Halogen-free reactive flame retardant, halogen-free flame-retardant waterborne polyurethane and preparation method of halogen-free reactive flame retardant
By introducing P and Si flame retardant elements of halogen-free reactive flame retardant into the aqueous polyurethane, and introducing them into the polyurethane backbone through active hydroxyl reaction, the problem of poor flame retardant performance of aqueous polyurethane is solved, and efficient flame retardant effect and safe and environmentally friendly characteristics are achieved.
Patent Information
- Application Number
- CN202510109213.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-05-06
AI Technical Summary
The flame retardant properties of existing water-based polyurethanes are extremely poor and it is difficult to meet high flame retardant requirements in the application field, especially when the combustion speed is fast and the large amount of heat energy is generated.
Using halogen-free reactive flame retardant, the flame retardant elements of P and Si are introduced into the polyurethane prepolymer, and the active hydroxyl group reacts with isocyanate to form chemical bonds, and the flame retardant elements are introduced into the polyurethane backbone, thereby improving its flame retardant performance.
It significantly improves the flame retardant properties of water-based polyurethane, can promote dehydration and carbonization, insulate heat and oxygen during the polymer combustion process, thereby achieving excellent flame retardant effects, while maintaining the characteristics of low viscosity liquids, and has the advantages of safety, environmental protection and efficient preparation.
Smart Images
Figure CN119930692A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a halogen-free reactive flame retardant, a halogen-free flame-retardant water-based polyurethane and a preparation method thereof, and belongs to the technical field of functional materials. Background Art
[0002] Waterborne polyurethane (WPU) refers to a polyurethane resin that can be dissolved or dispersed in water. It uses the gravity, surface tension and volume expansion effect of water to disperse polyurethane particles. It is widely used in furniture processing, leather processing, building materials, etc. because of its easy processing, low toxicity and environmental protection, safety and reliability, and low production cost.
[0003] As people's requirements for environmental protection increase, the advantages of waterborne polyurethane are becoming more and more obvious, and its application range is becoming wider and wider, so the performance requirements are also getting higher and higher. After drying, the limiting oxygen index of waterborne polyurethane is generally very low, usually only about 18%, so its flame retardant performance is extremely poor. Once it starts to burn, the burning speed is very fast, and a large amount of heat energy will be generated during the combustion process to promote combustion. Therefore, flame retardant treatment is required in many application fields.
[0004] Common flame retardant methods mainly include adding flame retardants and intrinsic flame retardancy. Adding flame retardants often has problems such as poor compatibility between flame retardants and substrates and uneven dispersion, which often leads to low flame retardant efficiency and affects other properties. Intrinsic flame retardancy introduces flame retardant groups such as P, N, Si, etc. on the polyurethane main chain, which has high flame retardant efficiency and good migration resistance of the additives, so it has good development prospects. However, it is still very difficult to prepare halogen-free and environmentally friendly flame retardants with reactive groups and successfully introduce them into the polyurethane main chain. Summary of the invention
[0005] The purpose of the present invention is to provide a halogen-free reactive flame retardant, a halogen-free flame-retardant water-based polyurethane and a preparation method thereof. The flame retardant is in liquid form and has P and Si flame-retardant elements and active hydroxyl groups. While having excellent flame-retardant effects, it can also react with isocyanate (-NCO) in polyurethane prepolymers, thereby introducing P and Si flame-retardant elements into the polyurethane main chain through chemical bonds, thereby improving the flame retardant properties of the polyurethane.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is:
[0007] A halogen-free reactive flame retardant, the flame retardant is in liquid state, and its molecular structure is as follows:
[0008]
[0009] The preparation method of the above-mentioned halogen-free reactive flame retardant comprises the following steps:
[0010] S1. Under a nitrogen atmosphere, a platinum-based catalyst and 1,1,3,3-tetramethyldisiloxane are successively added to allyl glycidyl ether, and the mixture is heated to react after stirring. After the reaction is completed, TBDS is obtained by purification, elution, and vacuum concentration;
[0011] S2. Under a nitrogen atmosphere, TBDS, DOPO and triphenyl phosphate are mixed, heated and stirred, and cooled after the reaction is completed.
