JP2015132528A - Coating material for reinforced plastic composite structure, reinforced plastic composite structure on which coating material is applied, and deterioration detection method using coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material for detecting deterioration of a reinforced plastic composite structure, a reinforced plastic composite structure on which the coating material is applied, and a deterioration detection method using the coating material.SOLUTION: The reinforced plastic composite structure comprises: a first coating layer 3 formed on a front face of the reinforced plastic composite structure, including a first coating material of high elasticity in which a fluorescent dye emitting light by excitation light is mixed and which can extend without breaking even when a crack 11 is generated in a substrate 1 of the reinforced plastic composite structure; and a second coating layer 4 formed on the first coating layer 3, including a second coating material of low elasticity in which a shielding material for shielding the excitation light is mixed, and which generates a crack 41 according to the crack 11 generated in the substrate 1. Impact of generation of the crack 11 generates the crack 41 only in the second coating layer 4. When the reinforced plastic composite structure is irradiated with the excitation light, fluorescent dye in the first coating layer 3 is exposed to the excitation light coming through the crack 41 to emit light. Thus, it is possible to detect the crack 11 generated in the substrate 1 located inward from a reinforced resin layer 2 in which no damage occurs.

Description

  The present invention relates to a paint for detecting cracks occurring with time in a reinforced plastic composite structure, a reinforced plastic composite structure to which a paint is applied, and a deterioration detection method using the paint.

  Conventionally, reinforced plastic composite pipes have been used for sewerage, agricultural water, rainwater drainage, and the like. Reinforced plastic composite pipes or Fiberglass Reinforced Plastic Mortar Pipes (hereinafter referred to as “FRPM pipes”) are formed by forming a reinforced resin layer made of a plurality of glass fiber reinforced plastics on the inner and outer side surfaces of a base made of resin mortar and the like. Due to the combined characteristics of the base material that is resistant to compression and the reinforced resin layer that is resistant to tension, the strength can be ensured even when the tube wall is thin, and because of its light weight, it is easy to construct and has excellent total cost. It is a pipe. In recent years, large-diameter FRPM pipes having a diameter of 2 to 3 m have been buried in the ground as pipes for agricultural water, particularly in cold regions, and the piping distance is expected to increase in the future.

  The problem here is the inspection work of the FRPM pipe. As described above, the glass fiber reinforced plastic forming the reinforced resin layer of the FRPM tube has a very high strength and a high toughness. For example, the resin mortar of the base is cracked, resulting in a large impact resulting therefrom. Even when added to the reinforced resin layer, in most cases, the reinforced resin layer does not crack. In other words, it is reasonable to think that the deterioration state of the base of the FRPM tube cannot be confirmed by visual inspection of the appearance.

  Effective means for this problem include a hammering test and an ultrasonic flaw detection described below. The hammering inspection is a method in which an operator hits the surface of a structure to be inspected and detects a space or crack due to deterioration in the base body by the hammering sound. Since the distinction of the hitting sound is based on the subjective judgment of the worker, the inspection result may vary depending on the worker's safety awareness and physical condition. In addition, long-term work in a dark and narrow space has a great physical and mental burden. In addition, the hammering test is not efficient and the inspection cost is high, and agriculture may be affected if water distribution is interrupted for a long period of time.

  In ultrasonic flaw detection, a part called a probe that transmits or receives ultrasonic waves is attached to the structure to be inspected, and the ultrasonic waves propagated from the probe to the inside of the structure When there is a foreign object, it is reflected there, and the reflected ultrasonic wave (echo) is received by the probe again, and the time it takes for the ultrasonic wave to return as an echo is measured, and the distance that the ultrasonic wave has moved within the structure is determined. This is an inspection that can detect the occurrence and location of internal cracks and the like.

  In this way, the subjective judgment based on the hammering sound of the worker has made it possible to obtain an objective inspection result by the ultrasonic flaw detection apparatus, but the inspection efficiency is not much different from that of the hammering inspection. There is no advantage in the inspection period and the burden on the operator.

