All-water-based coating metal composite coiled material and manufacturing process thereof

Abstract

The invention provides a manufacturing process of a full water-based coating metal composite coiled material, which comprises the following steps: sequentially coating one side of a PET (Polyethylene Terephthalate) protective layer with water-based ink, water-based polyester primer and water-based hot melt adhesive to form a composite auxiliary material layer; uncoiling the metal substrate; the composite auxiliary material layer is attached to one side of the metal substrate in a hot-pressing mode; wherein the PET protective layer is far away from the metal substrate; and cooling the metal substrate with the composite auxiliary material layer, and coiling to obtain the full water-based coating metal composite coiled material. The water-based polyester primer, the water-based hot melt adhesive and the water-based ink are adopted to construct a full water-based coating system, so that the problem of volatilization pollution of an organic solvent in an oil-based coating is solved, the smoke emission and fire hazards in a traditional process are reduced, the green and environment-friendly production process is realized, meanwhile, the production process is simplified, the equipment capital investment is reduced, and the production cost is reduced; the production benefit is improved.

Description

Technical Field

[0001] This application relates to the technical field of metal coil preparation, and particularly to a fully water-based coated metal composite coil and its manufacturing process. Background Art

[0002] Color-coated plates and film-coated plates are widely used metal composite plates in industrial production. Due to their excellent decorative properties, corrosion resistance, and processing performance, they are widely used in fields such as construction, household appliances, and automobiles. Among them, color-coated plates are made by coating or laminating various organic coatings or plastic films on the surface of metal coils, such as cold-rolled plates, hot-dip galvanized plates, etc.; while film-coated plates are made by a processing technology that hot-presses a plastic film and a metal plate at high temperature to stick the film on the metal plate.

[0003] However, there are still many deficiencies in the production processes and application performances of ordinary color-coated plates and film-coated plates in the prior art. On the one hand, ordinary color-coated plates use non-environmental protection raw materials such as oil-based paints, and problems such as the volatilization of oil-based paint odors and flue gas emissions will occur during the production process, which not only poses a threat to the health of employees but also easily causes fire hazards. At the same time, the production line of ordinary color-coated plates is usually hundreds of meters long, with a large investment in equipment funds, and high energy consumption for starting and stopping, resulting in high comprehensive manufacturing costs. In addition, the colors of ordinary color-coated plates are single, and it is difficult to present complex texture patterns such as high-precision wood grains and stone grains, which cannot meet the market's demand for personalized decoration. On the other hand, metal composite plates based on ordinary galvanized plates and the like need to go through multiple pretreatment steps, and the preparation process is complex. Moreover, film-coated plates also need to use oil-based adhesives and be equipped with baking furnaces, further increasing the production difficulty and cost. Summary of the Invention

[0004] In view of the above problems, this application is proposed to provide a fully water-based coated metal composite coil and its manufacturing process that can overcome or at least partially solve the above problems, including: A manufacturing process of a fully water-based coated metal composite coil, comprising the following steps: Sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary layer; Unroll the metal substrate; Thermally press and bond the composite auxiliary layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate; Cool the metal substrate with the composite auxiliary layer, and obtain the fully water-based coated metal composite coil after coiling.

[0005] Preferably, the step of sequentially coating water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary layer includes: Coat the water-based ink on one side of the PET protective layer to form a pattern layer; Coat the water-based polyester primer on the side of the pattern layer away from the PET protective layer to form a primer layer; Coat the water-based hot melt adhesive on the side of the primer layer away from the PET protective layer to form a hot melt adhesive layer, obtaining the composite auxiliary layer including the pattern layer, the primer layer, the hot melt adhesive layer and the PET protective layer.

[0006] Preferably, the step of thermally pressing and laminating the composite auxiliary layer onto the surface of the pre-heated metal substrate includes: Face the hot melt adhesive layer in the composite auxiliary layer towards the metal substrate; Continuously thermally press and laminate the composite auxiliary layer and the metal substrate at 150°C to 180°C through a laminating rubber roller, so that the composite auxiliary layer and the metal substrate form an integrated composite structure.

