A rhein-modified amine curing agent and its preparation method, and a long-lasting anti-corrosion coating based on bulk rust conversion and its preparation method and application.

Abstract

This invention discloses an emodin-modified amine curing agent and its preparation method, as well as a long-lasting anti-corrosion coating based on bulk rust conversion, its preparation method, and its application. It relates to the field of anti-corrosion coating technology. The preparation method of the emodin-modified amine curing agent of this invention includes: subjecting raw materials including 2-hydroxyemodin, formaldehyde, and 1,5-pentanediamine to a Mannich reaction to obtain the emodin-modified amine curing agent. The emodin-modified amine curing agent used in this invention has a certain rust conversion ability and forms a stable chelate with iron ions, eliminating the need for rust conversion agents and allowing direct application to corroded surfaces. By using a suitable resin and curing agent system ratio, this invention can prepare a high-performance, low-surface-treatment, long-lasting anti-corrosion coating based on bulk rust conversion, applicable to manually cleaned surfaces (St2 / St3, ISO 8501-1), old coatings, high-pressure water jetting, and wet sandblasting substrate surfaces.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, and more specifically, to a rhein-modified amine curing agent and its preparation method, and a long-lasting anti-corrosion coating based on bulk rust conversion and its preparation method and application. Background Technology

[0002] Weathering steel and carbon steel, widely used in existing industries, still exhibit localized or large-area rusting despite the application of anti-corrosion coating systems. Surface sandblasting to Sa2.5 is required before secondary coating. Low-surface-treatment anti-corrosion coatings can be applied to rusted or wet surfaces and are suitable for steel substrates with a St2 rating or higher. However, due to severe substrate corrosion, traditional low-surface-treatment coatings cannot achieve the same anti-corrosion effect as those applied after substrate treatment. In recent years, rust-converting agents have been widely used in industry. These agents can coordinate or reduce rust to form stable oxides. Applying a second anti-corrosion primer significantly improves the anti-corrosion effect.

[0003] Existing rust converters generally use one of tannic acid, gallic acid, or phytic acid, combined with phosphoric acid or phosphates to form the effective rust-converting component, which is then compounded or modified into an aqueous emulsion. Commercially available rust converters are water-based systems, and when applied to steel substrates with minimal surface treatment, they show relatively significant rust conversion effects. However, some problems still exist in their application: the rust-converting film may crack, posing a risk of later penetration and re-corrosion; and a primer needs to be applied after using the rust converter, adding a second application step and extending the construction period. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an emodin-modified amine curing agent and its preparation method, as well as a long-lasting anti-corrosion coating based on bulk rust conversion, its preparation method, and its application. The emodin-modified amine curing agent used in this invention possesses a certain rust conversion ability and forms a stable chelate with iron ions, eliminating the need for rust conversion agents and allowing direct application to corroded surfaces. By using a suitable resin and curing agent system ratio, this invention can prepare a high-performance, low-surface-treatment, long-lasting anti-corrosion coating based on bulk rust conversion. It can be applied to manually cleaned surfaces (St2 / St3, ISO 8501-1), old coatings, high-pressure water jetting, and wet sandblasting substrates. It exhibits excellent performance in salt spray resistance, cathodic disbondment resistance, damp heat resistance, and solvent resistance, with a film anti-corrosion period of 15-20 years.

[0005] One of the objectives of this invention is to provide a rhein-modified amine curing agent.

[0006] The emodin-modified amine curing agent of the present invention has the following structural formula: .

[0007] A second objective of this invention is to provide a method for preparing the emodin-modified amine curing agent as described in one objective of this invention.

[0008] The preparation method of the rhein-modified amine curing agent of the present invention includes: The emodin-modified amine curing agent is prepared by subjecting raw materials including 2-hydroxyemodin, formaldehyde, and 1,5-pentanediamine to a Mannich reaction; preferably, (1) Under a protective atmosphere, 2-hydroxyemodin and part of 1,5-pentanediamine were heated and dissolved in a solvent, a catalyst was added, and a first high-speed dispersion was carried out to obtain a first mixture; (2) After adding some formaldehyde to the first mixture, a first heating reaction is carried out to obtain the first reactant; (3) After the first reactant is cooled, the remaining 1,5-pentanediamine is added for a second high-speed dispersion to obtain a second mixture; (4) Add the remaining formaldehyde dropwise to the second mixture and carry out the second heating reaction to obtain the second reactant; (5) After the second reactant is cooled down, it is distilled under reduced pressure to remove unreacted monomers, an epoxy diluent is added, the solid content is adjusted, and then it is cooled to room temperature to obtain the emodin-modified amine curing agent.

