CN116948496A - A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating and its preparation method - Google Patents

Abstract

The invention discloses a polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, which includes component A and component B. The mass ratio of component A to component B is 5:(0.7 ~1.3); the A component includes: 30-47 parts of epoxy resin, 10-25 parts of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 3-10 parts of talc powder, 5-12 parts of barium sulfate , 2 to 11 parts of titanium dioxide, 1 to 2 parts of dispersant, 1 to 2 parts of defoaming agent, 1 to 5 parts of emulsifier, 1 to 4 parts of silane coupling agent, 1 to 6 parts of film-forming aid, leveling 1 to 3 parts of agent, 3 to 10 parts of other additives, and 3 to 11 parts of water; the B component includes: 90 to 98 parts of epoxy resin curing agent, 1 to 5 parts of dispersant, and 1 to 5 parts of defoaming agent share. The preparation method of the anti-corrosion coating is as follows: mix component A and component B according to the proportion and stir evenly. The invention can achieve the purpose of green and environmental protection, and at the same time enhance the mechanical properties and chemical corrosion resistance of the epoxy resin.

Description

A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating and preparation method thereof

Technical field

The invention belongs to the technical field of anticorrosive coatings, and specifically relates to a polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anticorrosive coating and a preparation method thereof.

Background technique

Epoxy resin anticorrosive coatings have been widely used in the field of marine corrosion research due to their superior corrosion resistance, mechanical properties and strong adhesion. However, a simple epoxy resin coating has limited physical shielding capabilities, insufficient chemical corrosion resistance, single corrosion resistance, and insufficient coating hardness when faced with complex environments, so it is difficult to meet actual needs. It can be seen that it is of great significance to develop an epoxy resin anti-corrosion coating with better performance. The introduction of two-dimensional materials into polymer resins is considered an effective strategy to improve the corrosion resistance of coated samples. At present, epoxy resin anti-corrosion coatings mainly include water-based epoxy resin anti-corrosion coatings and solvent-based epoxy resin anti-corrosion coatings. However, solvent-based epoxy resin anti-corrosion coatings are more expensive and can easily cause environmental pollution and harm human health. With the improvement of people's environmental awareness, green and environmentally friendly water-based epoxy resin anti-corrosion coatings will become the trend of future industry development.

Polyaniline is a conductive polymer material. Its excellent chemical corrosion resistance and electrical conductivity make it an ideal material for improved epoxy resin anti-corrosion coatings. First, anti-corrosion coatings containing polyaniline can provide a mechanical shielding effect on metal base materials. Secondly, polyaniline has redox properties, which can promote the formation of a dense metal oxide layer at the interface between the coating and the metal substrate, thereby putting the metal in a passivated state, slowing down the corrosion rate of the metal, and effectively preventing corrosion phenomena. occur. Polyaniline also has the advantages of good stability, non-toxic, environmentally friendly, scratch-resistant, and pitting-resistant. However, polyaniline as an anti-rust pigment also has its shortcomings, namely, low solubility, poor processability, and difficulty in dispersing and dissolving in aqueous media.

As an anti-rust pigment, zinc phosphate can react with the metal surface to form a dense phosphating film, thereby preventing rust. In addition, it can react with carboxyl and hydroxyl groups in the base material and certain ions in the corrosive environment to form a protective film and play a corrosion inhibition role. Although zinc phosphate is a commonly used anti-rust pigment, it also has the disadvantages of insufficient anti-rust activity and slow formation of an effective protective film.

The excellent anti-rust ability of aluminum tripolyphosphate is mainly due to the anti-rust group (P ₃ O ₁₀ ^5- ) released by it. This group has strong coordination ability and activity and can form a dense structure with metal ions. Passivation film, thus effectively inhibiting metal corrosion. The pyrophosphate formed after the depolymerization of aluminum tripolyphosphate can be converted into orthophosphoric acid and react with the surface of the substrate again to form a stronger phosphating film, thus achieving "double rust prevention". In addition, aluminum tripolyphosphate has excellent storage stability and weather resistance. Aluminum tripolyphosphate is a solid inorganic acid. When used in coatings, attention must be paid to its compatibility with other raw materials to avoid adverse reactions that may affect the anti-corrosion properties of the coating. In order to overcome this problem, aluminum polyphosphate usually needs to be modified or pigmented to improve its stability and anti-corrosion properties in coatings.

