Amido amine underwater curing agent for epoxy resin and preparation method thereof

Abstract

The invention discloses an amido amine underwater curing agent for epoxy resin and a preparation method of the amido amine underwater curing agent, and belongs to the field of epoxy resin curing agents. The invention discloses a high-temperature-resistant phenolic resin, which is prepared from the following components in parts by mass: 20 to 50 parts of amine, 20 to 50 parts of single acid, 10 to 40 parts of phenolic compound and 5 to 20 parts of phenolic resin, and the amine is at least one of aliphatic amine, alicyclic amine and aromatic amine. The method comprises the following steps: reacting amine with single acid at high temperature to generate amido amine, and further dehydrating at the temperature to synthesize imidazoline. And the content of imidazoline is controlled through the water yield. And cooling to 120-140 DEG C, and adding the phenolic compound to further react with the phenolic resin. According to the invention, the stability of the imidazoline content is controlled by controlling the water yield of the reaction, and the imidazoline content is the key for solving the underwater bonding performance of the epoxy resin adhesive. The low-temperature curing characteristic and flexibility of the curing agent are improved by introducing different amines, and the curing agent can be better applied to protection, reinforcement and waterproofing of underwater buildings, so that the service life of underwater facilities is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater curing agents, and in particular relates to an amide amine underwater curing agent for epoxy resin and a preparation method thereof, which can be widely used in civil engineering fields such as bridges, tunnels, dams, etc. Background Art

[0002] At present, in the fields of civil engineering, polyamide curing agent, polyetheramine or phenolic amine curing agent is generally used as epoxy resin room temperature curing agent. The advantages of polyamide curing agent are good adhesion and good toughness, but the disadvantages are high viscosity and inconvenient operation. The advantages of polyetheramine are good toughness and good color, but the disadvantages are slow reaction speed and poor underwater adhesion. The advantages of general phenolic amine curing agent are low cost and fast curing speed, but it is relatively brittle and has poor toughness. In addition, most of the polyamide curing agents, polyetheramine curing agents and phenolic amine curing agents on the market have poor underwater adhesion. With the development of marine engineering economy, the development of tunnel engineering, and more and more dam and river maintenance projects, the service life after construction and maintenance is required to be longer, and the requirements for the underwater bonding performance of the curing agent are getting higher and higher. It is more urgent to develop a curing agent that can be cured underwater, is economically feasible, and is easy to operate.

[0003] There are few curing agents on the market that can meet the needs of large-scale underwater curing. The underwater bonding performance and mechanical properties after curing need to be improved. Therefore, even if the current products can be used barely, the guaranteed service life is limited, which leads to increased maintenance costs. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an amide amine underwater curing agent for epoxy resin and a preparation method thereof, which significantly improves the underwater bonding performance and mechanical properties after curing, increases the service life after repair and reinforcement, and reduces maintenance costs.

[0005] The present invention is achieved by providing an amide amine underwater curing agent for epoxy resin, which comprises the following components in parts by mass: 20 to 50 parts of amine, 20 to 50 parts of monoacid, 10 to 40 parts of phenolic compound, and 5 to 20 parts of phenolic resin, wherein the amine is at least one of aliphatic amine, alicyclic amine and aromatic amine.

[0006] The fatty amine is at least one of ethylenediamine, pentanediamine, hexamethylenediamine, 2-methylpentanediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0007] The alicyclic amine may be at least one of HMDA, isophoronediamine and cyclohexanediamine.

[0008] The aromatic amine is at least one of DDM, DETDA or m-xylylenediamine.

[0009] The monoacid is at least one of oleic acid, tall oil fatty acid, and long-chain fatty acid.

[0010] The phenolic compound is at least one of phenol, bisphenol A and cardanol.

[0011] The phenolic resin is a polymer of phenol and formaldehyde.

