A method of determining the hiding power of a color paint

Abstract

The application provides a method for determining the hiding power of color paint, relates to the field of paint technology, and comprises the following steps: spraying a test plate, a film thickness plate and a black-and-white check test paper with a color paint to be measured along a first direction, wherein the test plate, the film thickness plate and the black-and-white check test paper are located on a spraying track of the color paint to be measured; spraying along the spraying track in a single spraying operation process; the color value of the test plate corresponding to a reference line is a reference color value, the reference line is a boundary line between a region covered by the color paint to be measured and a region not covered by the color paint to be measured on the black-and-white check test paper, a test region is located on a side of the reference line away from the spraying track, a plurality of color value measuring points are taken in a second direction perpendicular to the first direction in the test region of the test plate, and a color difference value between each color value measuring point and the reference color value is measured respectively; and based on the color difference value and a preset color difference value, an engineering hiding power line extending along the first direction is determined to obtain an engineering hiding power film thickness. The method is simple, convenient to operate and high in efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to a method for determining the hiding power of color paint. BACKGROUND

[0002] With the popularization of automobiles and the explosive development of new energy vehicles, customers have higher requirements for vehicle body color and paint surface texture. In order to meet the requirements of customers for personalized and customized colors, a large number of new effect materials that can be used for vehicle body spraying have emerged in the market to make the paint surface have the effects of flashing, permeability, etc., such as presenting pearlescent, color aluminum materials, etc. The color hiding power is different from the traditional aluminum powder coating or solid color paint, so it is particularly important to accurately test and evaluate the hiding power of new effect materials.

[0003] Currently, the hiding power of color paint is mainly detected by referring to the black and white grid spraying method in GB / T23981.2-2023. This method requires multiple spraying, repeated observation of the black and white grid masking state, and finally weighing and calculating after baking. This test method is time-consuming, and the consistency of multiple spraying is high, which is easy to produce errors. Based on the above-mentioned black and white grid spraying method, there is a tape masking layering spraying method. This method forms a film thickness ladder after spraying, and the black and white grid hiding power and engineering hiding power are determined by visual observation and instrument determination. Although the tape masking layering spraying method shortens the test time to a certain extent, the layering operation is relatively complicated, and the consistency requirement of multiple spraying is not reduced. At the same time, the film thickness ladder state is artificially created, which changes abruptly, and the precision of the hiding power test result is limited. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for determining the hiding power of color paint, which solves the problem that the method for detecting the hiding power of color paint in the prior art is relatively complicated.

[0005] To achieve the above-mentioned purposes and other related purposes, the present application provides a method for determining the hiding power of color paint, comprising:

[0006] Spray the test plate, film thickness plate and black and white grid test paper with the color paint to be tested along the first direction, wherein the test plate, film thickness plate and black and white grid test paper are located on the spraying track of the color paint to be tested;

[0007] During a single spraying operation, spray along the spraying track in one direction. After a single spraying operation is completed, observe the black and white grid test paper. If the black and white grid test paper located in the hiding area on the spraying track includes at least one complete black grid and one complete white grid, stop spraying. Otherwise, continue spraying.

[0008] The test plate corresponds to a reference color value on a reference line, the reference line being a boundary line between a region covered by the color paint to be tested and a region not covered by the color paint to be tested on the black-and-white test paper, the film thickness plate and the test plate each have a test area, the test area being located on a side of the reference line away from the spraying trajectory, a plurality of color value measurement points are taken in a second direction perpendicular to the first direction in the test area of the test plate, and a color difference value between each of the color value measurement points and the reference color value is measured respectively, based on the color difference value and a preset color difference value, an engineering hiding power line extending in the first direction is determined to obtain an engineering hiding power film thickness.

[0009] In an exemplary embodiment, the film thickness of the color paint to be tested on the reference line of the film thickness plate is a black-and-white hiding power film thickness.

