JP2008032430A - Method for diagnosing deterioration of film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diagnostic method for deterioration of film, capable of quantitatively diagnosing deterioration of a film which cannot be determined visually. <P>SOLUTION: The method for diagnosing the deteriorated state of a resin film 1 that is a diagnostic object comprises irradiating the resin film 11 with a light L emitted from a light source 12; inputting reflected light L1 from the resin film 11 into a spectrometer 12; measuring the absorbance of a specific wavelength resulting from OH group that forms a deteriorating factor of the resin film 11; and quantitatively determining the degree of deterioration of the resin film from the absorbance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating film deterioration diagnosis method, and more particularly to a coating film deterioration diagnosis method for quantitatively diagnosing coating film deterioration using a spectroscopic analysis method.

  Conventionally, the deterioration diagnosis method of a resin coating film has mainly been a method of measuring impedance, and other methods such as gloss measurement, visual observation, and peeling method.

  The impedance method is a method for detecting the influence of the load on the coating film through which the electric signal has passed by using the electrode probe on the transmitting side and the receiving side and transmitting and receiving the electric signal between the two electrode probes. The impedance method is useful for diagnosing deterioration of a coating film having a rough surface or a coating film having a bend because the portion of the probe that contacts the resin coating film is small.

  Gloss measurement is a method of visually observing the surface of a resin coating film and judging coating film deterioration based on the glossiness of the surface.

  The peeling method is a method of diagnosing the degree of coating film deterioration by peeling the coating film from the substrate using a tensile tester and measuring the adhesion strength of the coating film.

  There is also a degradation diagnosis system in which visual inspection is automated by a CCD camera and image processing (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2001-194383 JP 2001-266121 A Takashi Kaneda, Yukihiro Ishikawa, Taketo Uomoto “Concrete Engineering” vol.43, No3, p.37-44

  However, the conventional coating film deterioration diagnosis method is not quantitative. In particular, in the impedance method, the result greatly varies depending on the environment at the time of diagnosis, such as being greatly affected by moisture. In addition, since the impedance method changes depending on the contact with the electrode probe, it is necessary to apply a gel agent for contact to the coating film, and it is necessary to drop the coating film on the ground portion.

  Gloss measurement is affected by dirt on the surface of the coating film and lacks quantitativeness. Other methods are also qualitative diagnosis methods, and have a large error depending on the person to be measured.

  The system automated by image processing is a method of calculating the area ratio of rust and the like that has appeared on the metal that is the base material in the first place, and is different from the method of diagnosing the deterioration state before rust occurs. With this method, it is not possible to diagnose whether or not repairs should be made before rusting because, for example, rusting impairs the aesthetic appearance. Further, after rusting, steps such as rust removal must be performed at the time of repair, and repair costs are increased.

  Accordingly, an object of the present invention is to provide a coating film deterioration diagnosis method capable of solving the above-described problems and quantitatively diagnosing coating film deterioration that cannot be visually recognized.

  In order to achieve the above object, the invention of claim 1 is a method of diagnosing the deterioration state of a resin coating film to be diagnosed, irradiating the resin coating film with light emitted from a light source, The reflected light is input into the spectroscope, and the spectroscope measures the absorbance at a specific wavelength caused by the OH group that causes the deterioration of the resin coating, and quantitatively determines the degree of deterioration of the resin coating from the absorbance. This is a coating film deterioration diagnosis method to be obtained.

  The invention of claim 2 is the coating film deterioration diagnosis method according to claim 1, wherein the resin coating film is any one of a urethane resin coating film, a chlorinated rubber resin coating film, and a fluorine resin coating film.

  The invention of claim 3 irradiates light in the near-infrared region from a light source, and has at least 1 absorbance that appears in the vicinity of wavelengths of 1.21 μm, 1.41 μm, 1.93 μm, 2.17 μm, and 2.29 μm. The method for diagnosing coating film deterioration according to claim 1 or 2, wherein one method is used.

  According to a fourth aspect of the present invention, the spectroscope is output from a diffraction grating that divides the reflected light at a predetermined wavelength, a light reflection deflecting unit that selectively deflects the dispersed light, and the light reflecting deflection unit. A light detector for detecting light, and the absorbance is obtained from a difference between the light intensity at a specific wavelength caused by the OH group and the light intensity in a wavelength band before and after the specific wavelength. It is a coating-film deterioration diagnostic method of description.

