Film thickness measurement method

Abstract

To provide a film thickness measurement method which can be used to measure the thickness of a film formed in a base composed of nonmetal, and which can suppress the impairing of aesthetic appearance of the base.SOLUTION: A film thickness measurement method according to one embodiment measures the thickness of a film M formed on surface B1 of a base B composed of nonmetal. The film thickness measurement method comprises: a step in which a transparent electrically conductive film 2 is pasted to the surface B1 of the base B; a step in which a film M is formed on the surface B1 of the base B and a surface 2b of the electrically conductive film 2 which is on the side opposite the surface B1; a step in which a probe 3d of an eddy current type film thickness meter 3 is brought into contact with the electrically conductive film 2 and calibration of the eddy current type film thickness meter 3 is performed; and a step in which the probe 3b of the calibrated eddy current type film thickness meter 3 is brought into contact with a surface M1 of the film M formed on the side opposite the electrically conductive film 2 to thereby measure the thickness of the M film formed on the surface B1.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a coating thickness measurement method for measuring the thickness of a coating film formed on a surface of a substrate. [Background technology]

[0002] Patent Document 1 describes a coating film formation method for forming a coating film layer on a nonmetallic substrate. In the coating film formation method, a metal sheet is laid on the substrate of a nonmetallic material such as a concrete wall. The metal sheet is a metal mesh with mesh openings ranging from several hundred μm to several mm, a metal foil, or a nonwoven fabric made of a metal foil.

[0003] The metal sheet is laid and fixed on the wall surface, which will be the base surface, with concrete nails. A coating layer is formed on top of this metal sheet. Therefore, even if the base surface is made of a non-metallic material, the metal sheet exerts an electrical correlation corresponding to the strength of the magnetic force or magnetic field through the coating layer. By utilizing this electrical correlation, it is possible to directly measure the thickness of the coating layer at any position using an electromagnetic or eddy current coating thickness gauge. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-279267 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned coating method, a metal sheet is laid and fixed on the base surface with concrete nails, and a coating layer is formed on the metal sheet, so that the thickness of the coating layer can be measured even if the base surface is made of a non-metallic material.

[0006] A transparent coating film may be used. When a colored metal sheet is placed on a base surface and a transparent coating film layer is formed on the metal sheet, the metal sheet is visible after the coating film layer is formed, which may cause a problem that the aesthetics of the base are marred. For example, when a transparent coating film layer is formed on a metal sheet placed on the surface of a base made of wood, the aesthetics of the wood grain may be marred.

[0007] An object of the present disclosure is to provide a coating thickness measurement method that can measure the thickness of a coating film formed on a non-metallic substrate while preventing damage to the aesthetic appearance of the substrate. [Means for solving the problem]

[0008] (1) The coating thickness measurement method according to the present disclosure is a coating thickness measurement method for measuring the thickness of a coating formed on the surface of a non-metallic substrate. The coating thickness measurement method includes the steps of attaching a transparent conductive film to the surface of the substrate, forming a coating on the surface of the substrate and on the surface of the conductive film opposite to the surface, calibrating the eddy current coating thickness gauge by contacting a probe of the eddy current coating thickness gauge with the conductive film, and measuring the thickness of the coating formed on the surface by contacting the calibrated probe of the eddy current coating thickness gauge with the surface of the coating opposite to the conductive film.

[0009] In this coating thickness measurement method, the thickness of a coating film formed on the surface of a non-metallic base is measured. A transparent conductive film is attached to the surface of the base, and a coating film is formed on the surface and on the surface of the conductive film opposite to the surface. The eddy current thickness gauge is calibrated by contacting the conductive film with a probe of the eddy current thickness gauge. Then, the thickness of the coating film formed on the surface of the base is measured by contacting the probe of the calibrated eddy current thickness gauge with the surface of the coating film opposite to the conductive film. Therefore, even if the base is made of a non-metal, the thickness of the coating film can be measured by the eddy current thickness gauge. In this coating thickness measurement method, a transparent conductive film is attached to the surface of the base, and the eddy current thickness gauge measures the thickness of the coating film with the probe in contact with the surface of the coating film opposite to the conductive film. Therefore, since the conductive film attached to the base is transparent, the conductive film cannot be seen even if a transparent coating film is formed on the base, so that the conductive film can be prevented from impairing the aesthetic appearance of the base.

