CN113444227B

CN113444227B - Underwater epoxy resin curing agent and preparation method thereof

Info

Publication number: CN113444227B
Application number: CN202110725362.7A
Authority: CN
Inventors: 裴须强; 朱玉雪; 宋作宝; 尹润平; 李婷; 力乙鹏; 张帅; 隗天骄
Original assignee: Cnbm Zhongyan Technology Co ltd
Current assignee: Cnbm Zhongyan Technology Co ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2022-03-25
Anticipated expiration: 2041-06-29
Also published as: CN113444227A

Abstract

The invention relates to an underwater epoxy resin curing agent, which consists of the following components: amine curing agent, bifunctional glycidyl ether, high brominated DGEBA, activity promoter, plasticizer and hydrophobic agent. The high-activity hydrogen atoms in the amine curing agent and epoxy groups in the bifunctional glycidyl ether and the high-brominated DGEBA are subjected to ring-opening reaction to form a new curing agent structure; meanwhile, based on the accelerator, the high reaction activity of the system is provided, the plasticizer improves the viscosity of the system and the mechanical property of a condensate, and the hydrophobic agent improves the underwater adhesion of the system, so that the problems of long underwater curing time, poor adhesion property and poor mechanical property of the current curing agent are effectively solved, and the weather resistance and environmental friendliness of the curing agent are improved.

Description

Underwater epoxy resin curing agent and preparation method thereof

Technical Field

The invention relates to the field of synthesis and preparation of high polymer materials, in particular to an underwater epoxy resin curing agent and a preparation method thereof.

Background

The epoxy resin material generally consists of resin and a curing agent, and has excellent adhesive property and outstanding mechanical property, so that the epoxy resin material is widely applied to structural repair and reinforcement engineering. At present, most of researches on epoxy resin concentrate on modification of a curing agent, but most of curing agents are still applied in a dry environment and are difficult to meet engineering application requirements of an underwater environment; concrete structures which are under water for a long time are easily damaged by erosion of water media and other factors, the working environment is severe, repair needs to be carried out in time after diseases are generated, and otherwise, the safe use and the durability of the whole structure are seriously influenced. In actual engineering, conditions of wet and underwater repair and reinforcement are frequently met, such as cracking of concrete members of channel aqueducts, cracking and surface layer falling of underwater concrete or reinforced concrete in dams of ports and wharfs, leakage of concrete aqueducts, outdoor repair and reinforcement in wet weather and rainy season, and the like, and the repair of the places in dry condition is very difficult.

With the development of technology, some underwater projects are gradually repaired, which is mainly attributed to the appearance of underwater curing agents. But the water is solidified in different air to react, the heat generated by the reaction is easy to dissipate, and the solidification time is prolonged; in addition, due to the existence of water molecules, the epoxy resin material is difficult to ensure good wettability to the interface, and the adhesive property is also reduced, so that the requirement on the underwater curing agent is higher. CN105542129A discloses a high-toughness hydrophobic epoxy curing agent and a preparation method thereof, the curing agent is prepared by taking aromatic amine, alkylphenol and aldehyde substances as monomer raw materials through Mannich reaction, and the three raw materials are in a molar ratio of (1.2-1.6): (1.0-1.4): 0.8 ingredient, and the preparation method comprises the following steps: mixing measured alkylphenol and aromatic amine, adding the mixture into a reaction flask, adding aldehyde substances in batches at 80 ℃, heating to 100 ℃ after dropwise adding, reacting for 4 hours, lapping a vacuumizing device, and performing reduced pressure distillation to remove water, wherein the formed curing agent has a ketimine structure and is poor in environmental friendliness; CN105331319A discloses an underwater curing epoxy resin adhesive, which comprises bisphenol A epoxy resin, polysulfide rubber, ketimine, modified amine, tris- (dimethylaminomethyl) phenol, xylene, n-butyl alcohol, a surfactant and a filler, wherein the prepared underwater epoxy resin adhesive still adopts a ketimine structure curing agent and has poor mechanical properties. Based on the patents, the problems that most of the existing underwater curing agents still adopt a ketimine structure, but the curing performance is poor, the environmental protection performance is poor and the like are obviously solved, and the large-scale application is difficult to meet.

