Underwater epoxy adhesive for rapid repair and solvent-free preparation method thereof

Abstract

The invention relates to an underwater epoxy adhesive for rapid repair and a solvent-free preparation method thereof, and belongs to the technical field of epoxy adhesives. In order to solve the problems of insufficient bonding strength and environmental pollution of the existing underwater adhesive, the invention provides an underwater epoxy adhesive for rapid repair, which is prepared from a component A and a component B in a mass ratio of (1.5-2.5): 1, the component A is composed of epoxy resin and a flexibilizer in a mass ratio of 100: (10-50), and the component B is composed of an underwater adhesive curing agent and a filler in a mass ratio of 1: (1-3). The preparation method comprises the following steps: firstly, modifying a low-molecular amine compound by using formaldehyde or formal to prepare an underwater adhesive curing agent, and then uniformly mixing the underwater adhesive curing agent with the epoxy resin, the flexibilizer and the filler to prepare the underwater epoxy adhesive. 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 MPa, and the epoxy adhesive can resist 0.5 MPa dynamic water pressure after a pipeline is repaired.

Description

Technical Field

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

[0002] When ships navigate the harsh environments of rivers, streams, and seas, they inevitably suffer damage and corrosion. Furthermore, offshore bridges, subsea tunnels, and submarine pipelines, exposed to the marine environment for extended periods, are also subject to corrosion, shortening their service life. Currently, repairing corrosion or cracks on ships typically requires towing them back to dock for repairs. Repairing corrosion, cracks, and even leaks in subsea pipelines and tunnels primarily relies on manual submersibles. These traditional repair methods are not only labor-intensive and time-consuming, but also significantly reduce a ship's service life.

[0003] In daily life, drainage pipes, heating pipes and other facilities often leak after being used for a period of time. The current solution usually requires first depressurizing and draining the water, and then replacing or gluing the leaking pipes. This type of operation is not only cumbersome, but also affects the normal lives of residents. Although adhesives can be avoided as much as possible from contact with water in daily environments, for special scenarios such as ships and warships, underground water pipelines, etc., it takes a lot of manpower and material resources to completely remove moisture from the surface of the adherend. However, existing commercially available adhesives generally require the surface of the adherend to be dry, and it is difficult to complete curing underwater. In addition, the bonding strength of underwater adhesives developed in the laboratory mostly remains at the hPa level, which cannot meet the actual needs of high-strength underwater bonding.

[0004] It's worth noting that the current solvent preparation process for epoxy adhesives presents environmental challenges. Many traditional formulations still rely on volatile organic compounds (VOCs) or toxic solvents (such as benzene and ketones), which not only pollute the environment but also pose health risks to construction workers. For example, some epoxy resin adhesives release harmful gases such as formaldehyde during the curing process, while the production of polyurethane adhesives may involve highly hazardous raw materials such as isocyanates. Despite progress in underwater epoxy adhesives, their industrial production still faces challenges with high energy consumption and emissions. Summary of the Invention

[0005] In order to solve the problems of insufficient bonding strength and environmental pollution of existing underwater adhesives, the present invention provides an underwater epoxy adhesive for rapid repair and a solvent-free preparation method thereof.

[0006] The technical solution of the present invention:

[0007] A rapid repair underwater epoxy adhesive, comprising a component A and a component B in a mass ratio of (1.5-2.5):1, wherein the component A comprises an epoxy resin and a toughening agent in a mass ratio of 100:(10-50), and the component B comprises an underwater adhesive curing agent and a filler in a mass ratio of 1:(1-3);

[0008] The preparation method of the underwater adhesive curing agent is:

[0009] An amine compound and a phenol compound are added to a container equipped with stirring and nitrogen flow, and the system temperature is maintained at 60-70°C to completely dissolve the amine compound and fully mix with the phenol compound; an aldehyde compound is added to the reaction system, and the system temperature is maintained at 60-80°C during the addition process. After the addition is completed, the temperature of the obtained mixed system is raised to 90-110°C and maintained until the reaction is completed, and water is removed by reduced pressure distillation to obtain an underwater adhesive curing agent.

[0010] 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.

[0011] Furthermore, the epoxy resin is bisphenol A epoxy resin E-44 and / or E-51.

[0012] Furthermore, the phenolic compound used to prepare the epoxy curing agent is monophenol 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 (0.8-1.2):(0.8-1.2):(0.9-1.1).

