Coating adhesive force testing method, vehicle and computer readable storage medium

Abstract

The embodiment of the invention provides a method for testing the adhesive force of a coating, a vehicle and a computer readable storage medium. The method for testing the adhesive force of the coating comprises the following steps: cutting an N * N matrix grid on the surface of the coating to form a scratch area; the test sample plate comprises a metal substrate and a coating attached to the surface of one side of the metal substrate; bending the scratch area inwards by 180 degrees along one side, far away from the coating, of the metal substrate to form a crease, so as to obtain a bent sample; soaking the bent sample in an alcohol solvent and then taking out to obtain a sample to be detected; stripping the adhesive tape at the crease of the sample to be detected, and observing the stripping of the coating; grading the adhesive force of the coating according to the peeling area of the coating so as to evaluate the adhesive force of the coating; the stripping area is in negative correlation with the adhesive force of the coating. The technical problem that in the prior art, the coating adhesive force and durability of the stainless steel material in the machining process are not detected is solved.

Description

Technical Field

[0001] This application relates to the field of metallurgical testing technology, and more specifically, to a method for testing coating adhesion, a vehicle, and a computer-readable storage medium. Background Technology

[0002] The exterior water deflector assembly of an automotive door (hereinafter referred to as the exterior water deflector) is a component used for door decoration, glass defrosting, water removal, dust removal, and clamping of the glass assembly. It is an important functional and decorative component of the automotive door system. Currently, automotive door exterior water deflector assemblies are typically made of bright aluminum alloy or bright stainless steel. These materials undergo specific processing and surface treatment to meet automotive decorative and functional requirements. However, traditional manufacturing methods, such as surface treatment of aluminum alloy exterior water deflectors, suffer from long processing steps and high costs, especially considering the need for surface treatment after profile processing. Therefore, using stainless steel as the base material and performing a surface treatment to achieve a high-gloss black effect has become a more cost-effective solution.

[0003] In the automotive industry, bright aluminum alloy and bright stainless steel are commonly used for exterior door trim. However, with the development of the automotive industry, the upgrading of consumption patterns, and the younger generation becoming the main consumers of cars, meeting consumers' personalized needs has become increasingly urgent. As consumers pursue personalization and sporty aesthetics in their vehicles, high-gloss black exterior door trim has become a trend to enhance the differentiation and modernity of vehicle appearance. High-gloss black exterior door trim with a sporty aesthetic is a key area for OEMs' differentiated development.

[0004] However, the high-gloss black coating on stainless steel substrates is susceptible to mechanical stress during processing, leading to decreased coating adhesion. While the commonly used cross-cut test can provide a preliminary assessment of coating adhesion, it suffers from poor discrimination when testing high-gloss black stainless steel and cannot accurately reflect the coating's performance under mechanical stress. Furthermore, the cross-cut test is insufficient for assessing the coating's durability under damaged conditions, failing to simulate the aging process during use, particularly the contact and reaction between the coating and solvents. This limits the comprehensiveness and reliability of the test.

[0005] Therefore, existing technologies lack a testing method that can effectively assess changes in coating adhesion during the processing of stainless steel materials, and also lack a testing scheme that can comprehensively evaluate the durability of the coating under damaged conditions. This not only affects the optimization of the manufacturing process of high-gloss black stainless steel exterior water deflectors for car doors, but also limits their performance evaluation in real-world usage environments.

[0006] There is currently no good solution to the above problems. Summary of the Invention

[0007] This application provides a method for testing coating adhesion, a vehicle, and a computer-readable storage medium to at least solve the technical problem that there is no method in the prior art for testing the coating adhesion and durability of stainless steel materials during processing.

[0008] According to one aspect of the embodiments of this application, a method for testing coating adhesion is provided, comprising the following steps:

[0009] S1, cut an N×N matrix grid on the coating surface of the test sample to form a scratch area; wherein, 6 ≤ N ≤ 15, the test sample includes a metal substrate and a coating attached to one side of the metal substrate.

[0010] S2, bend the scratched area 180° inward along the side of the metal substrate away from the coating to form a crease, and obtain a bent sample;

[0011] S3, after bending the sample and immersing it in an alcohol solvent, take it out to obtain the sample to be tested;

[0012] S4. Peel off the tape at the crease of the sample to be tested and observe the peeling of the coating.

[0013] S5. The adhesion of the coating is graded based on the area of ​​peeling off the coating to evaluate the coating adhesion; the area of ​​peeling off the coating is negatively correlated with the coating adhesion.