[0007] Preferably, the step of cooling the metal substrate with the composite auxiliary layer and obtaining the fully water-based coated metal composite coil after coiling includes: Cool down the metal substrate with the composite auxiliary layer by air cooling and water cooling, and obtain the fully water-based coated metal composite coil after coiling.

[0008] Preferably, the PET protective layer is a PET release film, and the step of cooling the metal substrate with the composite auxiliary layer and obtaining the fully water-based coated metal composite coil after coiling includes: Cool down the metal substrate with the composite auxiliary layer by air cooling and water cooling, and peel off the PET release film to obtain a preformed substrate; Coat water-based polyester topcoat and back paint on the upper and lower sides of the preformed substrate respectively, and perform high-temperature baking and curing, and the curing plate temperature is 224°C to 241°C; After baking, cool down by air cooling and water cooling, and obtain the fully water-based coated metal composite coil after coiling.

[0009] Preferably, before uncoiling the metal substrate, it further includes: Coat water-based anticorrosive material on the upper side of the metal substrate to form a passivation layer; Coat water-based anticorrosive foamable material on the lower side of the metal substrate to form a back coating.

[0010] A metal composite coil manufactured according to the above manufacturing process, comprising a metal substrate, a hot melt adhesive layer, a primer layer, a pattern layer, and a protective layer; the hot melt adhesive layer is provided on the upper side of the metal substrate, the primer layer is provided on the upper side of the hot melt adhesive layer, the pattern layer is provided on the upper side of the primer layer, and the protective layer is provided on the upper side of the pattern layer.

[0011] Preferably, it further comprises a passivation layer and a back coating; the passivation layer is provided on the side of the metal substrate close to the hot melt adhesive layer, and the back coating is provided on the side of the metal substrate away from the hot melt adhesive layer.

[0012] Preferably, the protective layer is a topcoat layer; a back coating is provided on the lower side of the metal substrate.

[0013] Preferably, the thickness of the metal substrate is 0.3 mm to 1.5 mm; the thickness of the hot melt adhesive layer is 1 µm to 5 µm; the thickness of the primer layer is 3 µm to 12 µm; the thickness of the pattern layer is 1 µm to 5 µm.

[0014] This application has the following advantages: In the embodiment of this application, in view of the problems of "serious production pollution, complex and lengthy production process, high equipment investment cost, and single product color effect" in the prior art, this application provides a solution for the manufacturing process of metal coils using a fully water-based coating, specifically: sequentially coating water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary layer; unrolling the metal substrate; thermally laminating the composite auxiliary layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate; cooling the metal substrate with the composite auxiliary layer, and obtaining the fully water-based coating metal composite coil after coiling. By constructing a fully water-based coating system with water-based polyester primer, water-based hot melt adhesive, and water-based ink, the volatilization pollution of organic solvents in the oil-based paint is eliminated, the problems of flue gas emission and fire hazards in the traditional process are solved, the green environmental protection of the production process is realized, the production efficiency is improved, and complex texture printing such as high-precision wood grain and stone grain can be realized, breaking through the limitation of the single color of ordinary color-coated plates. By thermally pressing and laminating the water-based hot melt adhesive and the water-based ink composite auxiliary layer with the metal substrate, the finished product has the functional attributes of color-coated plates and laminated plates, and at the same time, the equipment capital investment is reduced from the production process, the personnel and equipment operation are reduced, the production cost is reduced, and the production efficiency is improved. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of this application, the drawings required for the description of this application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 is a schematic flow chart of a manufacturing process of a fully water-based coated metal composite coil provided by an embodiment of the present application; Figure 2 is a schematic structural diagram of a fully water-based coated metal composite coil with a PET protective layer on the front side provided by an embodiment of the present application; Figure 3 is a schematic structural diagram of a fully water-based coated metal composite coil with a topcoat protective layer on the front side provided by an embodiment of the present application.

