Underwater curing polyurethane sealant and preparation method thereof

Abstract

The invention relates to the technical field of underwater curing sealants, in particular to an underwater curing polyurethane sealant and a preparation method thereof. The underwater curing polyurethane sealant is prepared from glue, dioctyl terephthalate, a wetting dispersant, a water removal agent, a thixotropic agent, filler, magnesium fluoride, carbon black and an ultraviolet light absorber, wherein the glue is prepared from the following raw materials in parts by mass: polyoxyethylene polyoxypropyl glyceryl ether, polypropylene glycol, bio-based polyol, isocyanate propyl triethoxy silane, diphenylmethane diisocyanate, a drier, a coupling agent, a de-foaming agent, a diluent and a latent curing agent. The underwater curing polyurethane sealant disclosed by the invention not only can be rapidly cured underwater, but also can rapidly form a stable bonding interface after being cured underwater to effectively resist permeation of water molecules, so that the long-term sealing effect and the structural stability are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of underwater curable sealants, in particular to an underwater curable polyurethane sealant and a preparation method thereof. Background Art

[0002] In underwater engineering, the curing time and bonding strength of sealants are important indicators for evaluating their performance. The curing time and bonding strength of traditional underwater sealants, especially polyurethane sealants, are significantly affected by environmental factors. Although they show good adhesion and curing speed in a dry environment, in an underwater environment, due to the penetration and obstruction of water molecules, the curing time of polyurethane sealants tends to be prolonged and the bonding strength tends to decrease. Especially when the sealant is in a long-term immersion state, its bonding strength will further decrease, which may lead to sealing failure, making it difficult to meet the special needs of ships sailing at sea and underwater facility maintenance.

[0003] With the continuous development of marine engineering and underwater technology, the performance requirements for underwater sealants are getting higher and higher. Especially in the fields of shipbuilding, underwater pipeline laying, offshore platform construction, etc., a sealant material that can quickly solidify underwater and has high-strength bonding is needed. Summary of the invention

[0004] In order to shorten the curing time of polyurethane sealants under water and improve the bonding strength of polyurethane sealants under water, the present application provides an underwater curing polyurethane sealant and a preparation method thereof. The underwater curing polyurethane sealant of the present application can not only cure quickly under water, but also quickly form a stable bonding interface after curing under water, effectively resisting the penetration of water molecules, thereby ensuring a long-term sealing effect and structural stability.

[0005] In the first aspect, the present application provides an underwater curing polyurethane sealant that adopts the following technical solution: An underwater curing polyurethane sealant comprises the following components in percentage by mass: 28.41%-39.52% glue, 20%-25% dioctyl terephthalate, 0.1%-0.5% wetting dispersant, 1%-2% dewatering agent, 30%-40% thixotropic agent, 4%-6% filler, 1%-2% magnesium fluoride, 0.1%-1% carbon black, and 0.1%-0.3% ultraviolet absorber; The glue comprises the following raw materials in parts by weight: 9-10 parts of polyoxyethyl polyoxypropyl glyceryl ether, 12-15 parts of polypropylene glycol, 0.1-0.5 parts of bio-based polyols, 0.1-0.5 parts of isocyanatepropyl triethoxysilane, 0.1-0.2 parts of γ-glycidyloxypropyl trimethoxysilane, 3-5 parts of diphenylmethane diisocyanate, 0.01-0.02 parts of drying agent, 0.1-0.3 parts of defoaming agent, 3-6 parts of diluent, and 1-2 parts of latent curing agent.

[0006] In the above technical scheme, the present application significantly improves the flexibility and water resistance of the sealant by selecting dioctyl terephthalate as the plasticizer of the sealant; by introducing carbon black, magnesium fluoride and ultraviolet absorber, the weather resistance and anti-aging properties of the sealant are enhanced. In particular, the introduction of carbon black and magnesium fluoride can prompt the sealant to quickly form a stable bonding interface, maintain the high bonding strength of the sealant, and meet the special requirements of underwater engineering for sealants.

