Epoxy resin tack coat oil material suitable for steel bridge deck

Abstract

The invention discloses an epoxy resin tack coat oil material suitable for a steel bridge deck, which constructs a multi-scale toughening composite system through the synergistic effect of an epoxy-terminated polyurethane elastomer toughening agent (molecular-scale chemical grafting) and a nano-scale elastomer filler (nano dispersion toughening), and solves the problem of rigidity-flexibility imbalance of the traditional epoxy tack coat oil. The material has the advantages of fast curing (surface drying at 25 DEG C is less than or equal to 4 hours), high toughness (the elongation at break is greater than or equal to 250%) and excellent weather resistance (the performance retention rate is greater than or equal to 85% after ultraviolet aging for 500 hours), and is suitable for interlayer interface bonding of steel bridge deck pit slot and crack repair. According to the preparation method, uniform dispersion and interface chemical bonding of the nanofiller are achieved through a segmented stirring process, the comprehensive performance of the material is remarkably improved, and the important engineering application value is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering materials, and specifically to a steel bridge deck epoxy resin tack coat material having high bonding strength, excellent low-temperature toughness and rapid curing properties, as well as a preparation method and engineering application thereof based on multi-scale synergistic toughening. Background Art

[0002] Steel bridge deck pavement is prone to defects such as potholes and cracks in complex environments such as heavy traffic, temperature cycles, and rainwater erosion. Tack coats are required to ensure reliable bonding between the repair layer and the original pavement. Existing epoxy tack coats offer high strength and excellent temperature resistance, but they exhibit high crosslink density and significant brittleness after curing, making them susceptible to interfacial cracking at low temperatures. Asphalt tack coats offer excellent flexibility but lack high-temperature stability, making them difficult to meet long-term service requirements. While existing technologies have improved epoxy brittleness by adding toughening agents, they generally suffer from the following drawbacks:

[0003] Single toughening method: Traditional toughening agents (such as liquid nitrile rubber) are dispersed only through physical blending, which has poor interfacial compatibility with epoxy resin and is prone to phase separation after long-term service;

[0004] Imbalance between curing speed and flexibility: Although fast curing agents can shorten the curing time, the cross-linking density of the cured product is high, the elongation at break is usually less than 150%, and the low-temperature deformation capacity is insufficient;

[0005] Insufficient interface bonding reliability: There is an oxide layer and a humid environment on the steel bridge deck. The traditional adhesive layer oil and the substrate are mainly physically adsorbed, and the bonding strength is easily affected by the environment.

[0006] In response to the above problems, the present invention proposes a dual-active end-group chemical grafting and nano-dispersion synergistic toughening system. Through molecular-level toughening agent design, nano-filler synergistic modification and interfacial chemical bonding technology, the integrated improvement of the "rapid curing-high toughness-weather resistance" of the tack layer oil is achieved, filling the gap in the existing technology. Summary of the Invention

[0007] The purpose of this invention is to provide an epoxy resin tack coat material suitable for steel bridge deck repair. By designing a multi-scale toughening system, this material addresses the "rigidity-flexibility imbalance" problem of conventional epoxy tack coats and achieves the following performance breakthroughs:

[0008] Fast curing: surface drying time at 25℃≤4h, meeting the demand for rapid opening of steel bridge decks to traffic;

[0009] High toughness and deformation coordination: elongation at break ≥ 250%, no cracks when bent at -10℃, adaptable to deformation of steel bridge decks;

[0010] Excellent interface bonding and weather resistance: bonding strength on wet surface ≥2.8MPa, performance retention rate ≥85% after 500h of UV aging.

[0011] In order to achieve the above object, the present invention is implemented through the following technical solution: an epoxy resin adhesive layer oil material suitable for steel bridge decks, comprising:

[0012] Component A is an epoxy resin and component B is an epoxy curing agent. Components A and B achieve a balance of rigidity and flexibility through a dual-active end-group chemical grafting and nano-dispersion synergistic toughening system.

[0013] The component A comprises, by weight, 100 parts of a general-purpose epoxy resin, 10-30 parts of an epoxy-terminated polyurethane elastomer toughening agent, the molecular chain of which has epoxy groups at both ends and a polyether-type flexible segment in the middle, with a molecular weight of 5000-15000 g / mol, and 5-20 parts of a flexible diluent;

[0014] The component B comprises, by mass, 100 parts of a fast curing agent, 30-80 parts of a flexible curing agent, 5-15 parts of a nano-elastomer toughening filler, and 3-8 parts of a silane coupling agent;

[0015] The mass ratio of component A to component B is 100:70-130.

