistance and low temperature resistance as the intrinsic flame-retardant solvent-free polyurethane AB material of a polycarbonate system, has better flame-retardant properties, and can better adhere to a waterborne polyurethane surface layer. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0018] At present, there are two types of polyurethane resins used in PU leather for automotive interiors on the market: solvent-based and solvent-free. Solvent-based polyurethane resins use organic solvents as reaction media and diluents. Although they have low costs, simple processes, and excellent performance, they have problems such as environmental pollution, safety hazards, and solvent residues, which seriously threaten human health and the natural environment. Solvent-free polyurethane resins do not require the use of organic solvents and have the advantages of being environmentally friendly, safe, and free of solvent residues. However, they have high costs, complex processes, unstable performance, and poor compatibility with existing adhesive layer materials, which limits their application in the field of automotive interiors.

[0019] The present invention aims to solve the problems of poor bonding strength, high cost, insufficient flame retardant performance, etc. of existing solvent-free polyurethane, and provides an intrinsic flame retardant solvent-free polyurethane AB material and a preparation method thereof. The AB material adopts solvent-free polyurethane resin, combined with special formula design and preparation process, to achieve excellent bonding strength, hydrolysis resistance and flame retardant performance, while maintaining low cost, providing an ideal solution for PU leather for automotive interior.

[0020] Therefore, the present invention provides an intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather, comprising a hydroxyl component, an isocyanate component, and a catalyst component, wherein the mass ratio of the hydroxyl component, the isocyanate component, and the catalyst component is 100:40-120:0.3-1.0; Wherein, the hydroxyl component includes an amine chain extender, a flame retardant polyol, and an auxiliary agent.

[0021] Preferably, the mass ratio of the hydroxyl component, the isocyanate component and the catalyst component is 100:120:0.6.

[0022] By adopting polyurethane materials to replace the polycarbonate materials in the prior art, and combining specific amine chain extenders, flame retardant polyols and additives in the hydroxyl component, the intrinsic flame retardant solvent-free polyurethane AB material can have better flame retardant properties and can better fit the water-based polyurethane surface layer on the premise of basically the same level of peel strength, hydrolysis resistance and low temperature resistance.

[0023] In a further implementation of this example, the hydroxyl component includes the following materials in proportion by weight: 90-110 parts of polyether polyol, 1.5-10 parts of chain extender, 10-30 parts of flame retardant polyol, and 2-10 parts of auxiliary agent.

[0024] In a further embodiment of this example, the isocyanate-based component includes the following materials in proportion by weight: 450-600 parts of polyether polyol, 1-10 parts of amine chain extender, 10-30 parts of flame retardant polyol, 0.01-0.05 parts of inhibitor, and 300-500 parts of isocyanate.

[0025] In a further embodiment of this example, the amine chain extender is a mixture of one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, liquid 3,3'-dichloro-4,4'-diaminodiphenylmethane modified with formaldehyde, ethylenediamine, and N,N-dihydroxy(diisopropyl)aniline.

[0026] In a further embodiment of this example, the polyether polyol is a mixture of one or more of polyethylene oxide polyol, polypropylene oxide polyol, and polytetramethylene glycol polyol; Wherein, the number average molecular weight of the polyether polyol is 800-4000.

[0027] In a further embodiment of this example, the catalyst includes an organic metal catalyst and an amine catalyst; Wherein, the mass ratio of the organic metal catalyst to the amine catalyst is 1:20-30; The organic metal catalyst is a mixture of one or more of organic bismuth and dibutyltin dilaurate; The amine catalyst is a mixture of one or more of triethylenediamine, tetramethyldiethylenetriamine, and 2,2-dimorpholinyldiethyl ether.

[0028] In a further embodiment of this example, the isocyanate is a mixture of one or more of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, p-phenylenediisocyanate, and tetramethyldimethylene diisocyanate.

[0029] In a further implementation of this embodiment, the auxiliary agent is a mixture of one or both of a silane coupling agent and an epoxy resin; The chain extender is a mixture of one or more of ethylene glycol, propylene glycol and 1,4-butanediol; The polymerization inhibitor is an acidic substance capable of providing active hydrogen, including but not limited to a mixture of one or more of phosphoric acid, hypophosphorous acid, hydroquinone, erucic acid, benzoic acid, and citric acid.

