Single-component slow-curing flame-retardant smoke-suppression type polyurethane for road and preparation method of mixture containing single-component slow-curing flame-retardant smoke-suppression type polyurethane

Abstract

The invention provides a single-component slow-curing flame-retardant smoke-suppression polyurethane for roads and a preparation method of a mixture containing the same. The mixture comprises the following raw materials: a stone combination, a single-component polyurethane adhesive, a curing agent and an inorganic flame retardant, and a pore-forming material is added into the single-component polyurethane adhesive. According to the method, the smoke density is reduced without the help of a large number of smoke suppression materials, the size of an internal pore structure is freely adjusted and controlled from a polyurethane body structure, efficient smoke absorption is achieved, and the method has a good effect on tunnel environment application.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane road materials technology, specifically relating to a single-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane for road use and a method for preparing a mixture containing the same. Background Technology

[0002] Tunnel pavement is an important aspect of highway tunnel construction. Unlike conventional road surfaces, tunnels are enclosed environments with poor visibility, which places higher demands on tunnel pavement materials.

[0003] Currently, tunnel pavements are mainly constructed with asphalt concrete and cement concrete. Cement concrete pavements, with their thicker structural layers, offer high strength, but their unevenness significantly impacts driving comfort. Cement concrete also has poor skid resistance, seriously affecting tunnel safety. Furthermore, cement concrete has numerous joints that are easily damaged, leading to high maintenance costs. To address the issue of flame retardancy in tunnels, flame-retardant modified asphalt is increasingly used. While asphalt concrete pavements offer high skid resistance, a smooth surface, and good driving comfort, the black asphalt surface results in poor lighting inside the tunnel. Moreover, both conventional modified flame-retardant asphalt and cold-mixed flame-retardant asphalt experience high temperatures during construction, exceeding 100°C. The enclosed tunnel environment makes heat dissipation difficult. Simultaneously, the high temperatures cause asphalt to release carcinogens such as dioxins, and the large amounts of smoke and dust generated during asphalt construction pose a serious danger to the lives of construction workers in the confined tunnel environment.

[0004] CN120157385A provides a flame-retardant polyurethane adhesive for tunnels that meets the flame-retardant standards for tunnel paving. However, its flame retardant cost is relatively high, and it focuses more on flame-retardant related processes, with less explanation of the adhesive preparation. Moreover, the actual Marshall stability performance of the prepared mixture specimens is relatively poor.

[0005] Furthermore, the core issue of high smoke density in polyurethane adhesives still relies on adding large quantities of smoke suppressants, which offers limited smoke suppression and lacks lightweight characteristics. Excessive addition of smoke suppressants also leads to a significant decrease in the mechanical properties of polyurethane adhesives. Therefore, developing a tunnel material with excellent pavement performance, highly efficient smoke suppression properties in its structural features, and meeting the requirements for flame retardancy and smoke suppression is of great significance in addressing the problems of smoke and dust and high-temperature construction during asphalt tunnel construction. Summary of the Invention

[0006] To address the problems of high smoke density in polyurethane adhesives, the large amount of smoke suppressants required by traditional methods, limited smoke suppression effectiveness, poor weight reduction, and serious impact on adhesive performance, this invention provides a single-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane adhesive and a method for preparing its mixture. This method eliminates the need for large amounts of smoke suppressant materials to reduce smoke density, and allows for free control of the internal pore size from the polyurethane's bulk structure, achieving highly efficient smoke absorption. This is of great significance for applications in tunnel environments.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A one-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane compound, wherein the compound comprises the following raw materials in parts by weight:

[0009] 100 portions of stone materials

[0010] 5-7 parts of one-component polyurethane adhesive,

[0011] Hardener 0.5-5 parts,

[0012] 1-3 parts of inorganic flame retardant;

[0013] The single-component polyurethane adhesive contains a pore-forming material, preferably pore-forming template particles.

[0014] The polyurethane adhesive provided by this invention innovatively introduces hydrazine p-toluenesulfonate, a pore-forming material. Hydrazine p-toluenesulfonate exhibits a "dispersion-forming-post-decomposition" characteristic, and under normal construction conditions, it has no impact on the performance of the polyurethane adhesive itself or on the pavement pore structure. In the event of a fire, the hydrazine p-toluenesulfonate particles rapidly decompose, quickly and directionally constructing a microporous-mesoporous composite structure within the adhesive. Furthermore, through formulation optimization, the pore size and pore diameter distribution can be precisely adjusted to determine the optimal pore structure parameters, thereby controlling the delayed transport and rapid adsorption of smoke within the polyurethane.

