Phosphorus-free salt-spray-resistant 1000-hour environment-friendly epoxy coating and preparation method thereof

Abstract

The invention relates to the field of novel coating compositions, and particularly discloses a phosphorus-free salt-spray-resistant 1000-hour environment-friendly epoxy coating and a preparation method thereof, and the phosphorus-free salt-spray-resistant 1000-hour environment-friendly epoxy coating comprises a component A and a component B, comprising the following raw materials in parts by weight: 35-40 parts of epoxy resin, 2-2.5 parts of n-butyl alcohol, 5-5.5 parts of xylene, 0.1-0.5 part of a dispersing agent, 10-12 parts of iron oxide red, 4-6 parts of ground calcium carbonate, 2-4 parts of zinc oxide, 4-6 parts of anti-rust silicon powder, 4-6 parts of kaolin, 3-4 parts of talcum powder, 7-8 parts of anti-rust pigment, 12-15 parts of precipitated barium sulphate, 4-5 parts of petroleum resin and 0.02-0.06 part of a flatting agent. 12-15 parts of a curing agent, 1-2 parts of n-butyl alcohol, 1-1.5 parts of xylene, 1-3 parts of a dispersing agent and 0.4-0.6 part of mica iron oxide; the talcum powder comprises one or more of calcium ion exchange talcum powder, cerium ion exchange talcum powder and lanthanum ion exchange talcum powder. The coating disclosed by the invention is environment-friendly, phosphorus-free and good in salt spray resistance.

Description

Technical Field

[0001] The present application relates to the field of novel coating compositions, and more specifically, it relates to an environmentally friendly epoxy coating that is phosphorus-free and has a salt spray resistance of 1000 hours and a preparation method thereof. Background Art

[0002] In the modern industrial field, especially in the construction machinery manufacturing, the protective coating plays a crucial role in the long-term performance and durability of the equipment. As a common protective coating, the epoxy primer has many advantages. With the continuous development of the construction machinery industry, the requirements for the coating are increasing day by day. When facing complex working environments and harsh climatic conditions, such as the anti-rust primers for offshore wind power operation platforms, large ships, port equipment, etc., traditional primers need to have higher salt spray resistance, higher adhesion, and higher environmental protection requirements. Existing anti-rust primers usually generate a passivation layer for rust prevention by adding phosphorus-based raw materials such as aluminum tripolyphosphate, zinc phosphate, and phosphorus iron powder, which cannot meet the environmental protection requirements, cause eutrophication of water bodies, and at the same time have insufficient film densification, so that chloride ions are easy to penetrate and cause electrochemical corrosion. The anti-rust pigments such as zinc phosphate have poor interfacial bonding with the resin and are easy to form pores, and are easy to blister or peel off in a salt spray environment, resulting in the failure of protection. For various reasons, the anti-rust coating cannot effectively resist the erosion of salt spray, and the salt spray test is generally less than 500 hours.

[0003] There is a need to find an alternative raw material solution to meet the use requirements of construction machinery under various extreme conditions, and it has become an inevitable trend to develop an epoxy anti-rust primer that is phosphorus-free, highly efficient in anti-salt spray and has high performance. Summary of the Invention

[0004] In order to ensure that the epoxy primer is phosphorus-free and has a stable salt spray resistance of more than 1000 hours, the present application provides an environmentally friendly epoxy coating that is phosphorus-free and has a salt spray resistance of 1000h and a preparation method thereof.

[0005] In the first aspect, the present application provides an environmentally friendly epoxy coating that is phosphorus-free and has a salt spray resistance of 1000h, including component A and component B; Component A includes the following raw materials in parts by weight: 35-40 parts of epoxy resin, 2-2.5 parts of n-butanol, 5-5.5 parts of xylene, 0.1-0.5 part of dispersant, 10-12 parts of iron oxide red, 4-6 parts of heavy calcium carbonate, 2-4 parts of zinc oxide, 4-6 parts of anti-rust silicon powder, 4-6 parts of kaolin, 3-4 parts of talc powder, 7-8 parts of ST anti-rust pigment, 12-15 parts of precipitated barium sulfate, 4-5 parts of petroleum resin, 0.02-0.06 part of leveling agent; Component B includes the following raw materials in parts by weight: 12-15 parts of curing agent, 1-2 parts of n-butanol, 1-1.5 parts of xylene, 1-3 parts of dispersant, 0.4-0.6 part of micaceous iron oxide; The talcum powder includes one or more of calcium ion-exchanged talcum powder, cerium ion-exchanged talcum powder, and lanthanum ion-exchanged talcum powder.