The invention patent "A lignosulfonic acid/polyaniline/poly(3,4-ethylenedioxythiophene) composite antistatic coating and its preparation and application", publication number: CN112266699A, discloses a lignosulfonic acid/poly(3,4-ethylenedioxythiophene) composite antistatic coating and its preparation and application. Preparation method of aniline/poly(3,4-ethylenedioxythiophene) composite antistatic coating. In this invention, sodium lignosulfonate is first dissolved in aqueous hydrochloric acid solution, aniline and ammonium persulfate are added to react to obtain a lignosulfonic acid/polyaniline nanocomposite, and then the lignosulfonic acid/polyaniline nanocomposite is reacted with 3,4 Ammonium persulfate is added to the mixture of -ethylenedioxythiophene to react to obtain a lignosulfonic acid/polyaniline/poly(3,4-ethylenedioxythiophene) composite, and finally the lignosulfonic acid/polyaniline/poly(3 , 4-ethylenedioxythiophene), epoxy resin and epoxy resin curing agent are mixed evenly in the solvent to obtain an antistatic coating. The composite antistatic coating obtained by this method is low in cost, easy to use, and has good antistatic effect. However, its solvent uses organic solvents such as acetone, tetrahydrofuran, and xylene, which causes greater pollution to the ecological environment and harm to construction workers, and The anti-corrosion effect is not obvious, which limits its application in industry.

The invention patent "A ship bottom anti-corrosion coating and its preparation method", publication number: CN109517484A, discloses a ship bottom anti-corrosion coating composed of two components A and B and its preparation method. Among them, Group A is composed of water-based epoxy resin and deionized water, and Group B is composed of epoxy curing agent, polyaniline, furfural resin, isocyanate, zinc phosphate, diacetone alcohol and graphite powder. The coating has excellent acid resistance, water resistance, and salt spray resistance, and can meet the needs of the bottom layer of the ship. However, this invention fails to effectively solve the problems of poor adhesion and poor dispersion of polyaniline components, and fails to fully utilize the anti-corrosion ability of polyaniline.

None of the above invention patents can give full play to the anti-corrosion properties of polyaniline. In order to achieve better coating protection effects and considering the respective advantages and disadvantages of polyaniline, zinc phosphate and aluminum tripolyphosphate, zinc phosphate and aluminum tripolyphosphate can be used. Polyaniline is surface-polymerized to form a polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, which is introduced into the epoxy resin system to form a good synergistic protective effect and obtain a polyaniline-zinc phosphate that is green, environmentally friendly, and has excellent corrosion resistance. -Aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating further optimizes anti-corrosion performance, processing performance and dispersion performance.

Contents of the invention

In view of the above problems, the present invention provides a polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, which can achieve the purpose of green and environmental protection while enhancing the mechanical properties and chemical corrosion resistance of the epoxy resin.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating includes component A and component B. The mass ratio of component A to component B is 5: (0.7~1.3);

The A component includes: 30 to 47 parts of epoxy resin, 10 to 25 parts of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 3 to 10 parts of talc powder, 5 to 12 parts of barium sulfate, and 2 parts of titanium dioxide. ~11 parts, dispersant 1-2 parts, defoaming agent 1-2 parts, emulsifier 1-5 parts, silane coupling agent 1-4 parts, film-forming aid 1-6 parts, leveling agent 1-3 parts parts, 3 to 10 parts of other additives, 3 to 11 parts of water;

The B component includes: 90 to 98 parts of epoxy resin curing agent, 1 to 5 parts of dispersant, and 1 to 5 parts of defoaming agent.

Preferably, the epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, or glycidyl amine type epoxy resin with an epoxy value of 41 to 54. one or more of them.

Preferably, the dispersant is polyacrylate sodium salt solution, polycarboxylic acid sodium salt solution, modified styrene maleic acid copolymer solution, modified polyether solution, Dow 731A, BYK-155, Bi One or more of BYK-190 and BYK-192.

Preferably, the defoaming agent is concentrated silicone, polyethersiloxane copolymer emulsion, silicone polymer emulsion, Dow Corning AFE-3168, TEGO-8030, TEGO-810, BYK-A530 one or more of them.

Preferably, the emulsifier is one or more of modified polyurethane, polyoxyethylene octylphenol ether-10, Dow RM-12W, and Dow RM-8W.