[0007] This application further selects polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol, bio-based polyols, and diphenylmethane diisocyanate as the main ingredients of the glue, and selects isocyanate propyl triethoxysilane and γ-glycidyloxypropyl trimethoxysilane as silane coupling agents, so that the glue has good curing performance and bonding strength underwater. Among them, polyoxyethyl polyoxypropyl glyceryl ether and polypropylene glycol are the main polyether polyols, providing good adhesion; and the introduction of bio-based polyols significantly enhances the flexibility and bonding strength of the glue; on this basis, diphenylmethane diisocyanate is further introduced to react with polyether polyols to form polyurethane, which further enhances the curing performance and bonding strength of the glue. At the same time, isocyanate propyl triethoxysilane can react with -OH, -NH 2 It can react with active functional groups such as -SH to synthesize new functional small molecules or hybrid functional polymers, giving the sealant and substrate better adhesion and wet adhesion. γ-Glycidyloxypropyltrimethoxysilane can further improve the bonding strength of the sealant in a humid environment.

[0008] Preferably, the glue further comprises 0.3-0.5 parts of a curing aid, wherein the curing aid is a mixture of trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether in a mass ratio of 1:(1-1.37).

[0009] In the above technical scheme, the present application selects trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether as curing aids, which can effectively promote the curing reaction of polyurethane, further shorten the curing time, and further improve the bonding strength after curing, so that the glue can react quickly in an underwater environment to form a stable cross-linking structure, thereby achieving better rapid curing and high bonding strength effects.

[0010] Preferably, the glue comprises the following raw materials in parts by weight: 9.43 parts of polyoxyethyl polyoxypropyl glyceryl ether, 13.72 parts of polypropylene glycol, 0.3 parts of bio-based polyol, 0.3 parts of isocyanate propyl triethoxysilane, 0.15 parts of γ-glycidyloxypropyl trimethoxysilane, 4.01 parts of diphenylmethane diisocyanate, 0.012 parts of drying agent, 0.2 parts of defoaming agent, 4.32 parts of diluent, 1.1 parts of latent curing agent, 0.37 parts of curing aid.

[0011] In the above technical scheme, the present application further optimizes the amount of each raw material of the glue, thereby ensuring that the glue forms a more uniform cross-linked network structure during the underwater curing process, effectively preventing the penetration of water molecules, and ensuring the long-term stability and reliability of the sealant.

[0012] Preferably, the method for preparing the glue comprises the following steps: Step s1: polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol and bio-based polyol are stirred and mixed according to the formula, and heated to 110-115° C. When the temperature reaches 110-115° C., vacuum negative pressure dehydration is performed, and when the moisture content of the dehydrated mixture is below 0.05%, heating is stopped and the temperature is lowered; Step s2: lower the temperature of the material obtained in step s1 to 80-85°C, slowly add isocyanatepropyltriethoxysilane and diphenylmethane diisocyanate in batches, and control the total addition time within 30 minutes. After the addition, keep the temperature at 80-85°C for 1.5-2 hours; Step s3: Cool the material obtained in step s2 to 65-70°C, then add the remaining raw materials, continue stirring for 30 minutes, and then cool the material to 55-60°C to obtain glue.

[0013] In the above technical solution, the present application ensures the stable synthesis of the polyurethane prepolymer by controlling the reaction temperature and time, while avoiding the occurrence of side reactions, thereby improving the bonding performance of the glue.

[0014] Preferably, the step s1 is to stir at a speed of 180-220 r / min and perform vacuum dehydration at a vacuum degree of -0.09 to -0.1 MPa.

[0015] In the above technical solution, the present application reduces the interference of water molecules on the polyurethane curing reaction by controlling the stirring speed and vacuum degree, thereby improving the quality of the final product.

[0016] Preferably, the underwater curing polyurethane sealant comprises the following components in percentage by mass: 33.912% glue, 22.028% dioctyl terephthalate, 0.33% wetting dispersant, 1.38% dewatering agent, 35.16% thixotropic agent, 5.16% filler, 1.32% magnesium fluoride, 0.5% carbon black, and 0.21% ultraviolet absorber.

[0017] In the above technical solution, the present application ensures that the sealant has a faster curing time and higher bonding strength in an underwater environment by further optimizing the amount of each raw material used in the sealant.

[0018] Preferably, the dehydrating agent is molecular sieve activated powder.