[0016] As a further improvement to the technical solution of the present invention, the epoxy-terminated polyurethane elastomer toughening agent is prepared by the following steps:

[0017] (1) Polypropylene glycol, molecular weight 700-2000 g / mol, vacuum dehydration at 110-130°C, -0.08 to -0.10 MPa for 2.5-3 h;

[0018] (2) reacting polypropylene glycol and toluene diisocyanate at a molar ratio of 1:2.0-2.2 until the NCO content of the system is reduced to 40%-60% of the initial value to prepare an NCO-terminated prepolymer;

[0019] (3) According to the molar ratio of hydroquinone diglycidyl ether to prepolymer of 2:1.0-1.2, 2-ethyl-4-methylimidazole catalyst was added in an amount of 6.0±0.5×10 -3 mmol / g hydroquinone diglycidyl ether, react at 150-170℃ until the NCO content is 0, forming an elastomer segment terminated with epoxy groups at both ends.

[0020] As a further improvement of the technical solution of the present invention, the fast curing agent is one of ketimine, modified polythiol GLS810 or curing agent TX-B1, and the molecular structure of the fast curing agent contains latent amino active groups, which can react with epoxy resin on a moist base surface with a moisture content of ≤15%, and the surface drying time at 25°C is ≤3.5h.

[0021] As a further improvement of the technical solution of the present invention, the flexible curing agent is a compound of polyetheramine D2000 with a molecular weight of 2000 g / mol and polythiol 309 in a mass ratio of 1:0.5-1.5, and the length of the polyether chain segment in its molecular chain is ≥10 repeating units, so that the elongation at break of the cured material is ≥250% and the tensile strength is ≥6 MPa.

[0022] As a further improvement to the technical solution of the present invention, the particle size of the nano-elastomer toughening filler EP-1861 is 50-100nm, and the surface is pretreated with a silane coupling agent to form elastic micro-regions with an island structure in the curing system, with a micro-region spacing of ≤200nm, which effectively inhibits crack propagation.

[0023] As a further improvement to the technical solution of the present invention, the silane coupling agent is KH570 or DL171, the silane alkoxy group in the molecule can form a Si-O-Fe covalent bond with the Fe3O4 oxide layer of the steel bridge deck, and the organic functional group methacryloyloxy or amino group is cross-linked with the epoxy resin, thereby increasing the steel-epoxy interface bonding strength by more than 40%, and the bonding strength on a moist base surface at 25°C is ≥2.8 MPa.

[0024] As a further improvement to the technical solution of the present invention, the universal epoxy resin is E51 or E54, and its epoxy value is 0.48-0.54eq / 100g, which forms a gradient cross-linking density network with the epoxy group of the epoxy-terminated polyurethane elastomer toughening agent, so that the material has a storage modulus of 1.5-2.0GPa at 25°C and a loss factor tanδ≥0.3, and has both rigid support and flexible deformation capabilities.

[0025] As a further improvement to the technical solution of the present invention, a method for preparing an epoxy resin tack coat material suitable for steel bridge decks comprises:

[0026] (1) Preparation of component A: Stir the general-purpose epoxy resin, epoxy-terminated polyurethane elastomer toughening agent, and softening diluent at 800-1000 rpm for 15-20 minutes at 45-55°C to form a molecularly homogeneous dispersion system;

[0027] (2) Preparation of component B: First, disperse the nano-scale elastomer toughening filler and the silane coupling agent at 60-70°C at a high speed of 1200-1500 r / min for 15-20 minutes to achieve surface coupling modification of the filler, and then add the fast curing agent and the flexible curing agent and mix at a low speed of 500-700 r / min for 30-40 minutes;

[0028] (3) Mixing process: Stir components A and B at 300-500 r / min for 3-5 min at 20-25 °C to form a multi-scale toughening composite system, including molecular chain toughening, nanoparticle toughening and interfacial chemical bonding.

[0029] As a further improvement to the technical solution of the present invention, the softening diluent is propoxylated glycerol glycidyl ether or para-sec-butylphenyl glycidyl ether, and its added amount is correlated with the hydroxyl value of the epoxy-terminated polyurethane elastomer toughening agent, satisfying the formula: softening diluent portion = 0.8 × epoxy-terminated polyurethane elastomer toughening agent hydroxyl value, mmol / g × 10, to ensure system compatibility.

