Epoxy asphalt reaction type phosphorus-silicon flame retardant, epoxy asphalt concrete and preparation method of epoxy asphalt reaction type phosphorus-silicon flame retardant

Abstract

The invention discloses an epoxy asphalt reaction type phosphorus-silicon flame retardant, epoxy asphalt concrete and a preparation method of the epoxy asphalt reaction type phosphorus-silicon flame retardant. The epoxy asphalt reactive phosphorus-silicon flame retardant contains a diepoxy group and a phosphorus-silicon synergistic skeleton, so that the limit oxygen index of epoxy asphalt can be greatly improved, meanwhile, good mechanical properties are kept, and the migration rate of the flame retardant is reduced. Compared with the existing reaction type phosphorus-silicon flame retardant, the phosphorus-silicon flame retardant has better flame retardant property, is used for preparing epoxy asphalt concrete, not only improves the flame retardant property, but also can further improve the mechanical property and pavement performance of the asphalt concrete, and is suitable for traffic infrastructure, building municipal engineering, special industrial facilities and other key scenes. According to the method, the silane coupling agent hydrolysate and the alkyl phosphate are subjected to phosphorylation reaction, then epoxy chloropropane is used for blocking, the preparation process is simple, no halogen or heavy metal participates in the preparation process, and the method conforms to European Union REACH regulations and domestic low-toxicity and low-harm building material standards.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, more specifically, relates to an epoxy asphalt reactive phosphorus-silicon flame retardant, an epoxy asphalt concrete and a preparation method thereof. BACKGROUND

[0002] As a building material, asphalt is widely used in infrastructure construction such as bridges, roads, tunnels and airports. In order to meet the demand for improving the toughness of materials in application scenarios, epoxy resin is cured with asphalt to form an epoxy asphalt material with excellent physical, high and low temperature and fatigue resistance. However, like traditional matrix asphalt and SBS modified asphalt, the limiting oxygen index of epoxy asphalt is low, and it is easy to burn during construction and use if exposed to open flame or high temperature, releasing a large amount of heat and toxic smoke, which has a negative impact on personal health, the environment and infrastructure safety.

[0003] At present, the flame retardants for epoxy asphalt mainly include two types. One is an additive type flame retardant, which is a traditional flame retardant commonly used for asphalt, such as aluminum hydroxide, magnesium hydroxide, antimony trioxide and bromine-based flame retardant, and physical compounding of such flame retardants. This type of flame retardant does not react with epoxy asphalt, and the flame retardant performance improvement effect is limited, and the compatibility with asphalt base is poor and easy to agglomerate. Some bromine-based flame retardants also produce toxic gases when burning. The other type is a reactive flame retardant, which is embedded in the polymer matrix through chemical bonding to avoid the migration and precipitation of effective flame-retardant components to ensure sustained flame-retardant performance. However, the research on reactive flame retardants for epoxy asphalt is very limited, and there are generally problems of insufficient reaction activity and low flame-retardant efficiency. There are still the following problems: (1) Halogen-containing system flame retardants have a greater impact on the environment; (2) High addition amount leads to low economic efficiency; (3) Affecting the mechanical properties of epoxy asphalt and the road performance of epoxy asphalt concrete.

[0004] These limitations limit the popularization and application of epoxy asphalt concrete in special scenarios such as tunnels and airports.

[0005] The present application develops a phosphorus-silicon synergistic halogen-free reactive flame retardant for epoxy asphalt through original molecular design. The flame retardant integrates efficient flame-retardant elements and epoxy end groups that can participate in curing in the molecular structure, achieving a significant improvement in the limiting oxygen index of epoxy asphalt at a low amount of flame retardant, while improving the high tensile strength and toughness of epoxy asphalt, and realizing the compatibility of the flame-retardant performance, mechanical properties and road performance of epoxy asphalt concrete. SUMMARY

[0006] In order to solve the above defects or improvement needs of the prior art, the present application provides an epoxy asphalt reactive phosphorus-silicon flame retardant, an epoxy asphalt concrete and a preparation method thereof, which aims to synthesize a new epoxy-terminated phosphorus-silicon flame retardant, use the same as a reactive phosphorus-silicon flame retardant for epoxy asphalt, significantly improve the limiting oxygen index of the epoxy asphalt at a low dosage, and improve the mechanical properties of the epoxy asphalt concrete, thereby solving the technical problem that the existing flame retardants are difficult to be compatible with the flame retardant properties, mechanical properties and concrete road performance of the epoxy asphalt.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: In a first aspect of the present application, an epoxy asphalt reactive phosphorus-silicon flame retardant is provided which is an epoxy-terminated phosphorus-silicon flame retardant and has the following general formula (I): ; In the formula, R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, and methacryloxy, and R2 is selected from methyl, ethyl, propyl, and hydroxyl.

[0008] Preferably, the epoxy asphalt reactive phosphorus-silicon flame retardant has a phosphorus content of 7.2% to 9.7%, a silicon content of 6.5% to 8.8%, and an epoxy value of (0.23-0.50) eq / 100g.

