Epoxy resin structural adhesive for high-strength prefabricated pipe pile connection sealing and preparation method thereof

Abstract

The application provides an epoxy resin structural adhesive for high-strength prefabricated pipe pile connection sealing and a preparation method thereof, and relates to the technical field of building adhesive materials.The epoxy resin structural adhesive comprises component A and component B in a mass ratio of (4-6):1;the component A comprises, with the mass of the component A being 100%, 30-50% of epoxy resin, 5-15% of polyurethane modified epoxy resin, 0.05-0.30% of a coupling agent, 3-10% of an active diluent, 30-45% of functional fillers, 1-5% of an additive and 3-6% of fumed silica;the component B comprises, with the mass of the component B being 100%, 5-40% of a composite amine curing agent, 40-65% of functional fillers, 0.05-0.30% of a coupling agent, 15-18% of nano-alumina, 0.8-1.2% of a tertiary amine accelerator, 0.5-3.0% of an active diluent and 0.05-0.30% of an additive.The problems of insufficient compression resistance and poor corrosion resistance of traditional epoxy adhesives are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building adhesives, in particular to a high-strength epoxy structural adhesive for connecting and sealing prefabricated pipe piles and a preparation method thereof. BACKGROUND

[0002] In the application of traditional epoxy structural adhesives, there are three technical bottlenecks: first, the compressive strength is insufficient, the conventional formula has limited filling effect due to the imbalance of the ratio of epoxy resin to curing agent, and the compressive strength after curing is usually less than 60 MPa, which is difficult to meet the high load demand of the prestressed pipe pile interface (> 80 MPa), and is prone to interface peeling failure; second, the corrosion resistance is weak, especially in the coastal high-salt environment, the unmodified epoxy system has a salt spray test of more than 30% after 500 hours due to the residual hydrophilic groups and the unblocked chloride ion penetration channel, resulting in a significant increase in the risk of sealing failure; third, the rheological property is not properly controlled, and the existing thixotropic agent addition method is rough (such as dry mixing of fumed silica), resulting in a low thixotropic index (< 3.5) and a sag of > 3 mm, which makes it difficult to achieve self-leveling filling during construction, and the pipe pile connection is prone to voids that cause water seepage hazards. These problems seriously restrict the long-term reliability of the pipe pile structure under complex working conditions, and it is urgent to achieve breakthroughs through material system innovation and process optimization.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application aims to provide a high-strength epoxy structural adhesive for connecting and sealing prefabricated pipe piles and a preparation method thereof, which solves the problems of insufficient compressive strength, poor corrosion resistance, and difficult construction of traditional epoxy adhesives through material innovation and process optimization, and has the advantages of high strength, super corrosion resistance, easy construction, and low cost, providing a high-reliability sealing solution for harsh scenes such as marine engineering and bridge pile foundation.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The present application provides a high-strength epoxy structural adhesive for connecting and sealing prefabricated pipe piles, which comprises A component and B component with a mass ratio of (4-6) : 1.

[0007] The A component comprises epoxy resin 30-50%, polyurethane modified epoxy resin 5-15%, coupling agent 0.05-0.30%, active diluent 3-10%, functional filler 30-45%, auxiliary agent 1-5%, and fumed silica 3-6%, based on 100% of the mass of the A component.

[0008] The B component comprises, taking the mass of the B component as 100%, 5-40% of a composite amine curing agent, 40-65% of a functional filler, 0.05-0.30% of a coupling agent, 15-18% of nano-aluminum oxide, 0.8-1.2% of a tertiary amine accelerator, 0.5-3.0% of an active diluent, and 0.05-0.30% of an auxiliary agent.

[0009] Further, on the basis of the above technical solutions, the epoxy resin comprises one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and phenolic epoxy resin.

[0010] And / or, the polyurethane modified epoxy resin is SL3411 toughened polyurethane modified epoxy resin.

[0011] And / or, the auxiliary agent comprises one or more of a rheological agent and a defoaming agent.

[0012] And / or, the active diluent comprises one or more of carbon dodecyl-tetradecyl glycidyl ether, cashew phenol glycidyl ether, cyclohexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0013] And / or, the functional filler comprises 50-100 mesh quartz sand, 200-400 mesh quartz sand, and 800-1000 mesh silicon powder in a mass ratio of (1-2):1:(3-5).

[0014] And / or, the particle size of the fumed silica is 7-40 nm.

[0015] Further, on the basis of the above technical solutions, the composite amine curing agent comprises polyamide type epoxy resin curing agent, modified aliphatic amine type curing agent, and aromatic modified amine curing agent in a mass ratio of 1:1:(2-5).

[0016] The polyamide curing agent comprises one or more of Versamid 140, Ancamide 500-A, or Aradur 250.

[0017] The modified aliphatic amine curing agent comprises one or more of Ancamine 2014FG, Cardolite NX-5451, or Aradur 2963.

[0018] The aromatic modified amine curing agent comprises one or more of D.E.H. 85, Epikure 3115, or Aradur 917.

[0019] And / or, the coupling agent comprises at least one of silane coupling agent KH-560h or silane coupling agent KH-550.

[0020] And / or, the tertiary amine accelerator includes one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyl dimethylamine, dimethylaminomethyl phenol;

[0021] And / or, the particle size of the nano-aluminum oxide is 30-50nm, and the specific surface area is >180m 2 / g.

