Anticorrosive epoxy paint and method for its preparation

Abstract

The application discloses an anticorrosive epoxy paint and a preparation method thereof, and belongs to the technical field of chemical coating. The anticorrosive epoxy paint provided by the application comprises the following components in parts by weight: 40-50 parts of epoxy resin, 15-25 parts of anticorrosive hybrid filler, 10-14 parts of modified titanium white powder, 6-10 parts of barium sulfate, 2-5 parts of toughening agent and 40-45 parts of solvent. The epoxy paint is prepared by the following steps: mixing the epoxy resin and part of the solvent to obtain a resin solution, then adding the anticorrosive hybrid filler, the modified titanium white powder, the barium sulfate and the toughening agent into the resin solution, uniformly dispersing and grinding, finally adding the remaining solvent, and aging after mixing to obtain the epoxy paint. The anticorrosive epoxy paint provided by the application has scratch self-healing protection performance and a physical barrier, can generate a dense passivation film at a damaged paint film, prolongs a coating maintenance period, can prolong a medium penetration path, and thus reduces the penetration rate of water vapor and corrosive medium.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical coatings, and particularly relates to a kind of anticorrosive epoxy paint and a preparation method thereof. BACKGROUND

[0002] Epoxy paint is a kind of paint with epoxy resin as the main film-forming material, and its components include solvents, pigments and fillers, dispersants and defoamers, etc. It has good adhesion, chemical stability and mechanical strength, and is widely used in the fields of corrosion protection of ships, bridges, chemical equipment, etc. It can also be used for non-metallic surfaces and electrical appliances, pipelines and instruments used in hot and humid conditions.

[0003] However, with the increasingly harsh industrial environment (such as high humidity and high salt in the ocean, penetration of chemical medium, etc.), the traditional epoxy anticorrosive system gradually exposes technical bottlenecks. The traditional epoxy anticorrosive paint relies on the dense cross-linked structure of the resin to block the penetration of the medium, and the interface bonding force between the filler and the resin is weak, which is easy to form a penetration channel; some technologies use filler stacking to prevent corrosion from extending. Although the conventional flaky filler (mica, glass flake) can extend the medium path, it is limited by the planar geometry, and there are problems such as short medium penetration path, low directional arrangement degree, and large interlayer gap when stacking, resulting in high medium penetration rate and unable to meet the long-term protection requirements.

[0004] In view of the above, it is necessary to provide an epoxy paint with corrosion resistance. SUMMARY

[0005] Based on the deficiencies of the prior art, the purpose of the present application is to provide an anticorrosive epoxy paint and a preparation method thereof.

[0006] The first aspect of the present application provides an anticorrosive epoxy paint, which comprises the following components by weight fraction: epoxy resin 40-50 parts, anticorrosive hybrid filler 15-25 parts, modified titanium dioxide 10-14 parts, barium sulfate 6-10 parts, toughening agent 2-5 parts, and solvent 40-45 parts.

[0007] The anticorrosive hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps:

[0008] (1) The mica sheet is immersed in hydrofluoric acid and subjected to ultrasonic treatment, and then washed to neutral and dried to obtain acid-etched mica sheet;

[0009] (2) The acid-etched mica sheet and polyethyleneimine are stirred and mixed, and a phosphotungstic acid solution is added for adsorption reaction, and then filtered to obtain phosphotungstic acid loaded mica sheet;

[0010] (3) The phosphotungstic acid loaded mica sheet is modified with a silane coupling agent, and then dried to obtain mica@phosphotungstic acid.

[0011] It should be noted that the mica sheet is a layered silicate mineral, which is alternately composed of rigid layers of silicon aluminum oxide and interlayer gaps connected by weak ionic bonds. The present application forms grooves on the mica sheet by directional etching with hydrofluoric acid (HF). HF molecules preferentially penetrate the interlayer gap, break the ionic bond and attack the hydroxyl group, causing the weak bond between the layers to break and forming parallel grooves. Then, the grooves are modified with polyethyleneimine (PEI) cations. PEI is rich in protonated amine groups, which can reverse the negatively charged mica groove surface to strong positive charge after HF etching. The strong positive charge can generate electrostatic attraction with phosphotungstic acid anions, driving the phosphotungstic acid to be directionally absorbed in the grooves, forming a mica sheet loaded with phosphotungstic acid structure.

[0012] In some embodiments, the mass ratio of the mica sheet and the phosphotungstic acid solution is 2-4:1, and the mass concentration of the phosphotungstic acid solution is 40%.

[0013] In some embodiments, the mass concentration of hydrofluoric acid is 8-12%, and the amount of polyethyleneimine is 0.5-1.5% of the mass of the mica sheet.

