Flame-retardant autocatalytic soft-polyurethane polyol, its preparation method and application

Abstract

The present application belongs to the technical field of polyether polyol preparation, and particularly relates to a flame-retardant self-catalytic soft bubble polyether polyol, a preparation method thereof and application. The flame-retardant self-catalytic soft bubble polyether polyol is obtained by two-stage polymerization reaction of polyether amine, polyol and bromine-containing flame-retardant auxiliary as a composite initiator under the action of a catalyst and alkylene oxide. The flame-retardant self-catalytic soft bubble polyether polyol provided by the present application uses polyether amine as a main initiator, and is compounded with polyol containing active hydrogen and reactive flame-retardant monomer, and has self-catalytic activity and reactive flame-retardant double functions, and is applied to the preparation of soft polyurethane sponge, can reduce the use amount of exogenous amine catalyst and flame retardant, significantly reduces the volatility of the product, and has durable flame-retardant performance, no precipitation and migration phenomenon, and the prepared product has excellent mechanical properties. The present application also provides a preparation method of the polyether polyol.

Description

Technical Field

[0001] This invention belongs to the field of polyether polyol preparation technology, specifically relating to a flame-retardant self-catalytic flexible foam polyether polyol, its preparation method, and its application. Background Technology

[0002] Polyurethane materials occupy an important position in the field of polymer materials due to their properties such as oil resistance, aging resistance, wear resistance, water resistance, heat and sound insulation, and excellent elasticity. In particular, flexible polyurethane foam materials, with their high resilience, low density, strong comfort, and excellent mechanical properties, are widely used in furniture, automotive interiors, high-speed rail seats, home textiles, and high-end cushioning materials. However, there are two major problems in the traditional flexible foam preparation process: First, foaming requires the addition of a large amount of small-molecule tertiary amine catalysts. These small molecules are prone to migration and volatility, resulting in strong odors, excessive VOCs, and problems such as fogging of automotive windows and indoor air pollution, severely limiting its application in high-end fields. Second, flexible foam itself is flammable, usually requiring the addition of liquid flame retardants. However, these added flame retardants are prone to precipitation, migration, and oil seepage, which not only reduces the mechanical properties and service life of the foam but also further exacerbates odor and volatility problems, making it difficult to meet flame retardant requirements.

[0003] Currently, CN111410738A discloses a method for preparing amine-based self-catalytic polyether polyols. The method uses a complex initiator composed of polyamines, diols, and high-functionality polyols. An alkali metal aqueous solution is used as a catalyst, and the polyether undergoes ring-opening polymerization with propylene oxide and ethylene oxide in two stages. First, an oligomer intermediate is synthesized, followed by chain extension and end-capping. After purification, a self-catalytic polyether with a number average molecular weight of 1000-8000 is obtained. This self-catalytic function is achieved by introducing tertiary amine groups into the polyether molecule, which can significantly reduce the amount of small-molecule amine catalyst used during polyurethane flexible foam foaming, and significantly reduce VOC emissions and odor. However, this polyether polyol does not contain a flame-retardant structure and still requires the addition of external flame retardants, posing a risk of flame-retardant component migration. Therefore, it cannot comprehensively solve the problems of low odor and permanent flame retardancy.

[0004] CN110078885A discloses a composite polyether polyol with flame retardant and autocatalytic properties and its applications. It is composed of conventional polyether, polymer polyol, and modified polyether grafted with melamine and special amine compounds. The amount of organic amine catalyst can be reduced to 0-0.3 parts. It grafts amines and melamine onto the polyether backbone through in-situ polymerization, achieving both autocatalytic and flame retardant effects. It can reduce VOC emissions, improve the flame retardancy and dimensional stability of foam, and produce products with low odor and fine cell structure. However, this method relies on a multi-component compounding approach. Although it can achieve the stability of polyurethane products, the process is complex, the product compatibility and batch stability are poor, and the flame retardant efficiency is low.

