Preparation method of key material for fire-retardant, light-resistant, low-voc, easily permeable waterborne polyurethane coating

Abstract

The present application relates to the preparation method of fire-retardant, light-resistant, low VOC, easily permeable water-based polyurethane coating, polytetrahydrofuran ether diol, polyol are added in the reaction container, after mixing, stirring and drying 1~2h to remove water, cooling, adding isophorone diisocyanate, dibutyltin dilaurate, stirring under the condition of 85~95℃ for 1~2h, polyurethane prepolymer is obtained; hyperbranched flame retardant is added to the polyurethane prepolymer for primary chain extension, stirring reaction, the system is cooled, dimethylol propionic acid is added for secondary chain extension reaction, cooling, adding alkyl glycoside, adding char former, stirring for 1h, adding triethylamine, adding acetone, stirring to reduce viscosity, after reducing to 25~30℃, adding water, adjusting the speed of stirrer to 2000r / min, adjusting pH to 7, adding saturated sodium bisulfite and ethyl carbamate, reacting at room temperature, filtering and precipitating, adjusting pH to 7~8, the fire-retardant, light-resistant, low VOC, easily permeable water-based polyurethane coating is obtained, the obtained polyurethane has the advantages of fire-retardancy, low VOC and light resistance.

Description

[0001] The present application is a divisional application of 2023111285422. TECHNICAL FIELD

[0002] The present application relates to the preparation method of polyurethane coatings, in particular to the preparation method of flame-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coatings. BACKGROUND

[0003] Waterborne polyurethane (WPU) has a high sales proportion of 52% in waterborne coatings due to its advantages of weather resistance, non-pollution, safety and reliability, low cost, and easy use. However, WPU is flammable without flame-retardant treatment, and it is necessary to perform flame-retardant treatment on WPU.

[0004] Mengjie Cui et al. designed and synthesized a halogen-free flame-retardant waterborne polyurethane based on the synergistic effect of phosphorus and silicon. A novel flame retardant with dihydroxy groups was prepared using p-hydroxybenzaldehyde, 3-aminopropanol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials. Then, it was added to the synthesis of waterborne polyurethane, and a flame-retardant waterborne polyurethane (FR / Si-WPU) with phosphorus (P) and silicon (Si) units was successfully prepared. Its oxygen index value increased from 18.2% to 28.6%, and the peak smoke production rate was reduced by 70.5% compared with pure waterborne polyurethane. There is still a lot of room for improvement in the mechanical properties and flame-retardant properties of waterborne polyurethane.

[0005] Chen et al. synthesized a hyperbranched flame retardant containing P / Si, which was applied to polyurethane to significantly improve its flame-retardant properties. It is a kind of hyperbranched nitrogen phosphorus silicon (HBNPSi) flame retardant, which is synthesized by addition reaction of NCO functional group of 3-isocyanate propyl triethoxysilane (IPTS) and OH functional group of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaanthracene-10-oxide (DOPO-BQ). After the reaction is completed, isocyanuric acid triglycidyl ester (TGIC) is introduced to carry out ring-opening reaction. Subsequently, a sol-gel method is used to start the hydrolysis-condensation reaction on TGIC-IPTS-DOPO-BQ to form a hyperbranched nitrogen phosphorus silicon (HBNPSi) flame retardant. The addition of this flame retardant to polyurethane increases the carbon residue from 0.8% to 8.1% and the LOI value from 19% to 26%. There is still a lot of room for improvement in the flame-retardant properties, such as the risk of secondary combustion caused by molten droplets produced during combustion.

[0006] Since the 1960s, solvent-based polyurethane has been commonly used, and a large amount of organic solvent is needed in the production process. Organic solvents have the disadvantages of strong odor, easy explosion, serious pollution, harm to human health, etc. In addition, people's environmental awareness is increasing, and the emission of volatile organic compounds (VOCs) is limited. In order to reduce the emission of volatile organic compounds (VOCs), China has introduced a series of policies to encourage the use of water-based coating products and restrict the production of traditional solvent-based coatings. In March 2020, the State issued the "Low Volatile Organic Compound Content Coating Product Technical Requirements", which precisely defines the volatile organic compound (VOC) content requirements in water-based coatings and solvent-based coatings. In the future, with the tightening of environmental protection policies, the demand for water-based product substitution will be more significant. Water-based polyurethane has been widely concerned due to its environmental protection and pollution-free advantages.

[0007] The invention achievement CN202011624359.8 of the team adopts the reaction of imine of polyethylene imine and acyl chloride of 2-acetoxy isobutyryl chloride, and then adds amino urea to react with the remaining acyl chloride. The obtained compound reacts with the hydroxyl and carboxyl groups of polyurethane during the film forming process of polyurethane, accelerating the release of VOC. At the same time, the amino group can also react with the carbonyl group of acetone, especially in the heating environment of film forming (such as the need for drying in the oven in leather coating finishing), which can improve the VOC release of polyurethane, and the VOC of polyurethane mainly comes from acetone. The advantages of the invention of polyethylene imine, 2-acetoxy isobutyryl chloride and amino urea lie in the ability to quickly remove VOC. This method is still relatively complex to operate, and the effect still has room for improvement.

[0008] There is no research opportunity for polyurethane permeability on the market at present, and permeability is also an important indicator of polyurethane, so it is necessary to conduct research.

