JPH0699131A - Execution control of paint - Google Patents

Abstract

PURPOSE:To prevent the remaining of a solvent in a film and to aim at the perfectness of painting by applying painting to a test piece under the same conditions as the painting to an object to be painted to confirm the hardness of the film on the test piece and further ageing the painted test piece when curing is insufficient before entering the painting work of the next process. CONSTITUTION:In a heavy corrosion-proof painting system, an inorg. or org. zinc rich primer layer 2 is applied to an object 1 to be painted as the lowermost layer and a mixed coat layer 3 and first and second topcoat layers 4, 5 are successively applied on the primer layer using paint such as epoxy paint, polyvinyl chloride paint or polyurethane paint. In this paint execution control method, a test piece other than the object 1 to be painted is prepared and painting is applied to the test piece under the same conditions as the painting to the object 1 to be painted to confirm the hardness of the film on the test piece and, when curing is insufficient, the painted test piece is further aged before the painting work of the next process is performed. Since the hardness of the test piece painted under the same conditions is measured, painting can be applied to the object 1 to be painted without damaging the object.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to coating electric equipment such as generators, electric motors and transformers, or equipment such as steam turbines, water turbines, rolling mills, tanks and pools.
The present invention relates to a construction control method for heavy anticorrosion coating using a zinc rich primer as an undercoat.

[0002]

2. Description of the Related Art Conventionally, as a coating system using a zinc rich primer as an undercoat, an inorganic zinc rich primer composed of an alkali silicate or an alkyl silicate, a large amount of zinc dust and a slight color developing agent, or an epoxy. Indoor, heavy-corrosion coating is performed by undercoating an organic zinc-rich primer with a large amount of zinc powder and a slight color-developing agent added to chlorinated rubber, etc., and then epoxy-based paint, polyurethane-based paint, vinyl chloride-based paint, etc. It is applied to equipment installed in.

Zinc-rich primer has an excellent anticorrosion effect due to the electrochemical sacrificial anticorrosion effect of zinc, but since the coating film formed is porous, it is epoxy-based paint, polyurethane-based paint, vinyl chloride-based paint. A thin coating of paint is applied and sealing is performed. The paint for the purpose of this sealing treatment is called a mist coat. Further, a conventional general coating system is to apply an epoxy-based coating, a polyurethane-based coating, a vinyl chloride-based coating or the like on top of this and put it into practical use.

As a method for applying a coating system using a zinc rich primer as an undercoat, there is, for example, "a heavy anticorrosion coating method for equipment (Japanese Patent Laid-Open No. 59-150579)".

[0005]

In the prior art, the construction of a mist coat from a zinc rich primer (ZRP),
The coating from the mist coat to the next process such as top coating is controlled by the curing period from the previous process. That is, the mist coat is constructed with zinc rich primer.
It is defined by time, such as one week after the completion of the construction. However, in this case, depending on the environmental conditions at the time of curing, the solvent may remain in the coating film because it moves to the next step in a state where it is not sufficiently cured. When the solvent remains, there is a problem that the residual solvent volatilizes after use and causes swelling of the coating film, impairing the anticorrosion effect. In the conventional coating method, after the completion of all coating steps, the hardness of the final layer may be confirmed before use, or after the ZRP layer is applied, the hardness may be confirmed before moving to the next step,
It is not stipulated that the hardness should be checked in all painting processes.
Therefore, the possibility of the solvent remaining as described above remains.

Further, as described above, the zinc rich primer
Since the layer is porous, a mist coat is applied for the purpose of sealing treatment, but in the prior art, only the appearance state is confirmed after the application, and the thickness of the mist coat layer is controlled. There wasn't.

In this case, there is a problem in that the sealing process is moved to the next step while the sealing process is insufficient, the adhesion of the zinc rich primer layer is lowered, and blisters are likely to occur.