[0017] The reference signs in the accompanying drawings of the specification are as follows: 1. PET protective layer; 2. Pattern layer; 3. Primer layer; 4. Hot melt adhesive layer; 5. Passivation layer; 6. Metal substrate; 7. Back coating; 8. Topcoat protective layer. Detailed implementation manners

[0018] To make the objectives, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0019] The inventors found through analysis of the prior art that: traditional color-coated plates rely on oil-based paints, resulting in VOC pollution and fire hazards during the production process, and their coating processes are difficult to achieve high-precision complex textures, restricting the diversity of decorative effects; at the same time, laminated plates require oil-based adhesives and are equipped with heating and baking furnaces, and also include multiple processes such as superimposed degreasing pretreatment and multi-pass coating and baking, resulting in a long production line, high equipment investment, and the inability to effectively integrate the functional characteristics of color-coated plates and laminated plates. Therefore, inventing a fully water-based coated metal composite coil to solve environmental protection hazards and at the same time make the product meet the functional attributes of color-coated plates and laminated plates to balance environmental protection, functionality, and production efficiency has become a technical problem to be solved urgently.

[0020] Refer to Figure 1 , which shows a schematic flow chart of a manufacturing process of a fully water-based coated metal composite coil of the present application. The process includes: S110. Sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer; S120. Unroll the metal substrate; S130. Thermally bond the composite auxiliary material layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate; S140. Cool the metal substrate with the composite auxiliary material layer, and obtain the all-waterborne coated metal composite coil after coiling.

[0021] In the embodiment of the present application, aiming at the problems of "serious production pollution, complex and lengthy production process, high equipment investment cost, and single product color effect" in the prior art, the present application provides a solution for the manufacturing process of metal coils with all-waterborne coatings, specifically: sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer; unroll the metal substrate; thermally bond the composite auxiliary material layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate; cool the metal substrate with the composite auxiliary material layer, and obtain the all-waterborne coated metal composite coil after coiling. By constructing an all-waterborne coating system with water-based polyester primer, water-based hot melt adhesive, and water-based ink, the volatilization pollution of organic solvents in the oil-based paint is eliminated, the problems of flue gas emission and fire hazards in the traditional process are solved, the green environmental protection of the production process is realized, the production efficiency is improved, and complex textures such as high-precision wood grain and stone grain can be printed, breaking through the limitation of the single color of ordinary color-coated plates. By thermally pressing and bonding the composite auxiliary material layer with water-based hot melt adhesive and water-based ink to the metal substrate, the finished product has the functional properties of color-coated plates and laminated plates, and at the same time, the equipment capital investment is reduced in the production process, and the operation of personnel and equipment is reduced.

[0022] Next, the manufacturing process of an all-waterborne coated metal composite coil in this exemplary embodiment will be further described.

[0023] As described in step S110, sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer.

[0024] In an embodiment of the present application, the specific process of "sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer" described in step S110 can be further described in combination with the following description.

[0025] As described in the following steps, coat the water-based ink on one side of the PET protective layer to form a pattern layer; As described in the following steps, coat the water-based polyester primer on the side of the pattern layer away from the PET layer to form a primer layer; As described in the following steps, coat the water-based hot melt adhesive on the side of the primer layer away from the PET layer to form a hot melt adhesive layer, and obtain the composite auxiliary material layer including the pattern layer, the primer layer, the hot melt adhesive layer, and the PET layer.

[0026] As an example, the metal substrate can be made of one of stainless steel, galvanized sheet, aluminum sheet, and tinplate.

[0027] It should be noted that each coating of the present application uses water as the dispersion medium, adopts environmentally friendly materials and has no VOC emissions, avoiding the flammability and toxicity of traditional oil-based paints / glues; the water-based ink of the present application is a uniform paste composed of binder, environmentally friendly pigments, additives, etc., and can present high-precision patterns such as wood grain and stone grain through a printing roller, and there is no residual organic solvent after curing. The primer layer uses a water-based polyester resin primer. Compared with the oil-based primer, the VOC emissions are reduced, and the primer can be a water-based polyester white primer or other color primers according to requirements. The present application uses a water-based hot melt adhesive to replace the oil-based glue, and realizes the firm bonding of the PET composite layer and the metal substrate during subsequent hot pressing lamination, without additional adhesives.