[0030] As a further improvement of the technical solution of the present invention, an application of epoxy resin adhesive layer oil material suitable for steel bridge deck: when used for steel bridge deck repair, 0.3-0.6kg / m 2 , after 24 hours:

[0031] Steel-asphalt interface shear strength ≥ 1.5 MPa, test method ASTM D3078, test temperature 60°C;

[0032] -10℃ low temperature flexural modulus ≤1.2GPa, no cracks when bent 180°;

[0033] UV aging uses UVA-340 light source. After 500 hours of irradiation, the tensile strength retention rate is ≥85%, and the elongation at break retention rate is ≥75%.

[0034] The present invention has the following beneficial effects:

[0035] Multi-scale toughening mechanism

[0036] Molecular-level toughening: The diepoxy end groups of PU-ET are chemically grafted with epoxy resin to form a cross-linked network with dispersed flexible segments, increasing the elongation at break to over 250%;

[0037] Nano-level toughening: EP-1861 elastic micro-regions are evenly dispersed with a spacing of ≤200nm, effectively hindering crack propagation, and the low-temperature flexural modulus is ≤1.2GPa (-10℃);

[0038] Interface enhancement: Silane coupling agent forms Si-O-Fe covalent bonds, and the bonding strength on the wet base surface is ≥2.8MPa, which is 40% higher than that of traditional epoxy.

[0039] Gradient cross-linking density design

[0040] The general-purpose epoxy resin (epoxy value 0.48-0.54eq / 100g) works synergistically with the epoxy group of PU-ET to form a "rigid skeleton-flexible chain segment" gradient cross-linked network with a storage modulus of 1.5-2.0GPa at 25°C and a loss factor tanδ≥0.3, combining load-bearing capacity and deformation compliance.

[0041] Fast curing and weather resistance

[0042] The latent fast curing agent can achieve surface drying time of ≤3.5h at 25℃. Combined with nano-fillers and anti-UV structural design, the tensile strength retention rate after 500h of UV aging is ≥85%, meeting the long-term service requirements of steel bridge decks. DETAILED DESCRIPTION

[0043] The present invention will be described in detail below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0044] In the present invention, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, "connection" can mean fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two elements, or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0045] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one such feature. Furthermore, the technical solutions of various embodiments may be combined with each other, but only on the basis that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions contradicts or cannot be implemented, it shall be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this disclosure.

[0046] An epoxy resin tack coat material suitable for steel bridge decks, comprising:

[0047] Component A is an epoxy resin and component B is an epoxy curing agent. Components A and B achieve a balance of rigidity and flexibility through a dual-active end-group chemical grafting and nano-dispersion synergistic toughening system.

[0048] The component A comprises, by weight, 100 parts of a general-purpose epoxy resin, 10-30 parts of an epoxy-terminated polyurethane elastomer toughening agent, the molecular chain of which has epoxy groups at both ends and a polyether-type flexible segment in the middle, with a molecular weight of 5000-15000 g / mol, and 5-20 parts of a flexible diluent;

[0049] The component B comprises, by mass, 100 parts of a fast curing agent, 30-80 parts of a flexible curing agent, 5-15 parts of a nano-elastomer toughening filler, and 3-8 parts of a silane coupling agent;

[0050] The mass ratio of component A to component B is 100:70-130.

[0051] Specifically, in this embodiment, the epoxy-terminated polyurethane elastomer toughening agent is prepared by the following steps:

[0052] (1) Polypropylene glycol, molecular weight 700-2000 g / mol, vacuum dehydration at 110-130°C, -0.08 to -0.10 MPa for 2.5-3 h;

[0053] (2) reacting polypropylene glycol and toluene diisocyanate at a molar ratio of 1:2.0-2.2 until the NCO content of the system is reduced to 40%-60% of the initial value to prepare an NCO-terminated prepolymer;

[0054] (3) According to the molar ratio of hydroquinone diglycidyl ether to prepolymer of 2:1.0-1.2, 2-ethyl-4-methylimidazole catalyst was added in an amount of 6.0±0.5×10 -3 mmol / g hydroquinone diglycidyl ether, react at 150-170℃ until the NCO content is 0, forming an elastomer segment terminated with epoxy groups at both ends.

[0055] Specifically, in this embodiment, the fast curing agent is one of ketimine, modified polythiol GLS810 or curing agent TX-B1. The molecular structure of the fast curing agent contains a latent amino active group, which can react with the epoxy resin on a moist base surface with a moisture content of ≤15%, and the surface drying time at 25°C is ≤3.5h.

