Refrigerated container and process for its production

Abstract

This invention discloses a refrigerated container and its manufacturing process. The refrigerated container includes door panels, side panels, and a top panel. Each door panel, side panel, and top panel includes a substrate. The outer surface of the substrate is provided with an alloy plating layer, an outer coating layer, and a topcoat layer. The inner surface of the substrate is provided with an alloy plating layer and an inner coating layer. The alloy plating layer on the outer surface of the door panel has a coating weight of 40-60 g / m², and the alloy plating layer on the inner surface of the door panel has a coating weight of 40-60 g / m². The alloy plating layer on the outer surface of the side panel has a coating weight of 40-50 g / m², and the alloy plating layer on the inner surface of the side panel has a coating weight of 40-50 g / m². The alloy plating layer on the outer surface of the top panel has a coating weight of 50-60 g / m², and the alloy plating layer on the inner surface of the top panel has a coating weight of 50-60 g / m². The corrosion resistance of refrigerated containers has been significantly upgraded. All panels are made of zinc-aluminum-magnesium coated plates from China Aluminum, combined with coatings and differentiated local anti-corrosion reinforcement structures in various parts. The entire container can withstand a neutral salt spray test of ≥2000h.

Description

Technical Field

[0001] This invention relates to the field of refrigerated container technology, and more specifically to a refrigerated container and its manufacturing process. Background Technology

[0002] Currently, the main outer panels of refrigerated containers, including doors, outer side panels, and outer roof panels, are made of MGSS stainless steel. The coating process for each part is sandblasting of the outer surface + 55μm epoxy water-based primer + 35μm water-based topcoat, while the inner surface is separately sprayed with 15μm expanding foam. Each part of the outer panel needs to be painted independently, which has many insurmountable technical defects. The production process is lengthy and complicated. All parts of the outer panel of the box need to go through nine core processes, including material cutting, bending, welding, grinding, sanding, primer spraying, primer drying, topcoat spraying, topcoat drying, and foaming adhesive spraying. It has a high degree of reliance on manual labor, poor adaptability to automated production, long production cycle, and low production efficiency.

[0003] The surface roughness of MGSS stainless steel is difficult to control after sandblasting, which can easily lead to surface oxidation and iron filings. This results in insufficient adhesion of epoxy water-based primer, and weak parts such as welds, corners, and joints of the outer panels are prone to missed coating and pinholes. It is also extremely easy to rust in the salt spray environment of the ocean, with a salt spray resistance of only ≥1000h, which limits the service life of refrigerated containers in ocean-going operations.

[0004] The on-site application of epoxy water-based primer and foam adhesive has extremely high requirements for temperature, humidity and cleanliness. It is easy to cause paint film defects and uneven bonding of foam adhesive. In particular, the large-area foam bonding area of ​​the outer panel is prone to delamination and hollowing, resulting in a low yield of finished products.

[0005] The procurement cost of MGSS stainless steel is high, and each part of the outer panel of the entire box needs to be coated with primer and foam separately. The costs of materials, labor, and drying energy consumption are added up, resulting in a high overall manufacturing cost. At the same time, the cut edges of MGSS stainless steel have no self-healing ability, making later maintenance difficult and costly.

[0006] Currently, existing technologies only improve the zinc-aluminum-magnesium plate + pre-bottom integrated coating technology for refrigerated container doors, but have not achieved the application of this technology to the entire outer panel of refrigerated containers. This cannot solve the aforementioned industry pain points of the entire outer panel. The industry urgently needs a refrigerated container structure that can simplify the process of the entire outer panel, upgrade corrosion protection, and reduce costs. Summary of the Invention

[0007] The purpose of this invention is to provide a refrigerated container that at least partially addresses the technical deficiencies mentioned in the background art.

[0008] Therefore, the present invention provides a refrigerated container, including a door panel, side panels, and a top panel. Each of the door panel, side panels, and top panel includes a substrate. The outer surface of the substrate is sequentially provided with an alloy plating layer, an outer coating layer, and a topcoat layer; the inner surface of the substrate is sequentially provided with an alloy plating layer and an inner coating layer. The alloy plating layer on the outer surface of the door panel has a coating weight of 40-60 g / m², and the alloy plating layer on the inner surface of the door panel has a coating weight of 40-60 g / m². The alloy plating layer on the outer surface of the side panels has a coating weight of 40-50 g / m², and the alloy plating layer on the inner surface of the side panels has a coating weight of 40-50 g / m². The alloy plating layer on the outer surface of the top panel has a coating weight of 50-60 g / m², and the alloy plating layer on the inner surface of the top panel has a coating weight of 50-60 g / m².

