Anticorrosion treatment process for dry cargo container

Abstract

The invention discloses an anti-corrosion treatment process for a dry cargo container, which comprises the following steps: (1) degreasing and dedusting the surface of a container plate to remove oil stains, dust and impurities on the surface of the container plate and ensure the cleanliness of the surface of the container plate; (2) the surface of the container plate is coated with a pre-primer combination reagent, the coating amount is 0.02-0.05 L / m, and a compact transition combination layer is formed on the surface of the container plate; (3) cutting, bending, welding and assembling the container plate to obtain a dry cargo container; and (4) finishing paint is sprayed on the surface of the dry cargo container, the spraying amount is 0.1-1.0 L / m, and drying is conducted after spraying is completed. By optimizing the anticorrosion system composition and the construction process, the construction operation is simplified, the production and environmental protection cost is reduced, the carbon emission is reduced, and meanwhile, the anticorrosion performance of the container is guaranteed and even improved. The dry cargo container is excellent in corrosion resistance and long in service life.

Description

Technical Field

[0001] This invention relates to the field of container anti-corrosion treatment technology, and more specifically to an anti-corrosion treatment process for dry cargo containers. Background Technology

[0002] As the core carrier of cargo transportation, dry cargo containers are exposed to complex and harsh environments such as marine salt spray, industrial dust, and diurnal temperature variations for extended periods. Therefore, corrosion resistance is a key indicator determining their service life and transportation safety. Current technologies generally employ a multi-layered composite anti-corrosion system for dry cargo containers, consisting of weathering steel plate + sandblasting + workshop zinc powder primer + secondary sandblasting + secondary zinc powder primer + intermediate coat + topcoat. While this system can meet corrosion requirements to a certain extent, it has many inherent defects.

[0003] First, the construction process is complicated and the chain of procedures is long. The system requires the sequential completion of several core processes, such as surface pretreatment of weathering steel plates, zinc powder primer spraying and curing, intermediate paint spraying and curing, and topcoat spraying and curing. Auxiliary operations such as grinding, dust removal, and drying are also required between each process. This not only places strict requirements on the temperature, humidity, and cleanliness of the construction environment, but also significantly extends the production cycle.

[0004] Secondly, costs remain high. On the one hand, the procurement costs of various coatings such as zinc powder primer, intermediate coat, and topcoat are high, and the coating loss rate is usually as high as 50%. On the other hand, multi-process operations require a large number of professional construction workers, resulting in a high proportion of labor costs. At the same time, the multiple spraying and curing processes consume a lot of energy, further increasing production costs.

[0005] More importantly, existing processes are not environmentally friendly. Zinc powder particles in zinc-based primers easily generate dust pollution during spraying, and large amounts of VOCs (volatile organic compounds) are released during paint thinner and curing. These pollutants not only harm the health of operators but also exacerbate air pollution. Furthermore, the energy consumption of multiple processes leads to high carbon emissions in container production, contradicting the current global advocacy for "dual carbon" goals.

[0006] Therefore, how to develop a corrosion protection process for dry cargo containers that is simple to construct, low in cost, environmentally friendly, and has excellent corrosion resistance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to provide an anti-corrosion treatment process for dry cargo containers. By optimizing the composition of the anti-corrosion system and the construction process, it simplifies construction operations, reduces production and environmental protection costs, and reduces carbon emissions, while ensuring or even improving the anti-corrosion performance of the containers.

[0008] Therefore, the present invention provides an anti-corrosion treatment process for dry cargo containers, comprising: (1) Degrease and dust removal treatment is carried out on the surface of the container plates to remove oil, dust and impurities from the surface of the container plates and ensure the cleanliness of the container plate surface. (2) A pre-base bonding agent is coated on the surface of the container plate, with a coating amount of 0.02-0.05 L / m², so that a dense transition bonding layer is formed on the surface of the container plate; (3) The container plates are cut, bent, welded and assembled to obtain a dry cargo container; (4) Apply a topcoat to the surface of the dry cargo container, with a coating amount of 0.1-1.0 L / m², and then dry it after the coating is completed.