[0009] Preferably, the epoxy asphalt reactive phosphorus-silicon flame retardant has R1 selected from mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, and methacryloxy, and R2 selected from methyl, ethyl, propyl, and hydroxyl.

[0010] According to a second aspect of the present application, a preparation method of the epoxy asphalt reactive phosphorus-silicon flame retardant is also provided, which comprises the following steps: (1) Hydrolysis reaction: mix a silane coupling agent and deionized water according to a molar ratio of 1:(3-5), adjust the pH of the system to 3-5, and react under an inert atmosphere at a temperature of 25°C-70°C for 1-3 hours to hydrolyze to generate a liquid trihydroxysilane intermediate and ethanol, and then distill off the generated ethanol and the deionized water in the beaker to obtain the trihydroxysilane intermediate; the general formula of the silane coupling agent is [R1(CH2)3]Si(OCH3)3, and R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, and methacryloxy; (2) Phosphorylation reaction: to the liquid trihydroxyl silane intermediate obtained in step (1), add alkyl phosphate ester in a molar amount of 1.0-1.5 times of the silane coupling agent, add catalyst in an amount of 0.3%-0.8% of the total mass of the reactants, and react at a temperature of 60-100°C for 3-5 hours to obtain a reaction product; the general formula of the alkyl phosphate ester is R2P(=O)(OCH3)2, wherein R2 is methyl, ethyl, propyl, or hydroxyl; (3) Epoxy capping reaction: slowly add epichlorohydrin to the reaction product obtained in step (2), adjust the pH of the system to 7-8, react at 70-90°C for 4-8 hours, and remove the generated hydrogen chloride at the same time to obtain a light yellow transparent final reaction product, which is the epoxy asphalt reaction-type phosphorus-silicon flame retardant.

[0011] Preferably, in the method, the silane coupling agent in step (1) is selected from one or more of KH-540, KH-560, KH-570, KH-590, KH-792, and TMSPMA.

[0012] Preferably, in the method, the alkyl phosphate ester in step (2) is selected from one or more of dimethyl methylphosphonate (DMMP), dimethyl ethylphosphonate (DMEP), and dimethyl propylphosphonate (DPrMP) in any combination; and the catalyst is selected from dibutyltin dilaurate, which is added in an amount of 0.3%-0.8% of the total mass of the silane coupling agent and the alkyl phosphate ester.

[0013] Preferably, in the method, the amount of epichlorohydrin added in step (3) is 1.2-1.8 times of the molar amount of the silane coupling agent.

[0014] According to a third aspect of the present application, there is also provided a flame-retardant modified epoxy asphalt, which comprises epoxy asphalt and an epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application.

[0015] According to a fourth aspect of the present application, there is also provided a flame-retardant epoxy asphalt concrete, which comprises an epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application.

[0016] Preferably, the flame-retardant epoxy asphalt concrete has an limiting oxygen index (LOI, %) > 30, a vertical burning rating (UL94) of V-0, and a flame retardant migration amount < 0.8 μg / m 2 .

[0017] Preferably, the flame-retardant epoxy asphalt concrete is prepared by the following method: Heat 40-100 parts of asphalt base to melting, add 30-50 parts of bisphenol A epoxy resin and 0.3-1 part of silane coupling agent, and stir to form a mixed base; Then 5-15 parts of the epoxy asphalt reactive phosphorus-silicon flame retardant as described in the present application are added, and the temperature is raised to 130-160 DEG C, and stirred uniformly; The temperature is lowered to 110-130 DEG C, the curing agent and the accelerator are added, and stirred uniformly, then 1000-1500 parts of the mineral aggregate basalt heated to 170-180 DEG C are added, and stirred at 110-130 DEG C for 5 min ± 5 s, and the flame-retardant epoxy asphalt concrete is obtained after curing.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects due to the discovery of a new synthesis method of a reactive phosphorus-silicon flame retardant: The epoxy asphalt reactive phosphorus-silicon flame retardant provided by the present application is an epoxy-terminated phosphorus-silicon flame retardant, which comprises a phosphorus acyl group, a siloxane group and an epoxy end cap, can make the limiting oxygen index of epoxy asphalt reach more than 30%, and can maintain good mechanical properties, and the migration amount of the flame retardant is less than 0.8 μg / m 2 Compared with the existing reactive phosphorus-silicon flame retardant, the present application has better flame retardant performance, and is used for preparing epoxy asphalt concrete, which not only improves the flame retardant performance, but also further improves the mechanical properties and road performance of the asphalt concrete. The epoxy asphalt reactive phosphorus-silicon flame retardant can be compatible with the flame retardant performance, mechanical properties and road performance of the epoxy asphalt concrete.