[0006] By adopting the above scheme, using epoxy resin as the matrix component, adding iron oxide red and anti-rust silicon powder to reduce coating pores and delay the penetration of salt spray medium. Precipitated barium sulfate has high chemical inertness to reduce the shrinkage of the coating and prevent crack generation. Talcum powder has a certain layered structure to extend the diffusion path of the salt spray medium. The above superimposed effects are used for physical anti-rust. By defining that the talcum powder includes calcium ion-exchanged talcum powder, cerium ion-exchanged talcum powder, and lanthanum ion-exchanged talcum powder, the introduction of calcium ions reduces the surface polarity of the talcum powder, enhances the compatibility with epoxy resin. At the same time, the alkalinity of calcium helps to neutralize acidic corrosion media, improve the salt spray resistance performance, and can also react with strontium chromate yellow to form stable compounds such as CaCrO4 to inhibit electrochemical corrosion. At the same time, Ce 3+ has high redox activity, neutralizes Cl - and forms a stable CeO2 passivation film to inhibit the corrosion of the metal matrix. La 3+ combines with Cl - to form LaCl3 precipitate, reducing the concentration of free Cl-. At the same time, it stabilizes the coating interface through coordination. At the same time, Ce 3+ and La 3+ have higher charge density and ionic radius. The modified talcum powder forms a denser interlayer structure. When used together with calcium ion talcum powder, the maze effect is further enhanced.

[0007] By adding a certain mass of petroleum resin to balance hardness and flexibility and reduce the salt spray failure caused by internal stress. By adding a certain mass of strontium chromate yellow and anti-rust pigments to cover the anode and cathode to provide double protection, isolate the corrosion medium, and repair the damaged area by dissolution and reprecipitation at the same time, the protective performance of the coating film is more stable. Anti-rust silicon powder can generate silicate ions under salt spray. The silicate ions combine with the iron ions ionized from the anode and the calcium ions on the surface of the anti-rust pigment and in the coating to form Fe2(SiO3)3 and CaSiO3. These two silicates are insoluble and have stable chemical properties. They migrate to the metal surface to form a passivation layer, thus preventing the continuous occurrence of electrochemical reactions on the metal surface and playing a long-term and effective protective role to prevent metal corrosion. By using n-butanol and xylene together to adjust the coating viscosity and volatilization rate, the coating tension is relatively uniform, the surface flatness is relatively high, and it is not easy to crack or bulge. By adding a certain amount of n-butanol and xylene to component B, the dispersion in the coating system is more uniform and the curing is more complete. By adding a certain mass of mica iron oxide, the flaky structure further extends the penetration path of salt spray and further reduces the shrinkage of the coating, prolonging the stability of salt spray resistance.

[0008] In a specific embodiment, the talcum powder includes calcium ion-exchanged talcum powder, cerium ion-exchanged talcum powder, and lanthanum ion-exchanged talcum powder, and the mass ratio is 1:(1.5 - 2.5):(2 - 2.1).

[0009] By adopting the above scheme, the mass ratio of the three ion-exchanged talcum powders is limited. It may be because the interlayer structures of the talcum powders prepared by ions with different charge densities and ionic radii have different degrees of compactness at this time. The internal tension of the system is relatively uniform and not easy to generate gaps. After being used together, the maze effect is more significant. At the same time, ions with different redox activities form a passivation film with chloride ions in sequence, further delaying the corrosion process.

[0010] In a specific embodiment, the talcum powder is chemically etched talcum powder, and the etching steps include: adding the talcum powder to a mixed solution of hydrofluoric acid and hydrochloric acid, stirring, filtering, washing, and drying to obtain chemically etched talcum powder.

[0011] Preferably, the particle size of the talcum powder is 4 - 15 μm, the concentration of hydrochloric acid is 4 mol / L, the concentration of hydrofluoric acid is 1.5 mol / L, the volume ratio of hydrochloric acid to hydrofluoric acid is (3 - 4):1, and the etching time is 0.5 - 1.5 hours.

[0012] By adopting the above scheme, the chemical etching effect is good. The prepared talcum powder has a larger specific surface area, good ion exchange effect, more surface-activated hydroxyl groups, better ion exchange effect, and is more stable in the system and not easy to settle.

[0013] In a specific embodiment, the talcum powder is also modified with an epoxy group silane coupling agent.

[0014] By adopting the above scheme, after being modified with an epoxy group silane coupling agent, it has better compatibility with the matrix of epoxy resin, is more evenly dispersed, the layered structure can better protect the matrix, and at the same time can participate in curing. The prepared coating film is more dense, and it is more difficult for salt spray to penetrate.