[0014] Furthermore, in step S1, 8 ≤ N ≤ 12.

[0015] Further, in step S1, the length of the test sample is 150mm~200mm; and / or, the width of the test sample is 30mm~50mm; and / or, the thickness of the test sample is 0.5mm~0.1mm; and / or, the thickness of the coating is >0 and ≤60μm.

[0016] Further, in step S1, cutting an N×N matrix grid on the coating surface of the test sample to form the scratch area includes the following steps:

[0017] S11, apply force with a cutting tool in a direction perpendicular to the coating surface until the coating is cut through to the metal substrate, forming N parallel cutting lines, and the distance between any two adjacent parallel cutting lines is 0.95mm~1.05mm.

[0018] S12, change the direction of the tool so that it is at 90° to the parallel cutting line, and repeat step S11 to form an N×N matrix grid on the coating surface to form the scratch area.

[0019] Further, in step S3, the alcohol solvent includes at least one of anhydrous ethanol, isopropanol, methanol, and acetone; and / or, the soaking time is 20 min to 30 min.

[0020] Furthermore, in step S4, peeling the tape off at the crease of the sample to be tested includes the following steps:

[0021] Apply tape to the crease, ensuring the length of the tape is parallel to the crease and covers the grid at the crease; then peel the tape off within 1.0s at an angle of 55° to 65° away from the crease.

[0022] The tape peeling was completed within 5 minutes of being removed from the alcohol solvent.

[0023] Further, in step S5, the adhesion of the coating is classified into five levels from high to low: level 0, level 1, level 2, level 3, level 4, and level 5. The classification is carried out in the following manner:

[0024] Grade 0: Smooth cut edges, no peeling;

[0025] Level 1: Peeling area ≤ 5%;

[0026] Level 2: Peeling area > 5% and ≤ 15%;

[0027] Level 3: Peeling area > 15% and ≤ 35%;

[0028] Level 4: Peeling area > 35% and ≤ 65%;

[0029] Level 5: Peeling area > 65%.

[0030] Furthermore, the coating includes at least one of polyurethane, acrylic, epoxy resin, and fluorocarbon resin; the metal substrate includes a stainless steel plate.

[0031] According to another aspect of the embodiments of this application, a vehicle is provided, comprising:

[0032] Memory, which stores executable programs;

[0033] A processor is used to run a program, in which the above-described coating adhesion test method is executed during program execution.

[0034] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is run, it controls the device where the storage medium is located to perform the above-described coating adhesion test method.

[0035] In this embodiment, by combining a two-factor test of bending stress change and resistance to anhydrous ethanol solvent, the adhesion performance of the coating under mechanical stress and alcohol solvent erosion can be effectively evaluated. Compared with the traditional cross-cutting method, the test method of this application can not only simulate the stress effect of the coating during actual processing, but also accelerate the failure of the coating interface through immersion in alcohol solvent, thereby effectively evaluating the adhesion and durability of the coating during processing. This effectively solves the problems in the prior art where the mechanical stress effect of the coating during processing cannot be accurately evaluated, and the aging durability test is insufficient when the coating is damaged. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0037] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] According to an embodiment of this application, an embodiment of a method for testing coating adhesion is provided. It should be noted that the steps shown in the flowchart can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0039] This embodiment provides a method for testing coating adhesion, including the following steps:

[0040] S1, cut an N×N matrix grid on the coating surface of the test sample to form a scratch area; wherein, 6 ≤ N ≤ 15, the test sample includes a metal substrate and a coating attached to one side of the metal substrate.

[0041] S2, bend the scratched area 180° inward along the side of the metal substrate away from the coating to form a crease, and obtain a bent sample;

[0042] S3, after bending the sample and immersing it in an alcohol solvent, take it out to obtain the sample to be tested;

[0043] S4. Peel off the tape at the crease of the sample to be tested and observe the peeling of the coating.

[0044] S5. The adhesion of the coating is graded based on the area of ​​peeling off the coating to evaluate the coating adhesion; the area of ​​peeling off the coating is negatively correlated with the coating adhesion.