[0010] In an exemplary embodiment, based on the color difference value and the preset color difference value, an engineering hiding power line extending in the first direction is determined to obtain an engineering hiding power film thickness, comprising:

[0011] When the color difference value between the color value measurement point and the reference color value is greater than the preset color difference value, the color value measurement point is taken on the test plate in the second direction towards the reference line;

[0012] When the color difference value between the color value measurement point and the reference color value is less than the preset color difference value, the color value measurement point is taken on the test plate in the second direction away from the reference line;

[0013] When the color difference value between the color value measurement point and the reference color value is equal to the preset color difference value, a straight line of the film thickness plate and the test plate passing through the color value measurement point in the first direction is the engineering hiding power line, and the film thickness of the color paint to be tested on the engineering hiding power line of the film thickness plate is an engineering hiding power film thickness.

[0014] In an exemplary embodiment, a black-and-white test paper in a long strip shape extending in the second direction is arranged on the film thickness plate, the length of the black-and-white test paper in the second direction is greater than or equal to the length of the film thickness plate in the second direction, and the width of the black-and-white test paper in the first direction is less than the width of the film thickness plate in the first direction.

[0015] In an exemplary embodiment, before the test plate, the film thickness plate and the black-and-white test paper are sprayed with the color paint, comprising:

[0016] A preparation process before the test plate is sprayed with the color paint, the preparation process comprising spraying a middle coating.

[0017] In an exemplary embodiment, after the spraying is stopped, before a plurality of color value measurement points are taken in the test area of the test plate, comprising:

[0018] The finishing process after the paint spraying of the test plate includes varnish spraying and drying.

[0019] The film thickness plate and the black and white test paper are dried.

[0020] In an exemplary embodiment, the test plate and the film thickness plate are rectangular, the width direction of the film thickness plate and the test plate extends along the first direction, and the length direction of the film thickness plate and the test plate extends along the second direction.

[0021] In an exemplary embodiment, the spraying track coincides with the center line of the film thickness plate, and the center line extends along the first direction.

[0022] In an exemplary embodiment, the film thickness plate is equal in length to the test plate.

[0023] In an exemplary embodiment, the length of each grid of the black and white test paper in the length direction of the film thickness plate is 1 cm to 2.5 cm.

[0024] In an exemplary embodiment, the test plate and the film thickness plate are automatically sprayed by a rotary cup or a spray gun.

[0025] As described above, the method for determining the paint hiding power of the present application has the following beneficial effects:

[0026] By spraying the film thickness plate and the test plate along the first direction, the film thickness of the paint to be measured on the film thickness plate and the test plate has a uniform change in the second direction, and more accurate film thickness data can be obtained when determining the engineering hiding power of the paint. Meanwhile, compared with the traditional method, the method for determining the paint hiding power is simpler to operate and has higher efficiency, and has good industrial promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 FIG. 1 shows the arrangement position of the film thickness plate, the black and white test paper, and the test plate according to an embodiment of the present application.

[0028] Figure 2 FIG. 2 shows the flowchart of the method for determining the paint hiding power according to an embodiment of the present application.

[0029] Figure 3 FIG. 3 shows the change of the paint film thickness during spraying according to an embodiment of the present application.

[0030] Label explanation: 1, film thickness plate; 2, black and white test paper; 3, test plate; 4, engineering hiding power line; 5, reference line; 6, spraying track; 7, test area. DETAILED DESCRIPTION

[0031] Following, the advantages and effects of the present application will be apparent to those skilled in the art from the disclosure hereof. The present application can be implemented or applied in other different embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0032] Referring to Figures 1 to 3 It is to be noted that the drawings provided in the embodiments only schematically illustrate the basic concepts of the present application, and thus the drawings only show the components related to the present application, rather than the number, shape and size of the components in actual implementation. The shapes, number and proportions of the components in actual implementation can be arbitrarily changed, and the layout of the components can be more complex. The structures, proportions and sizes shown in the drawings are only used to understand and read the disclosed content by those skilled in the art, and do not limit the conditions for implementing the present application, and thus do not have technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes of the present application, should still fall within the scope of the disclosed technology. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" in the specification are only for the convenience of understanding and reading, and do not limit the scope of the present application. The change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present application.