[0009] In a preferred embodiment of the present invention: In steps (1) and (2), the molar ratio of 2-hydroxyemodin, a portion of formaldehyde, and a portion of 1,5-pentanediamine is 2:(1.7~2.3):(0.8~1.2), preferably 2:(1.8~2.2):(0.9~1.1); and / or, In step (1), the molar ratio of 2-hydroxyemodin to the solvent is 1:(4~10), preferably 1:(5~6); and / or, The catalyst is 0.1~1 mol, preferably 0.1~0.2 mol; and / or, In steps (3) and (4), the molar ratio of the first reactant, the remaining formaldehyde, and the remaining 1,5-pentanediamine is 1:(1.7~2.3):(1.7~2.3), preferably 1:(1.8~2.2):(1.8~2.2); and / or, In step (5), the solid content is 50-60 wt%.

[0010] In a preferred embodiment of the present invention: In step (1), the solvent is an alcohol solvent, preferably butanol; and / or, the catalyst is concentrated hydrochloric acid; and / or, In step (5), the epoxy diluent is a commonly used epoxy diluent in the art.

[0011] In a preferred embodiment of the present invention: In step (1), the rotational speed of the first high-speed dispersion is 600–1000 rd / min; and / or, In step (2), the temperature of the first heating reaction is 65–120°C, preferably 70–110°C, and / or the time is 1.5–5 h, preferably 2–4 h; and / or, In step (3), the temperature of the first reactant after cooling is 40–60°C; and / or, the second high-speed dispersion time is 20–30 min; and / or, the rotation speed is 600–1000 rd / min; and / or, In step (4), the temperature of the second heating reaction is 65–120°C, preferably 70–110°C, and / or the time is 1.5–5 h, preferably 2–4 h; and / or, In step (5), the temperature of the second reactant after cooling is 50-60°C.

[0012] The emodin-modified amine curing agent of the present invention is obtained by the Mannich reaction of 2-hydroxyemodin, formaldehyde, and 1,5-pentanediamine. By introducing a polyphenol structure, the two lone pair electrons in the oxygen atom of the phenolic hydroxyl group can form a -CO-Fe- bond with the d orbital of the iron atom, chelating to form a stable coordination compound containing iron, thereby achieving the purpose of rust transformation.

[0013] The specific reaction equation is as follows:

[0014] The third objective of this invention is to provide a long-lasting anti-corrosion coating based on the body's rust-transfer mechanism.

[0015] The long-lasting anti-corrosion coating based on bulk rust conversion described in this invention comprises component A and component B. Component A, by weight, comprises: 100 parts by weight of bisphenol A type epoxy resin (BPA type epoxy resin); 3-25 parts by weight of reactive diluent; 25-45 parts by weight of active rust-preventive pigment; Corrosion inhibitor 0-10 parts by weight; Pigments and fillers: 80-160 parts by weight; 5-30 parts by weight of additives; 10-40 parts by weight of epoxy diluent; Component B, by weight, comprises: 100 parts by weight of modified epoxy curing agent; Curing accelerator: 0-15 parts by weight; The weight ratio of component A to component B is (5~12):1; The modified epoxy curing agent includes the emodin-modified amine curing agent as described in one objective of the present invention or the emodin-modified amine curing agent prepared by the method described in another objective of the present invention, and optionally at least one of aliphatic amines, cycloaliphatic amines, phenolic amines, polyamides, and modified amine curing agents.

[0016] In a preferred embodiment of the present invention: Component A, by weight, comprises: 100 parts by weight of bisphenol A type epoxy resin; 5-20 parts by weight of reactive diluent; 30-40 parts by weight of active rust-preventive pigment; Corrosion inhibitor 2-8 parts by weight; Pigments and fillers: 90-120 parts by weight; 8-20 parts by weight of auxiliary agent; 15-30 parts by weight of epoxy diluent; Component B, by weight, comprises: 100 parts by weight of modified epoxy curing agent; Curing accelerator: 0-8 parts by weight; The weight ratio of component A to component B is (6~10):1.

