Silane-terminated reactive phosphate flame retardant, preparation method thereof and application of silane-terminated reactive phosphate flame retardant in building external wall thermal insulation polyurethane

Abstract

The invention discloses a silane-terminated reactive phosphate flame retardant, a preparation method thereof and application of the silane-terminated reactive phosphate flame retardant in building external wall thermal insulation polyurethane, and belongs to the technical field of macromolecular flame-retardant materials. The structure of the flame retardant is (RO) 3Si-Z-NH-COO-[X-NH-COO] n-Y-O-P (= O) (OCH3) CH3, Z is a C2-C6 alkylene group, X is a C4-C12 alkylene group, n is 1-5, and Y is a C2-C6 hydroxyl-substituted alkylene group, so that not only is good compatibility considered, but also the cohesiveness with a building base material is greatly improved, and the flame retardant can be applied to the field of building materials. A phosphorus-based flame-retardant source, a long-chain flexible spacer group and a hydrolyzable silane end group integrated in a molecular structure serve as polyol components to directly participate in polyurethane reaction, so that the flame-retardant grade and the heat preservation property of the foam are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer flame retardant materials technology, specifically relating to a silane-terminated reactive phosphate flame retardant, its preparation method, and its application in polyurethane for building exterior wall insulation. Background Technology

[0002] Energy-saving insulation of building walls is a key focus in modern construction, and rigid polyurethane foam is widely used in building energy conservation due to its excellent insulation performance. However, because ordinary rigid polyurethane foam is a polymer material, its oxygen index is only about 17 without the addition of flame retardants, making it highly flammable under normal conditions.

[0003] Currently, most polyurethane insulation materials on the market improve their flame retardancy by adding flame retardants, such as DMMP and tris(2-chloropropyl)phosphate (TCPP). However, traditional additive flame retardants (such as TCPP and DMMP) have problems such as easy migration and volatilization, affecting the long-term dimensional stability and thermal conductivity of the foam, and insufficient adhesion to the substrate. While reactive flame retardants can solve the migration problem, they often impair the flexibility or interfacial adhesion of the foam. For example, the reactive flame retardant disclosed in Chinese patent document (application number 202010334508.0) has the following structural formula: Where R is a C1-C18 alkyl chain; m is an integer of 1 or 2; and X is Cl or Br.

[0004] Therefore, developing a single molecular structure that can simultaneously impart durable flame retardancy, good flexibility, and high adhesion to substrates to polyurethane foam through chemical bonds has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a silane-terminated reactive phosphate flame retardant. The prepared flame retardant integrates a phosphorus-based flame retardant source, a long-chain flexible spacer group, and a hydrolyzable silane end group in its molecular structure. It can directly participate in the polyurethane reaction as a polyol component and not only has excellent flame retardant properties, dimensional stability, and thermal insulation properties, but also high compressive strength and adhesive strength.

[0006] The technical solution adopted by this invention to solve the above problems is: a method for preparing a silane-terminated reactive phosphate flame retardant, comprising the following steps:

[0007] S1. In the presence of a catalyst, dimethyl methylphosphonate undergoes a ring-opening esterification reaction with glycidyl to obtain a hydroxy phosphate intermediate A HO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3;

[0008] S2. In the absence of water and catalyst, the intermediate A obtained in step S1 is reacted with an excess of long-chain flexible diisocyanate to generate a prepolymer B with isocyanate groups at the end.

[0009] S3. React the prepolymer B obtained in step S2 with aminoalkoxysilane to obtain a silane-terminated reactive phosphate flame retardant.

[0010] Preferably, the catalyst in step S1 is a tertiary amine, quaternary ammonium salt, or phosphine catalyst, and the glycidol is 2,3-epoxy-1-propanol.

[0011] More preferably, the catalyst is triethylamine, N,N-dimethylbenzylamine, tetrabutylammonium bromide, or triphenylphosphine.