[0019] In the above technical solution, the molecular sieve activated powder has a high specific surface area, uniform pore size distribution and excellent chemical stability, which makes it have a strong selective adsorption capacity, can achieve deep drying and dehydration, and prevent the generation of bubbles in the sealant from the root. In addition, the molecular sieve activated powder can also increase the smoothness of the sealant and improve the uniformity, strength and other physical properties of the sealant material.

[0020] Preferably, the latent curing agent is latent curing agent WL-1031.

[0021] In the above technical solution, the latent curing agent WL-1031 is an imine compound, which has special chain extender and cross-linker functions. It can not only be used as a latent curing agent for moisture-curing polyurethane to further accelerate the surface drying time of the product, but also can be used as a defoaming agent to solve the bubbles produced during the construction process of the sealant.

[0022] Preferably, the thixotropic agent is thixotropic powder B50.

[0023] In the above technical solution, the thixotropic powder B50 has excellent dispersibility and a particle size of less than 0.07 μm, which can provide the sealant with better anti-sagging and anti-precipitation properties.

[0024] In a second aspect, the present application provides a method for preparing an underwater curing polyurethane sealant using the following technical solution: A method for preparing an underwater curing polyurethane sealant comprises the following steps: Step 1: Mix dioctyl terephthalate and wetting and dispersing agent according to the formula, and then slowly add plasticizer, wetting and dispersing agent, dehydrating agent, thixotropic agent, filler, magnesium fluoride, carbon black, and ultraviolet absorber. The total adding time is controlled within 30 minutes, and then slowly stir for 40 minutes; Step 2: Add glue to the material obtained in step 1, and then continue to stir evenly, then perform vacuum negative pressure degassing for 50-60 minutes, stop stirring, and obtain underwater curing polyurethane sealant.

[0025] Preferably, the step 1 is stirred at a speed of 60-80 r / min, the step 2 is stirred at a speed of 180-220 r / min, and the step 2 is firstly vacuum degassing at -0.06 to -0.07 MPa for 35-40 min, and then vacuum degassing at -0.095 to -0.09 MPa for 15-20 min.

[0026] In the above technical scheme, the present application ensures the uniform mixing and stable performance of the sealant through the above preparation method. The finally obtained underwater curing polyurethane sealant not only has excellent curing speed and bonding strength, but also has good weather resistance and anti-aging properties in underwater environment, meeting the special requirements of underwater engineering for sealants.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application introduces carbon black and magnesium fluoride into the sealant, which not only enhances the weather resistance and anti-aging properties of the sealant, but also enables the sealant to quickly form a stable bonding interface, maintain the high bonding strength of the sealant, and meet the special requirements of underwater engineering for sealants.

[0028] 2. This application not only improves the environmental performance of the sealant, but also significantly enhances the flexibility and bonding strength of the glue by further introducing bio-based polyols on the basis of polyether polyols.

[0029] 3. The present application adds a curing aid composed of trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether to the sealant, which can better shorten the curing time and further improve the bonding strength after curing, thereby achieving better rapid curing and high bonding strength effects. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Preparation Example 1 A glue for sealant comprises polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol, bio-based polyol, isocyanate propyl triethoxy silane, γ-glycidyl ether oxypropyl trimethoxy silane, diphenylmethane diisocyanate, a drying agent, a defoaming agent, a diluent and a latent curing agent.

[0032] Among them, polyoxyethyl polyoxypropyl glyceryl ether is polyether polyol ET34-08 of CNOOC Shell Petrochemical Co., Ltd.

[0033] The polypropylene glycol is polyether polyol ED56-200 produced by CNOOC Shell Petrochemical Co., Ltd.

[0034] Among them, the bio-based polyol is the vegetable oil polyol LC-140 produced by Guangzhou Longchi New Materials Technology Co., Ltd.

[0035] Among them, the isocyanate propyl triethoxysilane is the γ-isocyanate propyl triethoxysilane Siwin-AL32 of Nanjing Silicon Innovation Materials Co., Ltd.

[0036] Among them, γ-glycidyloxypropyltrimethoxysilane is the coupling agent KH-560 of Dongguan Chenfeng New Materials Co., Ltd.

[0037] Among them, diphenylmethane diisocyanate is MDI-50 produced by Wanhua Chemical Group Co., Ltd.

[0038] Among them, the drying agent is the drying agent T-12 produced by Guangzhou Longchi New Material Technology Co., Ltd.

