CN111334161A - A kind of flexible self-healing anti-corrosion coating for inner wall of seawater steel pipeline and preparation method thereof - Google Patents

Abstract

The invention relates to the field of corrosion prevention, in particular to a flexible self-repairing corrosion prevention matched coating for the inner wall of a seawater steel pipeline and a preparation method thereof. The matched coating consists of a primer and a finish; wherein, the priming paint comprises, by weight, 0.5-2% of epoxy microcapsule, 35-45% of pigment filler A, 10-20% of organic solvent A, 1-4.5% of auxiliary agent A, 20-30% of curing agent A and the balance of organic resin A; the finishing coat comprises, by weight, 1.5-4.5% of toughened modified resin, 40-45% of pigment and filler B, 10-15% of organic solvent B, 1-4.5% of auxiliary agent B, 15-20% of curing agent B and the balance organic resin B. Compared with other similar coatings, the coating has the advantages of good flexibility, peeling resistance, impact resistance, salt spray resistance and other anticorrosion performances after being cured into a film, simple process and low cost.

Description

A kind of flexible self-healing anti-corrosion coating for the inner wall of seawater steel pipeline and its preparation method

technical field

The invention relates to the field of anti-corrosion, in particular to a flexible self-repairing anti-corrosion matching coating for the inner wall of a seawater steel pipeline and a preparation method.

Background technique

Seawater steel pipes are located in a special environment and have high requirements for coating materials. Common coatings used in this environment have the disadvantages of low service life and frequent maintenance. The reason is that on the one hand, due to the harsh marine environment, the coating is prone to long-term erosion such as chloride ions, and bubbling and peeling; Cathodic protection produces interference from stray currents, and the coating is prone to large-area cathodic disbondment. Due to the difficulty in repairing the coating on the inner wall of the pipeline, it is necessary to develop a coating system that can self-repair, resist erosion and have cathodic disbondment resistance, which can improve the protective performance of the coating, prolong the repair period of the coating, and achieve long-term effects on the substrate. Corrosion protection is very important.

SUMMARY OF THE INVENTION

In view of the deficiencies of the existing coatings, the purpose of the present invention is to provide a flexible self-repairing anti-corrosion matching coating for the inner wall of a seawater steel pipeline and a preparation method.

In order to realize the purpose of the invention, the present invention adopts the technical scheme as follows:

A flexible self-repairing and anti-corrosion matching coating for the inner wall of a seawater steel pipeline, the matching coating is composed of a primer and a topcoat; wherein, the primer is based on the weight percentage of 0.5-2% of epoxy microcapsules, 0.5-2% of pigment Filler A 35-45%, organic solvent A 10-20%, auxiliary agent A1-4.5%, curing agent A 20-30%, the balance is organic resin A; the topcoat is based on weight percent, toughening modified resin 0.5-2%, pigment and filler B 40-45%, organic solvent B10-15%, auxiliary agent B1-4.5%, curing agent B15-20%, and the balance is organic resin B.

The organic resin A is an epoxy resin with a molecular weight of about 380-400; the pigment and filler A is one or more of zinc phosphate, aluminum powder, iron red, talc and white carbon black; the curing agent A is an amine type curing agent, such as polyamide type TL-285, modified amine curing agent 9593, etc.

The epoxy microcapsules have a core-shell structure; wherein, the core is an epoxy resin with a corrosion inhibitor added, and the shell layer is a urea-formaldehyde resin prepolymer; the corrosion inhibitor is a carboxylic acid and/or a carboxylic acid derivative. one or more. Wherein, the dosage ratio between the core and shell is 0.8-1.3:1; the addition amount of the corrosion inhibitor is 0.5%-1.0% of the mass of the epoxy microcapsule, and the molecular weight of the epoxy resin is 440-460.

The corrosion inhibitor is a carboxylic acid corrosion inhibitor, and its carboxyl terminal is connected to a functional group; the functional group is one or more of a carboxyl group, a phosphonic acid group, and a hydroxyl group; the main types of the corrosion inhibitor are: 2-Phosphate butane-1,2,4-tricarboxylic acid, dodecenyl-1-dioic acid, oleophthalosine, etc.

The epoxy microcapsules

1) Synthesis of urea-formaldehyde resin prepolymer: urea and formaldehyde solution are mixed, and the mass ratio is 1:2-1:1; the pH value of the above mixed solution is adjusted to 8-9, and the water bath is heated to 70-75° C. to be reacted Cool to room temperature after 1-2 hours.