[0012] Preferably, the long-chain flexible diisocyanate in step S2 is hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or decane diisocyanate.

[0013] Preferably, the catalyst in step S2 is dibutyltin dilaurate or stannous octoate.

[0014] Preferably, the aminoalkoxysilane in step S3 is aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or aminoethylaminopropyltrimethoxysilane.

[0015] Preferably, the reaction temperature in step 1 is 60-90℃, the reaction temperature in step 2 is 40-70℃, and the reaction temperature in step 3 is 30-60℃.

[0016] Preferably, in step S2, the long-chain flexible diisocyanate is added in batches to the reactor containing intermediate A, dehydrating agent and catalyst. Specifically, half of the amount is added slowly first and reacted for at least 1.5 hours, and then the remaining amount is added dropwise.

[0017] Another object of the present invention is to provide a silane-terminated reactive phosphate flame retardant, wherein the silane-terminated reactive phosphate flame retardant is prepared by the above-described method for preparing silane-terminated reactive phosphate flame retardants.

[0018] The structure of the silane-terminated reactive phosphate flame retardant is shown below.

[0019] (RO)3Si-Z-NH-COO-[X-NH-COO] n -YOP(=O)(OCH3)CH3

[0020] Wherein, R is selected from C1-C4 alkyl groups; Z is a C2-C6 alkylene group; X is a C4-C12 alkylene group; n is 1 to 5; Y is a C2-C6 alkylene group, which may optionally be substituted with one or more hydroxyl groups.

[0021] The short steric hindrance of the Z-chain in the flame retardant structure is one of the key factors affecting compatibility with polyurethane, mechanical properties of the foam material, and adhesion between the foam material and building substrates. Smaller steric hindrance facilitates rapid hydrolysis, allowing for a full reaction with the hydroxyl groups on the surface of building substrates such as cement and ceramics after foaming, thus improving adhesion. However, smaller steric hindrance affects the overall polarity of the flame retardant, which is detrimental to compatibility with polyurethane. Increasing the Z-chain length while ensuring hydrolysis can improve compatibility with polyurethane, but longer carbon chains will enhance flexibility, leading to excessively high activity of silane end groups, affecting effective arrangement at the interface, and impacting the flame retardancy and mechanical properties of the foam material. To balance good flame retardancy, adhesion to building substrates, compatibility with polyurethane, and mechanical properties of foam materials, a silane-terminated reactive phosphate flame retardant was obtained by using C2-C6 alkylene groups, X (C4-C12 alkylene groups), n (1 to 5), and Y (C2-C6 hydroxyl-substituted alkylene groups). This resulted in a silane-terminated reactive phosphate flame retardant that not only maintains good compatibility but also significantly improves adhesion to building substrates. The phosphorus-based flame retardant source, long-chain flexible spacer group, and hydrolyzable silane end group integrated into the molecular structure directly participate in the polyurethane reaction as polyol components, greatly enhancing the flame retardancy and thermal insulation properties of the foam.

[0022] Another object of the present invention is to provide an application of a silane-terminated reactive phosphate flame retardant in building exterior wall insulation polyurethane, wherein the building exterior wall insulation polyurethane comprises the following components: polyol, catalyst, foam stabilizer, blowing agent and isocyanate, wherein the polyol includes the above-mentioned silane-terminated reactive phosphate flame retardant, and the amount of the silane-terminated reactive phosphate flame retardant added is 10-40% of the mass of the polyol (with 30% being the optimal amount to obtain the foam material with the best comprehensive performance).