  According to a fifth aspect of the present invention, the spectroscope is divided into a light guide that introduces light emitted from the light source as reference light, and a diffraction grating that separates the reference light and reflected light introduced from the light guide for each predetermined wavelength. The light reflection deflecting means for selectively deflecting the reflected light and the light detector for detecting the light output from the light reflecting deflection means, and the absorbance is the light intensity of the specific wavelength based on the reflected light and the reference light. It is a coating-film degradation diagnostic method in any one of Claims 1-3 calculated | required by measuring the difference with the light intensity of the specific wavelength based on.

  According to a sixth aspect of the present invention, the spectroscope is connected to a scanning device that sequentially takes the light reflected at different positions on the resin coating film into the spectroscope, and the reflected light is sequentially input to the spectroscope via the scanning device. The coating film deterioration diagnosis method according to claim 1, wherein the absorbance due to the OH group is detected to obtain a two-dimensional distribution of coating film deterioration.

  According to this invention, the outstanding effect that deterioration of the coating film which cannot be discerned visually cannot be diagnosed quantitatively is exhibited.

  As a result of studying the spectrum of the coating film reflected light using a spectroscopic analysis method, the present inventors have found that the coating film reflected light has an absorption peak at a specific wavelength depending on the state (degree) of coating film deterioration. It was. Then, by reaching that these absorption peaks are attributed to OH groups, by measuring the absorbance of OH groups, which are components that cause deterioration of the coating film (factors present on the surface and inside of the deteriorated coating film) The inventors have conceived that the coating film deterioration state can be quantitatively diagnosed, and have reached the present invention.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing a preferred embodiment of a diagnostic apparatus used in a coating film deterioration diagnosis method according to the present invention.

  A diagnostic device 10 shown in FIG. 1 measures a light source 12 that irradiates light on the surface of a resin coating film (hereinafter referred to as coating film) 11 to be diagnosed, and the absorbance at a specific wavelength of reflected light reflected by the coating film 11. And a data processing device 15 connected to the spectrometer 13.

  Between the light source 12 and the coating film 11, a light guide for guiding the light source emitted light L may be provided in the coating film 11. Between the coating film 11 and the spectroscope 13, the reflection reflected by the coating film. A light guide for inputting the light L1 to the spectroscope 13 may be provided. Examples of the light guide include a lens, a mirror, and an optical fiber. In the present embodiment, an optical fiber 14 is connected to the light source 12 and the spectroscope 13 respectively. A data processing device 15 is connected to the spectrometer 13. The data processing device 15 processes (calculates) the result output from the spectroscope 13 and displays it.

  The light source 12 preferably has a wavelength range of the light emitted from the light source L in the range of 0.9 to 2.5 μm (near infrared region), such as a lamp (for example, a halogen lamp), an LED, a heating element that emits near infrared rays, and the like. Is mentioned.

  The coating film 11 is formed by, for example, forming a resin coating layer having a thickness of about 2, 30 μm on the surface of a metal (for example, iron) substrate 16 such as a bridge or a wall of a structure. Examples of the resin coating film 11 diagnosed by this coating film deterioration diagnosis method include a urethane resin coating film, a chlorinated rubber resin coating film, or a fluorine resin coating film.

  Now, in the coating film deterioration diagnosis method of the present embodiment, the coating film 11 is irradiated with the light L emitted from the light source 12, the reflected light L1 from the coating film 11 is input into the spectroscope 13, and the spectroscopy is performed. The apparatus 13 is characterized in that the absorbance at a specific wavelength caused by the OH group that causes deterioration of the coating film 11 is measured, and the degree of deterioration of the resin coating film is quantitatively determined from the absorbance.

  The basic principle of the coating film deterioration diagnosis method will be described.

  When the coating film 11 deteriorates due to ultraviolet rays, wind and rain, etc., OH groups and the like can be formed on the coating film surface by hydrolysis or the like. Furthermore, moisture (OH group) permeates between fine cracks formed on the coating surface due to deterioration. On the other hand, these OH groups have an absorption band in the near infrared region between wavelengths of 1 to 2.5 μm.

  Then, if the magnitude | size of absorption by OH group is measured by spectroscopically analyzing the light which reflected and reflected the light to the coating film 11, the degree of coating film deterioration can be quantified. The relationship between the magnitude of absorption and the degree of deterioration (deterioration degree) of the coating is stored in a database in advance, and the magnitude of absorption and the degree of deterioration measured by spectroscopic analysis are compared to make a quantitative diagnosis.

  2 (a) and 2 (b) are absorption spectra showing the relationship between wavelength and absorbance after spectroscopic analysis of a urethane resin coating film after 16 years of exposure.