  In addition, in the patent document 1, the present inventor extends without breaking even when a fluorescent dye that emits light by excitation light is mixed on the surface of a civil engineering such as a tunnel or the base of a building structure and a crack occurs in the base. A highly elastic first coating layer and a shielding material that prevents transmission of excitation light are mixed on the first coating layer, and when a crack is generated in the substrate, the crack is generated following the crack. After forming the elastic second coating layer, the structure is irradiated with excitation light, and the excitation light passes through the crack generated in the substrate after the formation of the coating layer from the crack generated in the second coating layer. Thus, there is provided an inspection method characterized by detecting the first coating layer by emitting light.

  However, even if a crack occurs in the base of the FRPM tube, in most cases, the reinforced resin layer covering the surface does not crack. In addition, since a water-based paint is used for the coating layer formed by this inspection method, it is not suitable for an FRPM pipe for agricultural water that is always exposed to water. Furthermore, in addition to the load due to water pressure, the pebbles and the like that flow may collide with the coating layer of the FRPM tube, so that the coating layer is required to have a strength that can withstand the use environment.

JP 2013-83493 A

  In view of the above-described problems, an object of the present invention is to apply a coating material or a coating material used for coating a reinforced plastic composite structure that can easily and quickly detect cracks occurring with time in the reinforced plastic composite structure. Another object of the present invention is to provide a deterioration detection method using a reinforced plastic composite structure and a paint.

  The present inventor has made further studies to solve the above problems, and as a result of repeated trial and error, attention has been paid to the fact that a crack is generated in the substrate of the reinforced plastic composite structure and a very large impact is generated at the same time. It is thought that cracks can be generated in the second coating layer that is the outermost surface of the reinforced plastic composite structure by impact, and the present invention described below has been completed by embodying and developing this idea. .

≪Paint≫
The coating material of the present invention is mixed with a fluorescent material that emits light by excitation light, and a highly elastic first coating material that extends without breaking even when a crack occurs in the substrate, and a shielding material that blocks transmission of excitation light. And a low-elasticity second coating material that follows a crack when the substrate is cracked, and the first coating layer is coated on the reinforced resin layer to form the first coating layer. None, a coating material characterized in that the second coating layer is applied onto the first coating layer to form a second coating layer. As described above, even if cracks occur in the substrate of the reinforced plastic composite structure, in most cases, cracks do not occur in the high-strength reinforced resin layer. However, it is necessary to cause cracks in the weak second coating layer made of the second paint due to a large impact generated at the same time as cracks occur in the substrate. It is also necessary that the highly elastic first coating layer made of the first paint can withstand the impact. As a result, when the reinforced plastic composite structure is irradiated with excitation light, the fluorescent dye of the first coating layer emits light upon receiving irradiation of excitation light entering from the crack of the second coating layer, and the reinforced resin is free from damage. Cracks generated in the substrate inside the layer can be easily detected. Once the paint according to the present invention is finished into a reinforced plastic composite structure, the paint composition is removed by physical or chemical damage of the paint composition due to human accidents or fire, or repair work due to subsequent maintenance. Except that, it functions in the long term.

≪Reinforced plastic composite structure≫
Further, the reinforced plastic composite structure of the present invention has a highly elastic first structure in which a fluorescent dye that emits light by excitation light is mixed on the reinforced resin layer and extends without breaking even when a crack occurs in the substrate. When a first coating layer made of one coating material and a shielding material for blocking the transmission of excitation light are mixed on the first coating layer and a crack occurs in the substrate, a crack is generated following the crack. And a second coating layer made of a low-elasticity second coating material.

≪Degradation inspection method for reinforced plastic composite structure≫
The degradation inspection method for a reinforced plastic composite structure according to the present invention breaks even when a fluorescent dye that emits light by excitation light is mixed on the reinforced resin layer of the reinforced plastic composite structure and a crack occurs in the substrate. A step of forming a first coating layer made of a highly elastic first coating material without extending, and a shielding material that prevents transmission of excitation light is mixed on the first coating layer and a crack occurs in the substrate And a process of forming a second coating layer made of a low-elasticity second coating that cracks following this, and a deterioration inspection pre-process, and irradiating the reinforced plastic composite structure with excitation light, A crack generated in the substrate after the pre-degradation inspection step is detected by causing the first coating layer to emit light by passing excitation light from the crack generated in the second coating layer.