[0009] As the research progress of the prior art, it is necessary to further optimize the indicators in the reaction of fire retardant and VOC, improve the fire retardant grade and permeability and other fire retardant indicators, reduce the VOC release amount, and further improve the market share of water-based polyurethane. SUMMARY

[0010] The application mainly solves the technical problems of the Shandong Province small and medium-sized enterprise promotion project "Research and industrialization of flame-retardant, light-resistant, low-VOC polyurethane coating 2022TSGC1354", the design idea of the application is that the hyperbranched flame retardant is used as a chain extender of a polyurethane synthesis prepolymer, meanwhile, butyl glycoside (alkyl glycoside) is used as a chain extender, a permeable anionic emulsifier is combined into a chain segment of the polyurethane, saturated sodium bisulfite and ethyl carbamate are used to treat acetone solvent in the polyurethane, and acetone is a main source of VOC of the polyurethane, in addition, the application also uses cortex acacia bark tannin to react with phosphorus trichloride, because cortex acacia bark has a large number of phenolic hydroxyl groups, the cortex acacia bark reacts with P-Cl, the obtained cortex acacia bark is more easily carbonized in the phosphorus compound, and the carbonization amount is increased, ethanolamine is introduced, the content of hydroxyl groups in the system is increased, the carbon content of the carbonization agent is increased, and the flame retardance of the system is improved.

[0011] The preparation method of the flame-retardant, light-resistant, low-VOC and easily permeable water-based polyurethane coating is characterized by comprising the following steps:

[0012] (a) 16-18 parts of polytetrahydrofuran ether diol and 16-18 parts of polyol are added into a reaction container, the mixture is stirred and dried at 120-130 DEG C for 1-2 h to remove water, the temperature is reduced to 85-95 DEG C, 15-20 parts of isophorone diisocyanate (IPDI) and 0.2-0.5 parts of dibutyltin dilaurate are added, and the stirring reaction is carried out at 85-95 DEG C for 1-2 h to obtain a polyurethane prepolymer;

[0013] (b) 3-4 parts of hyperbranched flame retardant are added into the polyurethane prepolymer for primary chain extension, the stirring reaction is carried out for 1-2 h, the system is cooled to 58-68 DEG C, 1-2 parts of dimethylol propionic acid (DMPA) are further added for secondary chain extension, the reaction is carried out for 0.5-1.5 h, the temperature is reduced to 40-50 DEG C, 1-3 parts of alkyl glycoside are added, the reaction is carried out for 0.5-1.5 h, 0.2-0.5 parts of coumarin derivative are further added, the reaction is carried out at 60-90 DEG C for 1-2 h, 0.2-0.5 parts of carbonization agent are further added, the stirring reaction is carried out at 50-60 DEG C for 1 h, 2-4 parts of triethylamine are further added, the reaction is carried out for 0.5-1.5 h, 2-3 parts of acetone are further added, the viscosity is reduced by stirring, the temperature is reduced to 25-30 DEG C, 115-125 parts of water are added, the stirring speed is adjusted to 2000 r / min, the reaction is carried out for 0.5-0.6 h, the pH is adjusted to 7, 14-16 parts of saturated sodium bisulfite (40%) and 1-2 parts of ethyl carbamate are added for room temperature reaction, the filter precipitate is separated, the upper layer is taken as a polyurethane emulsion, the pH is adjusted to 7-8, and the flame-retardant, low-VOC and easily permeable water-based polyurethane coating is obtained.

[0014] The polyol is any one of polypropylene glycol and polyethylene glycol, and the molecular weight of the polypropylene glycol and the polyethylene glycol is 2000 g / mol.

[0015] The molecular weight of the polytetrahydrofuran ether diols is 2000 g / mol.

[0016] A method for preparing a fire-retardant, low VOC, water-permeable polyurethane coating, the preparation method of the hyperbranched fire retardant being as follows:

[0017] (a) Preparation of the intermediate: 300-306 parts of tetrahydrofuran are taken in a reaction vessel and heated at 50-60°C, 63-69 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 27-33 parts of maleic anhydride (MA) are added to the reaction vessel, and the mixture is stirred at 50-60°C for 6-7 h under reflux condensation to obtain a light yellow liquid, which is the intermediate solution. The intermediate solution is dried at 30-40°C for 9-10 h to obtain the intermediate product.

[0018] (b) Preparation of the branched fire retardant: 31-33 parts of the intermediate of step (a), 13-15 parts of diisopropanolamine (DIPA) and 0.3-0.5 parts of p-toluenesulfonic acid are dissolved in 10-15 parts of N,N-dimethylformamide, and the mixture is stirred at 120-130°C for 6-7 h in a reaction vessel to obtain a black-red liquid. The liquid is transferred to a beaker and dried under vacuum at 85-95°C for 8-9 h to constant weight to obtain the hyperbranched fire retardant.

[0019] The preparation method of the butyl glycoside (alkyl glycoside) is as follows: 2-2.5 parts of n-butanol and 0.5 parts of an acidic catalyst are added to a 250 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, and the mixture is stirred and slowly heated to 100-120°C. Then 1 part of glucose is added to the flask and reacted under reflux constant temperature for 30-70 min. The reaction end point is identified, and after the reaction end point is determined, the reaction mixture is quickly cooled to about 70-80°C. Sodium bicarbonate is added to adjust the pH value to 7-8. The mixture is stirred for 15-30 min to make it weakly alkaline. The butanol is removed under reduced pressure, the temperature is controlled at about 50°C, and the vacuum degree is 1.33 KPa. The butanol removal end point is determined by the fact that one drop of butanol flows out every 1 min or longer. Then 0.5-0.8 parts of maleic anhydride is added to the system, and the mixture is reacted at 60-90°C for 1-2 h. Then 0.5-0.8 parts of citric acid is added, and the mixture is reacted at 80-90°C for 1-2 h to obtain the butyl glycoside (alkyl glycoside).

[0020] The acidic catalyst is any one of dodecylbenzenesulfonic acid, citric acid and anhydrous aluminum chloride.

