Epoxy-terminated polyurethane flexibilizer for bridge and tunnel pavement, and preparation and use methods thereof

Abstract

The invention relates to an epoxy-terminated polyurethane flexibilizer for bridge and tunnel pavement, and a preparation method and a use method thereof, and the flexibilizer is prepared by terminating a polyurethane prepolymer through an epoxy group of an epoxy compound under the catalytic action of nano-modified imidazole; wherein an epoxy group reacts with an NCO group at the end part of a polyurethane prepolymer, and a five-membered ring structure with high cohesive energy is introduced into a polyurethane molecular chain. A main chain of the epoxy-terminated toughening agent contains a five-membered ring structure, and the epoxy-terminated toughening agent is prepared from an epoxy group and an isocyanate group through catalysis of nano-modified imidazole at a relatively low temperature. Due to the fact that the cohesive energy of the five-membered ring is high, the steric hindrance effect is large, good high and low temperature stability is achieved, and the damping temperature range is wide. And after being cured, the curing agent has the properties of high-temperature rutting resistance, medium-temperature fatigue resistance, low-temperature crack resistance and the like, and the problem of insufficient toughness of an epoxy mixture in conventional pavement is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge and tunnel paving materials, and in particular to an epoxy-terminated polyurethane toughening agent for bridge and tunnel paving, and a preparation method and a use method thereof. Background Art

[0002] As a thermosetting polymer material, epoxy resin has been widely used in bridge and tunnel pavement due to its excellent strength, adhesion, high temperature rutting resistance and other properties. It is a good breakthrough in solving the global problem of bridge and tunnel pavement. However, unmodified epoxy resin often has problems such as excessive strength and insufficient toughness. This imbalance in properties limits its performance in certain specific application scenarios, especially in bridge and tunnel pavement that requires high toughness and fatigue resistance.

[0003] To solve this problem, the research team explored the method of using polyurethane as a toughening agent to modify epoxy resin. The flexibility of polyurethane is combined with the rigidity of epoxy resin to form a synchronous interpenetrating network structure, achieving the complementary performance of the two materials, thereby significantly improving the toughness of epoxy resin while maintaining its excellent mechanical properties. This modification method makes the application of epoxy resin in bridge and tunnel paving more extensive and reliable.

[0004] However, unmodified polyurethane contains highly active NCO groups, which easily react with water vapor in the air, resulting in gelation, which affects the long-term storage stability of the material. In addition, during the construction process, the NCO group has a high reactivity with amine curing agents, which makes the residence time of the mixture short, making it difficult to meet the construction requirements for the time window.

[0005] Chinese patent CN116854884A is a previous application of the research team, which discloses a toughening agent for high-toughness epoxy for road and bridge, including monohydroxy epoxy-terminated polyurethane prepolymer and phenol-terminated polyurethane prepolymer in a mass ratio of 100:50-200; wherein, by adjusting the ratio of monohydroxy epoxy-terminated polyurethane prepolymer and phenol-terminated polyurethane prepolymer in the toughening agent, the synchronous interpenetrating network structure is adjusted, thereby achieving the regulation of the mechanical properties of the modified epoxy resin binder. However, the synthesis process of this toughening agent is relatively complicated, and the temperature accuracy requirements are high, which easily leads to low yield in production.

[0006] Therefore, it is of great significance for the field of bridge and tunnel paving to develop a toughening agent with simple process, high yield and satisfactory construction and workability.

[0007] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0008] The first object of the present invention is to provide an epoxy-terminated polyurethane toughening agent for bridge and tunnel paving, which is used to toughen and modify epoxy resin to prepare a high and low temperature stable epoxy mixture for bridge and tunnel paving, thereby solving the problem of insufficient toughness of epoxy mixtures in conventional paving.

[0009] The above technical objectives of the present invention are achieved through the following technical solutions:

[0010] An epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement, the toughening agent is prepared by capping a polyurethane prepolymer with epoxy groups of an epoxy compound under the catalytic action of nano-modified imidazole;

[0011] Among them, the NCO group at the end of the polyurethane prepolymer preferentially reacts with the epoxy group under the action of nano-modified imidazole, introducing a five-membered ring structure into the polyurethane molecular chain. Based on the characteristics of this structure such as large steric hindrance and high cohesive energy, the toughness and high and low temperature stability of the material are significantly improved.