[0030] On the other hand, an embodiment of the present invention also provides a method for preparing an intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather, comprising the following steps: Preparation of isocyanate-based component: isocyanate and polymerization inhibitor are stirred in a reaction kettle at 45-55° C. for 5-30 minutes, and then polyether polyol and flame retardant polyol are added, and reacted at 70-75° C. for 2-4 hours to obtain the isocyanate-based component; Preparation of hydroxyl component: drying the polyether polyol at 100-120° C. under vacuum conditions for 1-2 hours to obtain a polyether polyol having a moisture content of less than 0.05%; The flame retardant polyol, chain extender and auxiliary agent are added and mixed uniformly to obtain a hydroxyl component.

[0031] On the other hand, the embodiment of the present invention further proposes a use of an intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather, wherein the intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather is used for the middle layer of the fully water-based PU leather, and the hydroxyl component, the isocyanate component and the catalyst component are mixed in a mass ratio of 100:40-120:0.3-1.0, and coated on a release paper coated with a water-based polyurethane surface layer in a coating amount of 18 to 22 strands, and then dried and matured in an oven at 100-130°C, and the semi-dried resin is bonded to the base cloth, and the release paper is peeled off after aging to obtain a solvent-free polyurethane fully water-based PU leather; The intrinsic flame-retardant solvent-free polyurethane for water-based PU leather for automobile interior decoration can be used without foaming or after foaming.

[0032] It should be noted that the small molecule polyol in the polyester polyol A is a combination of a difunctional small molecule polyol and a trifunctional or higher small molecule polyol, wherein the mass of the trifunctional or higher small molecule polyol accounts for 0.5-1.0% of the total mass of the polyester polyol A.

[0033] The intrinsic flame-retardant solvent-free polyurethane for all-water PU leather of the present invention is composed of an isocyanate component, a hydroxyl component and a catalyst component. The isocyanate component and the catalyst component cooperate with a specific amine chain extender, a flame-retardant polyol and a coupling agent in the hydroxyl component to achieve substantially the same level of peel strength, hydrolysis resistance and low temperature performance as an intrinsic flame-retardant solvent-free polyurethane AB material of a polycarbonate system, better flame-retardant performance, and better adhesion to a waterborne polyurethane surface layer. The intrinsic flame-retardant solvent-free polyurethane AB material has a lower cost than that of a polycarbonate system.

[0034] Example 1 Preparation of isocyanate-based components 400 kg of diphenylmethane diisocyanate was added to the reactor, stirring was started, the temperature of the reactor was controlled at 52°C, 0.04 kg of phosphoric acid was added to the reactor, and stirring was performed for 15 min; 180 kg of polyether polyol PPG-2000, 340 kg of polyether polyol PTMEG-2000, and 30 kg of dibromoneopentyl glycol were added to the reactor in batches, and finally 8 kg of liquefied diphenylmethane diisocyanate was added, the temperature of the reactor was controlled at 72°C, and after reacting for 3 hours, NCO was tested to be 10.6%, and the temperature was lowered to 45°C and discharged to obtain the isocyanate component; Preparation of hydroxyl components 100 kg of polyether polyol PTMEG-2000, 2.0 kg of chain extender ethylene glycol, 2 kg of dibromoneopentyl glycol, 0.4 kg of 3,3'-dichloro-4,4'-diaminodiphenylmethane and 0.2 kg of KH-560 were vacuum dried at 105°C for 2 hours to make the water content less than 0.05%, stirred evenly and cooled to 40-50°C to obtain a hydroxyl component; Preparation of catalyst components 1 kg of organic bismuth and 25 kg of amine catalyst DABCO EG are stirred and mixed evenly in a small reactor, and then packaged to form a catalyst component.

[0035] When used for fully water-based PU leather, the hydroxyl component, isocyanate component and catalyst component are mixed in a mass ratio of 100:60:0.5.