[0012] Preferably, the platinum-based catalyst is a Pt(0)-1,3-diethene-1,1,3,3-tetramethyldisiloxane complex solution, and the complex concentration is 1-5%;
[0013] The addition ratio of the platinum-based catalyst, allyl glycidyl ether and 1,1,3,3-tetramethyldisiloxane is (0.2-1) mL: (60-150) g: (40-80) g.
[0014] Preferably, a platinum-based catalyst and 1,1,3,3-tetramethyldisiloxane are added to allyl glycidyl ether at 0-5°C;
[0015] The conditions for the temperature reaction are: room temperature, stirring, 10-15h.
[0016] Preferably, the added mass ratio of TBDS to DOPO is (80-120):(70-145);
[0017] The amount of triphenyl phosphate added is 0.2-0.8% of the total mass of TBDS and DOPO.
[0018] Preferably, the heating and stirring conditions are: 130-165° C., 4-10 h.
[0019] A method for preparing a halogen-free flame-retardant waterborne polyurethane comprises the following steps: mixing an oligomer polyol and a hydrophilic chain extender under nitrogen protection, and then successively adding diisocyanate and the above-mentioned halogen-free reactive flame retardant under stirring to react, and then successively adding a neutralizer, deionized water and a chain extender and stirring.
[0020] Preferably, the added mass ratio of oligomer polyol, hydrophilic chain extender, diisocyanate, neutralizer, deionized water and chain extender is (70-150):(5-15):(30-60):(2-12):(170-300):(2-10);
[0021] The added amount of the halogen-free reactive flame retardant is 5-20% of the total mass of the oligomer polyol and the diisocyanate.
[0022] Preferably, the oligomer polyol is mixed with the hydrophilic chain extender and heated to 63-73°C; the diisocyanate is added and heated to 75-80°C and reacted for 0.5-1.5h; the halogen-free reactive flame retardant is added and reacted for 1.5-3h;
[0023] The reaction temperature was lowered to 55-65°C before adding the neutralizer, and stirred for 0.2-1h after adding the neutralizer;
[0024] The reaction temperature was lowered to 40-50°C before adding deionized water, and stirred at 800-1500 rpm for 0.5-2h after adding deionized water;
[0025] After adding the chain extender, stir for 2-5 hours.
[0026] Preferably, the oligomer polyol is a polyol that has been subjected to a dehydration treatment.
[0027] Preferably, the hydrophilic chain extender is 2,2-dimethylol propionic acid or 2,2-dimethylol butyric acid;
[0028] The diisocyanate is isophorone diisocyanate, xylylene diisocyanate or hexamethylene diisocyanate;
[0029] The neutralizing agent is triethylamine; the chain extender is ethylenediamine.
[0030] The beneficial effects of the present invention are:
[0031] 1. The prepared reactive halogen-free flame retardant TDP contains active hydroxyl groups (-OH), which can react with isocyanate (-NCO) in polyurethane prepolymers, thereby introducing P and Si flame retardant elements into the polyurethane main chain through chemical bonds;
[0032] 2. During the combustion process of polymers, flame retardant TDP is beneficial to promote the dehydration and carbonization of polyurethane, heat insulation and oxygen isolation, thereby improving the flame retardant properties of polyurethane;
[0033] 3. Reactive halogen-free flame retardant TDP is a low-viscosity liquid that can be added during the synthesis stage of polyurethane prepolymers. It has good compatibility with other raw materials, does not require the addition of organic solvents, and will not increase the viscosity of the system. It is conducive to the successful preparation of prepolymers and is safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 The synthetic route of 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS) in the embodiment is shown in FIG.
