Low-temperature curing agent for epoxy coating and preparation process of low-temperature curing agent

Abstract

The invention relates to the field of curing agent materials, in particular to a low-temperature curing agent for an epoxy coating and a preparation process of the low-temperature curing agent. The low-temperature curing agent comprises aliphatic polyamine, organic acid salt, nano silicon dioxide, an environment-friendly additive, an antioxidant, an ultraviolet light absorber and a rheology modifier, the invention relates to an environment-friendly adhesive which comprises the following components in percentage by mass: 60-80% of aliphatic polyamine, 10-30% of organic acid salt, 5-20% of nano silicon dioxide, 0.5-5% of an environment-friendly additive, 0.1-3% of an antioxidant, 0.05-2% of an ultraviolet light absorber and 1-10% of a rheology modifier. According to the low-temperature curing agent, the curing efficiency of the epoxy coating can be remarkably improved, the curing time is shortened, the production efficiency is improved, the low-temperature curing agent enables the epoxy coating to be applied to wider environmental conditions including low-temperature and high-humidity environments, the mechanical property, the wear resistance, the chemical resistance and the corrosion resistance of the epoxy coating can be improved, and the service life of the epoxy coating is prolonged. The requirements of high-performance application are met, an environment-friendly low-temperature curing agent is developed, the use of harmful chemical substances is reduced, and the current environment-friendly trend is met.

Description

Technical Field

[0001] The present invention relates to the field of curing agent materials, and more particularly to a low-temperature curing agent for epoxy coatings and its preparation process. Background Art

[0002] The low-temperature curing agent for epoxy coatings is an important branch in the field of epoxy resin coatings. With the development of technology, the market demand for curing agents that can effectively cure at lower temperatures is increasing day by day, especially in industries such as construction, transportation, and composite materials. The research and development of low-temperature curing agents aims to provide a curing agent that can cure quickly at lower temperatures while maintaining excellent performance.

[0003] Traditional epoxy coating curing agents usually require relatively high curing temperatures, which limits their application in low-temperature environments, restricts their scope of use, and at the same time, the curing efficiency of the curing agent is low, and its own corrosion resistance is poor, unable to meet the use in relatively harsh environments, reducing its own service life.

[0004] Therefore, we make improvements and propose a low-temperature curing agent for epoxy coatings and its preparation process. Summary of the Invention

[0005] The purpose of the present invention is to address the problems that currently existing traditional epoxy coating curing agents usually require relatively high curing temperatures, which limits their application in low-temperature environments, restricts their scope of use, and at the same time, the curing efficiency of the curing agent is low, and its own corrosion resistance is poor, unable to meet the use in relatively harsh environments.

[0006] To achieve the above-mentioned invention purpose, the present invention provides a low-temperature curing agent for epoxy coatings and its preparation process to improve the above problems.

[0007] Specifically, this application is as follows:

[0008] A low-temperature curing agent for epoxy coatings, comprising: aliphatic polyamine, organic acid salt, nano-silica, environmental protection additive, antioxidant, ultraviolet absorber, and rheological modifier.

[0009] As a preferred technical solution of this application, the mass ratio of each component includes: aliphatic polyamine 60 - 80%, organic acid salt 10 - 30%, nano-silica 5 - 20%, environmental protection additive 0.5 - 5%, antioxidant 0.1 - 3%, ultraviolet absorber 0.05 - 2%, and rheological modifier 1 - 10%.

[0010] As a preferred technical solution of this application, it further includes a mildew-proof agent 0.01 - 1%.

[0011] As a preferred technical solution of this application, it further includes an antistatic agent 0.05 - 3%.

[0012] As a preferred technical solution of the present application, the organic acid salt is one of citrate and tartrate.

[0013] As a preferred technical solution of the present application, the average particle size of the nano-silica is less than 100 nanometers.