[0019] The preparation method of the epoxy asphalt reactive phosphorus-silicon flame retardant provided by the present application is prepared by hydrolysis of a silane coupling agent, phosphorylation reaction with an alkyl phosphate, and then end-capping with an epoxy chloropropane. The molecular structure contains a double epoxy group and a phosphorus-silicon synergistic skeleton, the preparation process is simple, and no halogen and heavy metal are involved, which meets the EU REACH regulations and the domestic "low toxicity and low harm" building material standards. The epoxy asphalt reactive phosphorus-silicon flame retardant prepared by the method is used for preparing asphalt concrete, which is suitable for traffic infrastructure, municipal engineering and special industrial facilities, and specifically covers key scenes such as steel bridge deck, highway tunnel, high-speed special road section, industrial roof waterproofing, underground parking lot, overpass, port pier, airport emergency repair and chemical pipeline, etc. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a general structural formula of the epoxy asphalt reactive phosphorus-silicon flame retardant.

[0021] Figure 2 is an infrared spectrum of the epoxy asphalt reactive phosphorus-silicon flame retardant synthesized in Example 1. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are merely intended to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0023] The present application provides an epoxy asphalt reactive phosphorus-silicon flame retardant, which is an epoxy-terminated phosphorus-silicon flame retardant, and has a structure shown in the following general formula (I): ; wherein R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, methacryloxy, and R2 is methyl, ethyl, propyl, hydroxyl.

[0024] The present application integrates phosphoryl (-P(=O)(OCH3)2) and siloxane skeleton (-Si-O-) in the same molecule through molecular design, forming a unique gas phase, condensed phase and interface synergistic flame-retardant mechanism. At the same time, the molecular structure also contains epoxy groups, which can chemically react with epoxy resin, thereby firmly combining with the epoxy asphalt matrix, avoiding the migration and precipitation of the flame retardant, and the flame-retardant effect is more durable. The present flame retardant is chemically bonded with the epoxy asphalt matrix, so that the limiting oxygen index of the epoxy asphalt concrete is more than 30%, while maintaining good mechanical properties, and the migration amount of the flame retardant is less than 0.8 μg / m 2 .

[0025] The phosphorus content of the epoxy-terminated phosphorus-silicon flame retardant is 7.2% to 9.7%, the silicon content is 6.5% to 8.8%, and the epoxy value is (0.23-0.50) eq / 100g. In some embodiments, R1 in the structure of the epoxy-terminated phosphorus-silicon flame retardant is selected from mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, and methacryloxy, and R2 is selected from methyl, ethyl, propyl, and hydroxyl.

[0026] In addition, the present application also provides a preparation method of the epoxy asphalt reactive phosphorus-silicon flame retardant, which comprises the following steps: (1) Hydrolysis reaction: mixing silane coupling agent and deionized water according to a molar ratio of 1:(3-5), adjusting pH to 3-5, and reacting at a temperature of 25°C-70°C under inert atmosphere for 1-3 hours to hydrolyze a liquid trihydroxysilane intermediate; the general formula of the silane coupling agent is [R1(CH2)3]Si(OCH3)3, and R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, and methacryloxy.

[0027] (2) Phosphorylation reaction: adding alkyl phosphate and catalyst to the liquid trihydroxysilane intermediate obtained in step (1), adjusting the pH to 7-8, and reacting at a temperature of 60-100°C for 3-5 hours to obtain a reaction product; the general formula of the alkyl phosphate is R2P(=O)(OCH3)2, and R2 is selected from methyl, ethyl, propyl, and hydroxyl.

[0028] (3) Epoxy capping reaction: slowly adding epichlorohydrin to the reaction product obtained in step (2), reacting at 70-90°C for 4-8 hours while removing the generated hydrogen chloride, and obtaining a light yellow liquid reaction end product, which is the epoxy asphalt reaction-type phosphorus-silicon flame retardant.

[0029] In some embodiments, the silane coupling agent in step (1) is selected from one or two or more of 3-aminopropyltrimethoxysilane (KH-540), 3-aminopropyltriethoxysilane (KH-550), 3-glycidyloxypropyltrimethoxysilane (KH-560), 3-trimethoxysilyl methyl methacrylate (KH-570), 3-mercaptopropyltrimethoxysilane (KH-590), N-3-trimethoxysilylpropyl ethylenediamine (KH-792), and 3-trimethoxysilyl propyl methacrylate (TMSPMA). The structural formula of KH-540 is “ ”, the structural formula of KH-550 is “ ”, the structural formula of KH-560 is “ ”, the structural formula of KH-570 is “ ”, the structural formula of KH-590 is “ ”, the structural formula of KH-792 is “ ”, and the structural formula of TMSPMA is “ ”.

[0030] In some embodiments, the hydrolysis reaction in step (1) is carried out under nitrogen protection, the stirring rate is 300 rpm, the pH of the reaction system is 3-5, a liquid trihydroxysilane intermediate and ethanol are generated, the generated ethanol and the deionized water in the beaker are distilled to obtain the trihydroxysilane intermediate.

[0031] In some embodiments, 1.0-1.5 times the molar amount of the silane coupling agent and 0.3%-0.8% of the catalyst (i.e., the catalyst accounts for 0.3%-0.8% of the total mass of the silane coupling agent and the alkyl phosphate) are added to the liquid trihydroxysilane intermediate obtained in step (1), and the pH of the reaction system is adjusted to 7-8.