[0035] Figure 2 The synthetic route of the reactive halogen-free flame retardant bifunctional phosphaphenanthrene / siloxane molecule (TDP) in the embodiment;
[0036] Figure 3 The preparation route of the halogen-free flame-retardant waterborne polyurethane in the embodiment;
[0037] Figure 4 (a) SEM images of the surface morphology of the waterborne polyurethane strips prepared in Comparative Example 1 and Example 1 after combustion. DETAILED DESCRIPTION
[0038] In the following examples, the synthetic routes of 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS) and the reactive halogen-free flame retardant bifunctional phosphaphenanthrene / siloxane molecule (TDP) and the preparation route of halogen-free flame retardant waterborne polyurethane are shown in FIG. Figure 1 , 2 , as shown in Figure 3.
[0039] Embodiment 1:
[0040] (1) Preparation of halogen-free reactive flame retardant:
[0041] (a) Synthesis of bifunctional siloxane epoxy resin (TBDS):
[0042] Bifunctional siloxane epoxy resin 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS) was synthesized via hydrosilylation reaction.
[0043] In a nitrogen atmosphere, in a three-necked flask equipped with mechanical stirring, 0.2 mL of 2% platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane complex solution (Karsted catalyst, dissolved in xylene, Pt~2%) was added to 60 g of allyl glycidyl ether (AGE) at 0°C, and then 40 g of 1,1,3,3-tetramethyldisiloxane (TMDS) was slowly added dropwise to the above mixture. After stirring for 1 hour, the reaction mixture was warmed to room temperature and stirred for 12 hours. The reaction mixture was purified by dry column vacuum chromatography with silica gel as the stationary phase and n-heptane / ethyl acetate (volume ratio 4:1) as the eluent. Finally, the obtained product was concentrated under vacuum conditions by rotary evaporation to obtain a colorless oil TBDS.
[0044] (b) Synthesis of bifunctional phosphaphenanthrene / siloxane molecules (TDP):
[0045] In a nitrogen atmosphere, 80 g of 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS), 70 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 0.2% of triphenyl phosphate by mass were added to a three-necked round-bottom flask equipped with a mechanical stirrer. The mixture was heated to 150°C and stirred for 6 hours, and then cooled to room temperature to obtain a colorless oily substance, that is, a bifunctional phosphaphenanthrene / siloxane molecule (TDP).
[0046] (2) Preparation of halogen-free flame-retardant waterborne polyurethane resin:
[0047] First, polytetrahydrofuran diol (PTMEG, Mn = 2000g / mol) is subjected to reduced pressure dehydration at 120°C and -0.1MPa for 2 hours, 70g of the dehydrated polytetrahydrofuran diol and 5g of 2,2-dimethylol propionic acid are added to a four-necked flask with a thermometer, a condenser and a stirring paddle, and nitrogen is introduced for protection, and the temperature is raised to 70°C; then 30g of isophorone diisocyanate is slowly added dropwise under stirring, the temperature is raised to 75°C and stirred for reaction for 1 hour, 5g of halogen-free reactive flame retardant TDP is added and the reaction is continued for 2 hours, the reaction temperature is lowered to 60°C, 2g of neutralizing agent triethylamine is added and stirred for 30 minutes to obtain a waterborne polyurethane prepolymer, the temperature is further lowered to 45°C, and then 170g of deionized water is added for emulsification under strong mechanical stirring at 800rpm, and 2g of chain extender ethylenediamine is added and stirred for 3 hours to obtain a halogen-free flame-retardant waterborne polyurethane.
[0048] Embodiment 2:
[0049] (1) Preparation of halogen-free reactive flame retardant:
[0050] (a) Synthesis of bifunctional siloxane epoxy resin (TBDS):
[0051] Bifunctional siloxane epoxy resin 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS) was synthesized via hydrosilylation reaction.