[0009] In some embodiments of the present invention, the coating of the outer coating comprises a modified epoxy ester resin, an adhesion promoter and a salt spray resistant agent, wherein the mass ratio of the modified epoxy ester resin, the adhesion promoter and the salt spray resistant agent is (85-95): (2-8): (3-7).

[0010] In some embodiments of the present invention, the adhesion promoter comprises an organophosphorus coupling agent and / or a silane coupling agent.

[0011] In some embodiments of the present invention, the salt spray resistant additive includes a flake-shaped shielding agent, a hydrotalcite ion scavenger, and a chromium-free corrosion inhibitor, wherein the mass ratio of the flake-shaped shielding agent, the hydrotalcite ion scavenger, and the chromium-free corrosion inhibitor is (50-60): (25-35): (10-20).

[0012] In some embodiments of the present invention, the coating composition of the topcoat layer includes waterborne polyurethane, and the thickness of the topcoat layer is 30-40 μm.

[0013] In some embodiments of the present invention, the coating of the inner coating comprises polyurethane modified acrylic resin and foaming interface compatibilizer, wherein the mass ratio of polyurethane modified acrylic resin to foaming interface compatibilizer is (90-99): (1-10).

[0014] In some embodiments of the present invention, the foaming interface compatibilizer includes hydroxyl-terminated polyurethane prepolymer, polyurethane-grafted acrylate copolymer, modified polyether polyol, and polyether-modified organosilicon.

[0015] In some embodiments of the present invention, the mass ratio of hydroxyl-terminated polyurethane prepolymer, polyurethane grafted acrylate copolymer, modified polyether polyol and polyether modified organosilicon is (50-60): (25-35): (8-15): (2-5).

[0016] The present invention also provides a manufacturing process for the aforementioned refrigerated container, comprising: (1) Select zinc-aluminum-magnesium alloy coated plates as the base material for door panels, side panels and top panels; coat the outer side of the zinc-aluminum-magnesium alloy coated plates with an outer coating and coat the inner side of the zinc-aluminum-magnesium alloy coated plates with an inner coating. (2) The zinc-aluminum-magnesium alloy coated sheet is bent into door panels, side panels and top panels; (3) Weld and assemble the door panels, side panels and top panel into a refrigerated container; (4) Locally repair the damaged areas of the coating on the welds and bends of the door panel, side panel and top panel. After the coating is dried at room temperature, apply weather-resistant polyurethane sealant to the edge of the door panel to achieve full sealing and corrosion protection. (5) Apply a topcoat layer to the outer surface of the door panel, side panel and top panel, dry and cure to obtain a refrigerated container.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are: The corrosion resistance of the refrigerated container of this invention is significantly upgraded: the entire plate adopts a zinc-aluminum-magnesium coated plate with self-healing cut characteristics, combined with a pre-base integrated coating and differentiated local anti-corrosion reinforcement structure in each part. The whole container has no red rust after ≥2000h neutral salt spray test. The corrosion resistance of weak parts such as welds, corners and plate seams is improved compared with traditional processes, thus extending the service life of refrigerated containers in ocean-going operations.

[0018] The entire production process is extremely streamlined: four redundant processes have been eliminated, namely, surface sanding of all parts of the outer panel, epoxy water-based primer spraying, primer drying, and inner surface foaming adhesive spraying. The traditional nine processes have been simplified into five unified processes, reducing the production cycle by more than 60% compared to the traditional process. There is no dust pollution during the production process, which is suitable for fully automated mass production of the entire container and greatly improves production efficiency.

[0019] Fully compatible with existing systems, zero modification cost: All outer panels use industry-standard 35μm water-based topcoat, without the need to change existing coating lines, topcoat formulas and curing parameters, achieving a seamless switch from traditional processes to new processes, without requiring additional modification costs for enterprises.

[0020] Comprehensive enhancement of interface bonding: The double-sided differentiated pre-base coating has been finely formulated for the characteristics of each outer panel. The outer side significantly improves the bonding strength between topcoat layers, eliminating problems such as paint film peeling, pinholes, and blistering. The inner side strengthens the bonding strength with the thermal insulation foam layer, completely solving problems such as foam delamination, hollowing, and uneven bonding. In particular, it improves the stability of large-area foam bonding on the outer panel.