[0015] In one embodiment of the present invention, the one-component polyurethane adhesive is obtained by mixing a prepolymer of isocyanate and polyol, a plasticizer, a flame retardant and a pore-forming material.

[0016] In one embodiment of the present invention, the NCO content of the one-component polyurethane adhesive is 10%-18%.

[0017] In one embodiment of the invention, the isocyanate of the prepolymer comprises an aromatic and / or aliphatic isocyanate, preferably one or more of HT-300, MDI-100, MDI-50, and PM-200.

[0018] In one embodiment of the present invention, the polyol of the prepolymer comprises polyether polyol and / or vegetable oil polyol, preferably polyether polyol and vegetable oil polyol are used in combination; preferably, the polyol has a functionality of 2-3 and an average molecular weight of 1000-5000 g / mol; preferably, the prepolymer accounts for 66%-88% of the mass of the single-component polyurethane adhesive.

[0019] In one embodiment of the present invention, the plasticizer comprises chlorinated alkane plasticizer and vegetable oil-based plasticizer, preferably one or more of 52# chlorinated paraffin, 42# chlorinated paraffin, and soybean oil; preferably, the plasticizer accounts for 0%-10% of the weight of the one-component polyurethane adhesive.

[0020] In one embodiment of the present invention, the flame retardant is a liquid flame retardant, preferably one or more of toluene diphenyl phosphate (CDP), trichloropropyl phosphate (TCPP), and isopropylbenzene diphenyl phosphate (IPPP); preferably, the amount of flame retardant is 10%-20% of the weight of the single-component polyurethane adhesive.

[0021] In one embodiment of the present invention, the pore-forming template particles comprise hydrazine p-toluenesulfonate; preferably, the particle size range of the pore-forming template particles is 10 nm-800 μm, more preferably one or more of 20-500 nm, 20-50 μm and 100-500 μm; preferably, the pore-forming template particles account for 2%-4% of the weight of the one-component polyurethane adhesive.

[0022] In one embodiment of the invention, the stone composition comprises one or more of limestone, basalt, and granite.

[0023] In one embodiment of the invention, the curing agent comprises water.

[0024] In one embodiment of the present invention, the inorganic flame retardant is an inorganic salt and / or an inorganic base, preferably comprising one or more of zinc borate, aluminum hydroxide, and magnesium hydroxide.

[0025] Another objective of this invention is to provide a method for preparing a single-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane mixture.

[0026] A method for preparing a single-component slow-curing flame-retardant and smoke-suppressing polyurethane compound, wherein the compound is the aforementioned compound, and the preparation method comprises the following steps:

[0027] S1: Isocyanate and polyol prepolymers are used to obtain NCO-terminated prepolymers, which are then mixed with plasticizers, flame retardants, and pore-forming materials to obtain a one-component polyurethane adhesive.

[0028] S2: A mixture and dispersion of a single-component polyurethane adhesive and an inorganic flame retardant;

[0029] S3: Combined drying and cooling of stone materials;

[0030] S4: Mix the stone mixture with the mixture of S2 and stir to obtain a polyurethane mixture.

[0031] In one embodiment of the present invention, the prepolymerization temperature in S1 is 80-95°C and the time is 2.5-3 hours.

[0032] In one embodiment of the present invention, the stone combination in S3 is dried at 100-150°C for 8-15 hours and then cooled to 40-70°C.

[0033] In one embodiment of the present invention, the stone combination in S4 is mixed with the mixture in S2 for 40-90 seconds.

[0034] Another object of the present invention is to provide an application of a polyurethane compound.

[0035] An application of a polyurethane mixture, wherein the mixture is the mixture described above, or a mixture prepared by the above preparation method, wherein the mixture is used as a single-component slow-curing flame-retardant and smoke-suppressing polyurethane mixture, preferably for tunnel pavement paving.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) By using hydrazine p-toluenesulfonate as a pore-forming material, an optimal pore structure is constructed inside the polyurethane adhesive to achieve efficient smoke absorption. Compared with traditional smoke suppressants, the smoke suppression effect is improved by 10%-20%. At the same time, the high open porosity reduces the thermal conductivity of the material, and heat is quickly dissipated through the pores during combustion, reducing the surface temperature of the substrate by 80-120°C and slowing down the pyrolysis rate of the polyurethane adhesive.