[0039] Among them, the defoaming agent is the defoaming agent DF-682 of Guangzhou Deep Blue Polymer Co., Ltd.

[0040] Among them, the diluent is the diluent EGDA of Guangdong Hongchuan New Materials Co., Ltd.

[0041] Among them, the latent curing agent is the latent curing agent WL-1031 of Guangzhou Longchi New Material Technology Co., Ltd.

[0042] Wherein, the preparation method of glue comprises the following steps: Step s1: Add polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol and bio-based polyol into a three-necked flask according to the formula, start stirring and stir at a speed of 200 r / min, turn on the electric furnace and heat to 110°C. When the temperature reaches 110°C, turn on the vacuum pump, and draw vacuum negative pressure dehydration at a vacuum degree of -0.1 MPa. When the moisture content of the dehydrated mixture is below 0.05%, stop heating and cool down.

[0043] Step s2: The temperature of the material obtained in step s1 is lowered to 80°C, and isocyanatepropyltriethoxysilane and diphenylmethane diisocyanate are slowly added in batches. The total addition time is controlled within 30 minutes. After the addition is completed, the reaction is kept at 80°C for 2 hours.

[0044] Step s3: Cool the material obtained in step s2 to 65° C., then add the remaining raw materials, continue stirring at a speed of 200 r / min for 30 minutes, and then cool the material to 60° C. to obtain glue.

[0045] Preparation Example 2 A glue for sealant, which is different from Preparation Example 1 in that the amounts of various raw materials used are inconsistent.

[0046] Wherein, the preparation method of glue comprises the following steps: Step s1: Add polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol and bio-based polyol into a three-necked flask according to the formula, start stirring and stir at a speed of 180r / min, turn on the electric furnace and heat to 115°C. When the temperature reaches 115°C, turn on the vacuum pump, and draw vacuum negative pressure dehydration at a vacuum degree of -0.1MPa. When the moisture content of the dehydrated mixture is below 0.05%, stop heating and cool down.

[0047] Step s2: The temperature of the material obtained in step s1 is lowered to 80°C, and isocyanatepropyltriethoxysilane and diphenylmethane diisocyanate are slowly added in batches. The total addition time is controlled within 30 minutes. After the addition is completed, the reaction is kept at 80°C for 2 hours.

[0048] Step s3: Cool the material obtained in step s2 to 65° C., then add the remaining raw materials, continue stirring at a speed of 180 r / min for 30 minutes, and then cool the material to 60° C. to obtain glue.

[0049] Preparation Example 3 A glue for sealant, which is different from Preparation Example 1 in that the amounts of various raw materials used are inconsistent.

[0050] Wherein, the preparation method of glue comprises the following steps: Step s1: Add polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol and bio-based polyol into a three-necked flask according to the formula, start stirring and stir at a speed of 220r / min, turn on the electric furnace and heat to 110°C. When the temperature reaches 110°C, turn on the vacuum pump, and vacuum dehydrate at a vacuum degree of -0.09MPa. When the moisture content of the dehydrated mixture is below 0.05%, stop heating and cool down.

[0051] Step s2: The temperature of the material obtained in step s1 is lowered to 85°C, and isocyanatepropyltriethoxysilane and diphenylmethane diisocyanate are slowly added in batches. The total addition time is controlled within 30 minutes. After the addition, the reaction is kept at 85°C for 1.5 hours.

[0052] Step s3: Cool the material obtained in step s2 to 70° C., then add the remaining raw materials, continue stirring at a speed of 220 r / min for 30 minutes, and then cool the material to 55° C. to obtain glue.

[0053] Preparation Example 4 A glue for sealant, which is different from Preparation Example 1 in that it also includes a curing aid.

[0054] The curing aid is prepared by mixing trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether in a mass ratio of 1:1.

[0055] Wherein, trimethylolpropane triglycidyl ether is trimethylolpropane triglycidyl ether PB06397 produced by Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0056] Among them, dodecyl polyoxyethylene ether is the emulsifier OP-10 of Jinan Shengda Chemical Co., Ltd.

[0057] Wherein, the curing aid is added in step s3.

[0058] Preparation Example 5 A glue for sealant, which is different from Preparation Example 1 in that it also includes a curing aid.

[0059] The curing aid is prepared by mixing trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether in a mass ratio of 1:1.37.

