Coating structure of rust removal and rust prevention paint and construction process of coating structure

Abstract

According to the coating structure of the rust removal and rust prevention coating and the construction technology of the coating structure, a three-layer rust removal and rust prevention structure is formed through an iron rust conversion layer, a primer layer and a finish paint layer, and the mechanical strength, the abrasion resistance and the rust prevention performance of a coating system are further improved; chemical bonding is formed among the primer layer, the rust conversion layer and the finish paint layer, so that the adhesive force of the coating is remarkably improved; the finishing coat layer has hydrophobicity and ultraviolet resistance which are changed step by step, so that the service life of the coating is prolonged; the whole coating gradually changes from the functions of conversion, rust prevention to mechanical protection from inside to outside, and has a good synergistic protection effect. The coating has low construction viscosity and good leveling property, adapts to various construction conditions, is simple and convenient to operate, is compact and flat in coating film, can be widely applied to the fields of bridges, ships, petrochemical equipment and the like, remarkably prolongs the service life of a metal structure, and reduces the maintenance and replacement cost.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based coatings, and in particular relates to a coating structure of a rust-removing and rust-preventing coating and a construction process thereof. Background Art

[0002] The wide application of metal materials in the fields of industry, construction, shipbuilding, automobiles, etc. has greatly promoted the development of modern industry. However, due to the long-term exposure of metal materials to the environment, they are corroded by oxygen, moisture, salt and other corrosive media, which makes them very susceptible to rust, resulting in the degradation of structural performance and shortened service life. Therefore, the development and application of anti-rust primers are crucial in the protection of metal materials.

[0003] At present, there are many defects in the protection measures for rusted metal surfaces. Common methods such as using rust converters alone or directly applying anti-rust paints are often ineffective; using only rust converters is difficult to provide long-term protection, and the conversion depth is insufficient, affecting the stability of the substrate; the anti-rust paint has insufficient adhesion to the conversion layer, resulting in peeling, which limits the protection effect. The coating structure is single and it is difficult to meet the corrosion requirements of different metal substrates and environments.

[0004] Therefore, there is an urgent need for a coating structure that has efficient rust conversion, excellent adhesion, weather resistance and waterproof performance. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide an epoxy metal primer and a preparation method and application thereof.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a coating structure of a rust-removing and rust-preventing coating, which comprises, from the inside to the outside, a metal base layer; and

[0009] A rust conversion layer coated on the metal base layer, a primer layer coated on the rust conversion layer, and a topcoat layer coated on the primer layer.

[0010] As a preferred solution of the coating structure of the rust removing and rust preventing coating of the present invention, the metal base layer is a metal material that is susceptible to oxidation corrosion in a conventional atmospheric environment.

[0011] As a preferred solution of the coating structure of the rust removing and anti-rust coating of the present invention, the primer layer is an epoxy metal primer layer.

[0012] As a preferred solution of the coating structure of the rust removing and rust preventing coating of the present invention, the topcoat layer is a two-component polyurethane topcoat layer.

[0013] As a preferred solution of the coating structure of the rust removing and rust preventing coating of the present invention, the thickness of the rust conversion layer is 20-30 μm, the thickness of the primer layer is 40-50 μm, and the thickness of the topcoat layer is 30-40 μm.

[0014] Another object of the present invention is to overcome the deficiencies in the prior art and provide a coating construction process.

[0015] In order to solve the above technical problems, the present invention provides the following technical solutions: a coating construction process, comprising:

[0016] Cleaning the surface of the metal base layer to remove loose rust;

[0017] Applying a rust conversion agent to form a rust conversion layer of 20-30 μm after drying;

[0018] Applying epoxy metal primer to ensure that the primer layer (300) is fully bonded to the rust conversion layer;

[0019] Two-component polyurethane topcoat applied for protection.

[0020] As a preferred solution of the coating construction process of the present invention, the rust conversion layer is constructed by brushing to increase the penetration depth of the conversion agent.

[0021] As a preferred solution of the coating construction process of the present invention, the primer layer is constructed by spraying to ensure uniform distribution.