[0056] Specifically, in this embodiment, the flexible curing agent is a compound of polyetheramine D2000 with a molecular weight of 2000 g / mol and polythiol 309 in a mass ratio of 1:0.5-1.5. The length of the polyether segment in its molecular chain is ≥10 repeating units, so that the elongation at break of the cured material is ≥250% and the tensile strength is ≥6 MPa.

[0057] Specifically, the nano-elastomer toughening filler EP-1861 described in this embodiment has a particle size of 50-100 nm, and its surface is pretreated with a silane coupling agent to form elastic micro-domains with an island structure in the curing system, with a micro-domain spacing of ≤200 nm, effectively inhibiting crack propagation.

[0058] Specifically, in this embodiment, the silane coupling agent is KH570 or DL171, the silane alkoxy group in the molecule can form a Si-O-Fe covalent bond with the Fe3O4 oxide layer on the steel bridge deck, and the organic functional group methacryloyloxy or amino group cross-links with the epoxy resin, thereby increasing the steel-epoxy interface bonding strength by more than 40%, and the bonding strength on a wet base surface at 25°C is ≥2.8 MPa.

[0059] Specifically, in this embodiment, the general-purpose epoxy resin is E51 or E54, and its epoxy value is 0.48-0.54eq / 100g, which forms a gradient cross-linking density network with the epoxy group of the epoxy-terminated polyurethane elastomer toughening agent, so that the material has a storage modulus of 1.5-2.0GPa at 25°C and a loss factor tanδ≥0.3, and has both rigid support and flexible deformation capabilities.

[0060] Specifically, in this embodiment, a method for preparing an epoxy resin tack coat material suitable for steel bridge decks includes:

[0061] (1) Preparation of component A: Stir the general-purpose epoxy resin, epoxy-terminated polyurethane elastomer toughening agent, and softening diluent at 800-1000 rpm for 15-20 minutes at 45-55°C to form a molecularly homogeneous dispersion system;

[0062] (2) Preparation of component B: First, disperse the nano-scale elastomer toughening filler and the silane coupling agent at 60-70°C at a high speed of 1200-1500 r / min for 15-20 minutes to achieve surface coupling modification of the filler, and then add the fast curing agent and the flexible curing agent and mix at a low speed of 500-700 r / min for 30-40 minutes;

[0063] (3) Mixing process: Stir components A and B at 300-500 r / min for 3-5 min at 20-25 °C to form a multi-scale toughening composite system, including molecular chain toughening, nanoparticle toughening and interfacial chemical bonding.

[0064] Specifically, in this embodiment, the softening diluent is propoxylated glycerol glycidyl ether or p-sec-butylphenyl glycidyl ether, and its added amount is correlated with the hydroxyl value of the epoxy-terminated polyurethane elastomer toughening agent, satisfying the formula: softening diluent portion = 0.8 × epoxy-terminated polyurethane elastomer toughening agent hydroxyl value, mmol / g × 10, to ensure system compatibility.

[0065] Specifically, in this embodiment, an application of epoxy resin adhesive layer oil material suitable for steel bridge deck: when used for steel bridge deck repair, 0.3-0.6kg / m 2 , after 24 hours:

[0066] Steel-asphalt interface shear strength ≥ 1.5 MPa, test method ASTM D3078, test temperature 60°C;

[0067] -10℃ low temperature flexural modulus ≤1.2GPa, no cracks when bent 180°;

[0068] UV aging uses UVA-340 light source. After 500 hours of irradiation, the tensile strength retention rate is ≥85%, and the elongation at break retention rate is ≥75%.

[0069] Furthermore, it should be noted that component A (epoxy resin base material, parts by mass)

[0070] Universal epoxy resin (100 parts): E51 or E54 with an epoxy value of 0.48-0.54 eq / 100g is used as the basic cross-linking skeleton;

[0071] Epoxy-terminated polyurethane elastomer toughening agent (PU-ET, 10-30 parts): The molecular chain has epoxy groups at both ends and a polyether-type flexible segment (molecular weight 5000-15000 g / mol) in the middle, which forms an interpenetrating network with the epoxy resin through chemical grafting;

[0072] Softening diluent (5-20 parts): Use propoxylated glycerol glycidyl ether or p-sec-butylphenyl glycidyl ether, which contains long-chain alkyl flexible groups to adjust the viscosity and compatibility of the system.

