Method for measuring adhesion strength of coating film

Abstract

To provide a method for measuring adherence strength of a coat, capable of directly and accurately measuring adherence strength of a coat in which a fluid layer is formed under a top dryness layer.SOLUTION: When adherence strength of a coat in which a fluid layer is formed under a top dryness layer is measured, a measurement device 1 that sets a force in a vertical direction to be acted on a cutting blade 100 with weight of a weight and can measure a horizontal force acting on the cutting blade 100 is used. First, while using a first weight to apply a force in a vertical direction to the cutting blade 100, the cutting blade 100 is made to carry out biaxial motion until the tip end of the cutting blade 100 reaches the surface of a base material B. Then, a second weight having minimum weight capable of maintaining a contact state between the tip end of the cutting blade 100 and the surface of the base material B is used to horizontally move the cutting blade while applying a force in a vertical direction to the cutting blade 100. A horizontal force at this time is then measured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for measuring the adhesive strength of a coating film, and more particularly to a method for measuring the adhesive strength of a coating film in which a fluidized layer is formed below an upper dry layer. [Background technology]

[0002] There are various types of foundations used in makeup, including cake, cream, and liquid types, but all of them are made by adding coloring ingredients such as pigments to a base such as oil, and when applied, they have the effect of covering up blemishes, freckles, pores, etc., and smoothing the appearance of the skin surface.

[0003] When such a foundation is applied to the skin, the surface dries to form a film, forming an upper dry layer, and underneath this a fluid layer made of an oily base is formed. Whether the foundation, which forms the upper dry layer and fluid layer, adheres firmly to the skin (in other words, whether the foundation does not float) is extremely important for the performance of the foundation, but to date, no method has been proposed for directly measuring the adhesive strength of foundation, and adhesive strength has had to be estimated using numerical values ​​of factors that affect the adhesive strength of foundation, such as the viscoelasticity of the materials contained in the foundation and the blending ratio of the base (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-132527 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of these problems, and its object is to provide a method for measuring the adhesion strength of a coating film that can directly and accurately measure the adhesion strength of a coating film, such as a foundation, in which a fluid layer forms below an upper dry layer. [Means for solving the problem]

[0006] As a result of trial and error in order to achieve the above-mentioned objective, the inventors discovered that when measuring the horizontal force acting on the cutting blade, which indicates the adhesion strength of the coating film, it is possible to directly and accurately measure the adhesion strength of the coating film by measuring the horizontal force in two steps: a first step in which the cutting blade reaches the interface with the substrate, and a second step in which the cutting blade, having reached the interface, is moved horizontally along the interface, and this led to the completion of the present invention.

[0007] In order to achieve the above object, a method for measuring the adhesion strength of a coating film according to claim 1 of the present invention is a method for measuring the adhesion strength of a coating film in which a fluidized layer is formed below an upper dry layer, and comprises: a pre-step of forming the coating film on the surface of a substrate having a flat surface; and a measuring step of measuring the horizontal force while cutting the cutting blade into the coating film using a measuring device having a structure in which a cutting blade can move relatively along two axes in horizontal and vertical directions, capable of arbitrarily setting the vertical force to be applied to the cutting blade, and equipped with a horizontal force measuring means for measuring the horizontal force acting on the cutting blade. The measuring step comprises a first step of applying a vertical force to the cutting blade with a first load and causing the cutting blade to perform biaxial movement until the tip of the cutting blade reaches the surface of the substrate; and a second step of horizontally moving the cutting blade following the first step while applying a vertical force to the cutting blade with a second load of a minimum weight capable of maintaining contact between the tip of the cutting blade and the surface of the substrate. In the first step, the measurement result of the horizontal force measuring means transitions in the order of a first stage where the horizontal force increases as the cutting blade starts to cut, a second stage where the increase in the horizontal force stops and becomes substantially flat, and a third stage where the horizontal force that had been flat starts to increase again, and then the process is switched to the second step. It is characterized by:

[0008] The subject state measuring device according to the present invention employs the following configuration as a preferred embodiment thereof. (1) The switching to the second step is performed after a certain time has elapsed since the transition to the third stage. (2)The first load is applied by a weight that allows the cutting blade, which moves along at least two axes, to cut through the upper dry layer of the coating film and cut into the fluidized layer.