[0012] Furthermore, in the reaction, the molar ratio of the epoxy group to the NCO group at the end of the polyurethane prepolymer is 2.00 to 2.05: 1. In order to ensure that the epoxy group can completely block the isocyanate group, the epoxy compound should be slightly excessive to ensure that there is no NCO residue in the system.

[0013] Furthermore, the epoxy compound is one or more of E55, E51, and E44. In order to achieve epoxy termination of the isocyanate-terminated polyurethane prepolymer, the present invention utilizes the epoxy group in the epoxy compound to react with the isocyanate group in the terminal isocyanate group, and grafts the epoxy compound onto the molecular structure of the polyurethane prepolymer, thereby achieving epoxy-terminated polyurethane prepolymer.

[0014] The process route of the present invention is designed with the following two steps of reaction:

[0015] First step reaction:

[0016]

[0017] Second step reaction:

[0018]

[0019] Furthermore, the polyurethane prepolymer is prepared by reacting polyisocyanate and polyether polyol, and the molar ratio of NCO groups in the polyisocyanate to OH groups in the polyether polyol is 2.00-2.05:1.

[0020] Furthermore, the polyether polyol is one or more of polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0021] Furthermore, the polyisocyanate is one or more of TDI, MDI and HDI.

[0022] Further, the dosage of nano-modified imidazole is 0.1wt% to 0.5wt%. Due to the high cohesive energy of the five-membered ring formed after the reaction of the epoxy group and NCO, the energy barrier is large when the two react, which makes the reaction of the two difficult to a certain extent. Although unmodified imidazole can reduce the reaction activation energy between the NCO group and the epoxy group, the reaction temperature of the two is still high, and the terminal isocyanate polyurethane prepolymer has a tendency to self-polymerize under high temperature conditions. In order to promote the reaction between the epoxy group and the NCO group, the nano-modified imidazole catalyst is preferably used, and the imidazole catalyst is loaded on the surface of the nanoparticles. With the help of the characteristics of good dispersibility, large specific surface area, and outstanding quantum effect of the nanoparticles, the catalytic reaction sites are carried out on more catalytic centers, which improves the catalytic efficiency, and further reduces the difficulty of the epoxy group in the epoxy compound and the isocyanate group in the terminal isocyanate polyurethane prepolymer to react, inhibits the self-polymerization reaction between the isocyanate groups, and provides an effective way for preparing the five-membered ring compound with excellent performance.

[0023] Furthermore, the modified imidazole is a strong base. Under alkaline conditions, the active hydrogen on the secondary amine of imidazole preferentially reacts with the highly active isocyanate group to form an urethane bond. Then the nitrogen atom on the tertiary amine acts as a nucleophilic reagent to form an active intermediate with the isocyanate group, and the intermediate then adds to the epoxy group to form a five-membered ring structure. After catalysis by nano-modified imidazole, the temperature can be reduced by 15 to 35°C. This temperature difference can prevent most of the isocyanate groups from self-polymerizing, ensuring that the isocyanate groups in the system can react with the epoxy group to form a five-membered ring structure.

[0024] Nanoparticles include silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), etc. Nanoparticles have a high specific surface area and excellent surface activity. Their role is to provide a highly dispersed carrier structure for imidazole. Through the interaction between nanoparticles and imidazole, the molecular structure and charge distribution of imidazole are changed, and its catalytic activity is changed, thereby reducing the activation energy of the reaction, so that the reaction can be carried out efficiently at a lower temperature.

[0025] The second object of the present invention is to provide a method for preparing an epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement, which has the same technical effect.

[0026] The above technical objectives of the present invention are achieved by the following technical solutions:

[0027] S1: Place the dehydrated polyol in a reactor, add polyisocyanate in proportion, and heat at 75±2℃, N2 The reaction is carried out under the following conditions until the NCO content in the synthesized product reaches the target value (1 / 2 of the NCO content at the beginning of the reaction) to obtain an isocyanate-terminated polyurethane prepolymer; specifically, the target value here is different for different types of polyols and polyisocyanates. Reaching the target value (half of the initial value) indicates that an NCO-terminated polyurethane is generated, which can be used to determine whether this step of the reaction has reached the end point, and is a key indicator for whether the next step of the reaction can be carried out.

