Glued plate with high adhesive force and preparation method thereof

Abstract

The invention relates to the field of rubber plates, and particularly discloses a high-adhesion rubber coated plate and a preparation method thereof. The high-adhesion glued plate comprises a base plate, a first glue layer and a second glue layer, and the first glue layer is prepared from, by weight, 70-90 parts of water-based latex, 0.5-1.5 parts of dispersing agent, 0.5-1 part of defoaming agent, 0.5-1 part of preservative, 5-8 parts of tackifier, 10-30 parts of water and 5-8 parts of lithium silicate; the water-based latex, the lithium silicate and the tackifier are combined to form a firm silicon-oxygen-metal bond, so that the initial adhesion of an adhesive layer is improved, the layering phenomenon of the adhesive layer is reduced, the adhesive is easier to spread on the surface of an adhered object, and the adhesion effect between the adhesive layer and a substrate is improved.

Description

Technical Field

[0001] This application relates to the field of coated sheets, and in particular to a high-adhesion coated sheet and a method for preparing the same. Background Technology

[0002] Color-coated steel sheet is a corrosion-resistant, lightweight, and aesthetically pleasing steel material. It is typically made by pre-treating cold-rolled or galvanized steel sheets through surface treatments such as degreasing and passivation, followed by coating and high-temperature curing. This type of steel product leaves the factory with various attractive colors, hence the name "color-coated steel sheet," commonly referred to simply as "color steel sheet" or "color-coated plate" in my country. Color-coated steel sheets have a wide range of applications, increasingly replacing spray-painted sheets in the construction, interior decoration, and home appliance industries, and their application areas continue to expand.

[0003] As market demands for material performance and functionality continue to rise, coated steel sheets (hereinafter referred to as "coated sheets") using adhesives instead of traditional paints have emerged. Coated sheets achieve bonding, sealing, or other functional requirements through an extremely thin adhesive layer, typically 1-4 μm. However, in actual production and application, their process and structural characteristics also bring new technical challenges: The coated steel sheets are produced using a discontinuous production method. "Discontinuous production" refers to a process flow divided into two distinct stages: the first stage involves coating and curing the first adhesive layer, followed by winding, packaging, and even transportation; the second stage involves cross-linking or other surface treatments, followed by coating the second adhesive layer and curing. This segmented production method differs fundamentally from the traditional continuous "primer-curing-topcoat-curing" integrated process for color-coated steel sheets. Because the first adhesive layer is often fully cured after its initial curing, its surface activity is reduced, while the second adhesive layer requires intermediate steps such as winding, transportation, and storage, creating a significant physical and time interval between the two adhesive layers. This interval makes it difficult for the two adhesive layers to form sufficient chemical bonds and physical penetration, resulting in a significant decrease in interlayer adhesion. This makes delamination prone to occur during subsequent processing or use, affecting the integrity and reliability of the overall structure.

[0004] Therefore, overcoming the problem of decreased interlayer adhesion in discontinuous production has become a key challenge that urgently needs to be addressed in the development of coated sheet technology. Summary of the Invention

[0005] To improve the problems of the adhesive layer in existing coated sheets, this application provides a high-adhesion coated sheet and its preparation method.

[0006] In a first aspect, this application provides a high-adhesion coated sheet, which adopts the following technical solution: A high-adhesion coated sheet includes a substrate, a first adhesive layer, and a second adhesive layer. The first adhesive layer comprises the following raw materials in parts by weight: 70-90 parts of water-based latex, 0.5-1.5 parts of dispersant, 0.5-1 part of defoamer, 0.5-1 part of preservative, 5-8 parts of tackifier, 10-30 parts of water, and 5-8 parts of lithium silicate.

[0007] By employing the above technical solution, combining water-based latex and lithium silicate, a chemical reaction occurs with the substrate surface, forming strong silicon-oxygen-metal bonds. This generates a chemical adhesion force far exceeding that of physical adsorption. Simultaneously, it promotes good wetting and bonding forces between the first and second adhesive layers, reducing delamination. Lithium silicate enhances the surface hardness and scratch resistance of the adhesive layer, effectively blocking the penetration of moisture and corrosive media, and improving the stability of the adhesive layer. The combination of tackifier and water-based latex increases the initial tack of the adhesive layer, enhances the wettability of the water-based latex on the substrate, rapidly reduces the surface tension of the adhesive, facilitates easier spreading of the adhesive on the surface of the adhered object, generates rapid gripping force, and improves the adhesion between the adhesive layer and the substrate.