[0073] Component B (composite curing agent, parts by mass)

[0074] Fast curing agent (100 parts): ketimine, modified polythiol GLS810 or curing agent TX-B1, containing latent amino active groups, surface drying time ≤ 3.5h at 25℃;

[0075] Flexible curing agent (30-80 parts): polyetheramine D2000 (molecular weight 2000g / mol) and polythiol 309 compound (mass ratio 1:0.5-1.5), the molecular chain contains polyether segments (length ≥10 repeating units) to reduce the crosslinking density;

[0076] Nano-scale elastomer toughening filler (EP-1861, 5-15 parts): particle size 50-100nm, surface pre-treated with silane coupling agent, forming "island structure" elastic micro-domains (spacing ≤ 200nm) in the curing system to inhibit crack propagation;

[0077] Silane coupling agent (3-8 parts): Use KH570 or DL171. The silane alkoxy group in the molecule forms a Si-O-Fe covalent bond with the Fe3O4 oxide layer on the steel bridge deck, and the organic functional group cross-links with the epoxy resin, increasing the interface bonding strength by more than 40%.

[0078] Component ratio: The mass ratio of component A to component B is 100:70-130.

[0079] (2) Preparation method of key components

[0080] Synthesis of epoxy-terminated polyurethane elastomer toughening agent (PU-ET)

[0081] (1) Polypropylene glycol (molecular weight 700-2000 g / mol) was vacuum dehydrated at 110-130°C and -0.08 to -0.10 MPa for 2.5-3 h to remove water and avoid side reactions;

[0082] (2) reacting polypropylene glycol and toluene diisocyanate (TDI) at a molar ratio of 1:2.0-2.2 until the NCO content is reduced to 40%-60% of the initial value to prepare an NCO-terminated prepolymer;

[0083] (3) According to the molar ratio of hydroquinone diglycidyl ether: prepolymer = 2:1.0-1.2, 2-ethyl-4-methylimidazole catalyst (6.0±0.5×10 -3 mmol / g hydroquinone diglycidyl ether), react at 150-170°C until the NCO content is 0, forming an elastomer segment terminated with epoxy groups at both ends.

[0084] Composite curing agent preparation process

[0085] (1) Preparation of component A: Stir the general-purpose epoxy resin, PU-ET toughening agent, and softening diluent at 800-1000 rpm for 15-20 min at 45-55°C to form a molecular-level homogeneous dispersion system;

[0086] (2) Preparation of component B: First, disperse the nano-scale elastomer filler and silane coupling agent at 60-70°C at 1200-1500 r / min for 15-20 minutes to achieve surface coupling modification of the filler, then add the fast curing agent and flexible curing agent and mix at 500-700 r / min for 30-40 minutes;

[0087] (3) Mixing process: Components A and B are stirred at 300-500 r / min for 3-5 min at 20-25 °C to form a multi-scale toughening composite system including molecular chain toughening, nanoparticle toughening and interfacial chemical bonding.

[0088] Example:

[0089] Example 1: Standard tack coat oil

[0090] Preparation of component A

[0091] 100 parts of E51 epoxy resin, 20 parts of PU-ET toughener (synthesized from polypropylene glycol 2000, molecular weight 10,000 g / mol), and 10 parts of propoxylated glyceryl glycidyl ether were added to a reactor, heated at 50° C. and stirred at 800 r / min for 15 min to form a transparent homogeneous system.

[0092] Preparation of component B

[0093] Nano-scale elastomer filler EP-1861 (10 parts) and KH570 coupling agent (5 parts) were dispersed at a high speed of 1300 r / min at 65°C for 20 minutes, and then ketimine (100 parts), polyetheramine D2000:polythiol 309 (1:1, 50 parts) were added and mixed at a low speed of 600 r / min at 60°C for 30 minutes.

[0094] Mixing and performance testing

[0095] A:B=100:120 (mass ratio), stirring at 25℃ for 4min, spreading amount 0.5kg / m 2 ;

[0096] Performance data:

[0097] Surface drying time at 25℃ is 3.5h, tensile strength after 48h is 8.2MPa, and elongation at break is 245%;

[0098] No cracks when bent 180° at -10℃, and the bonding strength on a wet surface (moisture content 10%) is 2.9MPa;

[0099] After 500h of UV aging, the tensile strength retention rate was 88% and the elongation at break retention rate was 78%.