[0021] The overall cost of the container is significantly reduced: the procurement cost of pre-coated zinc-aluminum-magnesium steel sheets from Chalco is 50% lower than that of MGSS stainless steel. At the same time, it eliminates the material costs of epoxy primer, foaming adhesive, and sandblasting for the entire container, as well as related costs such as labor, drying energy consumption, and environmental protection. The overall manufacturing cost of a single container is reduced by more than 50% compared to traditional processes, and the economies of scale in mass production are particularly prominent.

[0022] Significantly improved finished product yield: The pre-primer integrated coating is formed by standardized roller coating in steel mills, with uniform film thickness, no missed coating, and no pinholes. It avoids the process defects of on-site water-based primer and foaming adhesive application from the source. The overall qualified rate of refrigerated containers is greatly improved compared with traditional processes, reducing production rework costs.

[0023] Green and environmentally friendly with easy maintenance: The production process eliminates the sandblasting step, resulting in no dust pollution. The coating is a water-based environmentally friendly formula that does not contain heavy metals, meeting the requirements of green production. The zinc-aluminum-magnesium coating has self-healing properties at the cuts, so minor scratches on the outer panel of the refrigerated container do not require additional anti-corrosion treatment, making maintenance convenient and cost-effective. Detailed Implementation

[0024] 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.

[0025] The present invention provides a refrigerated container, which includes doors, side panels and a top panel.

[0026] The door panel includes a base plate, the thickness of which is 1.6mm.

[0027] For the door panel, the outer surface of its substrate is sequentially coated with an alloy plating layer, an outer coating layer, and a topcoat layer, while the inner surface of its substrate is sequentially coated with an alloy plating layer and an inner coating layer. The alloy plating amount on the outer surface of the door panel is 40-60 g / m², and the alloy plating amount on the inner surface of the door panel is also 40-60 g / m². By setting these plating amounts, the door panel can be adapted to the force characteristics of opening and closing.

[0028] The side panel includes a substrate, the thickness of which is 0.8-1.0 mm.

[0029] For the side panel, the outer surface of its substrate is sequentially coated with an alloy plating layer, an outer coating layer, and a topcoat layer, while the inner surface of its substrate is sequentially coated with an alloy plating layer and an inner coating layer. The alloy plating amount on the outer surface of the side panel is 40-50 g / m², and the alloy plating amount on the inner surface of the side panel is also 40-50 g / m². By setting these plating amounts, the side panel can meet both the corrosion resistance requirements of a large flat surface and a lightweight design.

[0030] The top plate includes a substrate, the thickness of which is 0.8-1.0 mm.

[0031] For the roof slab, the outer surface of the substrate is sequentially coated with an alloy plating layer, an outer coating layer, and a topcoat layer, while the inner surface of the substrate is sequentially coated with an alloy plating layer and an inner coating layer. The alloy plating amount on the outer surface of the roof slab is 50-60 g / m², and the alloy plating amount on the inner surface of the roof slab is also 50-60 g / m². By setting these plating amounts, the corrosion resistance of the roof slab against impact and rainwater and salt spray buildup can be improved.

[0032] The alloy coating is a medium-aluminum zinc-aluminum-magnesium alloy coating. Its coating composition, by weight, includes the following components: Al 9-11wt%, Mg 2.8-3.1wt%, Si 0.1-0.2wt%, with the balance being Zn.

[0033] The alloy coating possesses self-healing properties at the cut, and its resistance to marine salt spray is superior to MGSS stainless iron. The self-healing principle of zinc-aluminum-magnesium alloy is as follows: after the coating is damaged, Mg and Al ions dissolve and react with moisture and oxygen in the environment to form a dense alkaline protective film at the damaged site, preventing the spread of rust. This process requires the coating to provide sufficient Mg, Al, and Zn ions as "repair materials".

[0034] The coating for the outer layer consists of modified epoxy ester resin, adhesion promoter and salt spray resistant additive, with a mass ratio of (85-95): (2-8): (3-7).

[0035] Adhesion promoters include organophosphorus coupling agents and / or silane coupling agents.

[0036] Salt spray resistant additives include flake shielding agent, hydrotalcite ion scavenger and chromium-free corrosion inhibitor, with a mass ratio of (50-60): (25-35): (10-20).

[0037] The topcoat layer consists of water-based polyurethane, and its thickness is 30-40 μm.

