Anticorrosive water-based paint and method for preparing the same

Abstract

The application discloses an anti-corrosion water-based paint and a preparation method thereof, and relates to the technical field of water-based paints. The anti-corrosion water-based paint comprises the following raw materials in parts by weight: 80-100 parts of water-based epoxy resin, 20-25 parts of a water-based curing agent, 1-3 parts of a curing accelerator, 1-2 parts of a dispersing agent, 2-3 parts of a film-forming aid, 0.5-1 part of a defoaming agent, 0.5-1 part of an anti-flash rust agent, and 60-80 parts of deionized water; the anti-corrosion water-based paint prepared by the application has excellent adhesion, corrosion resistance and leveling performance.

Description

Technical Field

[0001] This invention relates to the field of water-based coatings technology, specifically to an anti-corrosion water-based coating and its preparation method. Background Technology

[0002] With increasingly stringent global environmental regulations and growing public awareness of health and environmental protection, water-based coatings, due to their advantages such as low volatile organic compound content, non-toxicity, odorlessness, safety, and non-flammability, are gradually replacing traditional solvent-based coatings and becoming an important development direction in the field of industrial corrosion protection. However, water-based coatings, especially those based on epoxy and acrylic resins, still face many performance challenges. Traditional water-based coatings often suffer from insufficient adhesion after curing, resulting in poor bonding between the coating and the substrate and easy peeling. In terms of corrosion resistance, due to the high surface tension and easy residue of water, the coating has poor density and cannot effectively block the penetration of water vapor, oxygen, and corrosive media, leading to frequent early rust and blistering. In addition, poor leveling properties cause defects such as orange peel and brush marks on the coating surface, which not only affect the appearance but also create weak points for corrosion.

[0003] Chinese invention patent CN110591475A discloses an antibacterial and anti-corrosion waterborne coating and its preparation method. The raw material components of the antibacterial and anti-corrosion waterborne coating include: rare earth functionalized waterborne acrylic resin, waterborne acrylic resin, antibacterial and anti-corrosion nanospheres, tripropylene glycol butyl ether, leveling agent, wetting agent, defoamer, dispersant, multifunctional additive AMP-95, thickener and deionized water. The antibacterial and anti-corrosion waterborne coating prepared by this invention has dual functions of antibacterial and anti-corrosion. It can not only prevent chemical corrosion, but also effectively prevent biological corrosion. However, its leveling properties need to be improved. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an anti-corrosion water-based coating and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A corrosion-resistant water-based coating comprises the following raw materials in parts by weight:

[0007] Waterborne epoxy resin: 80-100 parts, waterborne curing agent: 20-25 parts, curing accelerator: 1-3 parts, dispersant: 1-2 parts, film-forming aid: 2-3 parts, defoamer: 0.5-1 part, anti-flash rust agent: 0.5-1 part, deionized water: 60-80 parts;

[0008] The film-forming aid is prepared by the following method:

[0009] S1: Linoleic acid reacts with dibromoneopentyl glycol to form a two-armed long-chain double-bonded compound.

[0010] S2: Two-arm long-chain double-bonded compounds react with dodecyl diethylene glycol ether to form four-arm long-chain double-bonded compounds.

[0011] S3: A four-armed long-chain double-bonded compound reacts with formic acid and hydrogen peroxide to form a four-armed epoxy compound.

[0012] S4: The four-armed epoxy compound reacts with isobutyric anhydride to generate a film-forming aid.

[0013] In step S1, the molar ratio of linoleic acid to dibromoneopentyl glycol is (2.1-2.3):1.

[0014] In step S2, the molar ratio of the two-arm long-chain double bond compound to dodecyl diethylene glycol ether is 1:(2.1-2.3).

[0015] In step S3, the molar ratio of the four-armed long-chain double bond compound to formic acid is 1:(4.1-4.3).

[0016] In step S4, the molar ratio of the four-armed epoxy compound to isobutyric anhydride is 1:(8.1-8.3).

[0017] The water-based curing agent is a water-based epoxy curing agent.