[0008] Taking anti-corrosion coating of a suppression pool in a nuclear power plant as an example, after the start of plant operation,
The suppression pool will be replaced once every 10 years. At the time of water replacement, the state of the coating film is observed and if blistering occurs, repair coating is performed. Since the anticorrosion effect of the coating film is expected for a long period such as 10 years in this way, it is necessary to perform sufficient coating control at the time of initial construction to provide a coating film having durability.

When performing the above mist coat film thickness control,
Regarding the film thickness of the mist coat, the amount of paint actually applied cannot be grasped only by measuring the film thickness of the coating object after drying because the mist coat penetrates into the zinc-rich primer layer after construction.

An object of the present invention is to solve the above-mentioned problems, and in a coating system using a zinc rich primer as an undercoat, 1. Thoroughly control the hardness of the coating film for each coating process, and 2. It is intended to provide a coating system having excellent durability by controlling the film thickness after the mist coat construction.

[0011]

The first means of the present invention is to:
In order to achieve the above-mentioned first object, an inorganic or organic zinc rich primer is applied to the lowermost layer of the object to be coated,
In a heavy-duty anti-corrosion coating system in which epoxy-based paint, vinyl chloride-based paint, polyurethane-based paint, etc. are applied on top of it, prepare test pieces other than the above-mentioned object to be coated, and apply the same coating to the object to be coated. It is characterized in that the test piece is coated under the conditions of (1), the coating film hardness of the test piece is confirmed, and if curing is insufficient, further curing is performed and then the coating operation of the next step is started.

In order to achieve the above-mentioned second object, the second means of the present invention is to coat an object to be coated with an inorganic or organic zinc-rich primer as the lowermost layer, and then apply an epoxy-based paint or chloride to it. In a heavy-duty anti-corrosion coating system in which paints such as vinyl-based paints and polyurethane-based paints are repeatedly applied, a test piece other than the above-mentioned object to be coated at the time of construction of a mist coat for the purpose of sealing treatment of the zinc-rich primer layer Prepare a test piece, apply the test piece under the same conditions as the application to the coating object, check the film thickness of the coating film of the test piece, and if the film thickness is insufficient,
It is characterized in that the coating work of the next step is started after further painting.

[0013]

According to the first means of the present invention, the hardness of the coating film is measured after completion of each coating step and before proceeding to the next step. By checking the hardness of this by a simple method such as the pencil hardness method, the hardness can be managed without impairing workability. When measuring hardness, prepare a test piece in addition to the object to be coated, apply the test piece to the object under the same conditions as the coating, and measure the hardness of this test piece. There is no turning on.

According to the second means, the film thickness of the mist coat layer is properly controlled, and the decrease in the adhesive strength of the zinc rich primer layer is prevented. At that time, prepare a test piece in addition to the object to be coated, apply it to the object at the same time as coating, and measure the film thickness after drying.
By applying to a test piece that does not have a layer, the net mist coat film thickness can be measured.

The test piece is constructed at the same time as the object to be coated and under the same conditions, and the coating state on the object to be coated is reproduced. Since it is only necessary to prepare a small test piece, there is no problem with an increase in the number of painting steps. Further, since the same operator paints the test piece at the same time, it is possible to reproduce the state of the coating film of the coating object.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a sectional view of a coating system using a zinc rich primer as an undercoat. 1 is an object to be coated, 2 is a zinc coat primer layer, and 3 is a mist coat layer.
Reference numeral 4 indicates the first layer of the top coat, and 5 indicates the second layer.

FIG. 2 shows the coating process of this coating system. As shown in the figure, preparation of the material to be used, pretreatment of the steel material surface, adjustment of the base material, and inspection are performed, and first, the zinc rich primer layer is applied to the object to be coated. Next, the mist coat, the first layer of the top coat, and the second layer are applied in this order. After blasting the object to be coated, an inorganic zinc rich primer is applied.