[0028] In a specific embodiment, a PET film with a thickness of 10 - 35 μm is selected as the protective layer, and the water-based ink is printed on one surface of the PET protective layer, and a pattern layer with a thickness of 1 - 5 μm is formed after curing; the water-based polyester primer is uniformly coated on the side of the pattern layer away from the PET protective layer by a roller coating process, and a primer layer with a thickness of 3 - 10 μm is formed after high-temperature baking; finally, the water-based hot melt adhesive is coated on the side of the primer layer away from the PET layer to form a hot melt adhesive layer with a thickness of 5 - 20 μm, and a composite auxiliary material layer containing a PET layer, a pattern layer, a primer layer and a hot melt adhesive layer is finally obtained.

[0029] As described in step S120, the metal substrate is unrolled.

[0030] In an embodiment of the present application, the specific process of "unrolling the metal substrate" described in step S120 can be further described in combination with the following description.

[0031] As described in the following steps, the metal substrate is placed in an uncoiler for continuous unrolling; As described in the following steps, the unrolled metal substrate is preheated, and the preheating temperature is 100°C - 150°C.

[0032] In a specific embodiment, the rolled metal substrate is loaded onto an uncoiler and continuously unwound at a certain speed to ensure that the substrate is flat and has no creases; the unrolled metal substrate is preheated, and the temperature is controlled at 100°C - 150°C to remove trace moisture on the surface and improve the bonding force of subsequent coatings.

[0033] In an embodiment of the present application, before unrolling the metal substrate, it further includes: coating a water-based anti-corrosion material on the upper side of the metal substrate to form a passivation layer; coating a water-based anti-corrosion foaming material on the lower side of the metal substrate to form a back coating.

[0034] It should be noted that the stainless-steel substrate has excellent corrosion resistance by itself and does not require coating with anticorrosive materials. For easily oxidizable substrates such as galvanized sheets and tinplates, it is necessary to coat the upper and lower surfaces of the metal substrate with anticorrosive materials to seal the micropores on the metal surface, inhibit the formation of white rust on the zinc layer, and improve the salt spray resistance. In this application, a water-based foamable material is coated on the upper side of the substrate, such as NPCOAT-RC300 of Nippon Paint Co., Ltd., and a water-based anticorrosive foamable material is coated on the lower side of the substrate, such as the water-based back paint 2005B of Shenzhen Youwo New Materials Technology Co., Ltd. This coating has the characteristics of high hardness, stamping and bending resistance, good foamability and cold resistance. After foaming, it has the functions of anticorrosion, sound insulation and edge sealing, avoiding the problem of easy rusting of the cutting section of traditional coils. Moreover, the passivation layer and the back coating are pre-coated on the galvanizing production line, eliminating multiple pretreatment processes such as degreasing, cleaning, and chemical conversion of traditional color-coated plates.

[0035] In a specific embodiment, when the metal substrate is an easily oxidizable substrate, on the galvanizing production line, a Nippon RC300 water-based anticorrosive adhesion material is coated on the upper side of the substrate to form a passivation layer with a thickness of 0.2 μm to 2 μm, and a Youwo 2005B water-based anticorrosive foamable coating material is coated on the lower side of the substrate to form a back coating with a thickness of 3.0 μm to 7.0 μm.

[0036] As described in step S130, the composite auxiliary material layer is thermally bonded to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate.

[0037] In an embodiment of this application, the specific process of "thermally bonding the composite auxiliary material layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate" described in step S130 can be further described in combination with the following description.

[0038] As described in the following steps, the hot melt adhesive layer in the composite auxiliary material layer is oriented towards the metal substrate; As described in the following steps, the composite auxiliary material layer and the metal substrate are continuously hot-pressed and bonded at 150°C to 180°C through a film laminating roller, so that the composite auxiliary material layer and the metal substrate form an integrated composite structure.

[0039] In a specific embodiment, when the metal substrate is made of stainless steel, the hot melt adhesive layer of the composite auxiliary material layer is aligned with the upper surface of the preheated metal substrate, and is pressed by a heating roller in a laminating machine. The temperature of the heating roller is controlled at 150°C to 180°C, so that the composite auxiliary material layer and the metal substrate form an integrated composite structure; the composite structure includes a metal substrate, a hot melt adhesive layer, a primer layer, a pattern layer and a protective layer in sequence from bottom to top.