[0033] As shown in Figure 1 and Figure 2 The present application provides a method for measuring the hiding power of color paint, comprising:

[0034] Step S110: spraying the test plate 3, the film thickness plate 1 and the black and white test paper 2 with the color paint to be measured in the first direction, and the test plate 3, the film thickness plate 1 and the black and white test paper 2 are all located on the spraying track 6 of the color paint to be measured.

[0035] In an exemplary embodiment, the test plate 3 and the film thickness plate 1 are both rectangular, the width direction of the film thickness plate 1 and the test plate 3 extends along the first direction, and the length direction of the film thickness plate 1 and the test plate 3 extends along the second direction. The black-and-white check test paper 2 is arranged on the film thickness plate 1 in the form of a long strip extending along the second direction, the length of the black-and-white check test paper 2 in the second direction is greater than or equal to the length of the film thickness plate 1 in the second direction, the width of the black-and-white check test paper 2 in the first direction is less than the width of the film thickness plate 1 in the first direction, and the black-and-white check test paper 2 has at least one black check and one white check in the first direction. The rectangular test plate 3 and the film thickness plate 1 have regular shapes, which facilitates production and facilitates finding the corresponding positions between the test plate 3 and the film thickness plate 1 to determine the black-and-white check hiding power film thickness and the engineering hiding power film thickness. It should be noted that the line connecting the "corresponding positions" of the test plate 3 and the film thickness plate 1 in the above extends along the first direction. The shape of the test plate 3 and the film thickness plate 1 can be adjusted according to testing needs. In an exemplary embodiment, the black-and-white check test paper 2 is pasted on the film thickness plate 1. In another exemplary embodiment, the black-and-white check test paper 2 is pinned on the film thickness plate 1 using a drawing pin. By arranging the black-and-white check test paper 2 on the film thickness plate 1, the placement part for placing the black-and-white check test paper 2 can be reduced, the testing steps can be simplified, and the hiding condition on the black-and-white check test paper 2 can be easily matched with the film thickness plate 1 and the test plate 3. The manner of arranging the black-and-white check test paper 2 on the film thickness plate 1 can be adjusted according to specific testing needs.

[0036] In an exemplary embodiment, the material of the test plate 3 is an electrophoresed steel plate or a galvanized plate or an aluminum plate. The material of the test plate 3 should be the same as that of the painted vehicle and be electrophoresed to present a real effect close to the actual spraying scenario.

[0037] Step S120: During a single spraying operation, spraying is performed along the spraying track 6 in one direction, and after the single spraying operation is completed, the black-and-white check test paper 2 is observed. If the black-and-white check test paper 2 located in the hiding area on the spraying track 6 includes at least one complete black check and one complete white check, spraying is stopped, otherwise, spraying is continued.

[0038] It should be noted that the "hiding area" described above is an area in which the background color of the black-and-white check test paper 2 cannot be seen, and the spraying amount is uniform in each spraying operation.

[0039] In an exemplary embodiment, the black-and-white check test paper 2 has at least one black check and one white check in the first direction.

[0040] In an exemplary embodiment, the length of each grid of the black-and-white grid test paper 2 in the length direction of the film thickness plate 1 is 1 cm to 2.5 cm. The length of each grid of the black-and-white grid test paper 2 in the length direction of the film thickness plate 1 can be adjusted according to actual testing requirements. The length of the black-and-white grid in the black-and-white grid test paper affects the amount of the paint to be tested sprayed during testing. By spraying the paint to be tested on the black-and-white grid test paper 2 multiple times, the thickness of the paint to be tested accumulated on the black-and-white grid increases after each spraying, and the degree of coverage of the black-and-white grid is enhanced. When the black-and-white grid of the black-and-white grid test paper 6 cannot be seen after spraying, the boundary between the area of the black-and-white grid covered by the paint to be tested and the area of the black-and-white grid not covered by the paint to be tested can be obtained. The above boundary is the reference line 6. By measuring the thickness of the paint to be tested on the reference line 6, the black-and-white hiding power of the paint to be tested can be determined, and the reference color value can be measured on the reference line 6 of the test plate 3.

[0041] In an exemplary embodiment, before the test plate 3, the film thickness plate 1, and the black-and-white grid test paper 2 are sprayed with the paint to be tested, step S210 is performed.

