A bio-based epoxy resin coating for marine engineering and its preparation method

Abstract

This invention proposes a bio-based epoxy resin coating for marine engineering and its preparation method, relating to the technical field of marine engineering anti-corrosion coatings. The coating is composed of two components, A and B. Component A, by weight, includes: 30-32 parts of a bio-based epoxy resin, 6-8 parts of a reactive diluent, 0.2-0.4 parts of a defoamer, 0.2-0.4 parts of a dispersant, 1.6-1.8 parts of an anti-settling agent, 44-48 parts of a filler, 4-6 parts of zinc phosphate, and 7-9 parts of aluminum tripolyphosphate; and component B includes: 0.4-0.6 parts of a drier and 25-28 parts of a curing agent. The bio-based epoxy resin is a magnolol-based epoxy resin with a molecular weight of 2400-6500. Magnolol-based epoxy resin takes advantage of the characteristics of the molecular structure of magnolia phenol and introduces a more flexible acrylic-based structure to adjust the flexibility and viscosity of the resin molecules. Adding it to the coating makes it easy to apply and can cure quickly, meeting the construction environment of the marine environment. The paint film formed has high strength and good flexibility and can withstand long-term wave erosion.

Description

Technical Field

[0001] The present invention relates to the technical field of marine engineering anti-corrosion coatings, and in particular to a bio-based epoxy resin coating for marine engineering and a preparation method thereof. Background Art

[0002] The marine environment presents harsh corrosion conditions. The salt and humidity in the seawater can cause corrosion in metal structures, accelerating their aging and damage, reducing their strength and stability. Furthermore, the waste and chemicals produced by metal corrosion pollute the marine ecosystem, hindering its health. Anti-corrosion coatings can form a protective film on the surface of metal structures, isolating them from direct contact with seawater, thereby preventing corrosion, extending their lifespan, reducing maintenance costs, protecting the environment, and improving the safety and reliability of engineering facilities.

[0003] Epoxy resin refers to an oligomer containing two or more epoxy groups, with organic compounds such as aliphatic, alicyclic or aromatic groups as a skeleton and capable of forming useful thermosetting products through epoxy group reaction. As a film-forming substance for anti-corrosion coatings, epoxy resin has good adhesion, corrosion resistance, wear resistance and chemical resistance, can effectively protect metal structures, extend its service life, and is one of anti-corrosion coating components commonly used in marine engineering. The Chinese patent literature with application publication number CN117025050A provides a kind of magnolia phenol-based epoxy resin anti-corrosion coating and preparation method thereof. The coating uses bio-based epoxy resin as the main film-forming substance, has higher environmental performance, and can well adapt to high humidity and high salt spray environment at sea. However, the environment of marine engineering is special, requiring resin to meet rapid curing under low temperature conditions and to withstand water scouring. In the coating curing process in the above scheme, the initial reaction speed is fast, but the terminal reaction speed is slower, i.e., the surface drying speed is fast, the actual drying speed is slow, and the overall curing reaction time is longer, which is difficult to meet the requirements of marine construction environment, especially underwater environment. Summary of the Invention

[0004] In view of this, the present invention proposes a bio-based epoxy resin coating for marine engineering and a preparation method thereof to solve the problem in the prior art that the coating has a long curing reaction time and is difficult to meet the requirements of the marine construction environment.

[0005] The technical solution of the present invention is achieved as follows: On the one hand, the present invention provides a bio-based epoxy resin coating for marine engineering, wherein the bio-based epoxy resin coating for marine engineering is composed of two components A and B, which are calculated in parts by weight.

[0006] Component A includes the following components: 30-32 parts of bio-based epoxy resin, 6-8 parts of reactive diluent, 0.2-0.4 parts of defoamer, 0.2-0.4 parts of dispersant, 1.6-1.8 parts of anti-settling agent, 44-48 parts of filler, 4-6 parts of zinc phosphate, and 7-9 parts of aluminum tripolyphosphate;

[0007] Component B includes the following components: 0.4-0.6 parts of drying agent and 25-28 parts of curing agent.

[0008] On the basis of the above technical solution, preferably, the bio-based epoxy resin in component A is magnolol-based epoxy resin.