2) Preparation of microcapsule core material: Mix epoxy resin with trimethylolpropane triglycidyl ether and corrosion inhibitor in a mass ratio of 4.5-5:1-1.5:0.1-0.2, and then emulsify and disperse for 10-15 minutes. lotion.

3) Synthesis of epoxy resin microcapsules: ionized water and sodium dodecylbenzenesulfonate are dissolved in deionized water, and after dissolving, step 2) is added to obtain the emulsion of the microcapsule core material and the above step 1) urea-formaldehyde resin prepolymer Mix with urea-formaldehyde resin curing accelerator at a ratio of 1-2:1-1:2, adjust the pH value of the system to 5-6, heat to 60-65°C, react for 3-4 hours, and filter the obtained microcapsules.

The toughening modified resin is an epoxy resin toughened and modified by polyurethane, and the toughening modified resin accounts for 3wt%-7wt% of the total amount of the topcoat.

Preparation of the toughened modified resin

1) Synthesis of polyurethane prepolymer: vacuum dehydration of polyether polyol (molecular weight of 800-2000) is lowered to 30-40°C under nitrogen protection, then hexamethylene diisocyanate is added, and under nitrogen protection The temperature of the system was raised to 80-85 °C, and the reaction was carried out for 3 h to obtain a prepolymer. Wherein, the mass ratio of polyether polyol and hexamethylene diisocyanate is 2-3:1-2.

2) Synthesis of polyurethane toughened epoxy resin: add epoxy resin with a molecular weight of about 380-400 to the above-reacted prepolymer, react at 80-85°C for 1-2h, and then add dibutyltin dilaurate , after continuing the reaction for 0.5-1h, vacuum degassing until no foam, cooling to 30-40 ℃ to obtain a toughened modified resin.

The organic resin B is an epoxy resin with a molecular weight of about 900-1100; the pigment and filler B is one or more of mica iron oxide, calcium carbonate, talc and titanium dioxide; the curing agent B is an amine curing agent , such as polyamide 650, polyetheramine T403 and D230, etc.

The auxiliary agent A is a leveling agent accounting for 0.5-1% of the quality of the primer, a defoamer accounting for 1-1.5% of the quality of the primer and a dispersant accounting for 1-2% of the quality of the primer;

The auxiliary agent B is a leveling agent that accounts for 0.5-1% of the quality of the topcoat, a defoaming agent that accounts for 1-1.5% of the mass of the topcoat, and a dispersant that accounts for 1-2% of the mass of the topcoat. agent;

The organic solvent A and the organic solvent B are methyl isobutyl ketone and xylene with a mass ratio of 2:1-1:2.

A preparation method of a flexible self-repairing anti-corrosion supporting coating for the inner wall of a seawater steel pipeline, the epoxy microcapsule primer coating is scraped on the metal surface, and then the topcoat of the toughening modified resin is coated The layer is blade-coated on the surface of the primer coating to form a flexible and modified topcoat; wherein, the thickness of the primer coating is ≥250 μm, and the thickness of the topcoat coating is ≥200 μm.

Preparation of the primer coating:

According to the above ratio, the epoxy microcapsules are added to the organic solvent A to be dispersed uniformly, and part of the organic resin A, the pigment and filler A, the dispersant and the defoamer are added to the dispersion in turn, and the dispersion is uniformly dispersed to obtain a dispersion for use;

Mixing the above-obtained dispersion with the remaining organic resin A, then adding a leveling agent, fully stirring, then adding a curing agent A, and drying to obtain a primer coating;

Preparation of the topcoat coating:

According to the above ratio, add the toughening modified resin to the organic solvent B to disperse evenly, add part of the organic resin B, pigment and filler B, dispersant and defoamer to the dispersion in turn, stir and disperse evenly to obtain a dispersion for use ;

Mix the dispersion obtained above with the remaining organic resin B, then add a thickener and a leveling agent, stir well, then add a curing agent B, and dry to obtain a topcoat.

The metal is water pipeline or chemical equipment.