[0014] A preparation process of a low-temperature curing agent for an epoxy coating comprises the following steps:

[0015] S1. Organic acid salt treatment: Select citrate as the organic acid salt component and carry out dissolution treatment;

[0016] S2. Nano-silica dispersion: Disperse the nano-silica in a medium to ensure that the average particle size is less than 100 nanometers;

[0017] S3. Environment-friendly additive mixing: Mix the plant extract environment-friendly additive with other components, and mix all the components evenly in a stirrer until a uniform mixture is formed;

[0018] S4. Temperature control: Control the reaction temperature during the whole preparation process to ensure the effective reaction of each component and the stability of the mixture.

[0019] As a preferred technical solution of the present application, a temperature sensor is installed on the stirrer.

[0020] As a preferred technical solution of the present application, a spiral heating ring is installed on the surface of the stirrer. The spiral heating ring is wound around the surface of the stirrer for uniformly heating the stirrer, controlling the temperature of the mixture in the inner cavity of the stirrer, detecting the pH value of the mixture during the mixing process, and a pH regulator controls the pH value of the mixture between 7.0 and 8.5.

[0021] As a preferred technical solution of the present application, it further comprises a defoaming treatment step:

[0022] A: Prepare the curing agent mixture: After completing the mixing and stirring step, transfer the obtained curing agent mixture to a container for defoaming treatment;

[0023] B: Set the vacuum environment: Place the container of the curing agent mixture in a vacuum defoaming machine, adjust the vacuum degree of the vacuum defoaming machine, and the pressure < 0.1 MPa.

[0024] C: Heating: Heat the mixture to improve the defoaming efficiency, and set the heating temperature to 40 - 60 °C;

[0025] D: Start the defoaming program: Start the vacuum defoaming machine to make the curing agent mixture defoam in a vacuum environment, and observe and record the vacuum degree and temperature;

[0026] E: Maintaining the defoaming time: The defoaming time is 10 - 30 min. During defoaming, observe the escape of bubbles in the curing agent through video monitoring;

[0027] F: Ending the defoaming treatment: After completing defoaming, release the pressure in the vacuum environment to avoid the re - formation of bubbles in the curing agent due to too rapid pressure change, and take out the curing agent mixture from the vacuum defoaming machine.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] In the solution of the present application:

[0030] 1. In order to solve the problems in the prior art that traditional epoxy coating curing agents usually require relatively high curing temperatures, which limit their application in low - temperature environments, the scope of use is restricted. At the same time, the curing efficiency of the curing agent is low, and its own corrosion resistance is poor, making it unable to meet the requirements for use in relatively harsh environments. The low - temperature curing agent in the present application can significantly improve the curing efficiency of epoxy coatings, shorten the curing time, and improve production efficiency. The low - temperature curing agent enables epoxy coatings to be applied under a wider range of environmental conditions, including low - temperature and high - humidity environments;

[0031] 2. The low - temperature curing agent in the present application can enhance the mechanical properties, wear resistance, chemical resistance, and corrosion resistance of epoxy coatings, meet the requirements of high - performance applications, develop environmentally friendly low - temperature curing agents, reduce the use of harmful chemical substances, and conform to the current environmental protection trend.

[0032] 3. The epoxy coating using the low - temperature curing agent in the present application has a relatively fast drying speed and a long pot life. It can be constructed in summer without phenomena such as explosive polymerization, and also has a relatively fast drying speed at lower temperatures. Therefore, it has a wide range of applications and good chemical corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a principle flow chart of the preparation process of the low - temperature curing agent for epoxy coatings provided by the present application;

[0034] Figure 2 It is a defoaming treatment flow chart of the preparation process of the low - temperature curing agent for epoxy coatings provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] As described in the background art, traditional epoxy coating curing agents usually require relatively high curing temperatures, which limits their application in low-temperature environments, restricts their scope of use, and at the same time, the curing efficiency of the curing agent is low, and its own corrosion resistance is poor, unable to meet the use requirements in relatively harsh environments.

[0037] To solve this technical problem, the present invention provides a low-temperature curing agent for epoxy coatings, comprising: aliphatic polyamine, organic acid salt, nano-silica, environmental protection auxiliary agent, antioxidant, ultraviolet absorber and rheological modifier.

