Fast-curing epoxy resin adhesive as well as preparation method and application thereof

Abstract

The invention relates to the field of C09J163 / 00, in particular to a fast-curing epoxy resin adhesive and a preparation method and application thereof. The fast-curing epoxy resin adhesive is composed of a component A and a component B, the component A at least comprises the following preparation raw materials: epoxy resin, a filler A, a diluent, a flexibilizer and a coupling agent A; the component B at least comprises the following preparation raw materials: a curing agent, a filler B, an accelerant and a coupling agent B; the curing agent is a combination of a polythiol curing agent and at least one of a phenolic aldehyde amine curing agent and a polyamide curing agent, by optimizing a formula system, the operable time (pot life), the curing speed and the hardness after curing of the product are effectively balanced, the product is rapidly cured within the proper operable time, the hardness after curing can be guaranteed, and the service life of the product is prolonged. And the actual application requirements of pipeline cold welding emergency repair are met.

Description

Technical Field

[0001] The invention relates to the field of C09J163 / 00, and in particular to a fast-curing epoxy resin adhesive and a preparation method and application thereof. Background Art

[0002] "Cold welding" bonding technology is also called chemical bonding technology. It refers to a new technology that uses chemical bonding materials (adhesives, sealants, retainers, repair agents, etc.) to achieve connection, sealing, retention, and functional coating. "Cold welding" repair technology originated from the early use of composite materials to repair aircraft, and was later extended to the repair of metal pipes in factories. Chemical metal pipelines are prone to corrosion due to long-term exposure to chemical plant environments. Generally speaking, they are divided into internal corrosion and external corrosion. External corrosion is generally due to the influence of pipeline materials and the external environment, including chemical corrosion, electrochemical corrosion, bacterial corrosion, etc. Internal corrosion is affected by the relationship between the pipeline transportation medium and the medium flow rate, which causes damage to the pipeline in the long run. Both external corrosion and internal corrosion will cause damage to the pipeline, and in severe cases, leakage or even shutdown. Therefore, timely maintenance and plugging of pipelines are crucial to chemical production and safety.

[0003] Among the several methods currently used to plug leaks in metal pipes, using epoxy metal plugging glue for repair is the most convenient and economical way. Epoxy resin has the advantages of small shrinkage, good mechanical properties after curing, acid and alkali resistance, not easy to age, and strong adhesion to metal. As a metal repair agent, it can meet the use requirements and is economical. However, the curing time of the existing metal repair AB glue on the market is relatively long (10min to 30min), which makes it difficult to fix the repair tooling during the emergency repair process to achieve the effect of emergency repair. A Chinese patent (authorization announcement number CN103555245B) discloses an epoxy adhesive for hinged joint repair and reinforcement and its application, which can form effective bonding and strength in a shorter period of time, and its product application period is 30-45min. A Chinese patent (authorization announcement number CN106496944B) discloses a high-toughness hand-layup epoxy resin composition for wind turbine blades and its preparation method, which meets the actual construction requirements of large-scale wind turbine blade component production or reinforcement by adding toughening agents and modifiers. The product has an operating time of 90-98 minutes, a gel time of 100-113 minutes, and a curing time of 115-124 minutes. Therefore, it cannot meet the actual application requirements of emergency repair of pipeline cold welding. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a fast-curing epoxy resin adhesive, which effectively balances the product's operable time (applicable period), curing speed and hardness after curing by optimizing the formula system. It can quickly cure while maintaining a suitable operable time and ensure the hardness after curing, thereby meeting the actual application needs of emergency repair of pipeline cold welding.

[0005] On one hand, the present invention provides a fast-curing epoxy resin adhesive, which consists of a component A and a component B; the raw materials for preparing the component A at least include: epoxy resin, filler A, diluent, toughening agent, coupling agent A; the raw materials for preparing the component B at least include: curing agent, filler B, accelerator, coupling agent B; the curing agent is a combination of a polythiol curing agent and at least one of a phenolic amine curing agent and a polyamide curing agent.

[0006] As a preferred technical solution, the raw materials for preparing component A include at least 100-150 parts of epoxy resin, 10-40 parts of filler A, 2-10 parts of diluent, 1-8 parts of toughening agent, and 0.1-3 parts of coupling agent A, by weight.

[0007] As a preferred technical solution, the raw materials for preparing the B component include at least 60-120 parts of a curing agent, 5-30 parts of a filler B, 1-8 parts of an accelerator, and 0.1-3 parts of a coupling agent B, by weight.