[0032] The catalyst is selected from dibutyltin dilaurate. The alkyl phosphate is selected from dimethyl methylphosphonate (DMMP), dimethyl ethylphosphonate (DMEP), dimethyl propylphosphonate (DPrMP), or any combination of one or more of DMP. The structure of DMMP is shown in formula (I) , the structure of DMEP is shown in formula (II) , the structure of DPrMP is shown in formula (III) , and the structure of DMP is shown in formula (IV) .

[0033] Preferably, the residual trace amount of water in the liquid alkyl phosphate is removed by drying at room temperature before adding to the reaction system. The residual trace amount of water is removed to prevent hydrolysis of the raw materials, to initiate side reactions, and the like, thereby ensuring high conversion and high purity of the product.

[0034] In some embodiments, the reaction product obtained in step (2) is slowly added with 1.2-1.8 times the molar amount of silane coupling agent, and epichlorohydrin is added, and the reaction is carried out at 70-90°C for 4-8 hours to obtain a light yellow liquid reaction end product, which is the epoxy asphalt reaction-type phosphorus-silicon flame retardant.

[0035] In addition, the present application also provides a flame-retardant modified epoxy asphalt, which comprises epoxy asphalt and the epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application.

[0036] In addition, the present application also provides a flame-retardant epoxy asphalt concrete, which comprises the epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application.

[0037] In some embodiments, the flame-retardant epoxy asphalt concrete comprises 5-15 parts by mass of the epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application.

[0038] In some embodiments, the flame-retardant epoxy asphalt concrete has an limiting oxygen index (LOI, %) > 30, a vertical burning rating (UL94) of V-0, and a flame retardant migration amount < 0.8 μg / m 2 .

[0039] In some embodiments, the flame-retardant epoxy asphalt concrete is prepared as follows: (1) 40-100 parts by mass of road petroleum asphalt is heated to melt, 30-50 parts by mass of bisphenol A epoxy resin and 0.3-1 part by mass of silane coupling agent are added, and stirring is performed to form a mixed matrix. For example, stirring is performed at 800 rpm for 30 minutes to form the mixed matrix.

[0040] (2) 5-15 parts by mass of the epoxy asphalt reaction-type phosphorus-silicon flame retardant as described in the present application is added, and the temperature is raised to 130-160°C, and stirring is performed to make the mixture uniform. For example, the temperature is raised to 150°C, and high-speed dispersion is performed at 1200 rpm for 30 minutes to make the mixture uniform.

[0041] (3) cooling to 110-130°C, adding curing agent and accelerator, stirring evenly, then curing to obtain the flame-retardant epoxy asphalt mixture. For example, cooling to 120°C, adding 5-8 parts of curing agent and 1-2 parts of accelerator, stirring evenly, then adding 1000-1500 parts of mineral aggregate basalt heated to 170-180°C, stirring at 110-130°C for 5 min±5s, and curing to obtain the flame-retardant epoxy asphalt concrete. In some embodiments, the curing in step (3) is 60°C curing for 24 hours.

[0042] The curing agent is selected from polyamide curing agent, fatty amine curing agent; and the accelerator is imidazole accelerator, selected from 2-methylimidazole and 2-ethyl-4-methylimidazole.

[0043] The following are examples The silane coupling agent, alkyl phosphate and the corresponding compound of epoxy chloropropane used in the following examples have the structural formula shown in the following table.

[0044] Table 1 Structural formula of silane coupling agent, alkyl phosphate and the corresponding compound of epoxy chloropropane

[0045] Example 1

[0046] 1. Preparation of reactive flame retardant for epoxy asphalt (1) Hydrolysis reaction: 1 mol of silane coupling agent (KH-560, 3-glycidyloxypropyltrimethoxysilane) and 3 mol of deionized water were added to a 500 mL four-necked flask, and the pH was adjusted to 3.2 with dilute hydrochloric acid under nitrogen protection, stirred at 300 rpm, and reacted at 40°C for 2 hours. Hydrolysis generates liquid trihydroxysilane intermediates and ethanol, and distillation removes the generated ethanol and beaker deionized water to obtain trihydroxysilane intermediates.

[0047] (2) Phosphorylation reaction: 1.2 mol of dimethyl methylphosphonate (DMMP) and 0.5% of the total mass of raw materials of dibutyltin dilaurate (DBTDL) were added to the liquid trihydroxysilane intermediates obtained in step (1), and the temperature was raised to 60°C for 4 hours.

[0048] (3) Epoxy capping reaction: 1.5 mol of epichlorohydrin was slowly added into the product obtained in step (2), and the reaction was carried out at 80°C for 6 hours. During the reaction, triethylamine was used to adjust the pH to 7.2, and the byproduct hydrogen chloride gas was eliminated. The tail gas was collected. After the reaction was completed, the yellow transparent product (epoxy-capped phosphorus-silicon flame retardant) was obtained by distillation under reduced pressure. The epoxy asphalt reactive phosphorus-silicon flame retardant was obtained, with a phosphorus content of 7.6%, a silicon content of 6.8%, and an epoxy value of 0.50 eq / 100g. The infrared spectrum of the flame retardant synthesized in this example is shown in Figure 2

[0049] The epoxy value refers to the number of equivalents of epoxy groups (-CH2-CH(O)-CH2-) contained in 100g of epoxy resin. The larger the epoxy value, the more epoxy groups there are in 100g of resin, and the smaller the molecular weight, and the lower the viscosity of the resin. The smaller the epoxy value, the larger the molecular weight, and the relatively higher the viscosity.