[0028] S2 Add epoxy compound and nano-modified imidazole to the isocyanate-terminated polyurethane prepolymer in proportion, and then heat at 160°C and N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthesized product was ≤0.1%, thereby obtaining an epoxy-terminated polyurethane prepolymer.

[0029] Preferably, in step S1, the polyol is heated at 105°C and N 2 dehydration treatment under conditions, gradually adding polyisocyanate to the dehydrated polyol at a molar ratio of n(NCO) / n(OH) of 2.00 to 2.05 / 1, and reacting at 75±2°C and N2 until the NCO content in the synthesized product reaches the theoretical value, thereby obtaining a terminal isocyanate polyurethane prepolymer;

[0030] Preferably, in step S2, according to n(NCO) / n(C 2 O) is 1 / 2.00-2.05, epoxy compound is added to the isocyanate-terminated polyurethane prepolymer in S1, and 0.1wt%-0.5wt% of nano-modified imidazole is added, and then heated at 120°C, N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthesized product was ≤0.1%, thereby obtaining an epoxy-terminated polyurethane prepolymer;

[0031] The third object of the present invention is to provide a method for using an epoxy-terminated polyurethane toughening agent for bridge and tunnel paving, which is mixed with liquid epoxy resin, active diluent, coupling agent, curing agent and other ingredients to prepare an epoxy binder for bridge and tunnel paving, and then put into an asphalt mixing tank to prepare an epoxy mixture for bridge and tunnel paving that is stable at high and low temperatures, which has the same technical effect.

[0032] The above technical objectives of the present invention are achieved by the following technical solutions:

[0033] A method for using an epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement comprises the following steps:

[0034] P1. Evenly mix the liquid epoxy resin, epoxy-terminated polyurethane toughening agent for bridge and tunnel paving, reactive diluent and coupling agent to obtain component A of bridge and tunnel paving material;

[0035] P2. Evenly mix the polyetheramine curing agent and the low molecular weight polyamide curing agent to obtain the bridge and tunnel paving material component B;

[0036] P3, mixing the bridge and tunnel paving material component A in P1 and the bridge and tunnel paving material component B in P2 evenly to obtain a bridge and tunnel paving material binder;

[0037] P4. Evenly mix the bridge and tunnel paving material binder and graded stone in P3 to obtain a bridge and tunnel paving material mixture.

[0038] Furthermore, a method for using an epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement is specifically as follows:

[0039] P1. Weigh liquid epoxy resin, epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement, reactive diluent, coupling agent and other components in a ratio of 10-20:70-80:10:1, then gradually heat to 40-60°C, and stir and mix for 1-3 hours to obtain component A of bridge and tunnel pavement material;

[0040] P2. Weigh the polyetheramine curing agent and low molecular weight polyamide curing agent and other components in a ratio of 1-2:1-2, then gradually heat up to 40-60°C, and stir and mix for 1-3 hours to obtain the bridge and tunnel paving material component B;

[0041] P3, preheat the high-toughness epoxy A component of P1 and the high-toughness epoxy B component of P2 to 30-40°C respectively, then weigh the A component and the B component according to the mass ratio of 2-4:1, and stir and mix for 1-3 minutes to obtain the bridge and tunnel paving material binder;

[0042] P4. Add the high-toughness epoxy binder for road and bridge in P3 into the mixing tank in proportion and mix evenly with the graded stone to obtain the bridge and tunnel paving material mixture. The mass ratio between the graded stone and the high-toughness epoxy binder for road and bridge is 100:6.0~8.0.

[0043] By means of the above technical solution, the present invention has at least the following beneficial effects:

[0044] (1) The present invention uses epoxy compounds to end-cap the terminal isocyanate polyurethane, and the NCO content in the prepared toughening agent is less than 0.1%, which can meet the requirements of long-term storage stability. Secondly, the toughening agent contains epoxy groups at both ends, which matches the curing rate of epoxy resin and has good compatibility. In addition, while grafting the epoxy groups, a five-membered ring structure with high cohesive energy is introduced into the main chain, which has good high and low temperature stability, thereby significantly broadening the damping temperature range of the modified epoxy material, so that it can maintain excellent mechanical properties within a large temperature change range in winter and summer. In addition, the five-membered ring has a large steric hindrance, which can allow a certain amount of movement space between the molecular chains. Under the external force, the molecular chains have enough space to slip and twist, thereby better dispersing and absorbing energy, further improving the toughness of the material.