[0038] (2) Compared to methods that add a large amount of smoke suppressant, this invention achieves improved smoke suppression through a porous structure, resulting in lightweight properties from the perspective of the adhesive's bulk material, while avoiding the impact of a large amount of smoke suppressant on the mechanical properties of the adhesive. Other features and advantages of this invention will be described in detail in the following specific embodiments. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, but the content of the present invention is not limited to the following embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0040] The materials and equipment involved in the following specific embodiments of the present invention are as follows:

[0041] (1) Stone composition: Limestone and basalt stone from Yantai Taihua Road and Bridge Company that meet the standards of "JTG E42-2005 Highway Engineering Aggregate Test Procedure" are selected. The sieve passing rates of the stone composition are as follows: When the sieve openings are 16, 13.2, 9.5, 4.75, 2.36, 1.18, 0.6, 0.3, 0.15 and 0.075 mm, the corresponding passing rates are 100, 90-100, 68-85, 38-68, 24-50, 15-38, 10-28, 7-20, 5-15 and 4-8 respectively.

[0042] (2) Single-component polyurethane adhesive: prepared by mixing a prepolymer of isocyanate and polyol, a plasticizer, a flame retardant, and a pore-forming material, wherein:

[0043] The isocyanates selected are Wanhua Chemical's PM-200, MDI-50, MDI-100, and HT-300.

[0044] The polyether polyols selected were WANOL C2020 (functionality 2, molecular weight 2000 g / mol) and WANOLF3056D (functionality 3, molecular weight 3000 g / mol) from Wanhua Chemical; the vegetable oil polyols selected were castor oil from Fucheng Huanyu Oil Co., Ltd. (acidity ≤2 mg KOH / g, moisture ≤0.1%, hydroxyl value 163, average functionality 2.7, molecular weight 933 g / mol).

[0045] The chlorinated alkane plasticizer selected is Chuangyi New Materials' 42# chlorinated paraffin (density 1.13-1.17 g / cm³). 3 (Purity > 99%), the vegetable oil-based plasticizer used is soybean oil from Yantai Yihai (density 0.917 g / cm³). 3 Food-grade soybean oil).

[0046] The flame retardants selected are IPPP from Fengtong Chemical (viscosity 50-100 mPa·s at 25℃, purity ≥90%) and CDP from Shandong Ruixing Flame Retardant Technology Co., Ltd. (density 1.19-1.21 g / cm³). 3 Acid value ≤ 0.1 mg KOH / g) and TCPP (viscosity 60-70 mPa·s at 25℃).

[0047] The pore-forming material used was hydrazine p-toluenesulfonate (TSH) from Shanghai Aladdin Biochemical Technology Co., Ltd. (analytical grade: 98% purity).

[0048] (3) Tap water is used as the curing agent.

[0049] (4) The inorganic flame retardants selected are aluminum hydroxide (10000μm, moisture 0.122%), magnesium hydroxide (chemically pure, 1000μm, moisture 0.116%) and zinc borate (1000μm, moisture 0.095%) from Jinan Jinyingtai Chemical Co., Ltd.

[0050] (5) Equipment Information:

[0051] Electronic universal testing machine, Shimadzu, AGS-X-10kN;

[0052] Fully automatic mixing machine, Shanghai Changji, SYD-F02-20;

[0053] Marshall compaction apparatus, Shanghai Changji, SYD-0702A;

[0054] Constant temperature and humidity chamber, High-speed rail testing instrument company, GT-7005-A2L;

[0055] Fully automatic mixture pressure testing machine, Shanghai Changji, SYD-0730A;

[0056] The Marshall stability and splitting strength test methods shall be performed in accordance with T0709 and T0716 of the "JTG E20-2011 Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering".

[0057] The tensile strength and elongation at break test methods refer to GB / T 528-2009 standard, with a tensile speed of 200 mm / min.

[0058] Viscosity testing was performed in accordance with GB / T 2794-2022 standard.

[0059] Smoke density testing was conducted in accordance with GB / T 8627-2007 standard.