[0050] 2. Preparation of epoxy asphalt concrete Bisphenol A type epoxy resin (epoxy value 0.4 eq / 100g) 40 parts, road petroleum asphalt (penetration (25°C, 100g, 5s) 70 (0.1mm)) 60 parts, polyamide curing agent (amine value 250mg KOH / g) 8 parts, 2-methylimidazole 1 part, 0.8 part of silane coupling agent KH-560.

[0051] ① According to the mass fraction, 60 parts of road petroleum asphalt was heated to 140°C to melt, 40 parts of bisphenol A epoxy resin and 0.8 parts of KH-560 were added, and stirred at 800 rpm for 30 minutes; ② 6 parts of the above epoxy-capped phosphorus-silicon flame retardant was added, and dispersed at 150°C and 1200 rpm for 1 hour; ③ The temperature was lowered to 120°C, 8 parts of polyamide curing agent and 1 part of 2-methylimidazole accelerator were added, and stirred at 3000 rpm for 1 min, then 1300 parts of AC-13 mineral aggregate basalt at 180°C was added, and stirred at 120°C for 5 min to obtain epoxy asphalt concrete.

[0052] The test piece was formed by using Marshall compaction instrument (Φ101.6mm×63.5mm), and was cured at 120°C for 4h, and then cooled to room temperature for standby.

[0053] Table 2 Asphalt concrete AC-13 mineral aggregate gradation passing rate range

[0054] Example 2 1. Preparation of reactive flame retardant for epoxy asphalt ​(1) Hydrolysis reaction: 1 mol of silane coupling agent (KH-560, 3-glycidyloxypropyltrimethoxysilane) and 3 mol of deionized water were added to a 500 mL four-necked flask, and the pH was adjusted to 3.2 with dilute hydrochloric acid under nitrogen protection, stirred at 300 rpm, and reacted at 40°C for 2 hours. The hydrolysis generated liquid trihydroxysilane intermediates and ethanol, and the generated ethanol and deionized water in the beaker were removed by distillation to obtain the trihydroxysilane intermediates.

[0055] (2) Phosphorylation reaction: 1.2 mol of dimethyl ethyl phosphonate (DMEP) and 0.5% of the total mass of the raw material DBTDL were added to the liquid trihydroxysilane intermediates obtained in step (1), and the temperature was raised to 60°C for 4 hours.

[0056] (3) Epoxy capping reaction: 1.5 mol of epichlorohydrin was slowly added to the product obtained in step (2), and the reaction was carried out at 80°C for 6 hours. During the reaction, the pH was adjusted to 7.2 with triethylamine, and the generated HCl gas was eliminated. Attention should be paid to collect the tail gas. After the reaction was completed, the product was obtained by distillation under reduced pressure to obtain a light yellow transparent epoxy-capped phosphorus-silicon flame retardant, which was an epoxy asphalt reactive phosphorus-silicon flame retardant. The phosphorus content was 7.6%, the silicon content was 6.7%, and the epoxy value was 0.48 eq / 100 g.

[0057] 2. Preparation of epoxy asphalt concrete: Bisphenol A type epoxy resin (epoxy value 0.4 eq / 100 g) 40 parts, road petroleum asphalt (penetration (25°C, 100 g, 5 s) 70 (0.1 mm)) 60 parts, polyamide curing agent (amine value 250 mgKOH / g) 8 parts, 2-methyl imidazole 1 part, 0.8 part silane coupling agent KH-560.

[0058] ① According to the mass fraction, 60 parts of road petroleum asphalt was heated to 140°C to melt, and 40 parts of bisphenol A epoxy resin and 0.8 parts of KH-560 were added, and stirred at 800 rpm for 30 minutes; ② 6 parts of the above epoxy-capped phosphorus-silicon flame retardant was added, and dispersed at 150°C and 1200 rpm for 1 hour; ③ The temperature was lowered to 120°C, 8 parts of polyamide curing agent and 1 part of 2-methyl imidazole accelerator were added, and stirred at 3000 rpm for 1 min, then 1300 parts of AC-13 mineral aggregate basalt at 180°C was added, and stirred at 120°C for 5 min to obtain the epoxy asphalt concrete.

[0059] The Marshall compaction instrument was used to form the test piece (Φ101.6 mm×63.5 mm), and the test piece was cured at 120°C for 4 hours and cooled to room temperature for standby.

[0060] Example 3 1. Preparation of reactive flame retardant for epoxy asphalt (1) Hydrolysis reaction: 1 mol of silane coupling agent (KH-590, 3-mercaptopropyl trimethoxysilane) and 3 mol of deionized water were added to a 500 mL four-necked flask, and the pH was adjusted to 3.2 with dilute hydrochloric acid under nitrogen protection, stirred at 300 rpm, and reacted at 60°C for 2 hours. Hydrolysis generated liquid trihydroxysilane intermediates and ethanol, and the generated ethanol and deionized water in the beaker were removed by distillation to obtain the trihydroxysilane intermediates.