[0040] In a specific embodiment, when the metal substrate is an easily oxidizable material, align the hot melt adhesive layer of the composite auxiliary material layer with the upper surface of the preheated metal substrate with a passivation layer, and press and laminate it through a heating roller in a laminating machine. The temperature of the heating roller is controlled at 150°C to 180°C to form an integrated composite structure of the composite auxiliary material layer and the metal substrate; the composite structure sequentially includes a back coating, a metal substrate, a passivation layer, a hot melt adhesive layer, a primer layer, a pattern layer, and a protective layer from bottom to top. By thermally pressing and laminating the composite auxiliary material layer with the metal substrate, it replaces the multiple coating and baking of traditional color-coated plates and the oily glue lamination of laminated plates, further simplifying the production process and shortening the length of the production line.

[0041] As described in step S140, cool the metal substrate with the composite auxiliary material layer, and obtain the fully water-based coated metal composite coil after coiling.

[0042] In an embodiment of the present application, the specific process of "cooling the metal substrate with the composite auxiliary material layer and obtaining the fully water-based coated metal composite coil after coiling" described in step S140 can be further described in combination with the following description.

[0043] In a specific embodiment, please refer to Figure 2 , Figure 2 is a metal composite coil with a PET protective layer on the front. When the protective layer is a non-release film PET protective layer, cool the composite substrate after thermal pressing and lamination by air cooling on the front and water cooling on the back; after cooling, conduct a coating integrity inspection on the inspection platform. After passing the inspection, the composite substrate enters the coiling machine for coiling to obtain the finished product of the fully water-based coated metal composite coil.

[0044] When the PET protective layer in the composite auxiliary material layer is a release film, the specific process of "cooling the metal substrate with the composite auxiliary material layer and obtaining the fully water-based coated metal composite coil after coiling" described in step S140 can be further described in combination with the following description.

[0045] As described in the following steps, cool the metal substrate with the composite auxiliary material layer by air cooling and water cooling, and peel off the PET release film to obtain a preformed substrate; As described in the following steps, coat a water-based polyester topcoat and a back paint on the upper and lower sides of the preformed substrate respectively, and conduct high-temperature baking and curing. The curing plate temperature is 224°C to 241°C; As described in the following steps, cool down by air cooling and water cooling after baking, and obtain the fully water-based coated metal composite coil after coiling.

[0046] It should be noted that the substrate of the PET release film is PET, which is coated with silicone oil, so it is also called silicone oil film. The conventional thickness ranges from 25μm to 150μm. It is divided into cold and hot tear types and matte and glossy surfaces. After anti-static and scratch-proof treatments, the product has good adsorption and adhesion. When PET is used as the PET release film, the final product needs to peel off the release film, and a water-based polyester topcoat and a backcoat are respectively coated on the front and back of the substrate.

[0047] In a specific embodiment, please refer to Figure 3 , Figure 3 a metal composite coil with a water-based polyester topcoat protection layer on the front. Specifically, the composite substrate after hot pressing and laminating is cooled by air cooling on the front and water cooling on the back, and the PET release film is peeled off; a water-based polyester topcoat and a backcoat are respectively coated on the front and back of the preformed substrate by roll coating, and then high-temperature baking and curing are carried out, controlling the board surface temperature at 224 - 241°C; the substrate after high-temperature curing is cooled again by air cooling on the front and water cooling on the back, and finally the integrity of the coating is confirmed by an inspection platform, and the final all-water-based coating metal composite coil is obtained through winding.

[0048] This application also provides a metal composite coil prepared by the preparation method of the all-water-based coating metal composite coil according to the above, including a metal substrate, a hot melt adhesive layer, a primer layer, a pattern layer, and a protection layer; the hot melt adhesive layer is provided on the upper side of the metal substrate, the primer layer is provided on the upper side of the hot melt adhesive layer, the pattern layer is provided on the upper side of the primer layer, and the protection layer is provided on the upper side of the pattern layer.

[0049] As an example, the metal substrate includes stainless steel, galvanized sheet, aluminum sheet, tinplate, etc.

