A super-branched epoxy resin anticorrosive coating and a preparation method thereof

Abstract

The application belongs to the technical field of corrosion protection, and particularly relates to a hyperbranched epoxy resin anticorrosive coating and a preparation method thereof. The preparation method comprises the following steps: A2+B3 type hyperbranched epoxy resin is generated by reaction of bisphenol A and triglycidyl ether as raw materials; dopamine is introduced, and a dopamine modified hyperbranched epoxy resin is obtained through reaction of amino groups and end epoxy groups of the hyperbranched epoxy resin; a curing agent is added, and after uniform stirring, the mixture is coated on a metal surface, and after curing in an oven, a hyperbranched epoxy resin anticorrosive coating is obtained. The application fully gives the synergistic advantages of epoxy groups and polycyclic ring structures, the resin not only has the advantages of high hardness and high strength of epoxy resin, but also has the characteristics of good toughness and dense structure of hyperbranched polymers; the anticorrosive ability of the coating is greatly improved; the coating has high strength and hardness, and good salt water resistance and salt spray resistance.

Description

Technical fields:

[0001] This invention belongs to the field of anti-corrosion technology, specifically relating to a hyperbranched epoxy resin anti-corrosion coating and its preparation method. Background technology:

[0002] Metallic materials, with their unique superior properties and wide range of applications, have become the cornerstone of modern industry. However, metals inevitably suffer corrosion during use, especially in near-shore environments. It is estimated that my country suffers losses of trillions of yuan annually due to corrosion in fields such as ships, railways, bridges, and pipelines. Furthermore, metal corrosion poses significant safety hazards, causing immense disasters to human life and property and the natural environment. Therefore, accelerating the development of corrosion protection technologies to better control the corrosion of metallic materials in various environments is imperative and of great significance.

[0003] Common corrosion protection methods include electrochemical protection, the addition of corrosion inhibitors, and coating protection. Among these, coating protection is widely used due to its cost-effectiveness. Epoxy resins have a wide range of applications in metal corrosion protection due to their excellent mechanical properties, superior chemical resistance, and low shrinkage. However, the large molecular weight of epoxy resins requires the addition of large amounts of solvents during the coating process to adjust the viscosity of the system. This not only increases costs but also causes environmental harm due to the subsequent evaporation of solvents. Furthermore, the low elongation at break of epoxy resins makes the coating prone to brittleness. In recent years, researchers have achieved toughening by mixing epoxy resins with various readily soluble polymers, such as rubber and hyperbranched polyesters. However, sometimes the low compatibility leads to processing difficulties, such as the need for large amounts of solvents or high temperatures for processing rubber and epoxy resins. Therefore, developing epoxy resins with unique structures to optimize their inherent properties without relying on external additives is particularly important.

[0004] Hyperbranched polymers have attracted widespread attention in industrial-scale production and application due to their ease of synthesis, good solubility and low viscosity. Moreover, hyperbranched polymers contain abundant terminal groups, which can not only participate in crosslinking reactions, but also be used for post-modification without causing microphase separation and affecting coating performance.

[0005] Application number "202410195215.7" discloses a "hyperbranched epoxy resin coating and its preparation method," proposing a hyperbranched epoxy resin coating and its preparation method. While it solves the problems of traditional anti-icing coatings, such as the susceptibility of the anti-icing structure to damage and poor de-icing ability, it involves numerous raw materials, a complex preparation process, and the use of large amounts of organic solvents, failing to meet environmental protection requirements. Furthermore, the mechanical properties of the resulting coating are not mentioned; however, the core attribute of an anti-corrosion coating lies in its performance, especially its mechanical properties, because in actual use, the coating will inevitably be subjected to scratches and impacts, which will shorten its effective service life.

[0006] In summary, there is a need to develop a novel coating material that is simple to prepare, environmentally friendly, and possesses excellent mechanical properties, in order to more effectively protect the underlying metal. Summary of the Invention:

[0007] This invention provides a high-strength, high-hardness hyperbranched epoxy resin anti-corrosion coating and its preparation method, in order to solve the problems of existing technologies, such as the large number of raw materials, complex preparation process, and the use of large amounts of organic solvents, which do not meet environmental protection requirements.

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0009] A method for preparing a hyperbranched epoxy resin anti-corrosion coating includes the following steps:

[0010] Step 1: A2+B3 type hyperbranched epoxy resin is generated by reacting bisphenol A and triglycidyl ether as raw materials.

[0011] Step 2: Introduce dopamine and react the amino groups with the terminal epoxy groups of the hyperbranched epoxy resin to obtain dopamine-modified hyperbranched epoxy resin.

[0012] Step 3: Add curing agent, stir evenly, coat it onto the metal surface, and place it in an oven to cure, thus obtaining a hyperbranched epoxy resin anti-corrosion coating.