[0008] In the first adhesive layer system, water-based latex provides a flexible framework, while lithium silicate serves as an inorganic reinforcing phase. The hybridization of these two forms a composite adhesive film, giving the adhesive layer high cohesive strength, heat resistance, and durability. Through the chemical bonding of lithium silicate, the first adhesive layer forms a strong bond with the substrate, providing a highly active and robust adhesion structure for the subsequent second adhesive layer. This dual-layer adhesive structure not only firmly grips the metal substrate but also significantly increases the adhesion between the two layers, reducing delamination.

[0009] Preferably, the second adhesive layer comprises the following raw materials in parts by weight: 70-90 parts of aqueous latex, 5-20 parts of water, 3-5 parts of film-forming aid, and 0.3-0.5 parts of cellulose ether.

[0010] By adopting the above technical solution, using the same water-based latex for both the second and first adhesive layers can maintain good compatibility and bonding strength between the two layers, reducing the phenomenon of delamination between the second and first adhesive layers. Cellulose ether can increase the viscosity of the water-based latex, slow down the rate of water evaporation, promote cracking of the adhesive layer caused by excessively rapid drying, and improve the film-forming structural stability of the adhesive layer.

[0011] Preferably, the tackifier is rosin resin.

[0012] By adopting the above technical solution, adding rosin resin to the first adhesive layer can generate strong van der Waals forces and hydrogen bonds with the substrate, which can promote the rapid wetting and spreading of the adhesive on the substrate surface, quickly generate adhesion, and improve the adhesion effect of the adhesive layer.

[0013] Preferably, the film-forming aid is a dodecyl alcohol ester.

[0014] By adopting the above technical solution, dodecyl alcohol ester can promote the formation of a complete, smooth, and crack-free adhesive film in the second adhesive layer. At the same time, it can also evaporate after film formation, promoting the adhesive layer to restore good hardness and strength, and reducing the phenomenon of the adhesive film becoming soft and sticky.

[0015] Preferably, the aqueous latex is a composite of styrene-acrylic emulsion and chloroprene latex, wherein the mass ratio of styrene-acrylic emulsion to chloroprene latex is 1:(0.5-1).

[0016] By adopting the above technical solution, styrene-acrylic emulsion provides rigidity and skeletal strength, while chloroprene latex provides flexibility and elasticity. The resulting composite film can have strong cohesive strength, flexibility, and impact resistance, reducing the phenomenon of cracking or brittle failure of the adhesive layer when subjected to peeling or shear stress.

[0017] Preferably, the lithium silicate pre-modifies the aqueous latex, including the following specific steps: mixing sodium methylsilicate, lithium silicate, and water in advance, stirring evenly to obtain a silicate solution, then adding a silane coupling agent and mixing evenly to obtain a silicate sol, and mixing the silicate sol with the aqueous latex evenly to complete the modification of the aqueous latex by lithium silicate.

[0018] By adopting the above technical solution, sodium methylsilicate and lithium silicate are reacted in advance to form a lithium-sodium composite silicate prepolymer. The introduction of methyl groups can reduce the problem of excessive rigidity and brittleness of lithium silicate alone, thereby improving the flexibility and crack resistance of the adhesive film and enhancing its water resistance. Sodium methylsilicate, lithium silicate, and silane coupling agents can be uniformly distributed at the interface of latex particles at the nanoscale in the aqueous latex system, forming an inorganic network structure, improving the cohesive strength and wear resistance of the adhesive layer, effectively blocking the penetration of moisture and corrosive ions, and improving the water resistance, strength, and crack resistance of the adhesive layer.

[0019] Preferably, the mass ratio of sodium methylsilicate, lithium silicate, silane coupling agent and water is (1-2):6:(0.5-1):(15-20).

[0020] Preferably, the substrate is a steel plate.