[0015] In a specific embodiment, the mica iron oxide includes dopamine-modified mica iron oxide, and the preparation steps include: adding the mica iron oxide to a dopamine hydrochloride solution, stirring evenly, adjusting the pH value, adding a silane coupling agent, and heating and reacting to obtain dopamine-modified mica iron oxide.

[0016] By adopting the above scheme, the modified mica iron oxide is more evenly and stably distributed in component B, extending the diffusion path of the corrosion medium. Dopamine participates in curing, the prepared coating film is more dense, and the mica iron oxide maintains a tile-like stacking more stably in the system, and has a good effect of blocking water vapor and corrosion medium.

[0017] In a specific embodiment, the epoxy equivalent of the epoxy resin is 400 - 500 eq / 100g, the curing agent is an amine curing agent, and the amine value is 500 - 600 mgKOH / g.

[0018] By adopting the above - mentioned scheme, the parameters of the epoxy resin and the curing agent are more suitable for the raw material setting of this application. The obtained coating film is fully cured, with uniform tension, flat, dense and stable.

[0019] In a specific embodiment, the mass ratio of the epoxy resin, the curing agent, the epoxy - modified exchanged talc powder, and the dopamine - modified mica iron oxide is 35 - 40:12 - 15:3 - 4:0.5 By adopting the above - mentioned scheme, the modified talc powder and the dopamine - modified mica iron oxide have good effects in participating in curing. In the obtained coating film, the stacked structure of the talc powder and the mica iron oxide is stable and flat. The coating film is not easy to generate bubbles and cracks due to uneven tension, the tension of the coating film is more uniform, and the salt - spray resistance performance is more stable.

[0020] In a specific embodiment, the average particle size of the mica iron oxide is 5 - 20 μm.

[0021] By adopting the above - mentioned scheme, the particle size of the mica iron oxide is suitable for the raw material setting of this application, with uniform and stable distribution and good salt - spray resistance effect.

[0022] In the second aspect, the present application provides a preparation method of an environmentally friendly epoxy coating with 1000 - hour phosphorus - free salt - spray resistance, including the following steps: Weigh the raw materials of components A and B by mass parts respectively and set aside. Mix the epoxy resin, n - butanol, and xylene, add a dispersant, and stir at a low speed for 5 - 10 min. After adding iron oxide red and anti - rust pigments and dispersing until there is no dry powder on the liquid surface, stir at a high speed for 25 - 35 min, seal and soak for 1 - 1.5 hours, and then stir at a high speed for 10 - 15 min; Add the remaining raw materials of component A under the condition of medium - speed stirring, continue to stir for 5 - 10 min, and obtain component A. Stir the raw materials of component B at a medium speed for 10 - 15 min, add them to component A, and mix evenly to obtain an environmentally friendly epoxy coating with 1000 - hour phosphorus - free salt - spray resistance.

[0023] By adopting the above - mentioned scheme, the preparation method is simple, the components in the coating are uniformly and stably dispersed, not easy to precipitate, and can form a good protection effect on the substrate.

[0024] In a specific embodiment, the low - speed stirring speed is 50 - 300 r / min, the medium - speed stirring speed is 350 - 450 r / min, and the high - speed stirring speed is 500 - 1000 r / min.

[0025] By adopting the above scheme, the raw material setting more suitable for this application is achieved. The raw materials are evenly mixed, and the molecular structure is not damaged at the same time. Moreover, the coating prepared has a good effect on controlling air bubbles, and the cured coating is smoother and flatter.

[0026] In summary, this application has the following beneficial effects: This application details the components and mass parts of the coating with epoxy resin as the main component, enabling the prepared coating to have good protection effects on the substrate such as physical barrier, passivation film protection, and cathodic and anodic protection. At the same time, by using calcium ion-exchanged talc powder, cerium ion-exchanged talc powder, and lanthanum ion-exchanged talc powder in a certain mass ratio together, layered structures with different degrees of denseness are arranged alternately, and ions with different redox activities form passivation films in sequence. The prepared coating film has both good protection effects and relatively uniform tension, is not easy to warp, and has a good maze effect.

[0027] By further modifying talc powder with epoxy-based silane coupling agent and modifying mica iron oxide in component B with dopamine, enabling the two to participate in curing, and by further defining the parameters of epoxy resin and curing agent and their mass ratio, the prepared coating cures sufficiently, has uniform tension, is dense and not easy to produce cracks and warp. The prepared coating film can stably achieve high salt spray resistance performance.