[0052] In a nitrogen atmosphere, in a three-necked flask equipped with a mechanical stirrer, 0.5 mL of 2% platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane complex solution (Karsted catalyst, dissolved in xylene, Pt~2%) was added to 90 g of allyl glycidyl ether (AGE) at 0°C, and then 60 g of 1,1,3,3-tetramethyldisiloxane (TMDS) was slowly added dropwise to the above mixture. After stirring for 1 hour, the reaction mixture was warmed to room temperature and continued to stir for 12 hours. The reaction mixture was purified by dry column vacuum chromatography with silica gel as the stationary phase and n-heptane / ethyl acetate (volume ratio 4:1) as the eluent. Finally, the obtained product was concentrated under vacuum conditions by rotary evaporation to obtain a colorless oil TBDS.
[0053] (b) Synthesis of bifunctional phosphaphenanthrene / siloxane molecules (TDP):
[0054] In a nitrogen atmosphere, 100 g of 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS), 95 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 0.5% of triphenyl phosphate by mass were added to a three-necked round-bottom flask equipped with a mechanical stirrer. The mixture was heated to 150°C and stirred for 6 hours, and then cooled to room temperature to obtain a colorless oily substance, that is, a bifunctional phosphaphenanthrene / siloxane molecule (TDP).
[0055] (2) Preparation of halogen-free flame-retardant waterborne polyurethane resin:
[0056] First, polycarbonate diol (Mn=2000g / mol) was decompressed and dehydrated at 130°C and -0.1MPa for 2.5 hours, 100g of the dehydrated polycarbonate diol and 10g of a hydrophilic chain extender 2,2-dimethylol propionic acid were added to a four-necked flask with a thermometer, a condenser and a stirring paddle, and nitrogen was introduced for protection, and the temperature was raised to 70°C; then 45g of xylene diisocyanate was slowly added dropwise under stirring, the temperature was raised to 77°C and stirred for 1 hour, 15g of a halogen-free reactive flame retardant TDP was added and the reaction was continued for 2 hours, the reaction temperature was lowered to 60°C, 8g of a neutralizing agent triethylamine was added and stirred for 30 minutes to obtain a waterborne polyurethane prepolymer, the temperature was further lowered to 45°C, and then 220g of deionized water was added for emulsification under strong mechanical stirring at 1000rpm, and 6g of a chain extender ethylenediamine was added and stirred for 3 hours to obtain a halogen-free flame-retardant waterborne polyurethane.
[0057] Embodiment 3:
[0058] (1) Preparation of halogen-free reactive flame retardant:
[0059] (a) Synthesis of bifunctional siloxane epoxy resin (TBDS):
[0060] Bifunctional siloxane epoxy resin 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS) was synthesized via hydrosilylation reaction.
[0061] In a nitrogen atmosphere, in a three-necked flask equipped with a mechanical stirrer, 1.0 mL of 2% platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane complex solution (Karsted catalyst, dissolved in xylene, Pt~2%) was added to 150 g of allyl glycidyl ether (AGE) at 0°C, and then 80 g of 1,1,3,3-tetramethyldisiloxane (TMDS) was slowly added dropwise to the above mixture. After stirring for 1 hour, the reaction mixture was warmed to room temperature and continued to stir for 12 hours. The reaction mixture was purified by dry column vacuum chromatography with silica gel as the stationary phase and n-heptane / ethyl acetate (volume ratio 4:1) as the eluent. Finally, the obtained product was concentrated under vacuum conditions by rotary evaporation to obtain a colorless oil TBDS.
[0062] (b) Synthesis of bifunctional phosphaphenanthrene / siloxane molecules (TDP):
[0063] In a nitrogen atmosphere, 120 g of 1,1,3,3-tetramethyl-1,3-bis[3-(oxiranylmethoxy)propyl]disiloxane (TBDS), 145 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 0.8% of triphenyl phosphate by mass were added to a three-necked round-bottom flask equipped with a mechanical stirrer. The mixture was heated to 150°C and stirred for 6 hours, and then cooled to room temperature to obtain a colorless oily substance, that is, a bifunctional phosphaphenanthrene / siloxane molecule (TDP).