[0014] In some embodiments, the silane coupling agent is selected from at least one of KH-560 and KH-550, and the amount of silane coupling agent is 5-7% of the mass of the mica sheet.

[0015] In some embodiments, in step (1), the ultrasonic treatment temperature is 35-45℃, and the ultrasonic treatment time is 25-35min; in step (2), the stirring temperature is 50-65℃, the stirring time is 50-70min, and the adsorption reaction time is 20-40min; in step (3), the drying temperature is 55-65℃.

[0016] In some embodiments, the toughening agent is selected from at least one of furfuryl alcohol resin, polyether sulfone resin, and carboxyl-terminated nitrile rubber.

[0017] The second aspect of the present application provides a preparation method of a corrosion-resistant epoxy paint, comprising the following steps:

[0018] S1: mixing epoxy resin and part of the solvent to obtain a resin solution;

[0019] S2: adding corrosion-resistant hybrid filler, modified titanium dioxide, barium sulfate, and toughening agent to the resin solution, uniformly dispersing, and then grinding;

[0020] S3: adding the remaining solvent to the S2 mixed system, mixing, and then aging to obtain the corrosion-resistant epoxy paint.

[0021] In some embodiments, the solvent is a mixture of toluene, xylene, and cyclohexanone in a mass ratio of 3-5:2-4:1-3.

[0022] In some embodiments, the modified titanium white powder is prepared by the following steps: dipping titanium white powder in a silane hydrolysis solution, washing and drying after dispersion to obtain the modified titanium white powder.

[0023] The silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in anhydrous ethanol, wherein the amount of anhydrous ethanol is 120 times that of KH-560.

[0024] In some embodiments, in S2, the dispersion is performed at 1400-1600 rpm for 35-45 min, and the grinding fineness is ≤20-30 μm; in S3, the maturation time is 15-30 min.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application creatively adds an anti-corrosion hybrid filler to the epoxy paint, the groove formed by etching mica with hydrofluoric acid can effectively extend the diffusion path of the corrosion medium, and reduce the permeability of water vapor and corrosion medium; the phosphotungstic acid is anchored in the groove through electrostatic adsorption, and can oxidize the erosive factor and actively eliminate the corrosion factor; when the paint film is damaged by corrosion, the phosphotungstic acid can form a dense passivation film (such as ) on the surface of the metal (such as Fe), seal the metal substrate and inhibit the anode dissolution, thereby improving the service life of the substrate and prolonging the maintenance period of the paint. The unmodified mica surface has hydrophilicity and is easy to settle and aggregate in organic solvents, so the mica phosphotungstic acid is modified by a silane coupling agent, and a chemical bridge is formed between the mica phosphotungstic acid and the epoxy resin to improve the adhesion. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in combination with specific embodiments.

[0028] Example 1

[0029] An anti-corrosion epoxy paint, by weight, comprises the following components: epoxy resin 45 parts, anti-corrosion hybrid filler 20 parts, modified titanium white powder 12 parts, barium sulfate 8 parts, furfuryl alcohol resin 3 parts, solvent 40 parts.

[0030] The anti-corrosion hybrid filler is mica phosphotungstic acid, which is prepared by the following steps:

[0031] (1) Take mica flakes and immerse them in 10% hydrofluoric acid, ultrasonic treat at 40℃ for 30 min, wash to neutral and dry to obtain acid-etched mica flakes;

[0032] (2) The acid-etched mica sheet and polyethyleneimine are mixed at 55℃ for 60 min, a 40% mass concentration phosphotungstic acid solution is added for 30 min adsorption reaction, and the phosphotungstic acid loaded mica sheet is obtained by filtration; wherein the amount of polyethyleneimine is 1% of the mass of the mica sheet, and the mass ratio of the mica sheet to the phosphotungstic acid solution is 3:1.

[0033] (3) The phosphotungstic acid loaded mica sheet is modified using silane coupling agent KH-560, and the mica@phosphotungstic acid is obtained by drying at 60℃; wherein the amount of silane coupling agent is 6% of the mass of the mica sheet.

[0034] The above anticorrosive epoxy paint is prepared by the following steps:

[0035] S1: The epoxy resin and 1 / 2 of the solvent (20 parts) are mixed to obtain a resin solution; wherein the solvent is a mixture of toluene, xylene and cyclohexanone in a mass ratio of 4:3:2;

[0036] S2: The anticorrosive hybrid filler, modified titanium dioxide, barium sulfate, and furfuryl alcohol resin are added to the resin solution and dispersed at 1500 rpm for 40 min, and then ground to a fineness of ≤25 μm after uniform dispersion; wherein the modified titanium dioxide is obtained by immersing titanium dioxide in a silane hydrolysis solution, and then washed and dried after dispersion; the silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in 120 times of anhydrous ethanol;

[0037] S3: The remaining 1 / 2 of the solvent (20 parts) is added to the S2 mixed system, and the anticorrosive epoxy paint is obtained after mixing and aging for 25 min.