[0023] Preferably, the polyol further includes polyether polyol;

[0024] And / or, the mass ratio of polyol to isocyanate is 1:1;

[0025] And / or, the isocyanate is polymeric MDI.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] This invention relates to a silane-terminated reactive phosphate flame retardant, a multifunctional reactive flame retardant that integrates a phosphorus-based flame retardant source, long-chain flexible spacer groups, and hydrolyzable silane end groups in its molecular structure. It can directly participate in polyurethane reactions as a polyol component, significantly improving the flame retardancy rating, mechanical toughness, and adhesion strength of the foam to building substrates. The phosphorus element provides highly efficient flame retardancy, while the flexible long chains ensure high compatibility between the flame retardant molecules and the polyurethane matrix, without disrupting the closed-cell structure of the foam, thus maintaining excellent initial and long-term thermal insulation performance. After foam curing, the hydrolyzable silane end groups can chemically react with hydroxyl groups on the surface of building substrates such as cement, steel, and ceramics to form strong Si-O- covalent bonds, greatly improving adhesion strength and the system's water resistance and weather resistance. Detailed Implementation

[0028] To further understand the purpose, content, and advantages of this invention, specific embodiments of the invention are described in detail below. However, these embodiments are not limited to the examples described below and should be freely combined according to actual circumstances. The endpoints and values ​​of the ranges disclosed herein are not limited to the precise ranges and values. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] In some embodiments, the structure of a silane-terminated reactive phosphate flame retardant is shown below:

[0030] (RO)3Si-Z-NH-COO-[X-NH-COO] n -YOP(=O)(OCH3)CH3

[0031] Wherein, R is selected from C1-C4 alkyl groups; Z is a C2-C6 alkylene group; X is a C4-C12 alkylene group; n is 1 to 5; Y is a C2-C6 alkylene group, which may optionally be substituted with one or more hydroxyl groups.

[0032] The short steric hindrance of the Z-chain in the flame retardant structure is one of the key factors affecting compatibility with polyurethane, mechanical properties of the foam material, and adhesion between the foam material and building substrates. Smaller steric hindrance facilitates rapid hydrolysis, allowing for a full reaction with the hydroxyl groups on the surface of building substrates such as cement and ceramics after foaming, thus improving adhesion. However, smaller steric hindrance affects the overall polarity of the flame retardant, which is detrimental to compatibility with polyurethane. Increasing the Z-chain length while ensuring hydrolysis can improve compatibility with polyurethane, but longer carbon chains will enhance flexibility, leading to excessively high activity of silane end groups, affecting effective arrangement at the interface, and impacting the flame retardancy and mechanical properties of the foam material. To balance good flame retardancy, adhesion to building substrates, compatibility with polyurethane, and mechanical properties of foam materials, a silane-terminated reactive phosphate flame retardant was obtained by using C2-C6 alkylene groups, X (C4-C12 alkylene groups), n (1 to 5), and Y (C2-C6 hydroxyl-substituted alkylene groups). This resulted in a silane-terminated reactive phosphate flame retardant that not only maintains good compatibility but also significantly improves adhesion to building substrates. The phosphorus-based flame retardant source, long-chain flexible spacer group, and hydrolyzable silane end group integrated into the molecular structure directly participate in the polyurethane reaction as polyol components, greatly enhancing the flame retardancy and thermal insulation properties of the foam.

[0033] In some preferred embodiments, a method for preparing the above-mentioned silane-terminated reactive phosphate flame retardant is also provided, comprising the following steps:

[0034] S1. In the presence of a catalyst, dimethyl methylphosphonate undergoes a ring-opening esterification reaction with glycidyl ether to obtain a hydroxyphosphate intermediate A HO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3; wherein the catalyst can be a tertiary amine, a quaternary ammonium salt, or a phosphine catalyst (more preferably triethylamine, N,N-dimethylbenzylamine, tetrabutylammonium bromide, or triphenylphosphine), and the glycidyl ether is 2,3-epoxy-1-propanol;

[0035] S2. In the absence of water and a catalyst, the intermediate A obtained in step S1 is reacted with an excess of long-chain flexible diisocyanate to generate a prepolymer B with isocyanate groups at the end; wherein the long-chain flexible diisocyanate is further preferably hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or decane diisocyanate; the catalyst is further preferably dibutyltin dilaurate or stannous octoate.