[0009] ( 3 ) The second load is applied by a weight of the minimum weight necessary to maintain contact between the tip of the cutting blade and the surface of the substrate.

[0011] (4) The measuring device is characterized by including a vertical displacement measuring means for measuring the vertical displacement of the cutting blade.

[0012] (5) The measuring step is carried out at different times after the previous step, thereby measuring the change over time of the upper dry layer of the coating film.

[0013] (6) The coating film is a foundation. [Effects of the Invention]

[0014] According to the present invention, in measuring the adhesion strength of a coating film in which a fluidized layer is formed below an upper dry layer, the method includes a first step in which a first weight is used to apply a vertical force to a cutting blade, causing the cutting blade to perform biaxial movement until the tip of the cutting blade reaches the interface between the coating film and the substrate, and a second step in which a second weight, heavy enough to maintain contact between the tip of the cutting blade and the surface of the substrate, is used to apply a vertical force to the cutting blade, causing the cutting blade to perform uniaxial movement horizontally. Therefore, the cutting blade that reaches the surface of the substrate in the first step moves horizontally in the second step without lifting off the surface (interface) of the substrate. Therefore, the horizontal force measured in the second step indicates the adhesion strength of the coating film to the substrate surface, allowing for direct measurement of the adhesion strength of the coating film.

[0015] In particular, in this second step, by using a second weight (critical normal load) that applies a vertical force to the cutting blade and that is of the minimum weight necessary to maintain contact between the tip of the cutting blade and the surface of the substrate, the effects of friction caused by contact between the cutting blade and the substrate can be minimized, allowing the adhesion strength of the coating film to be accurately measured. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a front view showing an example of a measuring device used to measure the adhesive strength of a coating film according to the present invention. [Figure 2] FIG. 1 is a perspective view showing an example of a state in which a foundation, which is a test object, is applied to a substrate. [Figure 3] 10 is a graph showing an example of the relationship between the cutting depth of the cutting blade and the horizontal force applied to the same test object. [Figure 4] 10 is a graph showing another example of the relationship between the cutting depth of the cutting blade and the horizontal force applied to the same test object. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same reference numerals denote the same components or elements throughout the drawings.

[0018] 1 shows a schematic configuration of a measuring device 1 used to measure the adhesive strength of a coating film according to the present invention. The measuring device 1 has a structure in which a cutting blade 100 can move relatively along two axes, in the horizontal and vertical directions, the vertical force acting on the cutting blade 100 is set by the weight of a weight 12, and the measuring device 1 is equipped with a horizontal force measuring means 4 for measuring the horizontal force acting on the cutting blade 100.

[0019] More specifically, this measuring device 1 is composed of, as its main parts, a base 2, a support section 3 provided on the base 2, a horizontal force measuring means 4 for measuring the horizontal load acting on the cutting blade 100, an arm section 5 supported so as to be swingable by the support section 3, a tool holding section 6 for detachably holding the cutting blade 100, a mounting table 7 for placing a weight 12 that applies a vertical load to the cutting blade 100, a chuck section 8 for holding the specimen W, a contact angle adjustment section 9 for adjusting the contact condition between the specimen W and the tip (cutting edge) of the cutting blade 100, a horizontal drive mechanism section 10 for moving the specimen W horizontally relative to the cutting blade 100, and a control section 11.

[0020] The base 2 is a base for the device having a horizontal surface, and the support unit 3, horizontal drive mechanism unit 10, etc. are mounted on this surface. In this embodiment, the base 2 is fixed onto the device support stand 13.

[0021] The support column 3 is a column-shaped member that is provided vertically on the surface of the base 2. A blade receiving portion 15 is provided at the upper end of the support column 3, which engages with a fulcrum blade 14 provided on the arm section 5 to support the arm section 5 so that the arm section 5 can swing, and this blade receiving portion 15 constitutes the swing fulcrum of the arm section 5. Specifically, a blade support groove 16 that engages with the cutting edge of the fulcrum blade 14 is formed in the upper end surface of the blade receiving portion 15, and the cutting edge of the fulcrum blade 14 is housed within this blade support groove 16.