[0045] Applying the technical solution of this embodiment, an N×N matrix grid is cut into the coating surface of the test sample to form a scratched area. This process simulates the cutting stress experienced by the coating during processing, exposing the coating's weaknesses. The subsequent 180° bending not only helps test the coating's flexibility and adhesion under extreme mechanical deformation but also simulates the stress changes the coating may encounter during actual processing. Immersing the bent sample in an alcohol solvent accelerates the swelling and dissolution process of the coating, simulating the coating's chemical resistance and aging process under damaged conditions. Especially for high-gloss black coatings on stainless steel substrates, alcohol solvent immersion accelerates the failure of the coating interface, aiding in subsequent evaluation of the coating's solvent resistance and adhesion. The tape peeling step is performed after the coating has undergone mechanical stress and chemical solvent treatment, providing a direct evaluation of the coating's durability and adhesion. Grading based on the area of ​​coating peeling allows for a quantitative assessment of coating adhesion, making the results more objective and accurate. Therefore, by combining mechanical stress variation and solvent testing, this application can more comprehensively evaluate the adhesion and durability of high-gloss black coatings on stainless steel substrates during actual processing and use. It effectively solves the problems in the prior art where the influence of mechanical stress on the coating during processing cannot be accurately evaluated, and the aging durability test is insufficient when the coating is damaged. This improves the accuracy and reliability of the test, and thus helps to select and optimize coating materials.

[0046] The matrix grid can be adjusted according to the coating thickness and the expected adhesion level. For example, in some embodiments, in step S1, 8 ≤ N ≤ 12. By controlling the range of N, it is helpful to more precisely detect the coating's mechanical stress resistance and its resistance to solvent erosion, further improving the accuracy of the detection. Specifically, N can be 8, 9, 10, 11, or 12, and correspondingly, in step S1, a matrix network of 8×8, 9×9, 10×10, 11×11, or 12×12 can be formed by cutting.

[0047] Step S1 of this application can be performed using a standard cutting tool (e.g., a cross-cutting tool). In some embodiments, step S1, cutting an N×N matrix grid on the coating surface of the test sample to form a scratch area, includes the following steps:

[0048] S11, apply force with a cutting tool in a direction perpendicular to the coating surface until the coating is cut through to the metal substrate, forming N parallel cutting lines, and the distance between any two adjacent parallel cutting lines is 0.95mm~1.05mm.

[0049] S12, change the direction of the tool so that it is at 90° to the parallel cutting line, and repeat step S11 to form an N×N matrix grid on the coating surface to form the scratch area.

[0050] In the above embodiments, by controlling the cutting depth to be consistent, penetrating the coating without damaging the metal substrate, the comprehensiveness and accuracy of the testing method are further enhanced.

[0051] In some embodiments, step S2 can use a bench vise with flat, smooth jaws or a dedicated bending device, which helps reduce additional coating damage during bending. For example, using a bench vise with flat, smooth jaws, clamp one end of the test sample and bend the test sample with the coating facing outwards towards the bend. Bend the test sample more than 90° in a continuous and uniform manner, continuing to bend the test sample until the bent end can be inserted into the jaws of the bench vise. Press the bench vise firmly to ensure that the inner surface of the bend of the test sample is in close contact, thereby achieving a 180° bend in the scratched area.

[0052] This application does not limit the size of the test sample, which can be adjusted according to actual needs. For example, in some embodiments, in step S1, the length of the test sample is 150mm~200mm; and / or, the width of the test sample is 30mm~50mm; and / or, the thickness of the test sample is 0.5mm~0.1mm; and / or, the coating thickness is >0 and ≤60μm. By controlling the size of the test sample to meet the above requirements, it helps to further improve the comparability and consistency of the test.

[0053] In some embodiments, in step S3, the alcohol solvent includes at least one selected from anhydrous ethanol, isopropanol, methanol, and acetone, wherein the mass fraction of ethanol in the anhydrous ethanol is ≥99.7%; and / or, the immersion time is 20 min to 30 min. By controlling the mass fraction of anhydrous ethanol, the influence of impurities on the coating can be reduced, further improving the accuracy of the test.

[0054] In some embodiments, in step S3, the bent sample is immersed in an alcohol solvent for 20 to 30 minutes and then removed. After removal, the residual alcohol is gently wiped clean with a clean cotton cloth to obtain the sample to be tested.

