Water-based two-component polyurethane primer-topcoat paint as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of coatings, and particularly relates to a water-based two-component polyurethane primer-topcoat paint and a preparation method and application thereof.The stirring kettle comprises a kettle body, a plurality of feeding ports are formed in the kettle body, a stirring device is arranged in the stirring kettle, the stirring device comprises a two-way stirring mode, the stirring device comprises a stirring cutter set, and the stirring cutter set is arranged in the kettle body. And a bidirectional driving structure. The two stirring cutter groups are arranged up and down along the height direction of the kettle body; the bidirectional driving structure is connected with the stirring cutter groups and is used for enabling the two stirring cutter groups which are arranged up and down to reversely rotate around the axis of the kettle body. According to the invention, the two groups of stirring cutter groups are arranged up and down, so that the vast majority of the height of the kettle body can be stirred, and in addition, the two groups of stirring cutter groups reversely rotate around the axis of the kettle body, so that two vortexes with different rotating directions can be formed between the two groups of stirring cutter groups, and liquid at the upper part and liquid at the lower part in the kettle body can be promoted to be quickly mixed; the mildness efficiency and the mixing quality are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a waterborne two-component polyurethane primer and topcoat in one and its preparation method and application. Background Art

[0002] With the country paying more and more attention to environmental protection work and the current development trend of low-carbon economy, the application of oil-based coatings with a very high content of volatile organic compounds (VOCs) in industry is subject to more and more stringent restrictions.

[0003] At present in the market, heavy truck engines mainly adopt a composite anti-corrosion coating system of oil-based primer plus topcoat to ensure the anti-corrosion performance of the engine. The double-coating matching of primer plus topcoat requires spraying twice during the production process, resulting in low construction efficiency; at the same time, issues such as the compatibility between the two coatings also need to be considered. In addition, due to the heavy truck engine being in a high-temperature environment for a long time, the corrosion of the equipment by high-intensity vibration and high-temperature corrosive liquids is accelerated, bringing many potential hazards to the safe production and application of automobiles. However, the anti-corrosion performance of the anti-corrosion coatings for heavy truck engines needs to be further improved at present. Summary of the Invention

[0004] The purpose of the present invention is to provide a waterborne two-component polyurethane primer and topcoat in one, its preparation method and application for the above-mentioned existing technical problems, achieving the effects of salt spray resistance, water resistance and high temperature resistance.

[0005] In view of this, the present invention provides a waterborne two-component polyurethane primer and topcoat in one, comprising component one and component two with a mass ratio of (3.4 - 4):1, wherein, component one comprises the following raw materials in parts by weight: 50 - 60 parts of modified hydroxyl acrylic resin, 0.1 - 1.0 part of defoamer, 1.0 - 3.0 parts of dispersant, 5 - 15 parts of coloring pigment, 5 - 20 parts of filler, 0.1 - 0.5 part of anti-settling agent, 0.5 - 1.5 parts of leveling agent, 0.2 - 1.5 parts of wetting agent, 5 - 15 parts of cosolvent, 0.4 - 0.6 part of adhesion promoter, 1 - 3 parts of corrosion inhibitor, 3 - 20 parts of water; the modified hydroxyl acrylic resin is a resin comprising epoxy groups, polyurethane groups and acrylic groups; Component two comprises the following raw materials in parts by weight: 60 - 80 parts of waterborne isocyanate curing agent, 20 - 40 parts of solvent.

[0006] In this technical solution, the waterborne two-component polyurethane primer and topcoat in one with the above ratio has salt spray resistance, water resistance and high temperature resistance.

[0007] Further, a preparation method of the waterborne two-component polyurethane primer and topcoat in one comprises the following steps: Step S1: Mix the modified hydroxyl acrylic resin, defoamer, dispersant, coloring pigment, filler, anti-settling agent, leveling agent, wetting agent, cosolvent, adhesion promoter, corrosion inhibitor and water in a stirring kettle to obtain Component 1; Step S2: Mix the waterborne isocyanate curing agent and solvent in a stirring kettle to obtain Component 2; Step S3: Mix the Component 1 and Component 2 to obtain the waterborne two-component polyurethane primer and topcoat in one.