[0045] (2) The present invention performs nano-modification on imidazole catalysts, which can significantly reduce the reaction energy barrier between isocyanate groups and epoxy groups, and reduce the temperature threshold of the aforementioned end-capping reaction. Under normal temperature conditions, this reaction is usually difficult to carry out, while under high temperature conditions, isocyanate groups tend to self-polymerize. Although ordinary imidazole catalysts can reduce the reaction energy barrier between the two, the reaction temperature is still relatively high. Nano-modified imidazole catalysts have the characteristics of large specific surface area and outstanding quantum effect, so that the catalytic reaction sites are carried out on more catalytic centers, which improves the catalytic efficiency, further reduces the reaction temperature, avoids the occurrence of side reactions, and provides an effective way to prepare five-membered ring compounds with excellent performance.

[0046] (3) The present invention makes the molecular design of epoxy-terminated polyurethane toughening agent highly flexible by adjusting the types and proportions of polyurethane and epoxy compounds. By adjusting the types and proportions, a series of toughening agents with five-membered ring structures can be customized. This structure is a key performance enhancement unit, and its characteristics are closely related to the molecular properties of the selected epoxy compound. Epoxy compounds with different epoxy group contents, molecular weights and functional group distributions can show different reactivity and cross-linking ability in the end-capping reaction. The toughening agent with a five-membered ring structure can be prepared by combining and matching according to actual use requirements, so that various performance parameters such as strength, toughness, fatigue performance, etc. of the material can be adjusted and controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 The figure is a schematic diagram of the five-membered ring structure in the toughening agent prepared in the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] Sources of raw materials used in the examples:

[0051] Polyisocyanate: TDI-80, MDI-100, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0052] Polyols: PPG1000, PPG2000, PPG4000, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0053] Epoxy compounds: E51, E44, Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0054] Catalyst: Imidazole, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0055] Active diluent: XY748, XY622, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0056] Coupling agent: KH560, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0057] Polyetheramine: D230, D400, Huntsman Company, USA.

[0058] Low molecular weight polyamide: Versamid 115, Versamid 140, Huntsman Company, USA.

[0059] Example 1

[0060] An epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement is prepared by capping a polyurethane prepolymer with the epoxy group of an epoxy compound E51 under the catalytic action of nano-modified imidazole; wherein the NCO group at the end of the polyurethane prepolymer preferentially reacts with the epoxy group under the action of the nano-modified imidazole, and a polyurethane prepolymer such as Figure 1 The five-membered ring structure shown in the figure significantly improves the toughness and high and low temperature stability of the material due to its large steric hindrance and high cohesive energy.

[0061] <Preparation of epoxy-terminated polyurethane toughening agent for bridge and tunnel paving>

[0062] S1. Heat PPG1000 at 105℃, N 2After dehydration for 2 hours under the conditions, TDI-80 was uniformly added dropwise to the dehydrated PPG1000 at a molar ratio of n(NCO) / n(OH) of 2.05 / 1 within two hours, and the mixture was heated at 75±2℃ and N 2 The reaction is carried out under the following conditions until the NCO content in the synthesized product reaches the theoretical value, thereby obtaining a terminal isocyanate polyurethane prepolymer;

[0063] S2, molar ratio n(NCO) / n(C 2 O) is 1 / 2.05, E51 is added to the isocyanate-terminated polyurethane prepolymer in S1, and 0.1wt% of catalyst-modified imidazole is added, and then heated at 120°C and N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthesized product was ≤0.1%, thereby obtaining the epoxy-terminated polyurethane toughening agent Z1 for bridge and tunnel pavement;

[0064] <Preparation of epoxy-terminated polyurethane binder for bridge and tunnel paving>

[0065] P1. Weigh the above raw materials in the ratio of liquid epoxy: toughening agent Z1: active diluent: coupling agent = 10:80:10:1, and mix them at 60°C with stirring for 1 hour to obtain component A of bridge and tunnel paving material;

[0066] P2. Weigh the above raw materials in order according to the ratio of polyetheramine curing agent D400: low molecular weight polyamide curing agent Versamid 115 = 1:1, and stir and mix at 40° C. for 1 hour to obtain bridge and tunnel paving material component B;

[0067] P3. Weigh the high-toughness epoxy component A and component B of the road and bridge materials in a mass ratio of 3:1, and stir and mix them at room temperature for 2 minutes to obtain the bridge and tunnel paving material binder B1. After curing at RT / 7d, relevant performance tests are carried out. The relevant properties are shown in Table 1.