[0018] The curing accelerator is one of 2-ethyl-4-methylimidazol or 2,4,6-tris(dimethylaminomethyl)phenol.

[0019] The defoamer is TEGO® Airex 902W.

[0020] The flash rust inhibitor is THIF-3118 type flash rust inhibitor; the dispersant is one of sodium dodecyl sulfate and sodium tripolyphosphate.

[0021] A method for preparing an anti-corrosion water-based coating includes the following steps:

[0022] (1) Weigh the following by weight: waterborne epoxy resin: 80-100 parts, waterborne curing agent: 20-25 parts, curing accelerator: 1-3 parts, dispersant: 1-2 parts, film-forming aid: 2-3 parts, defoamer: 0.5-1 part, anti-flash rust agent: 0.5-1 part, deionized water: 60-80 parts;

[0023] (2) Mix waterborne epoxy resin, deionized water, dispersant, defoamer, 1 part film-forming aid and anti-flash rust agent, and stir evenly; then add waterborne curing agent, curing accelerator and the remaining film-forming aid, stir evenly, and let stand at room temperature to mature to obtain anti-corrosion waterborne coating.

[0024] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include:

[0025] The waterborne coating prepared by this invention exhibits excellent corrosion resistance, adhesion, and leveling properties. The added film-forming aid enhances the adhesion and leveling properties of the waterborne coating through the synergistic effect of its four-arm structure, long alkyl ether chains, and isobutyrate groups. The long alkyl ether chains enhance adhesion to the substrate through hydrophobic interactions and van der Waals forces, and release internal stress, preventing film shrinkage or peeling caused by stress concentration, thus enhancing adhesion. The isobutyrate groups are resistant to hydrolysis, have high stability, and can form strong hydrogen bonds with polar groups on the substrate surface or in the resin, enhancing the adhesion of the coating to metal and other substrates. Detailed Implementation

[0026] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0027] Example 1: Preparation of film-forming aid:

[0028] S1: Under nitrogen protection, 400 g xylene, 0.1 mol dibromoneopentyl glycol, and 0.21 mol linoleic acid were added to the reactor and stirred until homogeneous. The mixture was heated to 110 °C, and then 2 g p-toluenesulfonic acid was added. After reacting for 8 h (water generated during the reaction was removed using a water separator), the mixture was cooled to room temperature, and saturated sodium bicarbonate solution was slowly added to adjust the pH to neutral. The mixture was stirred thoroughly for 30 min, allowed to stand for separation, and the organic phase was transferred to a rotary evaporator. The evaporation was carried out at 70 °C for 3 h, and then vacuum dried at 70 °C for 10 h to obtain a two-arm long-chain double-bonded compound. The reaction equation is shown below:

[0029]

[0030] Its 1H NMR data are as follows:

[0031] 1 H NMR (400 MHz, Chloroform- d ) δ 5.55 – 5.36 (m, 8H), 4.29 (s, 4H), 3.46 (s, 4H), 2.42 – 2.32 (m, 8H), 2.09 – 1.97 (m, 8H), 1.63 – 1.51 (m, 4H), 1.36 – 1.23 (m, 28H), 0.95 – 0.84 (m, 6H).

[0032] S2: Add 800 ml of anhydrous acetonitrile, 0.23 mol of triethylamine, and 0.1 mol of a two-arm long-chain double bond compound to the reactor, stir and mix well, then slowly add 100 ml of anhydrous acetonitrile solution containing 0.21 mol of dodecyl diethylene glycol ether over 30 min. After the addition is complete, heat to reflux and react for 9 h. Filter, wash three times with deionized water (100 ml each time), distill under reduced pressure at 60 °C for 3 h, and dry under vacuum at 70 °C for 8 h to obtain a four-arm long-chain double bond compound; the reaction equation is shown below:

[0033]

[0034] Its 1H NMR data are as follows:

[0035] 1 H NMR (400 MHz, Chloroform- d ) δ 5.63 – 5.32 (m, 8H), 4.11 (s, 4H), 3.70 – 3.61 (m, 16H), 3.60 (s, 4H), 3.50 (t, J = 6.1 Hz, 4H), 2.48 – 2.23 (m,8H), 2.09 – 1.95 (m, 8H), 1.56 – 1.42 (m, 8H), 1.41 – 1.14 (m, 64H), 0.93 –0.78 (m, 12H).