Aiming at the problem, the invention forms a new curing agent structure by utilizing the ring-opening reaction of high-activity hydrogen atoms in an amine curing agent, bifunctional glycidyl ether and epoxy groups in high-brominated DGEBA; the introduction of Br atoms obviously improves the weather resistance of the curing agent structure, and the molecular weight of Br atoms can obviously reduce the volatility of the curing agent and improve the environmental protection property of Br atoms. Meanwhile, other auxiliary agents are introduced into the curing agent system, the accelerator provides high reaction activity for the system, the plasticizer improves the viscosity of the system and the mechanical property of a cured object, and the hydrophobic agent improves the underwater adhesion of the system, so that the epoxy resin curing agent with low viscosity, weather resistance and excellent underwater curing property is prepared, the problems of long underwater curing time, poor adhesion property and poor mechanical property of the existing curing agent are effectively solved, and the weather resistance and the environmental protection property of the curing agent are improved.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an underwater epoxy resin curing agent and a preparation method thereof. The epoxy resin curing agent with low viscosity, weather resistance and excellent curing performance in water can be prepared by modifying an amine curing agent by using bifunctional glycidyl ether and high brominated DGEBA and matching with an active accelerator, a plasticizer and a hydrophobing agent.

The preparation process has the advantages of easily available raw materials, simple method and simple and convenient operation, effectively solves the problems that the common epoxy resin curing agent is difficult to cure in water, the curing performance of the curing agent in water is poor, the environmental protection performance is poor and the like, and has very important significance for expanding the application of the underwater epoxy resin.

The underwater epoxy resin curing agent consists of the following parts: amine curing agent: 50-100 parts; difunctional glycidyl ethers: 10-40 parts; high brominated DGEBA: 5-30 parts; activity accelerator (b): 0-10 parts; plasticizer: 1-10 parts; a water repellent agent: 1-5 parts.

The amine curing agent is one or a combination of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine and m-xylylenediamine. The amine curing agent has high reactivity and can quickly react at room temperature, but the amine group causes the amine curing agent to have high volatility and certain toxicity, and the amine curing agent can be modified according to the actual application requirement, and is preferably one or a combination of ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine and m-xylylenediamine.

The difunctional glycidyl ether is low-molecular-weight difunctional epoxy, can be used as a diluent, can also react with an amine curing agent, and is preferably one or a combination of 1, 4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanediol diglycidyl ether and polyether glycol diglycidyl ether. In addition, the alkyl group in the glycidyl ether has a certain hydrophobic property, and can break a water film at an adhesive interface to improve adhesion to a substrate, and is more preferably one or a combination of 1, 4-butanediol diglycidyl ether, hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether.

The high-brominated DGEBA is prepared by reacting tetrabromobisphenol A with epichlorohydrin, brominated DGEBA with different molecular weights can be prepared by regulating the proportion of tetrabromobisphenol A to epichlorohydrin, the Br element prevents the corrosion of bacteria and potential harmful microorganisms, and the high-brominated DGEBA and a benzene ring act together to enhance the stability of a cured product (a product obtained by reacting a curing agent with resin) and the weather resistance in water, and preferably one or a combination of the high-brominated DGEBA with the relative molecular weight of 1000-4000. However, the viscosity of the brominated DGEBA increases with increasing molecular weight, and is preferably one or a combination of highly brominated DGEBA having a relative molecular weight of 1000 to 2000, and the molecular formula of the highly brominated DGEBA is shown below.

High brominated DGEBA molecular formula

The activity promoter can improve the reaction activity of the epoxy resin curing agent and shorten the gel curing time of the epoxy resin curing agent, and is preferably one or a combination of tertiary amine, methyldiethanolamine, phenol, dimethylaminomethylphenol and tris (dimethylaminomethyl) phenol (DMP 30). However, the tertiary amine, methyldiethanolamine and phenol have too high activity to facilitate the reaction control, and one or a combination of dimethylaminomethylphenol and tris (dimethylaminomethyl) phenol (DMP30) is more preferable.