[0008] Furthermore, the stirring kettle includes a kettle body, and a plurality of feeding ports are arranged on the kettle body. A stirring device is arranged in the stirring kettle. The stirring device includes a two-way stirring mode, and the stirring device includes: Stirring knife groups, and two groups of stirring knife groups are arranged up and down along the height direction of the kettle body; Two-way driving structure, the two-way driving structure is connected to the stirring knife groups and is used to make the two groups of stirring knife groups arranged up and down rotate reversely around the axis of the kettle body.

[0009] In this technical solution, by arranging two groups of stirring knife groups up and down, most positions in the height of the kettle body can be stirred. In addition, by making the two groups of stirring knife groups rotate reversely around the axis of the kettle body, two eddies with different rotation directions can be formed between the two groups of stirring knife groups, which can promote the rapid mixing of the liquid above and below in the kettle body and improve the mixing efficiency and mixing quality.

[0010] Furthermore, the two-way driving structure includes: A driving motor, the driving motor is fixedly arranged outside the kettle body, and a driving bevel gear is circumferentially and fixedly connected to the output end of the driving motor; A first rotating shaft, and a first bevel gear is fixedly connected to the outer periphery of the first rotating shaft; A second rotating shaft, and a second bevel gear is fixedly connected to the outer periphery of the second rotating shaft; Wherein, the first rotating shaft and the second rotating shaft coaxially pass through the second rotating shaft, both the first rotating shaft and the second rotating shaft extend into the kettle body, and stirring knife groups are arranged on the outer peripheries of the first rotating shaft and the second rotating shaft in the kettle body. The first bevel gear and the second bevel gear are arranged up and down and are both meshed with the driving bevel gear.

[0011] In this technical solution, when the driving motor is started to make the driving bevel gear rotate, the driving bevel gear will drive the first bevel gear and the second bevel gear to rotate synchronously and reversely. Then the first rotating shaft, the second rotating shaft and the stirring knife groups arranged on their outer peripheries in the kettle body will also rotate synchronously and reversely, thus realizing the two-way stirring mode.

[0012] Further, the stirring device includes the above-mentioned bidirectional stirring mode and also includes a unidirectional stirring mode. In the unidirectional stirring mode, two sets of stirring blade groups arranged up and down rotate in the same direction around the axis of the kettle body. There is also a switching structure for switching between the bidirectional stirring mode and the unidirectional stirring mode.

[0013] In this technical solution, the stirring is relatively intense in the bidirectional stirring mode, and heat will be generated during stirring. When it is necessary to ensure low temperature and temperature stability when the liquid mixture being stirred is mixed, there cannot be intense stirring. At this time, the unidirectional stirring mode can be switched to, so that the stirring kettle has both a bidirectional stirring mode and a unidirectional stirring mode, which can increase the application scenarios of the reaction kettle.

[0014] Further, the switching structure includes: a protrusion, which is provided on the outer wall of the first rotating shaft; a groove, which is provided on the inner wall of the second rotating shaft. The groove extends from one end of the second rotating shaft to the other end, and the groove matches the protrusion in shape and size; Among them, in the bidirectional stirring mode, the protrusion is located below the first rotating shaft and the first rotating shaft and the second rotating shaft can rotate relative to each other. In the unidirectional stirring mode, the protrusion moves upward and is inserted into the groove, and the first rotating shaft and the second rotating shaft are fixedly connected circumferentially.

[0015] In this technical solution, when it is necessary to switch the bidirectional stirring mode to the unidirectional stirring mode, the first rotating shaft is lifted upward along the axis direction of the first rotating shaft, so that the first bevel gear loses meshing with the driving bevel gear and the protrusion moves upward and is inserted into the groove. In this way, the first rotating shaft and the second rotating shaft can be fixedly connected circumferentially. Then, the driving motor is started to make the driving bevel gear rotate. The driving bevel gear can only drive the second bevel gear to rotate, so that the first rotating shaft and the second rotating shaft rotate circumferentially synchronously and in the same direction, realizing the unidirectional stirring mode. The first rotating shaft can be circumferentially rotatably connected and radially fixedly connected to the piston of the cylinder. When the mode needs to be switched, the piston of the driving cylinder is driven to expand and contract.