[0064] (2) Preparation of halogen-free flame-retardant waterborne polyurethane resin:
[0065] First, polycaprolactone diol (Mn=2000g / mol) was decompressed and dehydrated at 150°C and -0.1MPa for 3 hours, 150g of the dehydrated polycaprolactone diol and 15g of a hydrophilic chain extender 2,2-dihydroxymethylbutyric acid were added to a four-necked flask with a thermometer, a condenser and a stirring paddle, and nitrogen was introduced for protection, and the temperature was raised to 70°C; then 60g of hexamethylene diisocyanate was slowly added dropwise under stirring, the temperature was raised to 80°C and stirred for 1 hour, 42g of a halogen-free reactive flame retardant TDP was added and the reaction was continued for 2 hours, the reaction temperature was lowered to 60°C, 12g of a neutralizing agent triethylamine was added and stirred for 30 minutes to obtain a waterborne polyurethane prepolymer, the temperature was further lowered to 45°C, and then 300g of deionized water was added for emulsification under strong mechanical stirring at 1500rpm, and 10g of a chain extender ethylenediamine was added and stirred for 3 hours to obtain a halogen-free flame-retardant waterborne polyurethane.
[0066] Comparative Example 1:
[0067] Preparation of waterborne polyurethane resin:
[0068] First, polytetrahydrofuran diol (PTMEG, Mn = 2000g / mol) is subjected to reduced pressure dehydration at 120°C and -0.1MPa for 2 hours, 70g of the dehydrated polytetrahydrofuran diol and 5g of 2,2-dimethylol propionic acid are added to a four-necked flask with a thermometer, a condenser and a stirring paddle, and nitrogen is introduced for protection, and the temperature is raised to 70°C; then 30g of isophorone diisocyanate is slowly added dropwise under stirring, the temperature is raised to 75°C and stirred for reaction for 1 hour, the reaction temperature is lowered to 60°C, 2g of a neutralizing agent triethylamine is added and stirred for 30 minutes to obtain a waterborne polyurethane prepolymer, the temperature is further lowered to 45°C, and then 170g of deionized water is added under strong mechanical stirring at 800rpm for emulsification, and 2g of a chain extender ethylenediamine is added and stirred for 3 hours to obtain a waterborne polyurethane resin.
[0069] Table 1 shows the oxygen index of the waterborne polyurethane strips of Comparative Example 1 and Example 1, Example, and Example 3. According to the classification of combustion levels of substances in GB / T2406.2-2009 / ISO4589-2:1996, the waterborne polyurethane of Comparative Example 1 is a flammable material, while the waterborne polyurethanes prepared in Example 1, Example 2, and Example 3 have a higher oxygen index due to the introduction of flame retardant groups, reaching the level of flame retardant materials.
[0070] Table 1
[0071] sample Comparative Example 1 Example 1 Example 2 Example 3 Oxygen index (%) 17.9 27.3 27.7 28.1
[0072] Figure 4Area a in the middle is the surface morphology of the residual carbon after the water-based polyurethane sample prepared in Comparative Example 1 is burned. It can be seen from the figure that the surface structure of the residual carbon after the water-based polyurethane is burned is relatively loose and has a large number of voids. This carbon layer structure is not sufficient to isolate the external heat from being transferred into the interior of the polymer, nor is it sufficient to isolate oxygen to delay combustion. Therefore, the water-based polyurethane sample prepared in Comparative Example 1 is flammable. Figure 4 The middle b area is the surface morphology of the residual carbon after the combustion of the halogen-free flame-retardant waterborne polyurethane sample prepared in Example 1. It can be seen that the carbon layer on the surface of the sample after adding the flame retardant is denser. The addition of the flame retardant can promote the carbonization reaction and form a dense carbon layer, which effectively insulates heat and blocks oxygen, fundamentally delaying combustion and achieving flame retardancy.