[0036] S3. The prepolymer B obtained in step S2 is reacted with an aminoalkoxysilane to obtain a silane-terminated reactive phosphate flame retardant. The aminoalkoxysilane is aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or aminoethylaminopropyltrimethoxysilane.

[0037] In some preferred embodiments, the reaction temperature in step 1 is 60-90°C (more preferably 70-85°C), the reaction temperature in step 2 is 40-70°C, and the reaction temperature in step 3 is 30-60°C.

[0038] In some preferred embodiments, in order to maximize the reduction of heat conduction and increase compressive strength, the long-chain flexible diisocyanate is added in batches to the reactor containing intermediate A, dehydrating agent and catalyst in step S2. Specifically, half of the amount is added slowly and reacted for at least 1.5 hours before the remaining amount is added dropwise.

[0039] In some embodiments, a method for preparing polyurethane foam is also provided, including controlling the amount of silane-terminated reactive phosphate flame retardant added to be 10-40% of the mass of the polyol.

[0040] In some preferred embodiments, the amount of silane-terminated reactive phosphate flame retardant added is controlled to be 30% of the mass of the polyol, and the mass ratio of polyol to isocyanate is 1:1.

[0041] The present invention will be further described in detail below with reference to the embodiments:

[0042] Example 1

[0043] A method for preparing a silane-terminated reactive phosphate flame retardant includes the following steps:

[0044] (1) Synthesis of intermediate A: 124 g (1.0 mol) of dimethyl methylphosphonate, 74 g (1.0 mol) of glycidyl ether, and 1.0 g of triethylamine catalyst were added to a 500 mL three-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen inlet. Under nitrogen protection, the temperature was slowly raised to 80 °C, and the reaction was stirred for 6 hours. After the reaction was completed, a clear viscous liquid intermediate A HO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3 was obtained.

[0045] (2) Synthesis of prepolymer B: 100g of the prepared intermediate A was added to a dry three-necked flask, and 4A molecular sieve was added as a dehydrating agent. The mixture was then dehydrated under vacuum at 60°C for 1 hour. Then, 0.1g of dibutyltin dilaurate catalyst was added, and under nitrogen protection, 175g (1.04 mol) of excess hexamethylene diisocyanate (HDI) was slowly added dropwise at 50°C. After the addition was complete, the temperature was raised to 60°C and the reaction was continued for 3 hours to obtain prepolymer B with -NCO terminal.

[0046] (3) Synthesis of silane-terminated reactive phosphate flame retardants:

[0047] 150g of prepolymer B was placed in a reaction flask, and 44g (0.2mol) of aminopropyltriethoxysilane was slowly added dropwise at 40°C. After the addition was complete, the temperature was controlled at 45°C and the reaction was maintained for 2 hours. After the reaction was completed, a silane-terminated reactive phosphate flame retardant was obtained.

[0048] A polyurethane foam material for building exterior wall insulation, comprising component A and component B.

[0049] Component A comprises the following components in parts by weight:

[0050] Polyether polyol Donol 670 (produced by Shanghai Dongda Chemical Co., Ltd., with a hydroxyl value of 475-515 mg KOH / g and a viscosity of 35000-45000 mPa·s): 70 parts

[0051] Silane-terminated reactive phosphate flame retardant: 30 parts

[0052] Foam stabilizer (silicone oil L-6900): 2.0 parts

[0053] Catalyst (pentamethyldiethylenetriamine PC-5): 1.5 parts

[0054] Catalyst (triethylenediamine A-33): 0.5 parts

[0055] Foaming agent (cyclopentane): 15 parts

[0056] Component B: Polymer MDI (purchased from Yantai Wanhua, model PM-200, NCO content 31%): 130 parts

[0057] At room temperature, the raw materials of component A are stirred evenly, and then mixed with component B under high speed for 10 seconds. The mixture is then poured into a mold at 40°C to foam, and cured at 60°C to obtain rigid polyurethane foam material.