[0013] Furthermore, the above specifically includes the following steps, where the following quantities are parts by weight:

[0014] Step 1: Add bisphenol A and triglycidyl ether to a four-necked flask in sequence, then add the catalyst and stir the mixture at 80-100℃ for 12-24h to obtain a light yellow oily hyperbranched epoxy resin (HBPE).

[0015] Step 2: When the temperature drops to 40-60℃, add dopamine and stir for 1-3 hours under nitrogen protection to obtain end-modified light yellow oily hyperbranched epoxy resin (HBPE-DA).

[0016] Step 3: Mix the resin obtained in Step 3 with the curing agent, stir evenly, and then coat it onto the surface of the metal substrate. Cur it in an oven at 60-80℃ for 6-12 hours to obtain a hyperbranched epoxy resin anti-corrosion coating.

[0017] Furthermore, in step one above, bisphenol A is 5-10 parts by weight, triglycidyl ether is 20-80 parts by weight, and catalyst is 0.1-0.5 parts by weight.

[0018] Furthermore, in step two above, dopamine is present in an amount of 0.3-1 parts by mass.

[0019] Furthermore, in step three above, the mass ratio of resin to curing agent is 5-10 parts: 0.4-1.2 parts.

[0020] Furthermore, the catalyst mentioned in step one above is tetrabutylammonium bromide.

[0021] Furthermore, the curing agent mentioned in step three above is diethylenetriamine.

[0022] Furthermore, the hyperbranched epoxy resin anti-corrosion coating prepared by the above method.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. This invention uses bisphenol A and triglycidyl ether as raw materials. Unlike the previous multi-step synthesis method, this invention uses proton transfer polymerization to prepare hyperbranched epoxy resin in one step, which fully utilizes the synergistic advantages of epoxy groups and polybenzene ring structures. This resin not only has the advantages of high hardness and high strength of epoxy resin, but also has the characteristics of good toughness and dense structure of hyperbranched polymer.

[0025] 2. This invention uses dopamine to end-modify hyperbranched epoxy resin. Compared with the prior art, this invention mimics the adhesive protein molecules of mussels. The coating made with this resin is tightly bonded to the substrate under the action of the catechol structure, which greatly improves the anti-corrosion ability of the coating.

[0026] 3. The coating prepared by the present invention has high strength and hardness, as well as good resistance to salt water and salt spray, because the resin matrix is ​​composed of a hyperbranched structure of polybenzene rings and contains a mussel-like catechin structure. Attached Figure Description

[0027] Figure 1 Tensile curves of hyperbranched epoxy resin specimens;

[0028] Figure 2 This is a scanned image of the ductile fracture surface of a resin specimen.

[0029] Figure 3Salt spray test results of iron plate samples coated with resin:

[0030] (a) 1 day later (b) 7 days later (c) 15 days later (d) 30 days later. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention includes, but is not limited to, the scope shown in the following embodiments.

[0032] Example 1: A method for preparing a hyperbranched epoxy resin anti-corrosion coating, comprising the following steps:

[0033] Step 1: Add 5g of bisphenol A and 33.11g of triglycidyl ether to a four-necked flask, then add 0.25g of tetrabutylammonium bromide. Stir at 80℃ for 12h to obtain a light yellow oily hyperbranched epoxy resin (HBPE).

[0034] Step 2: After the temperature drops to 40℃, add 0.38g of dopamine and stir for 1 hour under nitrogen protection to obtain end-modified hyperbranched epoxy resin (HBPE-DA).

[0035] Step 3: Weigh 5g of modified hyperbranched epoxy resin, add 0.4g of diethylenetriamine, stir evenly, coat it on the surface of the iron plate, and place it in a 60℃ oven to cure for 6 hours to obtain a high-value epoxy resin anti-corrosion coating.

[0036] See Figure 1 As can be seen, the tensile strength of the sample prepared in Example 1 was 64.1 MPa, and the elongation at break was 14.8%.

[0037] See Figure 2 As can be seen, hyperbranched epoxy resin exhibits ductile fracture.

[0038] See Figure 3 As can be seen, no signs of corrosion were observed near the coating scratches after 30 days of salt spray testing.

[0039] The coating properties are shown in Table 1:

[0040] Table 1. Performance changes of the coating at different times after being placed in brine and salt spray chambers.

[0041]

[0042] Example 2: A method for preparing a hyperbranched epoxy resin anti-corrosion coating, comprising the following steps:

[0043] Step 1: Add 6g of bisphenol A and 39.73g of triglycidyl ether to a four-necked flask, then add 0.18g of tetrabutylammonium bromide. Stir at 90℃ for 18h to obtain a light yellow oily hyperbranched epoxy resin (HBPE).

[0044] Step 2: After the temperature drops to 50℃, add 0.92g of dopamine and stir for 2 hours under nitrogen protection to obtain end-modified hyperbranched epoxy resin (HBPE-DA).