[0036] S3: Add 500 ml of dichloromethane, 0.1 mol of a four-armed long-chain double bond compound, and 5 g of strong acid cation exchange resin to the reactor. Add 0.41 mol of formic acid and 50 g of a 30 wt% H₂O₂ mixed solution dropwise over 30 min. After stirring and mixing, react at room temperature for 6 h. Filter, cool to 0 °C, adjust the pH to neutral with saturated sodium bicarbonate solution, allow to stand for separation, collect the organic phase, wash with 200 ml of ice water, add 50 g of anhydrous sodium sulfate and dry for 30 min. Filter, distill under reduced pressure at 35 °C for 2 h, and purify by column chromatography using petroleum ether / ethyl acetate (eluting with a petroleum ether / ethyl acetate (V:V) ratio gradient from 10:1 to 3:1). Distill under reduced pressure at 35 °C for 4 h, and dry under vacuum at 50 °C for 10 h to obtain the four-armed epoxy compound. The reaction equation is shown below:

[0037]

[0038] Its 1H NMR data are as follows:

[0039] 1 H NMR (400 MHz, Chloroform- d) δ 4.11 (s, 4H), 3.72 – 3.62 (m, 16H), 3.60 (s, 4H), 3.50 (t, J = 6.1 Hz, 4H), 3.27 (q, J = 5.0 Hz, 4H), 3.18 (dt, J= 5.2, 4.1 Hz, 4H), 2.36 (t, J = 8.5 Hz, 4H), 2.18 (dt, J = 13.6, 5.0 Hz,2H), 2.01 – 1.70 (m, 6H), 1.65 – 1.51 (m, 12H), 1.50 – 1.37 (m, 4H), 1.35 –1.19 (m, 60H), 0.96 – 0.80 (m, 12H).

[0040] S4: Add 600 ml of DMF (N,N-dimethylformamide), 0.1 mol of a four-armed epoxy compound, 0.81 mol of isobutyric anhydride, and 10 g of a strong acid cation exchange resin to the reactor. Stir and mix thoroughly, heat to 115 °C, react for 11 h, cool to room temperature, filter, and then pour into 1000 ml of ice water. Stir, precipitate, centrifuge, collect the solid product, wash three times with deionized water (300 ml each time), and dry under vacuum at 50 °C for 12 h to obtain the film-forming aid. The reaction equation is shown below:

[0041]

[0042] Its 1H NMR data are as follows:

[0043] 1 H NMR (400 MHz, Chloroform- d ) δ 5.01 (q, J = 7.8 Hz, 4H), 4.88 (dt,J = 7.8, 6.1 Hz, 4H), 4.11 (s, 4H), 3.74 – 3.62 (m, 16H), 3.60 (s, 4H), 3.50(d, J = 6.1 Hz, 4H), 2.67 – 2.51 (m, 8H), 2.43 – 2.28 (m, 6H), 2.14 (dt, J =14.9, 7.8 Hz, 2H), 1.88 – 1.69 (m, 4H), 1.60 – 1.46 (m, 16H), 1.40 – 1.22 (m,60H), 1.12 (dd, J = 12.5, 7.0 Hz, 48H), 0.96 – 0.71 (m, 12H).

[0044] Example 2 Preparation of film-forming aid:

[0045] S1: Under nitrogen protection, 400g xylene, 0.1mol dibromoneopentyl glycol, and 0.22mol linoleic acid were added to the reactor and stirred until well mixed. The temperature was raised to 100℃, and then 2g p-toluenesulfonic acid was added. After reacting for 9h (water generated during the reaction was removed using a water separator), the temperature was lowered to room temperature. Saturated sodium bicarbonate solution was slowly added to adjust the pH to neutral. The mixture was stirred thoroughly for 30min, allowed to stand and separate into layers, and the organic phase was transferred to a rotary evaporator. The mixture was rotary evaporated at 70℃ for 3h and then vacuum dried at 70℃ for 10h to obtain a two-arm long-chain double bond compound.