[0061] (2) Phosphorylation reaction: 1.2 mol of dimethyl methylphosphonate (DMMP) and 0.5% of the total mass of the raw material DBTDL were added to the liquid trihydroxysilane intermediates obtained in step (1), and the temperature was raised to 70°C for 4 hours.

[0062] (3) Epoxy capping reaction: 1.5 mol of epoxy chloropropane was slowly added to the product obtained in step (2), and reacted at 80°C for 6 hours. During the reaction, the pH was adjusted to 7.2 with triethylamine, and the byproduct hydrogen chloride gas was eliminated. Attention should be paid to collect the tail gas. After the reaction was completed, the product (epoxy-capped phosphorus-silicon flame retardant) was obtained by distillation under reduced pressure, which was a light yellow transparent product, i.e. the epoxy asphalt reactive phosphorus-silicon flame retardant, with a phosphorus content of 8.9%, a silicon content of 8.0%, and an epoxy value of 0.28 eq / 100g.

[0063] 2. Preparation of epoxy asphalt concrete: Bisphenol A type epoxy resin (epoxy value 0.4 eq / 100g) 40 parts, road petroleum asphalt (penetration (25°C, 100g, 5s) 70 (0.1mm)) 60 parts, polyamide curing agent (amine value 250 mgKOH / g) 8 parts, 2-methyl imidazole accelerator 1 part, 0.8 part silane coupling agent KH-560.

[0064] ① According to the mass fraction, 60 parts of road petroleum asphalt was heated to 140°C to melt, 40 parts of bisphenol A epoxy resin and 0.8 parts of KH-560 were added, and stirred at 800 rpm for 30 minutes; ② 6 parts of the above epoxy-capped phosphorus-silicon flame retardant was added, and dispersed at 150°C and 1200 rpm for 1 hour; ③ The temperature was lowered to 120°C, 8 parts of polyamide curing agent and 1 part of 2-methyl imidazole accelerator were added, and stirred at 3000 rpm for 1 min, then 1300 parts of AC-13 mineral aggregate basalt at 180°C was added, and stirred at 120°C for 5 min to obtain the epoxy asphalt concrete.

[0065] The Marshall compaction instrument was used to form the test piece (Φ101.6mm×63.5mm), which was cured at 120°C for 4h and cooled to room temperature for standby.

[0066] Example 4 1. Preparation of reactive flame retardant for epoxy asphalt (1) Hydrolysis reaction: 1 mol of silane coupling agent (KH-570, 3-trimethoxysilyl methyl propyl methacrylate) and 3 mol of deionized water were added into a 500 mL four-necked flask, and the pH was adjusted to 3.2 with dilute hydrochloric acid under nitrogen protection, and stirred at 300 rpm, and reacted at 50°C for 2 hours to hydrolyze to generate a liquid trihydroxysilane intermediate and ethanol. The generated ethanol and deionized water in the beaker were removed by distillation to obtain the trihydroxysilane intermediate.

[0067] (2) Phosphorylation reaction: 1.2 mol of dimethyl ethyl phosphonate (DMEP) and 0.5% of DBTDL based on the total mass of the raw materials were added to the liquid trihydroxysilane intermediate obtained in step (1), and the temperature was raised to 60°C and reacted for 4 hours.

[0068] (3) Epoxy capping reaction: 1.5 mol of epichlorohydrin was slowly added dropwise to the product obtained in step (2), and reacted at 80°C for 6 hours. During the reaction, triethylamine was used to adjust the pH to 7.2, and the byproduct hydrogen chloride gas was eliminated. Attention should be paid to collect the tail gas. After the reaction was completed, the product (epoxy-capped phosphorus-silicon flame retardant) was obtained by distillation under reduced pressure, which was a light yellow transparent product, which was an epoxy asphalt reactive phosphorus-silicon flame retardant. The phosphorus content was 7.5%, the silicon content was 6.8%, and the epoxy value was 0.25 eq / 100 g.

[0069] 2. Preparation of epoxy asphalt concrete: 40 parts of bisphenol A type epoxy resin (epoxy value 0.4 eq / 100 g), 60 parts of road petroleum asphalt (penetration (25°C, 100 g, 5 s) 70 (0.1 mm)), 8 parts of polyamide curing agent (amine value 250 mgKOH / g), 1 part of 2-methyl imidazole, and 0.8 part of silane coupling agent KH-560.

[0070] ① According to the mass fraction, 60 parts of road petroleum asphalt was heated to 140°C to melt, 40 parts of bisphenol A epoxy resin and 0.8 parts of KH-560 were added, and stirred at 3000 rpm for 30 minutes; ② 10 parts of the above epoxy-capped phosphorus-silicon flame retardant was added, and dispersed at 150°C and 1200 rpm for 1 hour; ③ The temperature was lowered to 120°C, 8 parts of polyamide curing agent and 1 part of 2-methyl imidazole accelerator were added, and stirred at 3000 rpm for 1 min, then 1300 parts of AC-13 mineral aggregate basalt at 180°C was added, and stirred at 120°C for 5 min to obtain the epoxy asphalt concrete.