[0021] The preparation method of the char-forming agent is as follows: 1 part of Chinese olive bark extract is added with 2-3 parts of phosphorus trichloride, and stirred and reacted at 50-60 DEG C for 1-2 hours, hydrogen chloride gas is generated in the system, and sodium hydroxide solution is used as the absorbing liquid, after the addition is completed, the system is heated to 45-50 DEG C, and stirred and reacted for 1-2 hours to remove HCl gas, when the system does not release obvious HCl gas, it is cooled to room temperature, 0.05-0.1 parts of ethanolamine is added dropwise within 1 hour, and the stirring and reaction is continued at 30-50 DEG C for 1-2 hours, a yellowish transparent viscous liquid is obtained, and the char-forming agent is obtained.

[0022] The preparation method of the coumarin derivative is as follows: 10.6 parts of resorcinol, 12-14 parts of ethyl acetoacetate and 0.20-0.4 parts of p-toluene sulfonic acid are added into a three-necked flask, and stirred at a rotating speed of 220 r / min and heated to 70-90 DEG C, with the reaction, the reactants change from colorless transparent liquid into light yellow liquid, and then into yellow viscous substance, after 2-3 hours of reaction, the heating is stopped, the three-necked flask is removed, and the mixture in the flask is transferred into a Buchner funnel for filtration, and washed with ice water, a yellow solid crude product is obtained, the crude product is recrystallized with 67% ethanol, white needle-like crystals are obtained, and the crystals are dried in a vacuum drying oven, and the coumarin derivative is obtained.

[0023] The advantages of the present application are as follows:

[0024] (1) The preparation principle of the flame retardant is that the phosphorus-hydrogen bond (P-H) in DOPO and the carbon-carbon double bond (-C=C-) in maleic anhydride undergo addition reaction to generate an intermediate, DOPO provides carbon source and acid source, maleic anhydride provides carbon source, the anhydride group in the intermediate undergoes ring-opening reaction with N-H bond and hydroxyl group in diisopropanolamine to generate the flame retardant, diisopropanolamine provides gas source, when the flame retardant is decomposed by heat, on one hand, ammonia gas and nitrogen oxide are generated to reduce the mass of the system, and the gas is wrapped on the surface to insulate air and reduce the contact area with combustion-supporting gas; on the other hand, the flame retardant is decomposed by heat to continuously generate acidic substances such as polyphosphoric acid and metaphosphoric acid to promote surface carbonization, and a dense porous carbon layer is formed on the surface to achieve the effect of flame retardation; the hyperbranched flame retardant is applied to the primary chain extension process of polyurethane, a large number of hydroxyl groups (-OH) exist on the flame retardant, which increases the possibility of grafting, the hydroxyl groups (-OH) react with isocyanate groups (-NCO) on the prepolymer to generate carbamate groups (-NHCOO-), and the flame-retardant group composition is introduced, the polyurethane is burned, on one hand, phosphorus and nitrogen elements generate phosphorus and nitrogen flame-retardant gases in the initial stage of combustion, the gases are wrapped on the surface to play a good barrier effect and inhibit the conduction of combustible gas, thereby improving the flame-retardant performance of the polyurethane, on the other hand, the flame retardant acts as a chain extender in the synthesis of polyurethane, the main chain structure of the polyurethane is changed, the heat resistance of the main chain is improved when the main chain is heated, and the carbonization property is improved, so the limiting oxygen index of the flame retardation is improved.

[0025] (2) The organic solvent in the application is mainly acetone, which is the main factor affecting VOC. The principle of generating crystals by reacting saturated sodium bisulfite with methyl ketone or aldehyde is adopted to reduce VOC in polyurethane at room temperature, and ethyl carbamate is used to improve the reaction of sodium bisulfite with carbonyl in ketone to reduce the VOC of the system.

[0026] (3) In the presence of an acidic catalyst, acetalization reaction occurs between the glucose hemiacetal hydroxyl and the n-butanol alcohol hydroxyl to generate butyl glycoside and water. The oxygen atom of the glucose hemiacetal hydroxyl is attacked by the catalyst and protonated rapidly, and the electronegativity of the oxygen after being positively charged is greater, thereby rapidly increasing the positive charge of the anomeric carbon atom. In order to maintain its own stability, the anomeric carbon atom quickly loses a molecule of water to form an anomeric carbon cation. The nucleophilic process of n-butanol to the anomeric carbon cation generates butyl monoglycoside, which is further reacted with glucose to generate the product. The product is modified with maleic anhydride, and the anhydride group of maleic anhydride is ring-opened with -OH to increase the carboxyl group, thereby obtaining butyl glycoside. The hydroxyl group of butyl glycoside (alkyl glycoside) in the application reacts with NCO in chain extension to increase non-ionic surfactant, and the carboxyl group in butyl glycoside adjusts pH and increases its anionic property. Therefore, the butyl glycoside with emulsifying and penetrating properties is introduced into polyurethane to increase the emulsion stability of polyurethane and improve the permeability of polyurethane.

[0027] (4) Based on the butyl monoglycoside further reacted with glucose, the obtained product is modified with maleic anhydride, and the obtained carboxylic acid is reacted with the hydroxyl group in citric acid to introduce carboxylic acid into the system and increase the anionic property of the obtained product (the subsequent polyurethane increases the pH to 7-8).

[0028] (5) The cortex phellodendri is reacted with phosphorus trichloride. Since the cortex phellodendri has a large number of phenolic hydroxyl groups, it reacts with P-Cl to make the obtained cortex phellodendri more easily carbonized in phosphorus compounds, and the carbonization amount is increased. The introduction of ethanolamine increases the hydroxyl content in the system and improves the carbon content of the carbonization agent.

