Multi-element synergistic flame-retardant polymer polyol and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane, and particularly relates to multi-element synergistic flame-retardant polymer polyol and a preparation method thereof. The flame-retardant polyether polyol is prepared from phosphorus-halogen mixed flame-retardant basic polyether polyol, a halogen-containing flame-retardant vinyl unsaturated monomer, a silicon-containing flame-retardant vinyl unsaturated monomer, a nitrogen-containing modified polyether dispersant, styrene, acrylonitrile, an initiator and a chain transfer agent through reaction. The halogen-containing monomer introduced into the POP polymerization monomer directly participates in free polymerization, and cooperates with the flame-retardant elements in the basic polyether, so that the content of the flame-retardant elements in the POP can be effectively increased, and the flame retardance is improved. A vinyl silicon structure is added in a POP polymeric monomer, and a silicon element is introduced into a molecular chain, so that the flame retardance is improved, the hydrophobicity of POP can be improved, and the viscosity of the composite material is reduced. The macromolecular nitrogen-containing dispersing agent forms a nitrogen-phosphorus-bromine ternary synergistic flame-retardant system by adopting a DMC catalytic process and a polyurethane synthesis technology, so that the flame retardance of POP is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and particularly relates to a multi-component synergistic flame-retardant polymer polyol and a preparation method thereof. Background Art

[0002] Polyurethane foam is widely used in everyday applications, including carpets, furniture, and transportation. However, polyurethane foam is flammable, and flame retardancy is a significant challenge for the industry. In addition to traditional additive flame retardants, flame-retardant polyethers have evolved into a variety of flame-retardant methods, including biomass-based, halogen-based, and phosphorus-based flame retardants. Biomass-based flame retardant methods, such as phosphorus-containing castor oil and straw liquefaction, are costly and have low yields, making them difficult to compete with traditional halogen-based flame retardants. Halogen-based flame retardant methods, such as patent CN102633972A, utilize epichlorohydrin hydrolysis followed by a reaction with a halogenated aromatic diphenol, but the process is relatively complex. Patent CN118005882A uses hydrobromic acid as a halogen source and concentrated sulfuric acid, posing a high safety risk. Polymer polyols (POPs), a key component of flexible polyurethane foam, effectively improve the foam's open cell structure, hardness, and load-bearing capacity by filling the polyurethane network with polymer particles. The flame retardancy of POP mainly utilizes flame retardant vinyl monomers, such as allylmethylaminodiphenylphosphonate, vinylphosphonic acid, etc., to introduce phosphorus elements or bromine-containing vinyl monomers, such as 2,3-dibromostyrene, into polymer polyols.

[0003] POP components include basic polyethers, dispersants, and polymerized monomers. However, current research on the flame retardancy of POP focuses only on the introduction of flame-retardant polymerized monomers, without conducting detailed and in-depth research on the flame retardancy of components such as basic polyethers and dispersants. Therefore, improving the flame retardancy of raw materials such as basic polyethers and dispersants in POP and adopting a multi-faceted synergistic approach are key to improving the flame retardancy of POP. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a multi-component synergistic flame-retardant polymer polyol. The multi-component synergistic flame-retardant polymer polyol of the present invention can improve the dispersibility and content of flame-retardant elements such as phosphorus, bromine, and silicon in POP.

[0005] The present invention also provides a preparation method thereof, which is simple and easy to implement, and the prepared POP has excellent flame retardant performance and hydrophobicity.

[0006] The multi-component synergistic flame-retardant polymer polyol of the present invention is prepared by reacting a phosphorus-halogen mixed flame-retardant basic polyether polyol, a halogen-containing flame-retardant ethylenically unsaturated monomer, a silicon-containing flame-retardant ethylenically unsaturated monomer, a nitrogen-containing modified polyether dispersant, styrene, acrylonitrile, an initiator, and a chain transfer agent.

[0007] The preparation method of the phosphorus-halogen mixed flame-retardant basic polyether polyol is as follows: trihydroxymethylphosphine oxide (THPO) is used as an initiator to react with an epoxy compound to prepare a phosphorus-containing polyether polyol; and then one or two of tetrachlorobisphenol A and tetrabromobisphenol A, phosphorus-containing polyether polyol, and polyether polyol are used as initiators to react with the epoxy compound to obtain the polyether polyol.