[0009] Bio-based epoxy resins are generally biodegradable, helping to reduce environmental pollution and meet the requirements of sustainable development. Magnolia officinalis is extracted from the naturally occurring plant Magnolia officinalis and is renewable. Using magnolia officinalis as a raw material in the production of bio-based epoxy resins can reduce carbon emissions, contributing to lower greenhouse gas emissions and helping to address climate change. Bio-based epoxy resins generally possess excellent physical and chemical properties and can be used to prepare high-performance coatings, adhesives, composites, and more, meeting the needs of various industrial applications.

[0010] On the basis of the above technical solution, preferably, the molecular weight of the magnolia phenol-based epoxy resin is 2400-6500.

[0011] In general, epoxy resins with higher molecular weights can usually have higher viscosity, and this is because the epoxy resin molecular chain of high molecular weight is longer, and the intermolecular interaction force is larger, thereby causes higher viscosity. The molecular weight range of magnolia phenol-based epoxy resin is that the corresponding viscosity of 2400-6500 is moderate. For coating, epoxy resins with moderate viscosity are usually easier to construct, and epoxy resins with moderate viscosity can provide good fluidity and coating performance in coating, thereby is conducive to coating and uniformity in construction process. In addition, epoxy resins with moderate viscosity are also conducive to dispersion and stability with other components such as pigment, filler. On the other hand, high molecular weight epoxy resins have good curing properties usually, can provide more cross-linking points in curing process, thereby form more solid network structure. For the magnolia phenol-based epoxy resin with molecular weight range of 2400-6500, suitable viscosity and good curing properties can be taken into account in coating applications. Therefore, the coating with the addition of this magnolia phenol-based epoxy resin can meet the requirement of marine construction environment, especially underwater environment in coating construction and curing process.

[0012] On the basis of the above technical solution, preferably, the preparation method of the magnolol-based epoxy resin comprises the following steps:

[0013] S1, weighing 26-27 parts of magnolol, 73-75 parts of epichlorohydrin, and 4.8-5.5 parts of benzyltriethylammonium chloride in parts by weight, adding them to a reactor, heating at 90-110° C. for 55-65 min, then adding them to an aqueous sodium hydroxide solution prepared by 15-16.5 parts of sodium hydroxide and 145-160 parts of deionized water, heating at 28-32° C. for 80-100 min, and purifying by chromatography to obtain diepoxy magnolol, the structural formula of which is

[0014] ;

[0015] S2, weighing 37-38.5 parts of the product of step S1, 28-29.2 parts of acrylic acid, 3-4 parts of ruthenium, and 5.5-6.5 parts of dimethyl carbonate, in parts by weight, adding them to a reaction kettle, heating at 78-83°C for 2.5-3.5h, and chromatographically purifying to obtain diacrylate-diepoxy magnolol, the structural formula of which is

[0016] ;

[0017] S3. Weigh 25-27 parts of the product of step S2 and 24-26 parts of toluene in parts by weight and add them to a reactor, introduce oxygen to 0.09-0.12 MPa, and heat at 120-140° C. for 3.5-4.5 h to obtain a magnolol-based epoxy resin.

[0018] On the basis of the above technical solution, preferably, in step S3, before the oxygen is introduced to 0.09-0.12 MPa, nitrogen is introduced to replace and remove the air in the reactor.

[0019] On the basis of the above technical solution, preferably, the reactive diluent includes at least one of propenyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, propylene oxide propenyl ether, glycidyl methacrylate and benzyl glycidyl ether.

[0020] On the basis of the above technical solution, preferably, the filler includes at least one of zinc chromate, iron oxide, talc, barium sulfate, titanium dioxide, carbon black, nano-TiO2, aluminum oxide, mica powder, porcelain powder and quartz powder.

[0021] On the basis of the above technical solution, preferably, the anti-settling agent includes at least one of organic bentonite, montmorillonite and polyamide wax.

[0022] Based on the above technical solution, preferably, the defoaming agent includes at least one of silicone solution, modified silicone polyether, and polydimethylsiloxane, and the dispersant includes at least one of polyethylene glycol, polypropylene glycol, amino compounds, and ethylene oxide.