[0029] (6) Butyl glycoside end point determination: take 0.5 mL of reaction mixture with a graduated test tube, dilute with 2.0 mL of distilled water, cool with running water, measure the pH value of the reaction mixture with precise pH test paper, adjust the pH to 12 with 2 mol / L sodium hydroxide solution, add 1 ml of prepared reagent, heat in the water area of 80-90℃ for 40-60s, and observe the experimental phenomenon. The prepared reagent is light blue, which is because the reaction forms stable complex ion CuY 2- , which has strong complexing ability CuY 2- , thereby preventing the formation of Cu hydroxide. Because the complex ion formed by EDTA and Cu+ is relatively weak, it cannot prevent Cu +A small amount of soluble ion oxide precipitate is generated, so that the experimental phenomenon can be observed without interference, that is, the color of the solution can be obviously observed from light blue to brick red or brick red precipitate Cu2O is generated.

[0030] The prepared reagent is: 8.3g of copper sulfate pentahydrate and 18.6g of ethylenediaminetetraacetic acid, which are added to 800ml of distilled water to prepare a solution; 20g of sodium hydroxide is added to 200ml of distilled water to prepare a solution; the latter solution is poured into the former solution while stirring; if there is a precipitate, filter it out to keep the clear night, and the prepared reagent is light blue.

[0031] (6) During the reaction process, the viscosity of the reaction system should be observed at any time, and if the viscosity is too large, acetone should be added in time to reduce the viscosity, and the parts are equivalent to g, kg, etc.

[0032] 7) Because of the unique optical properties of the coumarin functional group, it can undergo photodimerization and photodepolymerization under irradiation of different wavelengths of ultraviolet light, and without the need to add any catalyst, a part of light is absorbed to achieve the purpose of light resistance. DETAILED DESCRIPTION

[0033] The application will be further described below with examples, and the mimosa bark extract used is Haolong Chemical Leather Mimosa ME from South Africa.

[0034] The chemical materials not specified by the manufacturer involved in the embodiments of the application can be replaced by the same products of the brand of Maikelin.

[0035] Example 1

[0036] The preparation method of the fire-retardant, light-resistant, low-VOC and easily permeable waterborne polyurethane coating is characterized by:

[0037] (a) 16 parts of polytetrahydrofuran ether glycol and 16 parts of polypropylene glycol (the molecular weight of polytetrahydrofuran ether glycol and polyethylene glycol is 2000g / mol) are added to a reaction container, and after mixing, they are stirred and dried at 120℃ for 1h to remove water, and then cooled to 85℃, 15 parts of isophorone diisocyanate (IPDI) and 0.2 parts of dibutyltin dilaurate are added, and stirred at 85℃ for 1h to obtain a polyurethane prepolymer;

[0038] (b) To the polyurethane prepolymer, add 3 parts of hyperbranched flame retardant for primary chain extension, stir for 1 h, and cool the system to 58°C. Then add 1 part of dimethylol propionic acid (DMPA) for secondary chain extension, react for 0.5 h, cool to 40°C, add 1 part of alkyl glycoside, react for 0.5 h, add 0.2 parts of coumarin derivative, react for 1 h at 60°C, add 0.2 parts of charring agent, stir for 1 h at 50°C, add 2 parts of triethylamine, react for 0.5 h at 50°C, add 2 parts of acetone (may be increased slightly according to the actual system, the same below), stir to reduce the viscosity, then cool to 25°C, add 115 parts of water, adjust the stirrer speed to 2000 r / min, react for 0.5 h, adjust the pH to 7, add 14 parts of saturated sodium bisulfite (40%) and 1 part of ethyl carbamate at room temperature, filter and precipitate, separate the layers, take the upper layer as the polyurethane emulsion, adjust the pH to 7-8, and the flame-retardant, light-resistant, low-VOC, easily permeable waterborne polyurethane coating is obtained.

[0039] Preparation method of hyperbranched flame retardant:

[0040] (a) Preparation of intermediate: take 300 parts of tetrahydrofuran in a reaction vessel, heat to 50°C, add 63 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 27 parts of maleic anhydride (MA) to the reaction vessel, stir for 6 h at 50°C, and return to the reflux condenser to obtain a light yellow liquid, which is the intermediate solution. Dry the intermediate solution at 30°C for 9 h to obtain the intermediate product.

[0041] (b) Preparation of branched flame retardant: take 31 parts of intermediate, 13 parts of diisopropanolamine (DIPA) and 0.3 parts of p-toluenesulfonic acid from step (a) and dissolve them in 10 parts of N,N-dimethylformamide. After mixing, react in a reaction vessel at 120°C with stirring for 6 h to obtain a black-red liquid. Transfer it to a beaker and vacuum dry at 85°C for 8 h to constant weight to obtain the hyperbranched flame retardant.

[0042] The preparation method of the butyl glycoside (alkyl glycoside) is as follows: 2 parts of n-butanol and 0.5 parts of dodecylbenzenesulfonic acid are added into a 250 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, and stirred thoroughly, and then slowly heated to 100°C; 1 part of glucose is added into the flask for reaction, and the reflux constant temperature reaction is controlled for 30 min to identify the reaction end point; after determining the reaction end point, the reaction mixture is rapidly cooled to about 70°C, and sodium bicarbonate is added to adjust the pH value to 7-8; the weak alkaline solution is stirred for 15 min, and then subjected to dealcoholization under reduced pressure, with the temperature controlled at about 50°C and the vacuum degree controlled at 1.33 KPa; the dealcoholization end point is determined by the fact that one drop of n-butanol flows out every 1 min or longer; 0.5 parts of maleic anhydride is added into the system, and reacted at 60°C for 1 h; then 0.5 parts of citric acid is added, and reacted at 80°C for 1 h to obtain the butyl glycoside.