  In the above invention, the step of photographing the irradiated surface with a CCD camera while irradiating the reinforced plastic composite structure after the deterioration inspection pre-process with the CCD camera, and the step of obtaining image processing data from the photographed image, By comparing the image processing data with the past image processing data and digitizing the degree of progress of deterioration, the degree of deterioration can be managed by observing the numerical fluctuation.

≪Others≫
The reinforced plastic composite structure here is a composite structure in which a high-strength reinforced resin layer made of a plurality of glass fiber reinforced plastics is formed on the surface of a relatively hard and brittle substrate made of resin mortar, It includes the above-mentioned tubular FRPM tube, a plate-like reinforced plastic composite plate, and the like. FRPM pipes are used for sewerage, agricultural water, rainwater drainage, and hydraulic power generation hydraulic pipes, and reinforced plastic composite plates are used for pit covers and bridge inspection walkways of power plants and substations. In addition, a structure in which a high-strength reinforced resin layer made of glass fiber reinforced plastic, etc., is formed only on the inner diameter side surface to reinforce existing PC pipes (precast concrete pipes). include.

  The paint used for the coating of the reinforced plastic composite structure according to the present invention is generated on the substrate covered with the reinforced resin layer only by irradiating the reinforced plastic composite structure with excitation light such as ultraviolet light or blue visible light. Cracks can be easily detected. Thereby, the inspection period can be shortened, and the burden on the worker can be greatly reduced. Further, it is possible to carry out a detailed inspection such as a hammering inspection limited to the specified crack generation range of the substrate. The same effect can be obtained by the reinforced plastic composite structure to which the paint is applied and the deterioration detection method using the paint.

It is a photograph which shows a mode that the crack generate | occur | produced in the base | substrate of the reinforced plastic composite pipe. It is sectional drawing which shows the cross-section before crack generation | occurrence | production of a base | substrate. It is sectional drawing which shows the light emission state of the 1st application layer after the crack generation | occurrence | production of a base | substrate. It is a plane photograph which shows a mode that the crack generate | occur | produced in the 2nd application layer. It is a top view photograph of the crack part of the 2nd application layer which received and emitted ultraviolet light.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a photograph showing a crack in a substrate 1 of a reinforced plastic composite tube before application of a paint according to the present invention. As can be seen from FIG. 1, the reinforced resin layer 2 is not damaged even if a crack occurs in the substrate 1. FIG. 2 is a cross-sectional view showing a cross-sectional structure of the base 1, the reinforced resin layer 2, the first coating layer 3, and the second coating layer 4 before the base 1 is cracked. The layer 2 is formed, the first coating layer 3 is formed on the reinforced resin layer 2, and the second coating layer 4 is formed on the first coating layer 3. FIG. 3 is a cross-sectional view showing a light emission state of the first coating layer 3 after the crack 11 is generated in the substrate 1.

  As shown in FIG. 2, before the crack is generated, the excitation light is blocked from being transmitted by the shielding material in the second coating layer 4, so that it does not reach the lower first coating layer 3 and the first coating layer 3 Does not emit light.

  As shown in FIG. 3, when a crack 11 occurs with a large impact in the substrate 1, no cracks occur in the high-strength reinforced resin layer 2 and the highly elastic first coating layer 3, but a hard and brittle second coating layer. In FIG. 4, a crack 41 is generated by the propagated impact. Due to the generation of the crack 41, the excitation light passes through the crack 41 and reaches the lower first coating layer 3, so that the crack portion emits light by the fluorescent dye. Since the light emission is bluish white, an operator can easily find a crack even in a dark place.

  Examples of the substrate 1 include those that are relatively hard and brittle and easily cracked, such as resin mortar, cement mortar, slate plate, gypsum board, extruded plate, concrete, metal, glass, porcelain tile, plastic, and ceramics. It is done.