FIG. 3 shows an airless spray coating machine.
In FIG. 3, 6 is a spray gun, 7 is a hose, 8 is a suction hose, 9 is a hydraulic part, 10 is a pressure adjusting valve, 11 is a relief valve, 12 is a motor, 13 is a switch, 14
Is a paint base, and 15 is a paint. The airless spray is a method in which paint is accumulated on the paint base 14, hydraulically pressurized and supplied to the spray gun 6, and the paint is ejected from the spray gun 6 to coat an object. The operator grips the spray gun with his hand and moves the gun while maintaining a distance of about 30 cm from the target object to spray the paint. Inorganic zinc-rich primer (Dainippon Paint's ZETAL OLT, etc.) is a special thinner by mixing a zinc powder with a spotting agent.
After diluting with, paint on the object using an airless spray or the like. After curing for 3 days or more after coating, the degree of curing of the zinc rich primer layer is confirmed by the method shown in FIG. Reference numeral 16 in the figure denotes absorbent cotton. The primer layer after drying is rubbed with absorbent cotton several times to observe the change in color of the absorbent cotton.
A sample of absorbent cotton showing the relationship between the degree of curing of the primer layer and the degree of adhesion to the absorbent cotton is prepared in advance, and the degree of curing is confirmed by comparing the colors of this sample and the absorbent cotton of 16. FIG. 5 shows the criteria for determining the degree of cure. If the curing degree is 4 or more, the next step is performed. When the curing degree is 3 or less, the curing is insufficient, so the curing is further carried out and the curing degree confirmation test is cleared before proceeding to the next step.

FIG. 6 shows a cross section of the coating film after the mist coat is applied. Mist coat (Dainippon Paint Eponics 310AP
The primer or the like) is constructed by adding a pigment to an epoxy resin, diluting it with a dedicated thinner, and then using an airless spray or the like. In the mist coat construction, a test piece, for example, a small metal plate 17 is prepared together with the object, and is also applied to this.
The metal plate 17, which is a test piece, is applied simultaneously with the object to be coated and under the same conditions, and the coating state on the object to be coated is reproduced. Since it is sufficient to prepare a small metal plate or the like for the test piece, an increase in the number of painting steps does not pose a problem. or,
Since the same operator paints the test piece at the same time, it is possible to reproduce the state of the coating film of the coating object.

After coating, the film is cured for 3 days or more, and the thickness of the coating film on the metal plate is measured with an electromagnetic film pressure gauge. FIG. 7 shows the measurement principle of the electromagnetic film thickness meter. When iron is brought close to the tip of the coil with an iron core, the inductance of the coil changes in response to a slight change in the distance. This change is used to measure the thickness of the film. If the film thickness is a predetermined thickness (for example, 60 μm) or more, the process proceeds to the next step. When the film thickness is insufficient, the coating is further repeated, and after confirming that the film thickness is not less than the predetermined value, the process proceeds to the next step. Further, the hardness is confirmed by the pencil hardness method before proceeding to the next step.

FIG. 8 shows an outline of the pencil hardness method. As shown in FIG. 8, hold the pencil at an angle of about 45 degrees, and push it against the test surface as hard as possible so that the shin cannot be broken, and then push it forward about 1 cm at a uniform speed in front of the tester to scratch the test surface.
The extrusion speed is about 1 cm / s.

After each scratch, the tip of the pencil shin is newly sharpened, and the test is repeated 5 times with a pencil having the same density symbol. If you want to evaluate the damage of the coating film, it is 2 in 5 tests.
If no breakage that reaches the base material or undercoating film of the test piece is found more than once, replace it with a pencil having a higher density symbol and perform the same test. Record the density symbol that is one step lower than the pencil concentration symbol.

In the case of evaluating scratches on a coating film, if scratches are not recognized on the coating film twice or more in five tests, the pencil is replaced with a higher density symbol and the same test is performed. Find a pencil with more than two scratches on the film and record the density one step below the pencil's density symbol. If the hardness is equal to or higher than a predetermined hardness (for example, 2B), the process proceeds to the next step.