[0023] On the basis of the above technical solution, preferably, the drying agent is DMP30, and the curing agent is phenalkamine curing agent.

[0024] DMP-30 (dimethylphenol peroxide) is a commonly used drier primarily used in coatings, adhesives, and resin systems. DMP-30's catalytic effect is achieved through the decomposition of peroxides to generate free radicals. When exposed to heat or chemical stimulation, peroxides decompose, generating reactive free radicals that initiate crosslinking reactions in the coating, ultimately curing it. As a catalyst, DMP-30 promotes the decomposition of peroxides, increasing the rate of free radical generation and accelerating the coating's curing process. This rapid curing mechanism gives DMP-30 the advantages of fast curing, low-temperature curing, and improved coating performance. These advantages of DMP-30 are ideally suited to the unique requirements of marine environments, requiring the coating to cure rapidly at low temperatures and withstand water erosion.

[0025] The phenolic groups in phenalkamine curing agents react chemically with active groups in the coating to form a three-dimensional network structure, thereby improving the coating's chemical resistance. Since phenalkamine curing agents form cross-linked structures during the curing process, these cross-links strengthen the coating's intermolecular interactions and enhance its thermal stability. The cross-linked structures of phenalkamine curing agents also enhance the coating's weather resistance, maintaining good performance against natural environmental factors such as ultraviolet light, oxidation, and humidity. The cross-linked structures of phenalkamine curing agents also enhance the coating's hardness and wear resistance, making it less susceptible to damage from friction and wear. Overall, the molecular structure and curing reaction mechanism of phenalkamine curing agents enable them to form a strong cross-linked structure in the coating, imparting excellent properties such as chemical resistance, heat resistance, weather resistance, and wear resistance.

[0026] In another aspect, the present invention provides a method for preparing the above-mentioned bio-based epoxy resin coating for marine engineering, comprising the following steps:

[0027] S1. Mix and disperse the raw materials of component A evenly, and ball mill for 2.5 to 4 hours;

[0028] S2. The raw materials of component B are mixed and dispersed evenly, and then mixed with component A after ball milling in step S1, and dispersed evenly to obtain a bio-based epoxy marine anti-corrosion coating.

[0029] The bio-based epoxy resin coating for marine engineering and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0030] (1) The coating of the present invention contains a bio-based epoxy resin prepared by adding magnolol as a bio-based substance as a raw material. In view of the characteristics of the molecular structure of magnolol, an acrylic acid-based structure with high flexibility is introduced to adjust the flexibility and viscosity of the resin molecules, so that the paint film not only has high strength but also has good flexibility and can withstand long-term wave erosion;

[0031] (2) The molecular weight of the bio-based epoxy resin added to the coating of the present invention is between 2400 and 6500, and it has both low viscosity and a certain molecular weight, making the coating easy to apply and able to cure quickly;

[0032] (3) The magnolia phenol-based epoxy resin prepared by the present invention contains a large number of epoxy groups in its molecular structure. The resin with a high epoxy value can react with a large amount of curing agent during the curing process to form a denser network structure with a large cross-linking density and a dense structure. This structure makes the resin have higher hardness and water resistance after film formation, thereby making the coating more excellent in anti-corrosion performance. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is composed of two components A and B.

[0036] Component A includes the following components: 31.2g of magnolol-based epoxy resin, 7g of propylene glycidyl ether, 0.3g of polydimethylsiloxane, 0.3g of polyethylene glycol, 1.7g of organic bentonite, 46g of barium sulfate, 5g of zinc phosphate, and 8g of aluminum tripolyphosphate;

[0037] Component B includes the following components: DMP30 0.5g, T-31 curing agent 25g.