[0008] The halogen-containing flame-retardant ethylenically unsaturated monomer is one or more of 2-chloroacrylonitrile, 2-bromostyrene, and 3-bromostyrene; the silicon-containing flame-retardant ethylenically unsaturated monomer is one of vinyltrimethoxysilane and ethylene (chloromethyl)dimethoxysilane.

[0009] The nitrogen-containing modified polyether dispersant is synthesized from nitrogen-containing polyether and unsaturated isocyanate.

[0010] The nitrogen-containing polyether has a functionality of 4-5.7, a number average molecular weight of 10,000-11,500 g / mol, and the nitrogen source is tris(2-hydroxyethyl)isocyanurate (THEIC).

[0011] It includes the following three steps: 1) Select a high-functionality initiator to react with epoxide in the presence of a catalyst, and obtain a polyether polyol intermediate after purification; 2) The polyether polyol intermediate and THEIC as a composite initiator react with epoxide in the presence of a catalyst to produce nitrogen-containing polyether with a functionality of 4-5.7; 3) The nitrogen-containing polyether with a functionality of 4-5.7 and the unsaturated isocyanate are polymerized and terminated in the presence of a catalyst.

[0012] The initiator in step 1) is one or both of solid sorbitol and liquid sorbitol, preferably liquid sorbitol; The catalyst in step 1) is one or more of alkali metals or phosphazene salts; The number average molecular weight of the polyether polyol intermediate in step 1) is 900-2000 g / mol, preferably 1500-1800 g / mol.

[0013] The unsaturated isocyanate in step 3) is one or more of 3-isopropyl-dimethylbenzyl isocyanate, 2-ethyl methacrylate isocyanate, and ethyl isocyanate acrylate. The catalyst used is bismuth or zinc. The reaction temperature is 70-90°C, preferably 80°C.

[0014] The initiator is azo or peroxide, and the amount of the initiator is 0.2-0.5% of the total mass of the phosphorus-halogen mixed flame-retardant basic polyether polyol, the halogen-containing flame-retardant ethylenically unsaturated monomer and the silicon-containing flame-retardant ethylenically unsaturated monomer.

[0015] The initiator is one of dimethyl azobisisobutyrate and tert-amyl peroxy-2-ethylhexanoate; the nitrogen-containing modified polyether dispersant is 1-11% of the total mass of the phosphorus-halogen mixed flame-retardant basic polyether polyol and the ethylenically unsaturated monomer.

[0016] The chain transfer agent is one or more of methanol, ethanol, butanol, isopropanol and mercaptan, preferably isopropanol; the amount of the chain transfer agent is 3-10% of the total mass of the phosphorus-halogen mixed flame retardant basic polyether polyol, the halogen-containing flame retardant ethylenically unsaturated monomer and the silicon-containing flame retardant ethylenically unsaturated monomer.

[0017] Preferably, the mass ratio of the halogen-containing flame-retardant ethylenically unsaturated monomer to the silicon-containing flame-retardant ethylenically unsaturated monomer is 5-10:1, more preferably 10:1.

[0018] The method for preparing the multi-component synergistic flame-retardant polymer polyol of the present invention comprises the following steps: (1) Synthesizing a pre-reactant using styrene, acrylonitrile and nitrogen-modified polyether dispersant in the presence of a chain transfer agent and an initiator; (2) The pre-reactant, the phosphorus-halogen mixed flame-retardant basic polyether polyol, the halogen-containing flame-retardant ethylenically unsaturated monomer and the silicon-containing flame-retardant ethylenically unsaturated monomer are reacted in the presence of an initiator to obtain the multi-component synergistic flame-retardant polymer polyol.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. POP base polyether is synthesized by screening reactive flame retardant initiators to synthesize structural flame retardant polyether polyols containing phosphorus-halogen flame retardant elements. The synthesis method is simple, low-cost and easy to industrialize. The halogen-containing monomers introduced into the POP polymerization monomers directly participate in free polymerization and cooperate with the flame retardant elements in the base polyether, which can effectively increase the content of flame retardant elements in POP and improve flame retardancy.