[0005] CN110698661A discloses a reactive flame-retardant polyether polyol and its preparation method. Using tetrabromophthalic anhydride and tetrabromobisphenol A as initiators, it undergoes two-stage polymerization with propylene oxide / ethylene oxide under alkaline catalysis. After curing, a halogen-containing flame-retardant polyether is obtained. It employs a bromine-based reactive flame-retardant design, with flame-retardant elements integrated into the molecular chain to achieve flame retardancy. When used in the preparation of polyurethane foam, it exhibits high strength, good dimensional stability, low thermal conductivity, strong adhesion, and flame retardancy. However, it only achieves flame retardant function and lacks autocatalytic function, still requiring the addition of a large amount of small molecule amine catalyst. VOC and odor issues are not improved, failing to meet the requirements for high-end, low-fogging applications.

[0006] In summary, while existing technologies have conducted extensive research on the application of autocatalytic polyethers and flame-retardant polyethers in polyurethane foam, they mostly employ combined polyether approaches or require the addition of additional flame retardants. It is difficult to simultaneously achieve autocatalysis and reactive flame retardancy within the molecular structure of a single polyether polyol. Therefore, designing an autocatalytic flame-retardant polyether for direct application in the polyurethane foam field, without the need for additional flame retardants or compounding with other polyethers, while simultaneously satisfying comprehensive properties such as low odor, low VOC, autocatalytic foaming, permanent flame retardancy, and high resilience, is of great significance. Summary of the Invention

[0007] To overcome the aforementioned deficiencies in the prior art, this invention provides a flame-retardant self-catalytic flexible foam polyether polyol. Using polyether amine as the main initiator, it is compounded with a polyol containing active hydrogen and a brominated reactive flame-retardant monomer. This polyol possesses both self-catalytic activity and reactive flame-retardant properties. When applied to the preparation of flexible polyurethane foam, it can reduce the amount of exogenous amine catalyst and flame retardant used, significantly reduce the volatility of the product, and provide long-lasting flame retardant performance without precipitation or migration. The resulting product exhibits excellent mechanical properties. This invention also provides a method for preparing this polyether polyol.

[0008] The flame-retardant self-catalytic flexible foam polyether polyol of the present invention is obtained by a two-stage polymerization reaction of polyether amine, polyol and bromine-containing flame retardant additive as composite initiators and epoxy alkane under the action of a catalyst; wherein, the polyether amine has a functionality of 2-4, a number average molecular weight of 200-500 g / mol, and a total amine value of 200-500 mg KOH / g, and the bromine-containing flame retardant additive is one of tetrabromobisphenol A, tetrabromobisphenol F and dibromoneopentyl glycol.

[0009] Preferably, the polyetheramine is one of ZD-123, ZT-143, and ZD-2410.

[0010] The polyol is one of glycerol, propylene glycol, diethylene glycol, ethylene glycol, sorbitol, pentaerythritol, xylitol, mannitol, sucrose, and glucoside, with pentaerythritol, glycerol, and ethylene glycol being preferred polyols.

[0011] The epoxide is one or more of ethylene oxide, propylene oxide, and butane oxide.

[0012] In the two-stage polymerization reaction, the alkyl oxide in the first stage polymerization reaction is one or two of propylene oxide and butyl oxide; in the second stage polymerization reaction, the alkyl oxide is a mixture of ethylene oxide and one or two of propylene oxide and butyl oxide, with ethylene oxide accounting for 10-20% of the total mass of the mixture.

[0013] The catalyst is one or more of sodium hydroxide, potassium hydroxide, dimethylamine, and potassium methoxide.

[0014] The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol of the present invention includes the following steps: (1) Add polyetheramine, polyol, bromine-containing flame retardant and catalyst to the reactor, and perform nitrogen replacement and vacuum dehydration. Then introduce epoxy alkane, control the reaction temperature to 100-120℃ and the reaction pressure to 0.2-0.4MPa, and carry out internal pressure reaction for 2-6h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol; (2) The intermediate polyether polyol and the catalyst are put into the reactor and subjected to nitrogen replacement and vacuum dehydration. Epoxy alkane is introduced and the reaction temperature is controlled at 100-120℃ and the reaction pressure is 0.1-0.3MPa. The internal pressure reaction is carried out for 3-6 hours. After the second stage of polymerization is completed, the unreacted monomers are removed by vacuum and the flame-retardant self-catalytic flexible foam polyether polyol is obtained after post-treatment.