[0046] S2: Add 800 ml of anhydrous acetonitrile, 0.23 mol of triethylamine, and 0.1 mol of a two-arm long-chain double bond compound to the reactor, stir and mix well, then slowly add 100 ml of anhydrous acetonitrile solution containing 0.22 mol of dodecyl diethylene glycol ether dropwise over 30 min. After the addition is complete, heat to reflux and react for 10 h. Filter, wash three times with deionized water (100 ml each time), distill under reduced pressure at 60 °C for 3 h, and dry under vacuum at 70 °C for 8 h to obtain a four-arm long-chain double bond compound.

[0047] S3: Add 500 ml of dichloromethane, 0.1 mol of a four-armed long-chain double bond compound, and 5 g of strong acid cation exchange resin to the reactor. Add 0.42 mol of formic acid and 50 g of a 30 wt% H2O2 mixed solution dropwise over 30 min. Stir and mix well. React at room temperature for 7 h. Filter, cool to 0 °C, adjust the pH to neutral with saturated sodium bicarbonate solution, allow to stand for separation, collect the organic phase, wash with 200 ml of ice water, add 50 g of anhydrous sodium sulfate and dry for 30 min. Filter, distill under reduced pressure at 35 °C for 2 h, and purify by column chromatography using petroleum ether / ethyl acetate (petroleum ether / ethyl acetate (V:V) gradient elution from 10:1 to 3:1). Distill under reduced pressure at 35 °C for 4 h, and dry under vacuum at 50 °C for 10 h to obtain the four-armed epoxy compound.

[0048] S4: Add 600ml DMF, 0.1mol four-arm epoxy compound, 0.82mol isobutyric anhydride, and 10g strong acid cation exchange resin to the reactor, stir and mix well, heat to 120℃, react for 10h, cool to room temperature, filter, then pour into 1000ml ice water, stir, precipitate, centrifuge, collect the solid product, wash three times with deionized water (300ml each time), and vacuum dry at 50℃ for 12h to obtain the film-forming aid.

[0049] Example 3 Preparation of film-forming aid:

[0050] S1: Under nitrogen protection, 400g xylene, 0.1mol dibromoneopentyl glycol, and 0.23mol linoleic acid were added to the reactor and stirred until well mixed. The temperature was raised to 90℃, and then 2g p-toluenesulfonic acid was added. After reacting for 10h (water generated during the reaction was removed using a water separator), the temperature was lowered to room temperature. Saturated sodium bicarbonate solution was slowly added to adjust the pH to neutral. The mixture was stirred thoroughly for 30min, allowed to stand and separate into layers, and the organic phase was transferred to a rotary evaporator. The mixture was rotary evaporated at 70℃ for 3h and then vacuum dried at 70℃ for 10h to obtain a two-arm long-chain double bond compound.

[0051] S2: Add 800 ml of anhydrous acetonitrile, 0.23 mol of triethylamine, and 0.1 mol of a two-arm long-chain double bond compound to the reactor, stir and mix well, then slowly add 100 ml of anhydrous acetonitrile solution containing 0.23 mol of dodecyl diethylene glycol ether dropwise over 30 min. After the addition is complete, heat to reflux and react for 11 h. Filter, wash three times with deionized water (100 ml each time), distill under reduced pressure at 60 °C for 3 h, and dry under vacuum at 70 °C for 8 h to obtain a four-arm long-chain double bond compound.