  As shown in FIG. 2 (a) and FIG. 2 (b), the absorption spectrum of the coating film before exposure (before exposure test, new article) is the entire wavelength range in the near infrared region (0.7 to 2.5 μm). There is almost no light absorption. On the other hand, the absorption spectrum of the coating film after exposure for 16 years has absorption peaks at wavelengths near 1.21 μm, 1.41 μm, 1.93 μm, 2.17 μm and 2.29 μm. It should be noted that the absorption spectrum of the coating film after the exposure shows that the absorbance is generally higher (increased) than the absorption spectrum of the coating film before the exposure. This is because it is lost (reflectance is reduced).

  Therefore, in the present embodiment, the absorption wavelength of at least one peak is selected from the above specific wavelength band, the absorbance at that wavelength is measured, and the measured absorbance is degraded using a database created in advance. By converting into degrees, the degree of deterioration of the coating film can be obtained (estimated) from the absorbance of the light reflected by the coating film 11. Further, the greater the number of absorption peak wavelengths to be selected, the higher the reliability of the estimated deterioration level. Further, the relationship between the absorbance and the degree of deterioration may be obtained using multiple regression analysis or statistical processing such as PLS.

  3 (a) and 3 (b) show that a plurality of coating film samples (samples) were prepared, and the absorbance at a wavelength of 2290 nm of the urethane resin coating film after 16 years exposure was measured for each sample before and after cleaning. The measurement results are shown. In FIG. 3, the coating film surface is the surface on the exposed side, and the coating film back surface is the surface on the side that is not directly exposed (back surface).

  As shown in FIG. 3A and FIG. 3B, when the absorbance of the coating film surface is compared with the absorbance of the coating film back surface, the absorbance of the coating film surface is higher in each sample. From this, it can be seen that the exposed side has a lot of OH groups (moisture) and is significantly deteriorated compared to the back surface of the coating film (inside the coating film).

  FIG. 4 is a graph showing the relationship between the exposure years of the resin coating film and the absorbance. This graph was obtained by measuring the absorbance at a wavelength of 1935 nm of a urethane resin coating film with exposure years of 0 years (new), 6 years, and 16 years.

  As shown in FIG. 4, the absorbance is about 0 for a resin coating film with an exposure period of 0 years, the absorbance is about 0.01 for a resin coating film with an exposure period of 6 years, and the absorbance is about 0.1 for a resin coating film with an exposure period of 16 years. When the value is 015 or more, the relationship between exposure years (deterioration degree) and absorbance is substantially linear.

  Here, the deterioration of the urethane resin coating film has been studied by infrared spectroscopic analysis, and the following deterioration mechanism is considered.

  When the urethane resin coating is exposed for a long time, the urethane bond portion is hydrolyzed as shown in [Chemical Formula 1] due to rain or moisture in the air.

At this time, OH groups are generated. Thereafter, the isocyanate produced in [Chemical Formula 1] is hydrolyzed to produce an amino group.

Further, as shown in [Chemical Formula 3], the ester moiety is hydrolyzed to form a carboxyl group.

  That is, the urethane resin coating film exposed to the atmosphere generates a component having an OH group when the bond is broken by hydrolysis and becomes a low molecule (deteriorates) from a polymer. Therefore, the more the OH groups are generated as the urethane resin coating film is broken and the molecular weight is lowered, the correlation between the degree of deterioration of the resin coating film and the amount of the component having an OH group is generated.

  In addition, it has been confirmed that the absorption band of 3400 cm −1, which is one of the OH group absorption bands in the near-infrared region, increases in absorption as the coating film deteriorates. The absorption band of 3400 cm −1 corresponds to an absorption band of wavelength 1.41 μm in the near infrared region.

  In the polyurethane resin coating film, hydrolysis shown in [Chemical Formula 1] to [Chemical Formula 3] starts from the surface layer, and this is presumed to proceed into the coating film.

  FIG. 5 shows the amide absorption band (CN stretching vibration and NH bond of urethane bonds) while the coating film is being scraped from the surface in order to investigate how much urethane bond hydrolysis has progressed to the inside of the coating film. The ratio (absorbance at 1520 cm -1) and the CH2 deformation vibration at 1520 cm -1 that does not change even when exposed (absorbance ratio on the vertical axis in the figure) are determined from the coating surface. It is the figure which showed the relationship with distance (depth).

  As shown in FIG. 5, both the exposed coating film (exposed part in the figure) and the unexposed coating film (non-exposed part in the figure) show a marked decrease in the amide absorption band on the coating film surface. Thus, it can be seen that hydrolysis of the coating proceeds from the surface of the coating and progress is slow inside.