[0020] 2. Adding vinyl silicon structure to the POP polymerization monomer and introducing silicon elements into the molecular chain can not only increase the flame retardancy but also improve the hydrophobicity of POP, which can be used to reduce the viscosity of the composite material, making it easier for downstream customers to use.

[0021] 3. The macromolecular nitrogen-containing dispersant adopts DMC catalytic process and polyurethane synthesis technology, which is green and environmentally friendly, with a simple and easy synthesis method, and the synthesis process can reduce "three wastes"; the introduction of nitrogen element into the macromolecular dispersant forms a nitrogen, phosphorus and bromine ternary synergistic flame retardant system, further improving the flame retardancy of POP. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the examples.

[0023] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0024] F5631, Shandong Yinuowei New Materials Co., Ltd.; C305, Shandong Yinuowei New Materials Co., Ltd.; Liquid sorbitol, VC grade, Shandong Tianli Pharmaceutical Co., Ltd.; Trishydroxymethylphosphine oxide (THPO), Hubei Xingfa Group; Tris(2-hydroxyethyl)isocyanurate (THEIC), Huaan Hongjiang Chemical Co., Ltd. Modified DMC, Jiangsu Bader Polyurethane Co., Ltd.; Silicone oil, L580, Zhongshan Dongjun Chemical Co., Ltd.; Toluene diisocyanate, T-80, Cangzhou Dahua Group Co., Ltd.

[0025] The product is prepared by reacting phosphorus-halogen mixed flame-retardant basic polyether polyol, halogen-containing flame-retardant ethylenically unsaturated monomer, silicon-containing flame-retardant ethylenically unsaturated monomer, nitrogen-containing modified polyether dispersant, initiator and chain transfer agent.

[0026] Preparation Example 1: Preparation of phosphorus-halogen mixed flame-retardant base polyether polyol 1 280 g of THPO and 7 g of KOH were added to a pressure-resistant reactor, heated to 100°C and dehydrated for 2 h, 500 g of propylene oxide was slowly added, and after the addition was completed, the internal pressure was maintained for 1 h, vacuum stripping was performed for 0.5 h, and the temperature was lowered. 15 g of magnesium aluminum silicate adsorbent was added, and the mixture was dehydrated and dried. The hydroxyl value of the obtained polyol was 480.5 mg KOH / g after testing the THPO polyether (phosphorus-containing polyether polyol). 50g of C305, 140g of THPO polyether, 20g of tetrachlorobisphenol A, 257g of tetrabromobisphenol A and 0.3g of modified DMC were added to a pressure reactor, the temperature was raised to 130°C and dehydrated for 2h, 2540g of a mixed liquid of propylene oxide and ethylene oxide was slowly added, the internal pressure was maintained for 1h after the addition was completed, vacuum stripping was performed for 0.5h, and the temperature was lowered. The hydroxyl value of the phosphorus-halogen mixed flame retardant base polyether polyol 1 was tested to be 47.1 mgKOH / g.

[0027] Preparation Example 2: Preparation of Phosphorus-Halogen Mixed Flame-Retardant Basic Polyether Polyol 2 50 g of C305, 70 g of THPO polyether (Preparation Example 1), 30 g of tetrachlorobisphenol A, 380.8 g of tetrabromobisphenol A and 0.3 g of modified DMC were added to a pressure reactor, the temperature was raised to 130°C and dehydrated for 2 h, 2560 g of a mixed liquid of propylene oxide and ethylene oxide was slowly added, the internal pressure was maintained for 1 h after the addition was completed, vacuum stripping was performed for 0.5 h, the temperature was lowered, and the hydroxyl value of the polyol obtained by testing the basic polyether was 48.4 mgKOH / g.

