Method for removing coating layer

Abstract

To provide a coating layer removal method capable of achieving both suppression of breakage of a base material layer and suppression of insufficient removal of a coating layer.SOLUTION: A coating layer removal method is a method for removing a coating layer from a resin structure 1 including a base material layer made of a resin and the coating layer provided on a surface of the base material layer. This method includes a measurement step of measuring a thickness of the coating layer by detecting a boundary portion between the base material layer and the coating layer, a determination step of determining a condition of high-pressure water jetted from a nozzle based on a relationship between the thickness of the coating layer and the condition of the high-pressure water and the thickness of the coating layer measured in the measurement step, and a removal step of removing the coating layer from the resin structure by jetting the high-pressure water from the nozzle based on the condition determined in the determination step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a coating layer removal method. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 7-80839 discloses a method of removing a deteriorated surface layer of polycarbonate using high-pressure water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-80839 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method for producing recycled polycarbonate sheets described in JP-A-7-80839, it is difficult to select the conditions for high-pressure water (water pressure, distance between the nozzle and the polycarbonate sheet, nozzle movement speed, etc.). For example, if the water pressure is low or the distance between the nozzle and the polycarbonate sheet is large, removal of the deteriorated surface layer is insufficient. Conversely, if the water pressure is high or the distance between the nozzle and the polycarbonate sheet is small, there is a risk that the polycarbonate sheet may be damaged.

[0005] An object of the present invention is to provide a coating layer removal method that can simultaneously suppress damage to a substrate layer and suppress insufficient removal of a coating layer. [Means for solving the problem]

[0006] A coating layer removal method according to one aspect of this disclosure is a method for removing a coating layer from a resin structure including a substrate layer made of resin and a coating layer provided on a surface of the substrate layer, and includes: a measuring step for measuring a thickness of the coating layer by detecting a boundary between the substrate layer and the coating layer; a determining step for determining the conditions for the high-pressure water sprayed from a nozzle based on a relationship between the thickness of the coating layer and the conditions for the high-pressure water sprayed from a nozzle and the thickness of the coating layer measured in the measuring step; and a removing step for removing the coating layer from the resin structure by spraying the high-pressure water from the nozzle based on the conditions determined in the determining step. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a coating layer removal method that can simultaneously suppress damage to the substrate layer and suppress insufficient removal of the coating layer. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically illustrating a coating layer removal method according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a resin structure. [Figure 3] FIG. 1 is a perspective view schematically illustrating a micro-slurry jet erosion method. [Figure 4] 1 is a graph schematically showing measurement results obtained by a micro-slurry jet erosion method. [Figure 5] 10 is a graph schematically showing other measurement results obtained by the micro-slurry jet erosion method. [Figure 6] FIG. 10 is a perspective view schematically illustrating a modified example of the removing step. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0010] Fig. 1 is a perspective view schematically showing a coating layer removal method according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view schematically showing a resin structure. Resin structure 1 is suitable for use in vehicle windows and the like.

[0011] As shown in FIG. 2, the resin structure 1 includes a substrate layer 10 and a coating layer 20.

[0012] The base layer 10 is made of a resin. The base layer 10 may be optically transparent. In this embodiment, the base layer 10 is made of a polycarbonate resin.

[0013] The coating layer 20 is provided on the surface of the substrate layer 10. The coating layer 20 may include a blackout layer, an adhesive layer, a hard coat layer, or the like.

[0014] The coating layer removal method in this embodiment is a method for removing the coating layer 20 from the resin structure 1. The coating layer removal method includes a measuring step, a determining step, and a removing step.

[0015] In the measurement step, the thickness of the coating layer 20 is measured by detecting the boundary 15 (see FIG. 2) between the substrate layer 10 and the coating layer 20. For example, in the measurement step, as shown in FIG. 3, the boundary 15 is detected based on the micro-slurry jet erosion method (MSE method) using an MSE testing device 200. As shown in FIGS. 4 and 5, the micro-slurry jet erosion method continuously acquires the wear rate in the depth direction of the resin structure 1. In the measurement step, the depth of the boundary 15, i.e., the thickness of the coating layer 20, is measured based on the change in the wear rate.

[0016] For example, boundary 15 may be defined as an inflection point in the measurement results as shown in FIG. 4. In the example shown in FIG. 4, coating layer 20 is composed of a hard coat layer. The hard coat layer is made of a hard coat material containing, for example, an acrylic component including urethane (meth)acrylate, an inorganic component including colloidal silica with a (meth)acryloyl group, and a polymerization initiator. Boundary 15 in FIG. 4 is an inflection point where the wear rate increases. The location where the wear rate increases corresponds to the fragile layer between coating layer 20 and substrate layer 10. If the location where the wear rate increases (the fragile layer) has a range of thicknesses, the measurement point of the fragile layer closest to the substrate layer may be considered boundary 15.

[0017] Furthermore, boundary portion 15 may be defined based on the measurement results shown in Fig. 5. In the example shown in Fig. 5, coating layer 20 is also composed of a hard coat layer. In the example shown in Fig. 5, coating layer 20 composed of a hard coat layer includes an inner layer provided on the surface of substrate layer 10 and an outer layer provided on the surface of the inner layer. For example, the inner layer is composed of an acrylic layer containing an acrylic resin, and the outer layer is composed of a silicone layer containing silicone.