[0022] The application also provides a preparation method of the high-strength precast pipe pile connecting sealing epoxy structural adhesive as described above, comprising the following steps:

[0023] S1: preheat the epoxy resin and the polyurethane modified epoxy resin to obtain a mixed resin;

[0024] S2: add an active diluent to the mixed resin, perform first stirring, add part of fumed silica to perform second stirring, further add a filler to perform third stirring, and obtain a first mixture;

[0025] S3: pre-mix a coupling agent with the remaining fumed silica to obtain a second mixture, spray the second mixture into the first mixture, perform fourth stirring, and finally perform vacuum defoaming to obtain an A component material;

[0026] S4: activate a composite amine curing agent to obtain an activated amine curing agent;

[0027] S5: pre-mix nano-aluminum oxide with a coupling agent to obtain a third mixture, add the third mixture to the activated amine curing agent, perform fifth stirring, add a tertiary amine accelerator, perform sixth stirring, and finally perform homogenization treatment and vacuum defoaming to obtain a B component material;

[0028] S6: mix the A component material and the B component material to obtain a high-strength precast pipe pile connecting sealing epoxy structural adhesive.

[0029] Further, in the above technical solution, in step S1, the preheating temperature is 45-55℃, the preheating time is 20-35min, and the viscosity of the mixed resin is 800-1000mPa·s.

[0030] Further, in the above technical solution, in step S2, the first stirring speed is 150-200rpm, and the time is 5-10min;

[0031] And / or, in step S2, the part of fumed silica added accounts for 40-55% of the total mass of fumed silica;

[0032] And / or, in step S2, the third stirring speed is 800-1000 rpm, and the stirring time is 10-15 min.

[0033] And / or, in step S2, the third stirring speed is 800-1000 rpm, and the stirring time is 10-15 min.

[0034] And / or, in step S2, the filler is added in batches, and each batch is added after 2-3 min.

[0035] Further, in the above technical solution, in step S3, the pre-mixed stirring speed is 500-600 rpm, and the stirring time is 10-15 min.

[0036] And / or, in step S3, the spraying mode is atomizing spraying, the atomizing spraying pressure is 0.3-0.5 MPa, and the second mixture is atomized into 50-100 μm droplets.

[0037] And / or, in step S3, the fourth stirring speed is 500-600 rpm, and the stirring time is 10-15 min.

[0038] And / or, in step S3, the vacuum defoaming includes:

[0039] The pressure is -0.03 to -0.01 MPa, the temperature is 35-45℃, the time is 20-25 min, and the bubble volume fraction is <0.5%.

[0040] Further, in the above technical solution, in step S4, the activation includes the following steps:

[0041] The composite amine curing agent is stirred at a speed of 150-200 rpm and heated to 40-50℃, and then nitrogen is introduced to remove water for 30 min to obtain an activated amine curing agent.

[0042] The moisture content in the activated amine curing agent is ≤0.3% of the total volume of the activated amine curing agent.

[0043] Further, in the above technical solution, in step S5, the nano-aluminum oxide and the coupling agent are pre-mixed on a ball mill at a mass ratio of 8-10:1, the ball mill speed is 250-350 rpm, and the ball mill time is 2-2.5 h.

[0044] And / or, in step S5, the fifth stirring speed is 400-500 rpm, and the stirring time is 15-20 min.

[0045] And / or, in step S5, the third mixture is added to the activated amine curing agent in batches, each time with an interval of 2-3 min.

[0046] And / or, in step S5, the sixth stirring is at a speed of 100-200 rpm for 10-15 min.

[0047] And / or, in step S5, the homogenization treatment is high-speed dispersion at a speed of 1000-1500 rpm for 5-10 min.

[0048] And / or, in step S5, the vacuum defoaming includes:

[0049] The pressure is -0.09 to -0.05 MPa, the temperature is 35-45℃, the time is 10-15 min, and the bubble volume fraction is <0.5%.

[0050] Further, on the basis of the above technical solution, in step S6, the A component material and the B component material are mixed at a temperature of 10-35℃ for 5-10 min using a static mixer or a double screw continuous mixer.

[0051] The present application provides a kind of high-strength prefabricated pipe pile connection sealing epoxy resin structural adhesive and its preparation method, beneficial effects are as follows:

[0052] 1, the high-strength prefabricated pipe pile connection sealing epoxy resin structural adhesive provided by the present application has a large curing network crosslinking density, and the compressive strength can reach 85.7 MPa, while maintaining its elongation at break >4%, thixotropy index is 4.8, to ensure that pipe pile interface construction has anti-sagging property (sag <1mm) and self-leveling ability (completely wet interface within 30 seconds), so that there is no gap in pipe pile connection sealing.

[0053] 2, by adding silicon powder in filler, the present application can effectively fill the submicron pores of epoxy resin matrix, improve the density of composite material, silicon powder can also form "nanometer core-micron shell" structure with fumed silica, which can effectively improve the mechanical properties of the material, and silicon powder can form a tortuous penetration path in the curing system, so that the diffusion of chloride ions is reduced, thereby effectively improving the salt fog resistance of the material.

[0054] 3, by adding fumed silica, the reversible formation and destruction of its hydrogen bond network endow the epoxy resin structural adhesive with thixotropic properties of "static high viscosity, low viscosity under shear", so as to realize the key performance of self-leveling filling, anti-sagging and gap elimination in pipe pile sealing application, and the surface modification optimizes the interfacial bonding strength and corrosion resistance. DETAILED DESCRIPTION

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0056] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0057] According to a first aspect of the present invention, a high-strength epoxy resin structural adhesive for sealing precast pipe pile connections is provided, comprising component A and component B in a mass ratio of (4-6):1, for example, 4.5:1, 5:1, 5.5:1, etc.