Preferably, the silane coupling agent is 3-glycidoxypropyltrimethoxysilane (KH-560), 3-(2,3-epoxypropyloxy)propyltriethoxysilane (KH- 561), one or more of 3-mercaptopropyltriethoxysilane (KH-580), 3-aminopropyltriethoxysilane (KH-550).

Preferably, the film-forming assistant is one or more of dodecanol ester, cetyl alcohol ester, propylene glycol phenyl ether, and propylene glycol butyl ether.

Preferably, the leveling agent is polyether modified polydimethylsiloxane, fluorocarbon modified polyacrylate, BYK-331, BYK-333, BYK-378, BASF EFKA FL One or more of 3772.

Preferably, the other auxiliaries are one or more of iron red, manganese violet, iron blue, cobalt yellow, iron yellow, carbon black, manganese black, cobalt green, chrome green, and zinc white.

Preferably, the epoxy resin curing agent is one of polyamide, phenolic amine, and modified polyamide.

Preferably, the preparation method of component A is: combining epoxy resin, dispersant, defoaming agent, emulsifier, water, polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, talc powder, barium sulfate, titanium White powder, silane coupling agent, film-forming additive, leveling agent, and other additives are added to a high-speed dispersing sand mill under low-speed stirring, followed by high-speed dispersing sand milling for 2 to 8 hours, and sieved to obtain component A.

Preferably, the preparation method of component B is as follows: add the epoxy resin curing agent, dispersant, and defoaming agent to a high-speed dispersing sand mill under low-speed stirring, followed by high-speed dispersing sand milling for 1 to 3 hours, and sieving. Component B is obtained.

Preferably, the preparation method of the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is as follows:

Step 1: Add water, zinc phosphate, and aluminum tripolyphosphate into a sand mill and grind thoroughly for 1 to 4 hours. After filtering, drying, and pulverizing, the mixture powder is obtained;

Step 2: Add aniline and the mixture powder in step 1 to the water and stir thoroughly. Add a pH adjuster to adjust the pH value to 1.5~3.5 and control the temperature to 2~10°C.

Step 3: Prepare the oxidant solution, add it dropwise to the dispersion in step 2, fully react for 10 to 24 hours, and obtain the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material after separation, washing, and drying.

Preferably, in step 1, the mass ratio of zinc phosphate to aluminum tripolyphosphate is (1.2-2):1.

Preferably, in step 2, the mass ratio of aniline and the mixture powder in step 1 is (1-4):1.

Preferably, in step 2, the pH adjuster is phosphoric acid, phosphorous acid, phenylphosphonic acid, dibutyl phosphate, hydrochloric acid, sulfuric acid, glacial acetic acid, phytic acid, polymethacrylic acid, dodecyl benzene sulfonate One or more of acid and sulfosalicylic acid.

Preferably, in step 3, the oxidizing agent is hydrogen peroxide, sodium hypochlorite, hypochlorous acid, ammonium persulfate, potassium persulfate, potassium iodate, ferric chloride, potassium dichromate, potassium permanganate, perchlorate One or more acids; the added amount is 1 to 5 times the mass of aniline.

Preferably, the preparation method of the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating is: mix component A and component B in proportion and stir evenly to obtain polyaniline-zinc phosphate-tripolyphosphate. Aluminum polyphosphate composite water-based epoxy resin anti-corrosion coating.

Preferably, the method of using the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating is: coating on the pre-treated metal surface and curing at room temperature.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention uses mechanical dispersion and chemical polymerization methods to polymerize polyaniline on the surface of zinc phosphate and aluminum tripolyphosphate to form a polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material. Through organic polyaniline and inorganic zinc phosphate, The combination of aluminum tripolyphosphate not only improves the problems of poor dispersion and poor processability of polyaniline, but also optimizes the problem that zinc phosphate and aluminum tripolyphosphate easily absorb water and weaken the anti-corrosion effect. At the same time, the three components cooperate with each other and pass different The anti-corrosion mechanism creates an excellent metal protective barrier. Due to the improved dispersion, the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material can be introduced into the water-based epoxy resin system to prepare the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating to achieve green For the purpose of environmental protection, it also enhances the mechanical properties and chemical corrosion resistance of epoxy resin.

