Flame-retardant and ultraviolet-shielding waterborne polyurethane and method for preparing the same

Abstract

The application discloses a kind of flame-retardant and ultraviolet shielding water-based polyurethane and preparation method thereof.It is polymerized by diisocyanate, polyol, phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer, chain extender and hydrophilic chain extender;The method is that aromatic intermediate is obtained by reacting p-aminophenol and 2,4-dihydroxybenzaldehyde;Phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer is obtained by reacting aromatic intermediate and 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide;Diisocyanate, polyol and hydrophilic chain extender are reacted, phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer and chain extender are added, acetone is added, and prepolymer is obtained by continuing to react;The prepolymers are cooled, neutralized by neutralizing agent, poured into deionized water, stirred, acetone is removed, and the flame-retardant and ultraviolet shielding water-based polyurethane is obtained.The preparation method is simple, the obtained polyurethane has good flame-retardant and ultraviolet shielding performance, and has wide application prospect in the fields of cable surface treatment and fabric finishing agent.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of polyurethane and its preparation method, especially a kind of flame-retardant and ultraviolet shielding water-based polyurethane and its preparation method. BACKGROUND

[0002] Water-based polyurethane (WPU) is a new type of polyurethane with water as dispersion medium instead of organic solvent, which has the advantages of environmental protection, chemical resistance, wear resistance, etc., and is widely used in coatings, adhesives and finishing agents, etc. However, the traditional WPU has low flame-retardant performance, which limits its application. At present, the methods for flame-retardant modification of WPU mainly include the introduction of additive flame retardants and reactive flame retardants. Compared with additive flame retardants, reactive flame retardants are introduced into the molecular chain of WPU by participating in the synthesis process, so as to improve the flame-retardant performance while maintaining the unique performance of polyurethane. At present, there are many kinds of reactive flame retardants reported, such as phosphorus-based, nitrogen-based and silicon-based, etc. Although these reactive flame retardants improve the flame-retardant performance of WPU, the char-forming efficiency is still not high, and the melt dripping during combustion process cannot be effectively inhibited. In recent years, reactive flame retardants based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) have good performance in improving the char-forming performance of WPU and inhibiting melt dripping, etc. However, the reactive flame retardants based on DOPO are still in the initial stage, and their dosage in WPU is often large, which will damage the mechanical properties of WPU. Moreover, when WPU is used in the fields of coatings, adhesives and finishing agents, etc., it will inevitably be subjected to long-term light irradiation, which will cause ultraviolet aging and damage the comprehensive use performance. However, when WPU is modified for flame retardation, little consideration is given to the practical performance of ultraviolet shielding. Therefore, it is a difficult problem to be solved at present to simultaneously improve the flame-retardant performance and ultraviolet shielding performance without affecting the mechanical properties of WPU. SUMMARY

[0003] In order to overcome the problems in the background art, the present application provides a kind of flame-retardant and ultraviolet shielding water-based polyurethane and its preparation method. The preparation method of the present application is simple, and the obtained polyurethane has good flame-retardant and ultraviolet shielding performance, which has broad application prospects in the fields of cable surface treatment, fabric finishing agent, etc.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application to solve its technical problems is as follows:

[0005] I. A kind of flame-retardant and ultraviolet shielding water-based polyurethane:

[0006] which is mainly polymerized from diisocyanate, polyol, phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer, chain extender and hydrophilic chain extender, and the chemical structure formula is as shown below:

[0007]

[0008] The mass content of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer in the polyurethane molecule is 3-12wt%, and the chemical structural formula is as follows:

[0009]

[0010] The hydroxyl (-OH) on the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer molecule reacts with the isocyanate group (-NCO) in the chain extension reaction to form an urethane bond (-NH-COO-).

[0011] The diisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate, and toluene diisocyanate.

[0012] The polyol is at least one of polypropylene glycol, polyethylene glycol, and polybutylene adipate.

[0013] The chain extender is at least one of 1,4-butanediol, ethylene glycol, and 1,5-pentanediol.

[0014] The hydrophilic chain extender is at least one of 2,2-dimethylol propionic acid and 2,2-dimethylol butyric acid.