[0043] The preparation method of the carbonization agent is as follows: 1 part of Chinese juniper bark extract is added into 2 parts of phosphorus trichloride, and stirred and reacted at 50°C for 1 h; hydrogen chloride gas is generated in the system, and is absorbed by sodium hydroxide solution; after the addition is completed, the system is heated to 45°C, and stirred and reacted for 1 h to remove the HCl gas; when there is no obvious HCl gas released from the system, the system is cooled to room temperature; 0.05 parts of ethanolamine is added dropwise within 1 h, and the stirring reaction is continued at 30°C for 1 h to obtain a yellowish transparent viscous liquid, which is the carbonization agent.

[0044] The preparation method of the coumarin derivative is as follows: 10.6 parts of resorcinol, 12 parts of ethyl acetoacetate and 0.20 parts of p-toluenesulfonic acid are added into a three-necked flask, and stirred at a rotation speed of 220 r / min and heated to 70°C; as the reaction proceeds, the reaction mixture changes from colorless transparent liquid to light yellow liquid, and then to yellow viscous substance; after 2 h of reaction, the heating is stopped, the three-necked flask is removed, and the mixture in the flask is transferred to a Buchner funnel for filtration; the yellow solid crude product is washed with ice water; the crude product is recrystallized with 67% ethanol to obtain white needle-like crystals; the crystals are dried in a vacuum drying oven to obtain the coumarin derivative.

[0045] Example 2

[0046] The preparation method of the fire-retardant, light-resistant, low-VOC and water-permeable polyurethane coating is characterized in that:

[0047] (a) 18 parts of polytetrahydrofuran ether diol and 18 parts of polyethylene glycol (the molecular weight of the polyethylene glycol is 2000 g / mol; the molecular weight of the polytetrahydrofuran ether diol is 2000 g / mol) are added into a reaction container, and mixed and then dried at 130°C for 2 h to remove water; the temperature is lowered to 95°C, 20 parts of isophorone diisocyanate (IPDI) and 0.5 parts of dibutyltin dilaurate are added, and stirred and reacted at 95°C for 2 h to obtain a polyurethane prepolymer;

[0048] (b) To the polyurethane prepolymer, add 4 parts of hyperbranched flame retardant for primary chain extension, stir for 2 h, cool the system to 68 °C, add 2 parts of dimethylol propionic acid (DMPA) for secondary chain extension, react for 1.5 h, cool to 50 °C, add 3 parts of alkyl glycoside, react for 1.5 h, add 0.5 parts of coumarin derivative, react for 2 h at 90 °C, add 0.5 parts of charring agent, stir for 1 h at 60 °C, add 4 parts of triethylamine, react for 1.5 h, add 3 parts of acetone to reduce the viscosity, cool to 30 °C, add 125 parts of water, adjust the stirrer speed to 2000 r / min, react for 0.6 h, adjust the pH to 7, add 16 parts of saturated sodium bisulfite (40%) and 2 parts of ethyl carbamate, react at room temperature (if necessary, appropriately increase the temperature), precipitate, adjust the pH to 7-8, and obtain the flame-retardant, light-resistant, low-VOC, easily permeable waterborne polyurethane coating.

[0049] The preparation method of the flame-retardant, light-resistant, low-VOC, easily permeable waterborne polyurethane coating is as follows:

[0050] (a) Preparation of the intermediate: take 306 parts of tetrahydrofuran in a reaction container, heat at 60 °C, add 69 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 33 parts of maleic anhydride (MA) to the reaction container, stir for 7 h at 60 °C, return to the reflux condenser, and obtain a light yellow liquid, which is the intermediate solution. Dry the intermediate solution at 40 °C for 10 h to obtain the intermediate product.

[0051] (b) Preparation of the branched flame retardant: take 33 parts of the intermediate of step (a), 15 parts of diisopropanolamine (DIPA), and 0.5 parts of p-toluenesulfonic acid, dissolve in 15 parts of N,N-dimethylformamide, mix, and react in a reaction container at 130 °C for 7 h under stirring to obtain a black-red liquid. Transfer it to a beaker and vacuum dry at 95 °C for 9 h to constant weight to obtain the hyperbranched flame retardant.

[0052] The butyl glycoside (alkyl glycoside) preparation method is as follows: 2.5 parts of n-butanol and 0.5 parts of citric acid are added into a 250 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, and stirred thoroughly, and then slowly heated to 120℃, 1 part of glucose is added into the flask for reaction, the reflux constant temperature reaction is controlled for 70 min, the reaction end point is identified, after the reaction end point is determined, the reaction mixture is rapidly cooled to about 80℃, sodium bicarbonate is added to adjust the pH value to 7-8, stirred for 15-30 min to be weakly alkaline, and then alcohol is removed under reduced pressure, the temperature is controlled to about 50℃, the vacuum degree is 1.33 KPa, and the last drop of n-butanol is taken out every 1 min or longer as the alcohol removal end point; then 0.8 parts of maleic anhydride is added into the system, and reacted for 2 h at 90℃, and then 0.8 parts of citric acid is added, and reacted for 2 h at 90℃, to obtain butyl glycoside.

[0053] The carbonization agent preparation method is as follows: 1 part of Chinese juniper bark extract is added into 3 parts of phosphorus trichloride, and stirred and reacted for 2 h at 60℃, hydrogen chloride gas is generated in the system, and is absorbed by sodium hydroxide solution; after the addition is completed, the system is heated to 50℃, and stirred and reacted for 2 h to remove HCl gas; when there is no obvious HCl gas released from the system, the system is cooled to room temperature, 0.1 parts of ethanolamine is added dropwise within 1 h, and the stirring and reaction is continued for 2 h at 50℃, to obtain a yellowish transparent viscous liquid, which is the carbonization agent.