[0013] Furthermore, the phenolic compound used to prepare the epoxy curing agent is phenol or a modified phenol thereof; the amine compound is an aliphatic amine or an aromatic amine, the aliphatic amine is diethylenetriamine, triethylenetetramine or tetraethylenepentamine, and the aromatic amine is phenylenediamine.

[0014] Furthermore, when preparing the epoxy curing agent, nitrogen was passed through the reaction process to isolate the air, and the pressure of the reduced pressure distillation was -0.1 MPa.

[0015] 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.

[0016] A method for preparing an underwater epoxy adhesive for rapid repair, comprising the following steps:

[0017] Step 1: Stir the epoxy resin and toughening agent at 100-180° C. for 3 hours to obtain component A;

[0018] Step 2: Stir the epoxy curing agent and filler at room temperature for 1 hour to mix evenly to obtain component B;

[0019] 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.

[0020] Furthermore, the curing time of the adhesive bonding at room temperature is 4 hours, the curing time at 60° C. is 2 hours, and the curing time at 80° C. is 1 hour.

[0021] Furthermore, when bonding under dynamic water pressure, the bonding quality is improved by pressing, and the pressing pressure is 1~100N / cm 3 .

[0022] Beneficial effects of the present invention:

[0023] The present invention first uses formaldehyde or formal to modify low-molecular-weight amine compounds to prepare an underwater adhesive curing agent that can be cured underwater. Then, epoxy resin, toughening agent, filler, etc. are uniformly mixed with the underwater adhesive curing agent to prepare an underwater epoxy adhesive for rapid repair. The present invention uses a solvent-free method to prepare the underwater epoxy adhesive. The use process is low-toxic and pollution-free. Underwater bonding and curing can be completed in 4 hours at room temperature. The underwater bonding strength is ≥1 MPa, and the pipeline can withstand a dynamic water pressure of 0.5 MPa after repair. Therefore, this adhesive not only makes up for the problem that adhesives are difficult to cure underwater, but also provides an adhesive formula that meets the needs of high-strength underwater bonding. It is not only of great significance to improving the maintenance efficiency of ships and marine infrastructure, but also can reduce interference with residents' lives and promote the advancement of green manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the infrared spectrum of the underwater adhesive curing agent prepared in Example 1;

[0025] Figure 2This is a DSC curve diagram of the underwater adhesive prepared in Example 3;

[0026] Figure 3 This is a comparison chart of the bonding strength of the underwater adhesives prepared in Example 1, Example 2 and Example 3 in dry state, underwater and simulated seawater environment. DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1

[0029] This embodiment provides an underwater adhesive curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

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

[0031] 1 mol of phenol was added to a three-necked flask equipped with a stirrer and nitrogen gas, and 1 mol of ethylenediamine was slowly added dropwise under a nitrogen atmosphere. The reaction temperature was controlled at 65±5°C and the reaction was continued for 1 hour until the mixture was uniform. The system was heated to 75±5°C and 1 mol of formal was slowly added dropwise. The system temperature was controlled at 95±5°C and maintained for 4 hours. After the system was fully reacted, water was removed by vacuum 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 , its molecular structure diagram is shown in Formula I:

[0032]

[0033] Formula I.

[0034] The preparation method of the underwater epoxy adhesive in this embodiment is as follows:

[0035] 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;

[0036] 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 underwater adhesive curing agent and stir them at room temperature for 1h to mix evenly to obtain component B;

[0037] Step 3: When using, fully mix components A and B at a mass ratio of 2:1 at room temperature to obtain a viscous liquid underwater epoxy adhesive.

[0038] Example 2

[0039] This embodiment provides an underwater adhesive curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

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

[0041] Add 1 mol of phenol to a three-necked flask equipped with a stirrer and nitrogen gas, slowly add 1.1 mol of ethylenediamine dropwise under a nitrogen atmosphere, control the reaction temperature to 65±5°C, react for 1 hour until the mixture is uniformly mixed, heat the system to 75±5°C and slowly add 1 mol of formal, control the system temperature to 95±5°C and maintain for 4 hours to allow the system to fully react, and then remove water by reduced pressure distillation at a pressure of -0.1 MPa to obtain the epoxy curing agent.