[0015] II. A method for preparing a flame-retardant and ultraviolet shielding water-based polyurethane, comprising the following steps:

[0016] Step 1) Using anhydrous ethanol as a solvent and glacial acetic acid as a catalyst, p-aminophenol, 2,4-dihydroxybenzaldehyde, glacial acetic acid, and anhydrous ethanol are stirred and reacted at 60-70℃ for 3-5h, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate is colorless, and vacuum dried to obtain an aromatic intermediate;

[0017] Step 2) Using tetrahydrofuran as a solvent, the aromatic intermediate obtained in step (1) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are stirred and reacted at 10-15℃ for 10-12h, poured into deionized water, vacuum filtered, washed with deionized water until the filtrate is colorless, and vacuum dried to obtain a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer;

[0018] Step 3) Under a nitrogen atmosphere, diisocyanate, polyol, hydrophilic chain extender, and catalyst are stirred and reacted at 70-85℃ for 1-3h, the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer obtained in step (2) and chain extender are added and warmed to 80-95℃, acetone is added, and the reaction is continued for 3-7h to obtain a prepolymer;

[0019] Step 4) The prepolymer obtained in step (3) is cooled to 45-50℃, a neutralizing agent is added and neutralized for 20-30 min, poured into deionized water, stirred at a speed of 500-800 r / min for 20-30 min, and the acetone is removed by rotary evaporation to obtain the flame-retardant and ultraviolet-shielding waterborne polyurethane.

[0020] The molar ratio of the p-aminophenol and 2,4-dihydroxybenzaldehyde in the step (1) is 1-1.05:1.

[0021] The amount of the glacial acetic acid is 0.1-0.5 wt% of the total mass of the p-aminophenol and 2,4-dihydroxybenzaldehyde.

[0022] The molar ratio of the aromatic intermediate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the step (2) is 1:1-1.05.

[0023] The amount of the acetone is 15-30 wt% of the total mass of the diisocyanate, the polyol, the hydrophilic chain extender and the catalyst.

[0024] The weight ratio of the diisocyanate, the polyol, the hydrophilic chain extender, the phosphorus-nitrogen-containing flame-retardant and ultraviolet-shielding functional monomer, the catalyst, the chain extender and the neutralizing agent in the step (3) and step (4) is: 13-20:12-72:2.4-3.5:1.8-7.2:0.026-0.1:1.2-2.7:2.1-3.5.

[0025] The catalyst in the step (3) is at least one of dibutyltin dilaurate and stannous octoate.

[0026] The molecular weight of the polyol in the step (3) is 1000-4000 g / mol.

[0027] The neutralizing agent in the step (4) is at least one of triethylamine, triethanolamine and N-methyl diethanolamine.

[0028] The molar ratio of the isocyanate groups (-NCO) of the diisocyanate to the total hydroxyl groups (-OH) in the polyol, the hydrophilic chain extender, the phosphorus-nitrogen-containing flame-retardant and ultraviolet-shielding functional monomer and the chain extender is 1.0-1.6:1.

[0029] The beneficial effects of the present application are:

[0030] The preparation method is simple, the obtained polyurethane has a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer introduced into the molecular main chain, the monomer is a DOPO-based aromatic Schiff derivative containing phenolic hydroxyl groups, the monomer can improve the charring efficiency and inhibit melt dripping, and further improve the flame-retardant performance. The special molecular structure and rich benzene ring groups of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer can endow the polyurethane with excellent ultraviolet shielding performance. In addition, the phenolic hydroxyl groups arranged in the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer effectively increase the physical crosslinking based on hydrogen bonds, thereby avoiding damage to the mechanical properties, and even improving the yield strength and elastic modulus, and therefore, the monomer has a wide application prospect in the fields of cable surface treatment and fabric finishing agent. DETAILED DESCRIPTION

[0031] The application will be further described in detail below in combination with specific examples.

[0032] The examples and the comparison of the application are as follows:

[0033] In the examples and the comparative examples, 2,4-dihydroxybenzaldehyde (98%), DOPO (97%), polypropylene glycol 2000, 2,2-dimethylol propionic acid (98%), dibutyltin dilaurate (95%), 1,4-butanediol (99.5%), triethylamine (99%), p-aminophenol (98%), isophorone diisocyanate (99%), anhydrous ethanol, glacial acetic acid and tetrahydrofuran are commercially available materials.

[0034] The flame-retardant performance test method: the limiting oxygen index (LOI) is tested according to the standard ASTM D2863, and the UL-94 vertical burning is tested according to the standard ASTM D3801.