[0042] Step S210: Preparation procedure before the test plate 3 is sprayed with paint. The preparation procedure includes spraying the paint. The above preparation procedure should be the same as the preparation procedure in the paint spraying process of the actual spraying scene.

[0043] It should be noted that, in Figure 3 , the ordinate is the thickness of the film after the paint to be tested is sprayed, and the abscissa is the distance between the measuring point in the second direction within the spraying area and the spraying track 6. The second direction is perpendicular to the first direction, that is, Figure 3 The abscissa has positive and negative values, that is, the spraying track 6 is a boundary, the positive side of the spraying track 6 is positive, and the negative side of the spraying track 6 is negative. The film thickness at the spraying track 6 is the maximum peak film thickness point. The spraying track 6 in the above is a straight line formed by the peak film thickness point during spraying of the paint to be tested. It can be seen from Figure 3 that the closer to the peak film thickness point, the thicker the film thickness of the paint to be tested, and the farther from the peak film thickness point, the thinner the film thickness of the paint to be tested. Therefore, after the test plate 3 and the film thickness plate 1 are sprayed multiple times, the film thickness of the paint to be tested closer to the spraying track 6 is thicker, and the film thickness of the paint to be tested farther from the spraying track 6 is thinner in the second direction. Therefore, the film thickness of the paint to be tested at any two points of the test plate 3 and the film thickness plate 1 in the first direction is the same.

[0044] It should be noted that the test plate 3 is sprayed according to the color paint spraying process of the actual spraying situation, and the color value on the test plate 3 is more consistent with the spraying effect of the actual spraying area of the vehicle, so the test plate 3 is used to measure the color value; since the film thickness plate 1 is only sprayed with the color paint to be measured, the film thickness of the color paint to be measured can be accurately measured on the film thickness plate 1. By measuring the color difference value on the test plate 3 and measuring the film thickness at the corresponding position of the film thickness plate 1, the engineering hiding power film thickness corresponding to the actual spraying situation of the color paint to be measured can be obtained to determine the engineering hiding power. The actual spraying situation includes spraying methods such as air spraying or electrostatic spraying, and the measurement results obtained by different spraying methods are different. In an exemplary embodiment, the test plate 3 and the film thickness plate 1 are automatically sprayed by a spin cup or a spray gun, wherein when the spin cup is used for spraying, the spray mist width can be adjusted by adjusting the shaping air volume. When measuring the engineering hiding power film thickness, the size of the spray mist of the color paint to be measured will affect the accuracy of the measurement. Please refer to Figure 3 , the ordinate is the thickness of the film thickness after the color paint to be measured is sprayed, the abscissa is the distance between the measuring point in the second direction within the spraying area and the spraying track 6, the second direction is perpendicular to the first direction, the solid line shows the film thickness change of narrow mist spraying, and the dotted line shows the film thickness change of wide mist spraying. As can be seen from Figure 3 , when narrow mist spraying is performed, the film thickness change rate of the spraying area along the second direction is larger; as can be seen from Figure 3 , when wide mist spraying is performed, the film thickness change rate of the spraying area along the second direction is smaller. Therefore, when the method for determining the hiding power of the color paint is used, the resolution is higher, and the obtained film thickness value is more accurate, but when spraying is performed, the length of the test plate 3 and the film thickness plate 1 required in the second direction is longer when wide mist is used than when narrow mist is used, so when the size of the spraying mist is selected, the accuracy of the measurement and the cost of the measurement should be considered.

[0045] As described above, it can be understood that since the spraying track 6 extends along the first direction, the dividing line between the area covered by the black and white test paper and the area not covered by the color paint to be measured should also extend along the first direction.

