Underwater epoxy adhesive for pipeline repair and preparation method thereof

Abstract

The invention relates to an underwater epoxy adhesive for pipeline repair and a preparation method thereof, and belongs to the technical field of epoxy adhesives. In order to solve the problem that the bonding strength of a bionic adhesive cannot meet the requirements of pipeline repair adhesives, the invention provides an underwater epoxy adhesive for pipeline repair, the underwater epoxy adhesive for pipeline repair comprises a component A and a component B in a mass ratio of (1.0-1.5): 1, the component A is composed of epoxy resin and a toughening agent in a mass ratio of 100: (10-50), and the component B is composed of a component C and a component B in a mass ratio of 100: (10-50). And the component B is composed of a curing agent and a filler in a mass ratio of 1: (1-5). An amine compound is modified through biomimetic synthesis, an epoxy curing agent capable of being cured underwater is prepared, then epoxy resin, a flexibilizer, filler and the like are evenly mixed with the curing agent, and the epoxy adhesive is prepared. The epoxy adhesive prepared through a solvent-free method is low in toxicity and free of pollution in the using process, the underwater bonding strength is larger than or equal to 1.5 MPa, and a pipeline can resist 0.4 MPa dynamic water pressure after being repaired.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy adhesives, and in particular relates to an underwater epoxy adhesive for pipeline repair and a preparation method thereof. Background Art

[0002] Underwater pipelines can develop cracks, holes, and other damage due to long-term underwater corrosion, physical wear, or accidental impacts. Damaged pipes or loose joints can lead to leakage, impacting proper transport. While traditional methods for repairing underwater pipelines, such as welding or mechanical clamp installation, are effective, they are complex and costly. Therefore, underwater bonding technology has become an important research area, but its application still faces technical challenges.

[0003] When water submerges a substrate, the adhesive competitively adsorbs with the water, forming an interfacial hydration layer that prevents the adhesive from spreading and curing on the substrate surface. While synthetic adhesives are generally ineffective underwater, nature offers a wealth of underwater adhesives. Oysters, barnacles, seaweed, and tubeworms are ubiquitous on beach rocks, each of which adheres to the rock by secreting specialized adhesives. Mussels, in particular, have garnered significant attention for their exceptional hydroadhesive properties. Mussel foot protein (Mfp), secreted by their foot glands, contains a significant amount of 3,4-dihydroxyphenylalanine (DOPA). DOPA's catechol groups achieve underwater bond strengths exceeding 10 MPa through multiple interactions, including metal coordination, hydrogen bonding, and covalent crosslinking. Inspired by this, the development of biomimetic adhesives has become a hot topic. Researchers typically replace protein backbones with synthetic polymers and mimic the adhesion chemistry of DOPA by grafting catechol derivatives. However, the bond strengths of these biomimetic adhesives are generally ≤1 MPa, failing to meet the requirements for pipeline repair adhesives. Summary of the Invention

[0004] In order to solve the problem that the bonding strength of bionic adhesives cannot meet the requirements of adhesives for pipeline repair, the present invention provides an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

[0005] The technical solution of the present invention:

[0006] An underwater epoxy adhesive for pipeline repair comprises a component A and a component B, wherein the mass ratio of the components A and B is (1.0-1.5):1; the component A comprises an epoxy resin and a toughening agent, wherein the mass ratio of the epoxy resin and the toughening agent is 100:(10-50); the component B comprises a curing agent and a filler, wherein the mass ratio of the epoxy curing agent to the filler is 1:(1-5);

[0007] The preparation method of the epoxy curing agent comprises the following steps: adding an amine compound and a phenol compound into a container equipped with a stirrer and purged with nitrogen, maintaining the system temperature at 50-65°C, allowing the amine compound to completely dissolve and be fully mixed with the phenol compound; adding an aldehyde compound into the reaction system, maintaining the system temperature at 55-75°C during the addition process, raising the temperature of the resulting mixed system to 80-100°C after the addition is completed and maintaining the temperature until the reaction is completed, and removing water by reduced pressure distillation to obtain the epoxy curing agent.

[0008] Furthermore, the epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin; the toughening agent is one or a combination of liquid nitrile rubber, carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, amine-terminated liquid nitrile rubber, liquid chloroprene rubber, hydroxyl silicone rubber, polyethylene glycol or polyurethane prepolymer.

[0009] Furthermore, the epoxy resin is bisphenol A epoxy resin E-44 and / or E-51.