[0022] The support column 3 is also provided with a lifting stage 17 that adjusts the height position of the blade receiving portion 15. The lifting stage 17 has a structure that allows the height position of the blade receiving portion 15 to be adjusted up and down (vertically), and by adjusting the height position of this lifting stage 17, the height position of the horizontal force measuring means 4, which will be described later, and further the height position of the tip of the cutting blade 100 can be adjusted.

[0023] The horizontal force measuring means 4 is composed of a measuring device (for example, a load cell) that converts the horizontal force (horizontal force) acting on the cutting blade 100 into an electrical signal, and is connected to the support section 3 so as to be movable up and down. In this embodiment, one end (the lower part on the back side) of the horizontal force measuring means 4 is connected to the support section 3 via a slider 18, and this slider 18 allows the measuring section 4 to move freely up and down (in the vertical direction). The horizontal force measuring means 4 is electrically connected to the control section 11, and the measurement results by the horizontal force measuring means 4 are input to the control section 11.

[0024] The arm portion 5 is a member that serves as a balance beam for suspending the horizontal force measuring means 4 in a balance mechanism that uses the blade receiving portion 15 (fulcrum blade 14) as a swing fulcrum, and is provided with an adjustment weight 19 for balance adjustment at one end and a hanging portion 20 for suspending the horizontal force measuring means 4 at the other end.

[0025] The arm 5 is equipped with an arm level adjustment mechanism 30 that adjusts the arm 5 to a horizontal position. The arm level adjustment mechanism 30 mainly comprises a micrometer 28 that moves a horizontal adjustment bar 29, which is positioned to maintain a horizontal state, in the vertical direction, and the arm level adjustment bar 29 that abuts against the arm 5 from above at equidistant positions (two positions in the illustrated example) on either side of the fulcrum blade 14. By operating the micrometer 28 to lightly press the arm level adjustment bar 29 against the arm 5, the arm 5 can be forced to be in a horizontal position. Note that zero point adjustment of the displacement sensor 25, which will be described later, i.e., adjustment of the vertical position of the displacement sensor 25, is performed with the arm 5 forcibly maintained in a horizontal position by the arm level adjustment mechanism 30.

[0026] The adjustment weight 19 is a weight for balancing the arm section 5 when the horizontal force measuring means 4 is suspended from the suspension section 20, and in this embodiment, the adjustment weight 19 is attached to one end of the arm section 5 so that it can slide left and right (horizontally) using the slide mechanism 50, and the arm section 5 is configured to be balanced by making it possible to change the distance from the fulcrum blade 14 to the adjustment weight 19.

[0027] The hanging part 20 is a part for detachably attaching the horizontal force measuring means 4 to the other end of the arm part 5, and in this embodiment, a chain of metal rings is used as this hanging part 20, one end of which is connected to the other end of the arm part 5 and the other end is connected to the upper end of the horizontal force measuring means 4, thereby forming a structure in which the horizontal force measuring means 4 is hung from the arm part 5.

[0028] Further, at approximately the center of the arm portion 5, a fulcrum blade 14 is provided which constitutes a swing fulcrum that allows the arm portion 5 to function as a balance beam, and the cutting edge of this fulcrum blade 14 is supported by the blade support groove 16 of the blade receiving portion 15.

[0029] The tool holding unit 6 is a clamp device for detachably holding the cutting blade 100, and as shown in Figure 1, is provided on the surface of the horizontal force measuring means 4 opposite to the surface facing the support unit 3 so as to hold the cutting blade 100 facing downward. Here, the horizontal force measuring means 4 on which the tool holding unit 6 is provided is, as described above, suspended from the suspension unit 20 of the arm unit 5 and connected to the support unit 3 so as to be movable up and down by the slider 18, so that the height position of the tool holding unit 6 can be adjusted by adjusting the vertical position of the horizontal force measuring means 4.

[0030] In this regard, the measuring device 1 of this embodiment is provided with vertical displacement measuring means 25 (for example, a measuring device capable of measuring displacement on the nano-order, such as a capacitance displacement meter or a laser displacement meter) that measures the vertical displacement (vertical displacement) of the cutting blade 100, and the measurement results of the vertical displacement measuring means are also input to the control unit 11. Reference numeral 26 denotes a displacement sensor position adjusting mechanism for adjusting the vertical position of the displacement sensor 25; in this embodiment, this displacement sensor position adjusting mechanism 26 is attached to the support part 3, and by adjusting the sensor position adjusting mechanism 26, the vertical position of the displacement sensor 25 can be adjusted.

