Waterborne polyurethane fireproof coating and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane, and discloses a water-based polyurethane fireproof coating and a preparation method thereof, pentaerythritol diphosphate diphosphoryl chloride, 4-methoxy-L-phenylalanine, pyridine hydrochloride and the like are used as reactants to prepare a novel carboxyl-containing water-based flame-retardant chain extender, and the water-based flame-retardant chain extender is used as a fire retardant. And carrying out polymerization reaction with dihydric alcohol and diisocyanate monomer to obtain the waterborne polyurethane fireproof coating. The polyurethane water-based emulsion is good in dispersity, high in emulsion stability and excellent in hardness; meanwhile, a nitrogen-phosphorus flame-retardant structure of the bis-spirophosphamide is grafted into a polyurethane molecular chain, so that the combustion limit oxygen index of the polyurethane film material is remarkably improved and reaches 27.9-29.6%, and the UL-94 grade reaches V-0.

Description

TECHNICAL FIELD

[0001] The application relates to the polyurethane technical field, in particular to a water-based polyurethane fireproof coating and a preparation method thereof. BACKGROUND

[0002] Water-based coatings do not have volatile organic solvents, are green and environmentally friendly, and have excellent film-forming properties, and are widely applied in aspects such as interior and exterior wall coatings, metal coatings, automobile coatings and the like. The polyurethane water-based coating has excellent mechanical properties and good elasticity, and is very widely applied. However, the polyurethane water-based coating film has the defects of high water absorption, poor water resistance and flammability, which limit the practical application of the polyurethane water-based coating in water-resistant fireproof coatings.

[0003] It is of great significance to develop water-resistant water-based polyurethane fireproof coatings. Patent CN111574676B discloses that a flame-retardant chain extender is synthesized by using hexachlorocyclotriphosphazene and 2,2-biphenyldiol, hexanediamine, and the flame retardant is connected to the polyurethane molecular main chain through a chemical bond, thereby enhancing the thermal stability and flame retardance of the water-based polyurethane film. However, the patent additionally adds anionic water-based chain extenders such as dimethylol propanoic acid and dimethylol butanoic acid. The application prepares a new type of water-based flame-retardant chain extender, aiming to improve the water resistance, flame-retardant fireproof performance and the like of the water-based polyurethane coating. SUMMARY

[0004] The technical problem solved by the application is to provide a water-based polyurethane fireproof coating with good water resistance.

[0005] Technical scheme: A water-based polyurethane fireproof coating, comprising 100 parts by weight of dihydric alcohol, 42-68 parts of diisocyanate monomer, 4-5 parts of small-molecule chain extender, 18-26 parts of water-based flame-retardant chain extender, 0.12-0.16 parts of dibutyltin dilaurate, 0.8-1.5 parts of dispersant, 0.5-1 part of defoaming agent, 0.4-0.8 parts of leveling agent and 4-15 parts of filler. The structural formula of the water-based flame-retardant chain extender is as follows: .

[0006] The filler comprises montmorillonite, talcum powder and vermiculite powder.

[0007] Further, the dihydric alcohol comprises polyethylene glycol, polypropylene glycol, polycarbonate dihydric alcohol and polytetrahydrofuran ether dihydric alcohol; the diisocyanate monomer comprises toluene-2,4-diisocyanate, 4,4-diphenylmethane diisocyanate and isophorone diisocyanate; and the small-molecule chain extender comprises 1,4-butanediol.

[0008] Further, the preparation method of the water-based flame-retardant chain extender is as follows: Step (1), the reactor is placed in an ice water bath, and a reaction solvent, 100 parts by weight of pentaerythritol bisphosphate dichlorophosphoryl chloride, 135-160 parts of 4-methoxy-L-phenylalanine, and 80-110 parts of N,N-diisopropylethylamine are added, stirring is performed, the ice water bath is removed, and after reaction, rotary evaporation, dichloromethane recrystallization are performed to obtain a flame retardant intermediate.

[0009] Step (2), 100 parts of pyridine hydrochloride are added to a reactor containing a condensation reflux device, heated to a molten state, 7-10 parts of the flame retardant intermediate are added, after reaction, saturated sodium bicarbonate solution and dichloromethane are added, extraction is performed, the organic phase is dried and removed, rotary evaporation, dichloromethane recrystallization are performed to obtain the water-based flame-retardant chain extender.

[0010] Further, the reaction solvent in step (1) includes toluene, dichloromethane, and tetrahydrofuran.

[0011] Further, the reaction in step (1) is performed at a temperature of 25-40°C for 5-10h.