[0045] Step 3: Weigh 6g of modified hyperbranched epoxy resin, add 0.6g of diethylenetriamine, stir evenly, coat it on the surface of the iron plate, and place it in a 70℃ oven to cure for 10h to obtain a high-value epoxy resin anti-corrosion coating.

[0046] The sample prepared in Example 2 had a tensile strength of 62.1 MPa and an elongation at break of 18.2%.

[0047] The coating properties are shown in Table 2:

[0048] Table 2 Performance changes of the coating at different times after being placed in salt water and salt spray chambers.

[0049]

[0050]

[0051] Example 3: A method for preparing a hyperbranched epoxy resin anti-corrosion coating, comprising the following steps:

[0052] Step 1: Add 5g of bisphenol A and 39.73g of triglycidyl ether to a four-necked flask, then add 0.2g of tetrabutylammonium bromide. Stir at 90℃ for 24h to obtain a light yellow oily hyperbranched epoxy resin (HBPE).

[0053] Step 2: After the temperature drops to 60℃, add 0.45g of dopamine and stir for 2 hours under nitrogen protection to obtain end-modified hyperbranched epoxy resin (HBPE-DA).

[0054] Step 3: Weigh 5g of modified hyperbranched epoxy resin, add 0.3g of diethylenetriamine, stir evenly, coat it on the surface of the iron plate, and place it in a 60℃ oven to cure for 8 hours to obtain a high-value epoxy resin anti-corrosion coating.

[0055] The sample prepared in Example 3 had a tensile strength of 59 MPa and an elongation at break of 14.7%.

[0056] The coating properties are shown in Table 3:

[0057] Table 3 Performance changes of the coating at different times after being placed in brine and salt spray chambers.

[0058]

[0059] Example 4: A method for preparing a hyperbranched epoxy resin anti-corrosion coating, comprising the following steps:

[0060] Step 1: Add 8g of bisphenol A and 63.5g of triglycidyl ether to a four-necked flask, then add 0.4g of tetrabutylammonium bromide. Stir at 80°C for 20 hours to obtain a light yellow oily hyperbranched epoxy resin (HBPE).

[0061] Step 2: After the temperature drops to 40℃, add 0.7g of dopamine and stir for 3h under nitrogen protection to obtain end-modified hyperbranched epoxy resin (HBPE-DA).

[0062] Step 3: Weigh 8g of modified hyperbranched epoxy resin, add 0.9g of diethylenetriamine, stir evenly, coat it on the surface of the iron plate, and place it in a 60℃ oven to cure for 6 hours to obtain a high-value epoxy resin anti-corrosion coating.

[0063] The sample prepared in Example 4 had a tensile strength of 57.3 MPa and an elongation at break of 12.9%.

[0064] The coating properties are shown in Table 4:

[0065] Table 4. Performance changes of the coating at different times after being placed in brine and salt spray chambers.

[0066]

[0067] The above embodiment 1 is the best embodiment.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a hyperbranched epoxy resin anti-corrosion coating, characterized in that: Includes the following steps: Step 1: A2+B3 type hyperbranched epoxy resin is generated by reacting bisphenol A and triglycidyl ether as raw materials. Step 2: Introduce dopamine and obtain dopamine-modified hyperbranched epoxy resin by reacting amino groups with the terminal epoxy groups of the hyperbranched epoxy resin. Step 3: Add curing agent, stir evenly, coat it on the metal surface, place it in an oven to cure, and obtain hyperbranched epoxy resin anti-corrosion coating. The specific steps include the following, where the following quantities are by weight: Step 1: Add bisphenol A and triglycidyl ether to a four-necked flask in sequence, then add a catalyst and stir the mixture at 80-100℃ for 12-24 hours to obtain a light yellow oily hyperbranched epoxy resin. Step 2: When the temperature drops to 40-60℃, add dopamine and stir for 1-3 hours under nitrogen protection to obtain end-modified light yellow oily hyperbranched epoxy resin. Step 3: Mix the resin obtained in Step 2 with the curing agent, stir evenly, and then coat it on the surface of the metal substrate. Cur it in an oven at 60-80℃ for 6-12 hours to obtain a hyperbranched epoxy resin anti-corrosion coating. In step one, bisphenol A is 5-10 parts by weight, triglycidyl ether is 20-80 parts by weight, and catalyst is 0.1-0.5 parts by weight. In step two, the amount of dopamine is 0.3-1 parts by mass; In step three, the mass ratio of resin to curing agent is 5-10 parts: 0.4-1.2 parts; The catalyst mentioned in step one is tetrabutylammonium bromide; The curing agent mentioned in step three is diethylenetriamine.

2. The hyperbranched epoxy resin anti-corrosion coating prepared by the method according to claim 1.

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