[0052] S3: Add 500 ml of dichloromethane, 0.1 mol of a four-armed long-chain double bond compound, and 5 g of strong acid cation exchange resin to the reactor. Add 0.43 mol of formic acid and 50 g of a 30 wt% H2O2 mixed solution dropwise over 30 min. Stir and mix well. React at room temperature for 8 h. Filter, cool to 0 °C, adjust the pH to neutral with saturated sodium bicarbonate solution, allow to stand for separation, collect the organic phase, wash with 200 ml of ice water, add 50 g of anhydrous sodium sulfate and dry for 30 min. Filter, distill under reduced pressure at 35 °C for 2 h, and purify by column chromatography using petroleum ether / ethyl acetate (petroleum ether / ethyl acetate (V:V) gradient elution from 10:1 to 3:1). Distill under reduced pressure at 35 °C for 4 h, and dry under vacuum at 50 °C for 10 h to obtain the four-armed epoxy compound.

[0053] S4: Add 600ml DMF, 0.1mol four-arm epoxy compound, 0.83mol isobutyric anhydride, and 10g strong acid cation exchange resin to the reactor, stir and mix well, heat to 120℃, react for 10h, cool to room temperature, filter, then pour into 1000ml ice water, stir, precipitate, centrifuge, collect the solid product, wash three times with deionized water (300ml each time), and vacuum dry at 50℃ for 12h to obtain the film-forming aid.

[0054] Example 4: Preparation of anti-corrosion water-based coating:

[0055] (1) Weigh: waterborne epoxy resin: 800g, waterborne curing agent (waterborne epoxy curing agent): 200g, curing accelerator (2-ethyl-4-methylimidazolium): 10g, dispersant (sodium dodecyl sulfate): 10g, film-forming aid (prepared in Example 1): 20g, defoamer (TEGO® Airex 902W): 5g, anti-flash rust agent (THIF-3118 type anti-flash rust agent): 5g, deionized water: 600g;

[0056] (2) Mix waterborne epoxy resin, deionized water, dispersant, defoamer, 10g film-forming aid and anti-flash rust agent, stir at 1000rpm for 20min to mix evenly; then add waterborne curing agent, curing accelerator and the remaining film-forming aid, stir at 600rpm for 5min to mix evenly, and let stand at room temperature for 20min to mature to obtain anti-corrosion waterborne coating.

[0057] Example 5: Preparation of anti-corrosion water-based coating:

[0058] (1) Weigh: waterborne epoxy resin: 900g, waterborne curing agent (waterborne epoxy curing agent): 230g, curing accelerator (2,4,6-tris(dimethylaminomethyl)phenol): 20g, dispersant (sodium tripolyphosphate): 15g, film-forming aid (prepared in Example 2): 25g, defoamer (TEGO® Airex 902W): 8g, anti-flash rust agent (THIF-3118 type anti-flash rust agent): 8g, deionized water: 700g;

[0059] (2) Mix waterborne epoxy resin, deionized water, dispersant, defoamer, 10g film-forming aid and anti-flash rust agent, stir at 1000rpm for 20min to mix evenly; then add waterborne curing agent, curing accelerator and the remaining film-forming aid, stir at 600rpm for 5min to mix evenly, and let stand at room temperature for 20min to mature to obtain anti-corrosion waterborne coating.

[0060] Example 6: Preparation of Anti-corrosion Waterborne Coating

[0061] (1) Weigh: waterborne epoxy resin: 1000g, waterborne curing agent (waterborne epoxy curing agent): 250g, curing accelerator (2,4,6-tris(dimethylaminomethyl)phenol): 30g, dispersant (sodium tripolyphosphate): 20g, film-forming aid (prepared in Example 3): 30g, defoamer (TEGO® Airex 902W): 10g, anti-flash rust agent (THIF-3118 type anti-flash rust agent): 10g, deionized water: 800g;

[0062] (2) Mix waterborne epoxy resin, deionized water, dispersant, defoamer, 10g film-forming aid and anti-flash rust agent, stir at 1000rpm for 20min to mix evenly; then add waterborne curing agent, curing accelerator and the remaining film-forming aid, stir at 600rpm for 5min to mix evenly, and let stand at room temperature for 20min to mature to obtain anti-corrosion waterborne coating.