[0054] The coumarin derivative preparation method is as follows: 10.6 parts of resorcinol, 14 parts of ethyl acetoacetate and 0.4 parts of p-toluenesulfonic acid are added into a three-necked flask, and stirred at a rotation speed of 220 r / min and heated to 90℃; as the reaction proceeds, the reaction mixture changes from colorless transparent liquid to light yellow liquid, and then to yellow viscous substance; after 3 h of reaction, the heating is stopped, the three-necked flask is taken out, and the mixture in the flask is transferred to a Buchner funnel for filtration, and then washed with ice water to obtain yellow solid crude product; the crude product is recrystallized with 67% ethanol to obtain white needle-shaped crystals, which are dried in a vacuum drying oven to obtain the coumarin derivative.

[0055] Example Three

[0056] The preparation method of the fire-retardant, light-resistant, low-VOC and easily permeable waterborne polyurethane coating is characterized in that:

[0057] (a) 17 parts of polytetrahydrofuran ether diol and 17 parts of polypropylene glycol (the polyols are polypropylene glycol with a molecular weight of 2000 g / mol, and the polytetrahydrofuran ether diol has a molecular weight of 2000 g / mol) are added into a reaction container, and then mixed and dried at 125℃ for 1.5 h to remove water, and then cooled to 90℃, 17.5 parts of isophorone diisocyanate (IPDI) and 0.35 parts of dibutyltin dilaurate are added, and stirred and reacted for 1.5 h at 90℃ to obtain a polyurethane prepolymer;

[0058] (b) To the polyurethane prepolymer, add 3.5 parts of hyperbranched flame retardant for primary chain extension, stir for 1.5 h, and cool the system to 62°C. Then add 1.5 parts of dimethylol propionic acid (DMPA) for secondary chain extension, react for 1 h, cool to 45°C, add 2 parts of alkyl glycoside, react for 1 h, add 0.35 parts of coumarin derivative, react for 1.5 h at 75°C, add 0.35 parts of charring agent, stir for 1 h at 55°C, add 3 parts of triethylamine, react for 1 h, add 2.5 parts of acetone to reduce the viscosity, cool to 25°C, add 120 parts of water, adjust the stirring speed to 2000 r / min, react for 0.55 h, adjust the pH to 7, add 15 parts of saturated sodium bisulfite (40%) and 1.5 parts of urethane, react at room temperature (if necessary, appropriately increase the temperature), filter the precipitate, separate the liquid, take the upper layer as the polyurethane emulsion, adjust the pH to 7-8, and obtain the flame-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating.

[0059] The preparation method of the flame-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating is as follows:

[0060] (a) Preparation of the intermediate: take 303 parts of tetrahydrofuran in a reaction container, heat at 55°C, add 66 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 30 parts of maleic anhydride (MA) to the reaction container, stir for 6.5 h at 55°C, and return to the reflux condenser to obtain a light yellow liquid, which is the intermediate solution. Dry the intermediate solution at 35°C for 9.5 h to obtain the intermediate product.

[0061] (b) Preparation of the branched flame retardant: take 32 parts of the intermediate of step (a), 14 parts of diisopropanolamine (DIPA), and 0.4 parts of p-toluenesulfonic acid, dissolve in 12.5 parts of N,N-dimethylformamide, mix, and react in a reaction container at 125°C for 6.5 h under stirring to obtain a black-red liquid. Transfer the liquid to a beaker, and vacuum dry at 90°C for 8.5 h to constant weight to obtain the hyperbranched flame retardant.

[0062] The preparation method of the butyl glycoside is as follows: 2.25 parts of n-butanol and 0.5 parts of anhydrous aluminum chloride are added into a 250 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, and stirred thoroughly, and then slowly heated to 110°C; 1 part of glucose is added into the flask for reaction, and the reflux constant temperature reaction is controlled for 50 min to identify the reaction end point; after the reaction end point is determined, the reaction mixture is rapidly cooled to about 75°C, sodium bicarbonate is added to adjust the pH value to 7-8, and stirred for 15-30 min to be weakly alkaline; the n-butanol is removed under reduced pressure, the temperature is controlled at about 50°C, the vacuum degree is 1.33 KPa, and the end point of the removal of n-butanol is determined by the fact that one drop of n-butanol flows out every 1 min or longer; 0.65 parts of maleic anhydride is added into the system, and reacted at 75°C for 1.5 h; then 0.65 parts of citric acid is added, and reacted at 85°C for 1.5 h to obtain the butyl glycoside.

[0063] The preparation method of the carbonization agent is as follows: 1 part of Chinese wattle bark extract is added into 2.5 parts of phosphorus trichloride, and stirred and reacted at 55°C for 1.5 h; hydrogen chloride gas is generated in the system, and is absorbed by sodium hydroxide solution; after the addition is completed, the system is heated to 45°C, and stirred and reacted for 1.5 h to remove the HCl gas; when there is no obvious HCl gas released from the system, the system is cooled to room temperature; 0.05 parts of ethanolamine is added dropwise within 1 h, and the stirring and reaction is continued at 40°C for 1.5 h to obtain a yellowish transparent viscous liquid, which is the carbonization agent.

[0064] The preparation method of the coumarin derivative is as follows: 10.6 parts of resorcinol and 13 parts of ethyl acetoacetate are added into a three-necked flask, 0.3 parts of p-toluenesulfonic acid is added, and the mixture is stirred at a rotating speed of 220 r / min and heated to 80°C; as the reaction proceeds, the reaction mixture changes from colorless transparent liquid to light yellow liquid, and then to yellow viscous substance; after 2.5 h, the heating is stopped, the three-necked flask is removed, and the mixture in the flask is transferred to a Buchner funnel for filtration; the yellow solid crude product is washed with ice water to obtain a white needle-like crystal; the crystal is dried in a vacuum drying oven to obtain the coumarin derivative.

[0065] The VOC determination method is as follows: the metal flat pan is baked in an oven at 105±2°C for 30 min, and then placed in a desiccator until use.