[0060] The oxygen index test shall be conducted in accordance with the NB / SH / T 0815-2010 standard.

[0061] Example 1

[0062] 1. Preparation of one-component polyurethane adhesive:

[0063] 260g of isocyanate MDI-50 and 240g of PM-200 were placed in a three-necked flask, followed by 85g of MDI-100. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 265g of polyether polyol C2020 was added, and the reaction was allowed to proceed for 3 hours. After the reaction was complete, the adhesive was cooled to 50℃, and 110g of TCPP flame retardant was added. Subsequently, 10g of TSH particles (20-500nm), 20g of TSH particles (20-50μm), and 10g of TSH particles (100-500μm) were added and mixed and dispersed evenly to obtain a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 1 with an NCO content of 17.97%.

[0064] 2. Preparation of polyurethane martensitic specimens:

[0065] 1) Place the basalt stone material assembly in a forced-air drying oven at 150℃ to dry and remove water for 15 hours. After the stone material is dehydrated, keep the oven at a constant temperature of 40℃ for later use.

[0066] 2) Polyurethane adhesive 1 and aluminum hydroxide flame retardant are mixed at a mass ratio of 8:2 and dispersed evenly in a homogenizer to prepare a mixed flame retardant adhesive;

[0067] 3) Preheat the mixing pot to 40°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 675g of mixed flame-retardant polyurethane adhesive and mix for 90 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 40°C oven and continue to keep it at a constant temperature for 2 hours.

[0068] 4) Ordinary tap water is used as the curing agent;

[0069] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 30g of curing agent is evenly sprayed on the surface, and then placed in an environment of 40℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0070] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0071] Example 2

[0072] 1. Preparation of one-component polyurethane adhesive:

[0073] 250g of isocyanate MDI-50, 70g of PM-200, and 110g of HT-300 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 95℃, 240g of polyether polyol C2020 was added, and the reaction was allowed to proceed for 2.5 hours. After the reaction was complete, the adhesive was cooled to 50℃, and 90g of soybean oil and 200g of CDP flame retardant were added. Subsequently, 10g of TSH particles (20-500nm), 20g of TSH particles (20-50μm), and 10g of TSH particles (100-500μm) were added. After mixing and dispersing evenly, a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 2 was obtained, with an NCO content of 11.78%.

[0074] 2. Preparation of polyurethane martensitic specimens:

[0075] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 70℃ for later use.

[0076] 2) Polyurethane adhesive 2, aluminum hydroxide flame retardant, and zinc borate flame retardant are mixed in a mass ratio of 7:1.5:1.5, and dispersed evenly in a homogenizer to prepare a mixed flame retardant adhesive;

[0077] 3) Preheat the mixing pot to 70°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 771g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 40 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 70°C oven and continue to keep it at a constant temperature for 2 hours.

[0078] 4) Ordinary tap water is used as the curing agent;

[0079] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 50g of curing agent is evenly sprayed on the surface, and then placed in an environment of 70℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0080] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0081] Example 3

[0082] 1. Preparation of one-component polyurethane adhesive:

[0083] 270g of isocyanate MDI-50 and 150g of PM-200 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 270g of polyether polyol C2020 and 70g of F3056D were added, and the mixture was reacted for 3 hours. After the reaction was completed, the adhesive was cooled to 50℃, and 100g of Chuangyi 42# chlorinated paraffin and 100g of TCPP flame retardant were added. Then, 40g of TSH particles (20-50μm) were added, and the mixture was mixed and dispersed evenly to obtain a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 3 with an NCO content of 12.32%.

[0084] 2. Preparation of polyurethane martensitic specimens:

[0085] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 50℃ for later use.

[0086] 2) Polyurethane adhesive 3 and aluminum hydroxide flame retardant 7 are mixed in a mass ratio of 3, and dispersed evenly in a homogenizer to prepare a mixed flame retardant adhesive;

[0087] 3) Preheat the mixing pot to 50°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 1,000g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 70 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 50°C oven and continue to keep it at a constant temperature for 2 hours.