[0022] As a preferred solution of the coating construction process of the present invention, the topcoat layer is sprayed to make the surface thickness uniform, so as to improve the hydrophobicity and surface smoothness of the coating.

[0023] As a preferred solution of the coating construction process of the present invention, the thicknesses of the rust conversion layer, the primer layer and the paint layer are adjusted according to the different materials of the metal base layer to achieve an optimized functional gradient.

[0024] Beneficial effects of the present invention: by introducing a rust conversion agent, efficient conversion of metal surface rust is achieved, and a three-layer structure of a rust conversion layer, a primer layer, and a topcoat layer is formed on the metal base layer together with an epoxy primer and a two-component polyurethane topcoat, further improving the mechanical strength, wear resistance, and rust resistance of the coating system; the coating as a whole has a good synergistic protective effect. The present invention has a low construction viscosity and good leveling properties, is adaptable to a variety of construction conditions, is easy to operate, and has a dense and smooth coating film. It can be widely used in bridges, ships, petrochemical equipment, and other fields, significantly extending the service life of metal structures and reducing maintenance and replacement costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a schematic diagram of the coating structure of the present invention. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0030] Example 1

[0031] Reference Figure 1 This embodiment provides a coating structure of a rust removing and anti-rust coating, a metal base layer 100, a rust conversion layer 200 coated on the metal base layer 100, a primer layer 300 coated on the rust conversion layer 200, and a topcoat layer 400 coated on the primer layer 300, wherein the metal base layer 100 is a metal material that is susceptible to oxidative corrosion in a conventional atmospheric environment.

[0032] Furthermore, the primer layer 300 is an epoxy metal primer layer, the topcoat layer 400 is a two-component polyurethane topcoat layer, the thickness of the rust conversion layer 200 is 20-30 μm, the thickness of the primer layer 300 is 40-50 μm, and the thickness of the topcoat layer 400 is 30-40 μm.

[0033] Preferably, the thickness of the rust conversion layer 200 is 20-30 μm, the thickness of the primer layer 300 is 40-50 μm, and the thickness of the topcoat layer 400 is 30-40 μm. The overall rust removal and rust prevention coating can have a good effect. The three-layer structure cooperates with each other to effectively extend the service life of the metal material and significantly improve the rust prevention performance and environmental adaptability.

[0034] Example 2

[0035] Reference Figure 1 , provides a construction process for a rust-removing and rust-proofing coating, including cleaning the surface of a metal base layer 100 to remove loose rust;

[0036] Applying a rust conversion agent to form a rust conversion layer 200 of 20-30 μm after drying;

[0037] Applying epoxy metal primer to ensure that the primer layer 300 is fully combined with the rust conversion layer 200;

[0038] Two-component polyurethane topcoat applied for protection.

[0039] Specifically, the rust conversion layer 200 is constructed by brushing to increase the penetration depth of the conversion agent, the primer layer 300 is constructed by spraying to ensure uniform distribution, and the topcoat layer 400 is sprayed to improve the hydrophobicity and surface smoothness of the coating. The thickness of the rust conversion layer 200, the primer layer 300 and the topcoat layer 400 are adjusted according to the material of the metal base layer to achieve an optimized functional gradient.

[0040] Specifically, the main components of the rust converter are organic carboxylic acids, phosphoric acid and its salts, etc. Its working principle is to use the active ingredients therein to contact the metal surface with ferric oxide (Fe2O3 red rust) and ferric oxide (Fe3O4 blue oxide scale). Through the chemical conversion phase film corrosion inhibition mechanism, the rust and oxide scale are naturally converted after 0.5-1 hour at room temperature to form a tight bright gray-black anti-rust film layer, blocking the metal from contacting oxygen and water vapor in the atmosphere, etc., and slowing down the oxidation process of the metal. The main function of the rust converter is to chemically react with the iron oxide (rust) on the metal surface to form a dense, non-destructible protective layer (passivation film), which can isolate air and moisture, thereby preventing iron from undergoing oxidation reactions when in contact with air and moisture to form new rust.