[0010] Furthermore, the phenolic compound used to prepare the epoxy curing agent is dihydric phenol and its modified phenol, the amine compound is a combination of one or more of diamine, triamine or tetraamine; the aldehyde compound is formaldehyde and / or formal; and the molar ratio of the phenolic compound, the amine compound and the aldehyde compound is (0.5-1.2):(0.5-1.2):(0.9-1.1).

[0011] Furthermore, the phenolic compound used to prepare the epoxy curing agent is catechol, which includes catechol, resorcinol, hydroquinone or modified phenols thereof; the amine compound is aliphatic amine or aromatic amine, the aliphatic amine is diethylenetriamine, triethylenetetramine or tetraethylenepentamine, and the aromatic amine is phenylenediamine.

[0012] Furthermore, when preparing the epoxy curing agent, nitrogen is passed through the reaction process to isolate the air, the mixing temperature of the amine compound and the phenolic compound is 55~60°C, the reaction temperature of the mixed system is 85~90°C, the reaction time is 4h, and the pressure of the reduced pressure distillation is -0.1MPa.

[0013] Furthermore, the filler is one or a combination of silicon micropowder, mica powder, gas white, carbon nanotubes or graphene; the ethylene silicon micropowder and the mica powder are dried at 110°C for 2 hours before use; the gas white is hydrophobic meteorological silica, the carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes, and the graphene is one or a combination of single-layer graphene, double-layer graphene, few-layer graphene or multi-layer graphene.

[0014] A method for preparing an underwater epoxy adhesive for pipeline repair comprises the following steps:

[0015] Step 1: Stirring the epoxy resin and toughening agent at 100-180° C. for 3 hours to obtain component A;

[0016] Step 2: Stir the epoxy curing agent and filler at room temperature for 1 hour to mix evenly to obtain component B;

[0017] Step 3: When using, mix component A and component B evenly according to the mass ratio at room temperature, and then perform cementation in a dry state or underwater environment.

[0018] Furthermore, the curing time of the adhesive at room temperature is 3 hours, the curing time at 40° C. is 2 hours, and the curing time at 50° C. is 1 hour.

[0019] Furthermore, when bonding under dynamic water pressure, the bonding quality is improved by pressing, and the pressing pressure is 1~100N / cm 3 .

[0020] Beneficial effects of the present invention:

[0021] The present invention modifies low-molecular-weight amine compounds through biomimetic synthesis to prepare an epoxy curing agent that can be cured underwater. The epoxy resin, toughening agent, and filler are then uniformly mixed with the curing agent to prepare an underwater epoxy adhesive for rapid repair. The underwater epoxy adhesive for pipeline repair provided by the present invention is prepared using a solvent-free method. It is low-toxic and pollution-free during use, and is environmentally friendly. Underwater adhesive curing can be completed within 3 hours at room temperature, with an underwater bonding strength of ≥1.5 MPa. After the pipeline is repaired, it can withstand a dynamic water pressure of 0.4 MPa. Therefore, this adhesive not only overcomes the problem of adhesives being difficult to cure underwater, but also provides an adhesive formula that meets the needs of high-strength underwater bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the infrared spectrum of the epoxy curing agent prepared in Example 1;

[0023] Figure 2 Photos of the pipe before and after repair using the epoxy adhesive prepared in Example 1;

[0024] Figure 3 The following are on-site photos of a pressure test after repairing a pipe hole using the epoxy adhesive prepared in Example 1. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the scope of protection of the present invention. The process equipment or devices not specifically noted in the following examples are all conventional equipment or devices in the art. Unless otherwise specified, the raw materials used in the examples of the present invention can be obtained commercially; unless otherwise specified, the technical means used in the examples of the present invention are all conventional means well known to those skilled in the art.

[0026] Example 1

[0027] This embodiment provides an epoxy curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

[0028] The preparation method of the epoxy curing agent in this embodiment is as follows:

[0029] 0.5 mol of catechol was added to a three-necked flask equipped with a stirrer and nitrogen gas, and 0.8 mol of ethylenediamine was slowly added dropwise under a nitrogen atmosphere. The reaction temperature was controlled at 55±5°C and the mixture was reacted for 1 hour until uniform mixing was achieved. The system was heated to 65±5°C and 1 mol of formal was slowly added dropwise. The system temperature was controlled at 85±5°C and maintained for 4 hours. After the system was fully reacted, water was removed by reduced pressure distillation under a pressure of -0.1 MPa to obtain an epoxy curing agent. The infrared spectrum of the epoxy curing agent obtained in this example is shown in FIG. Figure 1 .