[0015] In step (1), the mass ratio of polyetheramine, polyol and bromine-containing flame retardant is (6.5-10.0):(0.75-1.2):1.

[0016] In step (1), the mass ratio of epoxide to composite initiator is (2.5-5.5):1; in step (2), the mass ratio of epoxide to intermediate polyether polyol is (1.5-3):1; in both steps (1) and (2), the amount of catalyst used is 0.1-0.4% of the total mass of raw materials in the corresponding steps.

[0017] In step (2), the specific post-processing process is as follows: add pure water and adsorbent to the reaction vessel, stir and adsorb for 2-4 hours to obtain flame-retardant self-catalytic flexible foam polyether polyol; wherein, the adsorbent is one of magnesium silicate, aluminum silicate, and magnesium aluminum silicate, and the amount used is 0.5-2.5% of the total mass of the raw materials; the amount of pure water used is 1-5% of the total mass of the raw materials.

[0018] The flame-retardant self-catalytic flexible foam polyether polyol is used in the preparation of flexible polyurethane foam.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The flame-retardant self-catalytic flexible foam polyether polyol of the present invention uses polyether amine as the main initiator, and combines active hydrogen polyol with bromine reactive flame-retardant monomer. The polyether prepared has amine catalytic activity and covalently bonded bromine flame-retardant structure, which can greatly reduce the use of exogenous amine catalysts and additive flame retardants.

[0020] (2) The flame-retardant self-catalytic flexible foam polyether polyol of the present invention has flame-retardant groups attached to the polyether molecular chain through chemical bonds. Unlike traditional physical blending or post-addition reactive flame retardants, it will not migrate or precipitate. The flame-retardant effect will not decrease with long-term use. When applied to flexible polyurethane foam, the flame-retardant performance is stable for a long time and no other polyethers need to be added. The product has excellent mechanical properties and a wide range of applications.

[0021] (3) The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol of the present invention adopts two-stage polymerization, the polymerization process is highly controllable, the product has good stability and moderate viscosity. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the embodiments and comparative examples. Unless otherwise specified, the raw materials used in the embodiments and comparative examples are all conventional commercial raw materials, and the process methods used are all conventional methods in the art unless otherwise specified.

[0023] The raw materials for the examples and comparative examples are described below: Polyetheramine ZD-123: Functionality 2, number-average molecular weight 230 g / mol, total amine value 482 mg KOH / g, Zibo Zhengda Polyurethane Co., Ltd. Polyetheramine ZT-143: Functionality 3, number-average molecular weight 440 g / mol, total amine value 365 mg KOH / g, Zibo Zhengda Polyurethane Co., Ltd. Polyetheramine ZD-2410: Functionality 2, number-average molecular weight 500 g / mol, total amine value 246 mg KOH / g, Zibo Zhengda Polyurethane Co., Ltd. Polyether polyol 560D: DEP-560D, Zibo Dexin Federal Chemical Industry Co., Ltd.

[0024] Example 1 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 240g of polyetheramine ZT-143, 30.0g of pentaerythritol and 25.0g of tetrabromobisphenol A to the reactor and replace it with nitrogen. Dehydrate under vacuum at 110±5℃ for 2h. Then introduce 5.1g of dimethylamine and 1400g of propylene oxide. Control the reaction temperature at 110±10℃ and the reaction pressure at 0.3MPa. Perform internal pressure reaction for 4h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol with a hydroxyl value of 140mgKOH / g. (2) 800g of intermediate polyether polyol and 2.2g of NaOH were added to the reactor. After nitrogen purging, the mixture was vacuum dehydrated at 110±5℃ for 2h. 1200g of a mixture of propylene oxide and ethylene oxide (PO to EO mass ratio of 85:15) was introduced. The reaction temperature was controlled at 110±10℃ and the reaction pressure at 0.1MPa. The reaction was carried out under internal pressure for 5h. After the second stage of polymerization was completed, the unreacted monomers were removed under vacuum. 95g of pure water and 50g of magnesium silicate were added and stirred for 2h for adsorption. Then, the mixture was vacuum dehydrated at 120℃ for 4h and filtered to obtain flame-retardant self-catalytic flexible foam polyether polyol.