[0038] The outer coating is based on modified epoxy ester resin, combined with an organophosphorus / silane composite adhesion promoter. The active functional groups on its molecular chain undergo an irreversible chemical cross-linking reaction with the functional groups of the waterborne polyurethane topcoat, forming covalent bonds / coordination bonds. This transforms the two coatings from "physical adhesion" to "molecular-level fusion," which is the core reason why the interlayer bonding strength far exceeds that of traditional processes.

[0039] The core function of the outer coating is to strengthen the interlayer adhesion with the water-based polyurethane topcoat layer, ensuring that the topcoat does not peel off or bubble. The coating of the inner coating consists of polyurethane modified acrylic resin and foaming interface compatibilizer, with a mass ratio of polyurethane modified acrylic resin to foaming interface compatibilizer of (90-99): (1-10).

[0040] Foaming interface compatibilizers include hydroxyl-terminated polyurethane prepolymers, polyurethane-grafted acrylate copolymers, modified polyether polyols, and polyether-modified organosilicones.

[0041] The mass ratio of hydroxyl-terminated polyurethane prepolymer, polyurethane-grafted acrylate copolymer, modified polyether polyol and polyether-modified organosilicon is (50-60): (25-35): (8-15): (2-5).

[0042] The core function of the inner coating is to enhance the bonding strength with the rigid polyurethane foam inside the refrigerator, preventing delamination and blistering. The inner coating relies on the structural homology of the resin matrix for basic bonding, the directional interface regulation and strengthening by the compatibilizer, the dense physical micro-interlocking, and the long-term guarantee of environmental weather resistance. These four functions work synergistically to eliminate the core causes of delamination and blistering, ultimately achieving high-strength and long-lasting bonding with the rigid polyurethane foam.

[0043] This invention also provides a manufacturing process for refrigerated containers, including: (1) Zinc-aluminum-magnesium alloy coated plates are selected as the substrate for door panels, side panels and top panels; an outer coating is applied to the outer side of the zinc-aluminum-magnesium alloy coated plate, and an inner coating is applied to the inner side of the zinc-aluminum-magnesium alloy coated plate; a precision double-sided three-roller coating process is used for forming, the curing temperature is 190℃, the curing time is 40s, the coating adhesion is grade 0 by cross-cut test, the thickness of the coating on each side is 8μm, the coating is a water-based environmentally friendly resin-based formula, and it does not contain heavy metals; the details are as follows: Door panel: Aluminum-based zinc-aluminum-magnesium alloy coated plate, with a base material thickness of 1.6mm and a coating composition of Al 10wt%, Mg 3.0wt%, Si 0.15wt%, with the balance being Zn; the coating amount of the outer side coating on the door panel is 50g / m², and the coating amount of the inner side coating on the door panel is 50g / m². Side panels: Aluminum-based zinc-aluminum-magnesium alloy coated plates, with a base material thickness of 1.0 mm and a coating composition of Al 10 wt%, Mg 3.0 wt%, Si 0.15 wt%, with the balance being Zn; the thickness is within the upper limit of the 0.8-1.0 mm range, balancing the structural rigidity and lightweight requirements of large-area side panels; the coating amount on the outer side of the side panel is 50 g / m², and the coating amount on the inner side of the side panel is 50 g / m². Top plate: Aluminum-based zinc-aluminum-magnesium alloy coated plate, with a base material thickness of 1.0 mm and a coating composition of Al 10wt%, Mg 3.0wt%, Si 0.15wt%, with the balance being Zn; the coating amount of the outer coating on the top plate is 50 g / m², and the coating amount of the inner coating on the top plate is 50 g / m². The coating components of the outer coating of the door panel and the side panel are the same, specifically including modified epoxy ester resin, adhesion promoter and salt spray resistant additive. The mass ratio of modified epoxy ester resin, adhesion promoter and salt spray resistant additive is (85-95): (2-8): (3-7).

[0044] The coating on the outer side of the top plate specifically includes modified epoxy ester resin, adhesion promoter, salt spray resistant agent and ultraviolet resistant agent. The mass ratio of modified epoxy ester resin, adhesion promoter, salt spray resistant agent and ultraviolet resistant agent is (85-95): (2-8): (3-7): (3-7).

[0045] The coating components on the inner side of the door panel and the top panel are the same, specifically including 95% polyurethane modified acrylic resin + 5% foaming interface compatibilizer. The coating on the inner side panel consists of 92% polyurethane-modified acrylic resin and 8% foaming interface compatibilizer.