[0031] The cutting blade 100 preferably has a cutting edge formed from a superhard material, such as a superhard alloy or superhard diamond. As will be described later, in this embodiment, horizontal force is measured using a foundation as the test object W, so a cutting blade 100 with a tip R of 500 nm to 7 μm is preferably used. In the measurement of horizontal force shown in FIGS. 3 and 4, which will be described later, a cutting blade made of CBN (Cubic Boron Nitride) with a tip R of approximately 5 μm was used.

[0032] The mounting table 7 is a space for placing a weight 12 that adjusts the vertical force applied to the cutting blade 100, and is provided above the tool holding part 6, so that the weight of the weight 12 placed on the mounting table 7 acts on the cutting blade 100 as a vertical load. Therefore, the vertical force applied to the cutting blade 100 can be freely (arbitrarily) set by adjusting the weight of the weight 12 placed on the mounting table 7.

[0033] The chuck unit 8 is a chuck device that detachably holds the inspected object W, and is disposed below the tool holder 6. Therefore, by adjusting the height position of the tool holder 6, the tip of the cutting blade 100 can be made to act on the inspected object W. Note that in this embodiment, a vacuum base that adsorbs and holds the inspected object W is used as the chuck unit 8, but a chuck mechanism other than a vacuum base (for example, a mechanical chuck device or an electrostatic chuck) may be used as long as it has a structure that can detachably hold the inspected object W.

[0034] The contact angle adjustment unit 9 is a mechanism for finely adjusting the angle of the chuck unit 8 in order to adjust the contact state between the specimen W held by the chuck unit 8 and the cutting edge of the cutting blade 100, and in this embodiment is composed of a goniostage disposed below the chuck unit 8. By providing this goniostage, the measuring device 1 shown in this embodiment can position the surface of the specimen W parallel to the cutting edge of the cutting blade 100 to bring the specimen W and cutting blade 100 into close contact with no gap between them, or can bring the specimen W into contact with the cutting blade 100 at a predetermined inclination.

[0035] In the measuring device 1 shown in this embodiment, when aligning the cutting blade with the specimen W using the contact angle adjustment unit 9, a backlight 24 is irradiated onto the cutting edge (tip of the cutting blade) from the back side of the cutting blade, and the gap light is observed with a camera 31 positioned in front, thereby enabling alignment of the cutting blade with the specimen W.

[0036] The horizontal drive mechanism 10 is a mechanism for moving the specimen W held by the chuck 8 in the horizontal direction relative to the cutting blade 100. In this embodiment, the horizontal drive mechanism 10 is mainly composed of a horizontal movement stage 21 that can move forward and backward toward the support 3, and a drive motor 22 that is drivingly connected to the horizontal movement stage 21 via a drive connection mechanism 23 such as a ball screw. In the measurement of the horizontal force shown in FIGS. 3 and 4 (described later), the horizontal force was measured while the horizontal movement stage 21 was moved horizontally at a speed of 0.5 μm / s. Incidentally, if this horizontal movement speed is slowed to about 0.01 μm / s, the horizontal force can be measured without cutting into the substrate B, even if a diamond blade, which is sharper than CBN, is used as the cutting blade 100.

[0037] Specifically, the horizontally moving stage 21 is placed on the surface of the base 2, and the contact angle adjustment unit 9 and the chuck unit 8 are placed on this horizontally moving stage 21. The drive motor 22 is formed, for example, by a stepping motor, and is electrically connected to the control unit 11, which will be described later, so that the horizontally moving stage 21 can move forward and backward toward the support unit 3 under the control of the control unit 11.

[0038] The control unit 11 is a device that controls the drive motor 22 and processes data of the measurement results of the horizontal force measurement means 4 and the vertical displacement measurement means, and is configured, for example, by a personal computer. Therefore, this personal computer is equipped with at least software for controlling the drive motor 22 and software for processing data of the measurement results.

[0039] In the measuring device 1 configured in this manner, a weight 12 having a weight corresponding to the vertical force to be applied to the cutting blade 100 is placed on the mounting table 7, and the horizontal drive mechanism 10 is driven to move the test piece W horizontally, thereby starting the cutting blade 100 to cut into the test piece W. Then, the horizontal force (horizontal force) applied to the cutting blade 100 during the cutting is measured by the horizontal force measuring means 4, while the depth of the cutting by the cutting blade 100 is measured by the vertical displacement measuring means.