[0038] The mass ratio of each component includes: 60-80% of aliphatic polyamine, 10-30% of organic acid salt, 5-20% of nano-silica, 0.5-5% of environmental protection auxiliary agent, 0.1-3% of antioxidant, 0.05-2% of ultraviolet absorber and 1-10% of rheological modifier.

[0039] It also includes 0.01-1% of mildew preventive, which is used to prevent microbial contamination of the curing agent during storage and use.

[0040] It also includes 0.05-3% of antistatic agent, which is used to reduce the static electricity accumulation of the curing agent during processing and use.

[0041] The organic acid salt is one of citrate and tartrate.

[0042] The average particle size of the nano-silica is less than 100 nanometers, and the environmental protection auxiliary agent includes plant extracts.

[0043] The low-temperature curing agent of the present application can significantly improve the curing efficiency of the epoxy coating, shorten the curing time, improve the production efficiency, and enable the epoxy coating to be applied under a wider range of environmental conditions, including low-temperature and high-humidity environments.

[0044] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0045] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments can be combined with each other.

[0046] Example 1, a low-temperature curing agent for epoxy coatings, comprising: aliphatic polyamine, organic acid salt, nano-silica, environmental protection auxiliary agent, antioxidant, ultraviolet absorber and rheological modifier.

[0047] The mass ratio of each component includes: 70% of aliphatic polyamine, 20% of organic acid salt, 15% of nano-silica, 3% of environmental protection auxiliary agent, 2% of antioxidant, 1% of ultraviolet absorber and 5% of rheological modifier.

[0048] It also includes 0.5% of a mildew-proof agent, which is used to prevent microbial contamination of the curing agent during storage and use.

[0049] It also includes 1.5% of an antistatic agent, which is used to reduce the static electricity accumulation of the curing agent during processing and use.

[0050] The organic acid salt is one of citrate and tartrate.

[0051] The average particle size of the nano-silica is less than 100 nanometers, and the environmental protection auxiliary agent includes plant extracts.

[0052] Example 2, a low-temperature curing agent for epoxy coatings, includes: aliphatic polyamine, organic acid salt, nano-silica, environmental protection auxiliary agent, antioxidant, ultraviolet absorber, and rheological modifier.

[0053] The mass ratio of each component includes: 80% of aliphatic polyamine, 30% of organic acid salt, 20% of nano-silica, 5% of environmental protection auxiliary agent, 3% of antioxidant, 2% of ultraviolet absorber, and 10% of rheological modifier.

[0054] It also includes 1% of a mildew-proof agent, which is used to prevent microbial contamination of the curing agent during storage and use.

[0055] It also includes 3% of an antistatic agent, which is used to reduce the static electricity accumulation of the curing agent during processing and use.

[0056] The organic acid salt is one of citrate and tartrate.

[0057] The average particle size of the nano-silica is less than 100 nanometers, and the environmental protection auxiliary agent includes plant extracts.

[0058] Example 3, a low-temperature curing agent for epoxy coatings, includes: aliphatic polyamine, organic acid salt, nano-silica, environmental protection auxiliary agent, antioxidant, ultraviolet absorber, and rheological modifier.

[0059] The mass ratio of each component includes: 60% of aliphatic polyamine, 10% of organic acid salt, 5% of nano-silica, 0.5% of environmental protection auxiliary agent, 0.1% of antioxidant, 0.05% of ultraviolet absorber, and 1% of rheological modifier.

[0060] It also includes 0.01% of a mildew-proof agent, which is used to prevent microbial contamination of the curing agent during storage and use.

[0061] It also includes 0.05% of an antistatic agent, which is used to reduce the static electricity accumulation of the curing agent during processing and use.

[0062] The organic acid salt is one of citrate and tartrate.

[0063] The average particle size of nano-silica is less than 100 nanometers, and the environmental protection additive includes plant extracts.