[0038] Example 2

[0039] An anticorrosive epoxy paint, by weight, comprises the following components: epoxy resin 50 parts, anticorrosive hybrid filler 25 parts, modified titanium dioxide 14 parts, barium sulfate 10 parts, polyether sulfone resin 5 parts, and solvent 45 parts;

[0040] The anticorrosive hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps:

[0041] (1) The mica sheet is immersed in a 12% mass concentration hydrofluoric acid and ultrasonically treated at 45℃ for 25 min, washed to neutral, and then dried to obtain an acid-etched mica sheet;

[0042] (2) The acid-etched mica sheet and polyethyleneimine are mixed at 65℃ for 50 min, a 40% mass concentration phosphotungstic acid solution is added for 40 min adsorption reaction, and the phosphotungstic acid loaded mica sheet is obtained by filtration; wherein the amount of polyethyleneimine is 1.5% of the mass of the mica sheet, and the mass ratio of the mica sheet to the phosphotungstic acid solution is 4:1;

[0043] (3) The mica@phosphotungstic acid is obtained by modifying the phosphotungstic acid loaded mica sheet with silane coupling agent KH-550 and drying at 65℃; wherein the amount of silane coupling agent is 7% of the mica sheet.

[0044] The above anticorrosive epoxy paint is prepared by the following steps:

[0045] S1: Mix epoxy resin and 2 / 3 of solvent (30 parts) to obtain a resin solution; wherein the solvent is a mixture of toluene, xylene and cyclohexanone with a mass ratio of 5:4:3;

[0046] S2: Add anticorrosive hybrid filler, modified titanium dioxide, barium sulfate and polyether sulfone resin to the resin solution, disperse at 1600 rpm for 35 min, and grind to a fineness of ≤30 μm after uniform dispersion; wherein the modified titanium dioxide is obtained by immersing titanium dioxide in a silane hydrolysis solution, washing and drying after dispersion, and the silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in 120 times of anhydrous ethanol;

[0047] S3: Add the remaining 1 / 3 of the solvent (15 parts) to the S2 mixed system, mix and mature for 30 min to obtain the anticorrosive epoxy paint.

[0048] Example 3

[0049] An anticorrosive epoxy paint, by weight parts, includes the following components: epoxy resin 40 parts, anticorrosive hybrid filler 15 parts, modified titanium dioxide 10 parts, barium sulfate 6 parts, carboxyl-terminated nitrile rubber 2 parts, and solvent 45 parts;

[0050] The anticorrosive hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps:

[0051] (1) Take the mica sheet and immerse it in 8% hydrofluoric acid at 35℃ for 35 min of ultrasonic treatment, wash to neutral and dry to obtain acid-etched mica sheet;

[0052] (2) Mix the acid-etched mica sheet and polyethyleneimine at 50℃ for 70 min, add 40% phosphotungstic acid solution for 20 min of adsorption reaction, and filter to obtain phosphotungstic acid loaded mica sheet; wherein the amount of polyethyleneimine is 0.5% of the mass of the mica sheet, and the mass ratio of mica sheet to phosphotungstic acid solution is 2:1;

[0053] (3) The mica@phosphotungstic acid is obtained by modifying the phosphotungstic acid loaded mica sheet with silane coupling agent KH-560 and drying at 55℃; wherein the amount of silane coupling agent is 5% of the mica sheet.

[0054] The above anticorrosive epoxy paint is prepared by the following steps:

[0055] S1: mixing epoxy resin and 1 / 3 of solvent (15 parts) to obtain a resin solution; wherein the solvent is a mixture of toluene, xylene and cyclohexanone in a mass ratio of 3:2:1;

[0056] S2: adding anticorrosive hybrid filler, modified titanium dioxide, barium sulfate and carboxyl-terminated nitrile rubber to the resin solution, dispersing for 45 min at 1400 rpm, and grinding to a fineness of ≤20 μm after uniform dispersion; wherein the modified titanium dioxide is obtained by immersing titanium dioxide in a silane hydrolysis solution, and the silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in 120 times of anhydrous ethanol;

[0057] S3: adding the remaining 2 / 3 of the solvent (30 parts) to the S2 mixed system, mixing, and aging for 15 min to obtain the anticorrosive epoxy paint.