[0050] As an example, the protection layer is a PET protection layer or a topcoat protection layer.

[0051] In a specific embodiment, as Figure 2 shown, a metal substrate with a thickness of 0.3mm - 1.5mm is used for the metal substrate, and a hot melt adhesive layer, a primer layer, and a pattern layer are sequentially laminated on its surface, and the outermost layer is a PET protection layer; among them, the hot melt adhesive layer is composed of a water-based hot melt adhesive with a thickness of 1μm - 5μm; the primer layer is composed of a water-based polyester primer with a thickness of 3μm - 12μm; the pattern layer is composed of a water-based ink with a thickness of 1μm - 5μm; the PET protection layer is a transparent film with a thickness of 10μm - 35μm, and the topcoat protection layer is composed of a water-based polyester topcoat with a thickness of 3μm - 12μm.

[0052] In an embodiment of this application, the protection layer is a topcoat protection layer; a back coating is provided on the lower side of the metal substrate.

[0053] In a specific embodiment, when the PET protective layer is a release film, the release film needs to be peeled off during the preparation process, and the topcoat protective layer is used as the exposed protective layer on the front side, and the back coating is used as the exposed protective layer on the back side. Among them, the thickness of the topcoat layer is 3 μm to 12 μm, and the thickness of the back coating is 3 μm to 7 μm.

[0054] In an embodiment of the present application, it further includes a passivation layer and a back coating; the passivation layer is provided on one side of the metal substrate close to the hot melt adhesive layer, and the back coating is provided on one side of the metal substrate away from the hot melt adhesive layer.

[0055] In a specific embodiment, as Figure 2 shown, when the metal substrate is an easily oxidizable substrate, an anticorrosive material is further coated on the upper side of the metal substrate to form a passivation layer, and an anticorrosive material back coating is coated on the lower side. By coating the water-based anticorrosive material Libang RC300 on the upper side of the metal substrate, a water-based anticorrosive adhesion layer with a thickness of 0.2 μm to 2 μm is formed to seal the micropores on the surface of the substrate and improve the corrosion resistance; by coating the water-based anticorrosive foaming material Youwo 2005B on the lower side of the metal substrate, a water-based anticorrosive foaming coating with a thickness of 3 μm to 7 μm is formed, and the foaming expansion provides anticorrosion, sound insulation buffering and edge sealing functions. In this structure, a passivation layer, a hot melt adhesive layer, a primer layer, a pattern layer and a protective layer are sequentially laminated on the upper side of the metal substrate, and the lower side realizes functional protection through the back coating.

[0056] Table 1 and Table 2 are the front index parameters of the metal composite coil prepared by the above manufacturing process, and Table 3 is the back index parameter of the metal composite coil prepared by the above manufacturing process. It should be noted that the "front side" refers to the upper exposed coating surface of the metal composite coil, and the "back side" refers to the lower exposed coating surface of the metal composite coil.

[0057]

[0058] Table 1 Table 1 shows the front index parameters of the metal composite coil prepared by the manufacturing process of the present application in the embodiment where the front side is the topcoat protective layer.

[0059] The color difference detection adopts the standard plate comparison method. Before and after scraping the sample, it is required to be visually transparent and non-yellowing, and the color difference parameters are strictly limited to △L≤0.8, △a≤0.3, △b≤0.3 to ensure the color reproduction accuracy and batch consistency of the pattern. The glossiness is measured by a 60° gloss meter, and the target value is 35±5, meeting the appearance requirements in the fields of architecture and household appliances.

[0060] In terms of mechanical properties, in the T-bend test, the bending radius ≤ 1T, the pencil hardness reaches ≥ 3H without scratching, achieving the compatibility of high hardness and deep stamping formability. In the MEK wipe test, the coating is wiped repeatedly with methyl ethyl ketone solvent for ≥ 100 times without swelling or peeling, reflecting the crosslinking density and chemical resistance. In the packaging imprint test, simulating the transportation and storage conditions, a PE film is placed and pressed, and after being placed at 70 °C for 48 hours, there is no indentation on the plate surface.