[0035] The ultraviolet shielding performance test method: PerkinElmer Lambda 900 ultraviolet-visible spectrophotometer is used for testing.

[0036] Example 1:

[0037] (1) 13.8 g of p-aminophenol, 10.9 g of 2,4-dihydroxybenzaldehyde, 60 μL of glacial acetic acid and 100 mL of anhydrous ethanol are stirred and reacted at 60°C for 3 h, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate is colorless, and vacuum dried to obtain an aromatic intermediate;

[0038] (2) 22.9 g of the aromatic intermediate obtained in step 1), 21.6 g of DOPO and 100 mL of tetrahydrofuran are stirred and reacted at 10-15°C for 12 h, poured into 300 mL of deionized water, vacuum filtered, washed with deionized water until the filtrate is colorless, and vacuum dried to obtain a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer;

[0039] (3) Under nitrogen atmosphere, 19 g of isophorone diisocyanate, 30 g of polypropylene glycol 2000, 2.8 g of 2,2-dimethylol propionic acid and 0.027 g of dibutyl tin dilaurate were stirred and reacted at 80°C for 2 h, 1.8 g of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer obtained in step 2) and 2.1 g of 1,4-butanediol were added and warmed to 90°C, 20 mL of acetone was added to adjust the viscosity of the system, and the reaction was continued for 3 h to obtain a prepolymer;

[0040] (4) The prepolymer obtained in step 3) was cooled to 50°C, 2.1 g of triethylamine was added and neutralized for 30 min, poured into 107 mL of deionized water, stirred at 500 r / min for 30 min, and the acetone was removed by rotary evaporation to obtain a flame-retardant and ultraviolet shielding waterborne polyurethane, which was recorded as FRWPU3.

[0041] Example 2:

[0042] (1) 13.8 g of p-aminophenol, 10.9 g of 2,4-dihydroxybenzaldehyde, 60 μL of glacial acetic acid and 100 mL of anhydrous ethanol were stirred and reacted at 60°C for 3 h, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate was colorless, and vacuum dried to obtain an aromatic intermediate;

[0043] (2) 22.9 g of the aromatic intermediate obtained in step 1), 21.6 g of DOPO and 100 mL of tetrahydrofuran were stirred and reacted at 10-15°C for 12 h, poured into 300 mL of deionized water, vacuum filtered, washed with deionized water until the filtrate was colorless, and vacuum dried to obtain a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer;

[0044] (3) Under nitrogen atmosphere, 19 g of isophorone diisocyanate, 30 g of polypropylene glycol 2000, 2.8 g of 2,2-dimethylol propionic acid and 0.027 g of dibutyl tin dilaurate were stirred and reacted at 80°C for 2 h, 3.6 g of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer obtained in step 2) and 1.8 g of 1,4-butanediol were added and warmed to 90°C, 20 mL of acetone was added to adjust the viscosity of the system, and the reaction was continued for 3 h to obtain a prepolymer;

[0045] (4) The prepolymer obtained in step 3) was cooled to 50°C, 2.1 g of triethylamine was added and neutralized for 30 min, poured into 110 mL of deionized water, stirred at 500 r / min for 30 min, and the acetone was removed by rotary evaporation to obtain a flame-retardant and ultraviolet shielding waterborne polyurethane, which was recorded as FRWPU6.

[0046] Example 3:

[0047] (1) 13.8 g of p-aminophenol, 10.9 g of 2,4-dihydroxybenzaldehyde, 60 μL of glacial acetic acid and 100 mL of anhydrous ethanol were stirred at 60°C for 3 h, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate was colorless, and vacuum dried to obtain an aromatic intermediate;

[0048] (2) 22.9 g of the aromatic intermediate obtained in step 1), 21.6 g of DOPO and 100 mL of tetrahydrofuran were stirred at 10-15°C for 12 h, poured into 300 mL of deionized water, vacuum filtered, washed with deionized water until the filtrate was colorless, and vacuum dried to obtain a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer;

[0049] (3) Under a nitrogen atmosphere, 19 g of isophorone diisocyanate, 30 g of polypropylene glycol 2000, 2.8 g of 2,2-dimethylol propionic acid and 0.027 g of dibutyl tin dilaurate were stirred at 80°C for 2 h, 5.4 g of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer obtained in step 2) and 1.5 g of 1,4-butanediol were added and warmed to 90°C, 20 mL of acetone was added to adjust the viscosity of the system, and the reaction was continued for 3 h to obtain a prepolymer;

[0050] (4) The prepolymer obtained in step 3) was cooled to 50°C, 2.1 g of triethylamine was added and neutralized for 30 min, poured into 113 mL of deionized water, stirred at 500 r / min for 30 min, and the acetone was removed by rotary evaporation to obtain a flame-retardant and ultraviolet shielding waterborne polyurethane, denoted as FRWPU9.