[0058] Based on the mass of component A as 100%, component A includes 30-50% epoxy resin (e.g., 35%, 40%, 45%, etc.), 5-15% polyurethane modified epoxy resin (e.g., 7%, 10%, 13%, etc.), 0.05-0.30% coupling agent (e.g., 0.1%, 0.15%, 0.2%, 0.25%, etc.), 3-10% reactive diluent (e.g., 5%, 7%, 9%, etc.), 30-45% functional filler (e.g., 33%, 35%, 38%, 40%, 42%, etc.), 1-5% additives (e.g., 2%, 3%, 4%, etc.), and 3-6% fumed silica (e.g., 3.5%, 4%, 4.5%, 5%, 5.5%, etc.).

[0059] Based on the mass of component B as 100%, component B includes 5-40% (e.g., 10%, 20%, 30%, 35%) of composite amine curing agent, 40-65% (e.g., 45%, 50%, 55%, 60%) of functional filler, 0.05-0.30% (e.g., 0.1%, 0.2%, 0.25%) of coupling agent, 15-18% (e.g., 15.5%, 16%, 16.5%, 17%, 17.5%) of nano-alumina, 0.8-1.2% (e.g., 1%, 1.1%) of tertiary amine accelerator, 0.5-3.0% (e.g., 1%, 2%, 2.5%) of reactive diluent, and 0.05-0.30% (e.g., 0.1%, 0.2%) of additives.

[0060] Specifically, the present application limits the mass ratio of the A component and the B component to (4-6):1, because under the condition of the mass ratio, the curing network crosslinking density of the prepared epoxy resin structural adhesive for connecting and sealing high-strength precast pipe piles can be maximized, so that the compressive strength thereof can reach 85.7 MPa, while the elongation at break thereof is >4%, the thixotropic index thereof is 4.8, the anti-sagging property (sagging <1 mm) and the self-leveling ability (completely wetting the interface within 30 seconds) of the pipe pile interface during construction are ensured, and the sealing of the pipe pile connection is gap-free.

[0061] As an optional embodiment of the present application, the epoxy resin comprises one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and phenolic epoxy resin;

[0062] The polyurethane-modified epoxy resin is SL3411 toughened polyurethane-modified epoxy resin;

[0063] The auxiliary agent comprises one or more of rheological agents and defoaming agents; typically and non-limitingly, the auxiliary agent is a rheological agent, a defoaming agent, etc. commonly used in the art, the rheological agent is an organic modified sheet silicate BYK1958, and the defoaming agent is BYKA530.

[0064] The active diluent comprises one or more of carbon dodecyl-tetradecyl glycidyl ether, cardanol glycidyl ether, cyclohexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether;

[0065] The functional filler comprises 50-100 mesh quartz sand, 200-400 mesh quartz sand, and 800-1000 mesh (such as 850 mesh, 900 mesh, 950 mesh, etc.) silica powder in a mass ratio of (1-2):1:(3-5) (such as 1.5:1:4, 1:1:3.5, 2:1:4.5, etc.); typically and non-limitingly, the present application dopes 800-1000 mesh silica powder in the filler, because the addition of silica powder can effectively fill the submicron-sized pores of the epoxy resin matrix, improve the density of the composite material, the silica powder can form a "nanometer core-micron shell" structure with fumed silica, which can effectively improve the mechanical properties of the material, and the silica powder can form a tortuous penetration path in the curing system, so as to reduce the diffusion of chloride ions, thereby effectively improving the salt spray resistance of the material.

[0066] The particle size of the fumed silica is 7-40nm (such as 10nm, 20nm, 30nm, 35nm, etc.), and the fumed silica is reversibly formed and destroyed through a hydrogen bond network, which gives the epoxy resin structural adhesive a thixotropic property of "static high viscosity and low viscosity under shear", so as to realize the key performance of self-leveling filling, anti-sagging and void elimination in the pipe pile sealing application, and meanwhile, the interface bonding strength and corrosion resistance are optimized through surface modification.

[0067] As an optional embodiment of the present application, the composite amine curing agent comprises a polyamide type epoxy resin curing agent, a modified aliphatic amine curing agent and an aromatic modified amine curing agent in a mass ratio of 1:1:(2-5) (such as 1:1:3, 1:1:4, etc.);

[0068] The polyamide curing agent comprises one or more of Versamid 140, Ancamide 500-A or Aradur 250;

[0069] The modified aliphatic amine curing agent comprises one or more of Ancamine 2014FG, Cardolite NX-5451 or Aradur 2963;

[0070] The aromatic modified amine curing agent comprises one or more of D.E.H. 85, Epikure 3115 or Aradur 917.

[0071] Specifically, the present application adopts a composite amine curing agent, and limits the mass ratio of the polyamide type epoxy resin curing agent, the modified aliphatic amine curing agent and the aromatic modified amine curing agent to be 1:1:(2-5) because, under the limitation of the mass ratio, the polyamide curing agent can construct a crosslinking network in the curing middle period (69-90min); the modified aliphatic amine can quickly construct a crosslinking skeleton in the curing initial period (0-30min); and the aromatic modified amine can complete deep crosslinking in the curing late period (6-24h), and the three kinds of curing agents are used in combination, so that the compressive strength of the prepared composite material is greater than 80MPa.