[0025] Example 2 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 240g of polyetheramine ZD-123, 30.0g of glycerol, 35.0g of tetrabromobisphenol F and 2.1g of KOH to the reactor and perform nitrogen purging. Dehydrate under vacuum at 110±5℃ for 2h. Then introduce 1630g of a mixture of propylene oxide and butylene oxide (PO:BO mass ratio of 1:1). Control the reaction temperature at 110±10℃ and the reaction pressure at 0.2MPa. Perform internal pressure reaction for 6h. After the first stage of polymerization is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol with a hydroxyl value of 155mgKOH / g. (2) 400g of intermediate polyether polyol and 4.8g of KOH were added to the reactor. After nitrogen purging, the mixture was vacuum dehydrated at 110±5℃ for 2h. 1200g of a mixture of epoxide butane and ethylene oxide (BO:EO mass ratio of 90:10) was introduced. The reaction temperature was controlled at 100±5℃ and the reaction pressure at 0.3MPa. The reaction was carried out under internal pressure for 4h. After the second stage of polymerization was completed, the unreacted monomers were removed under vacuum. 40g of pure water and 24.5g of magnesium silicate were added and stirred for adsorption for 3h. Then, the mixture was vacuum dehydrated at 120℃ for 4h and filtered to obtain flame-retardant self-catalytic flexible foam polyether polyol.

[0026] Example 3 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 240g of polyetheramine ZD-2410, 30.0g of ethylene glycol, 25.0g of tetrabromobisphenol A and 4.3g of potassium methoxide to the reactor and perform nitrogen purging. Dehydrate under vacuum at 110±5℃ for 2h. Then introduce 800g of a mixture of propylene oxide and butyl oxide (PO:BO mass ratio of 1:1), control the reaction temperature at 110±10℃ and the reaction pressure at 0.4MPa, and perform internal pressure reaction for 2h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol with a hydroxyl value of 160mgKOH / g. (2) 400g of intermediate polyether polyol and 2.5g of potassium methoxide were added to the reactor. After nitrogen purging, the mixture was vacuum dehydrated at 110±5℃ for 2h. 900g of a mixture of propylene oxide, butane oxide and ethylene oxide (PO:BO:EO mass ratio of 46:46:18) was introduced. The reaction temperature was controlled at 110±10℃ and the reaction pressure at 0.2MPa. The reaction was carried out under internal pressure for 3h. After the second stage of polymerization was completed, the unreacted monomers were removed under vacuum. 14g of pure water and 6.5g of magnesium silicate were added and stirred for adsorption for 4h. Then, the mixture was vacuum dehydrated at 120℃ for 4h and filtered to obtain flame-retardant self-catalytic flexible foam polyether polyol.

[0027] Example 4 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 280g of polyetheramine ZD-123, 30.0g of glycerol, 40.0g of dibromoneopentyl glycol and 4.2g of KOH to the reactor and perform nitrogen purging. Dehydrate under vacuum at 110±5℃ for 2h. Then introduce 1630g of a mixture of propylene oxide and butyl oxide (PO:BO mass ratio of 1:1). Control the reaction temperature at 105±5℃ and the reaction pressure at 0.3MPa and perform internal pressure reaction for 5h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol with a hydroxyl value of 171mgKOH / g. (2) 800g of intermediate polyether polyol and 5.5g of NaOH were added to the reactor. After nitrogen purging, the mixture was vacuum dehydrated at 110±5℃ for 2h. 1500g of a mixture of propylene oxide, butane oxide and ethylene oxide (PO:BO:EO mass ratio of 45:35:20) was introduced. The reaction temperature was controlled at 110±10℃ and the reaction pressure at 0.2MPa. The reaction was carried out under internal pressure for 6h. After the second stage of polymerization was completed, the unreacted monomers were removed by vacuum. 110g of pure water and 48g of a mixture of magnesium silicate / alumina silicate = 1 / 1 were added. The mixture was stirred and adsorbed for 2.5h. Then, the mixture was vacuum dehydrated at 120℃ for 4h. After filtration, flame-retardant self-catalytic flexible foam polyether polyol was obtained.