[0058] Example 4

[0059] An anticorrosive epoxy paint, comprising the following components in parts by weight: epoxy resin 42 parts, anticorrosive hybrid filler 18 parts, modified titanium dioxide 11 parts, barium sulfate 7 parts, furfuryl alcohol resin 3 parts, and solvent 42 parts;

[0060] The anticorrosive hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps:

[0061] (1) taking mica flakes, immersing them in 9% hydrofluoric acid, and ultrasonically treating them at 40℃ for 30 min, washing to neutral, and drying to obtain acid-etched mica flakes;

[0062] (2) mixing the acid-etched mica flakes and polyethyleneimine at 55℃ for 60 min, adding a 40% phosphotungstic acid solution for an adsorption reaction for 25 min, and filtering to obtain phosphotungstic acid-loaded mica flakes; wherein the amount of polyethyleneimine is 1% of the mass of the mica flakes, and the mass ratio of the mica flakes to the phosphotungstic acid solution is 3:1;

[0063] (3) modifying the phosphotungstic acid-loaded mica flakes with silane coupling agent KH-560, and drying at 60℃ to obtain mica@phosphotungstic acid; wherein the amount of silane coupling agent is 6% of the mass of the mica flakes.

[0064] The above anticorrosive epoxy paint is prepared by the following steps:

[0065] S1: mixing epoxy resin and 1 / 2 of solvent (21 parts) to obtain a resin solution; wherein the solvent is a mixture of toluene, xylene and cyclohexanone in a mass ratio of 5:2:3;

[0066] S2: Add the anticorrosive hybrid filler, modified titanium dioxide, barium sulfate, and furfuryl alcohol resin to the resin solution, and disperse at 1500 rpm for 40 min. After uniform dispersion, grind to a fineness of ≤25 μm. The modified titanium dioxide is obtained by immersing titanium dioxide in a silane hydrolysis solution, and then washing and drying after dispersion. The silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in 120 times anhydrous ethanol;

[0067] S3: Add the remaining 1 / 2 of the solvent (21 parts) to the S2 mixed system, mix, and then mature for 25 min to obtain the anticorrosive epoxy paint.

[0068] Example 5

[0069] An anticorrosive epoxy paint, by weight fraction, includes the following components: epoxy resin 48 parts, anticorrosive hybrid filler 23 parts, modified titanium dioxide 13 parts, barium sulfate 9 parts, polyether sulfone resin 4 parts, and solvent 44 parts.

[0070] The anticorrosive hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps:

[0071] (1) Take mica flakes and immerse them in a 11% mass concentration hydrofluoric acid solution, and ultrasonically treat at 40°C for 30 min. After washing to neutral, dry to obtain acid-etched mica flakes;

[0072] (2) Mix the acid-etched mica flakes and polyethyleneimine at 60°C for 65 min, and then add a 40% mass concentration phosphotungstic acid solution for an adsorption reaction of 30 min. Filter to obtain phosphotungstic acid-loaded mica flakes. The amount of polyethyleneimine is 1% of the mass of the mica flakes, and the mass ratio of mica flakes to phosphotungstic acid solution is 3:1;

[0073] (3) Modify the phosphotungstic acid-loaded mica flakes using silane coupling agent KH-550, and dry at 60°C to obtain mica@phosphotungstic acid. The amount of silane coupling agent is 6% of the mass of the mica flakes.

[0074] The above anticorrosive epoxy paint is prepared by the following steps:

[0075] S1: Mix the epoxy resin and 1 / 2 of the solvent (22 parts) to obtain a resin solution. The solvent is a mixture of toluene, xylene, and cyclohexanone in a mass ratio of 3:4:1;

[0076] S2: Add the anticorrosive hybrid filler, modified titanium dioxide, barium sulfate, and polyether sulfone resin to the resin solution, and disperse at 1450 rpm for 40 min. After uniform dispersion, grind to a fineness of ≤25 μm. The modified titanium dioxide is obtained by immersing titanium dioxide in a silane hydrolysis solution, and then washing and drying after dispersion. The silane hydrolysis solution is obtained by dissolving silane coupling agent KH-560 in 120 times anhydrous ethanol;

[0077] S3: add the remaining 1 / 2 of the solvent (22 parts) to the mixture of S2, and after mixing, let it mature for 25 minutes to obtain the anticorrosive epoxy paint.

[0078] Comparative Example 1

[0079] The example 1 is basically the same, the only difference is that the step (1) in the preparation of the anticorrosive hybrid filler is omitted, that is, the acid-etched mica sheet is replaced by a conventional mica sheet.