The plasticizer can reduce the viscosity of a curing agent system, improve the impact strength of the curing agent after reaction with resin, increase the elongation at break of the material and provide the toughness of the material. In addition, the internal stress caused by curing shrinkage can be reduced, and the adhesive force of a cured product to a base material can be improved. Preferably one or a combination of dioctyl phthalate (DOP), dibutyl phthalate (DBP), dimethyl phthalate (DMP).

The hydrophobic agent is a hydrophobic substance, can prevent water molecules from entering the curing agent, and can remove water films during underwater bonding, so that the bonding force between the curing agent and a substrate is improved. Preferably one or a combination of methyl hydrogen silicone oil, petroleum ether, vegetable oil and solvent oil. However, methyl hydrogen silicone oil is more preferable in view of the environmental protection property of the curing agent system.

The preparation method comprises the following steps:

(1) mixing and stirring the weighed bifunctional glycidyl ether and the high brominated DGEBA at room temperature; then adding an amine curing agent, and stirring and reacting for 1-5h at 40-80 ℃;

(2) and cooling to room temperature, adding the weighed active accelerator, plasticizer and hydrophobing agent, and continuously stirring and uniformly mixing to obtain the underwater epoxy resin curing agent.

The beneficial results of the invention are:

the problems of long curing time in water, poor bonding performance and poor mechanical property of the curing agent are solved, and the weather resistance and the environmental protection performance of the curing agent are improved.

The total amine value of the prepared underwater epoxy resin curing agent is more than or equal to 500mgKOH/g, and the viscosity is less than or equal to 100 mPa.s; the curing reaction activity is high: the curing time of 100g of slurry underwater gel is less than or equal to 60 min; the condensate has good underwater performance (reacting with common epoxy resin): the 7d compressive strength is more than or equal to 80MPa, and the 7d elongation at break is more than or equal to 1%; the underwater bonding performance is good: the 7d bonding strength is more than or equal to 3.5 MPa; the weather resistance is good: the retention rate of 28d compressive strength under the dual action of water and ultraviolet rays is more than or equal to 90 percent; the environmental protection property is good: has oral toxicity LD50 more than 40mg/g, and has no volatile solvent such as acetone and benzene. In addition, the curing agent system has common raw materials in the preparation process and simple preparation process; and when the flame retardant is used under the condition of a dry environment, the Br element also has good flame retardant property.

Detailed Description

The present invention will be further described with reference to the following examples.

The raw materials used in the examples are commercially available, and the experimental procedures are conventional test procedures unless otherwise specified.

Example 1

Diethylene triamine, neopentyl glycol diglycidyl ether, high brominated DGEBA having a relative molecular weight of 1400, tris (dimethylaminomethyl) phenol, dibutyl phthalate, methyl hydrogen silicone oil were weighed in a mass ratio of 60:15:15:5:3: 2. Mixing and stirring neopentyl glycol diglycidyl ether and high brominated DGEBA with the relative molecular weight of 1400, adding a diethylenetriamine curing agent, and stirring and reacting for 3 hours at the temperature of 50 ℃; cooling to room temperature, adding weighed tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 2

Triethylenetetramine, hexanediol diglycidyl ether, highly brominated DGEBA having a relative molecular weight of 1400, highly brominated DGEBA having a relative molecular weight of 2000, tris (dimethylaminomethyl) phenol, dioctyl phthalate and methyl hydrogen silicone oil were weighed in a mass ratio of 60:20:5:5:6:2: 2. Firstly, mixing and stirring hexanediol diglycidyl ether and high brominated DGEBA with the relative molecular weight of 1400, then adding a triethylenetetramine curing agent, and stirring and reacting for 2 hours at the temperature of 65 ℃; cooling to room temperature, adding weighed tris (dimethylamino methyl) phenol, dioctyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 3