[0040] Next, the measurement of the adhesive strength of foundation using the measuring device 1 will be described. When foundation is applied to the skin, the surface dries to form a film, forming an upper dry layer, and underneath this is formed a fluid layer composed of a base such as oil.

[0041] The applicant initially measured the adhesion strength of a coating film consisting of an upper dry layer and a fluid layer to a typical coating film, that is, measured the horizontal force acting on the cutting blade 100 while making a cut with the cutting blade 100, and found that the horizontal force acting on the cutting blade 100 transitions in the following order: a first stage in which the horizontal force increases as the cutting blade 100 begins to cut; a second stage in which the increase in the horizontal force stops and the horizontal force remains almost flat; and a third stage in which the horizontal force that had been flat begins to increase again.

[0042] Therefore, we examined this transition in horizontal force in detail, taking into account factors such as the cutting depth of the cutting blade 100, and found that the first stage corresponds to the stage when the cutting blade 100 is in the middle of cutting into the upper dry layer, the second stage corresponds to the stage when the tip of the cutting blade 100 has passed through the upper dry layer and reached the fluidized layer, and the third stage corresponds to the stage when the tip of the cutting blade 100 has reached the surface of the substrate B and friction is occurring between it and the substrate surface.

[0043] The horizontal force acting on the cutting blade 100 in this third stage is a combined value of the adhesive force of the coating film and the frictional force with the substrate B. Therefore, the applicant thought that the adhesive strength of the foundation to the substrate B could be measured by reducing the vertical load (vertical force) acting on the cutting blade 100 to a minimum weight (critical vertical load) and minimizing the friction generated between the tip of the cutting blade 100 and the surface of the substrate B, and conducted the following experiment.

[0044] First, two types of liquid foundation were prepared as the foundation to be used as the test subject W. Each foundation was applied to an acrylic substrate B with a flat, planar surface, as shown in Figure 2. More specifically, in the experiment shown in Figure 3, one of the foundations was applied to substrate B with a thickness of 6 μm, and in the experiment shown in Figure 4, the other foundation was applied to substrate B with a thickness of 4 μm. For each experiment, the horizontal force was measured multiple times (two times each, (a) and (b)).

[0045] Here, when cutting foundation with cutting blade 100 to measure horizontal force, the tip (cutting edge) of cutting blade 100 must be parallel to the surface of the foundation. However, because the surface of the foundation is uneven, the cutting edge of cutting blade 100 cannot be aligned with the surface of the foundation. Therefore, in this embodiment, prior to cutting, the cutting edge is aligned on a portion of acrylic substrate B where no foundation is applied, and then the subject W is moved horizontally to position cutting blade 100 on the foundation, bringing cutting blade 100 close enough to touch the surface, and then cutting is performed. By aligning the cutting edge on the flat surface of substrate B in this way, cutting can be performed with the cutting edge and substrate B parallel, resulting in clean scraping of the foundation.

[0046] A: Experimental example in Figure 3: First, a 7 g weight 12 is placed on the mounting table 7 as the first weight (load) (a vertical force of 7 g is applied to the cutting blade 100), and in this state, the cutting blade 100 is made to perform biaxial movement until the tip of the cutting blade 100 passes through the fluidized layer of the foundation and reaches the surface of the substrate B (hereinafter, this may be referred to as the "first step").

[0047] Here, the weight of the first weight is selected to be at least such that the cutting blade 100, which moves in two axes, can cut the upper dry layer of the foundation and cut into the fluid layer (in other words, such a weight that can transition from the first stage to the third stage described above by continuing the biaxial movement of the cutting blade 100).

[0048] Specifically, the weight of the first weight is selected depending on the ingredients of the foundation that will be the subject W, the size of the pigments contained in the foundation, and so on. If this weight is too light, the cutting blade 100 will not reach the surface of the substrate B, and as a result, the foundation will remain on the surface of the substrate B, and an increase in horizontal force due to friction between the substrate B and the cutting blade 100 (third stage) will not occur. Conversely, if it is too heavy, the cutting blade 100 will cut into the substrate B. Therefore, it is necessary to select an appropriate weight depending on the type of subject W so that the first weight is not too light or too heavy.