[0008] As a preferred technical solution, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and novolac epoxy resin.

[0009] Preferably, the viscosity of the epoxy resin (determined by the single cylinder rotation viscometer method in the determination of adhesive viscosity in GB / T2794-2022, the measurement conditions are: temperature 25°C, and the difference between two consecutive test readings is less than 3%) is ≥20000 mPa·s, preferably ≥30000 mPa·s, and more preferably 40000-60000 mPa·s.

[0010] Preferably, the phenolic epoxy resin is F51 and / or F44.

[0011] As a preferred technical solution, the mass ratio of the epoxy resin to the diluent is (20-30):1.

[0012] As a preferred technical solution, the filler A at least includes modified glass flakes.

[0013] Preferably, the particle size of the modified glass flakes is 200-1000 mesh, preferably 300-600 mesh.

[0014] Preferably, the preparation method of the modified glass flakes includes at least the following steps: drying the glass flakes and adding them into a container, adding ethanol into the container and stirring for alcoholization, then dropping an acidic solution into the container to adjust the pH, then dropping a modifier, continuing to stir and then slowly heating and drying.

[0015] Preferably, the mass ratio of the modifier to the glass flakes is 1:(40-60), preferably 1:50.

[0016] Preferably, the modifier is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0017] Preferably, the volume ratio of the mass of the glass flakes to ethanol is (100-150 g): (150-180 mL).

[0018] Preferably, the stirring alcoholization time is 1-3 hours, preferably 2 hours.

[0019] Preferably, the stirring time is 3-5 hours, preferably 4 hours.

[0020] Preferably, the pH is 3-5, preferably 4.

[0021] Preferably, the acidic solution is at least one of an aqueous oxalic acid solution, an aqueous citric acid solution, and an aqueous acetic acid solution, preferably a 2-10 wt % aqueous oxalic acid solution.

[0022] Preferably, the filler A also includes at least one of kaolin, titanium dioxide, quartz powder, graphite, fumed silica, and silicon carbide.

[0023] As a preferred technical solution, the filler A is a combination of modified glass flakes, kaolin and silicon carbide.

[0024] Preferably, the particle size of the kaolin is 500-1000 mesh, and the particle size of the silicon carbide is 100-400 mesh.

[0025] Preferably, the particle size of the kaolin is 800 mesh, and the particle size of the silicon carbide is 800 mesh.

[0026] Preferably, the mass ratio of the modified glass flakes, kaolin and silicon carbide is (5-15):(5-15):(3-10), preferably 10:10:(5-8).

[0027] As a preferred technical solution, the coupling agent A is selected from at least one of KH-560, KH-780, and KH-561, preferably KH-560.

[0028] As a preferred technical solution, the diluent is selected from at least one of 1,4-butanediol glycidyl ether, n-butyl glycidyl ether, allyl glycidyl ether, and diglycidyl ether, preferably 1,4-butanediol glycidyl ether.

[0029] As a preferred technical solution, the toughening agent is selected from at least one of dibutyl phthalate and epoxy-terminated liquid nitrile rubber, preferably dibutyl phthalate.

[0030] As a preferred technical solution, the curing agent is a combination of a polythiol curing agent and a phenalkamine curing agent.

[0031] Preferably, the mass ratio of the polythiol curing agent to the phenalkamine curing agent is (70-100):(3-15), preferably (80-90):(5-10).

[0032] Preferably, the polythiol curing agent is selected from at least one of TSG-9018, TSG-9018T, WSG-522, ZJ-8005, and ZJ-8005-H. Preferably, it is at least one of TSG-9018, TSG-9018T, ZJ-8005, and ZJ-8005-H.

[0033] Preferably, the phenalkamine curing agent is T-31 phenalkamine curing agent.

[0034] As a preferred technical solution, the filler B is selected from at least one of kaolin, quartz powder, titanium dioxide, and fumed silica, preferably a combination of silica and titanium dioxide.

[0035] Preferably, the particle size of the silicon dioxide is 800-1500 mesh, preferably 1000 mesh.

[0036] Preferably, the particle size of the titanium dioxide is 200-400 mesh, preferably 325 mesh.

[0037] As a preferred technical solution, the accelerator is at least one of a tertiary amine accelerator, a substituted urea accelerator, a phenol accelerator, and an imidazole accelerator, preferably a tertiary amine accelerator.