[0064] Example 4, as Figure 1 and Figure 2 , A preparation process of a low-temperature curing agent for an epoxy coating, comprising the following steps:

[0065] S1. Organic acid salt treatment: Select citrate as the organic acid salt component and perform dissolution treatment;

[0066] S2. Nano-silica dispersion: Disperse nano-silica in a medium to ensure that the average particle size is less than 100 nanometers;

[0067] S3. Environmental protection additive mixing: Mix the plant extract environmental protection additive with other components, and mix all components evenly in a stirrer until a uniform mixture is formed;

[0068] S4. Temperature control: Control the reaction temperature throughout the preparation process to ensure the effective reaction of each component and the stability of the mixture.

[0069] Install a temperature sensor on the stirrer to monitor the temperature of the mixture inside the stirrer in real time and feedback it to the electric control box, and the electric control box displays the temperature parameters through the display screen on the surface.

[0070] Install a spiral heating ring on the surface of the stirrer. The spiral heating ring is wound around the surface of the stirrer to uniformly heat the stirrer, control the temperature of the mixture in the inner cavity of the stirrer, and detect the pH value of the mixture during the mixing process. The pH regulator controls the pH value of the mixture between 8.

[0071] It also includes a defoaming treatment step:

[0072] A: Prepare the curing agent mixture: After completing the mixing and stirring step, transfer the obtained curing agent mixture to a container for defoaming treatment;

[0073] B: Set the vacuum environment: Place the container of the curing agent mixture in a vacuum defoaming machine, adjust the vacuum degree of the vacuum defoaming machine, and the pressure is 0.08 MPa.

[0074] C: Heating: Heat the mixture to improve the defoaming efficiency, and set the heating temperature to 50 °C;

[0075] D: Start the defoaming program: Start the vacuum defoaming machine to defoam the curing agent mixture in a vacuum environment, and observe and record the vacuum degree and temperature;

[0076] E: Maintain the defoaming time: The defoaming time is 20 min. During the defoaming process, observe the escape of bubbles in the curing agent through video monitoring;

[0077] F: End of degassing treatment: After degassing is completed, release the pressure in the vacuum environment to avoid the re-formation of bubbles in the curing agent due to too rapid pressure change, and take out the curing agent mixture from the vacuum degassing machine.

[0078] Example 5, A low-temperature curing agent for epoxy coatings, the nano-silica dispersion treatment includes the following steps:

[0079] a. Predispersion: Gradually add nano-silica powder into the dispersion medium, and at the same time turn on the stirrer for preliminary stirring to break the agglomeration state of the nano-silica powder; the stirring speed is controlled at 1500 revolutions per minute, and the stirring time is 60 minutes;

[0080] b. Ultrasonic dispersion: Place the preliminarily dispersed nano-silica suspension in an ultrasonic disperser. The shock waves and microjets generated by the cavitation effect of the ultrasonic waves can crush the agglomerates of nano-silica and make it more evenly dispersed in the medium. The ultrasonic power is 1000 watts, the frequency is 40 kHz, and the ultrasonic dispersion time is 60 minutes;

[0081] c. High-speed shear dispersion: Transfer the suspension after ultrasonic dispersion to a high-speed shear disperser, turn on the high-speed shear disperser, and perform high-speed shear treatment on the suspension. High-speed shear can further break the agglomerates of nano-silica and make its particle size more uniform. The time of high-speed shear dispersion is 120 minutes;

[0082] d. Particle size detection: Use a particle size analyzer to detect the particle size of the dispersed nano-silica suspension. The detection results need to be compared with the process requirements to ensure that the average particle size is less than 100 nm. If the detection results do not meet the requirements, adjust the dispersion conditions according to the detection results, and then perform the dispersion treatment until the detection results meet the requirements.