  In addition, the deterioration of the chlorinated rubber resin coating film is considered to be dechlorinated by ultraviolet rays (see [Chemical Formula 4]), and chlorine reacts with iron and zinc in the pigment, leading to the generation of red rust and white rust. It has been.

  In the deterioration of a chlorinated rubber resin coating film, it is known that the progress of the deterioration depends on the presence or absence of moisture on the surface of the resin coating film, so that moisture promotes the deterioration (see [Chemical Formula 5]).

  6 (a) to 6 (c) and FIGS. 7 (a) to 7 (c), a urethane resin coating sample is placed in a weather meter (environmental acceleration test apparatus), respectively, and 0 hours and 600 respectively. It is a SEM image of the surface of the chlorinated rubber resin coating film when it is allowed to stand for 1200 hours.

  As shown in FIGS. 6 (a) to 6 (c) and FIGS. 7 (a) to 7 (c), according to the observation results (SEM image in the figure) using EPMA (Electron Probe Micro-Analysis). The crack can be recognized on the surface after about 1200 hours of weather meter. Since the inside of the coating film is exposed to the atmosphere by this crack, it is considered that the cross section of the crack becomes the same as the surface, and the deterioration is accelerated. At this time, it is considered that water molecules are fixed to fine cracks (cracks) and exist in a state like pore water, and the OH groups of this water (water like pore water) radiate light in the near infrared region. It is estimated that it will absorb. Since this water has entered a narrow gap, it cannot act freely and is not easily evaporated.

  In this way, OH groups present in the coating include those that are chemically bonded to the coating molecules, water in the state of pore water, water that can move freely (normal moisture), etc. The amount is expected to increase with progress.

  Next, the fact that the specific wavelength is an absorption peak of OH group will be described.

  FIG. 8 is a graph showing the near-infrared spectrum of soil (excerpted from Yukihiro Ozaki and Satoshi Kawada, “The Spectroscopic Society of Japan, Series 32, Near-Infrared Spectroscopy”, 1996, Academic Publishing Center).

  As can be seen from FIG. 8, the absorption bands at wavelengths of 1.41 μm, 1.935 μm, and 2.165 μm have absorption peaks similar to the graphs shown in FIGS. 2 (a) and 2 (b).

  Regarding the absorption band having a wavelength of 1.21 μm and a wavelength of 2.29 μm, vibration of CH is also conceivable. However, according to the results of infrared absorption analysis, it has been confirmed that the absorption of CH becomes smaller as the deterioration progresses, and since no absorption is originally seen in a new state, it is determined that the absorption is not CH. The Therefore, it is predicted that this is an absorption band related to OH groups.

  Hereinafter, the coating film deterioration diagnosis method of the present embodiment will be specifically described.

  As shown in FIGS. 9A to 9C, the optical fiber 61 connected to the light source 12 and the optical fiber 62 connected to the spectrometer 13 are bundled by a single optical fiber cable 63. . For example, the optical fiber cable 63 includes a plurality of output optical fibers 61 that respectively emit the light source emission light L at the cable inner peripheral part, and a plurality of input optical incidents at which the coating film reflected light L1 is incident on the cable outer peripheral part. An optical fiber 62 is provided, and the plurality of optical fibers 61 and 62 are integrally covered. A coating film contacting probe 64 is provided at the tip of the optical fiber cable 63. The probe 64 is for contacting a position on the coating film surface and collecting the reflected light at that position. When the probe 64 is brought into contact with the coating film surface, the input / output light of the optical fibers 61 and 62 is collected. The tip of the optical fiber cable 63 is provided so as to be located a predetermined distance (for example, several mm) away from the surface of the coating film 11 in order to reduce the deviation of the light intensity of the coating film reflected light.

  Further, as shown in FIG. 10, a magnet 65 may be provided around the probe 64 or at the tip (around in the drawing). Since the magnet 65 is fixed to the surface of the coating film 11 because the substrate 16 is a metal, the probe 64 can be fixed to the coating film 11.

  As shown in FIG. 11, the spectroscope 13 is optically connected to the other end side of the optical fiber 62, and from the upstream side in the light propagation direction, the diffraction grating 31, the light reflection deflecting means 32, the aperture 33, and the light collecting means. 34 and the photodetector 35 are provided in this order.

  The diffraction grating 31 is irradiated with the light L1 emitted through the optical fiber 62, reflected, and dispersed for each predetermined wavelength. The light reflection deflecting means 32 is irradiated with the light L1 split by the diffraction grating 31, and is reflected and deflected. As will be described in detail later, the light reflection deflecting means 32 has a MEMS actuator that sweeps and modulates the dispersed light L1 for each predetermined wavelength.