[0051] Example 4:

[0052] (1) 13.8 g of p-aminophenol, 10.9 g of 2,4-dihydroxybenzaldehyde, 60 μL of glacial acetic acid and 100 mL of anhydrous ethanol were stirred at 60°C for 3 h, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate was colorless, and vacuum dried to obtain an aromatic intermediate;

[0053] (2) 22.9 g of the aromatic intermediate obtained in step 1), 21.6 g of DOPO and 100 mL of tetrahydrofuran were stirred at 10-15°C for 12 h, poured into 300 mL of deionized water, vacuum filtered, washed with deionized water until the filtrate was colorless, and vacuum dried to obtain a phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer;

[0054] (3) Under a nitrogen atmosphere, 19 g of isophorone diisocyanate, 30 g of polypropylene glycol 2000, 2.8 g of 2,2-dimethylol propionic acid and 0.027 g of dibutyl tin dilaurate were stirred at 80°C for 2 h, 5.4 g of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer obtained in step 2) and 1.5 g of 1,4-butanediol were added and warmed to 90°C, 20 mL of acetone was added to adjust the viscosity of the system, and the reaction was continued for 3 h to obtain a prepolymer;

[0055] (4) The prepolymer obtained in step 3) was cooled to 50℃, 2.1g of triethylamine was added for neutralization for 30 min, poured into 115 mL of deionized water, stirred at 500 r / min for 30 min, and the acetone was removed by rotary evaporation to obtain a flame-retardant and ultraviolet-shielding waterborne polyurethane, denoted as FRWPU12.

[0056] Comparative Example 1:

[0057] (1) Under a nitrogen atmosphere, 19 g of isophorone diisocyanate, 30 g of polypropylene glycol 2000, 2.8 g of 2,2-dimethylol propionic acid, and 0.026 g of dibutyl tin dilaurate were stirred and reacted at 80℃ for 2 h, 2.4 g of 1,4-butanediol was added and the temperature was raised to 90℃, 20 mL of acetone was added to adjust the viscosity of the system, and the reaction was continued for 3 h to obtain a prepolymer;

[0058] (2) The prepolymer obtained in step 1) was cooled to 50℃, 2.1g of triethylamine was added for neutralization for 30 min, poured into 105 mL of deionized water, stirred at 500 r / min for 30 min, and the acetone was removed by rotary evaporation to obtain a waterborne polyurethane, denoted as WPU I.

[0059] The waterborne polyurethanes obtained in the above examples and Comparative Example 1 were subjected to LOI testing, UL-94 testing, and ultraviolet-visible light transmittance testing, and the results are shown in Table 1 below:

[0060] Table 1

[0061] Sample LOI (%) UL-94 burning rating 350 nm transmittance (%) Comparative Example 1 WPU I 18.1 V-2 89.1 Example 1 FR WPU 3 22.8 V-0 0.8 Example 2 FR WPU 6 25.8 V-0 0.7 Example 3 FR WPU 9 27.0 V-O 0.6 Example 4 FR WPU 12 27.9 V-0 0.3

[0062] The test results of the examples show that the WPU I obtained in Comparative Example 1 does not contain phosphorus-nitrogen flame-retardant and ultraviolet-shielding functional monomers, has low flame-retardant performance, is prone to dripping during combustion, and has low ultraviolet light shielding performance. After introducing the phosphorus-nitrogen flame-retardant and ultraviolet-shielding functional monomers into the polyurethane main chain, the LOI is significantly improved, the UL-94 rating reaches V-0 level, the dripping phenomenon during combustion is improved, and excellent ultraviolet light shielding effect is achieved. Moreover, as the mass content of the phosphorus-nitrogen flame-retardant and ultraviolet-shielding functional monomers in the polyurethane main chain increases, the LOI becomes higher and higher, and the ultraviolet light shielding performance becomes better and better.