[0058] Example 2

[0059] A method for preparing a silane-terminated reactive phosphate flame retardant includes the following steps:

[0060] (1) Synthesis of intermediate A: 124 g (1.0 mol) of dimethyl methylphosphonate, 74 g (1.0 mol) of glycidyl ether, and 1.0 g of tetrabutylammonium bromide catalyst were added to a 500 mL three-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen inlet. Under nitrogen protection, the temperature was slowly raised to 70 °C, and the reaction was stirred for 7 hours. After the reaction was completed, a clear viscous liquid intermediate A HO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3 was obtained.

[0061] (2) Synthesis of prepolymer B: 100g of the prepared intermediate A was added to a dry three-necked flask, and 4A molecular sieve was added as a dehydrating agent. The mixture was vacuum dehydrated at 60°C for 1 hour. Then, 0.08g of stannous octoate catalyst was added. Under nitrogen protection, 222g (1.0 mol) of excess isophorone diisocyanate (IPDI) was slowly added dropwise at 55°C. After the addition was complete, the temperature was raised to 65°C and the reaction was continued for 4 hours to obtain prepolymer B with -NCO terminal.

[0062] (3) Synthesis of silane-terminated reactive phosphate flame retardants:

[0063] 180g of prepolymer B was placed in a reaction flask, and 41g (0.2mol) of aminopropyltrimethoxysilane was slowly added dropwise at 35°C. After the addition was complete, the temperature was controlled at 40°C and the reaction was maintained for 2.5 hours. After the reaction was completed, a silane-terminated reactive phosphate flame retardant was obtained.

[0064] A polyurethane foam material for building exterior wall insulation, comprising component A and component B.

[0065] Component A comprises the following components in parts by weight:

[0066] Polyether polyol Donol 670 (produced by Shanghai Dongda Chemical Co., Ltd., with a hydroxyl value of 475-515 mg KOH / g and a viscosity of 35000-45000 mPa·s): 70 parts

[0067] Silane-terminated reactive phosphate flame retardant: 30 parts

[0068] Foam stabilizer (silicone oil L-6900): 2.0 parts

[0069] Catalyst (pentamethyldiethylenetriamine PC-5): 1.5 parts

[0070] Catalyst (triethylenediamine A-33): 0.5 parts

[0071] Foaming agent (cyclopentane): 15 parts

[0072] Component B: Polymer MDI (purchased from Yantai Wanhua, model PM-200, NCO content 31%): 130 parts

[0073] At room temperature, the raw materials of component A are stirred evenly, and then mixed with component B under high speed for 10 seconds. The mixture is then injected into a mold to obtain rigid polyurethane foam material.

[0074] Example 3

[0075] A method for preparing a silane-terminated reactive phosphate flame retardant includes the following steps:

[0076] (1) Synthesis of intermediate A: In a 500 mL three-necked flask equipped with a stirrer, thermometer, condenser and nitrogen inlet, 124 g (1.0 mol) of dimethyl methylphosphonate, 74 g (1.0 mol) of glycidyl ether and 2.0 g of triphenylphosphine catalyst were added. Under nitrogen protection, the temperature was slowly raised to 85 °C and the reaction was stirred for 5 hours. After the reaction was completed, a clear viscous liquid intermediate AHO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3 was obtained.

[0077] (2) Synthesis of prepolymer B: 100g of the prepared intermediate A was added to a dry three-necked flask, and 4A molecular sieve was added as a dehydrating agent. The mixture was vacuum dehydrated at 60°C for 1 hour. Then, 0.1g of dibutyltin dilaurate catalyst was added. Under nitrogen protection, 87.5g (0.52 mol) of hexamethylene diisocyanate (HDI) was slowly added dropwise at 45°C. The reaction was allowed to proceed for 1.5 hours. Then, a second batch of 87.5g (0.52 mol) of HDI was added dropwise. After the addition was completed, the temperature was raised to 60°C and the reaction was continued for 2 hours to obtain prepolymer B with -NCO terminal.