The first layer is coated with the same type of paint as the mist coat by using an airless spray or the like. After curing for 24 hours or more, the hardness of the coating film is confirmed by a pencil hardness method, and after reaching a predetermined hardness (for example, 2B) or more, the next step is performed. If the hardness is lower than the predetermined hardness, the curing is not sufficient, so that the film is further cured before proceeding to the next step.

After the first layer is applied, the same kind of paint is further applied as the second layer.

After the completion of the construction, it is cured for about 30 days and the hardness is confirmed by the same method as in FIG. The pencil hardness is about H. It is put to practical use after confirming that the curing is sufficient by this hardness measurement.

When measuring the hardness of the coating film by the pencil test method, it is desirable that the test piece is coated simultaneously with the object to be coated under the same conditions as in the measurement of the mist coat.

[0029]

As described above, according to the present invention, after the completion of each coating step, the hardness of the coating film is confirmed and the process proceeds to the next step. In addition, since the thickness of the mist coat is measured using a test piece when the mist coat is applied, it is necessary to thoroughly control the thickness of the mist coat and put the coating system with excellent durability into practical use. You can

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cross-sectional view of a heavy anticorrosion coating system using a zinc rich primer.

FIG. 2 is a diagram showing a coating flow of a heavy anticorrosion coating system using a zinc rich primer.

FIG. 3 is a diagram showing an outline of an airless spray machine.

FIG. 4 is a diagram showing a method for confirming the curing degree of the zinc rich primer layer.

FIG. 5 is a diagram showing the evaluation criteria for the curing degree of the zinc rich primer layer.

[Fig. 6] Cross-sectional view of coating film after mist coating

FIG. 7 is a diagram showing the measurement principle of an electromagnetic film thickness meter.

FIG. 8 is a diagram showing a test state of a pencil hardness method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Object to be coated 2 ... Zinc rich primer layer 3 ... Mist coat layer 4 ... 1st layer 5 ... 2nd layer 6 ... Spray gun 7 ... Hose 8 ... Suction hose 9 ... Hydraulic part 10 ... Pressure adjusting valve 11 ... Relief valve 12 ... Motor 13 ... Switch 14 ... Paint base 15 ... Paint 16 ... Absorbent cotton 17 ... Test piece 18 ... Iron core coil 19 ... Coating film 20 ... Indicator 21 ... Power supply

Claims (3)

[Claims] 1. A heavy-duty anti-corrosion coating in which an inorganic or organic zinc-rich primer is applied to the lowermost layer of an object to be coated, and epoxy-based paint, vinyl chloride-based paint, polyurethane-based paint or the like is applied on top of it. In the system, prepare a test piece other than the object to be coated, coat the test piece under the same conditions as the coating on the object to be coated, confirm the coating film hardness of the test piece, and if the curing is insufficient Is a method for managing the construction of paints, which is characterized in that the coating work of the next process is started after further curing. 2. A heavy-duty anti-corrosion coating system in which an inorganic or organic zinc-rich primer is applied to the lowermost layer of an object to be coated, and epoxy paint, vinyl chloride paint, polyurethane paint, etc. At the time of construction of the mist coat for the purpose of sealing the zinc rich primer layer, a test piece is prepared in addition to the above-mentioned object to be coated, and the test piece is coated under the same conditions as the coating on the object to be coated. Then, the film thickness of the coating film of the test piece is confirmed, and if the film thickness is insufficient, further coating is carried out, and then the coating work of the next step is started. 3. A heavy anticorrosion coating system in which an inorganic or organic zinc-rich primer is applied to the lowermost layer of an object to be coated, and epoxy paint, vinyl chloride paint, polyurethane paint, etc. In the above, the construction management of the paint is characterized in that the hardness of the coating film in the previous step is confirmed before starting the coating operation in the next step, and if curing is insufficient, it is further cured before entering the coating step in the next step. Method.