2. In the present invention, zinc phosphate and aluminum tripolyphosphate are mechanically ground to form inorganic mixture particles with consistent particle sizes and evenly dispersed, and then polyaniline is coated on the surface of the inorganic particles in an acidic environment to form polyaniline-phosphoric acid. Zinc-aluminum tripolyphosphate composite anti-corrosion material. The generated polyaniline has good conductivity and can effectively exert its electrochemical anti-corrosion ability, and the dopant anions in it also have corrosion inhibition effects. Polyaniline molecules are evenly attached to the surface of inorganic particles and are smoothly integrated into the water-based coating system through the interface of inorganic particles. This solves the problems of poor dispersion and poor processability of polyaniline and gives full play to the anti-corrosion effect of polyaniline. As an organic molecule, polyaniline plays a physical shielding role for inorganic particles of zinc phosphate and aluminum tripolyphosphate, effectively reducing the water absorption of inorganic particles and improving the water resistance of the coating system.

3. The present invention uses polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, and generates a dense metal oxide layer between the metal and the coating through the reversible redox characteristics of polyaniline itself. At the same time, it cooperates with zinc phosphate and metal to form The phosphating film, the tripolyphosphate anti-rust group of aluminum tripolyphosphate and the passivation film formed by metal chelation work together to establish an excellent and long-lasting metal protective barrier. In addition, the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material can also strengthen the adhesion between the coating and the metal, improve the weather resistance of the coating, and has the advantage of scratch resistance.

4. The present invention introduces the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material into the water-based epoxy coating system. On the basis of the wear resistance, corrosion resistance and strong adhesion of the epoxy resin coating itself, it further improves the coating's resistance to corrosion. Chemical corrosion properties and mechanical properties.

5. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating of the present invention adopts green and environmentally friendly materials with no side effects on the human body and the environment. It does not use xylene, n-butanol, benzyl alcohol and other organic materials. Solvent, reduce VOC emissions, achieve environmental friendliness, simple process, convenient application and good stability.

Detailed ways

In order to facilitate a better understanding of the present invention, the following examples are provided. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention.

Example 1

A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, its preparation method includes the following steps:

(1) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material: Add water, zinc phosphate, and aluminum tripolyphosphate to a sand mill to prepare a 20% dispersion and fully sand for 1 hour, in which zinc phosphate and The mass ratio of aluminum tripolyphosphate is 1.2:1, and then filtered, dried, and pulverized to obtain a mixture powder; add aniline and mixture powder with a mass ratio of 4:1 to water and stir thoroughly, then add concentrated sulfuric acid, and adjust the pH value to 1.5, control the temperature to 2°C; then dissolve 1 times the mass of aniline in ammonium persulfate in a little water, add it drop by drop into the above mixture solution, react fully for 24 hours, collect the solid by suction filtration, and wash it twice with methanol and 2 times with water. times, and finally dried and crushed at 80°C to obtain the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material;

(2) Preparation of component A: Mix 30 parts of bisphenol A epoxy resin with an epoxy value of 41, 2 parts of 731A dispersant, 1 part of Dow Corning AFE-3168 defoamer, and 5 parts of RM-12W Emulsifier, 4 parts of water, 25 parts of the above polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 9 parts of talc powder, 5 parts of barium sulfate, 2 parts of titanium dioxide, 4 parts of KH-580 silane coupling agent, 6 parts of propylene glycol phenyl ether film-forming additive, 3 parts of BYK-331 leveling agent, and 4 parts of cobalt green were added to the high-speed dispersing sand mill under low-speed stirring at 500r/min, and then high-speed dispersing sanding at 1500r/min for 6 hours. Pass through a 300 mesh sieve to obtain component A;

(3) Preparation of component B: Add 98 parts of polyamide epoxy resin curing agent, 1 part of 731A dispersant, and 1 part of Dow Corning AFE-3168 defoaming agent to high-speed dispersion sand grinding under low-speed stirring at 500r/min. machine, followed by high-speed dispersion sand grinding at 1000r/min for 1 hour, and passing through a 300-mesh screen to obtain component B;

(4) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating: Mix the above component A and component B according to the mass ratio of 5:1.3 and stir for 10 minutes until they are in a uniform state to obtain polyaniline. -Zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Example 2

A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, its preparation method includes the following steps:

(1) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material: add water, zinc phosphate, and aluminum tripolyphosphate to a sand mill to prepare a 20% dispersion and fully sand for 3 hours, in which zinc phosphate and aluminum tripolyphosphate The mass ratio of aluminum tripolyphosphate is 1.4:1, and then filtered, dried, and pulverized to obtain a mixture powder; add aniline and mixture powder with a mass ratio of 2:1 to water and stir thoroughly, then add concentrated sulfuric acid, and adjust the pH value to 2.8, control the temperature to 5°C; then dissolve 5 times the mass of aniline in ammonium persulfate and potassium persulfate in a little water, add dropwise to the above mixture solution, react fully for 20h, collect the solid by suction filtration, and wash it twice with methanol , washed with water twice, and finally dried and pulverized at 80°C to obtain polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material;

(2) Preparation of component A: Mix 40 parts of bisphenol A epoxy resin with an epoxy value of 51, 1 part of BYK-190 dispersant, 2 parts of TEGO-810 defoaming agent, and 2 parts of RM-8W type emulsifier, 11 parts of water, 16 parts of the above polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 5 parts of talc powder, 7 parts of barium sulfate, 8 parts of titanium dioxide, 1 part of KH-561 silane coupling agent , 1 part of dodecanol ester film-forming additive, 1 part of BYK-333 leveling agent, and 5 parts of iron red were added to the high-speed dispersing sand mill under low-speed stirring at 500r/min, and then high-speed dispersing sanding at 1500r/min. 6h, pass through a 300 mesh screen to obtain component A;

(3) Preparation of component B: Add 96 parts of phenolic amine epoxy resin curing agent, 2 parts of BYK-190 dispersant, and 2 parts of TEGO-810 defoaming agent under low-speed stirring at 500r/min. In a high-speed dispersing sand mill, it is then subjected to high-speed dispersing sand grinding at 1000r/min for 1 hour, and passed through a 300-mesh screen to obtain component B;

(4) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating: Mix the above component A and component B according to the mass ratio of 5:1.1 and stir for 10 minutes until they are in a uniform state to obtain polyaniline. -Zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Example 3

A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, its preparation method includes the following steps:

(1) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material: add water, zinc phosphate, and aluminum tripolyphosphate to a sand mill to prepare a 20% dispersion and fully sand for 4 hours, in which zinc phosphate and The mass ratio of aluminum tripolyphosphate is 2:1, and then filtered, dried, and crushed to obtain a mixture powder; add aniline and mixture powder with a mass ratio of 1:1 to water and stir thoroughly, then add phosphoric acid with a concentration of 85%, and adjust The pH value is 3.5, and the control temperature is 10°C; then dissolve 3 times the mass of aniline ferric chloride in a little water, add it drop by drop into the above mixture solution, fully react for 10 hours, collect the solid by suction filtration, and wash it twice with methanol. Wash with water twice, and finally dry and pulverize at 80°C to obtain polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material;

(2) Preparation of component A: Mix 47 parts of bisphenol A epoxy resin with an epoxy value of 54, 1 part of BYK-155 dispersant, 1 part of BYK-A530 defoaming agent, 1 part of polyethylene Oxyethylene octylphenol ether-10 emulsifier, 7 parts water, 10 parts above polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 3 parts talc, 9 parts barium sulfate, 5 parts titanium dioxide, 2 parts KH -560 type silane coupling agent, 3 parts of propylene glycol butyl ether film-forming aid, 2 parts of BYK-378 leveling agent, and 9 parts of cobalt yellow were added to the high-speed dispersing sand mill under low-speed stirring at 500r/min, and then 1500r/min High-speed dispersion sand grinding for 6 hours, passing through a 300-mesh screen to obtain component A;

(3) Preparation of component B: Mix 90 parts of modified polyamide epoxy resin curing agent, 5 parts of BYK-155 dispersant, and 5 parts of BYK-A530 defoaming agent respectively under low-speed stirring at 500r/min. Add it to a high-speed dispersing sand mill, and then grind it at a high speed of 1000r/min for 1 hour, and then pass through a 300-mesh screen to obtain component B;

(4) Preparation of polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating: Mix the above component A and component B according to the mass ratio of 5:0.7 and stir for 10 minutes to obtain a uniform state, that is, polyaniline is obtained -Zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Comparative example 1

Polyaniline synthesized by conventional emulsion polymerization is used to prepare water-based epoxy resin anticorrosive coatings. The preparation method includes the following steps:

(1) Preparation of polyaniline: Under stirring, prepare aniline, OP-10, dodecylbenzene sulfonic acid, and water into an emulsion according to the mass ratio of 1:1:2:120, then add concentrated sulfuric acid to adjust the pH value is 2.8, control the temperature to 5°C; then dissolve ammonium persulfate and potassium persulfate with 5 times the mass of aniline in a little water and add them dropwise into the above emulsion, fully react for 20 hours, collect the solid by suction filtration, and wash it twice with methanol. Wash with water twice, and finally dry and pulverize at 80°C to obtain polyaniline.