[0061] The corrosion resistance is evaluated through the salt spray test. After making an X-shaped cut on the flat plate and testing for 240 hours, there are no rust spots on the surface and the rust diffusion ≤ 4 mm, reflecting the excellent anti-corrosion performance of the coating. In the acid and alkali resistance test, the sample is immersed in 5% hydrochloric acid and sodium hydroxide solution for 24 hours each, without obvious fading or blistering, proving the barrier ability of the coating to corrosive media. In the damp heat resistance test, it lasts for 48 hours in an environment of 60 °C and 98% humidity, the loss of gloss rate ≤ 8%, and the color difference △E ≤ 1.0, showing the light and color retention of the coating in extreme damp heat and its ability to adapt to extreme climate environments.

[0062] The UV resistance is tested by circulating light irradiation with a UVB-313 ultraviolet lamp for 24 hours, the loss of gloss rate ≤ 30%, and the color change △E ≤ 0.5, ensuring no yellowing or powdering during long-term outdoor use. In the stain resistance test, after writing with a water-based whiteboard pen and wiping with alcohol, there are no obvious marks on the coating, meeting the easy-cleaning requirements; in the dry heat resistance test, the 2T bent sheet is baked at 150 °C for 1 hour without cracking; the door seal tensile force and bright imprint test verify the bonding strength and surface indentation resistance under high-temperature compression conditions respectively.

[0063]

[0064] Table 2 Table 2 shows the front index parameters of the metal composite coil prepared by the manufacturing process of the present application in the embodiment with a PET protective layer on the front.

[0065] In the T-bend test, a bending machine is used to test the coiled material after laminating. After 0T bending of the coiled material after laminating, there is no cracking phenomenon, indicating the fitting stability of the coiled material during the stamping forming process. The cross-cut cupping test combines the 2×2 mm cross-cut method and the cupping test. The cupping depth reaches ≥ 7 mm, verifying the adhesion between the film layer and the substrate. After the test, there are no problems of detachment, wrinkling or film peeling, reflecting the ability of the coiled material to resist deformation.

[0066] The boiling water resistance test immerses the 1T bent sample and the flat plate in boiling water for continuous boiling for 1 hour. There are no blisters, delamination or color change in the coil material, proving its bonding reliability in high-temperature and high-humidity environments. The salt spray test simulates the corrosion conditions through a 5% sodium chloride neutral salt spray environment. After scribing, it lasts for ≥240 hours, and the rust diffusion width on both sides of the scratch edge is ≤4 mm, reflecting the long-term anti-corrosion performance of the coating. The stability test simulates the product storage conditions. After the coated board is taken off the production line, it is baked at 60°C for 48 hours and stored at room temperature for 3 months. All performance indicators (including T-bend, cupping, boiling water resistance and salt spray) remain stable, ensuring that the coil material still meets the application standards after long-distance transportation and long-term storage.

[0067]

[0068] Table 3 As shown in Table 3, Table 3 shows the back index parameters of the metal composite coil prepared by the manufacturing process of this application.

[0069] The color difference detection is measured by a color difference meter, and the judgment standard is △E≤0.5 to ensure the color uniformity of the back coating and its matching degree with the standard color plate. The T-bend test is carried out by the combined operation of a bending instrument and a flattening instrument. The bending radius is ≤4T, and there is no obvious cracking or glue peeling of the coating at the bending place. The pencil hardness test uses a Mitsubishi pencil and a pencil car to apply a pressure of ≥5H, and there are no scratches on the surface, reflecting the scratch resistance of the back coating.

[0070] The MEK test repeatedly wipes the coating surface with methyl ethyl ketone solvent for ≥100 times without swelling or peeling, proving the solvent resistance and crosslinking density of the coating. The salt spray resistance test is carried out through a neutral salt spray test. After the flat plate is edge-sealed, the test is continuously carried out for 120 hours, and there are no rust spots on the back surface, verifying the excellent anti-corrosion performance of the coating. The foaming property test evaluates the bonding performance between the back coating and the foaming material, and the affinity area is ≥98%, ensuring the bonding reliability between materials in the subsequent foaming process and avoiding delamination or degumming problems.