[0066] After the polyurethane is mixed, it is spread on a metal flat pan, and then placed in a constant temperature and humidity chamber at a temperature of 23±2°C and a humidity of 50±5% for 24 h; then the pan is baked in an oven at 105±2°C for 60 min; two parallel tests are performed.

[0067] The mass m1 before heating (the sum of the mass of the metal container m0 and the reactants) and the mass m2 after heating are measured.

[0068]

[0069] ​Example 2 of comparative patent 202011624359.8;

[0070] Carbon residue and expansion height:

[0071] Carbon residue and expansion height determination at 500℃ was carried out using a muffle furnace sample, about 1g of different flame retardant samples was put into each crucible, and the muffle furnace was set to an initial temperature of 100℃, a holding temperature of 500℃, and a holding time of 10min. After the time, it was taken out and placed in a drying box to cool to room temperature, weighed, and the sample expansion height was measured, and the carbon residue was measured.

[0072] Emulsion stability: The storage stability of the emulsion for 36 months was simulated using a high-speed centrifuge, which was rotated at a speed of 3500r / min for 20min, and the situation was observed. If there was no precipitation phenomenon in the emulsion, it was considered that the emulsion was stable in nature.

[0073] ASTM E13541990 (2004 standard) was used to determine the maximum heat release rate pkHHR kW / m 2 , THR total heat release MJ / m 2 , and THR total heat release MJ / m 2 .

[0074] Dripping test

[0075] (1) Sample preparation: The prepared PU film was placed in a constant temperature and humidity chamber set at 23℃±0.5℃ and 50%±5% humidity for 48h, then taken out and cut into 110cm×10cm×3mm samples, and 2 sets of samples were prepared, each set containing 5 samples.

[0076] (2) Parameter setting: about 5mm was clamped from the upper end, so that the sample was vertically downward, the lower end of the sample was placed on a rosin wood board, about 0.3g of absorbent cotton was placed on the wood board, and the absorbent cotton was evenly placed on the wood board. Adjust the gas flow to 105±5mL / min, so that the height of the flame reaches 20±1mm. Set the burning time to 10s.

[0077] (3) Flame application record: after setting the parameters, start the flame application and ignition, after 10s of ignition, press the afterflame time start button, when the sample burns out and only sparks remain, press the afterflame burnout button, enter the afterglow time, and press the afterglow time end button when it is completely extinguished. Record the afterflame time and afterglow time of the burning.

[0078] (4) Dripping observation: during the burning process, pay attention to observe whether the burning produces drips, and whether the drips falling on the absorbent cotton below will cause secondary combustion, and record the observation results.

[0079] The penetration time is determined by dropping one drop of polyurethane onto the surface of the leather to be coated, and observing the time for the emulsion to disappear from the surface using a JYW-200A full-automatic surface tension meter.

[0080] Light resistance is determined by measuring the color change under UV light for 48 h under simulated sunlight, and observing the color change using a Gretag Macbeth Coloreye spectrophotometer (D65 light source, 10-degree observer, including UV).

[0081]

[0082] Table 1 Properties of polyurethane films

[0083]

[0084] Comparative Example 2 of the comparative patent, the emulsions obtained in Examples 1 to 3 of the present application have good stability. As can be seen from Table 1, the present application does not produce molten droplets during combustion, and the pkHHR, THR and surface tension are all lower than those of the comparative example, indicating good flame retardance and permeability (low surface tension indicates good wettability), and in combination with the penetration time, the shorter the penetration time, the better the permeability. The light resistance of the present application is better than that of ordinary light resistance, but not the highest in the industry.

[0085] Table 2 Properties of polyurethane films without additional materials (Example 2)

[0086]

[0087]

[0088] As can be seen from Table 2, the hyperbranched flame retardant, diisopropanolamine, maleic anhydride and the char-forming agent all play a role in flame retardance.

[0089] Table 3 Properties of polyurethane films without additional materials (Example 2)

[0090] Property No material added VOC / % 10.2 No sodium bisulfite added VOC / % 2.1 No ethyl carbamate added

[0091] As can be seen from Table 3, both saturated sodium bisulfite and ethyl carbamate improve the VOC index, indicating their effectiveness in reducing polyurethane.

[0092] Table 4 Properties of polyurethane films without additional materials (Example 2)

[0093] Property No material added Surface tension (mN / m) 78.23 No butyl glycoside added Penetration time (s) 12.3 No butyl glycoside added Surface tension (mN / m) 56.42 Butyl glycoside added, no maleic anhydride added this pass Penetration time (s) 9.8 Butyl glycoside added, no maleic anhydride added this pass Surface tension (mN / m) 65.47 Butyl glycoside added, no citric acid added Penetration time (s) 10.2 Butyl glycoside added, no citric acid added

[0094] As can be seen from Table 4, butyl glycoside, maleic anhydride and citric acid all have good effects.

[0095] Table 5 Data of hyperbranched flame retardants​

[0096] Example 1 Example 2 Example 3 Comparative patent Char yield / % 74.7 75.3 77.4 72.6 Swelling height / cm 5.93 5.89 5.93 5.69

[0097] From Table 5, it can be seen that the char yield and expansion height of the present application are superior to the comparative file, showing better char yield and expansion height.

[0098] Table 6 Performance of partial materials on hyperbranched flame retardant (based on Example 3)

[0099]

[0100] From Table 6, it can be seen that diisopropanolamine and 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide partial materials play a role in the expansion effect of the intumescent flame retardant.