[0016] Further, the stirring blade group includes a plurality of blades, and auxiliary crushing structures are provided on the blades. The auxiliary crushing structures can assist the blades in crushing solid particles.

[0017] Further, the auxiliary crushing structure includes a receiving groove, which is arranged at one end of the blade away from the axis of the kettle body. In the receiving groove, there is: a crushing spring, which is perpendicular to the axis of the kettle body. One end of the crushing spring is fixedly connected to the bottom of the receiving groove, and the other end is connected to a crushing part. A sharp piercing part is provided at the outer end of the crushing part. The crushing spring always has a tendency to pull the crushing part into the receiving groove.

[0018] In this technical solution, under normal circumstances, the crushing part is located in the receiving groove. When the stirring device starts to work, under the action of centrifugal force, the crushing part resists the pulling force of the crushing spring and moves outward from the receiving groove, so that the piercing part pierces the solid particles in the kettle body. Subject to the impact resistance of the solid particles, the crushing part moves into the receiving groove, and then under the action of centrifugal force, it moves outward from the receiving groove to impact the solid particles, repeating the crushing in this way to achieve auxiliary blade mixing and stirring.

[0019] Furthermore, for the application of the water-based two-component polyurethane primer-sealer as a protective coating for heavy truck engines, the preferably applied thickness is 30 - 50 μm.

[0020] The beneficial effects of the present invention are as follows: 1. This water-based two-component polyurethane primer-sealer has salt spray resistance, water resistance, and high temperature resistance.

[0021] 2. By arranging two sets of stirring knife groups up and down, most positions in the height of the kettle body can be stirred. In addition, by rotating the two sets of stirring knife groups in opposite directions around the axis of the kettle body, two eddies with different swirling directions can be formed between the two sets of stirring knife groups, which can promote the rapid mixing of the liquid above and below in the kettle body, improving the stirring efficiency and mixing quality.

[0022] 3. In the two-way stirring mode, the stirring is relatively intense and heat is generated during stirring. When it is necessary to ensure low temperature and temperature stability when the liquid mixture being stirred is mixed, intense stirring cannot be carried out. At this time, it can be switched to the one-way stirring mode, enabling the stirring kettle to have a two-way stirring mode and a one-way stirring mode, which can increase the application scenarios of the reaction kettle. Description of the Drawings

[0023] Figure 1 is a perspective view of the present invention; Figure 2 is a top view of the present invention; Figure 3 is Figure 2 the sectional view A - A of Figure 4 is a schematic diagram of the stirring device; Figure 5 is Figure 4 the partial enlarged view B of The markings in the figures are shown as: 1. Kettle body; 2. Feeding port; 3. Stirring device; 4. Driving motor; 5. First rotating shaft; 6. Second rotating shaft; 7. Driving bevel gear; 8. First bevel gear; 9. Second bevel gear; 10. Stirring knife group; 11. Protrusion; 12. Groove; 13. Switching structure; 14. Blade; 15. Receiving groove; 16. Crushing spring; 17. Crushing part. Detailed Embodiments

[0024] The technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0025] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, rather than intending to limit the exemplary embodiments of the present application. For the convenience of description, the dimensions of each part shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0026] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such used data may be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same category, and do not limit the number of objects. For example, the first object may be one or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0027] It should be noted that in the description of the present application, the orientation or positional relationships indicated by the orientation terms such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present application; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0028] It should be noted that in this application, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising that element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0029] Example 1: A waterborne two-component polyurethane primer-sealer paint, comprising Component 1 and Component 2 with a mass ratio of (3.4 - 4):1. Among them, Component 1 includes the following raw materials in parts by weight: 50 - 60 parts of modified hydroxyl acrylic resin, 0.1 - 1.0 part of defoamer, 1.0 - 3.0 parts of dispersant, 5 - 15 parts of coloring pigment, 5 - 20 parts of filler, 0.1 - 0.5 part of anti-settling agent, 0.5 - 1.5 parts of leveling agent, 0.2 - 1.5 parts of wetting agent, 5 - 15 parts of co-solvent, 0.4 - 0.6 part of adhesion promoter, 1 - 3 parts of corrosion inhibitor, and 3 - 20 parts of water; the modified hydroxyl acrylic resin is a resin comprising epoxy groups, polyurethane groups and acrylic groups. Component 2 includes the following raw materials in parts by weight: 60 - 80 parts of waterborne isocyanate curing agent, and 20 - 40 parts of solvent.