(2) Preparation of component A: Mix 40 parts of bisphenol A epoxy resin with an epoxy value of 51, 1 part of BYK-190 dispersant, 2 parts of TEGO-810 defoaming agent, and 2 parts of RM-8W type emulsifier, 11 parts of water, 4 parts of the above-mentioned polyaniline, 7 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, 5 parts of talc, 7 parts of barium sulfate, 8 parts of titanium dioxide, 1 part of KH-561 silane coupling Agent, 1 part of dodecanol ester film-forming additive, 1 part of BYK-333 leveling agent, and 5 parts of iron red were added to the high-speed dispersing sand mill under low-speed stirring at 500r/min, and then the sand was dispersed at 1500r/min high-speed. Grind for 6 hours and pass through a 300-mesh screen to obtain component A;

(3) Preparation of component B: Add 96 parts of phenolic amine epoxy resin curing agent, 2 parts of BYK-190 dispersant, and 2 parts of TEGO-810 defoaming agent to high-speed dispersing sand under low-speed stirring at 500r/min. In the mill, it is then subjected to high-speed dispersion sand grinding at 1000r/min for 1 hour, and passed through a 300-mesh screen to obtain component B;

(4) Preparation of water-based epoxy resin anti-corrosion coating: Mix the above-mentioned component A and component B according to the mass ratio of 5:1.1 and stir for 10 minutes to achieve a uniform state, thereby obtaining a water-based epoxy resin anti-corrosion coating.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Comparative example 2

Comparative Example 2 adopts the method of Example 1 in the invention patent "A lignosulfonic acid/polyaniline/poly(3,4-ethylenedioxythiophene) composite antistatic coating and its preparation and application" (publication number: CN112266699A) Preparation methods to prepare coatings.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Comparative example 3

Comparative Example 3 adopts the preparation method of Example 1 in the invention patent "Anti-corrosion coating for ship bottom layer and its preparation method" (publication number: CN109517484A) to prepare the coating.

After washing and drying the polished tinplate with acetone and ethanol, use an air spray gun and air compressor to evenly spray the above paint on the tinplate, and let it stand for drying and curing at room temperature for 24 hours to obtain the coating.

Comparative example 4

It is basically the same as Example 2. The only difference is that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is not added, and the preparation process steps of the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material are accordingly omitted.

Comparative example 5

Basically the same as Example 2, the only difference is that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is replaced by polyaniline. Step (1) is the preparation method of polyaniline: aniline, OP- 10. Prepare dodecylbenzenesulfonic acid and water into an emulsion according to the mass ratio of 1:1:2:120, then add concentrated sulfuric acid, adjust the pH value to 2.8, and control the temperature to 5°C; then add 5 times the mass of aniline Ammonium persulfate and potassium persulfate were dissolved in a little water and added dropwise to the above emulsion, and allowed to react fully for 20 hours. The solids were collected by suction filtration, washed twice with methanol and twice with water, and finally dried and crushed at 80°C to obtain polyaniline.

Comparative example 6

It is basically the same as Example 2. The only difference is that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is replaced with zinc phosphate and is used directly.

Comparative example 7

It is basically the same as Example 2. The only difference is that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is replaced with aluminum tripolyphosphate and is used directly.

Performance testing experiments

1. Test the coating performance according to the following methods:

1. Observe the dispersion of the material in the paint with the naked eye. If the paint has no hard lumps and is in a uniform state, it is regarded as "well dispersed". The dispersion is divided into three situations: good dispersion, average dispersion and poor dispersion.

2. Measure the surface drying time and actual drying time of the paint film according to "GB/T 1728-2020 Method for determination of drying time of paint film and putty film".

3. Observe the morphology of the paint film with the naked eye. If the paint film is uniform in color, flat and smooth, and has no obvious sagging, bubbling, etc., then it is considered as "the appearance of the paint film is normal", and the appearance of the paint film is divided into normal and abnormal. Two situations.