[0028] Comparative Example 1 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 80g of triethylenetetramine, 30.0g of pentaerythritol and 25.0g of tetrabromobisphenol A to the reactor, replace with nitrogen, dehydrate under vacuum at 110±5℃ for 2h, then introduce 5.1g of dimethylamine and 1400g of propylene oxide, control the reaction temperature at 110±10℃ and the reaction pressure at 0.3MPa, and carry out internal pressure reaction for 4h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol; (2) 800g of intermediate polyether polyol and 2.2g of NaOH were added to the reactor. After nitrogen purging, the mixture was vacuum dehydrated at 110±5℃ for 2h. 1280g of a mixture of propylene oxide and ethylene oxide (PO:EO mass ratio of 85:15) was introduced. The reaction temperature was controlled at 110±10℃ and the reaction pressure at 0.3MPa. The reaction was carried out under internal pressure for 5h. After the second stage of polymerization was completed, the unreacted monomers were removed under vacuum. 38g of pure water and 26g of magnesium silicate were added and stirred for adsorption for 4h. Then, the mixture was vacuum dehydrated at 120℃ for 4h and filtered to obtain flame-retardant self-catalytic flexible foam polyether polyol.

[0029] Comparative Example 2 The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 240g ZT to the reactor 143 g pentaerythritol, 30.0 g tetrabromobisphenol A, and 9.2 g KOH were purged with nitrogen and dehydrated under vacuum at 110 ± 5 °C for 2 h. Then, 1400 g PO + 4850 g PO / EO (85:15) mixed epoxy alkane was introduced. The reaction temperature was controlled at 110 ± 10 °C and the reaction pressure at 0.3 MPa for 10 h under internal pressure. After the reaction was completed, unreacted monomers were removed under vacuum. 95 g pure water and 50 g magnesium silicate were added and stirred for 2 h for adsorption. Then, the mixture was dehydrated under vacuum at 120 °C for 4 h and filtered to obtain flame-retardant self-catalytic flexible foam polyether polyol.

[0030] Comparative Example 3 The preparation method of the self-catalytic flexible foam polyether polyol includes the following steps: (1) Add 240g ZT to the reactor 143 g pentaerythritol and 4.3 g KOH were purged with nitrogen and dehydrated under vacuum at 110±5 °C for 2 h. Then 1400 g propylene oxide was introduced and the reaction temperature was controlled at 110±10 °C and the reaction pressure at 0.3 MPa for 4 h under internal pressure. After the first stage of polymerization was completed, unreacted monomers were removed under vacuum to obtain intermediate polyether polyol. (2) 800g of intermediate polyether polyol and 2.2g of NaOH were added to the reactor and nitrogen was replaced. The mixture was vacuum dehydrated at 110±5℃ for 2h. 1400g of a mixture of propylene oxide and ethylene oxide (PO:EO mass ratio of 85:15) was introduced. The reaction temperature was controlled at 110±10℃ and the reaction pressure was 0.3MPa. The reaction was carried out under internal pressure for 6h. After the second stage of polymerization was completed, the unreacted monomers were removed by vacuum. 95g of pure water and 50g of magnesium silicate were added and stirred for 2h for adsorption. Then, the mixture was vacuum dehydrated at 120℃ for 4h and filtered to obtain the self-catalytic flexible foam polyether polyol.

[0031] In this comparative example, tetrabromobisphenol A was added externally as a reactive flame retardant during use, and the amount was 3.2% of the mass of the polyether polyol.

[0032] Comparative Example 4 The flame-retardant self-catalytic flexible foam polyether polyol was prepared by replacing the commercially available polyether polyol 560D with a conventional commercially available additive bromine-based flame retardant, decabromodiphenyl ether, at a dosage of 3.2% of the polyether polyol mass. The mixture was stirred and set aside.

[0033] The relevant parameters of the products obtained in the examples and comparative examples are shown in Table 1 below.

[0034] Table 1. Product Parameters for Examples and Comparative Examples

[0035] The products prepared in the above examples and comparative examples were applied to the preparation of soft polyurethane foam. The formulation described in Table 2 was used as component A, and combined with component B, isocyanate (WANNATE from Wanhua Chemical Group Co., Ltd.). ® Soft polyurethane foam was prepared by mixing TDI-65 at a mass ratio of 100:48.