  The aperture 33 is a light-shielding stop that passes / blocks the deflected light L1. When the deflected light L1 is applied to the blocking body 33a, the propagation is blocked. Further, when the deflected light L1 is irradiated toward the opening between the adjacent blocking bodies 33a, the light L1 passes. The shape of the blocking body 33a is not particularly limited, and may be circular instead of rectangular. The opening may be a groove (slit) provided in the blocking body 33a itself.

  The condensing means 34 is a member that condenses the light expanded in the spectroscope 14 onto the photodetector 35, and uses a conventional condensing lens.

  The light detector 35 detects the light L1 collected by the light collecting means 34 and outputs the light intensity of the light L1. The data detector 15 is connected to the photodetector 35 through an AC amplifier or the like.

  A deterioration diagnosis method using the spectrometer 13 of FIG. 11 will be described.

  First, dust and moisture on the surface of the coating film to be diagnosed (here, having a size that can be visually confirmed) are removed. After removing dust and the like, the coating film is irradiated with light from the light source, and the light reflected by the coating film is input to the spectroscope.

  The light L1 that has entered the spectroscope 13 is split into light for each predetermined wavelength by the diffraction grating 31 and travels toward the light reflection deflecting means 32.

  The reflected reflected light L1 is reflected and deflected by the light reflection deflecting means 32. The light reflection deflecting means 32 is, for example, a MEMS programmable diffraction grating, and the MEMS programmable diffraction grating includes a MEMS actuator (hereinafter referred to as MEMS). The light L1 that has reached the MEMS is reflected and deflected at a high speed in a predetermined angle range and travels toward the aperture 33. Due to this reflection and deflection, the light intensity is adjusted for each of the light beams having the dispersed wavelengths in the reflected light L1.

  For example, as shown in FIG. 12A, the MEMS is provided with stationary electrodes 42a... 42n (only 42a is shown in FIG. 12A) on the substrate 41, and each stationary electrode 42a. Moving electrodes 43a... 43n (only 43a is shown in FIG. 12A) are provided. Each moving electrode 43a... 43n is provided so as to be in contact with and separated from each stationary electrode 42a... 42n (movable in the vertical direction in FIG. 12A). Each of the moving electrodes 43a... 43n is provided with leg portions 44a and 44b provided on the substrate 41, an electrode main body portion (mirror portion) 45, and one end fixed to the leg portions 44a and 44b, and the other end. Has flexible connection portions 46a and 46b for suspending the electrode main body 45. By forming the thickness D1 of the flexible connection portions 46a and 46b thinner than the thickness D2 of the electrode body portion 45 (for example, about 1/3), the flexible connection portions 46a and 46b can be bent freely. . The electrode main body 45 is rigid and does not bend. Each stationary electrode 42a ... n is independently connected to control means (for example, a computer (not shown)).

  Each movable electrode 43a... 43n can be driven independently by controlling the voltage (potential difference) between each stationary electrode 42a... 42n and each movable electrode 43a. it can. As a result, the separation distances H1... Hn (only H1 is shown in FIG. 12A) between the stationary electrodes 42a... 42n and the moving electrodes 43a. can do. As for the relationship between the voltage and the separation distances H1... Hn, a calibration curve is prepared in advance, and the separation distances H1. In this way, the separation distances H1... Hn between the stationary electrode and the moving electrode can be freely adjusted steplessly. The MEMS is arranged so that the direction in which the moving electrodes 43a... 43n are arranged and the direction in which the grooves of the diffraction grating 31 are arranged in parallel, and the wavelengths of the light L1 dispersed by the diffraction grating 31 are different. Light is reflected by different moving electrodes. Therefore, the intensity of light passing through the aperture 33 can be adjusted for each wavelength band. Further, the control of each of the MEMS moving electrodes 43a... 43n is performed at high speed and in synchronization with the control means.

  Specifically, as shown in FIG. 12B, by not moving all the moving electrodes 43a... 43n but leaving them apart from the stationary electrodes 42a. In the aperture 33, all light in all wavelength bands (lights 49a to 49c in FIG. 12B) pass. Further, as shown in FIG. 12C, all the moving electrodes 43a... 43n are brought into contact with the stationary electrodes 42a. In (c), the light beams 49 a to 49 c are blocked between the apertures 33. Further, as shown in FIG. 12 (d), a part of the moving electrodes 43a ... 43n is brought into contact with or close to the stationary electrodes 42a ... 42n, and the remaining moving electrodes 43a ... 43n are not moved, By leaving them separated (when adjusting the light intensity), only the light in a certain wavelength band corresponding to the stationary electrode to be brought into contact with or approached (light 49b and 49c in FIG. 12D) adjusts the light intensity. Passed through the aperture 33. Light in a certain wavelength band corresponding to the stationary electrode kept in contact (light 49 a in FIG. 12D) is blocked by the aperture 33.