[0041] The reaction mechanism is: Fe2 O 3 +2R-COOH→Fe(R-COO) 2 +H 2 O

[0042] Furthermore, the key ingredients in the epoxy metal primer include epoxy emulsion (modified macromolecular epoxy resin), composite anti-rust pigment (zinc phosphate and aluminum tripolyphosphate), dispersant (modified styrene maleic anhydride copolymer), anti-flash rust agent (water-based anti-flash rust agent), etc., which provide strong water resistance, salt spray resistance, etc.

[0043] Specifically, during construction, there are micron-scale concave-convex structures on the surface of the rust conversion layer 200 after curing. These microstructures provide more interlocking sites for the epoxy primer coating. When painting, the epoxy primer can partially penetrate into the pores of the rust conversion layer 200. After the metal primer is cured, a physical interlocking is formed, which enhances the mechanical adhesion of the coating. In addition, the high cross-linking density polymer network formed after the epoxy metal primer is cured can provide effective mechanical support for the rust conversion layer 200 to prevent the coating from cracking or peeling.

[0044] Furthermore, after the epoxy metal primer is cured, a two-component polyurethane topcoat is sprayed to form a topcoat layer 400, which has excellent weather resistance and chemical stability, further enhancing the barrier effect against ultraviolet rays, moisture and corrosive substances, and better providing protection for the metal surface, making it more rust-resistant.

[0045] The coating system of the present invention adopts a multi-layer structure combination design of a rust converter, an epoxy metal primer, and a two-component polyurethane topcoat. Through the scientifically optimized multi-layer synergistic effect, the rust converter converts the loose rust on the metal surface into a dense passivation film, fills the microscopic pores and forms a rough surface, reduces the occurrence of subsequent rust, and enhances the adhesion of the subsequent coating; the epoxy metal primer penetrates and embeds the microporous structure, produces a mechanical lock with its surface, forms a stable primer layer 300, provides excellent adhesion and corrosion resistance, and finally the two-component polyurethane topcoat is interlocked with the microporous structure on the surface of the epoxy primer, so that it is more closely combined with the epoxy metal primer, improves the stability, mechanical strength and aesthetics of the overall coating, and finally forms a multi-layer protection system from the inside to the outside. The multi-layer shielding superposition makes it difficult for corrosive media to penetrate the entire coating system, thereby significantly extending the anti-rust life of the metal, and has excellent resistance to high salt fog and high humidity environments. The overall system achieves high bonding between the layers of the coating through physical locking, and enhances the anti-peeling performance.

[0046] It should be noted that in the prior art, separate rust converters or anti-rust primers are mostly used for short-term protection, while the present invention achieves a balance between long-term corrosion resistance and mechanical strength through scientific combination. It not only has the functions of rust removal, rust prevention, and long-term protection, but also has excellent adhesion and mechanical properties, which significantly improves the overall performance of the coating, breaks through the limitations of the prior art, and provides a new solution for metal surface protection.

[0047] Example 3

[0048] This embodiment is based on the previous two embodiments, and is directed to the coating construction of the low-carbon steel weld area as the metal base layer 100, and verifies various properties of the coating structure.

[0049] Construction steps:

[0050] 1. Surface pretreatment: Use a wire brush to remove loose rust and retain a stable rust layer.

[0051] 2. Rust conversion layer: Use a phosphate-based rust converter to brush and form a 25μm rust conversion layer. The penetration depth of the conversion layer is about 10μm, which effectively converts iron oxide into stable iron phosphate.

[0052] 3. Primer layer: Spray epoxy primer with a thickness of 50μm.

[0053] 4. Topcoat layer: Spray two-component polyurethane topcoat with a thickness of 35μm.

[0054] The test results are shown in Table 1 below:

[0055] Table 1 Performance test of rust removal and anti-rust paint and coating on low carbon steel weld area

[0056] Test items Test Results Salt spray test 930h Adhesion Level 0 Water resistance 500h

[0057] Example 4

[0058] This embodiment is based on Embodiment 1 and Embodiment 2, and is directed to the coating construction of a low-carbon steel pipe as the metal base layer 100 .