The present invention has the advantages:

The coatings of the present invention comprise epoxy microcapsules, corrosion inhibitors, toughened modified epoxy resins and organic resins. The corrosion inhibitor uses epoxy microcapsules as the carrier, and is uniformly dispersed in the organic resin to form a film, which not only improves the corrosion resistance of the coating, but also improves the adhesion between the coating and the substrate. The toughening and toughening modified resin in the present invention forms a cross-linked network structure in the organic resin, improves the toughness and anti-scour performance of the coating, and reduces the damage probability of the coating. Compared with other similar coatings, the invention can prolong the damage period of the coating after curing into a film, and has anti-corrosion properties such as salt water penetration resistance, high adhesion, good flexibility, resistance to cathodic disbonding, simple process and low cost .

Description of drawings

Fig. 1 is the microstructure diagram of the epoxy microcapsule of the embodiment of the present invention;

Fig. 2 is the infrared spectrogram of the epoxy microcapsule of the embodiment of the present invention;

Fig. 3 provides the tensile properties comparison diagram of modified resin and unmodified resin for an embodiment of the present invention;

4 is a photo of the surface morphology of the composite coating provided by the embodiment of the present invention under salt spray conditions for 8 months;

5 is a photo of the surface morphology of the pure epoxy coating provided by the embodiment of the present invention under salt spray conditions for 8 months;

6 is a comparison diagram of the AC impedance spectrum of the composite coating provided by the embodiment of the present invention and the pure epoxy coating after 4 months of salt spray accelerated test;

Fig. 7 is the surface topography of the test piece after the composite coating provided by the embodiment of the present invention is immersed in a voltage of -1.5v, a temperature of 60°C, and 3.5% NaCl salt water for 60 days

Fig. 8 is the sample picture after the bending resistance test of the composite coating provided by the embodiment of the present invention

Fig. 9 is the sample picture after the impact resistance test of the composite coating provided by the embodiment of the present invention

Detailed ways

After extensive and in-depth research, the present invention obtains a flexible self-repairing and anti-corrosion matching coating for the inner wall of seawater steel pipelines. After the film is formed, it has both good peeling resistance and chloride ion permeation resistance, low cost, and provides a simple process for metal anticorrosion.

The primer of the invention is to uniformly disperse the epoxy microcapsules into the organic resin, and then solidify with a curing agent to form a film, and the topcoat is to uniformly disperse the resin and organic resin modified by flexibility and toughening, pigments, fillers and auxiliary agents, and then It can be cured with a curing agent to form a film, so that the coating has good anti-corrosion and anti-corrosion properties after damage. The epoxy microcapsule in the present invention is used as the carrier of the corrosion inhibitor, and the corrosion inhibitor is released after cross-linking in the resin, thereby improving the corrosion resistance of the substrate, and the toughening modified resin can improve the flexibility of the coating and reduce the The chance of the coating breaking due to external force. Compared with other similar coatings, the present invention has good flexibility, peeling resistance, impact resistance, salt spray resistance and other anti-corrosion properties after curing into a film, and the process is simple and the cost is low.

The substances provided by the present invention can be synthesized through commercially available raw materials or traditional chemical transformation methods. Among them, the leveling agent is BYK300, BYK310, BYK388, BYK331, RH-T1006, RH-T1006N, RH-T1023, RH-T1033, RH-T1033A, RH-T1045, RH-T1008, RH-T308, RH-T1057, One of RH-T1010, RH-T1245, defoamer is one of BYK051, BYK052, BYK053, BYK054, BYK056, BYK057, BYK065, BYK077, BYK066N, BYK065, BYK085, BYK0141, dispersant is BYK-P104S , BYK-163, BYK-110, BYK-161, BYK-164, BYK-111, BYK104S, DISPERBYK-160, DISPERBYK-161, DISPERBYK-162, the thickener is GARAMITE1958, GARAMITE 1210, HL- One of 150, HL-200, HL-139, BYK-R605.

Other aspects of the invention will be apparent to those skilled in the art from the disclosure herein.

The specific embodiments of the present invention will be further described below with reference to examples. It should be noted that the specific embodiments described herein are only for illustrating and explaining the present invention, and are not limited to the present invention.

Unless otherwise defined or indicated, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described can be used in the methods of the present invention.