  The light L1 that has passed through the aperture 33 enters the light collecting means 34. The light L1 incident on the condensing means 34 is condensed, and light for each predetermined wavelength band selected by the upper and lower sides of the moving electrode of the MEMS is received by the photodetector 35. The received light L1 is output to the data processing device 15 as an electrical signal. In the data processing device 15, the absorbance based on the OH group (water) present on the coating film surface and inside is calculated from the electrical signal based on the light L <b> 1.

  At this time, the reflected light L1 is attenuated by the absorption caused by the OH group with respect to the light emitted from the light source L. Here, the absorption intensity absorbed by the OH group is defined as the following formula (1) from the received light intensity received by the photodetector. The absorption intensity handled here is referred to as “absorbance”.

(Absorption intensity) = -log (Reception intensity) (1)
Generally, in order to obtain the absorbance near the absorption wavelength, an absorption spectrum is detected, and the absorbance at a specific wavelength is obtained from the spectrum. In the present embodiment, only the absorbance in the vicinity of the absorption peak wavelength of the OH group is obtained using the spectrometer 13 equipped with MEMS.

  A method for detecting the absorbance of the absorption peak wavelength from the spectrum of the reflected light L1 by the spectroscope 14 will be described using the examples of the absorption spectra shown in FIGS. 12 (a) to 12 (d) and FIG. 13 (a). .

  First, arbitrary light is previously incident on the spectroscope. In the spectroscope 13, incident light is split by the diffraction grating 31, and each split light has a different diffraction angle for each wavelength and is reflected by different moving electrodes 43 a to 43 n when reaching the MEMS. Is done. Therefore, the relationship between the wavelength of the light introduced into the spectroscope 13 and the position of the moving electrodes 43a... 43n, that is, the position of the moving electrode corresponding to the absorption peak wavelength can be known.

  Next, the reflected light L1 reflected by the coating film 11 is input to the spectroscope 13, and only the moving electrode corresponding to the wavelength of the absorption peak of the OH group is turned ON, and the other moving electrodes are turned OFF. Thereby, the light reflected by the OFF moving electrode is blocked by the aperture 33, and only the light reflected by the ON moving electrode reaches the photodetector 35.

  By controlling each of the moving electrodes 43a... 43n, the light intensity of light having a predetermined wavelength can be selectively measured. By using this feature, only the spectrum (absorption peak light intensity) 71 having only a specific wavelength can be extracted and detected from the absorption spectrum 70 of the reflected light L1. Specifically, only the moving electrodes corresponding to the vicinity of the wavelength of the spectrum 71 of the specific wavelength λa are turned on, and all the remaining moving electrodes are turned off. The light detector 35 detects only the light reflected by the ON moving electrode. The photodetector 35 sequentially switches the moving electrodes that are turned on at high speed in order to detect the light reflected by one moving electrode in sequence.

  Unlike the spectrum 70 shown in FIG. 13A, when the light intensity serving as a reference (base) is different before and after the absorption peak as in the spectrum 72 shown in FIG. 13B, the absorbance of the spectrum 72 is changed. The detection is performed by detecting the light intensities B and D of the wavelengths λb and λd, respectively, and using the straight line connecting the light intensities B and D as the base line 73, and the light intensity C at the wavelength λc and the base line 73 of the wavelength λc. The difference from the light intensity E is obtained, and the difference 74 is defined as the absorbance.

  According to the deterioration diagnosis method of the present embodiment, the components having an OH group and the visual inspection can be performed before the whitening, choking, or rust generated when water reaches the base metal. Since it is possible to detect coating film deterioration depending on how much moisture is retained in the coating film, it is possible to diagnose the deterioration state at an earlier stage than the visual test. This leads to early deterioration prediction and diagnostic applications. For example, the remaining life of the coating film can be determined by applying it to a preliminary diagnosis when examining the repair of the coating film.

  In addition, this coating film deterioration diagnosis method can be measured by simple steps such as applying light to the coating film and taking reflections, so it can be easily carried out by anyone, not just workers with deterioration diagnosis experience. be able to. Furthermore, since the OH group content (water content) of the coating film corresponding to the degree of deterioration is detected, the degree of coating film deterioration can be diagnosed quantitatively and measurement with little individual difference can be performed.