[0038] Preferably, the tertiary amine accelerator is selected from 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), benzyldimethylamine (BDMA), triethylamine, triethanolamine, and o-hydroxybenzyldimethylamine (DMP-10).

[0039] As a preferred technical solution, the coupling agent B is an aminosilane coupling agent, preferably KH-550.

[0040] The actual application conditions of pipeline cold welding repair are relatively harsh, especially the need to directly contact the transport medium, especially acidic or alkaline liquids, and the comprehensive performance requirements of the adhesive are relatively high. In the early stage of the present invention, bisphenol F epoxy resin with low viscosity was used as the main film-forming material, but it could not meet the deployment requirements of casting glue with high viscosity. Therefore, by using phenolic epoxy resin with a viscosity of ≥20000mPa·s, the toughening agent and other raw materials in the system are matched to ensure the acid and alkali resistance, heat resistance and mechanical properties of the adhesive after curing, so as to meet the actual application requirements. Furthermore, the present invention introduces 1,4-butanediol glycidyl ether as a diluent, and controls the mass ratio of the epoxy resin to the diluent to be (20-30):1, thereby overcoming the problem that the phenolic epoxy resin in the system has a large viscosity at low temperatures that affects processing, and while achieving a dilution effect, effectively ensuring that the mechanical properties and the curing speed will not be slowed down. When other diluents or epoxy resins with lower viscosity (bisphenol F epoxy resin with a viscosity of 2000-5000 mPa·s) are used for compounding, the dilution effect on the phenolic epoxy resin in the system is not obvious, which affects the processing of the product and the comprehensive performance of the product after curing.

[0041] Furthermore, the present invention improves the dimensional stability and water resistance, cold resistance and heat resistance of the adhesive by introducing filler A including modified glass flakes, and also improves the wear resistance, corrosion resistance and sealing ability of the adhesive, thereby further enhancing the bonding ability of the adhesive.

[0042] However, the introduction of fillers affects the curing speed of the product and the curing hardness in a short time. The present invention, by comprehensively controlling the addition amount of fillers and the coordination of curing agent and curing agent accelerator, makes the curing speed of the adhesive provided reach within 5min at room temperature, and the surface hardening is fast after curing (30min reaches the use hardness), and the requirements of fast drying and fast hardening are truly achieved, and it can even be cured at low temperature (below 0 ℃), and its cured product has low shrinkage, high mechanical properties, good adhesion to substrate, excellent water resistance and heat resistance, and can quickly repair leaking pipelines online. Specifically, the present invention adopts polythiocarbol fast curing agent, cooperates tertiary amine accelerator and phenalkamine curing agent to achieve fast curing and low temperature curing, reduces the introduction of fillers in the system on the influence of fast drying and fast hardening, especially adopts at least one polythiocarbol curing agent in TSG-9018, TSG-9018T, ZJ-8005, and ZJ-8005-H, so that the adhesive provided has a suitable operable time and is quickly cured, and the use hardness requirement can be met in a short time.

[0043] In addition, the present invention improves the thixotropy and mechanical properties of the adhesive by controlling the introduction of fumed silica into component B, especially by controlling the particle size combination of fumed silica, titanium dioxide, modified glass flakes, kaolin, and silicon carbide in the system, so that the coating after the A and B components are mixed and cured has a higher density.

[0044] The fast-curing epoxy resin adhesive provided by the present invention has low raw material cost and high production efficiency, is easy to realize large-scale industrial production, can be applied to the on-site rapid repair of most pipelines and the rapid repair of pipelines in low temperature environments in winter, and has extremely high market promotion value.

[0045] Another aspect of the present invention provides a method for preparing a fast curing epoxy resin adhesive, comprising at least the following steps:

[0046] (1) adding epoxy resin to a stirring container and heating it in a water bath to 45-55° C., starting stirring, adding diluent, toughening agent, and coupling agent A at a speed of 800-1500 r / min and stirring for 5-15 minutes; maintaining the speed at 800-1500 r / min, adding filler A to the stirring container and stirring for 10-30 minutes to obtain component A;

[0047] (2) adding a curing agent to a stirring container at 15-30° C., starting stirring, maintaining a speed of 800-1500 r / min, adding an accelerator to the stirring container and stirring for 5-15 minutes, and then adding a coupling agent B; maintaining a speed of 800-1500 r / min, adding a filler B to the stirring container and stirring for 10-30 minutes to obtain a B component;

[0048] (3) When using, mix component A and component B in a volume ratio of 1:1 and stir until the color is consistent.