[0078] (3) Synthesis of silane-terminated reactive phosphate flame retardants:

[0079] 200g of prepolymer B was placed in a reaction flask, and 59g (0.27mol) of aminopropyltriethoxysilane was slowly added dropwise at 50°C. After the addition was complete, the temperature was controlled at 60°C and the reaction was maintained for 2 hours. After the reaction was completed, a silane-terminated reactive phosphate flame retardant was obtained.

[0080] A polyurethane foam material for building exterior wall insulation, comprising component A and component B.

[0081] Component A comprises the following components in parts by weight:

[0082] Polyether polyol Donol 670 (produced by Shanghai Dongda Chemical Co., Ltd., with a hydroxyl value of 475-515 mg KOH / g and a viscosity of 35000-45000 mPa·s): 70 parts

[0083] Silane-terminated reactive phosphate flame retardant: 30 parts

[0084] Foam stabilizer (silicone oil L-6900): 2.0 parts

[0085] Catalyst (pentamethyldiethylenetriamine PC-5): 1.5 parts

[0086] Catalyst (triethylenediamine A-33): 0.5 parts

[0087] Foaming agent (cyclopentane): 15 parts

[0088] Component B: Polymer MDI (purchased from Yantai Wanhua, model PM-200, NCO content 31%): 130 parts

[0089] At room temperature, the raw materials of component A are stirred evenly, and then mixed with component B under high speed for 10 seconds. The mixture is then injected into a mold to obtain rigid polyurethane foam material.

[0090] Comparative Example 1

[0091] The only difference from Example 1 is that the silane-terminated reactive phosphate flame retardant is replaced with tris(2-chloroisopropyl) phosphate (TCPP).

[0092] Comparative Example 2

[0093] The only difference from Example 1 is that the silane-terminated reactive phosphate flame retardant is replaced with polyether polyol Donol 670, i.e., the weight of polyether polyol Donol 670 is 100 parts.

[0094] The properties of the polyurethane foam materials in Examples 1-3 and Comparative Examples 1-2 were characterized. The cement bond strength test was conducted according to GB / T 50404-2017. Specifically, foamed and cured polyurethane foam material samples were cut into 40 mm × 40 mm × original thickness specimens. Using a conventional high-strength epoxy resin adhesive (with a cured tensile strength typically not less than 30 MPa to ensure the failure mode occurs within the polyurethane foam material) used in this type of test, the specimens were bonded to the surface of a standard cement mortar block (70 mm × 70 mm × 20 mm, strength grade C25). A pressure of 1.0 kPa was applied, and after curing for 7 days under standard conditions of 23±2℃ and 50±5% relative humidity, a tensile test was performed at a rate of 5 mm / min on a universal testing machine. The failure load was recorded, and the tensile bond strength (MPa) was calculated. The failure mode was observed and recorded simultaneously. All sample samples exhibited cohesive failure within the polyurethane foam. The results are shown in Table 1.

[0095] Table 1 Performance test data of polyurethane foam materials in Examples 1-3 and Comparative Examples 1-2

[0096]

[0097] Note: The thermal conductivity coefficient is calculated based on a hot plate temperature of 35℃ and a cold plate temperature of 10℃.

[0098] As can be seen from the table above, the polyurethane foam materials with silane-terminated reactive phosphate flame retardants added in Examples 1-3 not only have excellent flame retardant properties, dimensional stability, and thermal insulation properties, but also have high compressive strength and bonding strength. As can be seen from Example 1 and Comparative Example 1, the traditional small-molecule additive flame retardant TCPP will seriously damage the closed-cell structure of polyurethane, affecting the long-term dimensional stability and thermal conductivity of the foam, as well as insufficient adhesion to the substrate. As can be seen from Example 1 and Comparative Example 2, simply increasing the amount of polyether will not only fail to achieve a high flame retardant rating, but will also affect dimensional stability and bonding performance.