[0009] Preferably, in step (1), the surface of the container plate is coated with a zinc-aluminum-magnesium coating, the thickness of which is 80-120 g / m². 2 .

[0010] Preferably, in step (1), the weight percentages of each component in the zinc-aluminum-magnesium coating are: Al 5-12%, Mg 1-6%, Zn 76-95%.

[0011] Preferably, step (1), the degreasing and dust removal process includes: using an alkaline degreasing agent, treating at 40-50℃ for 3-5 minutes, then rinsing with clean water and drying; the dust removal process adopts a combination of high-pressure airflow blowing and vacuum dust collection.

[0012] Preferably, in step (2), the pre-base integration reagent comprises the following components in parts by weight: 5-10 parts of silane, 15-25 parts of resin, 3-5 parts of corrosion inhibitor, 2-4 parts of adhesion promoter, and 2-4 parts of film-forming aid.

[0013] Preferably, the corrosion inhibitor comprises sodium phytate and chitosan, wherein the mass ratio of sodium phytate to chitosan is 3-5:1.

[0014] Preferably, the film-forming aid comprises propylene glycol methyl ether acetate.

[0015] Preferably, the adhesion promoter comprises an epoxy phosphate compound and an epoxy silane coupling agent, wherein the mass ratio of the epoxy phosphate compound to the epoxy silane coupling agent is 2:1-3:1.

[0016] Preferably, in step (4), the drying temperature is 65-85℃ and the drying time is 1-2h.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are: This invention significantly simplifies the construction process and reduces construction difficulty: It eliminates the cumbersome zinc powder primer and intermediate coat spraying and curing steps in existing processes. The core anti-corrosion treatment only requires two key operations: pre-primer and topcoat application and drying. This reduces the construction steps by more than 60%. Furthermore, the pre-primer and topcoat can be naturally air-dried after application, eliminating the need for additional curing equipment. The topcoat only requires one drying cycle, significantly reducing the requirements for the construction environment. Ordinary production workshops can meet the operating conditions, greatly improving construction efficiency and shortening the production cycle.

[0018] Significantly reduces production and labor costs: On the one hand, this invention eliminates the use of zinc powder primer and intermediate coat, requiring only pre-primer and topcoat, reducing paint procurement costs by 60%. Furthermore, the pre-primer requires less coating and has a low wastage rate, further controlling material costs. On the other hand, the simplified construction process reduces the number of operators required by more than 50%, significantly lowering labor costs. In addition, a single drying operation reduces energy consumption by more than 50% compared to the multiple curing processes in existing technologies, further compressing production costs.

[0019] Reduce environmental pollutant emissions and lower carbon emissions: The pre-primer-combination reagent used in this invention is an aqueous system, which reduces VOC emissions by more than 95% compared to traditional zinc powder primers, and there is no zinc powder dust pollution; at the same time, the simplified construction process reduces energy consumption, reducing the carbon emissions of paint in the container production process by 65%, which meets environmental protection requirements and the "dual carbon" target, and has good environmental benefits.