[0036] Example 2 Preparation of isocyanate-based components 370 kg of diphenylmethane diisocyanate was added to the reactor, stirring was started, the temperature of the reactor was controlled at 55°C, 0.04 kg of phosphoric acid was added to the reactor, and stirring was performed for 15 min; 5500 kg of PTMEG-2000, 10 kg of amine chain extender 3,3'-dichloro-4,4'-diaminodiphenylmethane, and 10 kg of dibromoneopentyl glycol were added to the reactor in batches, and finally 70 kg of liquefied diphenylmethane diisocyanate was added. The temperature of the reactor was controlled at 75°C. After reacting for 3 hours, the NCO was tested to be 11.1%, and the temperature was lowered to 43°C to discharge the material to obtain the isocyanate component.

[0037] Preparation of hydroxyl components 100kg PPG-2000, 5.0kg chain extender butanediol, 1kg dibromoneopentyl glycol, 0.4kg KH-550 and 0.2kg KH-560 were vacuum dried at 110°C for 2h to make the water content lower than 0.05%, stirred evenly and cooled to 42°C to obtain the hydroxyl component; Preparation of catalyst components 1 kg of organic bismuth and 22 kg of amine catalyst DMDEE are stirred and mixed evenly in a small reactor, and then packaged to form a catalyst component.

[0038] When used for fully water-based PU leather, the hydroxyl component, isocyanate component and catalyst component are mixed at a ratio of 100:100:0.4.

[0039] Example 3 Preparation of isocyanate-based components 330 kg of isophorone diisocyanate was added to the reactor, stirring was started, the temperature of the reactor was controlled at 56 ° C, 0.04 g of phosphoric acid was added to the reactor, and stirring was performed for 15 min; 190 kg of polyether polyol PPG-1000, 330 kg of polyether polyol PTMEG-2000, and 50 kg of polyether polyol were added to the reactor in batches, and the temperature of the reactor was controlled at 74 ° C. After reacting for 3 hours, the NCO was tested to be 14.8%, and the temperature was reduced to 41 ° C and the material was discharged to obtain the isocyanate component.

[0040] Preparation of hydroxyl components 100kg of amine chain extender B3, 9kg of propylene glycol, 5kg of polyether polyol, 0.4kg of DC3042 and 0.2kg of DC3043 were dried under vacuum at 112°C for 2h to reduce the water content to less than 0.05%, stirred evenly and cooled to 45°C to obtain the hydroxyl component.

[0041] Preparation of catalyst components 1 kg of organic bismuth and 28 kg of amine catalyst DMEA are stirred and mixed evenly in a small reactor, and then packaged to form a catalyst component.

[0042] When used for fully water-based PU leather, the hydroxyl component, isocyanate component and catalyst component are mixed at a ratio of 100:100:0.7.

[0043] Comparative Example 1 uses Covestro solvent-based polyurethane resin Desmocoll® 530 / 1 produced by Dongguan Bailing New Materials Co., Ltd. purchased on the market; Comparative Example 2 uses TPU model 1154D50 intrinsic flame retardant solvent-free polyurethane purchased on the market.

[0044] Embodiment 1-3 and comparative example 1-2 are coated on release paper coated with a water-based polyurethane surface layer (coating amount is 20 silks), and then dried and matured in an oven at 100-130°C for 5-10 minutes, and the semi-dry resin is bonded to the base cloth (all-water-based fixed island PU leather). After aging, the release paper is peeled off to obtain solvent-free polyurethane all-water-based PU leather.

[0045] The prepared all-water-based PU leather was tested for peel strength and hydrolysis resistance, a low-temperature folding test was performed in a low-temperature box, and a temperature resistance test was performed in a high-temperature oven. The test results are shown in Table 1 below.

[0046] Table 1 Test results of fully water-based PU leather prepared using polyurethanes of Examples 1 to 3 and Comparative Example

[0047] As shown in Table 1, the present invention adopts solvent-free polyurethane resin, avoids environmental pollution and safety hazards caused by solvent-based polyurethane, and has excellent bonding strength, hydrolysis resistance and flame retardancy, and its performance index is comparable to that of the intrinsic flame retardant solvent-free polyurethane AB material of the polycarbonate system. In addition, the production cost of the present invention is lower, providing a more cost-effective solution for automotive interior manufacturers.