The preparation of embodiment 1 epoxy microcapsules

1) synthesis of urea-formaldehyde resin prepolymer: urea and formaldehyde solution are mixed, and mass ratio is 1:2; wherein, described formaldehyde solution mass concentration is 37%, urea 25g, formaldehyde solution 50g; Adjust above-mentioned mixed solution with triethanolamine The pH value reaches 8-9, is added to the three-necked flask, the stirring speed is adjusted, the water bath is heated to 70 ° C, and the reaction is cooled to room temperature after 1 hour for use.

2) Preparation of microcapsule core material: Weigh 50 g of bisphenol A type E-44 epoxy resin, and 10 g of trimethylolpropane triglycidyl ether, and then add 1 g of 2-phosphate butane-1,2,4 - After mixing the trihydroxy acid (corrosion inhibitor), use a high-speed shear emulsifier to emulsify, and disperse for 10 minutes, which is a ready-to-use emulsion.

3) Synthesis of epoxy resin microcapsules: Weigh 100g of deionized water, add 2.4g of sodium dodecylbenzenesulfonate, dissolve and add to a 250ml three-necked flask, adjust the stirring speed, and add the above step 2) to obtain microcapsules 45g of the emulsion of the core material, after stirring for 5 minutes, add 45g of the urea-formaldehyde resin prepolymer in the above step 1) and 0.5g of resorcinol (urea-formaldehyde resin curing accelerator), add 2 drops of n-octanol, and stir at a constant speed for 5 minutes , use 0.4N dilute hydrochloric acid to adjust the pH value of the system to 5-6, heat to 60 ° C, react for 3 hours, filter to remove the unreacted urea-formaldehyde resin prepolymer and core material, wash the obtained product, dry at low temperature, Finally, the dried capsules are collected to obtain a microcapsule product (see Figures 1 and 2).

It can be seen from the SEM and TEM morphology images of the microcapsules in Fig. 1 that the SEM shows the spherical structure of the microcapsules, and the TEM shows the core-shell structure of the microcapsules. The infrared image of the microcapsules in Figure 2 shows that the microcapsules contain corrosion inhibitor groups, including hydroxyl groups, phosphoric acid groups, and carbonyl groups.

Example 2 Preparation of toughened modified resin

1) Synthesis of polyurethane prepolymer: 70 g of elastomer polyether polyol (molecular weight 800-2000) was dehydrated under vacuum at 120 °C for 1 h, then cooled to 40 °C under nitrogen protection, and then 12 g of hexamethylene was added. Diisocyanate, the temperature of the system was raised to 80°C under the protection of nitrogen, and the reaction was carried out for 3h to obtain a prepolymer.

2) Synthesis of polyurethane toughened epoxy resin: add 80 g of bisphenol A type E-51 epoxy resin to the above-reacted prepolymer, react at 80°C for 1 hour, and then add a few drops of dibutyltin dilaurate, After the reaction was continued for 0.5 h, vacuum degassing was started until no foaming, and the material was discharged after cooling to 40°C (see Figure 3).

The obtained toughened and modified resin and the unmodified epoxy resin B were tested for tensile properties, specifically, the tensile strength and displacement of the resin were measured with time. (see Figure 3);

From the comparison of the tensile properties of the toughened modified resin and the unmodified pure epoxy resin in Figure 3, it can be seen that the maximum tensile stress of the toughened modified resin is 2 times larger than that of the unmodified epoxy resin. , the tensile displacement of the coating can continue to increase, while for the unmodified epoxy resin, after reaching the maximum tensile stress, there is no longer any displacement, indicating that the flexibility of the modified resin is significantly enhanced.

Example 3 Preparation of 1# Epoxy Microcapsule Primer

(1) by weight percentage, take by weighing 2% of the epoxy microcapsules prepared above, add it to methyl isobutyl ketone and xylene with a mass ratio of 1:1, disperse it uniformly by a high-speed disperser, and then Take part of the organic resin A and add it to the above organic solvent containing epoxy microcapsules, continue to disperse evenly at high speed, and then add 1.1% defoamer BYK051 for primer, 1.2% dispersant BYK-P104S, 15% zinc phosphate, aluminum 8% of powder, 8% of talc, 5% of titanium dioxide and 2% of white carbon black are added into it to make the dispersion uniform, and the dispersion is ready for use.

(2) mixing the above-mentioned (1) obtained dispersion with the remaining primer organic resin A, then adding 1% of leveling agent BYK310, fully stirring to obtain an organic resin dispersion;

(3) Add the supporting curing agent of the primer resin to the organic resin dispersion in step (2) according to the volume ratio of 1:2.5, fully stir it evenly, and then dry it to obtain a flexible self-contained solution for the inner wall of the seawater steel pipeline. Primer for repairing anti-corrosion matching coatings.