[0072] The coupling agent comprises at least one of silane coupling agent KH-560 or silane coupling agent KH-550;

[0073] The tertiary amine accelerator comprises one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine and dimethylaminomethylphenol;

[0074] Specifically, the present application adopts a tertiary amine accelerator because the lone pair of electrons in the tertiary amine molecule can attack the oxygen atom in the epoxy group to form an oxygen anion intermediate, significantly reduce the activation energy of ring-opening reaction, and accelerate the hydrogen transfer reaction of the amine curing agent, so as to form a more uniform crosslinking network.

[0075] The particle size of the nano-alumina is 30-50 nm (such as 35 nm, 40 nm, 45 nm, etc.), and the specific surface area is >180 m 2 / g, such as 200 m 2 / g, 250 m 2 / g, 300 m 2 / g, etc.

[0076] Specifically, the present application limits the particle size of the nano-alumina to 30-50 nm, because the nano-alumina with a particle size of 30-50 nm can effectively penetrate the molecular chain gap (chain spacing of about 5-10 nm) of the epoxy resin, enhance the interface bonding strength through the "pinning effect", and form a "nano-micron" compound system with the filler, so that the tortuosity coefficient of the chloride ion penetration path is increased, thereby effectively improving the salt fog resistance of the composite material; if the particle size of the nano-alumina is too large, the barrier network porosity will increase, and if the particle size of the nano-alumina is too small, the high specific surface area will cause the resin-particle friction resistance to increase dramatically.

[0077] According to a second aspect of the present application, a preparation method of the high-strength precast pipe pile connecting sealing epoxy structural adhesive as described above is provided, comprising the following steps:

[0078] S1: preheating the epoxy resin and the polyurethane modified epoxy resin to obtain a mixed resin;

[0079] S2: adding an active diluent to the mixed resin, performing first stirring, adding part of fumed silica for second stirring, further adding a filler, performing third stirring, and obtaining a first mixture;

[0080] S3: pre-mixing a coupling agent with the remaining fumed silica to obtain a second mixture, spraying the second mixture into the first mixture, performing fourth stirring, and finally performing vacuum degassing to obtain an A component material;

[0081] S4: activating a composite amine curing agent to obtain an activated amine curing agent;

[0082] S5: pre-mixing nano-alumina with a coupling agent to obtain a third mixture, adding the third mixture into the activated amine curing agent, performing fifth stirring, adding a tertiary amine accelerator, performing sixth stirring, and finally performing homogenization treatment and vacuum degassing to obtain a B component material;

[0083] S6: mixing the A component material and the B component material to obtain a high-strength precast pipe pile connecting sealing epoxy structural adhesive.

[0084] As an optional embodiment of the present application, in step S1, the preheating temperature is 45-55℃, the preheating time is 20-35min, and the viscosity of the mixed resin is 800-1000mPa·s.

[0085] Specifically, the viscosity of the resin after preheating is reduced from 1500-2000mPa·s at room temperature to 800-1000mPa·s, and at a lower viscosity, the filler is more easily sheared and dispersed, reducing the shear energy consumption during the dispersion of the filler and improving the dispersion uniformity.

[0086] As an optional embodiment of the present application, in step S2, the first stirring speed is 150-200rpm, and the time is 5-10min.

[0087] In step S2, the added part of fumed silica accounts for 40-55% (such as 45%, 50%, 53%, etc.) of the total mass of fumed silica;

[0088] Specifically, the present application first adds part of fumed silica, and then adds the remaining fumed silica, which aims to construct a three-dimensional thixotropic network and modify the interface in a gradient manner. Specifically:

[0089] (1) In step S2, part of the fumed silica is added first, so that the fumed silica is broken under high-speed stirring to avoid secondary agglomeration when the filler is added later, and a preliminary hydrogen bond network is formed to provide a structural framework for subsequent addition and reduce the initial viscosity of the system;

[0090] (2) In step S3, the remaining fumed silica is added and pre-mixed with the coupling agent, which is to form Si-O-Si bonds by reacting silane coupling agent with the hydroxyl groups on the surface of fumed silica, thereby improving the bonding strength between fumed silica and resin; and the later-added fumed silica can fill the gaps in the preformed network, hinder the migration path of chloride ions, improve the salt mist resistance of the material, and also increase the final thixotropic index to 4.8 and the sag to <1mm. In addition, by adding fumed silica twice, the viscosity of the entire system can be gently increased, avoiding the significant increase in viscosity of the entire system caused by one-time addition, which affects the performance of the material and makes it difficult to achieve self-leveling filling during construction.

[0091] In step S2, the second stirring speed is 1000-1200rpm, the time is 10-15min, and the temperature is ≤50℃;

[0092] In step S2, the third stirring speed is 800-1000rpm, and the time is 10-15min.

[0093] In step S2, the fillers are added in batches, with each interval being 2-3min.

[0094] As an optional embodiment of the present application, in step S3, the stirring speed of the premixing is 500-600 rpm, and the time is 10-15 min.

[0095] In step S3, the spraying mode is atomization spraying, the pressure of the atomization spraying is 0.3-0.5 MPa, and the second mixture is atomized into liquid droplets with a size of 50-100 μm.

[0096] In step S3, the fourth stirring speed is 500-600 rpm, and the time is 10-15 min.

[0097] In step S3, the vacuum defoaming includes:

[0098] The pressure is -0.03 to -0.01 MPa, the temperature is 35-45 °C, the time is 20-25 min, and the bubble volume fraction is <0.5%.