[0073] The above is only a preferred implementation of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.
Claims
1. A halogen-free reactive flame retardant, characterized in that: The flame retardant is in liquid state, and its molecular structure is as follows:
2. The method for preparing the halogen-free reactive flame retardant according to claim 1, characterized in that: The steps include: S1. Under a nitrogen atmosphere, a platinum-based catalyst and 1,1,3,3-tetramethyldisiloxane are successively added to allyl glycidyl ether, and the mixture is heated to react after stirring. After the reaction is completed, TBDS is obtained by purification, elution, and vacuum concentration; S2. Under a nitrogen atmosphere, TBDS, DOPO and triphenyl phosphate are mixed, heated and stirred, and cooled after the reaction is completed.
3. The method for preparing a halogen-free reactive flame retardant according to claim 2, characterized in that: The platinum-based catalyst is a Pt(0)-1,3-diethene-1,1,3,3-tetramethyldisiloxane complex solution, and the complex concentration is 1-5%; The addition ratio of the platinum-based catalyst, allyl glycidyl ether and 1,1,3,3-tetramethyldisiloxane is (0.2-1) mL: (60-150) g: (40-80) g.
4. The method for preparing a halogen-free reactive flame retardant according to claim 2, characterized in that: Adding a platinum-based catalyst and 1,1,3,3-tetramethyldisiloxane to allyl glycidyl ether at 0-5°C; The conditions for the temperature reaction are: room temperature, stirring, 10-15h.
5. The method for preparing a halogen-free reactive flame retardant according to claim 2, characterized in that: The added mass ratio of TBDS to DOPO is (80-120):(70-145); The amount of triphenyl phosphate added is 0.2-0.8% of the total mass of TBDS and DOPO.
6. The method for preparing a halogen-free reactive flame retardant according to claim 2, characterized in that: The heating and stirring conditions are: 130-165°C, 4-10h.
7. A method for preparing a halogen-free flame-retardant waterborne polyurethane, characterized in that: The method comprises mixing oligomer polyol and hydrophilic chain extender under nitrogen protection, and then adding diisocyanate and the halogen-free reactive flame retardant according to claim 1 in succession to react under stirring, and then adding neutralizer, deionized water and chain extender in succession to stir.
8. The method for preparing the halogen-free flame-retardant waterborne polyurethane according to claim 7, characterized in that: The added mass ratio of oligomer polyol, hydrophilic chain extender, diisocyanate, neutralizer, deionized water and chain extender is (70-150):(5-15):(30-60):(2-12):(170-300):(2-10); The added amount of the halogen-free reactive flame retardant is 5-20% of the total mass of the oligomer polyol and the diisocyanate.
9. The method for preparing the halogen-free flame-retardant waterborne polyurethane according to claim 7, characterized in that: After mixing the oligomer polyol and the hydrophilic chain extender, the temperature is raised to 63-73°C; after adding the diisocyanate, the temperature is raised to 75-80°C and reacted for 0.5-1.5h; The halogen-free reactive flame retardant reacts for 1.5-3 hours after being added; The reaction temperature was lowered to 55-65°C before adding the neutralizer, and stirred for 0.2-1h after adding the neutralizer; The reaction temperature was lowered to 40-50°C before adding deionized water, and stirred at 800-1500 rpm for 0.5-2h after adding deionized water; After adding the chain extender, stir for 2-5 hours.
10. The method for preparing the halogen-free flame-retardant waterborne polyurethane according to claim 8, characterized in that: The oligomer polyol is a polyol after dehydration treatment; The hydrophilic chain extender is 2,2-dimethylol propionic acid or 2,2-dimethylol butyric acid; The diisocyanate is isophorone diisocyanate, xylylene diisocyanate or hexamethylene diisocyanate; The neutralizing agent is triethylamine; The chain extender is ethylenediamine.