[0010] (2) In the above (1), the surface resistivity of the conductive film may be less than 6 Ω / sq. In this case, by making the surface resistivity of the conductive film less than 6 Ω / sq, the range of film thicknesses that can be measured by an eddy current film thickness meter can be expanded.

[0011] (3) In the above (1) or (2), the base may be made of wood, and the coating film may be a fire-resistant paint. In this case, the coating film being a fire-resistant paint can provide fire resistance to the base. Furthermore, a transparent conductive film is attached to the surface of the base made of wood, and the thickness of the coating film is measured with the probe in contact with the surface of the coating film opposite to the conductive film. Therefore, since the conductive film attached to the base made of wood is transparent, the aesthetic appearance of the wood grain of the base can be prevented from being impaired even if a transparent coating film is formed. Effect of the Invention

[0012] According to the present disclosure, it is possible to measure the thickness of a coating film formed on a non-metallic substrate while preventing damage to the aesthetic appearance of the substrate. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view showing a coating thickness measurement device used in the coating thickness measurement method according to the embodiment; [Diagram 2] FIG. 1 is a diagram showing an example of a base material. [Diagram 3] FIG. 2 is a cross-sectional view showing a schematic view of a base material and a coating film. [Figure 4] 4 is a flowchart illustrating an example of steps of a coating thickness measurement method according to the embodiment. [Diagram 5] 5(a) and 5(b) are cross-sectional views showing a step of a coating thickness measuring method according to an embodiment. [Figure 6] FIG. 2 is a diagram showing one step of a coating thickness measurement method according to an embodiment. [Figure 7] 4 is a cross-sectional view showing one step of a coating thickness measuring method according to an embodiment. FIG. [Figure 8] 1 is a graph showing an example of the relationship between the surface resistivity of a conductive film and the measurable film thickness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the coating thickness measurement method according to the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding elements are given the same reference numerals, and duplicated explanations are omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

[0015] Fig. 1 is a perspective view showing a coating thickness measuring device 1 used in the coating thickness measuring method according to the present embodiment. As shown in Fig. 1, the coating thickness measuring device 1 includes a transparent conductive film 2 and an eddy current coating thickness meter 3. The conductive film 2 is a film having electrical conductivity. The eddy current coating thickness meter 3 is an instrument that measures the thickness (film thickness) of a coating film, which will be described later.

[0016] In this embodiment, "transparent" refers to a property of transmitting light and being see-through. "Transparent" may be colorless transparent, colored transparent, or translucent. "Transparent" may be like frosted glass. As described above, the conductive film 2 is transparent. Therefore, when the conductive film 2 is viewed, the opposite side of the conductive film 2 can be seen through.

[0017] For example, the surface resistivity of the conductive film 2 is less than 6 Ω / sq. Surface resistivity indicates the electrical resistance of a sheet-like or film-like substance having a uniform thickness. For example, the surface resistivity of the conductive film 2 is 0 Ω / sq or more and less than 6 Ω / sq. The surface resistivity of the conductive film 2 may be 1 Ω / sq or less, 0.35 Ω / sq or less, or 0.25 Ω / sq or less. In this embodiment, it is desirable that the surface resistivity of the conductive film 2 is as small as possible. The smaller the surface resistivity of the conductive film 2, the wider the range of film thickness that can be measured by the eddy current film thickness meter 3.

[0018] For example, the conductive film 2 includes a film and a conductive layer (conductive film) formed on the film. The conductive film 2 is formed, for example, by depositing a conductive layer on the film by sputtering or the like. The conductive layer may also be formed by engraving a circuit on the film. A metal mesh wired on the surface of the film may be formed as the conductive layer. That is, the conductive layer may be formed on the film by a metal mesh method. In this case, it is possible to further reduce the surface resistivity of the conductive film 2.