[0068] <Preparation of epoxy-terminated polyurethane mixture for bridge and tunnel paving>

[0069] P4. The bridge and tunnel paving material binder B1 prepared above was mixed with stone to obtain the bridge and tunnel paving material mixture M1. After curing at RT / 7d, relevant performance tests were carried out. The relevant performances are shown in Table 1.

[0070] Table 1 Performance test data in Example 1

[0071]

[0072] Example 2

[0073] <Preparation of epoxy-terminated polyurethane toughening agent for bridge and tunnel paving>

[0074] S1. Heat PPG2000 at 105℃, N 2 After dehydration for 2 hours under the conditions, TDI-80 was uniformly added dropwise to the dehydrated PPG2000 at a molar ratio of n(NCO) / n(OH) of 2.05 / 1 within two hours, and the mixture was heated at 75±2℃ and N 2 The reaction is carried out under the following conditions until the NCO content in the synthesized product reaches the theoretical value, thereby obtaining a terminal isocyanate polyurethane prepolymer;

[0075] S2, molar ratio n(NCO) / n(C 2 O) is 1 / 2.05, E44 is added to the isocyanate-terminated polyurethane prepolymer in S1, and 0.1wt% of catalyst-modified imidazole is added, and then heated at 120°C and N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthetic product was ≤0.1%, thereby obtaining the epoxy-terminated polyurethane toughening agent Z2 for bridge and tunnel pavement;

[0076] <Preparation of epoxy-terminated polyurethane binder for bridge and tunnel paving>

[0077] P1. Weigh the above raw materials in the ratio of liquid epoxy: toughening agent Z1: active diluent: coupling agent = 10:80:10:1, and mix them at 60°C with stirring for 1 hour to obtain component A of bridge and tunnel paving material;

[0078] P2. Weigh the above raw materials in the ratio of polyetheramine curing agent D400 to low molecular weight polyamide curing agent Versamid 115 = 1:1, and mix them at 40° C. for 1 hour to obtain component B of bridge and tunnel paving material;

[0079] P3. Weigh the high-toughness epoxy component A and component B of the road and bridge materials in a mass ratio of 3:1, and stir and mix them at room temperature for 2 minutes to obtain the bridge and tunnel paving material binder B2. After curing at RT / 7d, relevant performance tests are carried out. The relevant properties are shown in Table 2.

[0080] <Preparation of epoxy-terminated polyurethane mixture for bridge and tunnel paving>

[0081] P4. The bridge and tunnel paving material binder B2 prepared above is stirred and evenly mixed with stone to obtain the bridge and tunnel paving material mixture M2. After curing at RT / 7d, relevant performance tests are carried out. The relevant performances are shown in Table 2.

[0082] Table 2 Performance test data in Example 2

[0083]

[0084] Example 3

[0085] <Preparation of epoxy-terminated polyurethane toughening agent for bridge and tunnel paving>

[0086] S1. Heat PPG4000 at 105℃, N 2 After dehydration for 2 hours under the conditions, TDI-80 was added dropwise to the dehydrated PPG4000 at a molar ratio of n(NCO) / n(OH) of 2.05 / 1 over two hours at a uniform rate, and the mixture was heated at 75±2℃ and N 2 The reaction is carried out under the following conditions until the NCO content in the synthesized product reaches the theoretical value, thereby obtaining a terminal isocyanate polyurethane prepolymer;

[0087] S2, molar ratio n(NCO) / n(C 2 O) is 1 / 2.05, E51 is added to the isocyanate-terminated polyurethane prepolymer in S1, and 0.1wt% of catalyst-modified imidazole is added, and then heated at 120°C and N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthesized product was ≤0.1%, thereby obtaining the epoxy-terminated polyurethane toughening agent Z1 for bridge and tunnel pavement;

[0088] <Preparation of epoxy-terminated polyurethane binder for bridge and tunnel paving>

[0089] P1. Weigh the above raw materials in the ratio of liquid epoxy: toughening agent Z1: active diluent: coupling agent = 10:80:10:1, and mix them at 60°C with stirring for 1 hour to obtain component A of bridge and tunnel paving material;

[0090] P2. Weigh the above raw materials in order according to the ratio of polyetheramine curing agent D400: low molecular weight polyamide curing agent Versamid 115 = 1:1, and stir and mix at 40° C. for 1 hour to obtain bridge and tunnel paving material component B;

[0091] P3. Weigh the high-toughness epoxy component A and component B of the road and bridge materials in a mass ratio of 3:1, and stir and mix them at room temperature for 2 minutes to obtain the bridge and tunnel paving material binder B1. After curing at RT / 7d, relevant performance tests are carried out. The relevant properties are shown in Table 1.