[0042] The preparation method of the underwater epoxy adhesive in this embodiment is as follows:

[0043] 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;

[0044] 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 underwater adhesive curing agent and stir them at room temperature for 1h to mix evenly to obtain component B;

[0045] Step 3: When using, fully mix components A and B at a mass ratio of 2:1 at room temperature to obtain a viscous liquid underwater epoxy adhesive.

[0046] Example 3

[0047] This embodiment provides an underwater adhesive curing agent and an underwater epoxy adhesive for pipeline repair and a preparation method thereof.

[0048] The preparation method of the underwater adhesive curing agent in this embodiment is as follows:

[0049] Add 1 mol of phenol to a three-necked flask equipped with a stirrer and nitrogen gas, slowly add 1.1 mol of ethylenediamine dropwise under a nitrogen atmosphere, control the reaction temperature to 65±5°C, react for 1 hour until the mixture is uniformly mixed, heat the system to 75±5°C and slowly add 1 mol of formal, control the system temperature to 95±5°C and maintain for 4 hours to allow the system to fully react, and then remove water by reduced pressure distillation at a pressure of -0.1 MPa to obtain the epoxy curing agent.

[0050] The preparation method of the underwater epoxy adhesive in this embodiment is as follows:

[0051] 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;

[0052] 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 underwater adhesive curing agent and stir them at room temperature for 1h to mix evenly to obtain component B;

[0053] 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 1.9:1 to obtain a viscous liquid underwater epoxy adhesive. The DSC curve of the underwater epoxy adhesive obtained in this embodiment is as follows: Figure 2 shown.

[0054] The underwater epoxy adhesives prepared in Examples 1, 2, and 3 were respectively bonded to aluminum alloys and cured in a dry state, an underwater environment, and a simulated seawater environment, respectively, at a temperature of 23°C for 4 hours. The adhesive strength of the epoxy adhesives was measured according to the method for determining the tensile shear strength of adhesives in accordance with GB / T-7124. Figure 3 As shown, the bonding strengths of the underwater epoxy adhesives of Example 1, Example 2 and Example 3 in the dry state are 5.17 MPa, 4.32 MPa and 1.55 MPa, respectively; the bonding strengths in the underwater environment are 11.08 MPa, 3.93 MPa and 0.71 MPa, respectively; and the bonding strengths in the simulated seawater environment are 14.63 MPa, 1.08 MPa and 0.96 MPa, respectively.

Claims

1. A rapid repair underwater epoxy adhesive, characterized in that: The invention is prepared from component A and component B in a mass ratio of (1.5-2.5):1, wherein the component A is composed of an epoxy resin and a toughening agent in a mass ratio of 100:(10-50), and the component B is composed of an underwater adhesive curing agent and a filler in a mass ratio of 1:(1-3); The preparation method of the underwater adhesive curing agent is: An amine compound and a phenol compound are added to a container equipped with stirring and nitrogen flow, and the system temperature is maintained at 60-70°C to completely dissolve the amine compound and fully mix with the phenol compound; an aldehyde compound is added to the reaction system, and the system temperature is maintained at 60-80°C during the addition process. After the addition is completed, the temperature of the obtained mixed system is raised to 90-110°C and maintained until the reaction is completed, and water is removed by reduced pressure distillation to obtain an underwater adhesive curing agent.

2. The underwater epoxy adhesive for rapid 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 rapid 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 rapid repair underwater epoxy adhesive according to any one of claims 1 to 3, characterized in that: The phenolic compound used in preparing the epoxy curing agent is monophenol 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 (0.8-1.2):(0.8-1.2):(0.9-1.1).

5. The underwater epoxy adhesive for rapid repair according to claim 4, characterized in that: The phenolic compound used in preparing the epoxy curing agent is phenol or a modified phenol 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 rapid repair according to claim 5, characterized in that: When preparing the epoxy curing agent, nitrogen was passed through the reaction process to isolate the air, and the pressure of the reduced pressure distillation was -0.1 MPa.

7. The underwater epoxy adhesive for rapid repair according to claim 6, 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 rapid repair according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: Stir 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 rapid repair according to claim 8, characterized in that: The curing time of the adhesive at room temperature is 4 hours, the curing time at 60° C. is 2 hours, and the curing time at 80° C. is 1 hour.

10. The method for preparing the underwater epoxy adhesive for rapid 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 .

Images