[0038] The preparation method of magnolia phenol-based epoxy resin comprises the following steps:

[0039] S1, weighing magnolol 26.6g, epichlorohydrin 74g, benzyltriethylammonium chloride 5g, adding them to a reactor, heating at 100°C for 60min, then adding them to a sodium hydroxide aqueous solution prepared by 16g of sodium hydroxide and 150g of deionized water, heating at 30°C for 90min, and purifying by chromatography to obtain diepoxy magnolol;

[0040] S2. Weigh 37.8 g of the product from step S1, 28.8 g of acrylic acid, 3.5 g of ruthenium, and 6 g of dimethyl carbonate, add them to a reaction kettle, heat at 80° C. for 3 h, and purify by chromatography to obtain diacrylate-diepoxymagnolia nobile;

[0041] S3. Weigh 26 g of the product from step S2 and 25 g of toluene into a reactor, introduce nitrogen for 0.5 h to replace and remove the air in the reactor, then introduce oxygen to 0.1 MPa, and heat at 130° C. for 4 h to obtain magnolol-based epoxy resin.

[0042] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, comprising the following steps:

[0043] S1. Mix and disperse the raw materials of component A evenly, and ball mill for 3 hours;

[0044] S2. The raw materials of component B are mixed and dispersed evenly, and then mixed with component A after ball milling in step S1, and dispersed evenly to obtain a bio-based epoxy marine anti-corrosion coating.

[0045] Example 2

[0046] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that in Example 1, except that:

[0047] The preparation method of magnolia phenol-based epoxy resin comprises heating at 100° C. for 4 hours in step S3.

[0048] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0049] Example 3

[0050] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that in Example 1, except that:

[0051] In the preparation method of magnolia phenol-based epoxy resin, in step S3, heating is performed at 120° C. for 4 hours.

[0052] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0053] Example 4

[0054] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that in Example 1, except that:

[0055] In the preparation method of magnolia phenol-based epoxy resin, in step S3, heating is performed at 140° C. for 4 hours.

[0056] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0057] Example 5

[0058] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that in Example 1, except that:

[0059] In the preparation method of magnolia phenol-based epoxy resin, in step S3, heating is performed at 150° C. for 4 hours.

[0060] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0061] Example 6

[0062] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1, except that no magnolol-based epoxy resin is added.

[0063] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0064] Example 7

[0065] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1, except that component A includes 25 g of magnolol-based epoxy resin.

[0066] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0067] Example 8

[0068] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1, except that component A includes 30 g of magnolol-based epoxy resin.

[0069] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0070] Example 9

[0071] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1, except that component A includes 32 g of magnolol-based epoxy resin.

[0072] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0073] Example 10

[0074] This embodiment provides a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1, except that component A includes 35 g of magnolol-based epoxy resin.

[0075] This embodiment provides a method for preparing a bio-based epoxy resin coating for marine engineering, which is the same as that of Example 1.

[0076] The coatings prepared in Examples 1 to 10 were sprayed or brushed onto steel plates at 25°C, respectively. After curing, smooth, dense, and uniform coatings were obtained. The adhesion, impact resistance, pencil hardness, flexibility, and corrosion resistance of the coatings were measured. The results are shown in Table 1.

[0077] Test method: Refer to the standard "GB / T1720-2020 Paint film circle test" to test the coating adhesion; refer to the standard "GB / T1732-2020 Paint film impact resistance determination method" to test the coating impact resistance; refer to the standard "GB / T6739-2006 Paint and varnish pencil method for determination of paint film hardness" to test the coating pencil hardness; refer to the standard "GBT / 1731-1993 Paint film flexibility determination method" to test the coating flexibility; refer to the standard "GB / T 10125-2021 Artificial atmosphere corrosion test salt spray test" to test the coating corrosion resistance.

[0078] Table 1 Coating performance test

[0079]

[0080] A comparison of Examples 1 to 5 shows that the heating temperature in the final step of the magnolia phenol-based epoxy resin synthesis reaction affects the properties of the resulting magnolia phenol-based epoxy resin, and thus the properties of the coating. Heating temperatures that are too low can significantly reduce the coating's adhesion and pencil hardness, and also reduce its corrosion resistance, but improve its flexibility. Heating temperatures that are too high can also reduce the coating's adhesion, impact resistance, pencil hardness, and corrosion resistance.

[0081] From the comparison between Example 1 and Example 6, it can be seen that the addition of magnolia phenol-based epoxy resin to the coating can significantly improve the adhesion, impact resistance, pencil hardness, flexibility and corrosion resistance of the coating.