[0060] Wherein, trimethylolpropane triglycidyl ether is trimethylolpropane triglycidyl ether PB06397 produced by Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0061] Among them, dodecyl polyoxyethylene ether is the emulsifier OP-10 of Jinan Shengda Chemical Co., Ltd.

[0062] Wherein, the curing aid is added in step s3.

[0063] The amounts of the raw materials used in the sealant glue of Preparation Examples 1-5 are shown in Table 1.

[0064] Table 1: Preparation Example 6 A glue for sealant, which is different from Preparation Example 4 in that trimethylolpropane triglycidyl ether is replaced by ethylene glycol diglycidyl ether.

[0065] Preparation Example 7 A glue for sealant, which is different from Preparation Example 4 in that dodecyl polyoxyethylene ether is replaced by octylphenol polyoxyethylene ether, namely, emulsifier OP-6.

[0066] Comparative Preparation Example 1 A glue for sealant, which is different from Preparation Example 1 in that an equal amount of bio-based polyol is replaced by polypropylene glycol.

[0067] Example 1 An underwater curing polyurethane sealant comprises glue, dioctyl terephthalate, a wetting dispersant, a water remover, a thixotropic agent, a filler, magnesium fluoride, carbon black and an ultraviolet absorber.

[0068] Among them, the glue comes from Preparation Example 1.

[0069] Wherein, dioctyl terephthalate is dioctyl terephthalate DOTP produced by Shandong Lanfan Chemical Co., Ltd.

[0070] Among them, the wetting and dispersing agent is the polyurethane wetting agent WL-201 produced by Guangzhou Longchi New Material Technology Co., Ltd.

[0071] Among them, the dehydrating agent is the polyurethane-specific molecular sieve activated powder of Jiangxi Xintao Technology Co., Ltd.

[0072] Among them, the thixotropic agent is the thixotropic powder B50 of Guangzhou Longchi New Material Technology Co., Ltd.

[0073] Among them, the filler is calcium carbonate JY-250 produced by Lianzhou Jinyu Plastic Filler Co., Ltd.

[0074] Among them, magnesium fluoride is nano magnesium fluoride produced by Hangzhou Zheming New Materials Co., Ltd.

[0075] Here, the carbon black is carbon black MA100 produced by Mitsubishi Chemical Corporation.

[0076] The ultraviolet absorber is the ultraviolet absorber UV-5411 produced by BASF AG.

[0077] The method for preparing the underwater curing polyurethane sealant comprises the following steps: Step 1: Add dioctyl terephthalate and wetting and dispersing agent into a double planetary mixer according to the formula, start stirring and stir at a speed of 70r / min, then slowly add plasticizer, wetting and dispersing agent, dehydrating agent, thixotropic agent, filler, magnesium fluoride, carbon black, and ultraviolet absorber. The total addition time is controlled within 30 minutes, and then slowly stir for 40 minutes.

[0078] Step 2: Add glue to the material obtained in step 1, and then continue to stir at a speed of 200r / min until it is evenly stirred. Then, vacuum degassing is performed at -0.07MPa for 40min, and then vacuum degassing is performed at -0.09MPa for 20min. Stop stirring to obtain underwater curing polyurethane sealant.

[0079] Example 2 An underwater curing polyurethane sealant, which is different from Example 1 in that the amounts of various raw materials used are inconsistent.

[0080] Among them, the glue comes from Preparation Example 2.

[0081] The method for preparing the underwater curing polyurethane sealant comprises the following steps: Step 1: Add dioctyl terephthalate and wetting and dispersing agent into a double planetary mixer according to the formula, start stirring and stir at a speed of 60r / min, then slowly add plasticizer, wetting and dispersing agent, dehydrating agent, thixotropic agent, filler, magnesium fluoride, carbon black, and ultraviolet absorber. The total addition time is controlled within 30 minutes, and then slowly stir for 40 minutes.

[0082] Step 2: Add glue to the material obtained in step 1, and then continue to stir at a speed of 180r / min until it is evenly stirred. Then, vacuum degassing is performed at -0.06MPa for 40 minutes, and then vacuum degassing is performed at -0.09MPa for 20 minutes. Stop stirring to obtain underwater curing polyurethane sealant.