[0012] A method for preparing the above-mentioned amidoamine underwater curing agent for epoxy resin comprises the following steps:

[0013] (1) Mix the amine and the monoacid evenly, raise the temperature to 190° C.-220° C., stir and react for at least 4 hours, and dehydrate during the reaction, and control the imidazoline content of the product to be 20%-70%;

[0014] (2) The mixture of step (1) is cooled to 120-140° C., a phenolic compound and a phenolic resin are added, the reaction temperature is 120-150° C., and the reaction is performed for 3-5 hours to obtain a brown-yellow transparent liquid amidoamine curing agent.

[0015] The present invention has significant advantages and technical effects: first, when the amide amine is used, the epoxy resin adhesive has good bonding performance when used underwater; second, the polyetheramine flexible chain segment is introduced to improve the flexibility of the final cured product and extend the service life of the colloid; third, the phenolic resin is introduced to modify the curing agent, balance the hydrophilicity and hydrophobicity of the curing agent, thereby better improving the underwater bonding performance, and at the same time improve the water resistance and corrosion resistance of the epoxy resin adhesive cured product, and also extend the service life of the colloid, thereby increasing the service life after repair and reinforcement and reducing maintenance costs. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] The amide-amine underwater curing agent for epoxy resin of the present invention comprises the following components in parts by mass: 20 to 50 parts of amine, 20 to 50 parts of monoacid, 10 to 40 parts of phenolic compound, and 5 to 20 parts of phenolic resin, wherein the amine is at least one of aliphatic amine, alicyclic amine and aromatic amine.

[0018] The fatty amine is at least one of ethylenediamine, pentanediamine, hexamethylenediamine, 2-methylpentanediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0019] The alicyclic amine may be at least one of HMDA, isophoronediamine and cyclohexanediamine.

[0020] The aromatic amine is at least one of DDM, DETDA or m-xylylenediamine.

[0021] The monoacid is at least one of oleic acid, tall oil fatty acid, and long-chain fatty acid.

[0022] The phenolic compound is at least one of phenol, bisphenol A and cardanol.

[0023] The phenolic resin is a polymer of phenol and formaldehyde.

[0024] A method for preparing the above-mentioned amidoamine underwater curing agent for epoxy resin comprises the following steps:

[0025] (1) Mix the amine and the monoacid evenly, raise the temperature to 190° C.-220° C., stir and react for at least 4 hours, and dehydrate during the reaction, and control the imidazoline content of the product to be 20%-70%;

[0026] (2) The mixture of step (1) is cooled to 120-140° C., a phenolic compound and a phenolic resin are added, the reaction temperature is 120-150° C., and the reaction is performed for 3-5 hours to obtain a brown-yellow transparent liquid amidoamine curing agent.

[0027] The present invention adopts one or more of aliphatic amine, alicyclic amine and aromatic amine to react with monoacid to generate amidoamine, and dehydration occurs during the reaction. The content of imidazoline can be controlled by controlling the water output. Imidoline is a key factor in improving underwater bonding strength. The generated amidoamine product containing imidazoline reacts with phenolic compounds and phenolic resin. Controlling the content of imidazoline is a key step in this synthesis process, because the amide reacts with the monoacid to produce imidazoline and water. This reaction is a reversible reaction, so continuous dehydration during the reaction will react in the direction of producing imidazoline. Therefore, controlling the water output can control the content of imidazoline. The higher the imidazoline content, the lower the viscosity and the slower the reaction speed. During underwater curing, the reaction speed also has a greater impact on the underwater bonding performance, and generally a fast reaction speed is helpful to improve the underwater bonding performance. Therefore, controlling the imidazoline content at a certain amount will achieve the best underwater curing bonding performance. It is not the case that the higher the content, the better.