[0049] As a preferred technical solution, the mixing and stirring time in step (3) is controlled within 1 min.

[0050] A third aspect of the present invention provides an application of a fast-curing epoxy resin adhesive for cold welding repair of pipelines and bonding of metal pipe fittings.

[0051] Specifically, it is used for on-site emergency repair and parking repair of metal pipelines such as transportation pipelines, condensation heat exchange pipelines, etc. in factories. The invention can bond carbon steel within 5 minutes and meet the use requirements within 10 minutes. It can be used in conjunction with carbon steel sheets to carry out emergency repair of leaking pipelines.

[0052] It can also be used for bonding common metal pipes in life, such as the rapid bonding of ordinary water pipes and gas pipes. It can quickly repair small leaks and bond pipe joints within 10 minutes.

[0053] Beneficial Effects

[0054] 1. The present invention provides a fast-curing epoxy resin adhesive, which effectively balances the product's operable time (applicable period), curing speed and hardness after curing by optimizing the formula system. It can quickly cure while maintaining a suitable operable time and ensure the hardness after curing, thus meeting the actual application requirements of emergency repair of cold welding of pipelines.

[0055] 2. The present invention comprehensively controls the amount of filler added and the coordination of the curing agent and the curing agent accelerator, so that the curing speed of the provided adhesive reaches within 5 minutes at room temperature, and the surface hardens quickly after curing (reaching the use hardness in 30 minutes), truly achieving the requirements of fast drying and hardening, and can even be cured at low temperature (below 0°C). The cured product has low shrinkage, high mechanical properties, good bonding performance with the substrate, excellent water resistance and heat resistance, and can quickly repair leaking pipes online.

[0056] 3. The present invention adopts a polythiol fast curing agent, cooperates with a tertiary amine accelerator and a phenolic amine curing agent to achieve fast curing and low-temperature curing, and reduces the influence of the introduction of fillers in the system on fast drying and fast hardening. In particular, at least one polythiol curing agent selected from TSG-9018, TSG-9018T, ZJ-8005, and ZJ-8005-H is adopted, so that the provided adhesive has a suitable operating time and is quickly cured, and can meet the hardness requirements in a short time.

[0057] 4. The present invention improves the dimensional stability and water resistance, cold resistance and heat resistance of the adhesive by introducing filler A including modified glass flakes, and co-introducing kaolin and silicon carbide, and also improves the wear resistance, corrosion resistance and sealing ability of the adhesive, thereby further enhancing the bonding ability of the adhesive.

[0058] 5. The fast-curing epoxy resin adhesive provided by the present invention has low raw material cost and high production efficiency, is easy to realize large-scale industrial production, can be applied to the on-site rapid repair of most pipelines and the rapid repair of pipelines in low temperature environments in winter, and has extremely high market promotion value. DETAILED DESCRIPTION

[0059] Examples 1-6

[0060] On the one hand, Examples 1-6 of the present invention provide a fast-curing epoxy resin adhesive, and the raw materials for its preparation are shown in Table 1 in parts by weight.

[0061]

[0062]

[0063] The preparation method of the modified glass flakes comprises the following steps: drying the glass flakes and adding them into a container, adding ethanol into the container and stirring for alcoholization, then dropping an acidic solution into the container to adjust the pH, then dropping a modifier, continuing stirring and slowly heating and drying.

[0064] The mass ratio of the modifier to the glass flakes is 1:50.

[0065] The modifier is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0066] The ratio of the mass of the glass flakes to the volume of ethanol is 120 g:168 mL.

[0067] The stirring alcoholization time is 2h.

[0068] The stirring time is continued for 4 hours.

[0069] The pH is 4.

[0070] The acidic solution is a 5 wt % oxalic acid aqueous solution.

[0071] On the other hand, embodiments 1-6 of the present invention provide a method for preparing a fast-curing epoxy resin adhesive, comprising the following steps:

[0072] (1) adding epoxy resin to a stirring container and heating it in a water bath to 50° C., starting stirring, adding diluent, toughening agent, and coupling agent A at a speed of 1000 r / min and stirring for 10 min; maintaining the speed at 1000 r / min, adding filler A to the stirring container and stirring for 20 min to obtain component A;

[0073] (2) adding a curing agent to a stirring container at 25° C., starting stirring, maintaining the speed at 1000 r / min, adding an accelerator to the stirring container and stirring for 10 min, and then adding a coupling agent B; maintaining the speed at 1000 r / min, adding filler B to the stirring container and stirring for 20 min to obtain component B;

[0074] (3) When using, mix component A and component B in a volume ratio of 1:1 and stir until the color is consistent.