[0099] As an optional embodiment of the present application, in step S4, the activation includes the following steps:

[0100] The composite amine curing agent is stirred at a speed of 150-200 rpm and heated to 40-50 °C, and then nitrogen is introduced to remove water for 30 min to obtain an activated amine curing agent; water will hydrolyze the primary amine / secondary amine groups in the amine curing agent to generate inactive amino alcohol, resulting in a decrease in the effective amine hydrogen concentration and a decrease in the crosslinking density, so that water removal operation is required.

[0101] The water content in the activated amine curing agent accounts for ≤0.3% of the total volume of the activated amine curing agent.

[0102] As an optional embodiment of the present application, in step S5, the nano-aluminum oxide and the coupling agent are premixed on a ball mill at a mass ratio of 8-10:1, the ball mill speed is 250-350 rpm, and the ball mill time is 2-2.5 h.

[0103] Specifically, the nano-aluminum oxide and the coupling agent are first premixed, which aims to modify the surface of the nano-aluminum oxide with the coupling agent, thereby improving the dispersibility of the nano-aluminum oxide and forming a uniform three-dimensional barrier network in the epoxy matrix, so as to effectively block the penetration of chloride ions and significantly improve the salt spray resistance of the material.

[0104] In step S5, the fifth stirring speed is 400-500 rpm, and the time is 15-20 min.

[0105] In step S5, the third mixture is added to the activated amine curing agent in batches, and each addition is separated by 2-3 min.

[0106] The stirring speed in step S5 is 100-200 rpm, and the time is 10-15 min.

[0107] In step S5, the homogenization treatment refers to high-speed dispersion at a speed of 1000-1500 rpm for 5-10 min.

[0108] In step S5, the vacuum defoaming includes:

[0109] The pressure is -0.09 to -0.05 MPa, the temperature is 35-45℃, the time is 10-15 min, and the bubble volume fraction is <0.5%.

[0110] Specifically, the purpose of the vacuum defoaming in steps S3 and S5 is to completely eliminate the residual bubbles in the colloid through a negative pressure environment, so as to guarantee the mechanical properties, interface sealing property and long-term durability of the material.

[0111] As an optional embodiment of the present application, in step S6, the A component material and the B component material are mixed at a temperature of 10-35℃ for 5-10 min by using a static mixer or a double screw continuous mixer.

[0112] The present application will be further described in detail below in combination with specific examples and comparative examples.

[0113] Example 1

[0114] The epoxy resin structural adhesive for high-strength prefabricated pipe pile connection sealing includes an A component and a B component with a mass ratio of 4:1.

[0115] The A component includes bisphenol A type epoxy resin 40%, SL3411 toughened polyurethane modified epoxy resin 10%, coupling agent (KH-560 and KH-550 with a mass ratio of 1:1) 0.10%, glycerol triglycidyl ether 3.9%, functional filler (50 mesh quartz sand, 400 mesh quartz sand and 800 mesh silica powder with a mass ratio of 2:1:3) 40%, auxiliary agent (organic modified sheet silicate BYK1958, BYKA530) 3%, fumed silica (particle size 30 nm) 3%, based on 100% of the mass of the A component.

[0116] The B component includes a complex amine curing agent (Versamid 140, Ancamine 2014FG and D.E.H. 85 with a mass ratio of 1:1:3) 35%, a functional filler (50 mesh quartz sand, 400 mesh quartz sand and 800 mesh silica powder with a mass ratio of 2:1:3) 45.5%, a coupling agent (KH-560 and KH-550 with a mass ratio of 1:1) 0.20%, nano-alumina (particle size 40 nm, specific surface area 250 m 2 / g) 16%, 2,4,6-tris (dimethylaminomethyl) phenol 1%, glycerol triglycidyl ether 2.0%, auxiliary (organic modified sheet silicate BYK1958, BYK A530) 0.30%.

[0117] The preparation method of the epoxy resin structural adhesive for connecting and sealing high-strength prefabricated pipe piles comprises the following steps:

[0118] S1: preheat the epoxy resin and the polyurethane modified epoxy resin at a temperature of 50 DEG C for 30 min to obtain a mixed resin, wherein the viscosity of the mixed resin is 950 mPa s;

[0119] S2: add an active diluent to the mixed resin to perform first stirring, add part of fumed silica to perform second stirring, and further add fillers in three batches with an interval of 2 min to perform third stirring to obtain a first mixture;

[0120] The speed of the first stirring is 200 rpm, and the time is 8 min;

[0121] The speed of the second stirring is 1100 rpm, the time is 13 min, and the temperature is 40 DEG C;

[0122] The speed of the third stirring is 900 rpm, and the time is 15 min;

[0123] The part of fumed silica accounts for 50% of the total mass of fumed silica;

[0124] S3: pre-mix a coupling agent with the remaining fumed silica to obtain a second mixture, spray the second mixture into the first mixture to perform fourth stirring, and finally perform vacuum defoaming to obtain an A component material;

[0125] The speed of the pre-mixing stirring is 600 rpm, and the time is 15 min;

[0126] The pressure of the spray is 0.4 MPa, and the second mixture is atomized into 50-100 mu m droplets;

[0127] The fourth stirring speed is 600 rpm, and the time is 15 min;

[0128] The vacuum defoaming includes:

[0129] The pressure is -0.03 MPa, the temperature is 40 DEG C, the time is 20 min, and the bubble volume fraction is <0.5%;