[0020] This invention achieves a performance breakthrough through a synergistic anti-corrosion system of "zinc-aluminum-magnesium coated plate + pre-base integrated reagent + topcoat". One of its core innovations lies in the highly efficient interface bonding mechanism between the zinc-aluminum-magnesium coating and the pre-base integrated reagent: Unlike the traditional approach of multi-layer coatings that achieve protection solely through physical stacking, this invention utilizes the dual reactivity of silane to construct a stable chemical covalent bond between the zinc-aluminum-magnesium coating and the pre-base integrated reagent. Combined with the complexation strengthening and hydrogen bonding effects of the corrosion inhibitor, the interface bonding strength is increased by more than 60%, completely solving industry pain points such as interface peeling and blistering that are prone to occur in traditional coatings. At the same time, the resulting "chemical anchoring + physical coating" composite transition bonding layer not only possesses excellent corrosion media barrier capabilities but also provides a good adhesion substrate for the subsequent topcoat, enabling a tight intermolecular force to form between the topcoat and the transition layer. Furthermore, the Zn-Al / MgZn2 ternary eutectic structure of the zinc-aluminum-magnesium coated plate provides excellent sacrificial anodic protection (reducing corrosion current density by an order of magnitude compared to traditional weathering steel plates). Combined with the weather resistance and anti-aging properties of the high-performance polyurethane topcoat, these three elements form a complementary and synergistic anti-corrosion system of "sacrificial anodic protection - chemical interface barrier - surface weathering protection." The overall corrosion resistance far exceeds that of the existing "zinc powder primer + intermediate coat + topcoat" system, with salt spray corrosion tolerance exceeding 3000 hours, extending the service life of dry cargo containers to 15-20 years. This invention achieves a dual breakthrough of "simplifying the coating structure" and "improving anti-corrosion performance" through innovative interface bonding mechanisms, demonstrating significant technological innovation. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments.

[0022] This invention discloses an anti-corrosion treatment process for dry cargo containers, comprising the following steps: (1) Degrease and dust removal treatment is carried out on the surface of the container plates to remove oil, dust and impurities from the surface of the container plates and ensure the cleanliness of the container plate surface. The container plates can be any type of container plate commonly used in this technical field, such as metal container plates, and no specific restrictions are imposed here.

[0023] The container panels are coated with a zinc-aluminum-magnesium oxide (ZAMC) coating, with a thickness of 80-120 g / m². 2 Within this thickness range, the zinc-aluminum-magnesium coating can provide direct and effective anti-corrosion protection to the surface of the container panels.

[0024] The weight percentages of each component in the zinc-aluminum-magnesium coating are: Al 5-12%, Mg 1-6%, and Zn 76-95%, which ensures that the zinc-aluminum-magnesium coating provides direct and effective anti-corrosion protection to the surface of container plates.

[0025] In some embodiments of the present invention, the process of degreasing and dust removal of the container plate surface includes: using an alkaline degreasing agent to treat the container plate surface at 40℃-50℃ for 3-5 minutes, then rinsing the container plate surface with clean water and drying it.

[0026] The alkaline degreasing agent can be any alkaline degreasing agent commonly used in this technical field, and no specific limitations are made here.

[0027] In some embodiments of the present invention, the dust removal process adopts a combination of high-pressure airflow purging and vacuum dust collection, or a dust removal method commonly used in this technical field, and no specific limitation is made here.

[0028] (2) A pre-base bonding agent is coated on the surface of the container plate, with a coating amount of 0.02-0.05 L / m², so that a dense transition bonding layer is formed on the zinc-aluminum-magnesium coating on the surface of the container plate.

[0029] The pre-primer-integrated reagent used in this invention is an aqueous system, which reduces VOC emissions by more than 95% compared to traditional zinc powder primers and eliminates zinc powder dust pollution. At the same time, the simplified construction process of this invention reduces energy consumption and reduces carbon emissions from paint during container production by 65%, meeting environmental protection requirements and the "dual carbon" target, and has good environmental benefits.

[0030] The coating amount of the pre-base bonding agent can be 0.02-0.05 L / m², which can ensure that the pre-base bonding agent is evenly and effectively coated on the zinc-aluminum-magnesium coating on the surface of the container plate, and ensure that the pre-base bonding agent forms a dense transition bonding layer on the zinc-aluminum-magnesium coating on the surface of the container plate.