[0017] In a preferred embodiment of the present invention: The reactive diluent is a glycidyl ether containing aliphatic chains and / or ether chains. Preferably, the glycidyl ether is a trifunctional or tetrafunctional glycidyl ether. More preferably, the reactive diluent is at least one of 3-(epoxyethylene methoxy)-2,2-di[(epoxyethylene methoxy)methyl]propanol, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, glycerol propoxy triglycidyl ether, castor oil glycidyl ether, and pentaerythritol glycidyl ether; and / or, The active rust-inhibiting pigment is at least one of the following: zinc phosphate, modified zinc phosphate, composite zinc phosphate, aluminum tripolyphosphate, modified aluminum tripolyphosphate, calcium phosphate, zinc aluminum phosphate, zinc aluminum molybdenum phosphate, zinc aluminum orthophosphate, strontium aluminum polyphosphate, zinc molybdenum polyphosphate, calcium aluminum polyphosphate, calcium phosphosilicate, strontium phosphosilicate, barium phosphosilicate, zinc strontium phosphosilicate, calcium strontium phosphosilicate, zinc aluminum strontium phosphosilicate, zinc phosphomolybdate, aluminum zinc phosphomolybdate, zinc strontium phosphostrontium, and zinc molybdate; and / or, The corrosion inhibitor is a commonly used corrosion inhibitor in the art; and / or, The pigments and fillers are at least one of the following: carbon black, iron oxide red, iron oxide yellow, chrome yellow, ultramarine, iron blue, titanium green, rutile titanium dioxide, kaolin, talc, mica powder, wollastonite powder, precipitated barium sulfate, silica fume, composite iron-titanium powder, ferrophosphate powder, heavy calcium carbonate, light calcium carbonate, calcite powder, feldspar powder, montmorillonite, polytetrafluoroethylene powder, mica iron oxide, non-floating aluminum powder, glass flakes, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithium magnesium silicate, organobentonite, wax powder, and fumed silica. These pigments and fillers can improve the corrosion resistance and hardness of the paint film, increase its sealing properties, reduce roughness, improve its hiding power, prevent settling, and adjust the viscosity of the slurry; and / or, The additive is at least one of wetting and dispersing agents, thixotropic agents, leveling agents, and defoamers, which may be added by technicians according to actual conditions; and / or, The epoxy diluent is a polar solvent, preferably at least one selected from ethylene glycol butyl ether acetate, ethylene glycol diacetate, propylene glycol methyl ether acetate, propylene glycol diacetate, divalent ester (DBE), R-3-hydroxybutyrate-R-3-hydroxybutyl ester, decanoate, diacetyl ester, ethyl 2-methylvalerate, and 1,3-nonanediol acetate; and / or, The curing accelerator is a small molecule polyamine.

[0018] The fourth objective of this invention is to provide a method for preparing a long-lasting anti-corrosion coating based on bulk rust transfer, as described in the third objective of this invention.

[0019] The method for preparing a long-lasting anti-corrosion coating based on bulk rust conversion according to the present invention includes: Component A is prepared by mixing the components in the specified weight proportions; Component B is prepared by mixing the components in the specified weight proportions; and the anti-corrosion coating is prepared by mixing the components A and B in the specified weight ratio.

[0020] The following solutions can be adopted: Component A: BPA-type epoxy resin, reactive diluent, additives, and epoxy diluent components are dispersed using a high-speed disperser at a stirring speed of 600–2000 r / min for approximately 10–30 min; then, reactive anti-rust pigments and filler components are gradually added, and dispersion continues for 30–60 min; the fineness is controlled to ≤40 μm, then filtered, discharged, and packaged.

[0021] Component B is mixed according to the stated dosage and dispersed using a high-speed disperser at a stirring speed of 600–2000 r / min for approximately 10–40 min. After filtration, the product is discharged and packaged.

[0022] When in use, the long-lasting anti-corrosion coating based on bulk rust conversion is prepared by mixing component A and component B in a certain proportion.