[0021] Secondly, this application provides a method for preparing a high-adhesion coated sheet, which adopts the following technical solution: A method for preparing a high-adhesion coated sheet includes the following specific steps: S1 Uncoiling and Pre-treatment: The steel coil is uncoiled and pre-treated, including electrolytic degreasing and chemical degreasing, to obtain pre-treated strip steel. S2 Primer Coating: A primer is applied to the surface of the pretreated steel strip. The primer is either an epoxy primer or a polyurethane primer. S3 First Adhesive Layer Coating: Water-based latex, dispersant, defoamer, preservative, tackifier, water and lithium silicate are mixed and coated on the surface of the pretreated strip steel to form the first adhesive layer, resulting in the initial finished product; S4 First adhesive layer pre-curing: The initial finished product is pre-cured in the first oven to obtain a gel-state semi-finished product, wherein the gel-state semi-finished product has MEK > 1 and MEK ≤ 25; S5 Secondary coating pretreatment: The gel-state semi-finished product is rolled up and packaged, and then cross-linked to obtain a cross-linked product; S6 Second adhesive layer coating: A second adhesive layer is coated on the surface of the crosslinked product to obtain the pre-finished product; S7 Second adhesive layer curing: The pre-finished product is dried and cured in a second oven to obtain a high-adhesion coated board.

[0022] By adopting the above technical solution, generally speaking, the production of coated sheets is a phased and discontinuous process. In this application, discontinuous production means that the process of turning steel rolled hard coils into coated coils is not continuous. After the steel rolled hard coils are coated with the first adhesive layer, they need to be wound up, packaged, and removed from the production line as semi-finished coils, which are then transported to the cross-linking equipment for cross-linking treatment.

[0023] To prevent adhesion of the first adhesive layer in semi-finished rolls, existing technologies often involve completely drying the first adhesive layer. This leads to the loss of surface activity of the first adhesive layer, making it difficult for the first and second adhesive layers to form effective chemical bonds when the second adhesive layer is applied. This significantly weakens interlayer adhesion and makes delamination more likely. In other words, coated sheets often struggle to achieve both low adhesion and strong interlayer adhesion. This application addresses this issue by using a process where the first adhesive layer of the semi-finished roll is in a gel state. After unwinding the roll, minimal adhesion occurs on its surface, and the peel strength between the first and second adhesive layers is significantly improved during the application of the second adhesive layer. Specifically, the gel state in this application refers to a state where the first adhesive layer possesses the mechanical strength to prevent adhesion during winding and retains active chemical groups on its surface that can be used for secondary bonding. The specific criterion is a test of repeatedly wiping the surface of the first adhesive layer with methyl ethyl ketone (MEK) solvent, withstanding more than 1 MEK cycle and less than or equal to 25 cycles.

[0024] This ensures that the first adhesive layer has sufficient mechanical strength to support the coating of the second adhesive layer without being damaged, while leaving a large number of unreacted active groups on the surface. At this point, the adhesive layer is in a "gel state," possessing a certain mechanical strength to prevent adhesion while maintaining chemical activity. Applying the second adhesive layer: When the second adhesive layer is applied, the two adhesive layers will penetrate and fuse at the interface. In the final curing stage, the active groups in both adhesive layers participate in the cross-linking reaction together, and the chemical bonds will cross the original interface, completely curing together to form a continuous, uniform, and dense three-dimensional network structure.

[0025] Preferably, in step S4, the pre-curing temperature is 70-105℃ and the pre-curing time is 30-70s.

[0026] By adopting the above technical solution, the semi-finished roll is further precisely controlled in a special transitional gel state, ensuring that the first adhesive layer has sufficient mechanical strength to support the coating of the second adhesive layer without being damaged, while leaving a large number of unreacted active groups on the surface. If the pre-curing temperature is too low (<70℃) or the pre-curing time is too short (<30s), the number of MEK wiping cycles will be relatively small, resulting in incomplete curing and partial adhesion during packaging and winding. If the pre-curing temperature is too high (>105℃) or the pre-curing time is too long (>70s), the curing may be relatively complete, but the interlayer adhesion will be affected.

[0027] Preferably, in step S1, the running speed of the strip is 65-100 m / min.

[0028] By adopting the above technical solution and controlling the running speed of the strip, it is further ensured that the first adhesive layer and the second adhesive layer are uniformly coated on the surface of the strip. The uniform coating combined with precise control further ensures that the first adhesive layer is in an ideal gel state.

[0029] In summary, this application has the following beneficial effects: 1. Because this application uses water-based latex, lithium silicate, and tackifier to form strong silicon-oxygen-metal bonds, it improves the initial tack of the adhesive layer, promotes the formation of the first adhesive layer structure and the second adhesive layer to have good wetting and bonding forces, reduces the delamination of the adhesive layer, makes the adhesive easier to spread on the surface of the adhered object, and generates rapid gripping force, thereby improving the adhesion between the adhesive layer and the substrate.