[0063] Comparative Example 1

[0064] The raw material composition and preparation method of the anti-corrosion water-based coating are basically the same as those in Example 5, except that the film-forming aid is replaced with an equal weight of film-forming aid prepared by the following method:

[0065] The preparation method of the film-forming aid is basically the same as that in Example 2, except that the dibromoneopentyl glycol in step S1 is replaced with an equimolar amount of tribromoneopentyl alcohol.

[0066] Comparative Example 2

[0067] The raw material composition and preparation method of the anti-corrosion water-based coating are basically the same as those in Example 5, except that the film-forming aid is replaced with an equal weight of film-forming aid prepared by the following method:

[0068] The preparation method of the film-forming aid is basically the same as that in Example 2, except that the linoleic acid in step S1 is replaced with an equimolar amount of oleic acid.

[0069] Comparative Example 3

[0070] The raw material composition and preparation method of the anti-corrosion water-based coating are basically the same as those in Example 5, except that the film-forming aid is replaced with an equal weight of film-forming aid prepared by the following method:

[0071] The preparation method of the film-forming aid is basically the same as that in Example 2, except that the dodecyl diethylene glycol ether in step S2 is replaced with an equimolar amount of dodecyl alcohol.

[0072] Comparative Example 4

[0073] The raw material composition and preparation method of the anti-corrosion water-based coating are basically the same as those in Example 5, except that the film-forming aid is replaced with an equal weight of film-forming aid prepared by the following method:

[0074] The preparation method of the film-forming aid is basically the same as that in Example 2, except that isobutyric anhydride in step S4 is replaced with an equimolar amount of acetic anhydride.

[0075] Comparative Example 5

[0076] The raw material composition and preparation method of the anti-corrosion water-based coating are basically the same as those in Example 5, except that the film-forming aid is replaced with an equal weight of film-forming aid prepared by the following method:

[0077] The preparation method of the film-forming aid is basically the same as that in Example 2, except that the dibromoneopentyl glycol in step S1 is replaced with an equimolar amount of 6-bromo-1-hexanol.

[0078] The waterborne curing agent used in the embodiments and comparative examples of this application is a waterborne epoxy curing agent, model TC-3870, produced by Bath Synthetic New Materials (Shenzhen) Co., Ltd.; the waterborne epoxy resin is EMEP-6801W waterborne epoxy resin (general type), produced by Jiangsu Oumod New Materials Co., Ltd.; the strong acid cation exchange resin is a polymer of divinylbenzene and sodium vinylbenzene sulfonate, brand name Amberlite® IMACHP1110 resin, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0079] The anti-corrosion waterborne coating prepared in this application was tested for leveling, salt spray resistance and adhesion. The test results are shown in Table 1.

[0080] Leveling test: A Leneta paper (15×20cm) was flattened and fixed onto the automatic coater. A line bar with a wet film thickness of 100μm was selected. 10ml of paint was placed at one end of the Leneta paper. Holding both ends of the line bar with both hands, the paint was applied in one pass at a speed of 10cm / s. After 5 minutes of application, the surface condition of the paint film was observed from the side under 45° incident light. The evaluation criteria are as follows:

[0081] Advantages: Brush marks disappear completely within 1 minute, leaving the surface as smooth as a mirror.

[0082] Good: Brush marks basically disappear within 2-3 minutes, and tiny traces are barely noticeable to the naked eye.

[0083] Medium: The brush marks are still faintly visible after 5 minutes, but they are very shallow.

[0084] Poor: Brush marks are always clearly visible, and defects such as "orange peel" and pinholes may even appear.

[0085] Sample preparation: First, the tinplate sample (120×50×0.2mm) was sanded using 800-grit sandpaper in one direction. After rotating the substrate 90°, sanding continued. The surface of the metal substrate was rinsed with ethanol to remove stains, then wiped with degreased cotton and cleaned with acetone. The sample was dried with a blower and finally rinsed three times with anhydrous ethanol and dried for later use. A coating was prepared on the treated tinplate sample using a wire-bar applicator. The tinplate sample was fixed on a horizontal table, and the water-based coating was evenly applied to the surface using a wire-bar applicator. The film thickness was 25μm. After coating, the sample was allowed to stand at room temperature until the coating surface was dry. Then, it was placed in an environment with room temperature and 50% relative humidity for 48 hours to dry completely. After two days of standing, testing was conducted.