[0023] The fifth objective of this invention is to provide an application of a long-lasting anti-corrosion coating based on substrate rust conversion as described in the third objective of this invention, or a long-lasting anti-corrosion coating based on substrate rust conversion prepared by the method provided in the fourth objective of this invention, in the field of corrosion protection, preferably in the fields of construction, industry, petrochemicals, steel structures, bridges, etc.; it can be applied to manually cleaned surfaces (St2 / St3, ISO 8501-1), old coatings, high-pressure water jetting, wet sandblasting substrate surfaces.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The rhein-modified amine curing agent used in this invention has a certain rust conversion ability and forms a stable chelate with iron ions, which can eliminate the need for rust conversion agents and be directly applied to the corroded surface.

[0025] (2) The low surface treatment long-lasting anti-corrosion coating based on the body rust conversion of the present invention has the advantages of good anti-corrosion, salt spray resistance, damp heat resistance, solvent resistance and high adhesion.

[0026] (3) The low surface treatment long-lasting anti-corrosion coating based on the body rust conversion of the present invention can be applied to manually cleaned surfaces (St2 / St3, ISO 8501-1), old coatings, high-pressure water jetting, wet sandblasting substrate surfaces. The construction can be carried out by roller coating, brush coating, air spraying, airless spraying, etc. The effective life of the paint film is as long as 15 to 20 years.

[0027] (4) The coating of the present invention is not only simple to process and easy to industrialize, but also has good stability.

[0028] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships, such as A and / or B. Specifically, it can mean that A and B can be included at the same time, A can exist alone, or B can exist alone, and any of the above three situations can be met.

[0029] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0031] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0032] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0033] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0034] In the embodiments of the present invention, the rotation speed and temperature cannot be kept at a fixed value in actual operation due to the limitations of the experimental instruments, and fluctuate within a small range. The following embodiments are also in the same situation, and will not be described again later.

[0035]

Example 1

[0036] Preparation of low-surface-treatment, long-lasting anti-corrosion coatings based on bulk rust conversion: Component A BPA-type epoxy resin EPIKOTE 1001:100 parts by weight, American Hensen; 20 parts by weight of glycerol triglycidyl ether, Tesco Chemicals; HEUCOPHOS® ZPA 20 parts by weight, zinc aluminum orthophosphate; 20 parts by weight of Heubach aluminum strontium polyphosphate HEUCOPHOS® SAPP; Corrosion inhibitor HEUCORIN® RZ 4 parts by weight Heubach; HALOX® corrosion inhibitor 6304 parts by weight; 5 parts by weight of Borla carbon black; 20 parts by weight of titanium dioxide from Chemours; Montmorillonite, 15 parts by weight, Chengdu Jialong; 50 parts by weight of 1250 mesh talc powder, Hongde colored sand; Wetting and dispersing agent ADDITOL® XW 65652 parts by weight of Allnex; Thixotropic agent THIXATROL® PLUS 2 parts by weight Elementis; Leveling agent BYK-3350 2 parts by weight BYK; Defoamer EFKA PB 20012 parts by weight BASF; 15 parts by weight of ethylene glycol diacetate from Shanghai Yuanye; 5 parts by weight of glyceryl diacetate (Shanghai Civic); 10 parts by weight of propylene glycol methyl ether acetate; Component B 100 parts by weight of emodin-modified amine curing agent; Preparation of Component A: Disperse BPA-type epoxy resin, reactive diluent, additives, and epoxy diluent components using a high-speed disperser at a stirring speed of 600-800 r / min for about 30 min; then gradually add reactive anti-rust pigments and filler components, and continue dispersing for 60 min; control the fineness to ≤40 μm, filter, and package the material.

[0037] Component B is packaged and used directly; Components A and B are mixed in a weight ratio of 6:1 to prepare a long-lasting anti-corrosion coating with low surface treatment based on the body's rust-transfer mechanism.