[0036] Table 2 Formulation of Component A in Examples and Comparative Samples

[0037] The resulting soft polyurethane foam underwent performance testing. The foam release time was recorded when components A and B were mixed. Product density was tested according to standard GB / T6343-2021, resilience was tested according to standard GB / T6670-2008, indentation hardness was tested according to standard GB / T10807-2021, odor level was tested according to standard GB / T10802-2023, and limiting oxygen index was tested according to standard GB / T2406.2. Tested in 2021, VOC reference standard VDA278, tensile strength reference GB / T6344-2008, tear strength according to standard GB / T10808-2006, dynamic fatigue test reference standard GB / T10802-2023, and the test results after 100h treatment at 40℃ / 93%RH after damp heat aging. All performance test results are shown in Table 3.

[0038] Table 3. Performance test results of flexible polyurethane foam

[0039] As shown in Tables 1-3, compared with Example 1, Comparative Example 1 uses small-molecule triethylenetetramine to replace polyetheramine. The small-molecule amine has excessively high reactivity and a fast reaction rate, which leads to uncontrolled chain growth, disordered molecular chain arrangement, significantly widened molecular weight distribution, increased system viscosity, and difficulty in forming a uniform and dense cross-linked network. At the same time, the excessive reaction of amine groups causes a decrease in the utilization rate of effective catalytic sites, reduces foaming catalytic efficiency, and significantly prolongs the foaming time. Due to the influence of the reaction rate, the phenolic hydroxyl groups of tetrabromobisphenol A cannot be stably integrated into the main chain, and the flame-retardant structure cannot effectively participate in cross-linking, further weakening the support strength of the polyurethane skeleton, ultimately resulting in a comprehensive deterioration in mechanical properties such as tensile strength and tear strength.

[0040] Compared with Example 1, the one-time addition of epoxides in Comparative Example 2 resulted in simultaneous chain growth and end-capping reactions, uncontrollable molecular chain structure, significantly wider molecular weight distribution, increased polyether viscosity and uneven distribution of active groups, and decreased autocatalytic efficiency and flame retardant group utilization. The resulting foam crosslinking network lacked regularity, and its resilience, indentation hardness, tensile strength and tear strength were all lower than those in Example 1. Incomplete conversion of the reactants led to increased odor and VOC levels, weak bonding of the bromine-based flame retardant structure, and a more significant decrease in oxygen index after humid heat aging, resulting in slight collapse during dynamic fatigue.

[0041] Compared with Example 1, Comparative Example 3 did not introduce tetrabromobisphenol A as an initiator into the polyether molecular chain. Instead, tetrabromobisphenol A was added externally as a reactive flame retardant only during the foaming stage. Although it could be integrated into the polyurethane crosslinking network, the dispersion uniformity of the flame retardant units and the polyether backbone was significantly reduced, which easily caused local crosslinking defects. At the same time, the added flame retardant could not participate in the construction of polyether segments simultaneously, resulting in a decrease in foam indentation hardness, tensile and tear strength, and obvious collapse during dynamic fatigue. Furthermore, the unevenly dispersed flame retardant units were more prone to inter-chain migration under humid and hot conditions, and the oxygen index decreased significantly after humid and hot aging.

[0042] Compared with Example 1, Comparative Example 4 uses a commercially available polyether polyol with an added brominated flame retardant. It lacks a self-catalytic structure and a reactive flame retardant structure, relying entirely on the added small molecule amine catalyst and the added flame retardant. The amount of exogenous catalyst is greatly increased, resulting in the highest odor level and the largest VOC release. The added flame retardant and polyether are only physically blended, resulting in poor system compatibility and an incomplete crosslinking network. The foam's compressive hardness, resilience, mechanical strength, and dynamic fatigue performance are all significantly worse.

[0043] In summary, this invention uses polyetheramine, polyol, and reactive brominated flame retardant as composite initiators to produce a self-catalytically flame-retardant integrated flexible foam polyether polyol through two-stage polymerization. This polyol exhibits a narrow molecular weight distribution, moderate viscosity, and no migration or precipitation of the covalently bonded flame-retardant structure. The resulting foam demonstrates high resilience, excellent indentation hardness, high tensile and tear strength, and does not collapse after 80,000 dynamic fatigue cycles. It also has an initial oxygen index ≥27.2% and maintains excellent flame-retardant properties even after damp heat aging. The A-33 dosage is only 0.2g, with an odor rating of 3.0-3.5 and low VOCs.