[0083] Organic acid salts and nano-silica can accelerate the curing reaction and reduce the curing temperature, thereby shortening the curing time. The addition of a rheological modifier can improve the rheology of the coating, making it have better flexibility and crack resistance. At the same time, the good dispersion of nano-silica can also improve the toughness of the coating. The comparison between the obtained curing agent and the existing low-temperature curing agent is as shown in the following table:

[0084] Dimension Obtained curing agent Existing low-temperature curing agent Curing time 4 hours (room temperature) 8 hours (room temperature) Strength (MPa) 50 35 Toughness (elongation at break %) 15％ 10％

[0085] Obviously, the embodiments described above are only a part of the embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are shown in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structure made by using the content of the specification and drawings of the present invention, directly or indirectly applied to other related technical fields, is similarly within the scope of the patent protection of the present invention.

Claims

1. A low temperature curing agent for epoxy coating, characterized in that: include: Aliphatic polyamines, organic acid salts, nano-silica, environmental additives, antioxidants, UV absorbers and rheology modifiers.

2. A low temperature curing agent for epoxy coating according to claim 1, characterized in that: The mass proportions of the components include: 60-80% of aliphatic polyamine, 10-30% of organic acid salt, 5-20% of nano silicon dioxide, 0.5-5% of environmental protection additive, 0.1-3% of antioxidant, 0.05-2% of ultraviolet absorber and 1-10% of rheology modifier.

3. A low temperature curing agent for epoxy coating according to claim 2, characterized in that: Also includes mildew preventer 0.01-1%.

4. A low temperature curing agent for epoxy coating according to claim 3, characterized in that: Also includes antistatic agent 0.05-3%.

5. A low temperature curing agent for epoxy coating according to claim 4, characterized in that: The organic acid salt is one of citrate and tartrate.

6. A low temperature curing agent for epoxy coating according to claim 5, characterized in that: The average particle size of nano-silicon dioxide is less than 100 nanometers.

7. A process for preparing a low-temperature curing agent for epoxy coatings, using the low-temperature curing agent for epoxy coatings as claimed in claim 6, characterized in that: The following steps are involved: S1. Organic acid salt treatment: citrate is selected as the organic acid salt component and is dissolved; S2. Nano-silicon dioxide dispersion: Disperse nano-silicon dioxide in the medium to ensure that the average particle size is less than 100 nanometers; S3, environmental protection auxiliary agent mixing: mixing the plant extract environmental protection auxiliary agent with other components, and mixing all the components in a blender until a uniform mixture is formed; S4. Temperature control: Control the reaction temperature during the entire preparation process to ensure the effective reaction of each component and the stability of the mixture.

8. The process for preparing a low-temperature curing agent for epoxy coating according to claim 7, characterized in that: Install a temperature sensor on the stirrer.

9. The process for preparing a low-temperature curing agent for epoxy coating according to claim 8, characterized in that: A spiral heating ring is installed on the surface of the agitator. The spiral heating ring is wound around the surface of the agitator and is used to evenly heat the agitator, control the temperature of the mixture in the inner cavity of the agitator, detect the pH value of the mixture during the mixing process, and the pH adjuster controls the pH value of the mixture between 7.0-8.

5.

10. The process for preparing a low-temperature curing agent for epoxy coating according to claim 9, characterized in that: It also includes a degassing step: A: Prepare the curing agent mixture: After completing the mixing and stirring step, transfer the obtained curing agent mixture to a degassing container; B: Set up a vacuum environment: Place the container of the curing agent mixture in a vacuum degassing machine and adjust the vacuum degree of the vacuum degassing machine to a pressure of <0.1MPa. C: Heating: Heat the mixture to improve degassing efficiency, and set the heating temperature to 40-60°C; D: Start the degassing procedure: Start the vacuum degassing machine to degas the curing agent mixture in a vacuum environment, and observe and record the vacuum degree and temperature; E: Degassing time: The degassing time is 10-30 minutes. During the degassing process, the escape of bubbles in the curing agent is observed through video monitoring; F: End of degassing: After degassing is completed, release the pressure in the vacuum environment to avoid the re-formation of bubbles in the curing agent due to rapid pressure changes, and take the curing agent mixture out of the vacuum degassing machine.

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