[0092] <Preparation of epoxy-terminated polyurethane mixture for bridge and tunnel paving>

[0093] P4. The bridge and tunnel paving material binder B1 prepared above was mixed with stone to obtain the bridge and tunnel paving material mixture M1. After curing at RT / 7d, relevant performance tests were carried out. The relevant performances are shown in Table 3.

[0094] Table 3 Performance test data in Example 3

[0095]

[0096] Example 4

[0097] <Preparation of epoxy-terminated polyurethane toughening agent for bridge and tunnel paving>

[0098] S1. Heat PPG4000 at 105℃, N 2 After dehydration for 2 hours under the conditions, TDI-80 is uniformly added dropwise to the dehydrated PPG4000 at a molar ratio of n(NCO) / n(OH) of 2.00 to 2.05 / 1 within two hours, and reacted at 75±2°C and N2 until the NCO content in the synthesized product reaches the theoretical value, thereby obtaining a terminal isocyanate polyurethane prepolymer;

[0099] S2, molar ratio n(NCO) / n(C 2 O) is 1 / 2.00 to 2.05, E51 is added to the isocyanate-terminated polyurethane prepolymer in S1, and 0.1 wt% of catalyst-modified imidazole is added, and then heated at 120°C and N 2 The reaction was carried out under the following conditions until the residual NCO content in the synthesized product was ≤0.1%, thereby obtaining the epoxy-terminated polyurethane toughening agent Z1 for bridge and tunnel pavement;

[0100] <Preparation of epoxy-terminated polyurethane binder for bridge and tunnel paving>

[0101] P1. Weigh the above raw materials in the ratio of liquid epoxy: toughening agent Z1: active diluent: coupling agent = 10:80:10:1, and mix them at 60°C with stirring for 1 hour to obtain component A of bridge and tunnel paving material;

[0102] P2. Weigh the above raw materials in order according to the ratio of polyetheramine curing agent D400: low molecular weight polyamide curing agent Versamid 115 = 1:1, and stir and mix at 40° C. for 1 hour to obtain bridge and tunnel paving material component B;

[0103] P3. Weigh the high-toughness epoxy component A and component B of the road and bridge materials in a mass ratio of 3:1, and stir and mix them at room temperature for 2 minutes to obtain the bridge and tunnel paving material binder B1. After curing at RT / 7d, relevant performance tests are carried out. The relevant properties are shown in Table 1.

[0104] <Preparation of epoxy-terminated polyurethane mixture for bridge and tunnel paving>

[0105] P4. The bridge and tunnel paving material binder B1 prepared above was mixed with stone to obtain the bridge and tunnel paving material mixture M1. After curing at RT / 7d, relevant performance tests were carried out. The relevant performances are shown in Table 3.

[0106] Table 4 Performance test data in Example 4

[0107]

[0108] Comparative Example 1

[0109] Compared with Example 1, the polyurethane toughening agent for bridge and tunnel pavement in this comparative example 1 does not use epoxy compounds to end-cap the polyurethane, and is completely composed of terminal isocyanate polyurethane, and the remaining steps are the same as those in Example 1. Since the polyurethane toughening agent contains highly reactive isocyanate groups, a gel reaction occurs about 10 minutes after it is mixed with an amine curing agent, and the technical requirements for construction and workability of bridge and tunnel pavement cannot be met.

[0110] Table 5 Performance test data in comparative example 1

[0111]

[0112] Comparative Example 2

[0113] Compared with Example 2, in this comparative example 2, the polyurethane toughening agent for bridge and tunnel pavement was modified by epoxy compound end-capping without adding a catalyst, and the formed toughening agent molecular chain did not form a five-membered ring structure. There were a large number of epoxy compounds and isocyanate groups that failed to participate in the reaction in the system, and the end-capping reaction failed to be achieved. When it was mixed with the amine curing agent, a gel reaction occurred about 15 minutes later, which could not meet the technical requirements of bridge and tunnel pavement for construction and workability.