[0012] Further, the reaction in step (2) is performed at a temperature of 200-210°C for 2-4h.

[0013] Further, the preparation method of the water-based polyurethane fireproof coating is characterized in that: a dihydric alcohol is added to a reactor, vacuum drying is performed to remove water, nitrogen is introduced, a diisocyanate monomer is added, reaction is performed at a temperature of 70-80°C for 2-3h, a water-based flame-retardant chain extender and dibutyltin dilaurate are added, reaction is performed for 30-60min, triethylamine is added for neutralization, water is added, a small molecule chain extender is added, and reaction is continuously performed for 20-40min, finally, a dispersing agent, a defoaming agent, a leveling agent, and a filler are added, stirring and dispersion are performed to obtain the water-based polyurethane fireproof coating.

[0014] Beneficial technical effects: the present application uses pentaerythritol bisphosphate dichlorophosphoryl chloride, 4-methoxy-L-phenylalanine, pyridine hydrochloride, etc. as reactants to prepare a novel water-based flame-retardant chain extender containing a carboxyl group, which is subjected to a polymerization reaction with a dihydric alcohol and a diisocyanate monomer to obtain a water-based polyurethane fireproof coating.

[0015] The polyurethane water-based emulsion has good dispersibility, high emulsion stability, and excellent hardness; meanwhile, the nitrogen-phosphorus flame-retardant structure of the bispirocyclic phosphoramide is grafted into the polyurethane molecular chain, which significantly improves the limiting oxygen index of the polyurethane film material combustion to 27.9-29.6%, and the UL-94 level reaches V-0. DETAILED DESCRIPTION

[0016] Main raw materials of the present application: Pentaerythritol bisphosphate dichlorophosphoryl chloride, CAS No. 714-87-4, structural formula is .

[0017] 4-methoxy-L-phenylalanine: CAS No. 6230-11-1.

[0018] Dispersant: Model HY-6350.

[0019] Defoaming agent: Model XPJ55.

[0020] Leveling agent: Brand EFKA3777.

[0021] Example 1 Put the reactor in an ice water bath, add tetrahydrofuran solvent, 100 parts by weight of pentaerythritol bisphosphate dichlorophosphoryl chloride, 160 parts of 4-methoxy-L-phenylalanine, 110 parts of N,N-diisopropylethylamine, after stirring, remove the ice water bath, react at a temperature of 30°C for 8h, rotary evaporation, dichloromethane recrystallization, to obtain a flame retardant intermediate.

[0022] Add 100 parts of pyridine hydrochloride to the reactor containing a condensation reflux device, heat to a molten state, add 10 parts of flame retardant intermediate, react at a temperature of 200°C for 2h, cool, add saturated sodium bicarbonate solution, dichloromethane, extract, dry the organic phase, rotary evaporation, dichloromethane recrystallization, to obtain a water-based flame retardant chain extender.

[0023] Add 100 parts by weight of polyethylene glycol to the reactor, vacuum dry to remove water, introduce nitrogen, add 42 parts of toluene-2,4-diisocyanate, react at a temperature of 70°C for 3h, then add 18 parts of water-based flame retardant chain extender, 0.13 parts of dibutyltin dilaurate, react for 60 min, add triethylamine for neutralization, add water, 4 parts of small molecule chain extender 1,4-butanediol, continue to react for 20 min, finally add 0.8 parts of dispersant, 1 part of defoaming agent, 0.5 parts of leveling agent, 4 parts of filler vermiculite powder, stir and disperse, control the total solid content of the emulsion to be 40%, to obtain a water-based polyurethane fireproof coating.

[0024] Example 2 Put the reactor in an ice water bath, add toluene solvent, 100 parts by weight of pentaerythritol bisphosphate dichlorophosphoryl chloride, 135 parts of 4-methoxy-L-phenylalanine, 110 parts of N,N-diisopropylethylamine, after stirring, remove the ice water bath, react at a temperature of 40°C for 5h, rotary evaporation, dichloromethane recrystallization, to obtain a flame retardant intermediate.

[0025] 100 parts of pyridine hydrochloride was added to the reactor containing condensation reflux device, heated to a molten state, 8 parts of flame retardant intermediate was added, reacted at a temperature of 210℃ for 3h, cooled, saturated sodium bicarbonate solution, dichloromethane was added, extraction was carried out, the organic phase was dried and removed, rotary evaporation, dichloromethane recrystallization, water-based flame retardant chain extender was obtained.