[0100] Example 2: Low temperature adhesive layer oil

[0101] Key Adjustments

[0102] The PU-ET toughening agent is synthesized with polypropylene glycol 700 (molecular weight 700g / mol) to improve low-temperature activity;

[0103] The flexible curing agent was adjusted to polyetheramine D2000: polythiol 309 = 1:1.5 (70 parts) to increase the mercapto flexible chain segment;

[0104] The softening diluent is p-sec-butylphenyl glycidyl ether (15 parts), and the amount is calculated according to the formula "softening diluent part = 0.8 × PU-ET hydroxyl value (mmol / g) × 10".

[0105] Performance advantages

[0106] -20℃ elongation at break 185%, 60℃ steel-asphalt interfacial shear strength 1.6MPa (ASTM D3078);

[0107] After curing at 5℃ for 24 hours, the bonding strength is 2.6MPa, which meets the requirements of winter construction.

[0108] Synthesis Example of Epoxy-Terminated Polyurethane Elastomer Toughener (PU-ET)

[0109] Example A (PU-ET-700, molecular weight 700 g / mol)

[0110] Polypropylene glycol 700 (1 mol) was dehydrated in vacuum at 120 °C and -0.09 MPa for 2.5 h;

[0111] Toluene diisocyanate (TDI, 2.1 mol) was added and reacted at 80°C until the NCO content decreased from the initial 4.8% to 2.4% (about 2 h) to obtain an NCO-terminated prepolymer;

[0112] Hydroquinone diglycidyl ether (2.2 mol), catalyst 2-ethyl-4-methylimidazole (6.0×10 - 3 mmol / g hydroquinone diglycidyl ether), react at 160℃ for 3h until the NCO content is 0 to obtain a yellow transparent elastomer toughening agent.

[0113] Example B (PU-ET-2000, molecular weight 2000 g / mol)

[0114] Polypropylene glycol 2000 (1 mol) was dehydrated in vacuum at 110 °C and -0.10 MPa for 3 h;

[0115] TDI (2.0 mol) was added and the reaction was continued at 75°C until the NCO content dropped to 2.0% (initial 4.0%), for about 3 h;

[0116] Hydroquinone diglycidyl ether (2.0 mol) and a catalyst (same as above) were added, and the mixture was reacted at 150° C. for 4 h until the NCO content was 0 to obtain a low-viscosity elastomer toughening agent.

[0117] Example of tack coat oil

[0118] Example 3: High Toughness Type (Upper Limit of PU-ET Dosage, Performance at 25°C)

[0119] Component A: 100 parts of E54 epoxy resin, 30 parts of PU-ET-2000 (Example B), 15 parts of softening diluent (p-sec-butylphenyl glycidyl ether) (calculated according to the formula: PU-ET hydroxyl value 0.5 mmol / g, 15 = 0.8 × 0.5 × 10 × 3.75);

[0120] Component B: 100 parts of fast curing agent TX-B1, 80 parts of flexible curing agent (polyetheramine D2000: polythiol 309 = 1:1), 15 parts of EP-1861 nanofiller, and 8 parts of DL171 coupling agent;

[0121] A:B=100:130, stir at 25℃ for 5min, spreading amount 0.6kg / m 2 ;

[0122] performance:

[0123] Elongation at break 280%, tensile strength 7.5MPa;

[0124] -10℃ flexural modulus 1.1GPa, no cracks at 180°;

[0125] The steel-epoxy interface bonding strength (dry base surface) is 3.2MPa, and the wet base surface (moisture content 15%) is 2.8MPa.

[0126] Example 4: Fast curing type (increased proportion of fast curing agent)

[0127] Component A: 100 parts of E51 epoxy resin, 15 parts of PU-ET-700 (Example A), and 10 parts of softening diluent;

[0128] Component B: 100 parts of fast curing agent ketimine, 30 parts of flexible curing agent (polyetheramine D2000) (single component), 5 parts of EP-1861 filler, 3 parts of KH570 coupling agent;

[0129] A:B=100:70, stir at 20℃ for 3min, spreading amount 0.3kg / m 2 ;

[0130] performance:

[0131] Surface drying time at 25℃ is 2.5h, and the tensile strength after 4h is 5.0MPa (outstanding early strength);

[0132] The elongation at break is 200%, and the strength retention rate after 200h of UV aging is 90%.