[0019] The conductive film 2 includes at least one of a polymer, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyarylate (PAR), polyethersulfone (PES), polyimide (PI), polycarbonate (PC), etc., and glass. The conductive layer of the conductive film 2 includes at least one of indium tin oxide (ITO), silver alloy (Ag alloy), titanium oxide (TiO), tin oxide (SnO), zinc oxide (ZnO), aluminum, aluminum alloy, copper, and copper alloy.

[0020] The conductive film 2 is a film that is attached to the surface B1 (see FIG. 2) of the base B. For example, the conductive film 2 may have an adhesive layer and a release paper. In this case, the release paper is peeled off from the adhesive layer and the adhesive layer is attached to the surface B1, thereby allowing the conductive film 2 to be attached to the surface B1. The conductive film 2 has a certain thickness. The thickness of the conductive film 2 is not particularly limited, but from the viewpoint of reducing the step and further increasing the accuracy of the measurement, the thinner the thickness, the more desirable it is.

[0021] The eddy current thickness gauge 3 has, for example, a main body 3b, a cable 3c extending from the main body 3b, and a probe 3d located at the end of the cable 3c opposite the main body 3b. The eddy current thickness gauge 3 measures the thickness of an object to be measured by bringing the probe 3d into contact with the object to be measured.

[0022] The probe 3d has a columnar shape. For example, the probe 3d has a ferrite core. When the ferrite core of the probe 3d is brought close to the surface of the measurement object, a high-frequency alternating current generates a vortex current (eddy current) on the surface of the measurement object. Since the eddy current flows in a direction that cancels the magnetic field, the current from the probe 3d is resisted.

[0023] Since the magnitude of this resistance correlates with the characteristics of the object to be measured and the distance from the probe 3d (film thickness), the eddy current film thickness gauge 3 measures the thickness of the object to be measured by converting the magnitude of this resistance into film thickness. For example, when measuring a metal sheet (an aluminum sheet as an example) as the object to be measured, the maximum film thickness that the eddy current film thickness gauge 3 can measure is 5 mm. The higher the surface resistivity of the object to be measured, the smaller the maximum film thickness that the eddy current film thickness gauge 3 can measure. It is desirable for the eddy current film thickness gauge 3 to have a high current output and a large measurable film thickness.

[0024] FIG. 2 is a plan view showing the base B as an example on which a coating film is formed. FIG. 3 is a schematic cross-sectional view showing the base B and the coating film M formed on the base B. For example, the base B is made of wood. In this case, the base B is wood having a grain B2 on the surface B1 of the base B. As an example, the base B is made of cedar wood. In this way, the base B is made of a non-metal. The coating film M has at least one of the functions of protecting the base B, maintaining the aesthetic appearance of the base B, and imparting special performance to the base B. In order to properly express the function of the coating film M, it is important to properly set the thickness (film thickness) of the coating film M. In order to manage the film thickness, it is required to be able to accurately measure the film thickness.

[0025] For example, the coating film M is a fire-resistant paint. A fire-resistant paint is a paint that imparts fire resistance to a substrate by foaming with heat and forming a carbonized layer. When the coating film M is a fire-resistant paint, the thickness of the coating film M greatly affects the fire resistance. Therefore, it may become necessary to accurately measure and manage the thickness of the coating film M when carrying out painting work. For example, the coating film M is a fire-resistant paint for wood.

[0026] The coating film M is transparent. Like the conductive film 2 described above, the coating film M may be colorless and transparent, colored and transparent, or translucent. The coating film M is, for example, a transparent fire-resistant paint for wood. In this case, the coating film M is transparent so as to make the most of the appearance of the wood grain B2 of the wood constituting the base B, and has the function of maintaining the high aesthetic quality of the wood grain B2.