[0026] 100 parts by weight of polypropylene glycol was added to the reactor, vacuum drying to remove water, nitrogen was introduced, 68 parts of 4,4-diphenyl methane diisocyanate was added, reacted at a temperature of 75℃ for 2h, 22 parts of water-based flame retardant chain extender, 0.16 parts of dibutyltin dilaurate was added, reacted for 30min, triethylamine was added for neutralization, water was added, 4 parts of small molecule chain extender 1,4-butanediol was added, and the reaction was continued for 20min, finally 1 part of dispersant, 1 part of defoaming agent, 0.4 parts of leveling agent, 4 parts of filler vermiculite powder was added, stirring and dispersing, the total solid content of the emulsion was controlled at 40%, water-based polyurethane fireproof coating was obtained.

[0027] Example 3 The reactor was placed in an ice water bath, tetrahydrofuran solvent, 100 parts by weight of pentaerythritol bisphosphate dichloride, 135 parts of 4-methoxy-L-phenylalanine, 102 parts of N,N-diisopropyl ethylamine was added, after stirring, the ice water bath was removed, and the reaction was carried out at a temperature of 30℃ for 5h, rotary evaporation, dichloromethane recrystallization, flame retardant intermediate was obtained.

[0028] 100 parts of pyridine hydrochloride was added to the reactor containing condensation reflux device, heated to a molten state, 8 parts of flame retardant intermediate was added, reacted at a temperature of 210℃ for 2h, cooled, saturated sodium bicarbonate solution, dichloromethane was added, extraction was carried out, the organic phase was dried and removed, rotary evaporation, dichloromethane recrystallization, water-based flame retardant chain extender was obtained.

[0029] 100 parts by weight of polytetrahydrofuran ether diol was added to the reactor, vacuum drying to remove water, nitrogen was introduced, 64 parts of isophorone diisocyanate was added, reacted at a temperature of 70℃ for 3h, 22 parts of water-based flame retardant chain extender, 0.16 parts of dibutyltin dilaurate was added, reacted for 60min, triethylamine was added for neutralization, water was added, 5 parts of small molecule chain extender 1,4-butanediol was added, and the reaction was continued for 40min, finally 1 part of dispersant, 0.5 parts of defoaming agent, 0.6 parts of leveling agent, 15 parts of filler talc powder was added, stirring and dispersing, the total solid content of the emulsion was controlled at 40%, water-based polyurethane fireproof coating was obtained.

[0030] Example 4 Put the reactor in the ice water bath, add dichloromethane, 100 parts by weight of pentaerythritol bisphosphate dichlorophosphoryl chloride, 148 parts of 4-methoxy-L-phenylalanine, 102 parts of N,N-diisopropylethylamine, stir after removing the ice water bath, react at a temperature of 30℃ for 8h, rotary evaporation, dichloromethane recrystallization, to obtain a flame retardant intermediate.

[0031] Put 100 parts of pyridine hydrochloride into the reactor containing a condensation reflux device, heat to a molten state, add 7 parts of the flame retardant intermediate, react at a temperature of 210℃ for 2h, cool, add saturated sodium bicarbonate solution, dichloromethane, extract, dry the organic phase, rotary evaporation, dichloromethane recrystallization, to obtain an aqueous flame retardant chain extender.

[0032] Put 100 parts by weight of polycarbonate diol into the reactor, vacuum dry to remove water, introduce nitrogen, add 42 parts of toluene-2,4-diisocyanate, react at a temperature of 75℃ for 2h, then add 26 parts of the aqueous flame retardant chain extender, 0.16 parts of dibutyltin dilaurate, react for 60min, add triethylamine for neutralization, add water, 5 parts of small molecule chain extender 1,4-butanediol, continue to react for 20min, finally add 1 part of dispersant, 0.8 parts of defoaming agent, 0.8 parts of leveling agent, 10 parts of filler montmorillonite, stir and disperse, control the total solid content of the emulsion to be 40%, to obtain an aqueous polyurethane fireproof coating.

[0033] Comparative Example 1 Put 100 parts by weight of polyethylene glycol into the reactor, vacuum dry to remove water, introduce nitrogen, add 42 parts of toluene-2,4-diisocyanate, react at a temperature of 70℃ for 3h, then add 0.13 parts of dibutyltin dilaurate, 4 parts of small molecule chain extender 1,4-butanediol, continue to react for 20min, finally add water, 0.8 parts of dispersant, 1 part of defoaming agent, 0.5 parts of leveling agent, 4 parts of filler vermiculite powder, stir and disperse, to obtain a polyurethane coating.

[0034] Stability test of polyurethane coating: the obtained aqueous polyurethane fireproof coating was left still at 25℃ for 7-30 days, and the stability of the aqueous emulsion was observed.