[0133] Example 5: Special type for wet base surface (increase the amount of coupling agent)

[0134] Component A: 100 parts of E44 epoxy resin, 20 parts of PU-ET-2000, and 20 parts of softening diluent;

[0135] Component B: 100 parts of fast curing agent modified polythiol GLS810, 60 parts of flexible curing agent (polythiol 309: polyetheramine T5000 = 1:0.8), 10 parts of EP-1861 filler, and 8 parts of KH550 coupling agent;

[0136] A:B=100:125, stir at 25℃ for 4min, spreading amount 0.5kg / m 2 ;

[0137] performance:

[0138] The bonding strength on a wet surface (20% moisture content) is 3.0 MPa (67% higher than that of Comparative Example 3);

[0139] The elongation at break at -10℃ is 230%, which is suitable for repairing steel bridge decks in rainy areas.

[0140] Comparative Example (Compared with Traditional Technology)

[0141] Comparative Example 1: Traditional single toughening agent (without PU-ET and nanofiller)

[0142] Component A: 100 parts of E51 epoxy resin, 20 parts of liquid nitrile rubber (toughener) (physical blend), 10 parts of softening diluent;

[0143] Component B: 100 parts of common amine curing agent (non-fast type), non-flexible curing agent;

[0144] Performance drawbacks:

[0145] Surface drying time at 25°C is 8 hours, and elongation at break is 120% (significantly lower than Example 1);

[0146] -10℃ bending cracks, UV aging after 100h surface powdering, bonding strength decreased by 50%. Comparative Example 2: No nano elastomer filler (only molecular toughening)

[0147] Component B: omitting the EP-1861 filler, and the rest is the same as in Example 1;

[0148] Performance differences:

[0149] The elongation at break is 220% (down 10% compared to Example 1), the crack growth rate is accelerated by 30%; the low temperature flexural modulus is 1.4 GPa (1.2 GPa in Example 1), and the toughness improvement is not significant. Comparative Example 3: No silane coupling agent (only physical adsorption at the interface)

[0150] Component B: omitting the KH570 coupling agent, and the rest is the same as in Example 1;

[0151] Performance comparison:

[0152] The bonding strength on the wet surface was 1.7 MPa (2.9 MPa in Example 1), a decrease of 41%;

[0153] After the salt spray test (5% NaCl, 1000 h), the interface peeling area reached 30% (only 5% in Example 1).

[0154] 4. Performance comparison table of examples

[0155]

[0156]

[0157] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0158] Multi-scale toughening mechanism

[0159] Molecular-level toughening: The diepoxy end groups of PU-ET are chemically grafted with epoxy resin to form a cross-linked network with dispersed flexible segments, increasing the elongation at break to over 250%;

[0160] Nano-level toughening: EP-1861 elastic micro-regions are evenly dispersed with a spacing of ≤200nm, effectively hindering crack propagation, and the low-temperature flexural modulus is ≤1.2GPa (-10℃);

[0161] Interface enhancement: Silane coupling agent forms Si-O-Fe covalent bonds, and the bonding strength on the wet base surface is ≥2.8MPa, which is 40% higher than that of traditional epoxy.

[0162] Gradient cross-linking density design

[0163] The general-purpose epoxy resin (epoxy value 0.48-0.54eq / 100g) works synergistically with the epoxy group of PU-ET to form a "rigid skeleton-flexible chain segment" gradient cross-linked network with a storage modulus of 1.5-2.0GPa at 25°C and a loss factor tanδ≥0.3, combining load-bearing capacity and deformation compliance.

[0164] Fast curing and weather resistance

[0165] The latent fast curing agent can achieve surface drying time of ≤3.5h at 25℃. Combined with nano-fillers and anti-UV structural design, the tensile strength retention rate after 500h of UV aging is ≥85%, meeting the long-term service requirements of steel bridge decks.

[0166] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An epoxy resin tack coat material suitable for steel bridge decks, characterized in that: The invention comprises an epoxy resin component A and an epoxy curing agent component B, wherein the components A and B achieve a balance of rigidity and flexibility through a double-active end-group chemical grafting and nano-dispersion synergistic toughening system; The component A comprises, by weight, 100 parts of a general-purpose epoxy resin, 10-30 parts of an epoxy-terminated polyurethane elastomer toughening agent, the molecular chain of which has epoxy groups at both ends and a polyether-type flexible segment in the middle, with a molecular weight of 5000-15000 g / mol, and 5-20 parts of a flexible diluent; The component B comprises, by mass, 100 parts of a fast curing agent, 30-80 parts of a flexible curing agent, 5-15 parts of a nano-elastomer toughening filler, and 3-8 parts of a silane coupling agent; The mass ratio of component A to component B is 100:70-130.

2. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The epoxy-terminated polyurethane elastomer toughening agent is prepared by the following steps: (1) Polypropylene glycol, molecular weight 700-2000 g / mol, vacuum dehydration at 110-130°C, -0.08 to -0.10 MPa for 2.5-3 h; (2) reacting polypropylene glycol and toluene diisocyanate at a molar ratio of 1:2.0-2.2 until the NCO content of the system is reduced to 40%-60% of the initial value to prepare an NCO-terminated prepolymer; (3) According to the molar ratio of hydroquinone diglycidyl ether to prepolymer of 2:1.0-1.2, 2-ethyl-4-methylimidazole catalyst was added in an amount of 6.0±0.5×10 -3 mmol / g hydroquinone diglycidyl ether, react at 150-170℃ until the NCO content is 0, forming an elastomer segment terminated with epoxy groups at both ends.

3. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The fast curing agent is one of ketimine, modified polythiol GLS810 or curing agent TX-B1. The molecular structure of the fast curing agent contains latent amino active groups, can react with epoxy resin on a wet base surface with a moisture content of ≤15%, and has a surface drying time of ≤3.5h at 25°C.

4. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The flexible curing agent is a compound of polyetheramine D2000 with a molecular weight of 2000 g / mol and polythiol 309 in a mass ratio of 1:0.5-1.

5. The length of the polyether segment in its molecular chain is ≥10 repeating units, so that the elongation at break of the cured material is ≥250% and the tensile strength is ≥6 MPa.

5. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The nano-scale elastomer toughening filler EP-1861 has a particle size of 50-100 nm, and its surface is pre-treated with a silane coupling agent to form elastic micro-regions of sea-island structure in the curing system, with a micro-region spacing of ≤200 nm, effectively inhibiting crack propagation.

6. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The silane coupling agent is KH570 or DL171. The silane alkoxy group in the molecule can form a Si-O-Fe covalent bond with the Fe3O4 oxide layer on the steel bridge deck, and the organic functional group methacryloyloxy or amino group cross-links with the epoxy resin, thereby increasing the steel-epoxy interface bonding strength by more than 40%, and the bonding strength on a wet base surface at 25°C is ≥2.8MPa.

7. The epoxy resin tack coat material suitable for steel bridge decks according to claim 1, characterized in that: The universal epoxy resin is E51 or E54, and its epoxy value is 0.48-0.54eq / 100g. It forms a gradient cross-linking density network with the epoxy group of the epoxy-terminated polyurethane elastomer toughening agent, so that the material has a storage modulus of 1.5-2.0GPa at 25°C and a loss factor tanδ≥0.3, and has both rigid support and flexible deformation capabilities.

8. The method for preparing the tack coat oil material according to any one of claims 1 to 7, characterized in that: include: (1) Preparation of component A: Stir the general-purpose epoxy resin, epoxy-terminated polyurethane elastomer toughening agent, and softening diluent at 800-1000 rpm for 15-20 minutes at 45-55°C to form a molecularly homogeneous dispersion system; (2) Preparation of component B: First, disperse the nano-scale elastomer toughening filler and the silane coupling agent at 60-70°C at a high speed of 1200-1500 r / min for 15-20 minutes to achieve surface coupling modification of the filler, and then add the fast curing agent and the flexible curing agent and mix at a low speed of 500-700 r / min for 30-40 minutes; (3) Mixing process: Stir components A and B at 300-500 r / min for 3-5 min at 20-25 °C to form a multi-scale toughening composite system, including molecular chain toughening, nanoparticle toughening and interfacial chemical bonding.

9. The method for preparing an epoxy resin tack coat material suitable for steel bridge decks according to claim 8, characterized in that: The softening diluent is propoxylated glycerol glycidyl ether or p-sec-butylphenyl glycidyl ether, and its added amount is correlated with the hydroxyl value of the epoxy-terminated polyurethane elastomer toughening agent, satisfying the formula: softening diluent portion = 0.8 × epoxy-terminated polyurethane elastomer toughening agent hydroxyl value, mmol / g × 10, to ensure system compatibility.

10. The use of the tack coat oil material according to any one of claims 1 to 7, characterized in that: When used for steel bridge deck repair, spread 0.3-0.6kg / m at 5-30℃ environment. 2 , after 24 hours: Steel-asphalt interface shear strength ≥ 1.5 MPa, test method ASTM D3078, test temperature 60°C; -10℃ low temperature flexural modulus ≤1.2GPa, no cracks when bent 180°; UV aging uses UVA-340 light source. After 500 hours of irradiation, the tensile strength retention rate is ≥85%, and the elongation at break retention rate is ≥75%.

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