[0130] S4: The composite amine curing agent is heated and stirred at a speed of 200 rpm to 50 DEG C, nitrogen is introduced to remove water for 30 min, and an activated amine curing agent is obtained;

[0131] The moisture content in the activated amine curing agent accounts for 0.1% of the total volume of the activated amine curing agent;

[0132] S5: The nano-aluminum oxide and the coupling agent are premixed on a ball mill at a mass ratio of 10:1, the ball mill speed is 300 rpm, the ball mill time is 2 h, a third mixture is obtained, the third mixture is added to the activated amine curing agent in three batches, the fifth stirring is carried out, the tertiary amine accelerator is added, the sixth stirring is carried out, and finally the homogenization treatment and the vacuum defoaming are carried out, and a B component material is obtained;

[0133] The fifth stirring speed is 500 rpm, and the time is 20 min;

[0134] The sixth stirring speed is 200 rpm, and the time is 15 min;

[0135] The homogenization treatment refers to high-speed dispersion at a speed of 1500 rpm for 8 min;

[0136] The vacuum defoaming includes:

[0137] The pressure is -0.09 MPa, the temperature is 35 DEG C, the time is 15 min, and the bubble volume fraction is <0.5%.

[0138] S6: The A component material and the B component material are mixed at a temperature of 25 DEG C for 5 min by using a static mixer or a double screw continuous mixer, and an epoxy resin structural adhesive for high-strength precast pipe pile connection sealing is obtained.

[0139] Example 2

[0140] The epoxy resin structural adhesive for high-strength precast pipe pile connection sealing includes an A component and a B component at a mass ratio of 5:1;

[0141] The A component includes phenolic epoxy resin 50%, SL3411 toughened polyurethane modified epoxy resin 5%, coupling agent (mass ratio of KH-560 and KH-550 is 1:1) 0.30%, glycerol triglycidyl ether 5%, functional filler (mass ratio of 50 mesh quartz sand, 400 mesh quartz sand and 800 mesh silica powder is 2:1:3) 32.7%, auxiliary agent (organic modified sheet silicate BYK1958, BYKA530) 1%, fumed silica (particle size is 35nm) 6%, taking the mass of the A component as 100%;

[0142] The B component includes composite amine curing agent (mass ratio of Versamid140, Ancamine 2014FG and D.E.H.85 is 1:1:5) 20.2%, functional filler (mass ratio of 50 mesh quartz sand, 400 mesh quartz sand and 800 mesh silica powder is 2:1:3) 57%, coupling agent (mass ratio of KH-560 and KH-550 is 1:1) 0.30%, nano-alumina (particle size is 40nm, specific surface area is 280m 2 / g) 18%, 2,4,6-tris(dimethylaminomethyl)phenol 1.2%, glycerol triglycidyl ether 3.0%, auxiliary agent (organic modified sheet silicate BYK1958, BYKA530) 0.30%, taking the mass of the B component as 100%.

[0143] The preparation method of the epoxy resin structural adhesive for connecting and sealing high-strength prefabricated pipe piles comprises the following steps:

[0144] S1: preheat the epoxy resin and the polyurethane modified epoxy resin at a temperature of 55℃ for 20min to obtain a mixed resin, and the viscosity of the mixed resin is 1000mPa·s;

[0145] S2: add an active diluent to the mixed resin to perform first stirring, add part of fumed silica to perform second stirring, and further add fillers in three batches with an interval of 3min to perform third stirring to obtain a first mixture;

[0146] The speed of the first stirring is 150rpm, and the time is 10min;

[0147] The speed of the second stirring is 1000rpm, the time is 10min, and the temperature is 45℃;

[0148] The speed of the third stirring is 1000rpm, and the time is 15min;

[0149] The part of fumed silica accounts for 50% of the total mass of fumed silica;

[0150] S3: After pre-mixing the coupling agent with the remaining fumed silica, a second mixture is obtained, the second mixture is atomized and sprayed into the first mixture, a fourth stirring is performed, and finally a vacuum degassing is performed to obtain the A component material;

[0151] The pre-mixing stirring speed is 500 rpm, and the time is 10 min;

[0152] The atomized spraying pressure is 0.5 MPa, and the second mixture is atomized into 50-100 μm droplets;

[0153] The fourth stirring speed is 500 rpm, and the time is 10 min;

[0154] The vacuum degassing includes:

[0155] The pressure is -0.01 MPa, the temperature is 45°C, the time is 25 min, and the bubble volume fraction is <0.5%;

[0156] S4: The composite amine curing agent is stirred and heated to 50°C at a speed of 200 rpm, and then nitrogen is introduced to remove water for 30 min to obtain an activated amine curing agent;

[0157] The moisture content in the activated amine curing agent is ≤0.3% of the total volume of the activated amine curing agent;

[0158] S5: The nano-alumina and the coupling agent are pre-mixed in a mass ratio of 9:1 on a ball mill, the ball milling speed is 350 rpm, and the ball milling time is 2 h to obtain a third mixture, the third mixture is added to the activated amine curing agent in three batches, a fifth stirring is performed, a tertiary amine promoter is added, a sixth stirring is performed, and finally a homogenization treatment and a vacuum degassing are performed to obtain the B component material;

[0159] The fifth stirring speed is 400 rpm, and the time is 15 min;

[0160] The sixth stirring speed is 100 rpm, and the time is 10 min;

[0161] The homogenization treatment refers to high-speed dispersion at a speed of 1000 rpm for 5 min;

[0162] The vacuum degassing includes:

[0163] The pressure is -0.05 MPa, the temperature is 45°C, the time is 15 min, and the bubble volume fraction is <0.5%.