Triethylene tetramine, hexanediol diglycidyl ether, high brominated DGEBA with the relative molecular weight of 1600, dimethylamino methylphenol, dioctyl phthalate and methyl hydrogen silicone oil are weighed according to the mass ratio of 70:30:10:5:2: 3. Firstly, mixing and stirring hexanediol diglycidyl ether and high brominated DGEBA with the relative molecular weight of 1600, then adding a triethylene tetramine curing agent, and stirring and reacting for 4 hours at the temperature of 45 ℃; cooling to room temperature, adding weighed dimethylamino methyl phenol, dioctyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 4

Ethylenediamine, 1, 4-butanediol diglycidyl ether, high brominated DGEBA with the relative molecular weight of 2000, dimethylamino methylphenol, dibutyl phthalate and methyl hydrogen silicone oil are weighed according to the mass ratio of 55:20:15:1:6: 3. Firstly, 1, 4-butanediol diglycidyl ether and high brominated DGEBA with the relative molecular weight of 2000 are mixed and stirred, then an ethylenediamine curing agent is added, and the mixture is stirred and reacts for 1.5 hours at the temperature of 70 ℃; and cooling to room temperature, adding weighed dimethylamino methyl phenol, dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 5

Diethylene triamine, neopentyl glycol diglycidyl ether, ordinary DGEBA having a relative molecular weight of 1000, tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen silicone oil were weighed in a mass ratio of 60:15:15:5:3: 2. Mixing neopentyl glycol diglycidyl ether and common DGEBA with the relative molecular weight of 1000, stirring, adding a diethylenetriamine curing agent, and reacting for 2 hours at 50 ℃; cooling to room temperature, adding weighed tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 6

Diethylene triamine, neopentyl glycol diglycidyl ether, high brominated DGEBA having a relative molecular weight of 1400, dibutyl phthalate and methyl hydrogen silicone oil were weighed in a mass ratio of 60:15:15:7: 3. Mixing and stirring neopentyl glycol diglycidyl ether and high brominated DGEBA with the relative molecular weight of 1400, adding a diethylenetriamine curing agent, and reacting for 1.5h at the temperature of 60 ℃; and cooling to room temperature, adding the weighed dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 7

Diethylene triamine, neopentyl glycol diglycidyl ether, tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen silicone oil are weighed according to the mass ratio of 70:20:5:3: 2. Firstly, adding neopentyl glycol diglycidyl ether into a diethylenetriamine curing agent, and stirring and reacting for 3 hours at the temperature of 50 ℃; cooling to room temperature, adding weighed tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

Example 8

Diethylene triamine, high brominated DGEBA having a relative molecular weight of 1400, tris (dimethylaminomethyl) phenol, dibutyl phthalate, methyl hydrogen silicone oil were weighed in a mass ratio of 70:20:5:3: 2. Firstly, high-brominated DGEBA with the relative molecular weight of 1400 is mixed and stirred and added into a diethylenetriamine curing agent, and stirring reaction is carried out for 2 hours at the temperature of 60 ℃; cooling to room temperature, adding weighed tris (dimethylaminomethyl) phenol, dibutyl phthalate and methyl hydrogen-containing silicone oil, and continuously mixing and stirring.

The curing agents obtained in the above examples 1, 2, 3, 4, 5, 6, 7 and 8 were subjected to amine number test and viscosity test, specifically as follows:

categories	Total amine value/mgKOH.g^-1	viscosity/mPa.s
			Example 1	540	45
Example 2	650	57
			Example 3	620	51
Example 4	500	72
			Example 5	491	126
Example 6	470	119
			Example 7	530	43
Example 8	565	87

The curing performance test of the epoxy resin is carried out by uniformly mixing the above examples 1, 2, 3, 4, 5, 6, 7, 8 and the ordinary curing agent with the ordinary epoxy resin E51 respectively (according to the mass ratio of 1:3), and specifically comprises the following steps:

compared with the common curing agent for the underwater epoxy resin, the curing agent system disclosed by the invention has the advantages of better curing performance, shorter curing time of underwater gel, better mechanical property after reaction with resin and higher underwater bonding strength than the common curing agent. In addition, the cured product formed after the reaction with the resin also has better weather resistance, and the 28d compressive strength retention rate under the double action of water and ultraviolet rays is more than or equal to 90 percent and is far superior to the cured product formed by a common curing agent system; the environmental protection is obviously improved, the oral toxicity (mouse) LD50 is more than 40mg/g, the curing agent is much higher than the common underwater curing agent, and the curing agent does not contain volatile solvents such as acetone, benzene and the like.