[0038]

Example 2

[0039] Preparation of low-surface-treatment, long-lasting anti-corrosion coatings based on bulk rust conversion: Component A BPA-type epoxy resin SM61850 parts by weight, Jiangsu Sanmu; BPA-type epoxy resin YN182 150 parts by weight, Yangnong Chemical; 5 parts by weight of castor oil glycidyl ether (Anhui Xinyuan Technology); Calcium phosphate HEUCOPHOS® CMP 10 parts by weight Heubach; Heubach® Zinc Aluminum Molybdenum Phosphate (HEUCOPHOS® ZAM PLUS 10 parts by weight); HALOX® 70010 parts by weight of aluminum zinc phosphate; HALOX® corrosion inhibitor 6502 parts by weight; 20 parts by weight of mica iron oxide from Zhejiang Huayuan Pigment; 30 parts by weight of titanium dioxide from Zhongnu Titanium Dioxide; 10 parts by weight of ultrafine wollastonite powder from Aote Technology; 30 parts by weight of kaolin from Shanxi Jinyu Kelin; Light calcium carbonate, 30 parts by weight, from Shandong Yuxin; Dispex Ultra FA 44258 parts by weight, a wetting and dispersing agent from BASF. Thixotropic agent CRAYVALLAC OPTIM 4 parts by weight Arkema; Leveling agent A-30335 parts by weight of AFCONA; Defoamer ADDITOL® XL 65073 parts by weight Allnex; 5 parts by weight of ethyl 2-methylvalerate (Jilang Chemical); 5 parts by weight of R-3-hydroxybutyric acid-R-3-hydroxybutyl ester (Shanghai Maclean); 5 parts by weight of propylene glycol diacetate, Jusheng Technology; Component B 100 parts by weight of emodin-modified amine curing agent; Newdian Chemicals: 5 parts by weight of curing accelerator DBU; Preparation of Component A: Disperse BPA-type epoxy resin, reactive diluent, additives, and epoxy diluent components using a high-speed disperser at a stirring speed of 1800-2000 r / min for about 10 min; then gradually add reactive anti-rust pigments and filler components, and continue dispersing for 30 min; control the fineness to ≤40μm, filter, and package the material.

[0040] Preparation of component B: Mix according to the stated dosage, disperse using a high-speed disperser at a stirring speed of 600-800 r / min for about 40 min, filter, and then discharge and package.

[0041] Components A and B are mixed in a weight ratio of 9:1 to prepare a long-lasting anti-corrosion coating with low surface treatment based on the body's rust-transfer mechanism.

[0042]

Example 3

[0043] Preparation of low-surface-treatment, long-lasting anti-corrosion coatings based on bulk rust conversion: Component A BPA-type epoxy resin YD-114F 70 parts by weight; BPA-type epoxy resin EPIKOTE 834, 30 parts by weight, from Henson Chemicals, USA; 15 parts by weight of glycerol propoxytriglycidyl ether, Hubei Wande Chemical Co., Ltd. HEUCOPHOS® ZAPP 8 parts by weight (containing zinc molybdenum polyphosphate) from Heubach. Strontium zinc phosphosilicate HALOX® SZP-391 16 parts by weight HALOX; HALOX® Zinc Phosphate, 8 parts by weight; HALOX® 550 WF corrosion inhibitor, 4 parts by weight; Iron oxide red (Red 130M) in 10 parts by weight (BAYFERROX); 20 parts by weight of titanium dioxide from Jiangsu Taibai; Precipitated barium sulfate, 3000 mesh, 50 parts by weight, from Baifeng Chemical Co., Ltd. 20 parts by weight of silicon micropowder, Sibico; Non-floating aluminum powder PC150 10 parts by weight ECKART; Wetting and dispersing agent Tego Dispers 715W 6 parts by weight Evonik; Thixotropic agent CRAYVALLAC SLT 1 part by weight Arkema; Leveling agent BYK-333, 3 parts by weight BYK; Antifoam 3062 defoamer, 2 parts by weight, Evonik; 15 parts by weight of propylene glycol diacetate, Morinaga, Japan; 5 parts by weight of 1,3-nonanediol acetate, Red Star Flavor; 5 parts by weight of decyl decanoate (Shanghai Maclean); Component B 60 parts by weight of emodin-modified amine curing agent; Epoxy curing agent LITE 3100: 40 parts by weight of Cardolite; Preparation of Component A: Disperse the BPA-type epoxy resin, reactive diluent, additives, and epoxy diluent components using a high-speed disperser at a stirring speed of 800-1000 r / min for about 20 min; then gradually add the reactive anti-rust pigment and pigment / filler components, and continue dispersing for 40 min; control the fineness to ≤40 μm, filter, and discharge for packaging.

[0044] Preparation of component B: Mix according to the stated dosage, disperse using a high-speed disperser at a stirring speed of 1800-2000 r / min for about 20 min, filter, and then discharge and package.