[0082] From the comparison of Example 1 and Examples 7 to 10, it can be seen that as the amount of magnolia phenol-based epoxy resin added in the coating increases, the adhesion, impact resistance, pencil hardness, flexibility and corrosion resistance of the coating become increasingly excellent. However, when the amount of magnolia phenol-based epoxy resin added is too much, the impact resistance and corrosion resistance of the coating will be reduced.

[0083] 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, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bio-based epoxy resin coating for marine engineering, characterized by: The bio-based epoxy resin coating for marine engineering is composed of two components, A and B, which are calculated in parts by weight. Component A includes the following components: 30-32 parts of bio-based epoxy resin, 6-8 parts of reactive diluent, 0.2-0.4 parts of defoamer, 0.2-0.4 parts of dispersant, 1.6-1.8 parts of anti-settling agent, 44-48 parts of filler, 4-6 parts of zinc phosphate, and 7-9 parts of aluminum tripolyphosphate; Component B includes the following components: 0.4-0.6 parts of drying agent and 25-28 parts of curing agent; The bio-based epoxy resin in component A is magnolol-based epoxy resin; The preparation method of the magnolol-based epoxy resin comprises the following steps: S1, weighing 26-27 parts of magnolol, 73-75 parts of epichlorohydrin, and 4.8-5.5 parts of benzyltriethylammonium chloride in parts by weight, adding them to a reactor, heating at 90-110° C. for 55-65 min, then adding them to an aqueous sodium hydroxide solution prepared by 15-16.5 parts of sodium hydroxide and 145-160 parts of deionized water, heating at 28-32° C. for 80-100 min, and purifying by chromatography to obtain diepoxy magnolol, the structural formula of which is ； S2, weighing 37-38.5 parts of the product of step S1, 28-29.2 parts of acrylic acid, 3-4 parts of ruthenium, and 5.5-6.5 parts of dimethyl carbonate, in parts by weight, adding them to a reaction kettle, heating at 78-83°C for 2.5-3.5h, and chromatographically purifying to obtain diacrylate-diepoxy magnolol, the structural formula of which is ； S3. Weigh 25-27 parts of the product of step S2 and 24-26 parts of toluene in parts by weight and add them to a reactor, introduce oxygen to 0.09-0.12 MPa, and heat at 120-135° C. for 3.5-4.5 hours to obtain a magnolol-based epoxy resin.

2. The bio-based epoxy resin coating for marine engineering according to claim 1, characterized in that: The molecular weight of the magnolol-based epoxy resin is 2400-6500.

3. The bio-based epoxy resin coating for marine engineering according to claim 1, characterized in that: The reactive diluent includes at least one of propenyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, propylene oxide propenyl ether, glycidyl methacrylate and benzyl glycidyl ether.

4. The bio-based epoxy resin coating for marine engineering according to claim 1, wherein: The filler includes at least one of zinc chromate, iron oxide, talc, barium sulfate, titanium dioxide, carbon black, nano-TiO2, aluminum oxide, mica powder, porcelain powder and quartz powder.

5. The bio-based epoxy resin coating for marine engineering according to claim 1, wherein: The anti-settling agent includes at least one of organic bentonite, montmorillonite and polyamide wax.

6. The bio-based epoxy resin coating for marine engineering according to claim 1, characterized in that: The defoaming agent includes at least one of organic silicon solution, modified silicon polyether, and polydimethylsiloxane, and the dispersant includes at least one of polyethylene glycol, polypropylene glycol, amino compound, and ethylene oxide.

7. The bio-based epoxy resin coating for marine engineering according to claim 1, characterized in that: The drying agent is DMP30, and the curing agent is phenalkamine curing agent.

8. The method for preparing a bio-based epoxy resin coating for marine engineering according to any one of claims 1 to 7, wherein: The steps include: S1. Mix and disperse the raw materials of component A evenly, and ball mill for 2.5 to 4 hours; S2. The raw materials of component B are mixed and dispersed evenly, and then mixed with component A after ball milling in step S1, and dispersed evenly to obtain a bio-based epoxy marine anti-corrosion coating.

Images