[0086] Salt spray resistance test: The salt spray resistance test was carried out on the samples prepared by the anti-corrosion water-based coatings prepared by the examples and comparative examples in accordance with GB / T1771-2007 Determination of resistance to neutral salt spray of paints and varnishes. The maximum test time for each sample was 1000h (observed every 10h after 800h of test).

[0087] Adhesion Test: Referring to GB / T 9286-2021 "Cross-cut Test for Paint and Varnish Films", adhesion tests were conducted on samples prepared using the anti-corrosion water-based coatings obtained in the examples and comparative examples. A 5×5 grid pattern (6 horizontal lines, 6 vertical lines, 1mm spacing, penetrating to the substrate) was cut into the paint film using a single-edged cross-cutting tool. Debris was brushed away, and special pressure-sensitive adhesive tape was applied and quickly peeled off. The degree of paint film peeling off the grid areas was observed. Adhesion was graded from best to worst as 0-5, with 0 representing the best and 5 representing the worst.

[0088] Table 1 Performance Test Data of Anti-corrosion Waterborne Coatings

[0089]

[0090] Note: If the salt spray resistance test data is 1000, it means that no blistering, cracking, peeling, or chalking was observed in the coating at 1000h; if the data is in the form of AAA / BBB, it means that no blistering, cracking, peeling, or chalking was observed in the coating at AAAh, and blistering was observed starting at BBBh.

[0091] As can be seen from Table 1, the water-based coating prepared in this application has excellent corrosion resistance, adhesion and leveling properties.

[0092] The film-forming aid prepared in this invention has a four-arm structure, consisting of two long alkyl ether chains and two isobutyrate group segments. This four-arm structure effectively reduces the crosslinking density of the resin system during film formation, imparting good internal plasticizing effect and flexibility to the coating film, thereby significantly improving leveling and avoiding defects such as pinholes. The long alkyl ether chains contained in the film-forming aid have excellent flexibility and hydrophobicity. During film formation, the long alkyl ether chains can interact with the substrate (metal) surface through van der Waals forces and hydrophobic adsorption, penetrating deep into the micropores of the substrate, enhancing the chemical affinity of the coating film, and thus significantly improving adhesion. At the same time, the flexibility of the long alkyl ether chains helps to release the internal stress generated during curing, avoiding coating shrinkage or peeling caused by stress concentration, and enhancing the adhesion effect. In addition, the hydrophobic long alkyl ether chains form an effective physical barrier, hindering the penetration of water molecules and corrosive media, and improving salt spray resistance. The isobutyrate group in the film-forming aid has excellent hydrolytic stability. Its steric hindrance effect (from the two methyl groups at the α position) can effectively shield the ester group, making it difficult to hydrolyze in the aqueous system and ensuring the stability of the coating during storage and use. At the same time, the steric hindrance effect significantly enhances the hydrophobic shielding of the molecule, effectively blocking the penetration of corrosive media. In addition, the ester bond can also form strong hydrogen bonds with polar groups on the substrate surface or in the resin, enhancing the adhesion of the coating film to substrates such as metals.

[0093] The oleic acid used in Comparative Example 2 has only one double bond, which can only generate two isobutyrate groups in the end. Isobutyrate groups are strong hydrogen bond acceptors. The reduction in their number decreases the ability of the molecule to form hydrogen bonds with the substrate or resin, thus reducing the adhesion of the coating film.

[0094] The dodecyl alcohol used in Comparative Example 3 has only long alkyl chains. Although the hydrophobicity is enhanced, the chain segment flexibility and mobility are reduced, and there are no hydrogen bonding sites for ether bonds. This hydrophobic long chain will hinder the uniform distribution and orientation of molecules in the resin system, resulting in a decrease in leveling properties.