[0030] 2. In this application, the first adhesive layer is baked to a gel state before being laminated with the second adhesive layer. This ensures that the first adhesive layer has sufficient mechanical strength to support the coating of the second adhesive layer without being damaged. At the same time, a large number of unreacted active groups remain on the surface. When the second adhesive layer is coated, the active groups in the two adhesive layers participate in the cross-linking reaction together to form a continuous, uniform, and dense three-dimensional network structure. This allows the two adhesive layers to grow together at the molecular level, forming a strong adhesive layer bonding interface and reducing the phenomenon of adhesive layer separation. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] All raw materials used in the examples are commercially available. Example Example 1

[0033] This embodiment provides a high-adhesion coated plate, comprising a substrate, a first adhesive layer, and a second adhesive layer. The substrate is a steel plate. The first adhesive layer comprises the following raw materials in parts by weight: 80 kg of water-based latex, 1 kg of dispersant, 0.8 kg of defoamer, 0.8 kg of preservative, 7 kg of tackifier, 20 kg of water, and 7 kg of lithium silicate. The second adhesive layer comprises the following raw materials in parts by weight: 80 kg of water-based latex, 15 kg of water, 4 kg of film-forming aid, and 0.4 kg of cellulose ether.

[0034] The film-forming aid is dodecyl alcohol ester, the cellulose ether is hydroxypropyl methylcellulose ether, the defoamer is BYK-022 silicone defoamer, the lithium silicate content is 25%, the modulus is 4.8, the dispersant is SN-5040 sodium polyacrylate, the preservative is BIT20N 1,2-benzisothiazolinone, and the tackifier is rosin resin purchased from Xinzhou Forestry Chemical Co., Ltd. GR923. The water-based latex is a composite of styrene-acrylic emulsion and chloroprene latex, with a mass ratio of styrene-acrylic emulsion to chloroprene latex of 1:0.5. The styrene-acrylic emulsion is BLJ-800, and the chloroprene latex is CRL-41F.

[0035] This embodiment provides a method for preparing a high-adhesion coated sheet, including the following specific steps: S1 Uncoiling and Pre-treatment: The steel coil is uncoiled and pre-treated, including electrolytic degreasing and chemical degreasing. The running speed of the strip is 80m / min, resulting in pre-treated strip.

[0036] S2 Primer Coating: Apply a primer to the pretreated steel strip surface. The primer is a polyurethane primer, numbered PMW10072.

[0037] S3 First Adhesive Layer Coating: Water-based latex, dispersant, defoamer, preservative, tackifier, water and lithium silicate are mixed and stirred evenly to obtain the first adhesive layer mixture, which is then coated on the surface of the pretreated strip steel to obtain the initial finished product.

[0038] S4 First Adhesive Layer Pre-curing: The initial finished product is pre-cured in the first oven at 85°C for 50 seconds to form a first adhesive layer with a thickness of 2μm, resulting in a gel-state semi-finished product. The MEK of the gel-state semi-finished product is 7 times.

[0039] S5 Secondary Coating Pretreatment: The gel-state semi-finished product is rolled up and packaged, and then cross-linked to obtain the cross-linked product.

[0040] S6 Second adhesive layer coating: Mix water-based latex, water, film-forming aid, and cellulose ether, stir evenly to obtain a second adhesive layer mixture, coat the surface of the crosslinked product with the second adhesive layer mixture to obtain a pre-finished product.

[0041] S6 Second Adhesive Layer Curing: The pre-finished product is dried and cured in a second oven to form a second adhesive layer with a thickness of 3μm, resulting in a high-adhesion coated board.

[0042] Example 2

[0043] The difference between Example 2 and Example 1 is that the first adhesive layer in the high-adhesion coated sheet includes the following raw materials in parts by weight: 70 kg of water-based latex, 1.5 kg of dispersant, 0.5 kg of defoamer, 0.5 kg of preservative, 5 kg of tackifier, 10 kg of water, and 5 kg of lithium silicate.

[0044] Example 3 The difference between Example 3 and Example 1 is that the first adhesive layer in the high-adhesion coated plate includes the following raw materials in parts by weight: 90 kg of water-based latex, 0.5 kg of dispersant, 1 kg of defoamer, 1 kg of preservative, 8 kg of tackifier, 30 kg of water, and 8 kg of lithium silicate.