[0028] This application also provides a preparation method of the coating. By adding different raw materials in sequence and defining the stirring speed, the raw materials are stirred evenly without damaging the molecular structure, with fewer air bubbles, further improving the salt spray resistance effect of the prepared coating. Specific embodiments

[0029] The following further elaborates on this application with reference to examples and comparative examples.

[0030] To further assist in understanding the technical solution of the present invention, several specific examples are provided to more specifically describe the technical solution of the present invention. All these described examples are only partial examples of the present invention, not all; the examples can be combined with each other, and the same or similar concepts or processes may not be repeated in some examples. The following examples are further explanations of the present invention, and the present invention is not limited thereto.

[0031] The chemical reagents in the examples and comparative examples, if not specified, are commercially available conventional reagents. The epoxy equivalent of the epoxy resin is 450 - 500 eq / 100 g, purchased from Baling Petrochemical CYD-011; the amine value of the curing agent is 500 - 600 mgKOH / g, purchased from Baling Petrochemical T31; the dispersant is purchased from BYK-104S of BYK Germany; the leveling agent is purchased from BYK-VP—354 of BYK Germany.

[0032] Preparation examples Preparation Example 1: Ion-exchanged talc powder: Calcium ion-exchanged talc powder: Add 50 g of 1000-mesh talc powder to 120 ml of 0.8 mol / L CaCl2 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, and dry at 80 °C to obtain calcium ion-exchanged talc powder.

[0033] Cerium ion-exchanged talc powder: Add 50 g of 1000-mesh talc powder to 120 ml of 0.8 mol / L Ce(NO3)3 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, dry and crush at 80 °C to obtain cerium ion-exchanged talc powder.

[0034] Lanthanum ion-exchanged talc powder Add 50 g of 1000-mesh talc powder to 120 ml of 0.8 mol / L La(NO3)3 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, and dry at 80 °C to obtain lanthanum ion-exchanged talc powder.

[0035] Preparation Example 2: Ion-exchanged chemically etched talc powder: Mix 90 ml of 4 mol / L hydrochloric acid and 30 ml of 1.5 mol / L hydrofluoric acid evenly, add 50 g of 1000-mesh talc powder, stir evenly, filter after 1 hour, wash, and dry at 80 °C to obtain chemically etched talc powder for standby.

[0036] Calcium ion-exchanged chemically etched talc powder: Add 50 g of 1000-mesh chemically etched talc powder to 120 ml of 0.8 mol / L CaCl2 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, and dry at 80 °C to obtain calcium ion-exchanged chemically etched talc powder.

[0037] Cerium ion-exchanged chemically etched talc powder: Add 50 g of 1000-mesh chemically etched talc powder to 120 ml of 0.8 mol / L Ce(NO3)3 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, and dry at 80 °C to obtain cerium ion-exchanged chemically etched talc powder.

[0038] Lanthanum ion-exchanged chemically etched talc powder Add 50 g of 1000-mesh chemically etched talc powder to 120 ml of 0.8 mol / L La(NO3)3 solution, stir at 120 r / min at 90 °C for 2.5 hours, filter, wash with deionized water, and dry at 80 °C to obtain lanthanum ion-exchanged chemically etched talc powder.

[0039] Preparation Example 3: Epoxy Silane Coupling Agent Modified Ion Exchange Chemically Etched Talc Powder Epoxy Silane Coupling Agent Modified Calcium Ion Exchange Chemically Etched Talc Powder Add 50 g of the calcium ion exchange chemically etched talc powder prepared in Preparation Example 2 into 1100 ml of 60% wt ethanol aqueous solution, then ultrasonically disperse it for 30 minutes at a power of 300 W, add 18 g of silane coupling agent KH-172, stir and react at 85 °C for 3 hours, filter by suction, wash with deionized water, and dry to obtain epoxy silane coupling agent modified calcium ion exchange chemically etched talc powder.

[0040] Cerium Ion Exchange Chemically Etched Talc Powder Add 50 g of the cerium ion exchange chemically etched talc powder prepared in Preparation Example 2 into 1100 ml of 60% wt ethanol aqueous solution, then ultrasonically disperse it for 30 minutes at a power of 300 W, add 18 g of silane coupling agent KH-172, stir and react at 85 °C for 3 hours, filter by suction, wash with deionized water, and dry to obtain epoxy silane coupling agent modified cerium ion exchange chemically etched talc powder.