[0095] The acetic anhydride used in Comparative Example 4 generates straight-chain acetate groups. Its small molecular size and lack of branch shielding make the ester bonds more susceptible to water molecule attack, resulting in decreased hydrolysis resistance and corrosion resistance. Furthermore, its hydrophobicity is weak, and the steric hindrance around the hydrogen bond binding sites is small, resulting in weak forces and weakened adhesion.

[0096] The 6-bromo-1-hexanol used in Comparative Example 5 is a monofunctional linear molecule that can only generate a two-arm structure, which halves the number of isobutyrate groups. The reduction in hydrogen bonding sites directly weakens the interaction with the substrate, resulting in decreased adhesion. The reduced density of branched hydrophobic end groups weakens the shielding ability against corrosive media, leading to poorer corrosion resistance.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. An anticorrosive water-based paint characterized by, The raw materials include the following by weight: Waterborne epoxy resin: 80-100 parts, waterborne curing agent: 20-25 parts, curing accelerator: 1-3 parts, dispersant: 1-2 parts, film forming aid: 2-3 parts, defoaming agent: 0.5-1 part, anti-flash rust agent: 0.5-1 part, deionized water: 60-80 parts; The film forming aid is prepared by the following method: S1: linoleic acid reacts with dibromoneopentyl glycol to form a two-arm long-chain double bond compound, S2: the two-arm long-chain double bond compound reacts with dodecyl diethylene glycol ether to form a four-arm long-chain double bond compound, S3: the four-arm long-chain double bond compound reacts under the condition of formic acid and hydrogen peroxide to form a four-arm epoxy compound, S4: the four-arm epoxy compound reacts with isobutyric anhydride to form a film forming aid.

2. The anticorrosive water-based paint according to claim 1, characterized by In step S1, the molar ratio of the linoleic acid to the dibromoneopentyl glycol is (2.1-2.3):

1.

3. The anticorrosive water-based paint according to claim 1, characterized by In step S2, the molar ratio of the two-arm long-chain double bond compound to the dodecyl diethylene glycol ether is 1:(2.1-2.3).

4. The anticorrosive water-based paint according to claim 1, characterized by In step S3, the molar ratio of the four-arm long-chain double bond compound to the formic acid is 1:(4.1-4.3).

5. The anticorrosive water-based paint according to claim 1, characterized by In step S4, the molar ratio of the four-arm epoxy compound to the isobutyric anhydride is 1:(8.1-8.3).

6. The anticorrosive water-based paint according to claim 1, characterized by The waterborne curing agent is a waterborne epoxy curing agent.

7. The anticorrosive water-based paint according to claim 1, characterized by The curing accelerator is one of 2-ethyl-4-methylimidazole, 2,4,6-tris(dimethylaminomethyl)phenol.

8. The anticorrosive water-based paint according to claim 1, characterized by The defoaming agent is TEGO®Airex 902W.

9. The anticorrosive water-based paint according to claim 1, characterized by The anti-flash rust agent is THIF-3118 type anti-flash rust agent; the dispersant is one of sodium dodecyl sulfate, sodium tripolyphosphate.

10. A method for the preparation of the anticorrosive water-based paint according to any one of claims 1 to 9, characterized in that, The method includes the following steps: (1) weighing by weight parts: waterborne epoxy resin: 80-100 parts, waterborne curing agent: 20-25 parts, curing accelerator: 1-3 parts, dispersant: 1-2 parts, film forming aid: 2-3 parts, defoaming agent: 0.5-1 part, anti-flash rust agent: 0.5-1 part, deionized water: 60-80 parts; (2) mixing the waterborne epoxy resin, deionized water, dispersant, defoaming agent, 1 part of the film forming aid and the anti-flash rust agent, and stirring uniformly; then adding the waterborne curing agent, the curing accelerator and the remaining film forming aid, and stirring uniformly, and standing at room temperature to obtain the corrosion-resistant waterborne paint.

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