[0028] In order to improve the underwater bonding performance, this requires that the curing agent has certain hydrophilicity and hydrophobicity, which is a contradiction in itself. The present invention is a novel amidoamine curing agent developed to solve this problem, and the curing agent controls the balance of hydrophilicity and hydrophobicity by controlling the content of imidazoline and phenolic resin. And in order to improve the bonding performance, the early stage is mainly based on hydrophilicity. When the epoxy resin system contacts the underwater interface, the imidazoline in the curing agent in the system first reacts with the water addition on the interface to generate modified aliphatic amine, which reacts with epoxy to generate a polymer, thereby better bonding the interface. The generated polymer is a copolymer of epoxy resin, phenolic resin and amine, and has a large cross-linking density, thereby having good water resistance and chemical resistance.

[0029] In the present invention, aliphatic amine and monoacid are used as the main agents to generate amidoamine, and then the generated amidoamine is further reacted and dehydrated to synthesize imidazoline. When solidified underwater, imidazoline first reacts with water on the bonding base surface to generate amidoamine, and then further reacts with epoxy resin to generate polymer. Since the water on the bonding base surface is reacted away, the adhesion of the epoxy resin system to the base surface is improved. This curing agent is mainly aliphatic amine, and polyetheramine can be added to improve the toughness problem, and meta-phenylenediamine is added to improve the low-temperature curing performance. In addition, due to the strong hydrophilicity of the amidoamine curing agent, the cured product will turn white, and the underwater bonding performance will be affected to a certain extent. Therefore, phenolic resin and phenolic compounds are introduced to modify the amidoamine curing agent to a certain extent, the hydrophobicity of the whole system is improved, and the hydrophobicity of the final cured product is also greatly improved, thereby extending the service life of the colloid soaked in long-term water.

[0030] Example 1

[0031] After 300g of tetraethylenepentamine and 150g of 2-methylpentanediamine are mixed evenly, 400g of oleic acid is added and reacted at 205℃ for 4 hours. A cooler is provided at the upper end of the reactor. During the reaction, the generated water vapor will condense into liquid water in the condenser and be discharged through the side port. It is dehydrated while reacting, and then cooled to 140℃. 110g of solid phenolic resin and 40g of bisphenol A resin are added, and then reacted for 3 hours. Cool the material to obtain a brown-yellow transparent liquid amidoamine curing agent. The amine value is 550mg KOH / g and the viscosity is 850 centipoise. The commonly used 128 liquid epoxy resin on the market is used with the curing agent in a ratio of 3:1 (weight ratio). It has good underwater bonding and mechanical properties. The pull-out strength after underwater curing is 3.5MPa, and there is no whitening on the surface of the cured product.

[0032] Example 2

[0033] After 350g of tetraethylenepentamine and 100g of D230 polyetheramine curing agent are mixed evenly, 390g of oleic acid is added and reacted at 210℃ for 4 hours. A cooler is provided at the upper end of the reactor. During the reaction, the generated water vapor will condense into liquid water in the condenser and be discharged through the side port. It is dehydrated while reacting, and then cooled to 140℃. 120g of solid phenolic resin and 30g of bisphenol A resin are added, and then reacted for 3 hours. Cool the material to obtain a brown-yellow transparent liquid amidoamine curing agent. The amine value is 510mg KOH / g and the viscosity is 1100 centipoise. The commonly used 128 liquid epoxy resin on the market is used with the curing agent in a ratio of 100:40 (weight ratio). It has good underwater bonding and mechanical properties. The pull-out strength after underwater curing is 3.6MPa, and there is no whitening on the surface of the cured product.

[0034] Example 3

[0035] After 350g of tetraethylenepentamine and 100g of m-phenylenediamine curing agent are mixed evenly, 420g of tall oil fatty acid is added and reacted at 210℃ for 4 hours. A cooler is provided at the upper end of the reactor. During the reaction, the generated water vapor will condense into liquid water in the condenser and be discharged through the side port. It is dehydrated while reacting, and then cooled to 140℃. 110g of solid phenolic resin and 30g of bisphenol A resin are added, and then reacted for 3 hours. Cool the material and obtain a brown-yellow transparent liquid amidoamine curing agent. The amine value is 580mg KOH / g and the viscosity is 750 centipoise. The commonly used 128 liquid epoxy resin on the market is used with the curing agent in a ratio of 3:1 (weight ratio). It has good underwater bonding and mechanical properties. The pull-out strength after underwater curing is 3.5MPa, and there is no whitening on the surface of the cured product.