  Since the absorbance is measured at high speed using the spectroscope 13 provided with the above-described MEMS, the diagnosis time can be greatly shortened. As a result, a result can be obtained in a short time (about 1 minute) even if the integrated average of absorbance is large, and a diagnosis with reduced errors can be performed.

  In the coating film deterioration diagnosis method of the present embodiment, only the coating film reflected light L1 is input to the spectroscope 13, and the absorbance of the coating film reflected light L1 is determined by the method described in FIG. 13 (a) or FIG. 13 (b). However, the reference beam may be introduced into the spectrometer 13. For example, a new coating film without deterioration is irradiated with the light source emission light L, and the light intensity of the reflected light is measured to obtain the reference light reception intensity.

  At this time, the absorbance (absorption intensity) is defined by the following formula (2).

(Absorption intensity) = -log (Received light intensity) / (Reference received light intensity) (2)
The measured reference received light intensity may be stored in the data processor 15 and used together with the received light intensity of the coating film reflected light L1 detected later to calculate the absorbance, or the reference light detected by the photodetector 35. After adjusting each electrode of the MEMS so that the received light intensity becomes 0, the light intensity of the coating film reflected light L1 may be detected, and the detected light intensity may be set as a difference with respect to the reference received light intensity.

  Also, two sets of light reflection deflecting means 32 and aperture 33 are provided in the spectroscope 13, and simultaneously with the coating film reflected light L1, the light source emission light L is directly input (not reflected by the coating film) as reference light, You may measure the light absorbency of reflected light L1 compared with the light reception intensity | strength of reference light. By introducing the reference light into the spectroscope and obtaining the absorbance of the reflected light L1 while comparing with the reflected light L1, the measurement with the background noise removed can be performed at high speed.

  In the present embodiment, the coating film reflected light L1 is introduced into the spectroscope 13 using the optical fibers 61 and 62 and the probe 64 connected to the optical fibers 61 and 62, but the coating film is used using the scanning device. The reflected light L1 may be introduced into the spectrometer.

  As shown in FIG. 14A, the scanning device 80 is optically connected via the spectroscope 13 and the optical fiber 62, and the inside of the resin coating surface C out of the light reflected from the resin coating surface C. The reflected light from one point (measurement point p) among a plurality of points arranged in sequence is sequentially taken into the spectrometer 13.

  Specifically, as shown in FIG. 14B, the scanning device 80 includes a polygon mirror 81 and a galvano mirror 82. The polygon mirror 81 is a deflector composed of a rotating polyhedron having a series of plane mirrors around a rotation axis. The galvano mirror 82 has a single mirror as an axis, and the rotation angle of the mirror is adjusted according to an electric signal. It is a deflector that can be changed. The polygon mirror 81 rotates about an axis perpendicular to the paper surface in FIG. 14B as a rotation axis, and scans the resin coating surface C in the lateral direction (i direction in FIG. 14A). 14 (b) is configured to rotate about an axis parallel to the middle paper surface as a rotation axis, and to scan the resin coating film surface C in the vertical direction (j direction in FIG. 14 (a)).

  First, the light L is irradiated from the light source 11 to the resin coating surface C. The light L emitted from the light source 11 is reflected by the resin coating surface C and is emitted as reflected light L1. At that time, the scanning device 80 adjusts the angles of the polygon mirror 81 and the galvanometer mirror 82 to capture the reflected light L1 from the measurement point p (1, 1) in the resin coating surface C. Specifically, the optical axis is adjusted so that the optical axis of the reflected light L1 coincides with the polygon mirror 81 and the galvano mirror 82 so that the reflected light L1 enters the optical fiber 62. The reflected light L <b> 1 whose optical axis is adjusted by the scanning device 80 is input to the spectroscope 13 via the optical fiber 62. After the input, the absorbance is obtained by the above-described method, and the optical axis of the polygon mirror 81 is adjusted so that the optical axis of the reflected light L1 matches a different measurement point p (for example, (2, 1)), and the absorbance is measured in the same manner. To do. By repeating the movement of the measurement point (scanning of the resin coating film surface C by the scanning device 80) and the measurement of absorbance, a two-dimensional distribution of coating film deterioration is obtained (displayed on the display of the data processing device 15).

  In this embodiment, a light source such as a halogen lamp is used, and the light source emission light is reflected by the coating film, and the distance is such that the reflected light is recognized by the spectroscope. On the other hand, deterioration diagnosis may be performed by using sunlight as the light source emission light and introducing reflected light from the sunlight coating film into the spectrometer.