4. Conduct the adhesion test of the coating according to "GB/T 9286-2021 Cross-hatch Test for Paints and Varnishes". It uses a test method that cuts the coating with a right-angle grid pattern and penetrates into the substrate to evaluate the resistance of the coating to detach from the substrate. The test results are divided into grades 0 to 5, with grade 0 being the best. Among them, For general purposes Class 0 to Class 1 are satisfactory.

5. Carry out the salt spray resistance test of the coating according to "GB/T 1771-2007 Determination of neutral salt spray resistance of paints and varnishes" to test the neutral salt spray resistance of the coating.

6. Carry out the water resistance test of the coating according to "GB/T 1733-1993 Paint Film Water Resistance Determination Method", and use Method A (water immersion test method) to test the water resistance of the coating.

2. The relevant performance data of the coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 7 are shown in Table 1.

Table 1 Coating performance data of Examples 1 to 3 and Comparative Examples 1 to 7

It can be seen from Table 1 that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating prepared in Examples 1 to 3 of the present invention has uniform components, is not easy to agglomerate, and is well dispersed. The surface drying time is within 25 minutes. The drying time is within 8.5 hours. The produced coating film is smooth and smooth with normal appearance. The adhesion test is ≤1 level. The salt spray resistance can reach more than 1200 hours and the water resistance can reach more than 1512 hours. Among them, the coating performance of Example 2 is better. , the adhesion is level 0, there is no abnormality in salt spray resistance for 1416h, and there is no abnormality in water resistance for 1632h, indicating that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anticorrosive coating according to the invention has good dispersion, adhesion, Excellent salt spray and water resistance.

In Comparative Example 1, polyaniline synthesized by conventional emulsion polymerization was used to prepare the coating. The coating had more settled particles, individual agglomerates, and average dispersion. The resulting coating film had more particles, had abnormal appearance, and had reduced adhesion. , salt spray resistance and water resistance are relatively poor, indicating that polyaniline synthesized by conventional emulsion polymerization is difficult to disperse evenly in water-based epoxy coatings, resulting in the anti-corrosion performance of the coating being affected.

Comparative Example 2 uses the coating of Example 1 in the invention patent CN112266699A. Its salt spray resistance and water resistance are poor, indicating that its anti-corrosion performance is average.

Comparative Example 3 uses the coating of Example 1 in the invention patent CN109517484A. It has more settled particles and average dispersion. The prepared coating film has more particles and an abnormal appearance. Its salt spray resistance and water resistance are poor, which shows that its It failed to effectively solve the problem of poor dispersion of polyaniline components and failed to give full play to the anti-corrosion ability of polyaniline.

Comparative Example 4 did not add polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion materials. Comparative Examples 5 to 7 replaced the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion materials with polyaniline, zinc phosphate, and tripolyphosphate respectively. Aluminum, among which Comparative Example 4 did not add effective anti-corrosion pigments, resulting in poor anti-corrosion performance. Comparative Example 5 was affected by polyaniline and had more sedimentation particles, average dispersion, and reduced the anti-corrosion performance of the coating. Comparative Examples 6 to 7 only added a single Anti-corrosion pigments have limited anti-corrosion effect and poor salt spray resistance and water resistance.

It can be seen that the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to the present invention has significant progress compared with the existing technology, and improves the performance of polyaniline in the water-based epoxy resin anti-corrosion coating. Medium dispersion, polyaniline, zinc phosphate, and aluminum tripolyphosphate three anti-corrosion materials work together to provide excellent and long-lasting anti-corrosion properties.