[0059] Base material: Construction steps:

[0060] 1. Surface pretreatment: Mechanical grinding to remove loose rust and clean the surface.

[0061] 2. Rust conversion layer: Apply rust conversion agent with a thickness of 30μm, and form a uniform protective layer after drying.

[0062] 3. Epoxy primer layer: spray epoxy metal primer with a thickness of 50μm.

[0063] 4. Double polyurethane topcoat layer: spray polyurethane topcoat with a thickness of 40μm.

[0064] The test results are shown in Table 2 below:

[0065] Table 2 Performance test of rust removal and anti-rust paint and coating on low carbon steel pipe

[0066] Test items Test Results Salt spray test 1020h Adhesion Level 0 Water resistance 520h

[0067] Example 5

[0068] This embodiment is based on Embodiment 1 and Embodiment 2, and is directed to the coating construction of color steel tiles as the metal base layer 100 .

[0069] Construction steps:

[0070] 1. Surface pretreatment: clean the surface.

[0071] 2. Rust conversion layer: Apply rust conversion agent with a thickness of 25μm, and form a protective layer after drying.

[0072] 3. Epoxy primer layer: spray 40μm modified epoxy primer.

[0073] 4. Two-component polyurethane topcoat layer: spray polyurethane topcoat with a thickness of 35μm.

[0074] The test results are shown in Table 3 below:

[0075] Table 3 Performance test of rust removal and anti-rust paint and coating on color steel tiles

[0076] Test items Test Results Salt spray test 1100h Adhesion Level 0 Water resistance 550h

[0077] It can be seen from Examples 3-5 that the rust removing and rust preventing coating and coating mechanism thereof provided by the present invention have good rust removing and rust preventing functions on rust at different positions and on different substrates, and can play a good protective role.

[0078] Example 6

[0079] This embodiment is based on Embodiment 1 and Embodiment 2, and uses steel plates as coatings for different types of corrosion conditions on the same metal substrate 100.

[0080] A: Surface rust, loose structure

[0081] Construction steps:

[0082] Surface preparation: Remove loose rust.

[0083] Construction of rust conversion layer: Brush rust conversion agent with a thickness of 25μm.

[0084] Epoxy primer layer construction: spray 40μm epoxy primer.

[0085] Two-component polyurethane topcoat construction: spray 35μm polyurethane topcoat.

[0086] B: Dense rust on the surface, heavy and difficult to remove

[0087] Construction steps:

[0088] Surface pretreatment: Use high-pressure sandblasting to remove loose rust and retain dense rust.

[0089] Construction of rust conversion layer: Brush rust conversion agent with a thickness of 30μm.

[0090] Epoxy primer layer construction: Apply 50μm thick epoxy primer to enhance the adhesion performance of the dense layer.

[0091] Two-component polyurethane topcoat construction: Spray 40μm polyurethane topcoat to improve overall protection performance.

[0092] Table 4 Performance test of group A and group B

[0093] Test items Test results (A) Test results (B) Salt spray test 1100h 980h Adhesion Level 0 Level 0 Water resistance 540h 510h

[0094] From the above, it can be seen that under different corrosion conditions, the paint and coating structure invented by us, combined with the corresponding coating thickness, can still play a good protective effect.

[0095] Example 7

[0096] This embodiment is based on the previous embodiments and designs a comparative test between a gradient functional coating and a homogeneous coating to demonstrate the differences in adhesion, corrosion resistance and comprehensive protective performance between the functional gradient coating and the traditional homogeneous coating.

[0097] Verify the multi-layer synergistic effect of the functional gradient coating (rust conversion layer 200, primer layer 300, topcoat layer 400) and the performance difference of the homogeneous coating (single epoxy metal primer) on different metal substrates.

[0098] Experimental design:

[0099] 1. Sample

[0100] Sample A (gradient coating): adopts the three-layer gradient structure of the present invention (rust conversion agent, epoxy primer, polyurethane topcoat).