It is the schematic which shows the basic composition of the coating-film degradation diagnostic apparatus used for the coating-film degradation diagnostic method which concerns on this invention. It is a figure which shows the relationship between the wavelength of the urethane resin coating film reflected light before exposure (new article) and the urethane resin coating film reflected light after 16 years exposure, and (a) in wavelength 0.9-1.7 micrometer. The relationship with the absorbance is shown, and (b) shows the relationship with the absorbance at a wavelength of 1.7 to 2.5 μm. (A) is a figure which shows the result of having measured the light absorbency of the reflected light (wavelength 2290nm) before the washing | cleaning of the urethane resin coating film after 16-year exposure for every coating-film surface and coating-film back surface, (b), It is a figure which shows the result of having measured the light absorbency of the reflected light (wavelength 2290nm) after washing | cleaning of the urethane resin coating film after 16-year exposure for every coating-film surface and coating-film back surface. It is a figure which shows the relationship between the exposure years of a urethane resin coating film, and the light absorbency of wavelength 1935nm. It is a figure which shows the relationship between the depth of a urethane resin coating film, and an amide absorption band for every exposed part and non-exposed part. It is a SEM image of the surface of a chlorinated rubber resin coating, (a) shows a SEM image after 0 hours of weather meter, (b) shows a SEM image after 600 hours of weather meter, (c) shows 1200 hours of weather meter. A later SEM image is shown. It is a SEM image of the surface of a chlorinated rubber resin coating, (a) shows a SEM image after 0 hours of weather meter, (b) shows a SEM image after 600 hours of weather meter, (c) shows 1200 hours of weather meter. A later SEM image is shown. It is a figure which shows the near-infrared spectrum of soil. (A) is the schematic which shows the coating-film degradation diagnostic apparatus used for the coating-film degradation diagnostic method of suitable one Embodiment, (b) is an expanded sectional view of a probe, (c) The cross section of an optical fiber cable FIG. It is the schematic which shows the more preferable form of the coating-film degradation diagnostic apparatus of Fig.9 (a). It is a transparent perspective view which shows the detail of a spectrometer. It is a schematic diagram of a MEMS actuator, (a) is a cross-sectional view, (b) is a model diagram at the time of all ON, (c) is a model diagram at the time of all OFF, (d) is a model diagram at the time of light intensity adjustment is there. (A), (b) is a figure for demonstrating the method of calculating | requiring the light absorbency of an absorption peak wavelength from an absorption spectrum, respectively. It is the schematic which shows the coating-film degradation diagnostic apparatus used for the coating-film degradation diagnostic method of other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resin coating film diagnostic apparatus 11 Resin coating film 12 Light source 13 Spectrometer 15 Data processing apparatus

Claims (6)

In the method of diagnosing the deterioration state of the resin coating film to be diagnosed,
The resin film is irradiated with light emitted from a light source, and the reflected light from the resin film is input into the spectroscope. The spectroscope is caused by OH groups that cause deterioration of the resin film. A method for diagnosing coating film deterioration, comprising measuring the absorbance at a specific wavelength and quantitatively determining the degree of deterioration of the resin coating film from the absorbance.   The coating film deterioration diagnosis method according to claim 1, wherein the resin coating film is any one of a urethane resin coating film, a chlorinated rubber resin coating film, and a fluorine resin coating film.   The near-infrared light is emitted from the light source, and at least one absorbance that appears at wavelengths near 1.21 μm, 1.41 μm, 1.93 μm, 2.17 μm, and 2.29 μm is measured. Or the coating-film deterioration diagnostic method of 2.   The spectroscope includes a diffraction grating that splits the reflected light at a predetermined wavelength, light reflection deflecting means that selectively deflects the dispersed light, and light that detects light output from the light reflecting deflection means. The coating according to any one of claims 1 to 3, wherein the absorbance is obtained from a difference between light intensity of a specific wavelength caused by the OH group and light intensity in a wavelength band before and after the specific wavelength. Membrane degradation diagnosis method.   The spectroscope includes a light guide for introducing light emitted from a light source as reference light, a diffraction grating for separating the reference light introduced from the light guide and the reflected light for each predetermined wavelength, and wavelength selection for each of the dispersed light. Optically deflecting light deflecting means and a light detector for detecting the light output from the light reflecting deflecting means, and the absorbance is specified based on the light intensity of a specific wavelength based on the reflected light and the reference light The method for diagnosing a coating film deterioration according to any one of claims 1 to 3, which is obtained by measuring a difference from the light intensity of the wavelength. The spectroscope is connected to a scanning device that sequentially takes the light reflected at different positions on the resin coating film into the spectroscope. The method for diagnosing coating film deterioration according to claim 1, wherein the resulting absorbance is detected to obtain a two-dimensional distribution of coating film deterioration.

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