[0049] When performing the first step, if an upper dry layer has not been formed on the surface of the foundation, or if the upper dry layer has not dried sufficiently and is soft, the cutting blade 100 will reach the surface of the substrate B in the first step. Therefore, by monitoring the horizontal force acting on the cutting blade 100 or by monitoring the state of the cutting blade 100 with the camera 31, it is possible to easily check whether or not an upper dry layer has been formed.

[0050] In both of the two experiments shown in Figure 3, the horizontal force acting on the cutting blade 100 increased to approximately 25 to 30 mN in the first stage due to the first step, then in the second stage the horizontal force remained stable, and then in the third stage the horizontal force began to increase again due to friction between the cutting blade 100 and the surface of the substrate B.

[0051] Then, in the third step, the state in which the horizontal force is increasing is continued for a while, that is, the state in which the tip of the cutting blade 100 continues to scrape off the foundation while moving horizontally across the surface of the substrate B. At this time, the horizontal force acting on the cutting blade 100 is a numerical value that combines the frictional force and the adhesive force, so in the next step, in order to eliminate the frictional force, the relative horizontal movement of the cutting blade 100 is temporarily stopped, and while it is stopped, the weight placed on the mounting table 7 is replaced from the first weight to a second weight (load) of 1 g, the weight 12, and the cutting blade 100 is moved horizontally again, and the horizontal force acting on the cutting blade 100 at this time is measured (hereinafter, this may be referred to as the "second step").

[0052] Here, whether or not the cutting by the cutting blade 100 has transitioned to the third stage (and further, the timing to switch from the first step to the second step) can be detected by observing the change in the horizontal force acting on the cutting blade 100 or the vertical displacement of the cutting blade 100 (that is, it can be determined that the cutting blade 100 has transitioned to the third stage when the horizontal force acting on the cutting blade 100 changes from a plateau to an increase). In addition, the reason why this third stage is continued for a while is to ensure that the tip of the cutting blade 100 passes through the fluidized layer of the foundation and reaches the surface of the substrate B reliably, thereby bringing the tip of the cutting blade 100 (cutting edge) into close contact with the surface of the substrate B.

[0053] The weight of the second weight used in this second step is selected to be the minimum weight that can maintain contact between the tip of the cutting blade 100, which is in close contact with the interface by the first weight, and the surface of the substrate B, that is, the lightest possible weight within the range that does not cause the cutting blade 100 to float up even when the cutting blade 100 is moved horizontally.

[0054] The weight of this second weight is set appropriately depending on the contents of the subject W, such as the ingredients of the foundation and the type of pigment contained therein. That is, this second weight needs to be as light as possible (low load) to minimize the influence of friction between the cutting blade 100 and the substrate B, but if it is too light, the cutting blade 100 will float up during horizontal movement, while if it is too heavy, the influence of frictional force will be large or it will cut into the substrate B, so the weight of this second weight also needs to be selected appropriately.

[0055] In this way, by adjusting the weight of the weight 12, almost no friction (frictional resistance) occurs between the tip of the cutting blade 100 and the surface of the substrate B, and the horizontal force acting on the cutting blade 100 at this time is the horizontal force associated with the adhesion of foundation with the friction between the cutting blade 100 and the substrate B minimized, i.e., the adhesive strength of the foundation. This can be seen from the fact that almost the same measurement results (about 20 mN in the illustrated example) were obtained in the two experiments shown in Figure 3.

[0056] Furthermore, whether the measurement of the horizontal force in this second step was performed correctly, in other words, whether the cutting blade 100 scraped off the foundation correctly (the foundation did not remain on the surface of the base material B and did not cut into the base material B) can be confirmed by using a microscope or the like to check the surface of the base material B after the second step, so that the horizontal force acting on the cutting blade 100 can be accurately measured.

[0057] B: Experiment in Figure 4: In the experiment shown in Fig. 4, a 5 g weight 12 was first placed on the mounting table 7 as the first weight, and in this state, the cutting blade 100 was made to perform biaxial movement until the tip of the cutting blade 100 reached the surface of the substrate B (first step). Note that the weight of the first weight at this time was set to a weight that would allow the biaxially moving cutting blade 100 to cut through the upper dry layer of the foundation and cut into the fluidized layer, as in the experiment shown in Fig. 3, and a 5 g weight 12 was used in this experiment.