[0048] The above are only embodiments of the present invention. The common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for technicians in this field, without departing from the structure of the present invention, they can also make several deformations and improvements, which should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. An intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather, characterized in that: It comprises a hydroxyl component, an isocyanate component and a catalyst component, wherein the mass ratio of the hydroxyl component, the isocyanate component and the catalyst component is 100:40-120:0.3-1.0; Wherein, the hydroxyl component includes an amine chain extender, a flame retardant polyol, and an auxiliary agent.

2. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 1, characterized in that: The hydroxyl component comprises the following materials in proportion by weight: 90-110 parts of polyether polyol, 1.5-10 parts of chain extender, 10-30 parts of flame retardant polyol, and 2-10 parts of auxiliary agent.

3. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 1, characterized in that: The isocyanate-based component comprises the following materials in proportion by weight: 450-600 parts of polyether polyol, 1-10 parts of amine chain extender, 10-30 parts of flame retardant polyol, 0.01-0.05 parts of polymerization inhibitor, and 300-500 parts of isocyanate.

4. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 3, characterized in that: The amine chain extender is a mixture of one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, liquid 3,3'-dichloro-4,4'-diaminodiphenylmethane modified with formaldehyde, ethylenediamine, and N,N-dihydroxy (diisopropyl) aniline.

5. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to any one of claims 2 to 4, characterized in that: The polyether polyol is a mixture of one or more of polyethylene oxide polyol, polypropylene oxide polyol and polytetramethylene glycol polyol; Wherein, the number average molecular weight of the polyether polyol is 800-4000.

6. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 1, characterized in that: The catalyst includes an organic metal catalyst and an amine catalyst; Wherein, the mass ratio of the organic metal catalyst to the amine catalyst is 1:20-30; The organic metal catalyst is a mixture of one or more of organic bismuth and dibutyltin dilaurate; The amine catalyst is a mixture of one or more of triethylenediamine, tetramethyldiethylenetriamine, and 2,2-dimorpholinyldiethyl ether.

7. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 3, characterized in that: The isocyanate is a mixture of one or more of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, p-phenylenediisocyanate and tetramethyldimethylene diisocyanate.

8. The intrinsic flame retardant solvent-free polyurethane for automotive interior water-based PU leather according to claim 5, characterized in that: The auxiliary agent is a mixture of one or both of a silane coupling agent and an epoxy resin; The chain extender is a mixture of one or more of ethylene glycol, propylene glycol and 1,4-butanediol; The polymerization inhibitor is an acidic substance capable of providing active hydrogen, including but not limited to a mixture of one or more of phosphoric acid, hypophosphorous acid, hydroquinone, erucic acid, benzoic acid, and citric acid.

9. A method for preparing an intrinsic flame-retardant solvent-free polyurethane for water-based PU leather for automobile interior, characterized in that: The following steps are involved: Preparation of isocyanate-based component: isocyanate and polymerization inhibitor are stirred in a reaction kettle at 45-55° C. for 5-30 minutes, and then polyether polyol and flame retardant polyol are added, and reacted at 70-75° C. for 2-4 hours to obtain the isocyanate-based component; Preparation of hydroxyl component: drying the polyether polyol at 100-120° C. under vacuum conditions for 1-2 hours to obtain a polyether polyol having a moisture content of less than 0.05%; The flame retardant polyol, chain extender and auxiliary agent are added and mixed uniformly to obtain a hydroxyl component.

10. Use of an intrinsic flame retardant solvent-free polyurethane for water-based PU leather for automobile interior, characterized in that: The intrinsic flame-retardant solvent-free polyurethane for automotive interior water-based PU leather is used for the middle layer of the fully water-based PU leather. The hydroxyl component, the isocyanate component and the catalyst component are mixed in a mass ratio of 100:40-120:0.3-1.0, and coated on a release paper coated with a water-based polyurethane surface layer in a coating amount of 18 to 22 strands, and then dried and matured in an oven at 100-130° C., and the semi-dried resin is bonded to the base cloth. After aging, the release paper is peeled off to obtain the solvent-free polyurethane fully water-based PU leather; The intrinsic flame-retardant solvent-free polyurethane for water-based PU leather for automobile interior decoration can be used without foaming or after foaming.

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