[0027] Next, steps of the coating thickness measurement method according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a flow chart showing an example of steps of the coating thickness measurement method according to this embodiment. In the coating thickness measurement method, the thickness of the coating film M formed on the surface B1 of the base B is measured. Below, an example will be described in which the base B is wood, the coating film M is a transparent fire-resistant paint for wood, and the thickness of the coating film M applied to the base B is controlled.

[0028] The thickness of the coating film M, which is a fire-resistant paint, is generally 0.3 mm or more, and for example, on a vertical surface, a single application can only form a coating film M of about 0.05 mm. In this case, since it is necessary to apply the fire-resistant paint to the base B multiple times, it is important to accurately measure the thickness of the coating film M.

[0029] 5(a), a transparent conductive film 2 is attached to a surface B1 of a base B (attaching process, step S1). At this time, the conductive film 2 is attached to a part of the surface B1 of the base B. The conductive film 2 does not need to be attached to the entire surface B1, and it is sufficient to attach the conductive film 2 to only a part of the surface B1.

[0030] More specifically, a conductive film 2 having an area larger than the area of ​​the contact portion of the probe 3d with respect to the conductive film 2 is prepared, and this conductive film 2 is attached to the surface B1. For example, the conductive film 2 has a rectangular shape (square shape). As an example, the area of ​​the conductive film 2 attached to the surface B1 is 9 cm 2 (3cm x 3cm).

[0031] The conductive film 2 is attached to the surface B1 by, for example, an adhesive. However, the means for attaching the conductive film 2 to the surface B1 is not limited to an adhesive. As described above, when the conductive film 2 has an adhesive layer and a release paper, the release paper may be peeled off and the adhesive layer may be attached to the surface B1, thereby attaching the conductive film 2 to the surface B1.

[0032] Next, a coating film M is formed on surface B1 of the base B and on surface 2b of the conductive film 2 opposite surface B1 (a process for forming a coating film, step S2). For example, a fire-resistant paint that will become the coating film M is applied to surface B1 and surface 2b. As an example, the fire-resistant paint is applied to surface B1 and surface 2b by roller coating. However, the fire-resistant paint may also be applied to surface B1 and surface 2b by spray coating, and the means for applying the fire-resistant paint is not particularly limited. The coating film M is formed when the fire-resistant paint dries.

[0033] 6, apart from steps S1 and S2, calibration of the eddy current thickness gauge 3 is performed (calibration process, step S3). At this time, the eddy current thickness gauge 3 is calibrated by bringing a probe 3d of the eddy current thickness gauge 3 into contact with the conductive film 2. More specifically, the probe 3d is brought into direct contact with the surface 2b of the conductive film 2 to set the measurement value by the eddy current thickness gauge 3 to 0, thereby performing calibration to set the measurement value of the eddy current thickness gauge 3 in the absence of the coating film M to 0.

[0034] After steps S2 and S3, the thickness of the coating film M formed on the surface B1 is measured (measurement step, step S4) as shown in Fig. 7. At this time, the thickness of the coating film M is measured by contacting the probe 3d of the eddy current thickness meter 3 that has been calibrated as described above with the surface M1 of the coating film M opposite to the conductive film 2.

[0035] For example, application of a fire-resistant paint to form a coating film M and measurement of the thickness of the coating film M by an eddy current film thickness meter 3 are repeated until the thickness of the coating film M reaches a predetermined thickness. At this time, a more accurate thickness of the coating film M can be obtained by adding the thickness of the conductive film 2 to the thickness of the coating film M measured by the eddy current film thickness meter 3. This makes it possible to reliably impart the desired fire resistance to the base B. In this way, after the measurement of the thickness of the coating film M is completed, a series of steps in the coating film thickness measurement method according to this embodiment is completed.