[0058] In this experiment, the horizontal force acting on the cutting blade 100 increased to approximately 10 to 15 mN in the first stage due to this first step, and then the horizontal force remained stable in the second stage, and then began to increase again in the third stage.

[0059] 4, as in the above, the state in which the horizontal force was increasing was continued for a while as the third stage, and then the weight placed on the mounting table 7 was changed from the first weight to a second weight (a weight of the minimum weight that could maintain contact between the tip of the cutting blade 100 and the surface of the substrate B), the cutting blade 100 was moved horizontally, and the horizontal force acting on the cutting blade 100 at this time was measured (second step). In the experiment of FIG. 4, since the specimen W was different from that in the experiment of FIG. 3, a 1.5 g weight 12 was used as the second weight.

[0060] In the experiment shown in Figure 4, the measurement results for the second step were almost the same throughout the two experiments (approximately 10 to 15 mN in the example shown), as shown in Figure 4(a) and (b), and in this case too, the adhesive strength of the foundation could be measured.

[0061] Thus, according to the present invention, when measuring the adhesion strength of a coating film in which a fluidized layer is formed below an upper dry layer, the method includes a first step in which a vertical force is applied to the cutting blade 100 using a first weight, causing the cutting blade 100 to perform biaxial movement until the tip of the cutting blade 100 reaches the surface of the substrate B, and a second step in which a vertical force is applied to the cutting blade 100 using a second weight of a weight sufficient to maintain contact between the tip of the cutting blade 100 and the surface of the substrate B, causing the cutting blade 100 to perform uniaxial movement by moving horizontally.Therefore, after the cutting blade 100 reaches the surface of the substrate B in the first step, it moves horizontally in the second step without lifting off the surface (interface) of the substrate B.Therefore, the horizontal force measured in this second step can be regarded as the adhesion strength of the coating film to the substrate B, making it possible to directly measure the adhesion strength of the coating film.

[0062] In particular, in this second step, by using a weight of the minimum weight necessary to maintain contact between the tip of the cutting blade 100 and the surface of the substrate B as the second weight that applies a vertical force to the cutting blade 100, the effect of friction occurring between the cutting blade 100 and the substrate B can be minimized, and the adhesion strength of the coating film can be accurately measured.

[0063] The above-described embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to these, and various design modifications are possible within the scope of the present invention.

[0064] For example, in the above-described embodiment, the case where the test piece W is moved horizontally when the cutting blade 100 cuts into the test piece W has been shown, but the cutting blade 100 may have a structure that allows for relative biaxial movement in the horizontal and vertical directions, and for example, a structure that moves the cutting blade 100 horizontally may be adopted. Furthermore, the detailed structure of the measuring device 1 used in the method for measuring the adhesion strength of a coating film according to the present invention can be modified as appropriate as long as the measuring device 1 has a structure that allows for relative biaxial movement of the cutting blade 100 in the horizontal and vertical directions, the vertical force acting on the cutting blade 100 is set by the weight of a weight, and the measuring device 1 is equipped with horizontal force measuring means 4 that measures the horizontal force acting on the cutting blade 100.

[0065] Furthermore, in the above-described embodiment, the measuring device 1 is provided with a vertical displacement measuring means for measuring the cutting depth of the cutting blade 100, but the vertical displacement measuring means may be omitted. When the measuring device 1 is provided with a vertical displacement measuring means as in this embodiment, it becomes possible to determine, for example, whether the cutting depth of the cutting blade 100 has transitioned to the third stage using the measurement results of this vertical displacement measuring means.

[0066] Furthermore, in the above-described embodiment, a foundation was used as the test subject W, but the method for measuring the adhesion strength of a coating film according to the present invention can also be applied to measuring the adhesion strength of coating films other than foundation (for example, paint, glue, adhesive, etc.) as long as the coating film forms a fluid layer below the upper dry layer.

[0067] In addition, the method for measuring the adhesion strength of a coating film according to the present invention can measure the change in the adhesion strength of the coating film over time, for example, by performing the first and second steps multiple times while changing the elapsed time after the coating film to be tested W is formed on the substrate B.