[0088] 4) Ordinary tap water is used as the curing agent;

[0089] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 10g of curing agent is evenly sprayed on the surface, and then placed in an environment of 50℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0090] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0091] Example 4

[0092] 1. Preparation of one-component polyurethane adhesive:

[0093] 230g of isocyanate MDI-50 and 160g of PM-200 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 300g of polyether polyol C2020 and 110g of castor oil were added, and the mixture was reacted for 3 hours. After the reaction was completed, the adhesive was cooled to 50℃, and 160g of IPPP flame retardant was added. Then, 10g of TSH particles (20-500nm), 20g of TSH particles (20-50μm), and 10g of TSH particles (100-500μm) were added. After mixing and dispersing evenly, a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 4 was obtained with an NCO content of 10.12%.

[0094] 2. Preparation of polyurethane martensitic specimens:

[0095] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 50℃ for later use.

[0096] 2) Polyurethane adhesive 4 and aluminum hydroxide flame retardant 7.5:2.5 were mixed and dispersed evenly in a homogenizer to prepare a mixed flame retardant adhesive;

[0097] 3) Preheat the mixing pot to 50°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 720g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 90 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 50°C oven and continue to keep it at a constant temperature for 2 hours.

[0098] 4) Ordinary tap water is used as the curing agent;

[0099] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 10g of curing agent is evenly sprayed on the surface, and then placed in an environment of 50℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0100] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0101] Example 5

[0102] 1. Preparation of one-component polyurethane adhesive:

[0103] 230g of isocyanate MDI-50 and 160g of PM-200 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 300g of polyether polyol C2020 and 110g of castor oil were added, and the mixture was reacted for 3 hours. After the reaction was completed, the adhesive was cooled to 50℃, and 160g of IPPP flame retardant was added. Then, 20g of TSH particles (20-500nm), 10g of TSH particles (20-50μm), and 10g of TSH particles (100-500μm) were added. After mixing and dispersing evenly, a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 5 was obtained with an NCO content of 10.12%.

[0104] 2. Preparation of polyurethane martensitic specimens:

[0105] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 50℃ for later use.

[0106] 2) A mixed flame-retardant adhesive was prepared by mixing polyurethane adhesive 5 and aluminum hydroxide flame retardant 7.5:2.5 by mass and dispersing them evenly in a homogenizer.

[0107] 3) Preheat the mixing pot to 50°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 720g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 90 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 50°C oven and continue to keep it at a constant temperature for 2 hours.

[0108] 4) Ordinary tap water is used as the curing agent;

[0109] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 10g of curing agent is evenly sprayed on the surface, and then placed in an environment of 50℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0110] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0111] Example 6

[0112] 1. Preparation of one-component polyurethane adhesive:

[0113] 230g of isocyanate MDI-50 and 160g of PM-200 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 300g of polyether polyol C2020 and 110g of castor oil were added, and the mixture was reacted for 3 hours. After the reaction was completed, the adhesive was cooled to 50℃, and 160g of IPPP flame retardant was added. Then, 10g of TSH particles (20-500nm), 10g of TSH particles (20-50μm), and 20g of TSH particles (100-500μm) were added. After mixing and dispersing evenly, a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 6 was obtained with an NCO content of 10.12%.

[0114] 2. Preparation of polyurethane martensitic specimens:

[0115] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 50℃ for later use.

[0116] 2) Polyurethane adhesive 6 and aluminum hydroxide flame retardant 7.5:2.5 were mixed and dispersed evenly in a homogenizer to prepare a mixed flame retardant adhesive;

[0117] 3) Preheat the mixing pot to 50°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 720g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 90 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 50°C oven and continue to keep it at a constant temperature for 2 hours.

[0118] 4) Ordinary tap water is used as the curing agent;

[0119] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 10g of curing agent is evenly sprayed on the surface, and then placed in an environment of 50℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0120] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0121] Example 7

[0122] 1. Preparation of one-component polyurethane adhesive:

[0123] 230g of isocyanate MDI-50 and 160g of PM-200 were placed in a three-necked flask. The flask was then placed in an oil bath and heated with stirring until homogeneous. After the temperature reached 80℃, 300g of polyether polyol C2020 and 110g of castor oil were added, and the mixture was reacted for 3 hours. After the reaction was completed, the adhesive was cooled to 50℃, and 20g of soybean oil and 160g of IPPP flame retardant were added. Then, 5g of TSH particles (20-500nm), 10g of TSH particles (20-50μm), and 5g of TSH particles (100-500μm) were added. After mixing and dispersing evenly, a single-component slow-curing flame-retardant and smoke-suppressing polyurethane adhesive 7 was obtained with an NCO content of 10.12%.