[0080] Comparative Example 2

[0081] The example 1 is basically the same, the only difference is that the phosphotungstic acid is replaced by the same amount of phosphoric acid.

[0082] Comparative Example 3

[0083] The example 1 is basically the same, the only difference is that the mica sheet is replaced by the same amount of glass flake.

[0084] In order to prove that the anticorrosive epoxy paint provided by the present application has excellent corrosion resistance, the epoxy paint prepared in examples 1-5 and comparative examples 1-3 is added with a curing agent and coated on a standard carbon steel plate with a dry film thickness of 120±5μm. The performance test of the epoxy paint and the coating film sample plate formed thereby is carried out, and the data is shown in Table 1.

[0085] Table 1

[0086]

[0087] As can be seen from Table 1, the anticorrosive epoxy paint provided by the examples of the present application has excellent corrosion resistance, and is superior to the comparative examples in all aspects. Comparative example 1 loses the physical barrier, the mica sheet lacks the groove structure, resulting in accelerated corrosion rate; comparative example 2 replaces phosphotungstic acid with phosphoric acid, loses the chlorine removal ability, and results in fast rust expansion speed; comparative example 3 replaces the mica sheet with the non-crystalline glass flake, resulting in micro-cracks on the surface instead of directional grooves, leading to uneven loading of phosphotungstic acid and easy occurrence of local corrosion.

[0088] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. An anti-corrosion epoxy paint, characterized in that, By weight, it includes the following components: 40-50 parts epoxy resin, 15-25 parts anti-corrosion hybrid filler, 10-14 parts modified titanium dioxide, 6-10 parts barium sulfate, 2-5 parts toughening agent, and 40-45 parts solvent. The corrosion-resistant hybrid filler is mica@phosphotungstic acid, which is prepared by the following steps: (1) Mica sheets were immersed in hydrofluoric acid and subjected to ultrasonic treatment. After washing until neutral, they were dried to obtain acid-etched mica sheets. (2) The acid-etched mica sheet and polyethyleneimine were stirred and mixed, and phosphotungstic acid solution was added to carry out the adsorption reaction. The mixture was then filtered to obtain phosphotungstic acid-loaded mica sheet. (3) Modify the phosphotungstic acid-supported mica sheet using a silane coupling agent, and obtain the mica@phosphotungstic acid after drying; The mass ratio of the mica sheet to the phosphotungstic acid solution is 2-4:1, and the mass concentration of the phosphotungstic acid solution is 40%. In step (1), the ultrasonic treatment temperature is 35-45℃ and the ultrasonic time is 25-35min; in step (2), the stirring temperature is 50-65℃ and the stirring time is 50-70min, and the adsorption reaction time is 20-40min; in step (3), the drying temperature is 55-65℃.

2. The anti-corrosion epoxy paint according to claim 1, characterized in that, The hydrofluoric acid has a mass concentration of 8-12%; the amount of polyethyleneimine used is 0.5-1.5% of the mass of the mica sheet.

3. The anti-corrosion epoxy paint according to claim 1, characterized in that, The silane coupling agent is selected from at least one of KH-560 and KH-550, and the amount of silane coupling agent used is 5-7% of the mass of the mica sheet.

4. The anti-corrosion epoxy paint according to claim 1, characterized in that, The toughening agent is selected from at least one of furfuryl alcohol resin, polyethersulfone resin, and carboxyl-terminated nitrile butadiene rubber.

5. A method for preparing the anti-corrosion epoxy paint according to any one of claims 1-4, characterized in that, Includes the following steps: S1: Mix epoxy resin and a portion of solvent to obtain a resin solution; S2: Add anti-corrosion hybrid filler, modified titanium dioxide, barium sulfate, and toughening agent to the resin solution, disperse evenly, and then grind. S3: Add the remaining solvent to the S2 mixture system, mix and mature to obtain the anti-corrosion epoxy paint.

6. The method for preparing the anti-corrosion epoxy paint according to claim 5, characterized in that, The solvent is a mixture of toluene, xylene and cyclohexanone in a mass ratio of 3-5:2-4:1-3.

7. The method for preparing the anti-corrosion epoxy paint according to claim 5, characterized in that, The modified titanium dioxide is prepared by the following steps: titanium dioxide is immersed in silane hydrolysate, dispersed, washed and dried to obtain modified titanium dioxide.

8. The method for preparing the anti-corrosion epoxy paint according to claim 5, characterized in that, In S2, the dispersion is carried out at 1400-1600 rpm for 35-45 min, and the grinding fineness is ≤20-30 μm; in S3, the aging time is 15-30 min.

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