[0068] In the above-described embodiment, the weight 12 is replaced from the first weight to the second weight in the second step of the measurement process. However, when changing the weight from the first weight to the second weight, the weight of the weight 12 placed on the mounting table 7 can be gradually reduced. For example, when changing the weight of the weight 12 from 7 g (the first weight) to 1 g (the second weight), the weight can be gradually reduced, such as 7 g, 5 g, 3 g, 2 g, and 1 g. When gradually reducing the weight of the weight 12 in this manner, the horizontal movement stage 21 is moved slightly after the load is reduced until the horizontal force maintains approximately the same value. If the horizontal force value remains the same, the load is changed to the next lower load. This process is then repeated until the weight is reduced to the minimum weight (critical vertical load) that maintains contact between the tip of the cutting blade 100 and the surface of the substrate B, thereby changing the weight from the first weight to the second weight.

[0069] Furthermore, in the above-described embodiment, the vertical load acting on the cutting blade 100 is applied by the weight of the weight 12, but the vertical load may be set by a method other than the weight 12 (for example, by using a piezoelectric element or the like to enable the setting of the vertical load to be changed). If the vertical load is configured to be freely changeable by a piezoelectric element or the like, the vertical load can be changed without temporarily stopping the horizontal movement as is the case when setting the vertical load using the weight 12, and the adhesion strength of the coating film can be measured without considering static friction that occurs when the horizontal movement is resumed. [Explanation of symbols]

[0070] 1. State measuring device 2. Bass 3 Support section 4 Horizontal force measurement means 5 Arm section 6 Tool holding part 7 Mounting table 8 Chuck 9 Contact angle adjustment part 10 Horizontal drive mechanism 11 Control section 12 weight 14 Fulcrum Blade 15 Blade receiving part 17 Elevating Stage 18 Slider 19 Adjustment weight 20 Hanging part 21 Horizontal moving stage 22 Drive motor 100 cutting blade B Base material W Subject

Claims

1. A method for measuring the adhesion strength of a coating film in which a fluidized layer is formed under an upper dry layer, comprising: a pre-process of forming the coating film on a surface of a substrate having a flat surface; a measuring step of measuring the horizontal force acting on the cutting blade while cutting the coating film, using a measuring device having a structure in which the cutting blade can move relatively in two axes in the horizontal and vertical directions, capable of arbitrarily setting the vertical force acting on the cutting blade, and equipped with a horizontal force measuring means for measuring the horizontal force acting on the cutting blade; The measuring step a first step of biaxially moving the cutting blade while applying a vertical force to the cutting blade with a first load until the tip of the cutting blade reaches the surface of the base material; Following the first step, there is a second step of horizontally moving the cutting blade while applying a vertical force to the cutting blade with a second load of a minimum weight capable of maintaining contact between the tip of the cutting blade and the surface of the base material, In the first step, the measurement result of the horizontal force measuring means transitions in the order of a first stage where the horizontal force increases as the cutting blade starts to cut, a second stage where the increase in the horizontal force stops and becomes substantially flat, and a third stage where the horizontal force that had been flat starts to increase again, and then the process is switched to the second step. A method for measuring the adhesion strength of a coating film.

2. A method for measuring the adhesion strength of a coating film as described in Claim 1, characterized in that the switch to the second process is performed after the state in which the horizontal force has been increasing has continued for a while after the transition to the third stage.

3. 3. A method for measuring the adhesion strength of a coating film according to claim 1 or 2, characterized in that the first load is applied by a weight that allows the cutting blade, which moves in two axes, to cut through the upper dry layer of the coating film and cut into the fluidized layer.

4. 4. The method for measuring the adhesion strength of a coating film according to claim 1, wherein the second load is applied by a weight of the minimum weight necessary to maintain contact between the tip of the cutting blade and the surface of the substrate.

5. 5. The method for measuring the adhesive strength of a coating film according to claim 1, wherein the measuring device is provided with a vertical displacement measuring means for measuring the vertical displacement of the cutting blade.

6. A method for measuring the adhesion strength of a coating film described in any one of claims 1 to 5, characterized in that the measurement step is carried out at different times after the previous step, thereby measuring the change over time of the upper dry layer of the coating film.

7. 7. The method for measuring the adhesive strength of a coating film according to claim 1, wherein the coating film is a foundation.

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