[0099] As can be seen from Examples 1 and 3, Example 3 can maximize the reduction of thermal conductivity and improve compressive strength. This is because the batch addition of HDI can obtain a molecular structure with more uniform chain length and more regular sequence, which has better compatibility with polyether polyols. It can guide the formation of an unprecedentedly uniform, dense, and defect-free ideal cell structure, thereby maximizing the reduction of thermal conductivity. The regular sequence effectively promotes the microphase separation of hard and soft segments in the polyurethane network. The hard segment region aggregates to form a stronger and more effective physical crosslinking network, thereby providing higher modulus and strength when the material is under stress.

[0100] In step (1) of Examples 1-3, the reaction temperature is 70-85℃ and the reaction time is 5-7h, which can ensure complete reaction, thereby making intermediate A highly pure and improving the flame retardancy, mechanical properties and storage stability of the final foam.

[0101] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

Claims

1. A silane-terminated reactive phosphate flame retardant, characterized in that: The structure is as follows: (RO)3Si-Z-NH-COO-[X-NH-COO] n -YOP(=O)(OCH3)CH3 Wherein, R is selected from C1-C4 alkyl groups; Z is a C2-C6 alkylene group; X is a C4-C12 alkylene group; n is 1 to 5; Y is a C2-C6 alkylene group, which may optionally be substituted with one or more hydroxyl groups.

2. The preparation method of the silane-terminated reactive phosphate flame retardant as described in claim 1, characterized in that: Includes the following steps: S1. In the presence of a catalyst, dimethyl methylphosphonate undergoes a ring-opening esterification reaction with glycidyl to obtain a hydroxy phosphate intermediate with the structural formula HO-CH2CH(OH)CH2-OP(=O)(OCH3)CH3. S2. In the absence of water and catalyst, the intermediate obtained in step S1 is reacted with an excess of long-chain flexible diisocyanate to generate a prepolymer with isocyanate groups at the end; S3. The prepolymer obtained in step S2 is reacted with aminoalkoxysilane to obtain a silane-terminated reactive phosphate flame retardant.

3. The method for preparing the silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The catalyst mentioned in step S1 is a tertiary amine, quaternary ammonium salt, or phosphine catalyst.

4. The method for preparing a silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The catalyst mentioned in step S1 is triethylamine, N,N-dimethylbenzylamine, tetrabutylammonium bromide, or triphenylphosphine.

5. The method for preparing a silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The long-chain flexible diisocyanate mentioned in step S2 is hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or decane diisocyanate.

6. The method for preparing a silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The catalyst mentioned in step S2 is dibutyltin dilaurate or stannous octoate.

7. The method for preparing a silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The aminoalkoxysilane mentioned in step S3 is aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or aminoethylaminopropyltrimethoxysilane.

8. The method for preparing a silane-terminated reactive phosphate flame retardant according to claim 2, characterized in that: The reaction temperature in step 1 is 60-90℃, the reaction temperature in step 2 is 40-70℃, and the reaction temperature in step 3 is 30-60℃.

9. The application of a silane-terminated reactive phosphate flame retardant in polyurethane for building exterior wall insulation, characterized in that: The building exterior wall insulation polyurethane comprises the following components: polyol, water, catalyst, foam stabilizer, foaming agent, and isocyanate, wherein the polyol includes the silane-terminated reactive phosphate flame retardant as described in any one of claims 1-8, and the amount of the silane-terminated reactive phosphate flame retardant added is 10-40% of the mass of the polyol.

10. The application of the silane-terminated reactive phosphate flame retardant according to claim 9 in polyurethane for building exterior wall insulation, characterized in that: The amount of silane-terminated reactive phosphate flame retardant added is 30% of the mass of the polyol; And / or, the polyol further includes polyether polyols; And / or, the mass ratio of polyol to isocyanate is 1:1; And / or, the isocyanate is polymeric MDI.

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