Claims

1. A process for the preparation of key materials for use in flame retardant, lightfast, low VOC, easily permeable waterborne polyurethane coatings, characterized in that: The key materials include: hyperbranched flame retardant, butyl glycoside, char forming agent and coumarin derivative; The preparation method of the hyperbranched flame retardant is as follows: (a) Preparation of intermediate: 300-306 parts of tetrahydrofuran are taken in a reaction container, heated at 50-60 DEG C, 63-69 parts of 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 27-33 parts of maleic anhydride (MA) are added to the reaction container, 50-60 DEG C is returned to reflux condenser device and stirred for 6-7 h to obtain a light yellow liquid, which is the intermediate solution, the intermediate solution is dried at 30-40 DEG C for 9-10 h to obtain the intermediate product; (b) Preparation of hyperbranched flame retardant: 31-33 parts of intermediate, 13-15 parts of diisopropanolamine (DIPA) and 0.3-0.5 parts of p-toluenesulfonic acid are weighed in N, N-dimethylformamide 10-15 parts, mixed and reacted in a reaction container at 120-130 DEG C under stirring for 6-7 h to obtain a black red liquid, which is transferred to a beaker and vacuum dried at 85-95 DEG C for 8-9 h to constant weight, thereby obtaining the hyperbranched flame retardant; The preparation method of the butyl glycoside is as follows: 2-2.5 parts of n-butanol and 0.5 parts of acid catalyst are added into a 250 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, fully stirred and slowly heated to 100-120 DEG C, 1 part of glucose is added into the flask for reaction, the reaction endpoint is identified by controlling the reflux constant temperature reaction for 30-70 min, after determining the reaction endpoint, the reaction mixture is rapidly cooled to 70-80 DEG C, sodium bicarbonate is added to adjust the pH value to 7-8, stirred for 15-30 min to be weakly alkaline, and the butanol is removed under reduced pressure, the temperature is controlled at about 50 DEG C, the vacuum degree is 1.33 KPa, and the butanol is removed until one drop of butanol is discharged every 1 min or longer, then 0.5-0.8 parts of maleic anhydride is added into the system, reacted at 60-90 DEG C for 1-2 h, and then 0.5-0.8 parts of citric acid is added, reacted at 80-90 DEG C for 1-2 h to obtain butyl glycoside; The preparation method of the char forming agent is as follows: 1 part of jing bush bark tannin is added with 2-3 parts of phosphorus trichloride, stirred at 50-60 DEG C for 1-2 h, hydrogen chloride gas is generated in the system, which is absorbed by sodium hydroxide solution, after the addition is completed, the system is heated to 45-50 DEG C, and the stirring reaction is carried out for 1-2 h to remove HCl gas, when there is no obvious HCl gas released from the system, the system is cooled to room temperature, 0.05-0.1 parts of ethanolamine is added dropwise within 1 h, and the stirring reaction is continued at 30-50 DEG C for 1-2 h to obtain a yellowish transparent viscous liquid, which is the char forming agent. The coumarin derivative preparation method is as follows: in a three-neck flask, 10.6 parts of resorcinol, 12-14 parts of ethyl acetoacetate, and 0.20-0.4 parts of p-toluenesulfonic acid are added, and stirring is carried out at a rotation speed of 220 r / min while heating to 70-90 ℃; as the reaction proceeds, the reactants change from colorless transparent liquid to light yellow liquid, and then to yellow viscous substance; after 2-3 h of reaction, heating is stopped, the three-neck flask is removed, and the mixture in the flask is transferred to a Buchner funnel for filtration; the yellow solid crude product is obtained after washing with ice water; the crude product is recrystallized with 67% ethanol to obtain white needle-shaped crystals; and the crystals are dried in a vacuum drying oven to obtain the coumarin derivative.

2. The preparation method of the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating key material according to claim 1, wherein the preparation method of the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating is as follows: (a) 16-18 parts of polytetrahydrofuran ether diol and 16-18 parts of polyhydric alcohol are added to a reaction container, and the mixture is stirred and dried at 120-130 ℃ for 1-2 h to remove water; the temperature is lowered to 85-95 ℃, 15-20 parts of isophorone diisocyanate and 0.2-0.5 parts of dibutyltin dilaurate are added, and stirring reaction is carried out at 85-95 ℃ for 1-2 h to obtain a polyurethane prepolymer; (b) 3-4 parts of hyperbranched flame retardant are added to the polyurethane prepolymer for primary chain extension, and stirring reaction is carried out for 1-2 h; the system is cooled to 58-68 ℃, 1-2 parts of dimethylol propionic acid is added for secondary chain extension, and reaction is carried out for 0.5-1.5 h; the temperature is lowered to 40-50 ℃, 1-3 parts of butyl glycoside is added, and reaction is carried out for 0.5-1.5 h; 0.2-0.5 parts of coumarin derivative is added, and reaction is carried out at 60-90 ℃ for 1-2 h; 0.2-0.5 parts of charring agent is added, and stirring reaction is carried out at 50-60 ℃ for 1 h; 2-4 parts of triethylamine is added, and reaction is carried out for 0.5-1.5 h; 2-3 parts of acetone is added to reduce the viscosity; the temperature is lowered to 25-30 ℃, 115-125 parts of water is added, the stirring speed is adjusted to 2000 r / min, and reaction is carried out for 0.5-0.6 h; the pH is adjusted to 7; 14-16 parts of 40% saturated sodium bisulfite and 1-2 parts of ethyl carbamate are added for room temperature reaction; the precipitate is filtered and separated; the upper layer is taken as the polyurethane emulsion; the pH is adjusted to 7-8; and the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating is obtained.

3. The preparation method of the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating key material according to claim 1, wherein the acidic catalyst is any one of dodecylbenzenesulfonic acid, citric acid, and anhydrous aluminum chloride.

4. The preparation method of the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating key material according to claim 2, wherein the polyhydric alcohol is any one of polypropylene glycol and polyethylene glycol, and the molecular weight of each is 2000 g / mol.

5. The preparation method of the fire-retardant, light-resistant, low-VOC, and easily permeable waterborne polyurethane coating key material according to claim 2, wherein the molecular weight of the polytetrahydrofuran ether diol is 2000 g / mol.

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