[0036] Example 4

[0037] After 350g of tetraethylenepentamine, 100g of T403 polyetheramine and 100g of m-xylenediamine curing agent are mixed evenly, 460g of tall oil fatty acid is added and reacted at 210℃ for 4 hours. A cooler is provided at the upper end of the reactor. During the reaction, the generated water vapor will condense into liquid water in the condenser and be discharged through the side port. It is dehydrated while reacting, and then cooled to 140℃, 120g of solid phenolic resin and 30g of bisphenol A resin are added, and then reacted for 3 hours. Cool the material and obtain a brown-yellow transparent liquid amidoamine curing agent. The amine value is 560mg KOH / g and the viscosity is 700 centipoise. The commonly used 128 liquid epoxy resin on the market is used with the curing agent in a ratio of 100:35 (weight ratio). It has good underwater bonding and mechanical properties. The pull-out strength after underwater curing is 3.6MPa, and there is no whitening on the surface of the cured product.

[0038] Example 5

[0039] After 350g of tetraethylenepentamine, 50g of 2-methylpentanediamine and 100g of m-phenylenediamine curing agent are mixed evenly, 460g of tall oil fatty acid is added and reacted at 210℃ for 4 hours. A cooler is provided at the upper end of the reactor. During the reaction, the generated water vapor will condense into liquid water in the condenser and be discharged through the side port. It is dehydrated while reacting, and then cooled to 140℃, 120g of solid phenolic resin and 40g of bisphenol A resin are added, and then reacted for 3 hours. Cool the material to obtain a brown-yellow transparent liquid amidoamine curing agent. The amine value is 530mg KOH / g and the viscosity is 750 centipoise. The commonly used 128 liquid epoxy resin on the market is used with the curing agent in a ratio of 100:35 (weight ratio). It has good underwater bonding and mechanical properties. The pull-out strength after underwater curing is 3.6MPa, and there is no whitening on the surface of the cured product.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An amide-amine underwater curing agent for epoxy resin, characterized in that: The invention comprises the following components in parts by mass: 20 to 50 parts of amine, 20 to 50 parts of monoacid, 10 to 40 parts of phenolic compound and 5 to 20 parts of phenolic resin, wherein the amine is at least one of aliphatic amine, alicyclic amine and aromatic amine.

2. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The fatty amine is at least one of ethylenediamine, pentanediamine, hexamethylenediamine, 2-methylpentanediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

3. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The alicyclic amine may be at least one of HMDA, isophoronediamine and cyclohexanediamine.

4. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The aromatic amine is at least one of DDM, DETDA or m-xylylenediamine.

5. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The monoacid is at least one of oleic acid, tall oil fatty acid, and long-chain fatty monoacid.

6. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The phenolic compound is at least one of phenol, bisphenol A and cardanol.

7. The amidoamine underwater curing agent for epoxy resin according to claim 1, characterized in that: The phenolic resin is a polymer of phenol and formaldehyde.

8. A method for preparing the amidoamine underwater curing agent for epoxy resin according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Mix the amine and the monoacid evenly, raise the temperature to 190° C.-220° C., stir and react for at least 4 hours, and dehydrate during the reaction, and control the imidazoline content of the product to be 20%-70%; (2) The mixture of step (1) is cooled to 120-140° C., a phenolic compound and a phenolic resin are added, the reaction temperature is 120-150° C., and the reaction is performed for 3-5 hours to obtain a brown-yellow transparent liquid amidoamine curing agent.