[0046] (2) The zinc-aluminum-magnesium alloy coated sheet is bent into door panels, side panels and top panels; (3) Weld and assemble the door panels, side panels and top panel into a refrigerated container; (4) Locally repair the coating damage at the welds and bends of the door panels, side panels, and top panels. After surface drying at room temperature, apply weather-resistant polyurethane sealant to the edges of the door panels to achieve full sealing and corrosion protection; the details are as follows: Door panel: For damaged areas of the coating at weld seams and corners of the door frame, apply epoxy repair paint of the same system, with a dry film thickness of 80μm. After surface drying at room temperature, apply weather-resistant polyurethane sealant. Side panels: Apply epoxy repair paint of the same system to the joints of the panels and the welded areas connected to the corner posts. The dry film thickness of the repair paint should be 80μm. After it is surface dry at room temperature, apply weather-resistant polyurethane sealant. Top plate: Apply epoxy repair paint of the same system to the top edges and irregular parts connected to the cold storage compartment. The dry film thickness of the repair paint should be 100μm. After it is surface dry at room temperature, apply high weather-resistant polyurethane sealant.

[0047] (5) Apply a 35μm topcoat layer to the outer surface of the door panel, side panel and top panel, and dry and cure with hot air at low temperature. The curing temperature is 80℃ and the drying time is 30min to obtain a refrigerated container.

[0048] The refrigerated container's outer panels of this invention have undergone professional testing, and all performance characteristics meet the stringent requirements of ocean shipping: the coating adhesion is grade 0 across the grid; after 50 cycles of high and low temperatures from -40℃ to 70℃, there is no coating peeling, no foaming or delamination, and no paint film cracking; after 2000 hours of neutral salt spray testing, there is no red rust, no blistering, and no paint film chalking; there is no rust on weak areas such as welds and corners; the bonding strength between the insulation foam layer and the inner surface pre-primer coating is ≥0.8MPa; there are no hollow areas or delamination in the large foamed areas of the outer panels; the production cycle of the outer panels is shortened by 65% ​​compared to the traditional MGSS stainless steel process, and the overall manufacturing cost per container is reduced by 55% compared to the traditional process; the 1.0mm thick side panels and top panels are matched with corresponding coating amounts, achieving an optimal balance between performance and cost control; the first-pass yield of finished products is increased by more than 20% compared to the traditional process, and there are no rework problems such as paint film defects or uneven foaming and bonding.

[0049] The corrosion resistance of the refrigerated container of this invention is significantly upgraded: all outer panels are made of aluminum-based zinc-aluminum-magnesium coated plates with self-healing cut characteristics, combined with a pre-coating and bottom-coating, and differentiated local anti-corrosion reinforcement structures in various parts. The whole container can withstand ≥2000h of neutral salt spray test without red rust. The corrosion resistance of weak parts such as welds, corners, and plate seams is improved compared with traditional processes, thus extending the service life of refrigerated containers in ocean-going operations.

[0050] The entire production process is extremely streamlined: four redundant processes have been eliminated, namely, surface sanding of all parts of the outer panel, epoxy water-based primer spraying, primer drying, and inner surface foaming adhesive spraying. The traditional nine processes have been simplified into five unified processes, reducing the production cycle by more than 60% compared to the traditional process. There is no dust pollution during the production process, which is suitable for fully automated mass production of the entire container and greatly improves production efficiency.

[0051] Fully compatible with existing systems, zero modification cost: All outer panels use industry-standard 35μm water-based topcoat, without the need to change existing coating lines, topcoat formulas and curing parameters, achieving a seamless switch from traditional processes to new processes, without requiring additional modification costs for enterprises.

[0052] Comprehensive enhancement of interface bonding: The double-sided differentiated pre-base coating has been finely formulated for the characteristics of each outer panel. The outer side significantly improves the bonding strength between topcoat layers, eliminating problems such as paint film peeling, pinholes, and blistering. The inner side strengthens the bonding strength with the thermal insulation foam layer, completely solving problems such as foam delamination, hollowing, and uneven bonding. In particular, it improves the stability of large-area foam bonding on the outer panel.

[0053] The overall cost of the container is significantly reduced: the procurement cost of pre-coated zinc-aluminum-magnesium steel sheets from Chalco is 50% lower than that of MGSS stainless steel. At the same time, it eliminates the material costs of epoxy primer, foaming adhesive, and sandblasting for the entire container, as well as related costs such as labor, drying energy consumption, and environmental protection. The overall manufacturing cost of a single container is reduced by more than 50% compared to traditional processes, and the economies of scale in mass production are particularly prominent.