The comparison of examples 1 to 4 shows that the selection of different amine curing agents has a certain influence on the mechanical properties of the cured product formed by the reaction of the final underwater curing agent and the epoxy resin, and the larger the amine value of the final underwater curing agent is, the larger the activity of the curing agent is, and the shorter the gel time of the reaction with the resin is. In addition, the mixing amount of the high-activity accelerator also has great influence on the reaction activity of the curing agent, for example, the mixing amount of the accelerator is reduced in example 4, and the gel time of the reaction with the resin is obviously prolonged under the same mixing ratio.

Comparison of examples 1 to 4 with example 5 shows that the mechanical properties of the cured product are reduced when ordinary DGEBA is used instead of highly brominated DGEBA.

Comparing examples 1-4 with example 6, it can be seen that the gel curing reaction of the system is significantly increased and the adhesive strength is reduced when the active promoter is removed and the system reacts with the resin.

Comparison of examples 1 to 4 with example 7 shows that, when the highly brominated DGEBA is removed, the curing agent has improved viscosity, but the cured product has significantly reduced weather resistance, compressive strength, adhesive properties, and the like.

Comparing examples 1 to 4 with example 8, it was found that when bifunctional glycidyl ether was removed, the viscosity of the curing agent was increased, the adhesive property was decreased, and the environmental protection property was deteriorated.

In conclusion, it can be found that the presence of the highly active accelerator can accelerate the reaction rate of the resin and the curing agent, shorten the time of gel curing reaction, and simultaneously reduce the viscosity of the curing agent system. The chain alkyl and the hydrophobic agent in the glycidyl ether can destroy a water film of an adhesive interface, improve the adhesive force with a matrix and improve the underwater adhesive strength of the curing agent, so that the curing agent prepared by the method has better underwater adhesive property than the common curing agent. In addition, the existence of the high-brominated DGEBA also improves the weather resistance and stability of a curing agent system and enhances the mechanical property of a cured material.

Claims

1. The underwater epoxy resin curing agent is characterized by comprising the following components: amine curing agent: 50-100 parts; difunctional glycidyl ethers: 10-40 parts; high brominated DGEBA: 5-30 parts; 0 part of the activity promoter is more than or equal to 10 parts; plasticizer: 1-10 parts; a water repellent agent: 1-5 parts of high-brominated DGEBA, wherein the high-brominated DGEBA is one or a combination of high-brominated DGEBAs with the relative molecular weight of 1000-4000.

2. The underwater epoxy resin curing agent of claim 1, wherein the amine curing agent is one or a combination of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, and m-xylylenediamine.

3. The underwater epoxy resin curing agent of claim 1, wherein the difunctional glycidyl ether is one or a combination of 1, 4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanediol diglycidyl ether, and polyether glycol diglycidyl ether.

4. The underwater epoxy resin curing agent of claim 1, wherein the activity promoter is one or a combination of triethylamine, triethanolamine, benzyldimethylamine, dimethylaminomethylphenol, tris (dimethylaminomethyl) phenol.

5. The curing agent for underwater epoxy resins of claim 1 wherein the plasticizer is one or a combination of dioctyl phthalate, dibutyl phthalate, and dimethyl phthalate.

6. The underwater epoxy resin curing agent of claim 1, wherein the hydrophobic agent is one or a combination of methyl hydrogen silicone oil, petroleum ether, vegetable oil and solvent oil.

7. The process for preparing an underwater epoxy resin curing agent according to any one of claims 1 to 6, comprising the steps of:

(1) mixing and stirring the weighed bifunctional glycidyl ether and the high brominated DGEBA at room temperature; then adding excessive amine curing agent, stirring and reacting for 1-5h at 40-80 ℃ to obtain prepolymer;