[0030] The application of the waterborne two-component polyurethane primer-sealer paint as a heavy-duty truck engine protective coating, and the preferred coating thickness is 30 - 50 μm. The waterborne two-component polyurethane primer-sealer paint with the above ratio has salt spray resistance, water resistance and high temperature resistance.

[0031] Example 2: A preparation method of waterborne two-component polyurethane primer-sealer paint, comprising the following steps: Step S1: Mix the modified hydroxyl acrylic resin, defoamer, dispersant, coloring pigment, filler, anti-settling agent, leveling agent, wetting agent, co-solvent, adhesion promoter, corrosion inhibitor and water in a stirring kettle to obtain Component 1; Step S2: Mix the waterborne isocyanate curing agent and solvent in a stirring kettle to obtain Component 2; Step S3: Mix Component 1 and Component 2 to obtain the waterborne two-component polyurethane primer-sealer paint.

[0032] Example 3: As Figure 1-4 shown, the stirring kettle includes a kettle body 1, on which there are provided a plurality of feeding ports 2, and a stirring device 3 is arranged inside the stirring kettle. The stirring device 3 includes a two-way stirring mode, and the stirring device 3 includes a stirring blade group 10 and a two-way driving structure. The stirring blade group 10 is arranged in two groups up and down along the height direction of the kettle body 1; the two-way driving structure is connected to the stirring blade group 10 and is used to make the two groups of stirring blade groups 10 arranged up and down rotate in opposite directions around the axis of the kettle body 1. By arranging two groups of stirring blade groups 10 up and down, most positions in the height of the kettle body 1 can be stirred. In addition, making the two groups of stirring blade groups 10 rotate in opposite directions around the axis of the kettle body 1 can form two eddies with different swirling directions between the two groups of stirring blade groups 10, which can promote the rapid mixing of the liquid above and below in the kettle body 1 and improve the mixing efficiency and mixing quality.

[0033] As Figure 4 shown, the two-way driving structure includes a driving motor 4, a first rotating shaft 5 and a second rotating shaft 6. The driving motor 4 is fixedly arranged outside the kettle body 1, and a driving bevel gear 7 is circumferentially and fixedly connected to the output end of the driving motor 4; a first bevel gear 8 is fixedly connected to the outer periphery of the first rotating shaft 5; a second bevel gear 9 is fixedly connected to the outer periphery of the second rotating shaft 6; the first rotating shaft 5 and the second rotating shaft 6 coaxially pass through the second rotating shaft 6, and both the first rotating shaft 5 and the second rotating shaft 6 extend into the kettle body 1. Stirring blade groups 10 are arranged on the outer peripheries of the first rotating shaft 5 and the second rotating shaft 6 located in the kettle body 1. The first bevel gear 8 and the second bevel gear 9 are arranged up and down and are both meshed with the driving bevel gear 7.

[0034] Start the driving motor 4 to make the driving bevel gear 7 rotate, then the driving bevel gear 7 will drive the first bevel gear 8 and the second bevel gear 9 to rotate synchronously in opposite directions, and then the first rotating shaft 5 and the second rotating shaft 6 and the stirring blade groups 10 arranged on their outer peripheries located in the kettle body 1 will also rotate synchronously in opposite directions, thus realizing the two-way stirring mode.

[0035] The stirring device 3 includes the above two-way stirring mode and also includes a one-way stirring mode. In the one-way stirring mode, the two groups of stirring blade groups 10 arranged up and down rotate in the same direction around the axis of the kettle body 1. It also includes a switching structure 13 for switching between the two-way stirring mode and the one-way stirring mode. The stirring is more intense in the two-way stirring mode and heat will be generated during stirring. When it is necessary to ensure low temperature and temperature stability when the liquid mixture being stirred is mixed, there cannot be intense stirring. At this time, it can be switched to the one-way stirring mode. Enabling the stirring kettle to have a two-way stirring mode and a one-way stirring mode can increase the application scenarios of the reaction kettle.