[0164] S6: The A component material is mixed with the B component material at a temperature of 35℃ using a static mixer or a twin-screw continuous mixer for 10 minutes to obtain an epoxy resin structural adhesive for high-strength precast pile connection sealing.

[0165] Comparative Example 1

[0166] The main difference between this comparative example and Example 1 is that the mass ratio of the A component and the B component is 3:1, and the remaining steps and technical parameters are the same as those of Example 1.

[0167] Comparative Example 2

[0168] The main difference between this comparative example and Example 1 is that no silicon powder is added to the filler, and all of it is quartz sand, specifically 50 mesh quartz sand and 400 mesh quartz sand in a mass ratio of 2:1, and the remaining steps and technical parameters are the same as those of Example 1.

[0169] Comparative Example 3

[0170] The main difference between this comparative example and Example 1 is that no nano-alumina is added, specifically:

[0171] The B component includes 40% of a composite amine curing agent (Versamid 140, Ancamine 2014FG, and D.E.H. 85 in a mass ratio of 1:1:3), 56.5% of a functional filler (50 mesh quartz sand, 400 mesh quartz sand, and 800 mesh silicon powder in a mass ratio of 2:1:3), 0.20% of a coupling agent (KH-560 and KH-550 in a mass ratio of 1:1), 1% of 2,4,6-tris(dimethylaminomethyl)phenol, 2.0% of glycerol triglycidyl ether, and 0.30% of an auxiliary agent (organic modified sheet silicate BYK1958 and BYK A530), based on 100% of the mass of the B component.

[0172] Comparative Example 4

[0173] The main difference between this comparative example and Example 1 is that all the fumed silica is added at once in step S2, and the remaining steps and technical parameters are the same as those of Example 1.

[0174] Comparative Example 5

[0175] The main difference between this comparative example and Example 1 is that in step S5, the nano-alumina and the coupling agent are not pre-mixed first, but are directly added to the activated amine curing agent for the fifth stirring, and the remaining steps and technical parameters are the same as those of Example 1.

[0176] Performance Test

[0177] Compressive strength: test standard refers to GB / T 2567-2021;

[0178] Elongation at break: test standard refers to ASTM D638;

[0179] Thixotropic index: test standard refers to ISO 3219;

[0180] Anti-sagging property: test standard refers to ASTM D2202;

[0181] Self-leveling ability: test standard refers to ISO 13007-1:2020;

[0182] Salt spray test: test standard refers to ASTM B117-19.

[0183] As the epoxy resin structural adhesive suitable for the sealing of prefabricated pipe pile connection, the elongation at break thereof should be controlled in 3-5%, the compressive strength is >80 MPa, the thixotropic index is 4.5-4.8, and the sag is <1 mm.

[0184] Effect data

[0185] The performance test results of the structural adhesive prepared in the examples and comparative examples are shown in Table 1:

[0186] Table 1

[0187]

[0188] According to Table 1, compared with Example 1, the curing network crosslinking density of the epoxy resin structural adhesive for high-strength prefabricated pipe pile connection sealing prepared in Comparative Example 1 is smaller due to the mass ratio of A component and B component being 3:1, which affects the mechanical properties of the structural adhesive.

[0189] According to Table 1, compared with Example 1, the mechanical properties of the structural adhesive are affected due to the lack of silicon powder in Comparative Example 2, which cannot produce a synergistic effect with fumed silica, and the salt spray resistance and flowability of the structural adhesive are also affected.

[0190] According to Table 1, compared with Example 1, the mechanical properties of the structural adhesive are affected due to the lack of nano-aluminum oxide in Comparative Example 3, and the salt spray resistance of the structural adhesive is also significantly reduced.

[0191] According to Table 1, compared with Example 1, the viscosity of the whole system is significantly increased due to the one-time addition of all fumed silica in Comparative Example 4, which affects the bonding strength with the resin, reduces the mechanical properties and salt spray resistance of the structural adhesive, and makes it difficult to achieve self-leveling filling.

[0192] According to Table 1, compared with Example 1, in the comparative example 5, the nano-alumina is not pre-mixed with the coupling agent, which leads to the agglomeration of the nano-alumina, and not only affects the mechanical properties of the structural adhesive, but also significantly reduces the salt fog resistance and fluidity of the structural adhesive.

[0193] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An epoxy resin structural adhesive for high-strength precast pipe pile connection sealing, characterized by, The A component and the B component include a mass ratio of (4-6):1; The A component includes, based on 100% of the mass of the A component, 30-50% of an epoxy resin, 5-15% of a polyurethane modified epoxy resin, 0.05-0.30% of a coupling agent, 3-10% of an active diluent, 30-45% of a functional filler, 1-5% of an auxiliary agent, and 3-6% of fumed silica; The B component includes, based on 100% of the mass of the B component, 5-40% of a composite amine curing agent, 40-65% of a functional filler, 0.05-0.30% of a coupling agent, 15-18% of nano-alumina, 0.8-1.2% of a tertiary amine accelerator, 0.5-3.0% of an active diluent, and 0.05-0.30% of an auxiliary agent; The functional filler includes 50-100 mesh quartz sand, 200-400 mesh quartz sand, and 800-1000 mesh silica powder in a mass ratio of (1-2):1:(3-5); The preparation method of the epoxy structural adhesive for high-strength prefabricated pipe pile connection sealing includes the following steps: S1: preheat the epoxy resin and the polyurethane modified epoxy resin to obtain a mixed resin; S2: add the active diluent to the mixed resin, perform first stirring, add part of the fumed silica to perform second stirring, further add the functional filler to perform third stirring, and obtain a first mixture; S3: pre-mix the coupling agent with the remaining fumed silica to obtain a second mixture, spray the second mixture into the first mixture, perform fourth stirring, and finally perform vacuum degassing to obtain the A component material; S4: activate the composite amine curing agent to obtain an activated amine curing agent; S5: pre-mix the nano-alumina with the coupling agent to obtain a third mixture, add the third mixture into the activated amine curing agent, perform fifth stirring, add the tertiary amine accelerator, perform sixth stirring, and finally perform homogenization treatment and vacuum degassing to obtain the B component material; S6: mix the A component material and the B component material to obtain the epoxy structural adhesive for high-strength prefabricated pipe pile connection sealing.