[0041] Lanthanum Ion Exchange Chemically Etched Talc Powder Add 50 g of the lanthanum ion exchange chemically etched talc powder prepared in Preparation Example 2 into 1100 ml of 60% wt ethanol aqueous solution, then ultrasonically disperse it for 30 minutes at a power of 300 W, add 18 g of silane coupling agent KH-172, stir and react at 85 °C for 3 hours, filter by suction, wash with deionized water, and dry to obtain epoxy silane coupling agent modified lanthanum ion exchange chemically etched talc powder.

[0042] Preparation Example 4: Epoxy Silane Coupling Agent Modified Chemically Etched Talc Powder Add 50 g of the chemically etched talc powder prepared in Preparation Example 2 into 1100 ml of 60% wt ethanol aqueous solution, then ultrasonically disperse it for 30 minutes at a power of 300 W, add 18 g of silane coupling agent KH-172, stir and react at 85 °C for 3 hours, filter by suction, wash with deionized water, and dry to obtain epoxy silane coupling agent modified chemically etched talc powder.

[0043] Preparation Example 5: Dopamine Modified Mica Iron Oxide Add 50 g of mica iron oxide with an average particle size of 10 μm into 800 ml of ethanol, ultrasonically wash it for 30 minutes at 300 W, filter, wash with deionized water, dry at 80 °C to obtain pretreated mica iron oxide. Then dissolve 2 g of dopamine hydrochloride in 1000 ml of Tris-HCl buffer solution, stir evenly, adjust the pH value to 8.5, stir and react at room temperature for 6 hours, centrifuge and separate, wash with deionized water, and vacuum dry at 60 °C to obtain dopamine modified mica iron oxide. Examples

[0044] Example 1 Component A: 35 g of epoxy resin, 2.5 g of n-butanol, 5 g of xylene, 0.5 g of dispersant, 10 g of iron oxide red, 6 g of heavy calcium carbonate, 2 g of zinc oxide, 6 g of anti-rust silicon powder, 4 g of kaolin, 1.3 g of calcium ion-exchanged talc powder prepared in Preparation Example 1, 1.3 g of cerium ion-exchanged talc powder prepared in Preparation Example 1, 1.3 g of lanthanum ion-exchanged talc powder prepared in Preparation Example 1, 7 g of anti-rust pigment, 15 g of precipitated barium sulfate, 4 g of petroleum resin, 0.06 g of leveling agent; Component B: 12 g of curing agent, 1 g of n-butanol, 1.5 g of xylene, 1 g of dispersant, 0.6 g of micaceous iron oxide.

[0045] Weigh the raw materials of Component A and Component B by mass parts respectively for standby. Mix epoxy resin, n-butanol and xylene, add the dispersant, stir at 200 r / min for 8 min, add iron oxide red and anti-rust pigment and disperse until there is no dry powder on the liquid surface, then stir at 800 r / min for 20 min, seal and soak for 1 h, and stir at 400 r / min for 10 min; add the remaining raw materials of Component A under the stirring state of 400 r / min, continue to stir for 10 min, and obtain Component A. Stir the raw materials of Component B at 400 r / min for 12 min, add them to Component A, and mix evenly to obtain an environment-friendly epoxy coating without phosphorus and with a salt spray resistance of 1000 h.

[0046] Example 2 Component A: 40 g of epoxy resin, 2 g of n-butanol, 5.5 g of xylene, 0.1 g of dispersant, 12 g of iron oxide red, 4 g of heavy calcium carbonate, 4 g of zinc oxide, 4 g of anti-rust silicon powder, 6 g of kaolin, 1 g of calcium ion-exchanged talc powder prepared in Preparation Example 1, 1 g of cerium ion-exchanged talc powder prepared in Preparation Example 1, 1 g of lanthanum ion-exchanged talc powder prepared in Preparation Example 1, 8 g of anti-rust pigment, 12 g of precipitated barium sulfate, 5 g of petroleum resin, 0.02 g of leveling agent; Component B: 15 g of curing agent, 2 g of n-butanol, 1 g of xylene, 3 g of dispersant, 0.4 g of micaceous iron oxide.

[0047] Weigh the raw materials of Component A and Component B by mass parts respectively for standby. Mix epoxy resin, n-butanol and xylene, add the dispersant, stir at 200 r / min for 8 min, add iron oxide red and anti-rust pigment and disperse until there is no dry powder on the liquid surface, then stir at 800 r / min for 20 min, seal and soak for 1 h, and stir at 400 r / min for 10 min; add the remaining raw materials of Component A under the stirring state of 400 r / min, continue to stir for 10 min, and obtain Component A. Stir the raw materials of Component B at 400 r / min for 12 min, add them to Component A, and mix evenly to obtain an environment-friendly epoxy coating without phosphorus and with a salt spray resistance of 1000 h.