  Specifically, the reinforced resin layer 2 has a layer in which a fiber reinforced plastic in which glass fiber is mixed in an unsaturated polyester resin or the like is laminated, and a surface protective layer on the outermost surface. In addition to glass fiber, carbon fiber, high-strength resin fiber, or the like can be used as a reinforcing material for fiber-reinforced plastic.

  The first coating layer 3 is required to have a high elasticity having a large ductility and not to be cracked by an impact when a crack occurs in the substrate. Examples of the first paint forming the first coating layer 3 include ethylene vinyl acetate copolymer-based, acrylic polymer-based, vinyl acetate homopolymer-based, polyurethane-based, and SBR-based water-based elastic paints that can be applied to the reinforced resin layer. Appropriate plasticizers are applied to various water-based emulsion paints (water-based elastic paints such as vinyl acetate, styrene-butadiene, and acrylic), polyurethane resin, epoxy resin, acrylic silicon resin, and fluororesin. What is necessary is just to prepare and use a characteristic by adding. Examples of the plasticizer include phthalic acid esters, aliphatic dibasic acid esters, glycol ester acids, phosphate ester glycols, and epoxy plasticizers. In particular, polyurethane resin paints, epoxy resin paints, acrylic silicon resin paints, fluororesin paints, and the like that have good adhesiveness with the unsaturated polyester resin constituting the reinforced resin layer 2 are suitable. Furthermore, an additive having weather resistance, heat resistance, flame retardancy, etc. can be appropriately added to the first paint in accordance with the function of the reinforced plastic composite structure, but it is important that the ductility is not lowered by the addition. It is. A commercially available elastic paint can be used as the first paint.

  In order to suppress the occurrence of cracks, an elastic filler such as a urethane chip, an ethylene-vinyl acetate copolymer chip, or a rubber chip can be added to the elastic paint.

  Here, the first coating layer 3 needs to be mixed with a fluorescent dye that emits light when irradiated with excitation light. As the excitation light, ultraviolet light or blue visible light having a wavelength of 500 nm or less can be used. When the wavelength is longer than 500 nm, the fluorescent dye cannot emit light. An ultraviolet lamp, an ultraviolet LED, or the like can be used as the ultraviolet light source, and a blue LED light can be used as the blue visible light source.

  In the present application, the term “fluorescent dye” is a generic term for fluorescent pigments and fluorescent dyes. Examples of fluorescent pigments include phosphorescent materials and fluorescent materials, and examples of fluorescent dyes include fluorescent whitening materials. The phosphorescent material continues to emit light even after the excitation light such as ultraviolet rays and blue-based visible light disappears. As this phosphorescent material, an inorganic pigment of alumina oxide can be used, and various rare earth-based materials can be used. A phosphorescent material (strontium aluminate + europium, neodymium dope, calcium aluminate + europium, dysprosium dope, etc.), zinc sulfide + copper dope, or the like can be used.

  In addition, the fluorescent material emits fluorescence when stimulated by excitation light, and the light emission stops when the stimulation is stopped. As this fluorescent material, organic and inorganic substances having fluorescence themselves, and further fluorescent dyes Conventionally used pigments can be used, such as pigments obtained by dissolving and curing in a thermosetting resin. Examples include fluorescein-based, stilbene-based, various rare earth fluorescent materials, and sulfides such as barium, strontium, and zinc.

  A fluorescent whitening material is a material that selectively absorbs ultraviolet rays in sunlight and converts it into visible purple to blue visible light, which is then emitted. For example, a general fluorescent whitening material such as a diaminostilbenzyl sulfonic acid derivative system, a bisstyryl biphenyl derivative system, a coumarin derivative system, a pyrazolone derivative system, a bisbenzoxazole derivative system, or a naphthalimide derivative system may be used. it can.