[0031] In some embodiments of the present invention, the pre-base bonding agent comprises the following components in parts by weight: 5-10 parts of silane, 15-25 parts of resin, 3-5 parts of corrosion inhibitor, 2-4 parts of adhesion promoter, and 2-4 parts of film-forming aid. The above components work together synergistically to ensure that the pre-base bonding agent is uniformly and effectively coated on the zinc-aluminum-magnesium coating on the surface of the container plate, thereby ensuring that the pre-base bonding agent forms a dense transition bonding layer on the zinc-aluminum-magnesium coating on the surface of the container plate.

[0032] In some embodiments of the present invention, the resin may include epoxy resin and / or acrylic polyurethane.

[0033] In some embodiments of the present invention, the corrosion inhibitor includes sodium phytate and chitosan, wherein the mass ratio of sodium phytate to chitosan is 3-5:1.

[0034] In some embodiments of the present invention, the film-forming aid includes propylene glycol methyl ether acetate.

[0035] In some embodiments of the present invention, the adhesion promoter includes an epoxy phosphate compound and an epoxy silane coupling agent, wherein the mass ratio of the epoxy phosphate compound and the epoxy silane coupling agent is 2:1-3:1.

[0036] The specific binding mechanism of the zinc-aluminum-magnesium coating and the pre-base integration reagent of the present invention is as follows: Due to the adsorption of water vapor in the atmosphere and its own oxidation, a large number of hydroxyl (-OH) active sites are naturally formed on the surface of the zinc-aluminum-magnesium coating. These hydroxyl (-OH) active sites provide the basis for interfacial chemical bonding. As the core coupling component, the alkoxy (-OR) in the molecular structure of silane first undergoes a hydrolysis reaction in an aqueous environment to generate an active intermediate containing silanol (-Si-OH). This intermediate rapidly diffuses to the surface of the zinc-aluminum-magnesium coating and undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the zinc-aluminum-magnesium coating to form a stable Si-O-Me (Me is Zn, Al, Mg metal ions) covalent chemical bond, realizing the chemical anchoring of the pre-base integration reagent and the zinc-aluminum-magnesium coating. At the same time, the organic functional groups (such as amino and epoxy groups) at the other end of the silane molecule undergo a cross-linking reaction with the resin molecular chain to construct a three-dimensional chemical bridging network of "zinc-aluminum-magnesium coating-silane-resin", which completely solves the problem that the traditional coating and substrate are not firmly bonded by physical adsorption alone. Based on this, the corrosion inhibitor includes a compound composed of sodium phytate and chitosan, with a mass ratio of sodium phytate to chitosan of 3-5:1. The phosphate groups of sodium phytate can undergo a complexation reaction with exposed metal ions on the zinc-aluminum-magnesium coating surface, forming a dense chelate film inside the chemical bonding layer. Chitosan, through the amino and hydroxyl groups in its molecules, forms hydrogen bonds with the silane cross-linking network, further enhancing the interfacial bonding stability. An adhesion promoter reduces the surface tension of the zinc-aluminum-magnesium coating, promoting rapid wetting and uniform spreading of the pre-base bonding agent on the coating surface, ensuring that the chemical bonding reaction occurs fully across the entire interface. The film-forming aid is propylene glycol methyl ether acetate, which lowers the resin film-forming temperature, allowing the resin to complete molecular chain cross-linking under natural drying conditions, forming a continuous and dense organic film layer that completely encapsulates the chemical bonding interface. Ultimately, a composite transitional bonding layer of "chemical anchoring + physical coating + corrosion inhibition enhancement" is formed on the zinc-aluminum-magnesium coating surface.