[0114] Table 6 Performance test data in comparative example 2

[0115]

[0116] Comparative Example 3

[0117] Compared with Example 3, the catalyst added when the polyurethane toughening agent for bridge and tunnel pavement in Comparative Example 3 is modified by end-capping with an epoxy compound is unmodified imidazole. Although the addition of the unmodified imidazole catalyst can reduce the activation energy of the reaction between the NCO group and the epoxy group, the temperature at which the two can react is still relatively high. At 120°C, the NCO group and the epoxy group in the system are still difficult to react. There are still a large number of isocyanate groups in the system. When it is mixed with an amine curing agent, a gel reaction occurs in about 25 minutes, which cannot meet the technical requirements of bridge and tunnel pavement for construction and workability.

[0118] Table 7 Performance test data in comparative example 3

[0119]

[0120] Comparative Example 4

[0121] Compared with Example 4, the polyurethane toughening agent for bridge and tunnel pavement in Comparative Example 4 adopts an oxime capping agent. Although the addition of the oxime capping agent can eliminate the NCO group in the system, it cannot form a five-membered ring structure with the polyurethane, and no active epoxy groups are introduced at both ends of the polyurethane. Although the reaction activity of the cured product is reduced, the toughness is poor and the damping temperature range is narrow.

[0122] Table 8 Performance test data in comparative example 4

[0123]

[0124] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement, characterized in that: The toughening agent is prepared by capping the polyurethane prepolymer with the epoxy group of the epoxy compound under the catalytic action of nano-modified imidazole; Wherein, the NCO group at the end of the polyurethane prepolymer preferentially reacts with the epoxy group under the action of the nano-modified imidazole, and a five-membered ring structure is introduced into the polyurethane molecular chain.

2. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 1, characterized in that: During the reaction, the molar ratio of the epoxy group to the NCO group at the end of the polyurethane prepolymer is 2.00-2.05:

1.

3. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 1, characterized in that: The epoxy compound is one or more of E55, E51 and E44.

4. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 1, characterized in that: The polyurethane prepolymer is prepared by reacting polyisocyanate and polyether polyol, and the molar ratio of NCO groups in the polyisocyanate to OH groups in the polyether polyol is 2.00-2.05:

1.

5. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 4, characterized in that: The polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polytetramethylene glycol.

6. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 4, characterized in that: The polyisocyanate is one or more of TDI, MDI and HDI.

7. The epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 1, characterized in that: The dosage of the nano-modified imidazole is 0.1wt%-0.5wt%; wherein the nano-modified imidazole is prepared by loading imidazole onto nanoparticles.

8. The method for preparing an epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to any one of claims 1 to 7, characterized in that: The steps are as follows: S1: placing the dehydrated polyol in a reaction kettle, adding polyisocyanate in proportion, and reacting at 75±2°C and N2 until the NCO content in the synthesized product reaches the target value (1 / 2 of the NCO content at the beginning of the reaction), thereby obtaining an isocyanate-terminated polyurethane prepolymer; S2: adding epoxy compound and nano-modified imidazole into the isocyanate-terminated polyurethane prepolymer in proportion, and then reacting at 120° C. and N2 until the residual NCO content in the synthesized product is ≤0.1%, thereby obtaining an epoxy-terminated polyurethane prepolymer.

9. The method for using the epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to any one of claims 1 to 7, characterized in that: The steps are as follows: P1: Mixing liquid epoxy resin, epoxy-terminated polyurethane toughening agent and other additives to obtain bridge and tunnel paving material component A; P2 stirs and evenly mixes the polyetheramine curing agent and the low molecular weight polyamide curing agent to obtain the bridge and tunnel paving material component B; P3 mixes component A and component B evenly to obtain the bridge and tunnel paving material binder; P4 mixes the binder and graded stone evenly to obtain a mixture of bridge and tunnel paving materials.

10. The method for using the epoxy-terminated polyurethane toughening agent for bridge and tunnel pavement according to claim 9, characterized in that: In step P1, the mass ratio of the liquid epoxy resin, the epoxy-terminated polyurethane toughening agent and other additives is 10-20:70-80:10-15.

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