[0124] 2. Preparation of polyurethane martensitic specimens:

[0125] 1) Place the limestone aggregate in a forced-air drying oven at 105℃ to dry and remove moisture for 10 hours. After the aggregate is dehydrated, keep the oven at a constant temperature of 50℃ for later use.

[0126] 2) A mixed flame-retardant adhesive was prepared by mixing polyurethane adhesive 7 and aluminum hydroxide flame retardant 7.5:2.5 by mass and dispersing them evenly in a homogenizer.

[0127] 3) Preheat the mixing pot to 50°C. Take 10,000g of cooled stone material and place it in the mixing pot. Add 720g of mixed flame-retardant polyurethane adhesive according to the formula ratio. Mix for 90 seconds to obtain the required polyurethane mixture. Place the polyurethane mixture in a 50°C oven and continue to keep it at a constant temperature for 2 hours.

[0128] 4) Ordinary tap water is used as the curing agent;

[0129] 5) After the constant temperature is completed, Marshall specimens are prepared in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011). During the specimen preparation process, 10g of curing agent is evenly sprayed on the surface, and then placed in an environment of 50℃ for 20min. Marshall specimens are prepared using a Marshall compactor with a diameter of 101.6mm and a thickness of 63.5mm.

[0130] 6) After the specimens are prepared, they are stored at room temperature for 5 days to test their Marshall stability and splitting strength.

[0131] Comparative Example 1

[0132] 1. Preparation of one-component polyurethane adhesive:

[0133] The preparation method is the same as in Example 4, except that 40g of soybean oil and 160g of IPPP flame retardant are used, and TSH particles are not used.

[0134] 2. Preparation of polyurethane martensitic specimens:

[0135] Similar to Example 4, the adhesive of Comparative Example 1 was used.

[0136] The adhesives prepared in Examples 1-7 and Comparative Example 1 were laid in films and cured for mechanical property and viscosity testing. The mechanical property test parameters were tensile strength and elongation at break; the viscosity parameter was the adhesive viscosity at 25°C. Mixture specimens were prepared according to the examples and comparative examples, and their stability and splitting tensile strength were tested after curing for a period of time.

[0137] Examples 1-7 are mixed flame-retardant adhesives containing three different TSH particle sizes, differing only in the adhesive and process formulation, as well as the proportion of each TSH particle size. Unlike the examples, Comparative Example 1 does not contain TSH particles.

[0138] The results of the adhesive performance test are shown in Table 1.

[0139] Table 1. Adhesive performance test results

[0140]

[0141] In summary, Examples 1-7 provide adhesive performance parameters for different types of flame retardants, different adhesive formulations, and different TSH particle combination ratios. It can be seen that the single-component adhesive exhibits excellent tensile strength and elongation at break. Simultaneously, it meets the oxygen index and smoke density requirements for tunnel construction (smoke density level ≤ 75, oxygen index ≥ 23).

[0142] As can be seen from Comparative Example 1, when the adhesive system does not contain TSH pore-forming particles, the smoke density level after combustion is high and does not meet the standard.

[0143] As can be seen from Examples 4-7, when the adhesive system contains three different types of porous structures simultaneously, the smoke density value of the adhesive is significantly reduced, and the more porous structures there are, the lower the smoke density value. Furthermore, when the adhesive structure contains a large number of 20-50 μm structures, its smoke adsorption capacity is significantly enhanced.

[0144] In summary, single-component polyurethane adhesives containing TSH pore-forming particles not only possess excellent mechanical properties and ideal surface drying time, but their core advantage lies in the precise controllability of their pore structure: through high-temperature induction of pore-forming particle decomposition, a microporous-mesoporous composite structure can be directionally constructed, and the pore size, pore diameter distribution, and porosity can be finely adjusted through formulation optimization, thereby precisely finding the optimal pore structure parameters suitable for smoke adsorption. This characteristic enables the adhesive to maximize the capture of smoke particles generated by combustion, significantly reduce smoke density, and achieve optimal smoke adsorption effect. This functional design is of key significance for the application of polyurethane mixtures in tunnel environments, providing core technical support for improving safety protection performance in tunnel fire scenarios.