[0055] In some embodiments, step S4, peeling the tape at the crease of the sample to be tested, includes the following steps: applying the tape to the crease such that the length direction of the tape is parallel to the crease and the tape covers the grid at the crease; then peeling the tape at an angle of 55° to 65° away from the extension direction of the crease within 1.0 s; the tape peeling is completed within 5 min after removal from the alcohol solvent. 3M 600# tape can be used, with the center point of the tape applied to the crease. During application, to ensure good contact between the tape and the coating, the tape should be gently rubbed with the thumb to ensure it adheres tightly to the coating surface. Controlling the peeling angle and time helps reduce operational variables and further improves the accuracy of the test results. Peeling the tape at an angle of 55° to 65° away from the extension direction of the crease within 1.0 s means that the angle between the peeling direction of the tape and the crease surface is 55° to 65°. Specifically, when preparing to peel off the tape, one end of the tape adheres to the coated surface, and you pinch the other end of the tape with your fingers to begin tearing it off. At this time, the direction of your fingers forms an angle of 55° to 65° with the crease surface.

[0056] In step S4 of this application, the observation of peeling can be performed under a 5x to 10x magnifying glass, which helps to accurately record the degree of coating peeling and further improves the accuracy of the test results.

[0057] In some embodiments, in step S5, the adhesion of the coating is divided into five levels from high to low: level 0, level 1, level 2, level 3, level 4, and level 5. The grading is performed in the following manner:

[0058] Grade 0: Smooth cut edges, no peeling;

[0059] Level 1: Peeling area ≤ 5%;

[0060] Level 2: Peeling area > 5% and ≤ 15%;

[0061] Level 3: Peeling area > 15% and ≤ 35%;

[0062] Level 4: Peeling area > 35% and ≤ 65%;

[0063] Level 5: Peeling area > 65%.

[0064] In this application, the coating adhesion is classified into six levels from high to low: Level 0, Level 1, Level 2, Level 3, Level 4, and Level 5. This grading method helps to provide a more accurate standard for evaluating coating quality. Specifically, Level 0 indicates a smooth cut edge with no coating peeling, meaning the adhesion between the coating and the substrate is the strongest. As the level increases, the degree of coating peeling gradually increases, until Level 5, where the peeling area exceeds 65%, directly reflecting a significant decrease in coating adhesion. By defining the above detailed grading method, the reliability of the test results can be further improved.

[0065] This application does not limit the specific type of test sample. For example, in some embodiments, the coating includes at least one of polyurethane, acrylic, epoxy resin, and fluorocarbon resin; the metal substrate includes a stainless steel plate.

[0066] Embodiments of this application also provide a vehicle, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the methods described in various embodiments of this application when it runs.

[0067] Embodiments of this application also provide a computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the computer-readable storage medium is located to perform the methods of various embodiments of this application.

[0068] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0069] Example 1

[0070] The coating adhesion test method in this embodiment includes the following steps:

[0071] S1, Take PCM test sample A from manufacturer A, including a stainless steel substrate and a fluorocarbon resin coating attached to one side of the stainless steel substrate; the test sample A is 150mm long, 30mm wide, 0.7mm thick, and the coating thickness is 30 micrometers.

[0072] The cross-cut test was performed using a QFH-A 1mm cross-cutting tool. A set of parallel cut lines were created on test sample A by applying vertical force to the coating and then to the stainless steel substrate. All cut lines penetrated to the metal substrate. This process was repeated, with another set of intersecting parallel lines drawn at a 90° angle to the original set, resulting in a 10×10 grid to form the scratch area. A soft brush was then used to gently sweep backwards and forwards several times along each diagonal of the grid pattern.

[0073] S2, clamp the long end of the test sample with a bench vise with flat and smooth jaws and make the coated surface of the test sample face the outside of the bend. Bend the test sample more than 90° in a continuous and uniform manner. Continue to bend the test sample until the bent end can be inserted into the jaws of the bench vise. Press the bench vise to ensure that the test sample surfaces on the inside of the bend are in close contact, so that the coated surface of the scratch area is bent 180° to obtain the bent sample.

[0074] S3. Place the bent sample in anhydrous ethanol (mass fraction ≥99.7%) solvent, soak for 25±5 min and then take it out. After taking it out, gently wipe the residual alcohol off the sample with a clean cotton cloth to obtain the sample to be tested.

[0075] S4. Apply 3M 600# adhesive tape to the center of the bend of the sample to be tested, parallel to the bend. The tape should completely cover the grid at the bend. Then, press the tape flat at the bend with your fingers and gently rub the tape with your thumb to make it adhere tightly to the coating surface. Hold the sample with one hand and hold one end of the tape with the other hand. At an angle of approximately 60°, smoothly peel off the tape within 1.0 second. Repeat the application and removal of the tape three times to obtain the test results. Complete the adhesion and pull-out test within 5 minutes. Visually inspect the coating peeling at the bend with the aid of a magnifying glass.