[0083] Example 3 An underwater curing polyurethane sealant, which is different from Example 1 in that the amounts of various raw materials used are inconsistent.

[0084] Among them, the glue comes from Preparation Example 3.

[0085] The method for preparing the underwater curing polyurethane sealant comprises the following steps: Step 1: Add dioctyl terephthalate and wetting and dispersing agent into a double planetary mixer according to the formula, start stirring and stir at a speed of 80r / min, then slowly add plasticizer, wetting and dispersing agent, dehydrating agent, thixotropic agent, filler, magnesium fluoride, carbon black, and ultraviolet absorber. The total addition time is controlled within 30 minutes, and then slowly stir for 40 minutes.

[0086] Step 2: Add glue to the material obtained in step 1, and then continue to stir at a speed of 220r / min until it is evenly stirred. Then, vacuum degassing is performed at -0.07MPa for 35min, and then vacuum degassing is performed at -0.095MPa for 15min. Stop stirring to obtain underwater curing polyurethane sealant.

[0087] The amounts of raw materials used in Examples 1-3 are shown in Table 2.

[0088] Table 2: Example 4 An underwater curing polyurethane sealant, which is different from Example 1 in that the glue comes from Preparation Example 4.

[0089] Example 5 An underwater curing polyurethane sealant, which is different from Example 1 in that the glue comes from Preparation Example 5.

[0090] Example 6 An underwater curing polyurethane sealant, which is different from Example 1 in that the glue comes from Preparation Example 6.

[0091] Example 7 An underwater curing polyurethane sealant, which is different from Example 1 in that the glue comes from Preparation Example 7.

[0092] Comparative Example 1 An underwater curing polyurethane sealant, which is different from Example 1 in that the glue comes from Comparative Preparation Example 1.

[0093] Comparative Example 2 An underwater curing polyurethane sealant, which is different from Example 1 in that an equal amount of magnesium fluoride is replaced by nano titanium dioxide.

[0094] Performance Testing Referring to the testing method of JC / T 482-2022 "Polyurethane Building Sealant", the relevant properties of the underwater curing polyurethane sealants of the above embodiments and comparative examples were tested, and the test results are shown in Table 3.

[0095] The bonding strength retention rate (%) was calculated based on the bonding strength (dry).

[0096] Among them, the conditions of ultraviolet irradiation are: 50w / m2 energy, wavelength 300-400nm, 500h.

[0097] Table 3: Specifically analyzing in combination with Examples 1-7 and Comparative Examples 1-2, it can be seen that the underwater curing polyurethane sealant of the present application performs well in underwater surface drying time, bonding strength, and resistance to salt spray and ultraviolet radiation.

[0098] Specifically analyzing in combination with Example 1 and Examples 4-7, the difference between Examples 4-5 and Example 1 is that a curing aid is added, and the difference between Examples 6-7 and Example 4 is that trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether in the curing aid are replaced respectively. From the comparison of the test data in Table 3, it can be seen that the curing aid formed by mixing trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether has a good effect on improving the bonding strength and environmental resistance of underwater curing polyurethane sealant. It can be seen that the curing aid formed by mixing trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether can better shorten the curing time and further improve the bonding strength after curing, thereby achieving better rapid curing and high bonding strength effects.

[0099] Specifically analyzing Example 1 and Comparative Example 1, the difference between Example 1 and Comparative Example 1 lies in the introduction of bio-based polyols. It can be seen that further introducing bio-based polyols on the basis of polyether polyols can not only improve the environmental performance of the sealant, but also significantly enhance the flexibility and bonding strength of the glue.

[0100] Specifically combined with the analysis of Example 1 and Comparative Example 2, the difference between Example 1 and Comparative Example 2 is that magnesium fluoride is replaced by nano titanium dioxide in equal amounts. From the comparison of the test data in Table 3, it can be seen that the introduction of magnesium fluoride improves the weather resistance and chemical corrosion resistance of the sealant, and also has a positive effect on improving the bonding performance of the sealant.