[0145] The performance test results of the mixture are shown in Table 2. The Martens stability and splitting tensile strength of the Martens specimens after complete curing were tested according to the methods T0709 and T0716 in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering (JTG E20-2011)". As can be seen from the table, the addition of flame retardant did not have a serious impact on the mechanical properties of the adhesive. The stability and splitting tensile strength of the mixture were significantly higher than those of the asphalt mixture.

[0146] Table 2 Results of Mixture Performance Tests

[0147]

[0148] The applicant declares that this invention illustrates the single-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane adhesive for road paving and the polyurethane mixture containing the same through the above embodiments, but this invention is not limited to the above embodiments. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. A single-component, slow-curing, flame-retardant, and smoke-suppressing polyurethane compound, characterized in that, The mixture comprises the following raw materials in parts by weight: 100 portions of stone materials 5-7 parts of one-component polyurethane adhesive, Hardener 0.5-5 parts, 1-3 parts of inorganic flame retardant; The single-component polyurethane adhesive contains a pore-forming material, preferably pore-forming template particles.

2. The mixture according to claim 1, characterized in that, The single-component polyurethane adhesive is obtained by mixing a prepolymer of isocyanate and polyol, a plasticizer, a flame retardant, and a pore-forming material. And / or, the NCO content of the single-component polyurethane adhesive is 10%-18%; And / or, the isocyanate of the prepolymer comprises aromatic and / or aliphatic isocyanates, preferably one or more of HT-300, MDI-100, MDI-50, and PM-200; And / or, the polyol of the prepolymer comprises polyether polyol and / or vegetable oil polyol, preferably polyether polyol and vegetable oil polyol are used in combination; Preferably, the polyol has a functionality of 2-3 and an average molecular weight of 900-5000 g / mol; Preferably, the prepolymer accounts for 66%-88% of the mass of the one-component polyurethane adhesive; And / or, the plasticizer comprises chlorinated alkane plasticizers and vegetable oil-based plasticizers, preferably one or more of 52# chlorinated paraffin, 42# chlorinated paraffin, and soybean oil; Preferably, the plasticizer accounts for 0%-10% of the weight of the one-component polyurethane adhesive; And / or, the flame retardant is a liquid flame retardant, preferably one or more of toluene diphenyl phosphate (CDP), trichloropropyl phosphate (TCPP), and isopropylbenzene diphenyl phosphate (IPPP); Preferably, the amount of flame retardant is 10%-20% of the weight of the one-component polyurethane adhesive; And / or, the pore-forming template particles contain hydrazine p-toluenesulfonate; Preferably, the particle size range of the pore-forming template particles is 10nm-800μm, and more preferably one or more of 20-500nm, 20-50μm and 100-500μm; Preferably, the pore-forming template particles account for 2%-4% of the weight of the single-component polyurethane adhesive.

3. The mixture according to claim 1 or 2, characterized in that, The stone composition includes one or more of limestone, basalt, and granite.

4. The mixture according to any one of claims 1-3, characterized in that, The curing agent contains water.

5. The mixture according to any one of claims 1-4, characterized in that, The inorganic flame retardant is an inorganic salt and / or inorganic alkali, preferably containing one or more of zinc borate, aluminum hydroxide, and magnesium hydroxide.

6. A method for preparing a single-component slow-curing flame-retardant and smoke-suppressing polyurethane mixture, wherein the mixture is the mixture according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: S1: Isocyanate and polyol prepolymers are used to obtain NCO-terminated prepolymers, which are then mixed with plasticizers, flame retardants, and pore-forming materials to obtain a one-component polyurethane adhesive. S2: A mixture and dispersion of a single-component polyurethane adhesive and an inorganic flame retardant; S3: Combined drying and cooling of stone materials; S4: Mix the stone mixture with the mixture of S2 and stir to obtain a polyurethane mixture.

7. The mixture according to claim 6, characterized in that, The prepolymerization temperature in S1 is 80-95℃, and the time is 2.5-3h; And / or, the stone assemblies in S3 are dried at 100-150℃ for 8-15 hours and then cooled to 40-70℃; And / or, the stone combination in S4 is mixed with the mixture in S2 for 40-90 seconds.

8. An application of a polyurethane mixture, wherein the mixture is the mixture according to any one of claims 1-5, or the mixture prepared by the preparation method according to claim 6 or 7, wherein the mixture is used as a single-component slow-curing flame-retardant and smoke-suppressing polyurethane mixture, preferably for tunnel pavement paving.

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