[0045] Example 4 The difference between Example 4 and Example 1 is that the second adhesive layer in the high-adhesion coated plate includes the following raw materials in parts by weight: 70 kg of water-based latex, 5 kg of water, 3 kg of film-forming aid, and 0.5 kg of cellulose ether.

[0046] Example 5 The difference between Example 5 and Example 1 is that the second adhesive layer in the high-adhesion coated plate includes the following raw materials in parts by weight: 90 kg of water-based latex, 20 kg of water, 5 kg of film-forming aid, and 0.3 kg of cellulose ether.

[0047] Example 6 The difference between Example 6 and Example 1 is that the mass ratio of styrene-acrylic emulsion to chloroprene latex in the first adhesive layer of the high-adhesion coated sheet is 1:1.

[0048] Example 7 The difference between Example 7 and Example 1 is that the first adhesive layer in the high-adhesion coated sheet is modified with lithium silicate beforehand.

[0049] A method for preparing a high-adhesion coated sheet includes the following specific steps: S1 Uncoiling and Pre-treatment: The steel coil is uncoiled and pre-treated, including electrolytic degreasing and chemical degreasing. The running speed of the strip is 80m / min, resulting in pre-treated strip.

[0050] S2 Primer Coating: Apply a primer to the pretreated steel strip surface. The primer is a polyurethane primer, numbered PMW10072.

[0051] S3 First Adhesive Layer Coating: Sodium methylsilicate, lithium silicate, and water are mixed and stirred evenly to obtain a silicate solution. Then, a silane coupling agent is added and mixed evenly. The mass ratio of sodium methylsilicate, lithium silicate, silane coupling agent, and water is 1:6:1:15 to obtain a silicate sol. The silicate sol is mixed with water-based latex, dispersant, defoamer, preservative, tackifier, and water and stirred evenly to obtain the first adhesive layer mixture. This mixture is then coated on the surface of the pretreated strip steel to obtain the initial finished product.

[0052] S4 First Adhesive Layer Pre-curing: The initial finished product is pre-cured in the first oven at 85°C for 50 seconds to form a first adhesive layer with a thickness of 2μm, resulting in a gel-state semi-finished product. The MEK of the gel-state semi-finished product is 6 times.

[0053] S5 Secondary Coating Pretreatment: The gel-state semi-finished product is rolled up and packaged, and then cross-linked to obtain the cross-linked product.

[0054] S6 Second adhesive layer coating: Mix water-based latex, water, film-forming aid, and cellulose ether, stir evenly to obtain a second adhesive layer mixture, coat the surface of the crosslinked product with the second adhesive layer mixture to obtain a pre-finished product.

[0055] S7 Second Adhesive Layer Curing: The pre-finished product is dried and cured in a second oven to form a second adhesive layer with a thickness of 3μm, resulting in a high-adhesion coated board.

[0056] Example 8 The difference between Example 8 and Example 7 is that the mass ratio of sodium methylsilicate, lithium silicate, silane coupling agent and water is 2:6:0.5:20.

[0057] Example 9 The difference between Example 9 and Example 1 is that cellulose ether is not used in the second adhesive layer material in the high adhesion coated plate.

[0058] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that lithium silicate is not used in the first adhesive layer material of the high adhesion coated plate.

[0059] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no tackifier is used in the first adhesive layer material of the high adhesion coated plate.

[0060] Performance testing The high-adhesion coated plates provided in Examples 1-9 and Comparative Examples 1-2 of this application were subjected to the following performance tests, and the specific test results are shown in Table 1.

[0061] Detection methods I. Adhesion Test Referring to the cross-cut test standard in GB / T 9286—2021 "Paints and Varnishes - Cross-cut Test", a QFH type adhesion tester was used to test the adhesion effect of the high-adhesion coated board prepared in this application.

[0062] II. Hardness The hardness of the adhesive layer of the high-adhesion coated board prepared in this application was tested in accordance with the standard GB / T 6739—2006 "Determination of Hardness of Paint and Varnish Film by Pencil Method".

[0063] III. Impact Resistance The impact strength of the adhesive layer of the high-adhesion coated sheet prepared in this application was tested in accordance with the standard GB / T1843-2008 "Determination of impact strength of plastic cantilever beam".

[0064] Table 1: Performance Test Results Data Table

[0065] The performance test results show that the coated plate prepared in this application has good adhesion and maintains good strength. The first adhesive layer and the second adhesive layer have good bonding force, reducing the phenomenon of delamination.