2. The epoxy structural adhesive for high-strength precast pile connection sealing according to claim 1, characterized in that, The epoxy resin includes one or more of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, and phenolic epoxy resin; And / or, the polyurethane modified epoxy resin is SL3411 toughened polyurethane modified epoxy resin; And / or, the auxiliary agent includes one or more of a rheological agent and a defoaming agent; And / or, the active diluent includes one or more of carbon twelve to fourteen alkyl glycidyl ether, cashew phenol glycidyl ether, cyclohexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether; And / or, the particle size of the fumed silica is 7-40 nm.

3. The epoxy structural adhesive for high-strength precast pile connection sealing according to claim 1, characterized in that, The composite amine curing agent includes a polyamide type epoxy resin curing agent, a modified aliphatic amine curing agent, and an aromatic modified amine curing agent in a mass ratio of 1:1:(2-5); The polyamide curing agent includes one or more of Versamid 140, Ancamide 500-A, or Aradur 250; The modified fatty amine curing agent includes one or more of Ancamine 2014FG, Cardolite NX-5451 or Aradur 2963; The aromatic modified amine curing agent includes one or more of D.E.H. 85, Epikure 3115 or Aradur 917; And / or, the coupling agent includes at least one of silane coupling agent KH-560 or silane coupling agent KH-550; And / or, the tertiary amine accelerator includes one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, dimethylaminomethylphenol; And / or, the nano-alumina has a particle size of 30-50 nm and a specific surface area of >180 m² / g.

4. The epoxy structural adhesive for high-strength precast pile connection sealing according to claim 1, characterized in that, In step S1, the preheating temperature is 45-55℃, the preheating time is 20-35 min, and the viscosity of the mixed resin is 800-1000 mPa·s.

5. The epoxy structural adhesive for high strength precast pile connection sealing according to claim 1, characterized in that, In step S2, the first stirring speed is 150-200 rpm, and the time is 5-10 min; And / or, in step S2, the added part of fumed silica accounts for 40-55% of the total mass of fumed silica; And / or, in step S2, the second stirring speed is 1000-1200 rpm, the time is 10-15 min, and the temperature is ≤50℃; And / or, in step S2, the third stirring speed is 800-1000 rpm, and the time is 10-15 min; And / or, in step S2, the functional filler is added in batches, with an interval of 2-3 min each time.

6. The epoxy structural adhesive for high strength precast pile connection sealing according to claim 1, characterized in that, In step S3, the pre-mixed stirring speed is 500-600 rpm, and the time is 10-15 min; And / or, in step S3, the spraying mode is atomizing spraying, the atomizing spraying pressure is 0.3-0.5 MPa, and the second mixture is atomized into 50-100 μm droplets; And / or, in step S3, the fourth stirring speed is 500-600 rpm, and the time is 10-15 min; And / or, in step S3, the vacuum degassing includes: The pressure is -0.03~-0.01 MPa, the temperature is 35-45℃, the time is 20-25 min, and the bubble volume fraction is <0.5%.

7. The epoxy structural adhesive for high strength precast pile connection sealing according to claim 1, characterized in that, In step S4, the activation includes the following steps: The composite amine curing agent is stirred at a speed of 150-200 rpm and heated to 40-50℃, and then nitrogen is introduced to remove water for 30 min to obtain an activated amine curing agent; The moisture content in the activated amine curing agent is ≤0.3% of the total volume of the activated amine curing agent.

8. The epoxy structural adhesive for high strength precast pile connection sealing according to claim 1, characterized in that, In step S5, the nano-alumina and the coupling agent are pre-mixed on a ball mill at a mass ratio of 8-10:1, the ball mill speed is 250-350 rpm, and the ball mill time is 2-2.5 h; And / or, in step S5, the fifth stirring speed is 400-500 rpm, and the time is 15-20 min; And / or, in step S5, the third mixture is added to the activated amine curing agent in batches, each time with an interval of 2-3 min; And / or, in step S5, the sixth stirring is performed at a stirring speed of 100-200 rpm for 10-15 min; And / or, in step S5, the homogenization treatment refers to high-speed dispersion at a speed of 1000-1500 rpm for 5-10 min; And / or, in step S5, the vacuum defoaming includes: The pressure is -0.09~-0.05 MPa, the temperature is 35-45 ℃, the time is 10-15 min, and the bubble volume fraction is <0.5%.

9. The epoxy structural adhesive for high strength precast pile connection sealing according to claim 1, characterized in that, In step S6, the A component material and the B component material are mixed at a temperature of 10-35 ℃ using a static mixer or a twin-screw continuous mixer for 5-10 min.

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