[0037] This invention achieves a performance breakthrough through a synergistic anti-corrosion system of "zinc-aluminum-magnesium coated plate + pre-base integrated reagent + topcoat". One of its core innovations lies in the highly efficient interface bonding mechanism between the zinc-aluminum-magnesium coating and the pre-base integrated reagent: Unlike the traditional approach of multi-layer coatings that achieve protection solely through physical stacking, this invention utilizes the dual reactivity of silane to construct a stable chemical covalent bond between the zinc-aluminum-magnesium coating and the pre-base integrated reagent. Combined with the complexation strengthening and hydrogen bonding effects of the corrosion inhibitor, the interface bonding strength is increased by more than 60%, completely solving industry pain points such as interface peeling and blistering that are prone to occur in traditional coatings. At the same time, the resulting "chemical anchoring + physical coating" composite transition bonding layer not only possesses excellent corrosion media barrier capabilities but also provides a good adhesion substrate for the subsequent topcoat, enabling a tight intermolecular force to form between the topcoat and the transition layer. Furthermore, the Zn-Al / MgZn2 ternary eutectic structure of the zinc-aluminum-magnesium coated plate possesses excellent sacrificial anode protection (reducing corrosion current density by an order of magnitude compared to traditional weathering steel plates). Combined with the weather resistance and anti-aging properties of the high-performance polyurethane topcoat, the three form a complementary and synergistic anti-corrosion system of "sacrificial anode protection - chemical interface barrier - surface weathering protection." The overall corrosion resistance far exceeds that of the existing "zinc powder primer + intermediate coat + topcoat" system, with salt spray corrosion tolerance exceeding 3000 hours, extending the service life of dry cargo containers to 15-20 years. This invention, through the innovation of the aforementioned interface bonding mechanism, achieves a dual breakthrough of "simplifying the coating structure" and "improving anti-corrosion performance," demonstrating significant technological innovation.

[0038] (3) The container plates are cut, bent, welded and assembled to obtain a dry cargo container; (4) Apply topcoat to the surface of the dry cargo container with a coating amount of 0.1-1.0 L / m² and dry after coating.

[0039] The topcoat can be a water-based acrylic topcoat, and the spraying amount of the topcoat can be 0.1-1.0L / m², which can make the topcoat evenly and effectively sprayed and cured on the surface of the dry cargo container.

[0040] The drying temperature is 65-85℃ and the drying time is 1-2 hours, which can make the topcoat dry quickly, fully and evenly, and allow the topcoat to cure evenly on the surface of the dry cargo container. Example

[0041] (1) Degrease and dust removal treatment is carried out on the surface of the container plate to remove oil, dust and impurities on the surface of the container plate and ensure the cleanliness of the surface of the container plate; the surface of the coated plate is degreased for 3 minutes at 40°C using an alkaline degreaser, then rinsed with clean water and dried; then the surface dust and impurities are removed by high-pressure airflow combined with vacuum dust collection to complete the substrate pretreatment.

[0042] The container panels are coated with a zinc-aluminum-magnesium oxide (ZAMC) coating, which has a thickness of 80 g / m². 2 .

[0043] The weight percentages of each component in the zinc-aluminum-magnesium coating are: Al 5%, Mg 1%, Zn 93.5%.

[0044] (2) A pre-base bonding agent is coated on the surface of the container plate, with a coating amount of 0.02 L / m², so that a dense transition bonding layer is formed on the surface of the container plate.

[0045] The pre-base integration reagent comprises the following components in parts by weight: 5 parts silane, 15 parts resin, 3 parts corrosion inhibitor (sodium phytate: chitosan = 3:1), 2 parts adhesion promoter, and 2 parts propylene glycol methyl ether acetate.

[0046] (3) Cut, bend, weld and assemble the processed container plates to obtain the finished dry cargo container.

[0047] (4) Apply a topcoat to the surface of the dry cargo container at a coating amount of 0.19 L / m². 2 After spraying, the coating is dried at 70℃ for 1 hour.

[0048] Comparative Example 1 (1) Substrate pretreatment: Weathering steel plate is selected as the container plate. The weathering steel plate is mechanically sanded to remove surface oxide scale and oil stains. Compressed air is used to blow away dust, and the surface cleanliness reaches Sa2.5 level.

[0049] (2) Primer spraying: Epoxy zinc-rich primer is sprayed on the surface of weathering steel plate at a spraying amount of 0.06L / m², and dried at 40℃ for 5-8 minutes to form a primer layer with a dry film thickness of 30μm on the surface of weathering steel plate.