[0018] In addition to the micro-slurry jet erosion method, the measurement process may also employ other methods, such as film thickness measurement using an optical interference film thickness meter, microscopic observation after cutting out a cross section, an IR method based on the deterioration of resin due to infrared irradiation, or a cross-sectional nanoindentation method based on the depth of indentation of an indenter into the cross section of resin structure 1.

[0019] In the determination step, the high-pressure water conditions are determined based on the relationship between the thickness of the coating layer 20 to be removed, the high-pressure water conditions capable of removing the coating layer 20 having that thickness, and the thickness of the coating layer 20 measured in the measurement step. A pre-prepared map may be used as the relationship. The map shows the relationship between the thickness of the coating layer 20 and the high-pressure water conditions required to remove the coating layer 20 of that thickness. The map includes information such as the pressure of the high-pressure water, the distance between the nozzle 100 and the resin structure 1, the movement speed of the nozzle 100, and the amount of high-pressure water. A relational expression showing the relationship between the thickness of the coating layer 20 to be removed and the high-pressure water conditions capable of removing the coating layer 20 having that thickness may be used as the relationship. In this case, the high-pressure water conditions are determined by inputting the thickness of the coating layer 20 measured in the measurement step into the relational expression. As shown in FIG. 1 , high-pressure water 102 is sprayed from the nozzle 100.

[0020] In the removing step, based on the conditions determined in the determining step, high-pressure water 102 is sprayed from nozzle 100 to remove coating layer 20 from resin structure 1. After the removing step, whether or not coating layer 20 remains may be confirmed visually, or the presence or absence of the coating layer may be confirmed scientifically by FT-IR measurement, or may be detected by imaging with an imaging device.

[0021] As described above, in the method for producing resin structure 1 according to the present embodiment, the thickness of coating layer 20 is detected by detecting boundary 15 between base layer 10 and coating layer 20 in the measurement step, and coating layer 20 is removed using high-pressure water under conditions determined based on the thickness and the map. This makes it possible to both prevent damage to base layer 10 and prevent insufficient removal of coating layer 20.

[0022] 6, the removing step may use a pressing member 300 that presses down the resin structure 1. In the example shown in Fig. 6, a roller that can convey the resin structure 1 while pressing it down is used as the pressing member 300. The pressing members 300 are provided on both sides of the nozzle 100 in the direction in which the nozzle 100 moves relative to the resin structure 1.

[0023] In this embodiment, even if the resin structure 1 is slightly curved, the resin structure 1 becomes roughly flat by pressing the resin structure 1 with the pressing member 300, thereby preventing insufficient removal of the coating layer 20 due to variations in the distance between the nozzle 100 and the resin structure 1.

[0024] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0025] [Aspect 1] A method for removing a coating layer from a resin structure including a substrate layer made of a resin and a coating layer provided on a surface of the substrate layer, the method comprising: a measuring step of measuring a thickness of the coating layer by detecting a boundary portion between the substrate layer and the coating layer; a determining step of determining the conditions of the high-pressure water sprayed from the nozzle based on a relationship between the thickness of the coating layer and the conditions (pressure of the high-pressure water, distance between the nozzle and the workpiece, moving speed, and water amount) of the high-pressure water, and the thickness of the coating layer measured in the measuring step; a removing step of removing the coating layer from the resin structure by spraying the high-pressure water from the nozzle based on the conditions determined in the determining step.

[0026] In this coating layer removal method, the thickness of the coating layer is detected by detecting the boundary between the substrate layer and the coating layer in the measurement process, and the coating layer is removed using high-pressure water under conditions determined based on the thickness and the map, making it possible to both prevent damage to the substrate layer and prevent insufficient removal of the coating layer.

[0027] [Aspect 2] 2. The coating layer removal method according to aspect 1, wherein the measuring step detects the boundary portion based on a micro-slurry jet erosion method.

[0028] In this embodiment, it is possible to detect the boundary relatively easily and with high accuracy.

[0029] [Aspect 3] 3. The coating layer removing method according to claim 1, wherein the removing step uses a pressing member that presses down the resin structure.

[0030] In this embodiment, even if the resin structure is curved, the resin structure becomes generally flat by pressing the resin structure with the pressing member, thereby preventing insufficient removal of the coating layer due to variations in the distance between the nozzle and the resin structure.

[0031] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0032] 1 resin structure, 10 base material layer, 15 boundary portion, 20 coating layer, 100 nozzle, 102 high-pressure water, 200 MSE test device, 300 holding member

Claims

1. A method for removing a coating layer from a resin structure including a substrate layer made of a resin and a coating layer provided on a surface of the substrate layer, the method comprising: a measuring step of measuring a thickness of the coating layer by detecting a boundary portion between the substrate layer and the coating layer; a determining step of determining the conditions for the high-pressure water based on a relationship between the thickness of the coating layer and the conditions for the high-pressure water to be sprayed from the nozzle, and the thickness of the coating layer measured in the measuring step; a removing step of removing the coating layer from the resin structure by spraying the high-pressure water from the nozzle based on the conditions determined in the determining step.

2. 2. The coating layer removal method according to claim 1, wherein the measuring step detects the boundary portion based on a micro-slurry jet erosion method.

3. The coating layer removing method according to claim 1 or 2, wherein the removing step uses a pressing member that presses down the resin structure.

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