[0028] Preparation Example 3: Preparation of nitrogen-containing modified polyether dispersant 1 260 g of liquid sorbitol and 5 g of KOH were added to a pressure-resistant reactor, and the temperature was raised to 110° C. for dehydration for 6 h. 1395 g of propylene oxide was slowly added. After the addition was completed, the internal pressure was maintained for 1 h, and the monomers were removed under vacuum for 0.5 h. The temperature was lowered, and 22.8 g of phosphoric acid and 52.5 g of water were added for neutralization. 2 g of magnesium aluminum silicate as an adsorbent was added, and the mixture was dehydrated and dried. The hydroxyl value of the polyol obtained by testing the polyether intermediate 1 was 224.2 mgKOH / g. 300g of polyether polyol intermediate 1 and 210g of THEIC were added to a pressure reactor. The temperature was raised to 130°C for 3 hours. 0.05g of DMC catalyst was added and dehydration was continued for 1 hour. 30g of propylene oxide was added dropwise to initiate polymerization. A mixture of 7990g of propylene oxide and 1500g of ethylene oxide was then added. After the addition of the ingredients was complete, the internal pressure was maintained for 1 hour. Demonomerization was performed for 0.5 hour before the reaction was discharged. The hydroxyl value of nitrogen-containing polyether 1 was 22.6 mgKOH / g, and the functionality was 4.

[0029] 1000g of nitrogen-containing polyether 1 and 20.1g of 3-isopropyl-dimethylbenzyl isocyanate were added with 1g of bismuth isooctanoate, and the temperature was raised to 80°C. The infrared spectrum was recorded at 2261cm -1 The disappearance of the peak at is the end point of the reaction.

[0030] Preparation Example 4: Preparation of Nitrogen-Containing Modified Polyether Dispersant 2 1350g of polyether polyol intermediate 1 and 26.2g of THEIC were added to a pressure reactor. The temperature was raised to 130°C for 3 hours. 0.05g of DMC catalyst was added and dehydration was continued for 1 hour. 30g of propylene oxide was added dropwise to initiate polymerization. A mixture of 7990g of propylene oxide and 1500g of ethylene oxide was then added. After the addition of the ingredients was complete, the internal pressure was maintained for 1 hour. Demonomerization was performed for 0.5 hour before the reaction was discharged. The hydroxyl value of the nitrogen-containing polyether 2 was 28.1 mgKOH / g, and the functionality was 5.7.

[0031] 1150 g of the nitrogen-containing polyether 2, 78 g of 2-isocyanatoethyl methacrylate, and 71 g of isocyanate ethyl acrylate were added with 1.2 g of bismuth isooctanoate, and the mixture was heated to 80°C. The infrared spectrum was recorded at 2261 cm -1 The disappearance of the peak at is the end point of the reaction.

[0032] The preparation method of the multi-component synergistic flame-retardant polymer polyol comprises the following steps: (1) Preparation of pre-reactant: A mixture of nitrogen-modified polyether dispersant 1 and 2 prepared in Preparation Example, isopropyl alcohol, styrene (SM), acrylonitrile (AN), and dimethyl azobisisobutyrate was added to a batching tank. The mixture was pumped from the feed tank to a static mixer via a horizontal flow pump and then fed sequentially into two series-connected reactors for polymerization. The mixing reaction temperature in both reactors was 110±5°C, and the residence time in each reactor was 60 minutes. The pre-reactant from the second reactor was cooled in a cooler and collected for later use. The weight percentages of PA (prepared with nitrogen-modified polyether dispersant 1) or PB (prepared with nitrogen-modified polyether dispersant 2), isopropyl alcohol, styrene (SM), acrylonitrile (AN), and initiator were 24%, 59.8%, 8%, 8%, and 0.2%, respectively.

[0033] (2) Preparation of polymer polyols: The pre-reactants PA, PB, phosphorus-halogen mixed flame retardant base polyether polyol, 2-bromostyrene, 2-chloroacrylonitrile, a mixture of vinyltrimethoxysilane and tert-amyl peroxide-2-ethylhexanoate are respectively prepared, and F5631, styrene, and acrylonitrile used in the comparative example are prepared at the same time, added to the ingredient tank, and the material is transported from the feed tank to the static mixer by a horizontal flow pump, and then sequentially enters the first reactor and the second reactor through the feed pipe to allow each component to undergo a sufficient mixing reaction, wherein the reaction temperature of the two reactors is 125±2°C, and the mixture stays in the two reactors for 60 minutes. The crude product from the second reactor enters the desing kettle and is vacuumed to remove unreacted volatiles. The raw material mass content of Examples 1-4 and Comparative Examples 1-4 is shown in Table 1 below, wherein the amount of initiator is calculated separately based on the total mass of the raw materials, and the product performance test results of Examples 1-4 and Comparative Examples 1-4 are shown in Table 2.