[0071] The Marshall compaction instrument was used to form the test piece (Φ101.6 mm x 63.5 mm), which was cured at 120°C for 4h and cooled to room temperature for standby.

[0072] Comparative Example 1 An epoxy asphalt concrete is composed of the following raw materials in parts by weight: bisphenol A type epoxy resin (epoxy value 0.4 eq / 100g) 40 parts, road petroleum asphalt (penetration (25℃, 100g, 5s) 70 (0.1mm)) 60 parts, decabromodiphenyl ethane 6 parts, polyamide curing agent (amine value 250mgKOH / g) 8 parts, 2-methyl imidazole 1 part, 0.8 parts of silane coupling agent KH-560 and AC-13 mineral aggregate basalt 1300 parts. The preparation method is the same as that of Example 1, except that the epoxy-capped phosphorus-silicon flame retardant is replaced by decabromodiphenyl ethane (conventional flame retardant).

[0073] Comparative Example 2 (1) Hydrolysis reaction: 1 mol of silane coupling agent (KH-560, 3-glycidyloxypropyl trimethoxysilane) and 3 mol of deionized water were added to a 500 mL four-necked flask, and the pH was adjusted to 3.2 with dilute hydrochloric acid under nitrogen protection, stirred at 300 rpm, and reacted at 40℃ for 2 hours. Hydrolysis generated liquid trihydroxysilane intermediates and ethanol, and the generated ethanol and deionized water in the beaker were removed by distillation to obtain the trihydroxysilane intermediates.

[0074] (2) Phosphorylation reaction: 1.2 mol of dimethyl methylphosphonate (DMMP) and 0.5% of the total mass of the raw materials of DBTDL were added to the liquid trihydroxysilane intermediates obtained in step (1), and the temperature was raised to 60℃ for 4 hours. The reaction product containing only the original epoxy group of KH-560 was obtained, with a phosphorus content of 10.7%, a silicon content of 9.7%, and an epoxy value of 0.28 eq / 100g.

[0075] Preparation of epoxy asphalt concrete: The preparation method is the same as that of Example 1, except that the epoxy-capped phosphorus-silicon flame retardant is replaced by the above flame retardant (reaction product containing only the original epoxy group of KH-560).

[0076] In order to describe the present application in more detail, 100 parts of epoxy asphalt were added with 6 parts of the epoxy-capped phosphorus-silicon flame retardant prepared in Examples 1-4 to prepare modified epoxy asphalt, and the performance of the modified epoxy asphalt was tested. At the same time, the conventional flame retardant decabromodiphenyl ethane was used as Comparative Example 1, and the flame retardant without epoxy encapsulation reaction was used as Comparative Example 2, and the limiting oxygen index test (NB / SH / T0815-2010), vertical burning test (GB / T2408), Cleveland open cup method (GB / T3536), smoke density box method (GB / T8627-2007), direct tensile method (ASTM D638-22) and other performance tests of the epoxy-capped phosphorus-silicon flame retardant modified epoxy asphalt were carried out, and the test results are shown in Table 3.

[0077] Table 3 Performance test results of flame-retardant modified epoxy asphalt

[0078] Compared with the conventional flame retardant of Comparative Example 1, the epoxy-terminated phosphorus-silicon flame retardants synthesized by using silane coupling agents KH-560, KH-570, KH-590 and alkyl phosphate DMMP, DMEP as raw materials in Example 1 to Example 4 respectively all show higher limiting oxygen index, and have higher vertical burning grade, especially by using alkyl phosphate DMMP for phosphorylation reaction, the synthesized epoxy-terminated phosphorus-silicon flame retardant has higher limiting oxygen index.

[0079] Compared with the phosphorus-silicon flame retardant without using epichlorohydrin packaging of Comparative Example 2, the epoxy-terminated phosphorus-silicon flame retardants with epichlorohydrin packaging in Example 1 to Example 4 all show higher limiting oxygen index. It is illustrated that compared with the existing flame retardant, the flame retardant effect of the epoxy-terminated phosphorus-silicon flame retardant prepared by the present application is better, and when it is used for preparing epoxy asphalt mixture such as epoxy asphalt concrete, the building material is more difficult to burn and has stronger combustion safety, and can be used as flame-retardant epoxy asphalt concrete and applied to tunnel, airport and other construction scenes.

[0080] The epoxy asphalt concrete prepared in Example 1 to Example 4 and Comparative Example 1 and Comparative Example 2 is respectively subjected to stripping test, Marshall stability test, rutting test, freeze-thaw splitting test, migration amount and other performance tests according to JTG3410-2025, and the test results are shown in Table 4 below.