[0036] Next, the effects of the coating thickness measurement method according to this embodiment will be described. In the coating thickness measurement method according to this embodiment, the thickness of the coating film M formed on the surface B1 of the base B made of a nonmetal is measured. A transparent conductive film 2 is attached to the surface B1 of the base B, and the coating film M is formed on the surface B1 and the surface 2b of the conductive film 2 opposite to the surface B1. The eddy current thickness gauge 3 is calibrated by bringing the probe 3d of the eddy current thickness gauge 3 into contact with the conductive film 2. Then, the probe 3d of the calibrated eddy current thickness gauge 3 comes into contact with the surface M1 of the coating film M opposite to the conductive film 2, thereby measuring the thickness of the coating film M formed on the surface B1 of the base B. Therefore, even if the base B is made of a nonmetal, the thickness of the coating film M can be measured by the eddy current thickness gauge 3.

[0037] In this coating thickness measurement method, a transparent conductive film 2 is attached to the surface B1 of a base B, and an eddy current coating thickness meter 3 measures the thickness of the coating film M with a probe 3d in contact with a surface M1 of the coating film M opposite the conductive film 2. Therefore, because the conductive film 2 attached to the base B is transparent, even if a transparent coating film M is formed on the base B, the conductive film 2 cannot be seen, and therefore it is possible to prevent the conductive film 2 from impairing the aesthetic appearance of the base B.

[0038] In this embodiment, the surface resistivity of the conductive film 2 may be less than 6 Ω / sq. In this case, by making the surface resistivity of the conductive film 2 less than 6 Ω / sq, the range of film thicknesses that can be measured by the eddy current film thickness gauge 3 can be expanded. Furthermore, as described above, the surface resistivity of the conductive film 2 may be 0.2 Ω / sq or less. In this case, 80% of the range of film thicknesses that can be measured by the eddy current film thickness gauge 3 can be measured.

[0039] In this embodiment, the base B is made of wood, and the coating film M is a fire-resistant paint. In this case, since the coating film M is a fire-resistant paint, the base B can be made fire-resistant. Furthermore, a transparent conductive film 2 is attached to the surface B1 of the base B made of wood, and the thickness of the coating film M is measured with the probe 3d in contact with the surface M1 of the coating film M opposite to the conductive film 2. Therefore, since the conductive film 2 attached to the base B made of wood is transparent, it is possible to prevent the aesthetic appearance of the wood grain B2 of the base B from being impaired even if a transparent coating film M is formed.

[0040] In the following, examples of the coating thickness measurement method according to the present disclosure will be described. The present disclosure is not limited to the contents of the following examples. In the examples, as shown in FIG. 7, a base B, a conductive film 2, an eddy current type coating thickness meter 3, and a coating M were prepared, and an experiment was conducted to obtain the relationship between the surface resistivity of the conductive film 2 and the measurable coating thickness.

[0041] In this experiment, the base B was wood (cedar), a transparent plastic plate for calibrating the eddy current thickness gauge 3 was used as a substitute for the coating M, and the thickness of this plastic plate was adjusted to set the coating thickness. The SWT-NEO dual type coating thickness gauge manufactured by Sanko Electronics Laboratory Co., Ltd. was used as the eddy current thickness gauge 3, and the SNFe-5 probe dedicated to the SWT series was used as the probe 3d. In this case, the maximum measurable coating thickness when a metal sheet (aluminum sheet) was used was 5 mm.

[0042] The results of this experiment are shown in Table 1 below. [Table 1]

[0043] The comparative example in Table 1 shows a case where the eddy current film thickness gauge 3 measures an opaque aluminum sheet. The measurable film thickness of 5.0 mm in the comparative example shows the limit of the measurable range of the eddy current film thickness gauge 3. Example 1 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 0.15 Ω / sq, Example 2 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 0.25 Ω / sq, Example 3 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 0.35 Ω / sq, Example 4 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 1 Ω / sq, Example 5 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 6 Ω / sq, Example 6 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 250 Ω / sq, and Example 7 in Table 1 shows a case where the surface resistivity of the conductive film 2 is 5000 Ω / sq.