The above descriptions are only preferred embodiments of the present invention and do not limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating, which is characterized in that: it includes component A and component B, and the mass ratio of component A to component B is 5: (0.7～1.3); The A component includes: 30 to 47 parts of epoxy resin, 10 to 25 parts of polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, 3 to 10 parts of talc powder, 5 to 12 parts of barium sulfate, and 2 parts of titanium dioxide. ~11 parts, dispersant 1-2 parts, defoaming agent 1-2 parts, emulsifier 1-5 parts, silane coupling agent 1-4 parts, film-forming aid 1-6 parts, leveling agent 1-3 parts parts, 3 to 10 parts of other additives, 3 to 11 parts of water; The B component includes: 90 to 98 parts of epoxy resin curing agent, 1 to 5 parts of dispersant, and 1 to 5 parts of defoaming agent. 2. Polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 1, characterized in that: The epoxy resin is one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, and glycidyl amine type epoxy resin with an epoxy value of 41 to 54. species or species; The dispersant is polyacrylate sodium salt solution, polycarboxylic acid sodium salt solution, modified styrene maleic acid copolymer solution, modified polyether solution, Dow 731A, BYK-155, BYK- 190. One or more of BYK-192; The defoaming agent is one of concentrated silicone, polyethersiloxane copolymer emulsion, silicone polymer emulsion, Dow Corning AFE-3168, TEGO-8030, TEGO-810, BYK-A530 species or species; The emulsifier is one or more of modified polyurethane, polyoxyethylene octylphenol ether-10, Dow RM-12W, and Dow RM-8W; The silane coupling agent is 3-glycidoxypropyltrimethoxysilane (KH-560), 3-(2,3-epoxypropoxy)propyltriethoxysilane (KH-561), One or more of 3-mercaptopropyltriethoxysilane (KH-580) and 3-aminopropyltriethoxysilane (KH-550); The film-forming assistant is one or more of dodecyl alcohol ester, cetyl alcohol ester, propylene glycol phenyl ether, and propylene glycol butyl ether; The leveling agent is one of polyether-modified polydimethylsiloxane, fluorocarbon-modified polyacrylate, BYK-331, BYK-333, BYK-378, and BASF EFKAFL 3772. species or species; The other additives are one or more of iron red, manganese violet, iron blue, cobalt yellow, iron yellow, carbon black, manganese black, cobalt green, chrome green, and zinc white; The epoxy resin curing agent is one or more of polyamide, phenolic amine, and modified polyamide. 3. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 1, characterized in that: the preparation method of component A is: adding epoxy resin, dispersant, defoaming Agent, emulsifier, water, polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material, talc, barium sulfate, titanium dioxide, silane coupling agent, film-forming additive, leveling agent, and other additives are stirred at low speed. Then add them into a high-speed dispersing sand mill, and then grind them for 2 to 8 hours at a high speed, and then sieve to obtain component A. 4. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 1, characterized in that: the preparation method of component B is: adding epoxy resin curing agent, dispersant, The defoaming agent is added to the high-speed dispersing sand mill under low-speed stirring, followed by high-speed dispersing sand milling for 1 to 3 hours, and sieved to obtain component B. 5. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 1, characterized in that the preparation method of the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material is as follows : Step 1: Add water, zinc phosphate, and aluminum tripolyphosphate into a sand mill and grind thoroughly for 1 to 4 hours. After filtering, drying, and pulverizing, the mixture powder is obtained; Step 2: Add aniline and the mixture powder in step 1 to the water and stir thoroughly, add a pH adjuster, adjust the pH value to 1.5 to 3.5, and control the temperature to 2 to 10°C; Step 3: Prepare the oxidant solution, add it dropwise to the dispersion in step 2, fully react for 10 to 24 hours, and obtain the polyaniline-zinc phosphate-aluminum tripolyphosphate composite anti-corrosion material after separation, washing, and drying. 6. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 5, characterized in that: in step 1, the mass ratio of zinc phosphate to aluminum tripolyphosphate is (1.2~2 ):1. 7. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 5, characterized in that: in step 2, the mass ratio of aniline and the mixture powder in step 1 is (1~ 4):1. 8. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 5, characterized in that: in step 2, the pH regulator is phosphoric acid, phosphorous acid, phenylphosphine One or more of acid, dibutyl phosphate, hydrochloric acid, sulfuric acid, glacial acetic acid, phytic acid, polymethacrylic acid, dodecylbenzenesulfonic acid, and sulfosalicylic acid. 9. The polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating according to claim 5, characterized in that: in step 3, the oxidizing agent is hydrogen peroxide, sodium hypochlorite, hypochlorous acid, One or more of ammonium persulfate, potassium persulfate, potassium iodate, ferric chloride, potassium dichromate, potassium permanganate, and perchloric acid; the mass is 1 to 5 times the mass of aniline. 10. A method for preparing the polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anticorrosive coating according to any one of claims 1 to 9, characterized in that: the A component and the B component Mix and stir evenly according to the proportion to obtain polyaniline-zinc phosphate-aluminum tripolyphosphate composite water-based epoxy resin anti-corrosion coating.