[0048] Example 3 Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of rust-proof silicon powder, 5 g of kaolin, 1.2 g of calcium ion-exchanged talc powder prepared in Preparation Example 1, 1.2 g of cerium ion-exchanged talc powder prepared in Preparation Example 1, 1.2 g of lanthanum ion-exchanged talc powder prepared in Preparation Example 1, 7.5 g of rust-proof pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of micaceous iron oxide.

[0049] Weigh the raw materials of Component A and Component B by mass parts respectively for standby. Mix epoxy resin, n-butanol and xylene, add the dispersant, stir at 200 r / min for 8 min. After adding iron oxide red and rust-proof pigment and dispersing until there is no dry powder on the liquid surface, stir at 800 r / min for 20 min, seal and soak for 1 h, and stir at 400 r / min for 10 min; Add the remaining raw materials of Component A under the stirring state of 400 r / min, continue to stir for 10 min, and obtain Component A. Stir the raw materials of Component B at 400 r / min for 12 min, add them to Component A, and mix evenly to obtain an environment-friendly epoxy coating with 1000 h of phosphorus-free salt spray resistance.

[0050] Example 4 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of rust-proof silicon powder, 5 g of kaolin, 0.72 g of calcium ion-exchanged talc powder prepared in Preparation Example 1, 1.44 g of cerium ion-exchanged talc powder prepared in Preparation Example 1, 1.44 g of lanthanum ion-exchanged talc powder prepared in Preparation Example 1, 7.5 g of rust-proof pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of micaceous iron oxide.

[0051] Example 5 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of anti-rust silicon powder, 5 g of kaolin, 1.44 g of calcium ion-exchanged talc powder prepared in Preparation Example 1, 1.44 g of cerium ion-exchanged talc powder prepared in Preparation Example 1, 0.72 g of lanthanum ion-exchanged talc powder prepared in Preparation Example 1, 7.5 g of anti-rust pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of micaceous iron oxide.

[0052] Example 6 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of anti-rust silicon powder, 5 g of kaolin, 0.72 g of calcium ion-exchanged chemically etched talc powder prepared in Preparation Example 2, 1.44 g of cerium ion-exchanged chemically etched talc powder prepared in Preparation Example 2, 1.44 g of lanthanum ion-exchanged chemically etched talc powder prepared in Preparation Example 2, 7.5 g of anti-rust pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of micaceous iron oxide.

[0053] Example 7 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of anti-rust silicon powder, 5 g of kaolin, 0.72 g of epoxy group silane coupling agent modified calcium ion-exchanged chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified cerium ion-exchanged chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified lanthanum ion-exchanged chemically etched talc powder prepared in Preparation Example 3, 7.5 g of anti-rust pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of micaceous iron oxide.

[0054] Example 8 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of anti-rust silicon powder, 5 g of kaolin, 0.72 g of epoxy group silane coupling agent modified calcium ion exchange chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified cerium ion exchange chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified lanthanum ion exchange chemically etched talc powder prepared in Preparation Example 3, 7.5 g of anti-rust pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.5 g of dopamine modified mica iron oxide prepared in Preparation Example 4.

[0055] Example 9 The difference between this example and Example 3 is only that: Component A: 38 g of epoxy resin, 2.2 g of n-butanol, 5.2 g of xylene, 0.3 g of dispersant, 11 g of iron oxide red, 5 g of heavy calcium carbonate, 3 g of zinc oxide, 5 g of anti-rust silicon powder, 5 g of kaolin, 0.72 g of epoxy group silane coupling agent modified calcium ion exchange chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified cerium ion exchange chemically etched talc powder prepared in Preparation Example 3, 1.44 g of epoxy group silane coupling agent modified lanthanum ion exchange chemically etched talc powder prepared in Preparation Example 3, 7.5 g of anti-rust pigment, 13 g of precipitated barium sulfate, 4.5 g of petroleum resin, 0.04 g of leveling agent; Component B: 13.5 g of curing agent, 1.5 g of n-butanol, 1.2 g of xylene, 2 g of dispersant, 0.6 g of dopamine modified mica iron oxide prepared in Preparation Example 4.

[0056] Comparative Example Comparative Example 1 Component A: 35 g of epoxy resin, 2.5 g of n-butanol, 5 g of xylene, 0.5 g of dispersant, 10 g of iron oxide red, 6 g of heavy calcium carbonate, 2 g of zinc oxide, 6 g of anti-rust silicon powder, 4 g of kaolin, 3.9 g of calcium ion exchange talc powder prepared in Preparation Example 1, 7 g of anti-rust pigment, 15 g of precipitated barium sulfate, 4 g of petroleum resin, 0.06 g of leveling agent; Component B: 12 g of curing agent, 1 g of n-butanol, 1.5 g of xylene, 1 g of dispersant, 0.6 g of mica iron oxide.