[0044] Fig. 8 is a graph showing the results of this experiment. As shown in Table 1 and Fig. 8, it was found that the smaller the surface resistivity of the conductive film 2, the greater the film thickness that the eddy current film thickness meter 3 could measure. Specifically, if the surface resistivity is less than 6 Ω / sq, the film thickness can be measured, and in Example 4, where the surface resistivity is 1 Ω / sq, the measurable film thickness was 1 mm. And, in Example 1, where the surface resistivity is 0.15 Ω / sq, it was found that the measurable film thickness increased to 4.3 mm.

[0045] The embodiment and examples of the coating thickness measurement method according to the present disclosure have been described above. However, the coating thickness measurement method according to the present disclosure is not limited to the above-mentioned embodiment or example, and may be further modified within the scope of the gist described in the claims. In other words, the content and order of the steps of the coating thickness measurement method can be appropriately changed within the scope of the above gist.

[0046] For example, in the above-mentioned embodiment, an example was described in which a coating film M, which is a fireproof paint, is formed on a base B, which is wood. However, the type of base B and the type of coating film M can be changed as appropriate. For example, the base B may be wood flooring, and the coating film M may be a transparent urethane paint. In this case, the thickness of the coating film M, which protects the wood and adjusts slippage, can be measured by applying a urethane coating on the wood flooring. As an example, maintenance is performed on gymnasium floors periodically by removing the urethane coating and repainting them, and the coating film thickness measurement method can measure the thickness of the coating film M formed by the urethane coating, making it possible to confirm the thickness of the coating film M after application.

[0047] As another example different from the above, the base B may be concrete, and the coating film M may be a transparent concrete protective paint. One of the causes of concrete deterioration is carbon dioxide absorption by concrete, which causes the concrete to become neutral. To inhibit this carbonation, a concrete protective paint that absorbs carbon dioxide may be applied to the concrete. The coating thickness measurement method is capable of measuring the film thickness of the concrete protective paint formed on the concrete, and thus contributes to reliably inhibiting the carbonation of the concrete by applying a concrete protective paint of an appropriate thickness to the concrete.

[0048] Another example is its application to a tile peeling and repairing method. In this case, the base B is an exterior wall tile, and the coating film M is a transparent coating layer. One of the methods for peeling and repairing tiles on exterior walls is to apply a special transparent coating to the tile surface to preserve the appearance of the base B, and then fasten the tile to the wall with anchor pins or the like. The coating film M is transparent and strong, and its purpose is to integrate the tiles, so it is necessary to properly manage the coating film thickness of the coating film M. The coating film thickness measurement method can also measure the coating film thickness of the coating film M applied to the tiles as described above.

[0049] As described above, the material of the base B is not limited to wood, but may be concrete or even plastic. In this way, the material of the base B may be any non-metallic material. Also, in the above-mentioned embodiment, the conductive film 2 that is attached by adhesive or the like has been described. However, the conductive film 2 may be formed by applying a transparent paint. In this way, the type and form of the conductive film 2 can be changed as appropriate. [Explanation of symbols]

[0050] 1...coating thickness measuring device, 2...conductive film, 2b...surface, 3...eddy current coating thickness gauge, 3b...main body, 3c...cable, 3d...probe, B...base, B1...surface, B2...wood grain, M...coating film, M1...surface.

Claims

1. A coating thickness measurement method for measuring the thickness of a coating film formed on a surface of a non-metallic substrate, comprising: A step of attaching a transparent conductive film to a surface of the base; forming the coating film on a surface of the base and on a surface of the conductive film opposite to the surface; a step of calibrating the eddy current thickness gauge by bringing a probe of the eddy current thickness gauge into contact with the conductive film; a step of measuring a thickness of the coating film formed on the surface by contacting the probe of the calibrated eddy current thickness meter with a surface of the coating film opposite to the conductive film; Equipped with Coating thickness measurement methods.

2. The surface resistivity of the conductive film is less than 6 Ω / sq. The coating thickness measuring method according to claim 1.

3. The substrate is made of wood, and the coating is a fire-resistant paint. The coating thickness measuring method according to claim 1 or 2.

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