[0035] Table 1 Stability of polyurethane aqueous emulsion

[0036] Pour the aqueous polyurethane fireproof coating on a clean glass plate, dry at 60℃ for 12h, to obtain a polyurethane film; test the water resistance of the paint film according to the method of GB / T 1733-1993; test the pencil hardness according to the method of GB / T 6739-2006.

[0037]

[0038] The water-based flame-retardant chain extender containing carboxyl in Examples 1-4 As the water-based flame-retardant chain extender, the polyurethane water-based emulsion has good dispersibility, high emulsion stability and excellent hardness.

[0039] The flame-retardant performance of the polyurethane film material is tested according to GB / T 2406.1-2008 and UL-94 fire rating method.

[0040]

[0041] In Examples 1-4, the water-based flame-retardant chain extender is used to graft the nitrogen-phosphorus flame-retardant structure of double spiro phosphoramidate into the polyurethane molecular chain, which significantly improves the limiting oxygen index of the polyurethane film material combustion to 27.9-29.6%, and the UL-94 rating reaches V-0.

[0042] The above is a further detailed description of the present application in combination with specific preferred embodiments, which cannot be considered as limiting the specific embodiments of the present application to only this. For ordinary skilled persons in the technical field to which the present application belongs, some simple deductions or substitutions can be made without departing from the concept of the present application, which should be considered as belonging to the scope of patent protection determined by the submitted claims.

Claims

1. A water-based polyurethane fire-retardant coating, characterized in that: It includes 100 parts by weight of diol, 42-68 parts of diisocyanate monomer, 4-5 parts of small molecule chain extender, 18-26 parts of water-based flame retardant chain extender, 0.12-0.16 parts of dibutyltin dilaurate, 0.8-1.5 parts of dispersant, 0.5-1 part of defoamer, 0.4-0.8 parts of leveling agent, and 4-15 parts of filler; The structural formula of the water-based flame retardant chain extender is: ; The filler includes montmorillonite, talc, and vermiculite.

2. The water-based polyurethane fire-retardant coating according to claim 1, characterized in that: The diols include polyethylene glycol, polypropylene glycol, polycarbonate diol, and polytetrahydrofuran ether diol; the diisocyanate monomers include toluene-2,4-diisocyanate, 4,4-diphenylmethane diisocyanate, and isophorone diisocyanate; and the small molecule chain extender includes 1,4-butanediol.

3. The water-based polyurethane fire-retardant coating according to claim 1, characterized in that: The preparation method of the water-based flame retardant chain extender is as follows: Step (1): Place the reactor in an ice-water bath, add the reaction solvent, 100 parts by weight of pentaerythritol diphosphophosphate diphosphoryl chloride, 135-160 parts of 4-methoxy-L-phenylalanine, and 80-110 parts of N,N-diisopropylethylamine. After stirring, remove the ice-water bath, and after the reaction, rotary evaporate the mixture. Recrystallize the dichloromethane to obtain the flame retardant intermediate. Step (2): Add 100 parts of pyridine hydrochloride to a reactor containing a reflux condenser, heat to a molten state, add 7-10 parts of flame retardant intermediate, cool after reaction, add saturated sodium bicarbonate solution and dichloromethane, extract, dry the organic phase to remove it, rotary evaporate, recrystallize the dichloromethane to obtain the water-based flame retardant chain extender.

4. The water-based polyurethane fire-retardant coating according to claim 3, characterized in that: The reaction solvents in step (1) include toluene, dichloromethane, and tetrahydrofuran.

5. The waterborne polyurethane fire-retardant coating according to claim 3, characterized in that: The reaction in step (1) is carried out at a temperature of 25-40℃ for 5-10 hours.

6. The waterborne polyurethane fire-retardant coating according to claim 3, characterized in that: The reaction in step (2) is carried out at a temperature of 200-210℃ for 2-4 hours.

7. A method for preparing a waterborne polyurethane fire-retardant coating as described in any one of claims 1-6, characterized in that: Diol is added to a reactor, vacuum dried to remove water, nitrogen is introduced, diisocyanate monomer is added, and the reaction is carried out at 70-80℃ for 2-3 hours. Then, water-based flame retardant chain extender and dibutyltin dilaurate are added, and the reaction is carried out for 30-60 minutes. Triethylamine is added for neutralization, water and small molecule chain extender are added, and the reaction is continued for 20-40 minutes. Finally, dispersant, defoamer, leveling agent and filler are added, and the mixture is stirred and dispersed to obtain water-based polyurethane fireproof coating.

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