[0066] A comparison of Examples 7-8 with Example 1 shows that pre-modifying the water-based latex with lithium silicate in Examples 7-8 improves the flexibility and crack resistance of the adhesive film, as well as the cohesive strength and abrasion resistance of the adhesive layer. A comparison of Example 9 with the Examples shows that the absence of cellulose ether in Example 9 significantly reduces the impact resistance of the coated sheet, further illustrating this point.

[0067] A comparison of Comparative Examples 1-2 and Example 1 shows that, in Comparative Example 1, lithium silicate was not used in the first adhesive layer material, and in Comparative Example 2, no tackifier was used in the first adhesive layer material. Performance testing results indicate that the adhesion, hardness, and impact resistance of the coated sheet significantly decreased. This further demonstrates that the tackifier and lithium silicate used in this application can interact with other components in the first adhesive layer system, improving the adhesion and strength of the adhesive layer.

[0068] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-adhesion coated sheet, characterized in that, It includes a substrate, a first adhesive layer and a second adhesive layer. The first adhesive layer includes the following raw materials in parts by weight: 70-90 parts of water-based latex, 0.5-1.5 parts of dispersant, 0.5-1 part of defoamer, 0.5-1 part of preservative, 5-8 parts of tackifier, 10-30 parts of water and 5-8 parts of lithium silicate.

2. The high-adhesion coated sheet according to claim 1, characterized in that, The second adhesive layer comprises the following raw materials in parts by weight: 70-90 parts of water-based latex, 5-20 parts of water, 3-5 parts of film-forming aid, and 0.3-0.5 parts of cellulose ether.

3. The high-adhesion coated sheet according to claim 2, characterized in that, The tackifier is rosin resin.

4. The high-adhesion coated sheet according to claim 2, characterized in that, The film-forming aid is a dodecyl alcohol ester.

5. The high-adhesion coated sheet according to claim 2, characterized in that, The aqueous latex is a composite of styrene-acrylic emulsion and chloroprene latex, wherein the mass ratio of styrene-acrylic emulsion to chloroprene latex is 1:(0.5-1).

6. The high-adhesion coated sheet according to claim 5, characterized in that, The modification of aqueous latex by lithium silicate includes the following specific steps: sodium methylsilicate, lithium silicate and water are mixed and stirred evenly to obtain a silicate solution, then a silane coupling agent is added and mixed evenly to obtain a silicate sol, and the silicate sol is mixed and stirred evenly with the aqueous latex to complete the modification of aqueous latex by lithium silicate.

7. The high-adhesion coated sheet according to claim 5, characterized in that, The mass ratio of sodium methylsilicate, lithium silicate, silane coupling agent and water is (1-2):6:(0.5-1):(15-20).

8. A method for preparing a high-adhesion coated sheet as described in any one of claims 1-7, characterized in that, The specific steps include the following: S1 Uncoiling and Pre-treatment: The steel coil is uncoiled and pre-treated, including electrolytic degreasing and chemical degreasing, to obtain pre-treated strip steel. S2 Primer Coating: A primer is applied to the surface of the pretreated steel strip. The primer is either an epoxy primer or a polyurethane primer. S3 First Adhesive Layer Coating: Water-based latex, dispersant, defoamer, preservative, tackifier, water and lithium silicate are mixed and coated on the surface of the pretreated strip steel to form the first adhesive layer, resulting in the initial finished product; S4 First adhesive layer pre-curing: The initial finished product is pre-cured in the first oven to obtain a gel-state semi-finished product, wherein the gel-state semi-finished product has MEK > 1 and MEK ≤ 25; S5 Secondary coating pretreatment: The gel-state semi-finished product is rolled up and packaged, and then cross-linked to obtain a cross-linked product; S6 Second adhesive layer coating: A second adhesive layer is coated on the surface of the crosslinked product to obtain the pre-finished product; S7 Second adhesive layer curing: The pre-finished product is dried and cured in a second oven to obtain a high-adhesion coated board.

9. The method for preparing a high-adhesion coated sheet according to claim 8, characterized in that, In step S4, the pre-curing temperature is 70-105℃ and the pre-curing time is 30-70s.

10. The method for preparing a high-adhesion coated sheet according to claim 8, characterized in that, In step S1, the running speed of the strip is 65-100 m / min.

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