  In contrast to the flexible and highly ductile first coating layer 3, the second coating layer 4 has low ductility, low elasticity, and is hard and brittle. The second coating layer 4 is subjected to the second coating by an impact generated when a crack occurs in the substrate 1. It is also necessary for the layer 4 to crack. At the same time, it is necessary to have sufficient water resistance and strength to withstand load caused by water pressure and collision of pebbles. As the second coating material forming the second coating layer 4, a polyurethane-based, epoxy resin-based, acrylic silicon resin-based, and fluororesin-based coating that can be applied to the first coating layer 3 is mixed with a curing agent blending ratio. The properties may be adjusted and used by increasing the number of crosslinkable functional groups by increasing the amount of crosslinkable functional groups. Further, by using the same paint as the first paint and the second paint and increasing the addition amount of the curing agent or reducing the addition amount of the plasticizer, necessary characteristics can be obtained. Curing agents such as epoxies, azolidines, oxazolines, hydrazines, isocyanates, polyamines, imidazoles, and acid anhydrides can be appropriately selected and used according to the type of paint. Similarly, an additive having weather resistance, heat resistance, flame retardancy, abrasion resistance and the like can be appropriately added to the second paint in accordance with the function of the reinforced plastic composite structure. This also makes the second coating layer 4 hard and brittle with low ductility. A commercially available hard paint can be used as the second paint.

  If a highly transparent paint that suppresses discoloration due to ultraviolet rays or aging deterioration is used for the first paint and the second paint, the deterioration state of the reinforced resin layer 2 to which the paint is applied can also be visually confirmed.

  The second coating layer 4 needs to contain a shielding material that prevents transmission of excitation light. An ultraviolet absorber, an ultraviolet scattering agent, or the like can be used as the shielding material. Examples of the ultraviolet absorber include octyl methoxycinnamate, oxybenzene, t-butylmethoxydibenzoylmethane and the like. Examples of the ultraviolet scattering agent include titanium oxide and zinc oxide. These ultraviolet absorbers and ultraviolet scatterers may also have an effect of shielding blue visible light.

  As a method for applying the first coating material and the second coating material, for example, various methods such as a spray coating method, a roller coating method, a brush coating method, and a dipping method can be appropriately selected according to the shape of the structure. After coating, the coating layer can be formed by drying at room temperature or by heating and drying at 40 to 200 ° C.

  Since it is important that the first coating layer 3 does not generate cracks, a certain amount of thickness is required to provide elasticity. The second coating layer 4 needs a certain thickness in order to improve the wear resistance. In order to obtain a predetermined film thickness, the coating and drying steps can be repeated multiple times.

  A reinforced resin layer 2 made of glass fiber reinforced plastic was formed on a substrate 1 made of resin mortar which is a structural member of the FRPM tube. As the first coating material, a polycarbonate-based polyurethane resin coating material was used in which a large amount of plasticizer was added to increase ductility and zinc sulfide was added as a fluorescent material. Moreover, the thing which added the hardening | curing agent to the epoxy resin coating material as a 2nd coating material and reduced ductility, and added the oxybenzene as this to the ultraviolet absorber was used.

  First, coating and drying of the first paint are repeated three times on the surface of the reinforced resin layer 2 to form the first coating layer 3, and then coating and drying of the second paint are repeated three times on the second coating layer 4. Formed. The test piece thus prepared was refracted by an external force, and a crack was generated in the substrate 1. At that time, a plurality of cracks as shown in FIG. When this was irradiated with ultraviolet rays in a dark place, linear blue-white light as shown in FIG. 5 appeared. It was confirmed that linear light emission was emitted corresponding to the cracks generated in the substrate 1.

  The crack detected by inspecting the structure as described above is photographed with a CCD camera, image processing data is obtained from the photographed image, and this image processing data is digitized and compared with the numerical values obtained in the past. By doing so, it is possible to grasp and manage the degree of progress of deterioration. For example, when an operator holds an excitation light source such as ultraviolet rays and irradiates the inside of the FRPM tube, the irradiated portion is photographed and recorded by a CCD camera, so that the inspection can be performed in a short period of time. The equipment to be used is an LED light that emits ultraviolet rays, a CCD camera, and an apparatus for recording the position data of the worker, so that inspection equipment can be manufactured at low cost. Since the distance cannot be measured with a CCD camera, it is necessary to input the cross-sectional shape of the FRPM tube as a parameter necessary for image processing.