[0036] AsFigure 4-5 As shown, the switching structure 13 includes a protrusion 11 and a groove 12. A protrusion 11 is provided on the outer wall of the first rotating shaft 5; a groove 12 is provided on the inner wall of the second rotating shaft 6. The groove 12 extends from one end of the second rotating shaft 6 to the other end, and the shape and size of the groove 12 match those of the protrusion 11. In the two-way stirring mode, the protrusion 11 is located below the first rotating shaft 5 and the first rotating shaft 5 and the second rotating shaft 6 can rotate relative to each other. In the one-way stirring mode, the protrusion 11 moves upward and is inserted into the groove 12, and the first rotating shaft 5 and the second rotating shaft 6 are fixedly connected in the circumferential direction.

[0037] When it is necessary to switch the two-way stirring mode to the one-way stirring mode, the first rotating shaft 5 is lifted upward along the axis direction of the first rotating shaft 5, so that the first bevel gear 8 loses meshing with the driving bevel gear 7 and the protrusion 11 moves upward and is inserted into the groove 12. In this way, the first rotating shaft 5 and the second rotating shaft 6 can be fixedly connected in the circumferential direction. Then, the driving motor 4 is started to make the driving bevel gear 7 rotate. The rotation of the driving bevel gear 7 can only drive the second bevel gear 9 to rotate, so that the first rotating shaft 5 and the second rotating shaft 6 rotate synchronously and in the same direction in the circumferential direction, realizing the one-way stirring mode. The first rotating shaft 5 can be circumferentially and rotatably connected to the piston of the cylinder and radially fixedly connected. When the mode needs to be switched, the piston of the driving cylinder can be telescoped.

[0038] Embodiment 4: As Figure 4 shown, the stirring blade group 10 includes a plurality of blades 14, and an auxiliary crushing structure is provided on the blades 14. The auxiliary crushing structure can assist the blades 14 in crushing solid particles. The auxiliary crushing structure includes a receiving groove 15. The receiving groove 15 is provided at one end of the blade 14 away from the axis of the kettle body 1. A crushing spring 16 is provided in the receiving groove 15. The crushing spring 16 is perpendicular to the axis of the kettle body 1. One end of the crushing spring 16 is fixedly connected to the bottom of the receiving groove 15, and the other end is connected to a crushing part 17. A sharp piercing part is provided at the outer end of the crushing part 17. The crushing spring 16 always has a tendency to pull the crushing part 17 into the receiving groove 15.

[0039] Normally, the crushing part 17 is located in the receiving groove 15. When the stirring device 3 starts to work, under the action of centrifugal force, the crushing part 17 resists the pulling force of the crushing spring 16 and moves outward from the receiving groove 15, so that the piercing part pierces the solid particles in the kettle body 1. Receiving the impact resistance of the solid particles, the crushing part 17 moves into the receiving groove 15, and then under the action of centrifugal force, it moves outward from the receiving groove 15 to impact the solid particles. This process is repeated for crushing, realizing the auxiliary mixing and stirring of the blades 14.

[0040] The embodiments of the present application have been described above in conjunction with the accompanying drawings. Without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application is not limited to the above specific implementation manners. The above specific implementation manners are merely illustrative rather than restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them fall within the protection scope of the present application.

Claims

1. A waterborne two-component polyurethane primer-sealer, characterized in that , including: It includes component one and component two with a mass ratio of (3.4 - 4):

1. Among them, component one includes the following raw materials in parts by weight: 50 - 60 parts of modified hydroxyl acrylic resin, 0.1 - 1.0 part of defoamer, 1.0 - 3.0 parts of dispersant, 5 - 15 parts of coloring pigment, 5 - 20 parts of filler, 0.1 - 0.5 part of anti-settling agent, 0.5 - 1.5 parts of leveling agent, 0.2 - 1.5 parts of wetting agent, 5 - 15 parts of cosolvent, 0.4 - 0.6 part of adhesion promoter, 1 - 3 parts of corrosion inhibitor, and 3 - 20 parts of water; the modified hydroxyl acrylic resin is a resin including epoxy group, polyurethane group, and acrylic group. Component two includes the following raw materials in parts by weight: 60 - 80 parts of waterborne isocyanate curing agent, and 20 - 40 parts of solvent.

2. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 1, characterized in that It includes the following steps: Step S1: Mix the modified hydroxyl acrylic resin, defoamer, dispersant, coloring pigment, filler, anti-settling agent, leveling agent, wetting agent, cosolvent, adhesion promoter, corrosion inhibitor, and water in a stirring kettle to obtain component one. Step S2: Mix the waterborne isocyanate curing agent and solvent in a stirring kettle to obtain component two. Step S3: Mix component one and component two to obtain the waterborne two-component polyurethane primer-sealer paint.

3. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 2, characterized in that, The stirring kettle includes a kettle body (1), multiple feeding ports (2) are arranged on the kettle body (1), a stirring device (3) is arranged in the stirring kettle, and the stirring device (3) includes a two-way stirring mode. The stirring device (3) includes: Stirring blade groups (10), and two groups of stirring blade groups (10) are arranged up and down along the height direction of the kettle body (1). A two-way driving structure, which is connected to the stirring blade groups (10) and is used to make the two groups of stirring blade groups (10) arranged up and down rotate in opposite directions around the axis of the kettle body (1).

4. The preparation method of a waterborne two-component polyurethane primer surfacer according to claim 3, characterized in that, The two-way driving structure includes: A driving motor (4), which is fixedly arranged outside the kettle body (1), and a driving bevel gear (7) is circumferentially and fixedly connected to the output end of the driving motor (4). A first rotating shaft (5), and a first bevel gear (8) is fixedly connected to the outer periphery of the first rotating shaft (5). A second rotating shaft (6), and a second bevel gear (9) is fixedly connected to the outer periphery of the second rotating shaft (6). Among them, the first rotating shaft (5) and the second rotating shaft (6) coaxially pass through the second rotating shaft (6), both the first rotating shaft (5) and the second rotating shaft (6) extend into the kettle body (1), stirring blade groups (10) are arranged on the outer peripheries of the first rotating shaft (5) and the second rotating shaft (6) located in the kettle body (1), and the first bevel gear (8) and the second bevel gear (9) are arranged up and down and both mesh with the driving bevel gear (7).

5. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 4, characterized in that, The stirring device (3) includes the above two-way stirring mode, and also includes a one-way stirring mode. In the one-way stirring mode, the two groups of stirring blade groups (10) arranged up and down rotate in the same direction around the axis of the kettle body (1), and a switching structure (13) for switching between the two-way stirring mode and the one-way stirring mode is also included.

6. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 5, characterized in that, The switching structure (13) includes: A protrusion (11), and the protrusion (11) is arranged on the outer wall of the first rotating shaft (5). A groove (12) is provided on the inner wall of the second rotating shaft (6). The groove (12) extends from one end of the second rotating shaft (6) to the other end, and the groove (12) matches the shape and size of the protrusion (11). Among them, in the two-way stirring mode, the protrusion (11) is located below the first rotating shaft (5) and the first rotating shaft (5) and the second rotating shaft (6) can rotate relative to each other. In the one-way stirring mode, the protrusion (11) moves upward and is inserted into the groove (12), and the first rotating shaft (5) and the second rotating shaft (6) are fixedly connected in the circumferential direction.

7. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 6, characterized in that, The stirring blade group (10) includes a plurality of blades (14), and an auxiliary crushing structure is provided on the blades (14), and the auxiliary crushing structure can assist the blades (14) to crush solid particles.

8. The preparation method of a waterborne two-component polyurethane primer-sealer paint according to claim 7, characterized in that, The auxiliary crushing structure includes a receiving groove (15). The receiving groove (15) is provided at one end of the blade (14) away from the axis of the kettle body (1). The following are provided in the receiving groove (15): A crushing spring (16). The crushing spring (16) is perpendicular to the axis of the kettle body (1). One end of the crushing spring (16) is fixedly connected to the bottom of the receiving groove (15), and the other end is connected to a crushing part (17). A sharp piercing part is provided at the outer end of the crushing part (17), and the crushing spring (16) always has a tendency to pull the crushing part (17) into the receiving groove (15).

9. Use of a water-based two-component polyurethane primer-sealer paint according to claim 1, characterized in that, Application of the water-based two-component polyurethane primer-sealer as a protective coating for heavy truck engines, and the preferably coating thickness is 30 - 50 μm.

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