[0046] In an exemplary embodiment, the moment when the black and white squares of the black and white test paper 2 located on the spraying track 6 are covered is determined by visual observation or a device, and the spraying is stopped, and the area of the black and white squares covered by the color paint to be tested and the area of the black and white squares not covered by the color paint to be tested are determined by visual observation or a device to determine the reference line 5, and the film thickness of the color paint to be tested on the reference line 5 of the film thickness plate 1 is the black and white hiding power film thickness. It should be noted that the reference line 5 is a man-made dividing line, and the reference line 5 is affected by the subjectivity of the observer and the resolution of the device, and the definition of the reference line 5 is that the black and white squares near one side of the reference line 5 are covered by the color paint to be tested, and the black and white squares near the other side of the reference line 5 are not covered by the color paint to be tested, that is, the black and white squares on the reference line 5 are just covered by the color paint to be tested, and the reference line 5 indicates the thinnest film thickness that the color paint to be tested can cover the black and white squares.

[0047] In an exemplary embodiment, the film thickness plate 1 and the test plate 3 are rectangular, the length direction of the film thickness plate 1 and the test plate 3 extends along the second direction, and the film thickness plate 1 and the test plate 3 are arranged side by side along the first direction, and the spraying track 6 coincides with the center line of the film thickness plate 1, and the center line extends along the first direction. The above spraying mode can make the film thickness of the color paint to be tested on both sides of the spraying track 6 of the film thickness plate 1 and the test plate 3 present a trend of becoming thinner in the second direction, so that a group of black and white hiding power film thickness and engineering hiding power film thickness can be obtained on both sides of the spraying track 6 after one spraying, thereby increasing the confidence of the determination.

[0048] Step S130: The color value corresponding to the reference line 5 of the test plate 3 is the reference color value, the reference line 5 is the dividing line between the area covered by the color paint to be tested and the area not covered by the color paint to be tested on the black and white test paper 6, the film thickness plate 1 and the test plate 3 both have a test area, the test area is located on the side of the reference line 5 away from the spraying track 6, a plurality of color value measurement points are taken in the test area of the test plate 3 along the second direction perpendicular to the first direction, and the color difference value between each color value measurement point and the reference color value is measured respectively, and based on the color difference value and the preset color difference value, the engineering hiding power line 4 extending along the first direction is determined to obtain the engineering hiding power film thickness.

[0049] In an exemplary embodiment, after the spraying is stopped, before a plurality of color value measurement points are taken in the test area 7 of the test plate 3 along the second direction, step S310 is included.

[0050] Step S310: The finishing process of the test plate 3 after the paint spraying, the finishing process includes varnish spraying and drying; the film thickness plate 1 and the black and white test paper 2 are dried. The above preparation process should be the same as the finishing process in the paint spraying process of the actual spraying scene.

[0051] It should be noted that the black-and-white grid hiding power film thickness is used to represent the hiding ability of the color paint to be tested on the black-and-white grid, that is, the thinner the black-and-white grid hiding power film thickness, the better the black-and-white grid hiding power; the engineering hiding power film thickness is used to represent the hiding ability of the color paint to be tested corresponding to the actual spraying situation, that is, the thinner the engineering hiding power film thickness, the better the engineering hiding power.

[0052] In an exemplary embodiment, based on the color difference value and the preset color difference value, the engineering hiding power line 4 extending along the first direction is determined to obtain the engineering hiding power film thickness, including steps S410, S420 and S430:

[0053] Step S410: When the color difference value between the color value measurement point and the reference color value is greater than the preset color difference value, the color value measurement point is taken on the test plate 3 along the second direction towards the reference line 5.

[0054] Step S420: When the color difference value between the color value measurement point and the reference color value is less than the preset color difference value, the color value measurement point is taken on the test plate 3 along the second direction away from the reference line 5.

[0055] Step S430: When the color difference value between the color value measurement point and the reference color value is equal to the preset color difference value, the straight line of the film thickness plate 1 and the test plate 3 passing through the color value measurement point in the first direction is the engineering hiding power line 4, and the film thickness of the color paint to be tested on the engineering hiding power line 4 of the film thickness plate 1 is the engineering hiding power film thickness.

[0056] In an exemplary embodiment, the color difference value is measured by a color difference meter, and the film thickness of the color paint to be tested on the film thickness plate 1 is measured by an electromagnetic film thickness measuring instrument. The types of the color difference meter and the film thickness measuring instrument can be adjusted according to the needs of use.

[0057] It should be noted that the preset color difference value is a general value, which is generally set to 1.4 or 1.7.