The organic solvent is methyl isobutyl ketone and xylene, the mass ratio of the two is 1:1, the curing agent is polyamide 650; the epoxy resin is bisphenol A type E-51.

Example 4 Preparation of 1# toughening modified resin topcoat

(1) Weigh the toughening modified resin in a ratio of 1:10 by weight of the toughening modified resin and the organic resin B, and add it to the mixture of methyl isobutyl ketone and xylene with a mass ratio of 1:1 , the high-speed disperser will disperse it evenly, and then add part of the topcoat organic resin B to the above-mentioned dispersion liquid containing the toughening modified resin, continue to stir at high speed, and then add the 1% defoamer BYK051 for topcoat, 1.1% Dispersant BYK-P104S, mica iron oxide 9%, calcium carbonate 10%, talc 10% and titanium dioxide 13% were added to make it disperse evenly to obtain a dispersion for use;

(2) mixing the above-mentioned (1) obtained dispersion with the remaining topcoat organic resin B, then adding 0.6% leveling agent BYK310 and 1.5% thickening agent, fully stirring to obtain an organic resin dispersion;

(3) The volume ratio of the curing agent matched with the topcoat is 1:4 and added to the organic resin dispersion in step (1), fully stirred, and then dried to obtain a flexible self-contained adhesive for the inner wall of the seawater steel pipeline. Topcoat for repairing anti-corrosion matching coatings.

The curing agent is polyetheramine T403, and the organic resin B is E-20 type epoxy resin.

Example 5 Preparation of flexible self-healing anti-corrosion supporting coating for inner wall of 1# seawater steel pipeline

(1) Weigh 3.0g of epoxy microcapsule primer and evenly apply it to the surface of the treated steel test panel (150mm*70mm), adjust the oven temperature to 50°C, take it out after 2 hours, and put it at room temperature (23±2°C) , set aside after cooling.

(2) Weigh 2.8g of toughened modified resin topcoat and evenly apply it to the test panel for use in (1), put it at room temperature (23±2°C), and dry it to obtain the flexibility of the inner wall of the seawater steel pipe. Self-healing anti-corrosion supporting coating.

Example 6 Preparation of 2# Epoxy Microcapsule Primer

(1) by weight percentage, take by weighing 2% of the epoxy microcapsules prepared above, add it to methyl isobutyl ketone and xylene with a mass ratio of 1:1, disperse it uniformly by a high-speed disperser, and then Take part of the organic resin A and add it to the above-mentioned organic solvent containing epoxy microcapsules, continue to disperse evenly at high speed, and then add 1.1% defoamer BYK051 for primer, 1.2% dispersant BYK-P104S, 15% zinc phosphate, oxidized 10% of iron red, 6% of talc, 5% of titanium dioxide and 2% of white carbon black are added into it to make it evenly dispersed, and the dispersion is ready for use.

(2) mixing the above-mentioned (1) obtained dispersion with the remaining primer organic resin A, then adding 1% of leveling agent BYK310, fully stirring to obtain an organic resin dispersion;

(3) Add the supporting curing agent of the primer resin to the organic resin dispersion in step (2) according to the volume ratio of 1:2.5, fully stir it evenly, and then dry it to obtain a flexible self-contained solution for the inner wall of the seawater steel pipeline. Primer for repairing anti-corrosion matching coatings.

The organic solvent is methyl isobutyl ketone and xylene in a mass ratio of 1:1; the curing agent is polyamide 650; and the organic resin A is E-51 epoxy resin.

Example 7 Preparation of 2# toughening modified resin topcoat

(1) Weigh the toughening modified resin in a ratio of 1:10 by weight of the toughening modified resin and the organic resin B, and add it to a mixture of methyl isobutyl ketone and xylene with a mass ratio of 1:1 The medium and high-speed dispersing machine will disperse it evenly, then add part of the topcoat organic resin B to the above-mentioned dispersion liquid containing the toughening modified resin, continue to stir at high speed, and then add the topcoat 1% defoamer BYK051, 1.1 % Dispersant BYK-P104S, mica iron oxide 10%, heavy calcium 8%, light calcium 8% talc 6% and titanium dioxide 10% were added to make it disperse evenly, and the dispersion was ready for use;

(2) mixing the above-mentioned (1) obtained dispersion with the remaining topcoat organic resin B, then adding 0.6% leveling agent BYK310 and thickening agent 1.5% HL-150, fully stirring to obtain an organic resin dispersion;

(3) The volume ratio of the curing agent matched with the topcoat is 1:4 and added to the organic resin dispersion in step (1), fully stirred, and then dried to obtain a flexible self-contained adhesive for the inner wall of the seawater steel pipeline. Topcoat for repairing anti-corrosion matching coatings.