[0034] Table 1 Raw material mass content of Examples 1-4 and Comparative Examples 1-4

[0035] Table 2 Product performance test table of Examples 1-4 and Comparative Examples 1-4

[0036] The POP prepared in the examples and comparative examples was compounded according to the formula shown in Table 3 and then subjected to flame retardancy characterization. The foam limiting oxygen index test data are shown in Table 4: Table 3 POP compound formula

[0037] Table 4 Foam Limiting Oxygen Index Test Data

[0038] By comparison, it was found that compared with the traditional POP in Comparative Example 4, the POP prepared by introducing flame retardant elements can significantly improve the flame retardant effect of the foam sponge; by comparing the embodiment with Comparative Examples 1 to 3, it was found that the multi-component synergy of flame retardant elements is more conducive to the improvement of the flame retardant effect.

Claims

1. A multi-component synergistic flame retardant polymer polyol, characterized in that: The invention is prepared by reacting phosphorus-halogen mixed flame-retardant basic polyether polyol, halogen-containing flame-retardant ethylenically unsaturated monomer, silicon-containing flame-retardant ethylenically unsaturated monomer, nitrogen-containing modified polyether dispersant, styrene, acrylonitrile, initiator and chain transfer agent.

2. The multi-component synergistic flame-retardant polymer polyol according to claim 1, characterized in that: The preparation method of the phosphorus-halogen mixed flame-retardant basic polyether polyol is as follows: trihydroxymethylphosphine oxide is used as an initiator to react with an epoxy compound to prepare a phosphorus-containing polyether polyol; and one or two of tetrachlorobisphenol A and tetrabromobisphenol A, phosphorus-containing polyether polyol, and polyether polyol are used as initiators to react with the epoxy compound to obtain the polyether polyol.

3. The multi-component synergistic flame-retardant polymer polyol according to claim 1, characterized in that: The halogen-containing flame-retardant ethylenically unsaturated monomer is one or more of 2-chloroacrylonitrile, 2-bromostyrene, and 3-bromostyrene; the silicon-containing flame-retardant ethylenically unsaturated monomer is one of vinyltrimethoxysilane and ethylene (chloromethyl)dimethoxysilane.

4. The multi-component synergistic flame-retardant polymer polyol according to claim 1, characterized in that: The nitrogen-containing modified polyether dispersant is synthesized from nitrogen-containing polyether and unsaturated isocyanate.

5. The multi-component synergistic flame-retardant polymer polyol according to claim 4, characterized in that: The unsaturated isocyanate is one or more of 3-isopropyl-dimethylbenzyl isocyanate, 2-ethyl methacrylate isocyanate, and ethyl isocyanate acrylate.

6. The multi-component synergistic flame-retardant polymer polyol according to claim 4, characterized in that The nitrogen-containing polyether has a functionality of 4-5.7, a number average molecular weight of 10,000-11,500 g / mol, and the nitrogen source is tris(2-hydroxyethyl)isocyanurate.

7. The multi-component synergistic flame-retardant polymer polyol according to claim 1, characterized in that: The initiator is one of dimethyl azobisisobutyrate and tert-amyl peroxy-2-ethylhexanoate.

8. The multi-component synergistic flame-retardant polymer polyol according to claim 7, characterized in that: The mass ratio of the halogen-containing flame-retardant ethylenically unsaturated monomer to the silicon-containing flame-retardant ethylenically unsaturated monomer is 5-10:

1.

9. The multi-component synergistic flame-retardant polymer polyol according to claim 1, characterized in that: The chain transfer agent is isopropyl alcohol.

10. A method for preparing the multi-component synergistic flame-retardant polymer polyol according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Synthesizing a pre-reactant using styrene, acrylonitrile and nitrogen-modified polyether dispersant in the presence of a chain transfer agent and an initiator; (2) The pre-reactant and phosphorus-halogen mixed flame-retardant basic polyether polyol, halogen-containing flame-retardant ethylenically unsaturated monomer and silicon-containing flame-retardant ethylenically unsaturated monomer are reacted in the presence of an initiator to obtain the multi-component synergistic flame-retardant polymer polyol.

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