[0045] Components A and B are mixed in a weight ratio of 7:1 to prepare a long-lasting anti-corrosion coating with low surface treatment based on the body's rust-transfer mechanism.

[0046]

Example 4

[0047] Preparation of low-surface-treatment, long-lasting anti-corrosion coatings based on bulk rust conversion: Component A 100 parts by weight of BPA-type epoxy resin NPEL from Nanya; 10 parts by weight of trimethylolpropane triglycidyl ether (Shanghai Fushun); Strontium Calcium Zinc Phosphate Silicate HEUCOPHOS® ZCP PLUS 12 parts by weight Heubach; Strontium aluminum polyphosphate HEUCOPHOS® SRPP 12 parts by weight Heubach; Strontium zinc phosphosilicate HALOX® SZP-395 12 parts by weight; Corrosion inhibitor HEUCORIN® RZ 6 parts by weight Heubach; 10 parts by weight of iron oxide yellow from Hunan Sanhuan; Titanium dioxide, 25 parts by weight, from Ishihara, Japan; 30 parts by weight of Huayuan Mica powder; 25 parts by weight of feldspar powder from Anhui Gerui; 10 parts by weight of polytetrafluoroethylene powder from Hangzhou Bolong; Wetting and dispersing agent Efka PU 40636 parts by weight BASF; Thixotropic agent BENTONE 38VCG 2 parts by weight Elementis; Leveling agent MODAFLOW® LAMBDA 4 parts by weight Allnex; Defoamer EFKA PB 2741 4 parts by weight BASF; 5 parts by weight of propylene glycol methyl ether acetate; 10 parts by weight of divalent ester DBE Invista; 5 parts by weight of diethylene glycol butyl ether acetate EASTMAN; Component B Epoxy curing agent Aradur 45080 parts by weight Huntsman; 20 parts by weight of emodin-modified amine curing agent; Curing accelerator CUREZOL 2MZ-A8 parts by weight, Shikoku Chemical, Japan; Component A: BPA-type epoxy resin, reactive diluent, additives, and epoxy diluent components are dispersed in a high-speed disperser at a stirring speed of 1600-1800 r / min for about 20 minutes; then, reactive anti-rust pigments and filler components are gradually added, and dispersion is continued for another 50 minutes; the fineness is controlled to be ≤40μm, filtered, and then discharged and packaged.

[0048] Component B is mixed according to the stated dosage, dispersed for about 10 minutes using a high-speed disperser at a stirring speed of 1600-1800 r / min, filtered, and then packaged.

[0049] Use components A and B in a weight ratio of 10:1.

[0050] Comparative Example 1 Preparation of anti-corrosion coatings: Component A BPA-type epoxy resin SM61850 parts by weight, Jiangsu Sanmu; BPA-type epoxy resin YN182 150 parts by weight, Yangnong Chemical; 5 parts by weight of castor oil glycidyl ether (Anhui Xinyuan Technology); Calcium phosphate HEUCOPHOS® CMP 10 parts by weight Heubach; Heubach® Zinc Aluminum Molybdenum Phosphate (HEUCOPHOS® ZAM PLUS 10 parts by weight); HALOX® 70010 parts by weight of aluminum zinc phosphate; HALOX® corrosion inhibitor 6502 parts by weight; 20 parts by weight of mica iron oxide, Zhejiang Huayuan Pigment 30 parts by weight of titanium dioxide from Zhongnu Titanium Dioxide; 10 parts by weight of ultrafine wollastonite powder from Aote Technology; 30 parts by weight of kaolin from Shanxi Jinyu Kelin; Light calcium carbonate, 30 parts by weight, from Shandong Yuxin; Dispex Ultra FA 44258 parts by weight, a wetting and dispersing agent from BASF. Thixotropic agent CRAYVALLAC OPTIM 4 parts by weight Arkema; Leveling agent A-30335 parts by weight of AFCONA; Defoamer ADDITOL® XL 65073 parts by weight Allnex; 5 parts by weight of ethyl 2-methylvalerate (Jilang Chemical); 5 parts by weight of R-3-hydroxybutyric acid-R-3-hydroxybutyl ester (Shanghai Maclean); 5 parts by weight of propylene glycol diacetate, Jusheng Technology; Component B Epoxy curing agent JT-6015A 80 parts by weight, Shanghai Jingtian; Epoxy curing agent PLR 71520 parts by weight, Changshu Naisu; Accelerator 960 - 15 parts by weight Huntsman; Components A and B are used in a weight ratio of 9:1.