[0057] Weigh the raw materials of Component A and Component B by mass parts respectively for standby. Mix epoxy resin, n-butanol, and xylene, add a dispersant, stir at 200 r / min for 8 min. After adding iron oxide red and anti-rust pigment and dispersing until there is no dry powder on the liquid surface, stir at 800 r / min for 20 min, seal and soak for 1 h, and then stir at 400 r / min for 10 min. Add the remaining raw materials of Component A under the stirring state of 400 r / min, continue to stir for 10 min to obtain Component A. Stir the raw materials of Component B at 400 r / min for 12 min, add them to Component A, and mix evenly to obtain an epoxy coating.

[0058] Comparative Example 2 Component A: 35 g of epoxy resin, 2.5 g of n-butanol, 5 g of xylene, 0.5 g of dispersant, 10 g of iron oxide red, 6 g of heavy calcium carbonate, 2 g of zinc oxide, 6 g of anti-rust silicon powder, 4 g of kaolin, 3.9 g of epoxy-based silane coupling agent-modified chemically etched talc powder prepared in Preparation Example 4, 7 g of anti-rust pigment, 15 g of precipitated barium sulfate, 4 g of petroleum resin, 0.06 g of leveling agent; Component B: 12 g of curing agent, 1 g of n-butanol, 1.5 g of xylene, 1 g of dispersant, 0.6 g of micaceous iron oxide.

[0059] Weigh the raw materials of Component A and Component B by mass parts respectively for standby. Mix epoxy resin, n-butanol, and xylene, add a dispersant, stir at 200 r / min for 8 min. After adding iron oxide red and anti-rust pigment and dispersing until there is no dry powder on the liquid surface, stir at 800 r / min for 20 min, seal and soak for 1 h, and then stir at 400 r / min for 10 min. Add the remaining raw materials of Component A under the stirring state of 400 r / min, continue to stir for 10 min to obtain Component A. Stir the raw materials of Component B at 400 r / min for 12 min, add them to Component A, and mix evenly to obtain an epoxy coating.

[0060] Performance detection test Coat the paint samples prepared in the examples and comparative examples on a steel plate, with a dry film thickness of 60 μm. After curing at room temperature for 24 hours, conduct the following detections: Refer to GB / T 10125 to detect the salt spray resistance of the paint; Refer to GB / T 1720 - 1979 to detect the adhesion grade of the paint; Refer to GB / T 1865 - 2009 (Cycle A) to detect the resistance to artificial weathering of the paint.

[0061] Summarize the test results in Table 1.

[0062] Table 1 Salt spray resistance (h) Adhesion grade Resistance to artificial weathering, 200h Example 1 1210 3 Qualified Example 2 1230 3 Qualified Example 3 1220 3 Qualified Example 4 1390 2 Qualified Example 5 1190 2 Qualified Example 6 1470 2 Qualified Example 7 1580 2 Qualified Example 8 1730 1 Qualified Example 9 1700 2 Qualified Comparative example 1 876 4 Unqualified Comparative example 2 801 3 Unqualified Combined with Examples 1-3 and Comparative Examples 1-2 and Table 1, it can be seen that in this application, by specifically defining the components and parts by mass of the coating mainly composed of epoxy resin, calcium ion-exchanged talc powder, cerium ion-exchanged talc powder, and lanthanum ion-exchanged talc powder are used together. By adding different raw materials in sequence and defining the stirring speed, the mixture can be stirred evenly without destroying the molecular structure, and the prepared coating has good salt spray resistance.

[0063] Combined with Examples 3-6 and Table 1, it can be seen that in this application, by first chemically etching the talc powder and defining the mass ratio of calcium ion-exchanged talc powder, cerium ion-exchanged talc powder, and lanthanum ion-exchanged talc powder, the stable salt spray resistance performance of the coating is further improved.

[0064] Combined with Example 3, Examples 7-9 and Table 1, it can be seen that in this application, by respectively modifying the ion-exchanged chemically etched talc powder with epoxy group silane coupling agent and modifying mica iron oxide with dopamine, it can be made more uniform and stable in the system. At the same time, by defining the epoxy value of epoxy resin, the amine value of curing agent, and the mass ratio of the four, the film tension is uniform after the modified filler participates in curing, the coating film is more dense and stable, and the protection effect is good.