[0054] Significantly improved finished product yield: The pre-primer integrated coating is formed by standardized roller coating in steel mills, with uniform film thickness, no missed coating, and no pinholes. It avoids the process defects of on-site water-based primer and foaming adhesive application from the source. The overall qualified rate of refrigerated containers is greatly improved compared with traditional processes, reducing production rework costs.

[0055] Green and environmentally friendly with easy maintenance: The production process eliminates the sandblasting step, resulting in no dust pollution. The coating is a water-based environmentally friendly formula that does not contain heavy metals, meeting the requirements of green production. The zinc-aluminum-magnesium coating has self-healing properties at the cuts, so minor scratches on the outer panel of the refrigerated container do not require additional anti-corrosion treatment, making maintenance convenient and cost-effective.

[0056] 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 refrigerated container, comprising doors, side panels, and a top panel, characterized in that, The door panel, the side panel, and the top panel all include a base plate. The outer surface of the substrate is sequentially provided with an alloy plating layer, an outer coating layer, and a topcoat layer; The inner surface of the substrate is provided with an alloy plating layer and an inner coating layer in sequence; The coating amount of the alloy plating on the outer side of the door panel is 40-60 g / m², and the coating amount of the alloy plating on the inner side of the door panel is 40-60 g / m². The coating amount of the alloy coating on the outer side of the side plate is 40-50 g / m², and the coating amount of the alloy coating on the inner side of the side plate is 40-50 g / m². The coating amount of the alloy coating on the outer side of the top plate is 50-60 g / m², and the coating amount of the alloy coating on the inner side of the top plate is 50-60 g / m².

2. The refrigerated container as described in claim 1, characterized in that, The coating for the outer layer comprises a modified epoxy ester resin, an adhesion promoter, and a salt spray resistant additive. The mass ratio of modified epoxy ester resin, adhesion promoter and salt spray resistant additive is (85-95): (2-8): (3-7).

3. The refrigerated container as described in claim 2, characterized in that, The adhesion promoter includes organophosphorus coupling agents and / or silane coupling agents.

4. The refrigerated container as described in claim 2, characterized in that, The salt spray resistant additives include flake-shaped shielding agents, hydrotalcite ion scavengers, and chromium-free corrosion inhibitors. The mass ratio of the sheet-like shielding agent, the hydrotalcite ion scavenger, and the chromium-free corrosion inhibitor is (50-60): (25-35): (10-20).

5. The refrigerated container as described in claim 1, characterized in that, The coating composition of the topcoat layer includes water-based polyurethane, and the thickness of the topcoat layer is 30-40 μm.

6. The refrigerated container as described in claim 1, characterized in that, The coating for the inner side includes a polyurethane-modified acrylic resin and a foaming interface compatibilizer. The mass ratio of polyurethane modified acrylic resin to foaming interface compatibilizer is (90-99): (1-10).

7. The refrigerated container as described in claim 6, characterized in that, The foaming interface compatibilizer includes hydroxyl-terminated polyurethane prepolymer, polyurethane-grafted acrylate copolymer, modified polyether polyol, and polyether-modified organosilicon.

8. The refrigerated container as described in claim 7, characterized in that, The mass ratio of hydroxyl-terminated polyurethane prepolymer, polyurethane-grafted acrylate copolymer, modified polyether polyol and polyether-modified organosilicon is (50-60): (25-35): (8-15): (2-5).

9. A manufacturing process for a refrigerated container as described in any one of claims 1-8, characterized in that, include: (1) Zinc-aluminum-magnesium alloy coated plates are selected as the base plates for door panels, side panels and top panels; An outer coating is applied to the outer side of the zinc-aluminum-magnesium alloy coated plate, and an inner coating is applied to the inner side of the zinc-aluminum-magnesium alloy coated plate. (2) The zinc-aluminum-magnesium alloy coated sheet is bent into door panels, side panels and top panels; (3) Weld and assemble the door panels, side panels and top panel into a refrigerated container; (4) Locally repair the damaged areas of the coating on the welds and bends of the door panel, side panel and top panel. After the coating is dried at room temperature, apply weather-resistant polyurethane sealant to the edge of the door panel to achieve full sealing and corrosion protection. (5) Apply a topcoat layer to the outer surface of the door panel, side panel and top panel, dry and cure to obtain a refrigerated container.