[0101] Sample B (homogeneous coating): a single epoxy metal primer with a thickness of 100 μm was used.

[0102] 2. Base material: low carbon steel pipe.

[0103] The experimental data are shown in Table 5 below.

[0104] Table 5 Performance comparison test between functional gradient coating and traditional homogeneous coating

[0105] Test items Sample A (gradient coating) Sample B (homogeneous coating) Salt spray test 1100h 580h Adhesion Level 0 Level 0 Water resistance (48h) No blistering, no peeling No blistering, no peeling Weather resistance (72h) No discoloration, no cracks Discoloration and micro-cracks Flash rust inhibition (high humidity) normal Rust spots appear

[0106] In summary, due to the design of the gradient functional coating, each layer of coating achieves synergistic effects in different functions:

[0107] The rust converter converts the loose rust on the metal surface into a dense passivation film, filling the microscopic pores and forming a rough surface, reducing the occurrence of subsequent rust and enhancing the adhesion of subsequent coatings; the epoxy metal primer penetrates and embeds into the microporous structure of the passivation layer, mechanically locking with its surface to form a stable base coating, providing excellent adhesion and corrosion resistance. Finally, the two-component polyurethane topcoat is interlocked with the microporous structure of the surface of the cured epoxy primer, making it more closely bonded with the epoxy metal primer, improving the stability, mechanical strength and aesthetics of the overall coating, and ultimately forming a multi-layer protection system from the inside out.

[0108] However, homogeneous coatings lack stratification function and have uneven stress distribution inside the coating, making them prone to failure in high humidity or salt spray environments.

[0109] In summary, the present invention achieves multifunctional coordinated optimization through multi-layer gradient design, significantly improves the comprehensive performance of the coating, and has significant innovation and industrial application value.

[0110] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A coating structure of a rust-removing and rust-preventing coating, characterized in that: From inside to outside, it includes: a metal base layer (100); and A rust conversion layer (200) coated on the metal base layer (100), a primer layer (300) coated on the rust conversion layer (200), and a topcoat layer (400) coated on the primer layer (300).

2. The coating structure of a rust-removing and rust-preventing coating as claimed in claim 1, characterized in that: The metal base layer (100) is a metal material that is susceptible to oxidation corrosion in a conventional atmospheric environment.

3. The coating structure of a rust-removing and rust-preventing paint according to claim 2, characterized in that: The primer layer (300) is an epoxy metal primer layer.

4. The coating structure of a rust-removing and rust-preventing paint according to claim 3, characterized in that: The topcoat layer (400) is a two-component polyurethane topcoat layer.

5. The coating structure of a rust-removing and rust-preventing paint according to claim 4, characterized in that: The thickness of the rust conversion layer (200) is 20-30 μm, the thickness of the primer layer (300) is 40-50 μm, and the thickness of the topcoat layer (400) is 30-40 μm.

6. A coating construction process, characterized in that: A coating structure comprising the rust-removing and rust-preventing coating according to any one of claims 1 to 5; and the following construction steps: Cleaning the surface of the metal base layer (100) to remove loose rust; Applying a rust conversion agent to form a rust conversion layer (200) of 20-30 μm after drying; Applying epoxy metal primer to ensure that the primer layer (300) is fully bonded to the rust conversion layer (200); Two-component polyurethane topcoat applied for protection.

7. A coating construction process as claimed in claim 6, characterized in that: The rust conversion layer (200) is constructed by brushing to increase the penetration depth of the conversion agent.

8. A coating construction process as claimed in claim 6, characterized in that: The primer layer (300) is applied by spraying to ensure uniform distribution.

9. A coating construction process as claimed in claim 6, characterized in that: The topcoat layer (400) is sprayed to improve the hydrophobicity and surface smoothness of the coating.

10. A coating construction process as claimed in claim 6, characterized in that: The thicknesses of the rust conversion layer, the primer layer and the paint layer are adjusted according to the material of the metal base layer to achieve an optimized functional gradient.

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