[0081] Migration amount test: prepare a flame-retardant epoxy asphalt concrete test piece with a size of 5cmx5cmx2cm, age at 163℃ for 48h, then completely immerse the test piece in a certain volume of deionized water, immerse at 25℃ for 7 days, after the immersion is completed, detect the concentration of the flame retardant in the immersion liquid by using high performance liquid chromatography (HPLC), and calculate the migration amount of the flame retardant per unit area (unit: μg / m²).

[0082] Table 4 Performance test results of epoxy asphalt concrete

[0083] Compared with the epoxy asphalt concrete prepared by adding the conventional flame retardant of Comparative Example 1, the epoxy asphalt concrete prepared by adding the epoxy-terminated phosphorus-silicon flame retardant in Example 1 to Example 4 has higher freeze-thaw splitting strength ratio and lower migration amount. It is illustrated that the epoxy-terminated phosphorus-silicon flame retardant prepared according to the method can not only improve the flame retardant performance of the epoxy asphalt concrete, but also can enhance the mechanical properties of the epoxy asphalt concrete, and improve its road performance, and can be applied to application scenes with high requirements for the flame retardant effect, mechanical strength and use stability of building materials.

[0084] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An epoxy asphalt reactive phosphorus-silicon flame retardant, characterized by, The epoxy-capped phosphorus-silicon flame retardant comprises a phosphorus acyl group, a siloxane group and an epoxy group, and has a structure shown in the following general formula (I). ； In the formula, R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, or methacryloxy, and R2 is selected from methyl, ethyl, propyl, or hydroxyl.

2. The epoxy asphalt reactive phosphorus-silicon flame retardant according to claim 1, characterized in that, The phosphorus content is 7.2%-9.7%, the silicon content is 6.5%-8.8%, and the epoxy value is (0.23-0.50) eq / 100g.

3. The epoxy asphalt reactive phosphorus-silicon flame retardant according to claim 2, characterized in that, In the formula, R1 is selected from mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, or methacryloxy, and R2 is selected from methyl, ethyl, propyl, or hydroxyl.

4. The method for preparing the epoxy asphalt reactive phosphorus-silicon flame retardant according to claim 1, characterized in that, The method comprises the following steps: (1) Hydrolysis reaction: a silane coupling agent and deionized water are mixed in a molar ratio of 1:(3-5), the pH of the system is adjusted to 3-5, and the mixture is reacted at a temperature of 25-70°C under an inert atmosphere for 1-3 hours to obtain a liquid trihydroxysilane intermediate; the general formula of the silane coupling agent is [R1(CH2)3]Si(OCH3)3, and R1 is selected from amino, mercapto, 2-(methoxymethyl)oxiranyl, acryloxy, diaminoethyl, or methacryloxy; (2) Phosphorylation reaction: the liquid trihydroxysilane intermediate obtained in step (1) is added with alkyl phosphate in a molar amount of 1.0-1.5 times that of the silane coupling agent, a catalyst is added in an amount of 0.3%-0.8% of the total mass of the reactants, and the mixture is reacted at 60°C-100°C for 3-5 hours to obtain a reaction product; the general formula of the alkyl phosphate is R2P(=O)(OCH3)2, and R2 is methyl, ethyl, propyl, or hydroxyl; (3) Epoxy capping reaction: the reaction product obtained in step (2) is slowly added with epoxy chloropropane, the pH of the system is adjusted to 7-8, and the mixture is reacted at 70°C-90°C for 4-8 hours while removing the generated hydrogen chloride to obtain a light yellow transparent final product, i.e., an epoxy asphalt reactive phosphorus-silicon flame retardant.

5. The method of claim 4, wherein, In step (1), the silane coupling agent is selected from one or more of KH-540, KH-560, KH-570, KH-590, KH-792, and TMSPMA.

6. The method of claim 5, wherein, In step (2), the alkyl phosphate is selected from one or more of dimethyl methylphosphonate DMMP, dimethyl ethylphosphonate DMEP, and dimethyl propylphosphonate DPrMP; and the catalyst is selected from dibutyltin dilaurate, which is added in an amount of 0.3%-0.8% of the total mass of the silane coupling agent and the alkyl phosphate.

7. The method of claim 6, wherein, In step (3), the addition amount of the epoxy chloropropane is 1.2-1.8 times the molar amount of the silane coupling agent.

8. A flame-retardant modified epoxy bitumen, characterized in that, The method comprises the following steps:

9. A flame-retardant epoxy asphalt concrete, characterized by, The method comprises the following steps:

10. The fire-retardant epoxy asphalt concrete of claim 9, wherein, ​ 40-100 parts of asphalt base is heated to melt, 30-50 parts of bisphenol A epoxy resin and 0.3-1 part of silane coupling agent are added, and the mixture is stirred to form a mixed base; 5-15 parts of the epoxy asphalt reactive phosphorus-silicon flame retardant according to any one of claims 1 to 3 are added, and the temperature is raised to 130-160 DEG C and stirred uniformly; The temperature is lowered to 110-130 DEG C, a curing agent and an accelerator are added, and after stirring uniformly, 1000-1500 parts of mineral aggregate heated to 170-180 DEG C are added, and stirred at 110-130 DEG C for 5 min±5 s, and after curing, the flame-retardant epoxy asphalt concrete is obtained.

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