[0071] Although the preferred embodiments of the embodiments of this application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of this application.

[0072] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising said element.

[0073] The above provides a detailed introduction to a fully water-based coated metal composite coil and its manufacturing process. Specific examples are used in this text to elaborate on the principle and implementation of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A manufacturing process for a fully water-based coated metal composite coil, characterized in that, It includes the following steps: Sequentially coat water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer; Unroll the metal substrate; Thermocompression bond the composite auxiliary material layer to one side of the metal substrate; wherein, the PET protective layer is away from the metal substrate; Cool the metal substrate with the composite auxiliary material layer, and obtain the fully water-based coated metal composite coil after coiling; 2. The manufacturing process according to claim 1, characterized in that, The step of sequentially coating water-based ink, water-based polyester primer, and water-based hot melt adhesive on one side of the PET protective layer to form a composite auxiliary material layer includes: Coat the water-based ink on one side of the PET protective layer to form a pattern layer; Coat the water-based polyester primer on the side of the pattern layer away from the PET protective layer to form a primer layer; Coat the water-based hot melt adhesive on the side of the primer layer away from the PET protective layer to form a hot melt adhesive layer, and obtain the composite auxiliary material layer including the pattern layer, the primer layer, the hot melt adhesive layer, and the PET protective layer; 3. The manufacturing process according to claim 2, characterized in that, The step of thermocompression bonding the composite auxiliary material layer to the surface of the pre-heated metal substrate includes: Make the hot melt adhesive layer in the composite auxiliary material layer face the metal substrate; Continuously thermocompression bond the composite auxiliary material layer and the metal substrate at 150°C to 180°C through a laminating rubber roller, so that the composite auxiliary material layer and the metal substrate form an integrated composite structure; 4. The manufacturing process according to claim 3, characterized in that, The step of cooling the metal substrate with the composite auxiliary material layer and obtaining the fully water-based coated metal composite coil after coiling includes: Cool the metal substrate with the composite auxiliary material layer by air cooling and water cooling, and obtain the fully water-based coated metal composite coil after coiling; 5. The manufacturing process according to claim 3, characterized in that, The PET protective layer is a PET release film, and the step of cooling the metal substrate with the composite auxiliary material layer and obtaining the fully water-based coated metal composite coil after coiling includes: Cool the metal substrate with the composite auxiliary material layer by air cooling and water cooling, and peel off the PET release film to obtain a preformed substrate; Coat water-based polyester topcoat and back paint on the upper and lower sides of the preformed substrate respectively, and perform high-temperature baking and curing, and the curing plate temperature is 224°C to 241°C; Cool by air cooling and water cooling after baking is completed, and obtain the fully water-based coated metal composite coil after coiling; 6. The manufacturing process according to claim 1, characterized in that, Before unrolling the metal substrate, it further includes: Coat a water-based anti-corrosion material on the upper side of the metal substrate to form a passivation layer; Coat a water-based anti-corrosion and foamable material on the lower side of the metal substrate to form a back coating; 7. A metal composite coil manufactured by the manufacturing process according to claims 1-6, characterized in that, It includes a metal substrate, a hot melt adhesive layer, a primer layer, a pattern layer, and a protective layer; the hot melt adhesive layer is provided on the upper side of the metal substrate, the primer layer is provided on the upper side of the hot melt adhesive layer, the pattern layer is provided on the upper side of the primer layer, and the protective layer is provided on the upper side of the pattern layer; 8. The metal composite coil according to claim 1, wherein, It further includes a passivation layer and a back coating; the passivation layer is provided on the side of the metal substrate close to the hot melt adhesive layer, and the back coating is provided on the side of the metal substrate away from the hot melt adhesive layer; 9. The metal composite coil according to claim 1, characterized in that, The protective layer is a topcoat layer; the back coating is provided on the lower side of the metal substrate; 10. The metal composite coil according to claim 7, characterized in that, The thickness of the metal substrate is 0.3 mm to 1.5 mm; the thickness of the hot melt adhesive layer is 1 µm to 5 µm; the thickness of the primer layer is 3 µm to 12 µm; the thickness of the pattern layer is 1 µm to 5 µm.

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