[0050] (3) Weld and assemble the coated weathering steel plates into dry cargo containers.

[0051] (4) Intermediate coat spraying: Spray epoxy intermediate coat at a rate of 0.13 L / m², and place in an oven at 50-65℃ for 5-10 minutes to form an intermediate coat with a dry film thickness of 50 μm.

[0052] (5) Topcoat spraying: After the intermediate coat is dry, spray the acrylic topcoat at a rate of 0.11 L / m² and place it in the oven at 55-75℃ for 3-8 minutes to form a topcoat layer with a dry film thickness of 40 μm.

[0053] Salt spray corrosion resistance tests were conducted on the dry cargo containers of Example 1 and Comparative Example 1. The dry cargo container of Example 1... The salt spray corrosion resistance time can reach more than 3000 hours, which can extend the service life of dry cargo containers to 15-20 years. The salt spray corrosion resistance time requirement for the dry cargo container in Comparative Example 1 is more than 1200 hours, with a service life of more than 10 years.

[0054] As can be seen from the above test results, the dry cargo container of Embodiment 1 of the present invention has superior corrosion resistance and a longer service life compared with the dry cargo container of Comparative Example 1.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A corrosion protection process for dry cargo containers, characterized in that, include: (1) Degrease and dust removal treatment is carried out on the surface of the container plates to remove oil, dust and impurities from the surface of the container plates and ensure the cleanliness of the container plate surface. (2) A pre-base bonding agent is coated on the surface of the container plate, with a coating amount of 0.02-0.05 L / m², so that a dense transition bonding layer is formed on the surface of the container plate; (3) The container plates are cut, bent, welded and assembled to obtain a dry cargo container; (4) Apply a topcoat to the surface of the dry cargo container, with a coating amount of 0.1-1.0 L / m², and then dry it after the coating is completed.

2. The anti-corrosion treatment process for dry cargo containers as described in claim 1, characterized in that, In step (1), the surface of the container plate is coated with a zinc-aluminum-magnesium coating, the thickness of which is 80-120 g / m². 2 .

3. The anti-corrosion treatment process for dry cargo containers as described in claim 1, characterized in that, In step (1), the weight percentages of each component in the zinc-aluminum-magnesium coating are: Al 5-12%, Mg 1-6%, Zn 76-95%.

4. The anti-corrosion treatment process for dry cargo containers as described in claim 1, characterized in that, The degreasing and dust removal process in step (1) includes: using an alkaline degreasing agent, treating at 40-50℃ for 3-5 minutes, then rinsing with clean water and drying; the dust removal process uses a combination of high-pressure airflow blowing and vacuum dust collection.

5. The anti-corrosion treatment process for dry cargo containers as described in claim 1, characterized in that, In step (2), the pre-base integration reagent comprises the following components in parts by weight: 5-10 parts of silane, 15-25 parts of resin, 3-5 parts of corrosion inhibitor, 2-4 parts of adhesion promoter, and 2-4 parts of film-forming aid.

6. The anti-corrosion treatment process for dry cargo containers as described in claim 5, characterized in that, The corrosion inhibitor comprises sodium phytate and chitosan, with a mass ratio of sodium phytate to chitosan of 3-5:

1.

7. The anti-corrosion treatment process for dry cargo containers as described in claim 5, characterized in that, The film-forming aid includes propylene glycol methyl ether acetate.

8. The anti-corrosion treatment process for dry cargo containers as described in claim 5, characterized in that, The adhesion promoter comprises epoxy phosphate compounds and epoxy silane coupling agents, with a mass ratio of epoxy phosphate compounds to epoxy silane coupling agents of 2:1 to 3:

1.

9. The anti-corrosion treatment process for dry cargo containers as described in claim 1, characterized in that, In step (4), the drying temperature is 65-85℃ and the drying time is 1-2h.