[0030] The preparation method of the epoxy adhesive in this embodiment is as follows:

[0031] Step 1: 100g of epoxy resin E-51 and 10g of liquid nitrile rubber were fully reacted at 120°C for 3h and then cooled to room temperature to obtain component A;

[0032] Step 2: Dry 50g of silicon micropowder and 50g of mica powder in an oven at 110°C for 2h and cool to room temperature; take 5g of silicon micropowder, 5g of mica powder, 1g of hydrophobic fumed silica, 3g of single-walled carbon nanotubes, 0.5g of single-layer graphene and 10g of epoxy curing agent and stir them at room temperature for 1h to obtain component B;

[0033] Step 3: When using, fully mix components A and B at a mass ratio of 1.5:1 at room temperature to obtain a liquid epoxy adhesive.

[0034] like Figure 2As shown, the prepared epoxy adhesive was used to repair damaged holes in aluminum alloy pipes. The epoxy adhesive was applied to the hole area of ​​the pipe, ensuring complete coverage. The pipe was then placed in an underwater environment for curing at 23°C for 3 hours. Testing according to GB / T-7124, Determination of Tensile Shear Strength of Adhesives, revealed a bond strength of 2.31 MPa.

[0035] like Figure 3 As shown, when a dynamic water pressure of 0.4 MPa is applied to the aluminum alloy pipe after repair and curing, the repaired part remains intact, indicating that the repaired part after repaired with the epoxy adhesive of this embodiment can withstand a dynamic water pressure of 0.4 MPa.

[0036] Example 2

[0037] This embodiment provides an epoxy curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

[0038] The preparation method of the epoxy curing agent in this embodiment is as follows:

[0039] Add 1 mol of resorcinol into a three-necked flask equipped with a stirrer and purged with nitrogen. Slowly add 1.1 mol of ethylenediamine dropwise under a nitrogen atmosphere. Control the reaction temperature to 55±5°C. React for 1 hour until the mixture is uniformly mixed. Heat the system to 65±5°C and slowly add 1 mol of formal. Control the system temperature to 85±5°C and maintain for 4 hours to allow the system to fully react. Remove water by reduced pressure distillation at a pressure of -0.1 MPa to obtain the epoxy curing agent.

[0040] The preparation method of the epoxy adhesive in this embodiment is as follows:

[0041] Step 1: 100g of epoxy resin E-51 and 10g of liquid nitrile rubber were fully reacted at 120°C for 3h and then cooled to room temperature to obtain component A;

[0042] Step 2: Dry 50g of silicon micropowder and 50g of mica powder in an oven at 110°C for 2h and cool to room temperature; take 5g of silicon micropowder, 5g of mica powder, 1g of hydrophobic fumed silica, 3g of single-walled carbon nanotubes, 0.5g of single-layer graphene and 10g of epoxy curing agent and stir them at room temperature for 1h to obtain component B;

[0043] Step 3: When using, fully mix components A and B at room temperature according to the mass ratio of component A to component B of 1.2:1 to obtain a liquid epoxy adhesive.

[0044] The prepared epoxy adhesive was used to repair damaged holes in aluminum alloy pipes. The adhesive was applied to the hole, ensuring complete coverage. The pipe was then placed underwater to cure at 23°C for 3 hours. Testing according to GB / T-7124, Determination of Tensile Shear Strength of Adhesives, revealed a bond strength of 3.06 MPa.

[0045] Example 3

[0046] This embodiment provides an epoxy curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

[0047] The preparation method of the epoxy curing agent in this embodiment is as follows:

[0048] Add 1 mol of hydroquinone into a three-necked flask equipped with a stirrer and purged with nitrogen. Slowly add 1.1 mol of ethylenediamine dropwise under a nitrogen atmosphere. Control the reaction temperature to 55±5°C. React for 1 hour until the mixture is uniformly mixed. Heat the system to 65±5°C and slowly add 1 mol of formal. Control the system temperature to 85±5°C and maintain for 4 hours to allow the system to fully react. Remove water by reduced pressure distillation at a pressure of -0.1 MPa to obtain the epoxy curing agent.

[0049] The preparation method of the epoxy adhesive in this embodiment is as follows:

[0050] Step 1: 100g of epoxy resin E-51 and 10g of liquid nitrile rubber were fully reacted at 120°C for 3h and then cooled to room temperature to obtain component A;

[0051] Step 2: Dry 50g of silicon micropowder and 50g of mica powder in an oven at 110°C for 2h and cool to room temperature; take 5g of silicon micropowder, 5g of mica powder, 1g of hydrophobic fumed silica, 3g of single-walled carbon nanotubes, 0.5g of single-layer graphene and 10g of epoxy curing agent and stir them at room temperature for 1h to obtain component B;

[0052] Step 3: When using, fully mix components A and B at a mass ratio of 1:1 at room temperature to obtain a liquid epoxy adhesive.