The curing agent is polyetheramine T403; the organic resin B is E-20 type epoxy resin.

Example 8 Preparation of flexible self-healing anti-corrosion supporting coating for inner wall of 2# seawater steel pipeline

(1) Weigh 4.0g of epoxy microcapsule primer and evenly apply it to the surface of the treated steel test plate (150mm*70mm), adjust the oven temperature to 50°C, take it out after 2 hours, and put it at room temperature (23±2°C) , set aside after cooling.

(2) Weigh 3.5g of toughened modified resin topcoat and evenly apply it to the test panel for use in (1), put it at room temperature (23±2°C), and dry it to obtain the flexibility of the inner wall of the seawater steel pipe. Self-healing anti-corrosion supporting coating.

Application example: Comparison of anti-corrosion effects of flexible self-healing anti-corrosion matching coatings for inner wall of seawater steel pipelines

(1) Salt spray resistance of the coating

The flexible self-healing anti-corrosion supporting coating and blank epoxy coating obtained in the above example for the inner wall of steel pipes were put into a salt spray box with a concentration of 5% for 8 months, taken out and dried at room temperature to take pictures (See Fig. 4, Fig. 5), it can be seen from Fig. 4 that the surface of the composite coating is smooth and clean, without rust spots, bubbling and peeling, and as can be seen from Fig. 5, there is a lot of rust on the surface of the blank epoxy coating, while the coating of the present invention has a lot of rust. No obvious bubbling and rusting occurred.

(2) Electrochemical impedance spectrum after salt spray test of flexible self-healing anti-corrosion supporting coating for inner wall of steel pipe

After 4 months of salt spray test in a salt spray test chamber, a dot with a diameter of 1 mm was artificially destroyed in the center of the test surface, and then the electrochemical impedance spectrum of the coating/metal system was tested. A P4000+ electrochemical workstation was used, a saturated calomel electrode with a Lukin capillary was used as a reference electrode, a platinum sheet electrode was used as a counter electrode, and the coating/carbon steel electrode of the present invention was used as a working electrode, and the open circuit potential was immersed in a simulated seawater solution After the (OCP) is stabilized, the EIS test is performed with a sine wave disturbance amplitude of 20mV and a frequency range of 100kHz-0.01Hz under OCP. The results are shown in Figure 6. It can be seen from FIG. 5 that the system impedance of the coating of the present invention is 2 times larger than that of the pure epoxy coating after being artificially destroyed after 4 months of salt spray test. It can be seen that the coating of the present invention has more excellent anti-corrosion ability than the pure epoxy coating.

(3) Cathodic disbondment resistance of flexible self-healing anti-corrosion supporting coatings for inner walls of steel pipes

After 50 days of salt water immersion experiments, the results of the cathodic disbondment test of the coated test panel of the present invention at a voltage of 1.5v are shown in FIG. 7 . The results show that there is no bubbling, peeling and rusting on the surface of the coating, indicating that the composite coating has good resistance to cathodic disbonding.

(4) The mechanical properties of the flexible self-healing anti-corrosion supporting coating for the inner wall of the 1# steel pipe, and the test results of the coating being bent under the shaft rod of Φ2mm, as shown in Figure 8, the results show that the coating of the present invention does not crack , indicating that it has excellent bending resistance and flexibility.

When a 1kg weight fell from a height of 50cm and impacted the surface of the coating, as shown in Figure 9, it can be seen that the coating is not damaged, cracked or peeled off, indicating that the coating of the present invention has excellent impact resistance.

It can be seen from the above-mentioned supporting coatings of the examples that after passing the salt spray test for 8 months, the coatings have no phenomena such as blistering, rusting, peeling, etc.; and from the bending resistance and impact resistance test results, the coating has excellent Mechanical properties, can resist the impact of seawater and sand on the inner wall of the pipeline.