  For example, if the image processing data is captured per unit area (for example, every 1 m in the length direction of the RPMM tube) with dot data that emits light due to cracks in white and other portions are captured in black, the total of white dot data is approximately It becomes the area of the crack part. If the white dot data is 15000 between 20 and 21 m from the entrance and the next measurement data after 1 year is 20000, it is determined that the crack has increased by 5000 dots. By examining the measurement results, it is possible to make a more detailed inspection plan, such as performing a hammering inspection and a close visual inspection on a portion with a large amount of fluctuation.

  As described above, the present invention has a great advantage that it can perform two kinds of inspections, that is, an analog inspection by an operator and a digital inspection using a CCD camera. The fact that cracks occurring in plastic composite structures can be inspected quickly and easily contributes greatly to industrial development. According to the visual inspection method in the technology according to the present invention, that is, the method in which the inspector simply detects the crack while irradiating the reinforced plastic composite structure with a light source that generates ultraviolet light or blue-based visible light. The possibility of detecting deterioration and deformation of the composite structure is greatly improved.

  You can obtain digital data that is not overlooked by the conventional analog inspection method, or contribute to preparation materials for analog detailed inspection based on the obtained digital data. It can be said that the method can be changed greatly. Even when an emergency inspection is required, such as during a natural disaster, the results can be quantified without human differences.

DESCRIPTION OF SYMBOLS 1 Base | substrate, 2 Reinforcement resin layer, 3 1st application layer, 4 2nd application layer, 11 Crack of base | substrate, 41 Crack of 2nd application layer

Claims (4)

A coating applied to a reinforced plastic composite structure comprising a substrate and a reinforced resin layer formed on one side or both sides of the substrate,
A high-elasticity first paint that is mixed with a fluorescent dye that emits light by excitation light and extends without breaking even when a crack occurs in the substrate;
A low-elasticity second paint in which a shielding material that blocks transmission of excitation light is mixed and cracks are generated following the occurrence of cracks in the substrate;
Consists of
The first paint is applied on the reinforced resin layer to form a first application layer,
A coating material, wherein the second coating material is applied onto the first coating layer to form a second coating layer. A reinforced plastic composite structure comprising a substrate and a reinforced resin layer formed on one side or both sides of the substrate,
A first coating layer made of a highly elastic first coating material, which is mixed with a fluorescent dye that emits light by excitation light and extends without breaking even when a crack occurs in the substrate;
A second material made of a low-elasticity second coating material is mixed with a shielding material for preventing transmission of excitation light on the first coating layer, and a crack is generated following the occurrence of a crack in the substrate. A coating layer;
A reinforced plastic composite structure characterized by comprising: A method for inspecting deterioration of a reinforced plastic composite structure comprising a substrate and a reinforced resin layer formed on one side or both sides of the substrate,
Forming on the reinforcing layer a first coating layer made of a highly elastic first coating material mixed with a fluorescent dye that emits light by excitation light and extending without breaking even when a crack occurs in the substrate; ,
A second material made of a low-elasticity second coating material is mixed with a shielding material for preventing transmission of excitation light on the first coating layer, and a crack is generated following the occurrence of a crack in the substrate. Having a pre-degradation inspection step comprising a step of forming a coating layer,
The reinforced plastic composite structure is irradiated with excitation light to cause the first coating layer to emit light by causing excitation light to pass through the crack generated in the substrate after the pre-degradation inspection step. A method for inspecting deterioration of a reinforced plastic composite structure, characterized by In the reinforced plastic composite structure after the deterioration inspection pre-process,
Photographing the irradiated surface with a CCD camera while irradiating excitation light;
Obtaining image processing data from the captured image;
A step of comparing the image processing data with past image processing data and quantifying the degree of progress of deterioration,
The deterioration inspection method for a reinforced plastic composite structure according to claim 3, wherein the progress of deterioration is managed by observing the numerical fluctuation.