Claims

1. A flame-retardant, self-catalytic flexible foam polyether polyol, characterized in that, The product is obtained by two-stage polymerization of polyetheramine, polyol and bromine-containing flame retardant additive with epoxide under the action of catalyst. The polyetheramine has a functionality of 2-4, a number-average molecular weight of 200-500 g / mol, and a total amine value of 200-500 mg KOH / g; The bromine-containing flame retardant is one of tetrabromobisphenol A, tetrabromobisphenol F, and dibromoneopentyl glycol.

2. The flame-retardant self-catalytic flexible foam polyether polyol according to claim 1, characterized in that, The polyol is one of glycerol, propylene glycol, diethylene glycol, ethylene glycol, sorbitol, pentaerythritol, xylitol, mannitol, sucrose, and glucoside.

3. The flame-retardant self-catalytic flexible foam polyether polyol according to claim 1, characterized in that, The epoxide is one or more of ethylene oxide, propylene oxide, and butane oxide.

4. The flame-retardant self-catalytic flexible foam polyether polyol according to claim 1, characterized in that, In the two-stage polymerization reaction, the alkyl oxide in the first stage polymerization reaction is one or two of propylene oxide and butyl oxide; in the second stage polymerization reaction, the alkyl oxide is a mixture of ethylene oxide and one or two of propylene oxide and butyl oxide, with ethylene oxide accounting for 10-20% of the total mass of the mixture.

5. The flame-retardant self-catalytic flexible foam polyether polyol according to claim 1, characterized in that, The catalyst is one or more of sodium hydroxide, potassium hydroxide, dimethylamine, and potassium methoxide.

6. A method for preparing the flame-retardant self-catalytic flexible foam polyether polyol according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Add polyetheramine, polyol, bromine-containing flame retardant and catalyst to the reactor, and perform nitrogen replacement and vacuum dehydration. Then introduce epoxy alkane, control the reaction temperature to 100-120℃ and the reaction pressure to 0.2-0.4MPa, and carry out internal pressure reaction for 2-6h. After the first stage of polymerization reaction is completed, remove unreacted monomers under vacuum to obtain intermediate polyether polyol; (2) The intermediate polyether polyol and the catalyst are put into the reactor and subjected to nitrogen replacement and vacuum dehydration. Epoxy alkane is introduced and the reaction temperature is controlled at 100-120℃ and the reaction pressure is 0.1-0.3MPa. The internal pressure reaction is carried out for 3-6 hours. After the second stage of polymerization is completed, the unreacted monomers are removed by vacuum and the flame-retardant self-catalytic flexible foam polyether polyol is obtained after post-treatment.

7. The preparation method of the flame-retardant self-catalytic flexible foam polyether polyol according to claim 6, characterized in that, In step (1), the mass ratio of polyetheramine, polyol and bromine-containing flame retardant is (6.5-10.0):(0.75-1.2):

1.

8. The method for preparing the flame-retardant self-catalytic flexible foam polyether polyol according to claim 6, characterized in that, In step (1), the mass ratio of epoxide to composite initiator is (2.5-5.5):1; in step (2), the mass ratio of epoxide to intermediate polyether polyol is (1.5-3):1; in steps (1) and (2), the amount of catalyst used is 0.1-0.4% of the total mass of raw materials in the corresponding steps.

9. The method for preparing the flame-retardant self-catalytic flexible foam polyether polyol according to claim 6, characterized in that, In step (2), the specific post-processing process is as follows: add pure water and adsorbent to the reaction vessel, stir and adsorb for 2-4 hours to obtain flame-retardant self-catalytic flexible foam polyether polyol; wherein, the adsorbent is one of magnesium silicate, aluminum silicate, and magnesium aluminum silicate, and the amount used is 0.5-2.5% of the total mass of the reaction raw materials; the amount of pure water used is 1-5% of the total mass of the reaction raw materials.

10. The application of the flame-retardant self-catalytic flexible foam polyether polyol according to any one of claims 1-5, characterized in that, It is used in the preparation of soft polyurethane foam.

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