Claims (10)

1. A flexible self-repairing anticorrosion matched coating for the inner wall of a seawater steel pipeline is characterized in that: the matched coating consists of a primer and a finish; wherein, the primer comprises, by weight, 0.5-2% of epoxy microcapsule, 35-45% of pigment filler A, 10-20% of organic solvent A, 1-4.5% of auxiliary agent A, 20-30% of curing agent A, and the balance of organic resin A; the finishing paint comprises, by weight, 0.5-2% of toughening modified resin, 78-45% of pigment filler B40, 10-15% of organic solvent B10, 1-4.5% of auxiliary agent B, 15-20% of curing agent B15, and the balance of organic resin B.

2. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 1, which is characterized in that: the organic resin A is epoxy resin with the molecular weight of about 380-400; the pigment filler A is one or more of zinc phosphate, aluminum powder, iron oxide red, talcum powder and white carbon black; the curing agent A is an amine curing agent.

3. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 1, which is characterized in that: the epoxy microcapsule is of a core-shell structure; wherein, the core is epoxy resin added with corrosion inhibitor, and the shell layer is urea-formaldehyde resin prepolymer; the corrosion inhibitor is one or more of carboxylic acids and/or carboxylic acid derivatives.

4. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 3, which is characterized in that: the carboxyl terminal of the carboxylic acid corrosion inhibitor is connected with a functional group; the functional group is one or more of carboxyl, phosphonic acid group and hydroxyl.

5. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 1, which is characterized in that: the toughening modified resin is epoxy resin toughened and modified by polyurethane, and the toughening modified resin accounts for 8-15 wt% of the organic resin B.

6. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 1, which is characterized in that: the organic resin B is epoxy resin with the molecular weight of about 900-; the pigment filler B is one or more of mica iron oxide, calcium carbonate, talcum powder and titanium dioxide; the curing agent B is an amine curing agent.

7. The flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline as claimed in claim 1, which is characterized in that: the auxiliary agent A is a leveling agent accounting for 0.5-1% of the mass of the primer, a defoaming agent accounting for 1-1.5% of the mass of the primer and a dispersing agent accounting for 1-2% of the mass of the primer;

the auxiliary agent B is a leveling agent accounting for 0.5-1% of the mass of the finish paint, a defoaming agent accounting for 1-1.5% of the mass of the primer paint, a dispersing agent accounting for 1-2% of the mass of the primer paint and a thickening agent accounting for 1-2% of the mass of the primer paint;

the organic solvent A and the organic solvent B are methyl isobutyl ketone and xylene in a mass ratio of 2:1-1: 2.

8. The preparation method of the flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline, which is disclosed by claim 1, is characterized by comprising the following steps of: the epoxy microcapsule primer coating is coated on the surface of metal by scraping, and then the surface coating of the toughening modified resin is coated on the surface of the primer coating by scraping to form a flexible modified surface coating; wherein the thickness of the primer coating is more than or equal to 250 mu m, and the thickness of the finish coating is more than or equal to 200 mu m.

9. The preparation method of the flexible self-repairing anticorrosion matched coating for the inner wall of the seawater steel pipeline, as recited in claim 8, is characterized in that:

preparing the primer coating:

adding the epoxy microcapsules into the organic solvent A according to the proportion, uniformly dispersing, sequentially adding part of the organic resin A, the pigment filler A, the dispersing agent and the defoaming agent into the dispersion liquid, uniformly stirring and dispersing to obtain a dispersion body for later use;

mixing the obtained dispersoid with the residual organic resin A, then adding the leveling agent, fully and uniformly stirring, then adding the curing agent A, and drying to obtain the primer coating;

the preparation of the finish coat comprises the following steps:

adding the toughening modified resin into the organic solvent B according to the proportion, uniformly dispersing, sequentially adding part of the organic resin B, the pigment and filler B, the dispersing agent and the defoaming agent into the dispersion liquid, uniformly stirring and dispersing to obtain a dispersion for later use;

and mixing the obtained dispersion with the rest of the organic resin B, then adding the thickening agent and the leveling agent, fully and uniformly stirring, then adding the curing agent B, and drying to obtain the finish coat.

10. The method of claim 9, wherein: the metal is a water pipeline or chemical equipment.

Images