[0075] The mixing and stirring time in step (3) is controlled within 1 min.

[0076] Performance Testing

[0077] 1. Determination of tensile shear strength of adhesive (GB / T6329-1996): The adhesives provided in Examples 1 and 2 were subjected to tensile shear tests, and the tests were performed 4 times in parallel. The test results were averaged. The results are shown in Table 2.

[0078] Table 2

[0079]

[0080] 2. Gel time and surface drying time (GB / T7123.1-2015): The gel time and surface drying time of the adhesive provided in the embodiment were tested, and the commercially available product Kosaixin cast iron repair agent TS11 was used as a control. The hardness was tested 10 minutes, 30 minutes and 1 hour after coating (five points were tested in parallel, and the test results were averaged). The test results are shown in Table 3.

[0081] Table 3

[0082]

[0083]

Claims

1. A fast curing epoxy resin adhesive, characterized in that: The invention is composed of component A and component B; the raw materials for preparing component A at least include: epoxy resin, filler A, diluent, toughening agent, coupling agent A; the raw materials for preparing component B at least include: curing agent, filler B, accelerator, coupling agent B; the curing agent is a combination of a polythiol curing agent and at least one of a phenolic amine curing agent and a polyamide curing agent.

2. The fast curing epoxy resin adhesive according to claim 1, characterized in that: In parts by weight, the raw materials for preparing component A include at least: 100-150 parts of epoxy resin, 10-40 parts of filler A, 2-10 parts of diluent, 1-8 parts of toughening agent, and 0.1-3 parts of coupling agent A; in parts by weight, the raw materials for preparing component B include at least: 60-120 parts of curing agent, 5-30 parts of filler B, 1-8 parts of accelerator, and 0.1-3 parts of coupling agent B.

3. The fast curing epoxy resin adhesive according to claim 1 or 2, characterized in that: The viscosity of the epoxy resin is ≥20000 mPa·s, and the mass ratio of the epoxy resin to the diluent is (20-30):

1.

4. The fast curing epoxy resin adhesive according to claim 3, characterized in that: The filler A at least includes modified glass flakes, and the particle size of the modified glass flakes is 200-1000 meshes.

5. The fast curing epoxy resin adhesive according to claim 4, characterized in that: The filler A also includes at least one of kaolin, titanium dioxide, quartz powder, graphite, fumed silica, and silicon carbide.

6. The fast curing epoxy resin adhesive according to claim 5, characterized in that: The diluent is selected from at least one of 1,4-butanediol glycidyl ether, n-butyl glycidyl ether, allyl glycidyl ether and diglycidyl ether.

7. The fast curing epoxy resin adhesive according to claim 6, characterized in that: The curing agent is a combination of a polythiol curing agent and a phenalkamine curing agent, and the mass ratio of the polythiol curing agent to the phenalkamine curing agent is (70-100): (3-15).

8. The fast curing epoxy resin adhesive according to claim 7, characterized in that: The accelerator is at least one of a tertiary amine accelerator, a substituted urea accelerator, a phenol accelerator, and an imidazole accelerator.

9. A method for preparing a fast curing epoxy resin adhesive according to any one of claims 1 to 8, characterized in that: At least the following steps are included: (1) adding epoxy resin to a stirring container and heating it in a water bath to 45-55° C., starting stirring, adding diluent, toughening agent, and coupling agent A at a speed of 800-1500 r / min and stirring for 5-15 minutes; maintaining the speed at 800-1500 r / min, adding filler A to the stirring container and stirring for 10-30 minutes to obtain component A; (2) adding a curing agent to a stirring container at 15-30° C., starting stirring, maintaining a speed of 800-1500 r / min, adding an accelerator to the stirring container and stirring for 5-15 minutes, and then adding a coupling agent B; maintaining a speed of 800-1500 r / min, adding a filler B to the stirring container and stirring for 10-30 minutes to obtain a B component; (3) When using, mix component A and component B in a volume ratio of 1:1 and stir until the color is consistent.

10. An application of the fast curing epoxy resin adhesive according to any one of claims 1 to 8, characterized in that: Used for pipeline cold welding repair and metal pipe bonding.

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