[0051] The coatings prepared in the above embodiments and comparative examples were tested, and the results are shown in Table 1 below.

[0052] Table 1

[0053] In summary, the long-lasting anti-corrosion coating with low surface treatment based on bulk rust conversion prepared in the embodiments of the present invention has excellent performance; the coating film applied to low surface treatment (St2, St3) has better performance than the comparative example in terms of adhesion, salt spray resistance, and cathodic disbondment resistance. The long-lasting anti-corrosion coating with low surface treatment based on bulk rust conversion of the present invention has optimized and adjusted the structure of the film-forming material, resulting in high anti-corrosion efficiency.

[0054] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A rhein-modified amine curing agent, characterized in that... The structural formula of the emodin-modified amine curing agent is: 。 2. A method for preparing the emodin-modified amine curing agent as described in claim 1, characterized in that... The method includes: The emodin-modified amine curing agent is prepared by subjecting raw materials including 2-hydroxyemodin, formaldehyde, and 1,5-pentanediamine to a Mannich reaction; preferably, (1) Under a protective atmosphere, 2-hydroxyemodin and part of 1,5-pentanediamine were heated and dissolved in a solvent, a catalyst was added, and a first high-speed dispersion was carried out to obtain a first mixture; (2) After adding some formaldehyde to the first mixture, a first heating reaction is carried out to obtain the first reactant; (3) After the first reactant is cooled, the remaining 1,5-pentanediamine is added for a second high-speed dispersion to obtain a second mixture; (4) Add the remaining formaldehyde dropwise to the second mixture and carry out the second heating reaction to obtain the second reactant; (5) After the second reactant is cooled, it is distilled under reduced pressure, an epoxy diluent is added, and the solid content is adjusted to obtain the emodin-modified amine curing agent.

3. The method according to claim 2, characterized in that: In steps (1) and (2), the molar ratio of 2-hydroxyemodin, a portion of formaldehyde, and a portion of 1,5-pentanediamine is 2:(1.7~2.3):(0.8~1.2), preferably 2:(1.8~2.2):(0.9~1.1); and / or, The catalyst is 0.1~1 mol, preferably 0.1~0.2 mol; and / or, In step (1), the molar ratio of 2-hydroxyemodin to the solvent is 1:(4~10), preferably 1:(5~6); and / or, In steps (3) and (4), the molar ratio of the first reactant, the remaining formaldehyde, and the remaining 1,5-pentanediamine is 1:(1.7~2.3):(1.7~2.3), preferably 1:(1.8~2.2):(1.8~2.2); and / or, In step (5), the solid content is 50-60 wt%.

4. The method according to claim 2, characterized in that: In step (1), the solvent is an alcohol solvent, preferably butanol; and / or, the catalyst is concentrated hydrochloric acid.

5. The method according to claim 2, characterized in that: In step (1), the rotational speed of the first high-speed dispersion is 600–1000 rd / min; and / or, In step (2), the temperature of the first heating reaction is 65–120°C, preferably 70–110°C, and / or the time is 1.5–5 h, preferably 2–4 h; and / or, In step (3), the temperature of the first reactant after cooling is 40–60°C; and / or, the second high-speed dispersion time is 20–30 min; and / or, the rotation speed is 600–1000 rd / min; and / or, In step (4), the temperature of the second heating reaction is 65–120°C, preferably 70–110°C, and / or the time is 1.5–5 h, preferably 2–4 h; and / or, In step (5), the temperature of the second reactant after cooling is 50-60°C.