[0053] The prepared epoxy adhesive was used to repair damaged holes in aluminum alloy pipes. The adhesive was applied to the hole, ensuring complete coverage. The pipe was then placed underwater to cure at 23°C for 3 hours. Testing according to GB / T-7124, Determination of Tensile Shear Strength of Adhesives, revealed a bond strength of 1.98 MPa.

Claims

1. An underwater epoxy adhesive for pipeline repair, characterized in that: The invention comprises a component A and a component B, wherein the mass ratio of the component A to the component B is (1.0-1.5):1; the component A is composed of an epoxy resin and a toughening agent, wherein the mass ratio of the epoxy resin to the toughening agent is 100:(10-50); the component B is composed of a curing agent and a filler, wherein the mass ratio of the epoxy curing agent to the filler is 1:(1-5); The preparation method of the epoxy curing agent comprises the following steps: adding an amine compound and a phenol compound into a container equipped with a stirrer and purged with nitrogen, maintaining the system temperature at 50-65°C, allowing the amine compound to completely dissolve and be fully mixed with the phenol compound; adding an aldehyde compound into the reaction system, maintaining the system temperature at 55-75°C during the addition process, raising the temperature of the resulting mixed system to 80-100°C after the addition is completed and maintaining the temperature until the reaction is completed, and removing water by reduced pressure distillation to obtain the epoxy curing agent.

2. The underwater epoxy adhesive for pipeline repair according to claim 1, characterized in that: The epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin; the toughening agent is one or a combination of liquid nitrile rubber, carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, amine-terminated liquid nitrile rubber, liquid chloroprene rubber, hydroxyl silicone rubber, polyethylene glycol or polyurethane prepolymer.

3. The underwater epoxy adhesive for pipeline repair according to claim 2, characterized in that: The epoxy resin is bisphenol A type epoxy resin E-44 and / or E-51.

4. The underwater epoxy adhesive for pipeline repair according to any one of claims 1 to 3, characterized in that: The phenolic compound used in preparing the epoxy curing agent is dihydric phenol and its modified phenol, the amine compound is a combination of one or more of diamine, triamine or tetraamine; the aldehyde compound is formaldehyde and / or formal; and the molar ratio of the phenolic compound, the amine compound and the aldehyde compound is (0.5-1.2):(0.5-1.2):(0.9-1.1).

5. The underwater epoxy adhesive for pipeline repair according to claim 4, characterized in that: The phenolic compound used to prepare the epoxy curing agent is catechol, which includes catechol, resorcinol, hydroquinone or modified phenols thereof; the amine compound is aliphatic amine or aromatic amine, the aliphatic amine is diethylenetriamine, triethylenetetramine or tetraethylenepentamine, and the aromatic amine is phenylenediamine.

6. The underwater epoxy adhesive for pipeline repair according to claim 5, characterized in that: When preparing the epoxy curing agent, nitrogen is passed through the reaction process to isolate the air, the mixing temperature of the amine compound and the phenol compound is 55-60°C, the reaction temperature of the mixed system is 85-90°C, the reaction time is 4 hours, and the pressure of the reduced pressure distillation is -0.1 MPa.

7. The underwater epoxy adhesive for pipeline repair according to claim 5, characterized in that: The filler is one or a combination of silicon micropowder, mica powder, gas white, carbon nanotubes or graphene; the ethylene silicon micropowder and the mica powder are dried at 110°C for 2 hours before use; the gas white is hydrophobic meteorological silica, the carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes, and the graphene is one or a combination of single-layer graphene, double-layer graphene, few-layer graphene or multi-layer graphene.

8. A method for preparing the underwater epoxy adhesive for pipeline repair according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: Stirring the epoxy resin and toughening agent at 100-180° C. for 3 hours to obtain component A; Step 2: Stir the epoxy curing agent and filler at room temperature for 1 hour to mix evenly to obtain component B; Step 3: When using, mix component A and component B evenly according to the mass ratio at room temperature, and then perform cementation in a dry state or underwater environment.

9. The method for preparing the underwater epoxy adhesive for pipeline repair according to claim 8, characterized in that: The curing time of the adhesive at room temperature is 3 hours, the curing time at 40°C is 2 hours, and the curing time at 50°C is 1 hour.

10. The method for preparing the underwater epoxy adhesive for pipeline repair according to claim 9, characterized in that: When bonding under dynamic water pressure, the bonding quality is improved by pressing, and the pressing pressure is 1~100N / cm 3 .

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