[0076] S5, based on the area of ​​coating peeling, the adhesion of the coating is graded as follows:

[0077] Grade 0: Smooth cut edges, no peeling;

[0078] Level 1: Peeling area ≤ 5%;

[0079] Level 2: Peeling area > 5% and ≤ 15%;

[0080] Level 3: Peeling area > 15% and ≤ 35%;

[0081] Level 4: Peeling area > 35% and ≤ 65%;

[0082] Level 5: Peeling area > 65%. Results are shown in Table 1.

[0083] Example 2

[0084] The difference from Example 1 is that test sample A is replaced with PCM test sample B manufactured by manufacturer B.

[0085] Example 3

[0086] The difference from Example 1 is that test sample A is replaced with PCM test sample C manufactured by manufacturer C.

[0087] Table 1

[0088]

[0089] As shown in Table 1, the test method provided in the embodiment can be used to test the test sample with obvious discrimination, which helps to improve the upper limit of adhesion detection. The test method of this application is applicable to the testing of stainless steel plates currently covered with high gloss black, with good discrimination and high test accuracy.

[0090] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for testing coating adhesion, characterized in that, Includes the following steps: S1, cut an N×N matrix grid on the coating surface of the test sample to form a scratch area; wherein, 6 ≤ N ≤ 15, the test sample includes a metal substrate and a coating attached to one side of the surface of the metal substrate; S2, bend the scratched area inward along the side of the metal substrate away from the coating by 180° to form a crease, and obtain a bent sample; S3, the bent sample is immersed in an alcohol solvent and then taken out to obtain the sample to be tested; S4, peel off the tape at the crease of the sample to be tested and observe the peeling of the coating; S5, The adhesion of the coating is graded according to the peeling area of ​​the coating to evaluate the adhesion of the coating; the peeling area is negatively correlated with the adhesion of the coating.

2. The method for testing coating adhesion according to claim 1, characterized in that, In step S1, there are 8 ≤ N ≤ 12.

3. The method for testing coating adhesion according to claim 1, characterized in that, In step S1, the length of the test sample is 150mm~200mm; and / or, the width of the test sample is 30mm~50mm; and / or, the thickness of the test sample is 0.5mm~0.1mm; and / or, the thickness of the coating is >0 and ≤60μm.

4. The method for testing coating adhesion according to claim 1, characterized in that, Step S1, cutting an N×N matrix grid on the coating surface of the test sample to form the scratch area, includes the following steps: S11, apply force with a cutting tool in a direction perpendicular to the coating surface until the coating is cut through to the metal substrate, forming N parallel cutting lines, and the distance between any two adjacent parallel cutting lines is 0.95mm~1.05mm. S12, change the direction of the tool so that it is at 90° to the parallel cutting line, and execute step S11 again to form an N×N matrix grid on the coating surface to form the scratch area.

5. The method for testing coating adhesion according to any one of claims 1 to 4, characterized in that, In step S3, the alcohol solvent includes at least one of anhydrous ethanol, isopropanol, methanol, and acetone; and / or, the soaking time is 20 min to 30 min.

6. The method for testing coating adhesion according to any one of claims 1 to 5, characterized in that, Step S4, peeling the tape off at the crease of the sample to be tested, includes the following steps: Apply tape to the crease so that the length of the tape is parallel to the crease and the tape covers the grid at the crease; then peel the tape off within 1.0s at an angle of 55° to 65° away from the extension direction of the crease. The tape peeling is completed within 5 minutes after removal from the alcohol solvent.

7. The method for testing coating adhesion according to any one of claims 1 to 6, characterized in that, In step S5, the adhesion of the coating is divided into five levels from high to low: level 0, level 1, level 2, level 3, level 4, and level 5. The grading is carried out in the following manner: Grade 0: Smooth cut edges, no peeling; Level 1: Peeling area ≤ 5%; Level 2: Peeling area > 5% and ≤ 15%; Level 3: Peeling area > 15% and ≤ 35%; Level 4: Peeling area > 35% and ≤ 65%; Level 5: Peeling area > 65%.

8. The method for testing coating adhesion according to any one of claims 1 to 7, characterized in that, The coating comprises at least one of polyurethane, acrylic, epoxy resin, and fluorocarbon resin; the metal substrate comprises a stainless steel plate.

9. A vehicle, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, executes the coating adhesion test method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored executable program, wherein, when the executable program is executed, it controls the device on which the storage medium is located to perform the coating adhesion test method according to any one of claims 1 to 8.

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