6. A long-lasting anti-corrosion coating based on bulk rust conversion, characterized in that... The anti-corrosion coating consists of component A and component B; Component A, by weight, comprises: 100 parts by weight of bisphenol A type epoxy resin; 3-25 parts by weight of reactive diluent; 25-45 parts by weight of active rust-preventive pigment; Corrosion inhibitor 0-10 parts by weight; Pigments and fillers: 80-160 parts by weight; 5-30 parts by weight of additives; 10-40 parts by weight of epoxy diluent; Component B, by weight, comprises: 100 parts by weight of modified epoxy curing agent; Curing accelerator: 0-15 parts by weight; The weight ratio of component A to component B is (5~12):1; The modified epoxy curing agent includes the emodin-modified amine curing agent as described in claim 1 or the emodin-modified amine curing agent prepared by the method as described in any one of claims 2-5, and optionally at least one of aliphatic amines, cycloaliphatic amines, phenolic amines, polyamides, and modified amine curing agents.

7. The anti-corrosion coating according to claim 6, characterized in that: Component A, by weight, comprises: 100 parts by weight of bisphenol A type epoxy resin; 5-20 parts by weight of reactive diluent; 30-40 parts by weight of active rust-preventive pigment; Corrosion inhibitor 2-8 parts by weight; Pigments and fillers: 90-120 parts by weight; 8-20 parts by weight of auxiliary agent; 15-30 parts by weight of epoxy diluent; Component B, by weight, comprises: 100 parts by weight of modified epoxy curing agent; Curing accelerator: 0-8 parts by weight; The weight ratio of component A to component B is (6~10):

1.

8. The anti-corrosion coating according to claim 6 or 7, characterized in that: The reactive diluent is a glycidyl ether containing aliphatic chains and / or ether chains. Preferably, the glycidyl ether is a trifunctional or tetrafunctional glycidyl ether. More preferably, the reactive diluent is at least one of 3-(epoxyethylene methoxy)-2,2-di[(epoxyethylene methoxy)methyl]propanol, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, glycerol propoxy triglycidyl ether, castor oil glycidyl ether, and pentaerythritol glycidyl ether; and / or, The active rust-inhibiting pigment is at least one of the following: zinc phosphate, modified zinc phosphate, composite zinc phosphate, aluminum tripolyphosphate, modified aluminum tripolyphosphate, calcium phosphate, zinc aluminum phosphate, zinc aluminum molybdenum phosphate, zinc aluminum orthophosphate, strontium aluminum polyphosphate, zinc molybdenum polyphosphate, calcium aluminum polyphosphate, calcium phosphosilicate, strontium phosphosilicate, barium phosphosilicate, zinc strontium phosphosilicate, calcium strontium phosphosilicate, zinc aluminum strontium phosphosilicate, zinc phosphomolybdate, aluminum zinc phosphomolybdate, zinc strontium phosphostrontium, and zinc molybdate; and / or, The pigments and fillers are at least one of the following: carbon black, iron oxide red, iron oxide yellow, chrome yellow, ultramarine, iron blue, titanium green, rutile titanium dioxide, kaolin, talc powder, mica powder, wollastonite powder, precipitated barium sulfate, silica fume, composite iron-titanium powder, ferrophosphate powder, heavy calcium carbonate, light calcium carbonate, calcite powder, feldspar powder, montmorillonite, polytetrafluoroethylene powder, mica iron oxide, non-floating aluminum powder, glass flakes, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithium magnesium silicate, organobentonite, wax powder, and fumed silica; and / or, The additive is at least one selected from wetting and dispersing agents, thixotropic agents, leveling agents, and defoamers; and / or, The epoxy diluent is a polar solvent, preferably at least one selected from ethylene glycol butyl ether acetate, ethylene glycol diacetate, propylene glycol methyl ether acetate, propylene glycol diacetate, divalent ester, R-3-hydroxybutyrate-R-3-hydroxybutyl ester, decanoate, diacetyl ester, ethyl 2-methylvalerate, and 1,3-nonanediol acetate; and / or, The curing accelerator is a small molecule polyamine.

9. A method for preparing a long-lasting anti-corrosion coating based on bulk rust conversion as described in any one of claims 6-8, characterized in that... The method includes: Component A is prepared by mixing the components in the specified weight proportions; Component B is prepared by mixing the components in the specified weight proportions; and the anti-corrosion coating is prepared by mixing the components A and B in the specified weight ratio.

10. The application of a long-lasting anti-corrosion coating based on bulk rust conversion as described in any one of claims 6-8, or a long-lasting anti-corrosion coating based on bulk rust conversion prepared by the method described in claim 9, in the field of corrosion protection, preferably in the fields of building, industry, petrochemical, steel structure, and bridge corrosion protection.

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