[0058] In summary, by spraying the film thickness plate 1 and the test plate 3 along the first direction, the color paint to be tested on the film thickness plate 1 and the test plate 3 has a film thickness with uniform thickness change in the second direction, and more accurate film thickness data can be obtained when determining the engineering hiding power of the color paint. At the same time, compared with the traditional method, the method for determining the hiding power of the color paint is simpler and more efficient, and has good industrial promotion value.

[0059] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for determining the hiding power of a paint, characterized in that, include: The test color paint is sprayed onto the test plate, the film thickness plate, and the black and white grid test paper along the first direction, wherein the test plate, the film thickness plate, and the black and white grid test paper are all located on the spraying trajectory of the test color paint; During a single spraying operation, the spraying is performed by moving unidirectionally along the spraying trajectory. After a single spraying operation is completed, the black and white grid test paper is observed. If the black and white grid test paper is located within the coverage area on the spraying trajectory and includes at least one complete black grid and one complete white grid, then the spraying is stopped; otherwise, the spraying continues. The color value on the test board corresponding to the baseline is the baseline color value. The baseline is the dividing line between the area covered by the paint to be tested and the area not covered by the paint to be tested on the black and white grid test paper. Both the film thickness plate and the test board have a test area. The test area is located on the side of the baseline away from the spraying trajectory. Multiple color value measurement points are taken in the test area of ​​the test board along a second direction perpendicular to the first direction, and the color difference value between each color value measurement point and the baseline color value is measured. Based on the color difference value and the preset color difference value, the engineering hiding force line extending along the first direction is determined to obtain the engineering hiding force film thickness. The thickness of the paint film to be measured on the reference line is the black and white hiding power film thickness.

2. The method for determining the hiding power of paint according to claim 1, characterized in that, Based on the color difference value and the preset color difference value, the engineering masking force line extending along the first direction is determined to obtain the engineering masking force film thickness, including: When the color difference between the color value measurement point and the reference color value is greater than the preset color difference value, the color value measurement point is taken on the test plate along the second direction toward the reference line; When the color difference between the color value measurement point and the reference color value is less than the preset color difference value, the color value measurement point is taken on the test plate away from the reference line along the second direction. When the color difference between the color value measurement point and the reference color value is equal to the preset color difference value, the straight line of the film thickness plate and the test plate passing through the color value measurement point in the first direction is the engineering hiding force line, and the film thickness of the paint to be tested on the film thickness plate on the engineering hiding force line is the engineering hiding force film thickness.

3. The method for determining the hiding power of paint according to claim 1, characterized in that: The film plate is provided with a strip of black and white grid test paper extending along a second direction. The length of the black and white grid test paper in the second direction is greater than or equal to the length of the film plate in the second direction, and the width of the black and white grid test paper in the first direction is less than the width of the film plate in the first direction.

4. The method for determining the hiding power of a paint according to claim 1, characterized in that, Before applying paint to the test panel, film thickness plate, and black and white checkered test paper, the following steps are included: The preparation process before spraying the test panel with colored paint includes spraying the intermediate coat paint.

5. The method for determining the hiding power of a paint according to claim 1, characterized in that, After spraying is stopped, before taking multiple color value measurement points along the second direction within the test panel, the process includes: The finishing process after the test panel is coated with colored paint includes clear varnish spraying and drying. Dry the film plate and the black and white grid test paper.

6. The method for determining the hiding power of a paint according to any one of claims 1-5, characterized in that: Both the test plate and the film thickness plate are rectangular. The width direction of both the film thickness plate and the test plate extends along the first direction, and the length direction of both the film thickness plate and the test plate extends along the second direction.

7. The method for determining the hiding power of a paint according to claim 6, characterized in that: The spraying trajectory coincides with the centerline of the film thickness plate, and the centerline extends along the first direction.

8. The method for determining the hiding power of a paint according to any one of claims 1-5, characterized in that: The length of each grid of the black and white test paper in the length direction of the film thickness plate is 1cm to 2.5cm.

9. The method for determining the hiding power of a paint according to any one of claims 1-5, characterized in that: The test plate and the film thickness plate are automatically coated using a rotary cup or spray gun.

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