[0063] The above examples are only used to explain the present application, but not to limit the protection scope of the present application. Any equivalent changes or modifications made within the spirit and scope of the present application and the claims are considered to be within the protection scope of the present application.

Claims

1. A flame-retardant and UV-shielding waterborne polyurethane, characterized by: The flame-retardant and ultraviolet shielding water-based polyurethane is mainly polymerized by diisocyanate, polyhydric alcohol, phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer, chain extender and hydrophilic chain extender, and the chemical structural formula is shown in the following formula: The chain extender is 1, 4-butanediol, the hydrophilic chain extender is 2, 2-dimethylol butyric acid, the diisocyanate is isophorone diisocyanate, and the polyhydric alcohol is polypropylene glycol.

2. The flame-retardant and ultraviolet shielding water-based polyurethane according to claim 1, characterized in that: The mass content of the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer in the polyurethane is 3-12 wt%, and the chemical structural formula is shown in the following formula:

3. The flame-retardant and ultraviolet shielding water-based polyurethane according to claim 1, characterized in that: The chain extender is replaced by at least one of ethylene glycol and 1, 5-pentanediol; the hydrophilic chain extender is replaced by 2, 2-dimethylol propionic acid; the diisocyanate is replaced by at least one of hexamethylene diisocyanate and toluene diisocyanate; and the polyhydric alcohol is replaced by at least one of polyethylene glycol and polybutylene adipate.

4. A process for the preparation of the flame retardant and UV shielding waterborne polyurethane as claimed in any one of claims 1 to 3, characterized in that, The method comprises the following steps: Step 1) In anhydrous ethanol as a solvent and glacial acetic acid as a catalyst, p-aminophenol and 2, 4-dihydroxybenzaldehyde are mixed and reacted at a certain temperature, cooled to room temperature, vacuum filtered, washed with ethanol until the filtrate is colorless, and vacuum dried to obtain an aromatic intermediate; Step 2) In tetrahydrofuran as a solvent, the aromatic intermediate obtained in step 1) and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed and reacted at a certain temperature, poured into deionized water, vacuum filtered, washed with deionized water until the filtrate is colorless, and vacuum dried to obtain the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer; Step 3) Under a nitrogen atmosphere, diisocyanate, polyhydric alcohol, hydrophilic chain extender and catalyst are mixed and reacted at a certain temperature, then the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer and chain extender obtained in step 2) are added and heated, acetone is added, and the reaction is continued to obtain a prepolymer; Step 4) The prepolymer obtained in step 3) is cooled and neutralized, deionized water is added and stirred, and acetone is removed by rotary evaporation to obtain the flame-retardant and ultraviolet shielding water-based polyurethane.

5. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: In step 1), p-aminophenol and 2, 4-dihydroxybenzaldehyde are stirred and reacted at 60-70℃ for 3-5h.

6. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: In step 2), the aromatic intermediate and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are stirred and reacted at 10-15℃ for 10-12h.

7. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: In step 3), diisocyanate, polyhydric alcohol, hydrophilic chain extender and catalyst are stirred and reacted at 70-85℃ for 1-3h, then the phosphorus-nitrogen-containing flame-retardant and ultraviolet shielding functional monomer and chain extender are added and heated to 80-95℃, acetone is added, and the reaction is continued for 3-7h.

8. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: In step 4), the prepolymer is cooled to 45-50℃, a neutralizing agent is added and neutralized for 20-30min, poured into deionized water, and stirred at a speed of 500-800r / min for 20-30min.

9. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: In step 1), the molar ratio of p-aminophenol to 2, 4-dihydroxybenzaldehyde is 1-1.05:

1. In the step 2), the molar ratio of the aromatic intermediate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:1-1.05; In the step 3) and step 4), the weight ratio of diisocyanate, polyol, hydrophilic chain extender, phosphorus-containing nitrogen-containing flame-retardant and UV shielding functional monomer, catalyst, chain extender and neutralizing agent is: 13-20: 12-72: 2.4-3.5: 1.8-7.2: 0.026-0.1: 1.2-2.7: 2.1-3.

5.

10. A process for the preparation of a flame retardant and UV shielding waterborne polyurethane as claimed in claim 4, wherein: The molecular weight of the polyol in the step 3) is 1000-4000 g / mol.

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