[0065] This specific embodiment is only an interpretation of this application, and it does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. An environmentally friendly epoxy coating resistant to salt spray for 1000 h without phosphorus, characterized in that: It includes Component A and Component B; Component A includes the following raw materials in parts by weight: 35 - 40 parts of epoxy resin, 2 - 2.5 parts of n-butanol, 5 - 5.5 parts of xylene, 0.1 - 0.5 part of dispersant, 10 - 12 parts of iron oxide red, 4 - 6 parts of heavy calcium carbonate, 2 - 4 parts of zinc oxide, 4 - 6 parts of anti-rust silicon powder, 4 - 6 parts of kaolin, 3 - 4 parts of talc powder, 7 - 8 parts of anti-rust pigment, 12 - 15 parts of precipitated barium sulfate, 4 - 5 parts of petroleum resin, 0.02 - 0.06 part of leveling agent; Component B includes the following raw materials in parts by weight: 12 - 15 parts of curing agent, 1 - 2 parts of n-butanol, 1 - 1.5 parts of xylene, 1 - 3 parts of dispersant, 0.4 - 0.6 part of micaceous iron oxide; The talc powder includes one or more of calcium ion-exchanged talc powder, cerium ion-exchanged talc powder, and lanthanum ion-exchanged talc powder.

2. The phosphorus-free and salt spray resistant environmental protection epoxy coating according to claim 1 for 1000 hours, characterized in that: The talc powder includes calcium ion-exchanged talc powder, cerium ion-exchanged talc powder, and lanthanum ion-exchanged talc powder, and the mass ratio is 1:(1.5 - 2.5):(2 - 2.1).

3. The environmentally friendly epoxy coating without phosphorus and resistant to salt spray for 1000 h according to claim 1, characterized in that: The talc powder is chemically etched talc powder, and the etching steps include: adding talc powder to a mixed solution of hydrofluoric acid and hydrochloric acid, stirring, filtering, washing, and drying to obtain chemically etched talc powder.

4. The environmentally friendly epoxy coating without phosphorus and resistant to salt spray for 1000 h according to claim 1, characterized in that: The talc powder is also modified with an epoxy group silane coupling agent.

5. The solvent-free heat and humidity resistant polyaspartate ester coating according to claim 4, characterized in that: The micaceous iron oxide includes dopamine-modified micaceous iron oxide, and the preparation steps include: adding micaceous iron oxide to a dopamine hydrochloride solution, stirring evenly, adjusting the pH value, adding a silane coupling agent, heating and reacting to obtain dopamine-modified micaceous iron oxide.

6. The environmentally friendly epoxy coating without phosphorus and resistant to salt spray for 1000 h according to claim 5, characterized in that: The epoxy equivalent of the epoxy resin is 400 - 500 eq / 100g, the curing agent is an amine curing agent, and the amine value is 500 - 600 mgKOH / g.

7. The environmentally friendly epoxy coating resistant to salt spray for 1000 h without phosphorus according to claim 6, characterized in that: The mass ratio of the epoxy resin, curing agent, talc powder, and dopamine-modified micaceous iron oxide is 35 - 40:12 - 15:3 - 4:0.

5.

8. The environmentally friendly epoxy coating without phosphorus and resistant to salt spray for 1000h according to claim 1, characterized in that: The average particle size of the micaceous iron oxide is 5 - 20 μm.

9. A method for preparing an environmentally friendly epoxy coating without phosphorus and resistant to salt spray for 1000 h according to any one of claims 1-8, characterized in that: It includes the following steps: Weigh the raw materials of Component A and Component B separately according to the parts by weight for standby. Mix the epoxy resin, n-butanol, and xylene, add the dispersant, stir at a low speed for 5 - 10 min, add the iron oxide red and anti-rust pigment and disperse until there is no dry powder on the liquid surface, then stir at a high speed for 25 - 35 min, seal and soak for 1 - 1.5 hours, and stir at a high speed for 10 - 15 min; Add the remaining raw materials of Component A under medium-speed stirring, continue to stir for 5 - 10 min to obtain Component A. Stir the raw materials of Component B at a medium speed for 10 - 15 min, add them to Component A, and mix evenly to obtain an environmentally friendly epoxy coating with 1000h salt spray resistance without phosphorus.

10. The preparation method of the phosphorus-free and salt spray resistant environmental protection epoxy coating for 1000h according to claim 9, characterized in that: The low-speed stirring speed is 50 - 300 r / min, the medium-speed stirring speed is 350 - 450 r / min, and the high-speed stirring speed is 500 - 1000 r / min.