[0101] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An underwater curing polyurethane sealant, characterized in that: The invention comprises the following components in percentage by mass: 28.41%-39.52% glue, 20%-25% dioctyl terephthalate, 0.1%-0.5% wetting and dispersing agent, 1%-2% dewatering agent, 30%-40% thixotropic agent, 4%-6% filler, 1%-2% magnesium fluoride, 0.1%-1% carbon black, and 0.1%-0.3% ultraviolet absorber; The glue comprises the following raw materials in parts by weight: 9-10 parts of polyoxyethyl polyoxypropyl glyceryl ether, 12-15 parts of polypropylene glycol, 0.1-0.5 parts of bio-based polyols, 0.1-0.5 parts of isocyanatepropyl triethoxysilane, 0.1-0.2 parts of γ-glycidyloxypropyl trimethoxysilane, 3-5 parts of diphenylmethane diisocyanate, 0.01-0.02 parts of drying agent, 0.1-0.3 parts of defoaming agent, 3-6 parts of diluent, and 1-2 parts of latent curing agent.

2. The underwater curing polyurethane sealant according to claim 1, characterized in that: The glue also includes 0.3-0.5 parts of a curing aid, which is a mixture of trimethylolpropane triglycidyl ether and dodecyl polyoxyethylene ether in a mass ratio of 1: (1-1.37).

3. The underwater curing polyurethane sealant according to claim 2, characterized in that: The glue includes the following raw materials in parts by mass: 9.43 parts of polyoxyethyl polyoxypropyl glyceryl ether, 13.72 parts of polypropylene glycol, 0.3 parts of bio-based polyol, 0.3 parts of isocyanatepropyl triethoxysilane, 0.15 parts of γ-glycidyloxypropyl trimethoxysilane, 4.01 parts of diphenylmethane diisocyanate, 0.012 parts of drying agent, 0.2 parts of defoaming agent, 4.32 parts of diluent, 1.1 parts of latent curing agent, and 0.37 parts of curing aid.

4. An underwater curing polyurethane sealant according to any one of claims 1 to 3, characterized in that: The preparation method of the glue comprises the following steps: Step s1: polyoxyethyl polyoxypropyl glyceryl ether, polypropylene glycol and bio-based polyol are stirred and mixed according to the formula, and heated to 110-115° C. When the temperature reaches 110-115° C., vacuum negative pressure dehydration is performed, and when the moisture content of the dehydrated mixture is below 0.05%, heating is stopped and the temperature is lowered; Step s2: lower the temperature of the material obtained in step s1 to 80-85°C, slowly add isocyanatepropyltriethoxysilane and diphenylmethane diisocyanate in batches, and control the total addition time within 30 minutes. After the addition, keep the temperature at 80-85°C for 1.5-2 hours; Step s3: Cool the material obtained in step s2 to 65-70°C, then add the remaining raw materials, continue stirring for 30 minutes, and then cool the material to 55-60°C to obtain glue.

5. The underwater curing polyurethane sealant according to claim 4, characterized in that: The step s1 is to stir at a speed of 180-220 r / min and to dehydrate under vacuum at a vacuum degree of -0.09 to -0.1 MPa.

6. The underwater curing polyurethane sealant according to claim 1, characterized in that: The underwater curing polyurethane sealant comprises the following components in percentage by mass: 33.912% glue, 22.028% dioctyl terephthalate, 0.33% wetting and dispersing agent, 1.38% dewatering agent, 35.16% thixotropic agent, 5.16% filler, 1.32% magnesium fluoride, 0.5% carbon black, and 0.21% ultraviolet absorber.

7. A method for preparing an underwater curing polyurethane sealant according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Mix dioctyl terephthalate and wetting and dispersing agent according to the formula, and then slowly add plasticizer, wetting and dispersing agent, dehydrating agent, thixotropic agent, filler, magnesium fluoride, carbon black, and ultraviolet absorber. The total adding time is controlled within 30 minutes, and then slowly stir for 40 minutes; Step 2: Add glue to the material obtained in step 1, and then continue to stir evenly, then perform vacuum negative pressure degassing for 50-60 minutes, stop stirring, and obtain underwater curing polyurethane sealant.

8. The method for preparing an underwater curing polyurethane sealant according to claim 7, characterized in that: The step 1 is stirred at a speed of 60-80 r / min, the step 2 is stirred at a speed of 180-220 r / min, and the step 2 is firstly vacuuming and degassing at negative pressure at -0.06~-0.07 MPa for 35-40 min, and then vacuuming and degassing at negative pressure at -0.095~-0.09 MPa for 15-20 min.

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