JP2004033942A - Coating method of counter weight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a counter weight excellent in design properties and a coating film performance. <P>SOLUTION: The coating method of a cast counter weight disposed at the rear part of a turning body of a conveying machine or a construction machine is constituted of (1) a step for applying a primer coating onto a cast casted for the counter weight; (2) a step for carrying out puttying; (3) a step for spray-coating with an isocyanate curing acrylic resin based organic solvent coating at a spotted shape to form a projection pattern coating part; (4) and then, a step for uniformly spray-coating a surface of the projection pattern coating part formed in the step of (3) and a non-coated part with a top coat colored organic solvent coating. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for coating a counterweight made of a casting disposed on a rear part of a revolving structure such as a crane, a construction machine such as a power shovel, and a transport machine such as a forklift, and more particularly, paints a coating on a counterweight made of a casting in a patchy manner. The present invention relates to a coating method in which a convex-painted portion is formed, and then the paint is uniformly applied to the convex-painted portion and the unpainted portion to form the surface in an uneven shape.
[0002]
[Prior art]
Conventionally, as a method of coating a counterweight made of a casting disposed at the rear of a revolving structure of a transport machine or a construction machine, a primer coating was performed after allowing the casting cast for the counterweight to cool, or the casting was allowed to cool. After that, putty is put on the required part, and after this putty, the primer is applied. Next, putty is applied, and the entire surface is applied by spray putty coating or putty coating. Polishing was further performed, and after polishing, a top coat was applied.
[0003]
The above-mentioned conventional coating process has a drawback that the number of processes is large and it takes time to commercialize the product, so that it is impossible to respond to an urgent order or the stock increases.
[0004]
In order to reduce the number of such coating steps, it is conceivable to omit the spray putty coating step, the putty coating step, and the polishing step, which are very laborious and time-consuming, in the above-mentioned coating step. However, in a coating system in which such a step is omitted, the gas generated from the cavity of the casting causes defects such as blisters and wedges in the coating, resulting in poor coating film appearance and coating film performance. Under the influence of Yuzu skin, there was a defect that the smoothness of the top coat was deteriorated, and the appearance and performance of the coat were poor.
[0005]
[Problems to be solved by the invention]
The present invention relates to a conventional method for coating a counterweight made of a casting disposed at the rear part of a revolving structure of a transporting machine or a construction machine. In the process, for example, an isocyanate-curable acrylic resin-based organic solvent paint is spray-painted to form a convex-painted portion, and then a top-coat colored organic solvent paint is uniformly applied to the surface of the convex-painted portion and the unpainted portion. The present invention provides a coating method that can omit the spray putty coating step, the putty coating step, and the polishing step that have been conventionally performed by spray coating.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, in particular, to form a convex painted portion by spray coating isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner, The inventors have found that the above-mentioned object can be achieved by uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the painted portion and the unpainted portion, and have completed the present invention.
[0007]
Thus, a first invention is a method for coating a counterweight made of a casting disposed at the rear part of a revolving structure of a transport machine or a construction machine,
(1) a step of applying a primer coating to a casting cast for a counterweight;
(2) a step of putting putty,
(3) a step of spray-coating an isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner to form a convex-painted portion;
(4) Next, a step of uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the convex-painted portions and the unpainted portions formed in the step (3),
And a method for coating a counterweight.
[0008]
Further, a second invention is a method of coating a cast counterweight disposed at a rear portion of a revolving structure of a transport machine or a construction machine,
(1) a step of applying a primer coating to a casting cast for a counterweight;
(2) a step of spray-coating an isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner to form a convex-painted portion;
(3) Next, a step of uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the convex-painted portions and the unpainted portions formed in the step (2),
And a method for coating a counterweight.
[0009]
ADVANTAGE OF THE INVENTION According to this invention, in a coating process, the conventional spray putty coating process, putty coating process, and its grinding | polishing process can be omitted, and the number of processes can be reduced and the operation can be simplified. In addition, the surface of the counterweight can be formed in a gently uneven shape, and the design can be made excellent and the coating film performance can be excellent.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
As a method of coating a cast counterweight disposed at the rear of the revolving structure of the transporting machine or the construction machine in the present invention,
(1) a step of applying a primer coating to a casting cast for a counterweight;
(2) a step of putting if necessary
(3) a step of spray-coating an isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner to form a convex-painted portion;
(4) Next, a step of uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the convex-painted portions and the unpainted portions formed in the step (3),
It consists of each process.
[0011]
This is shown in the cross-sectional view of FIG. 1 illustrating the completed paint state. A in the figure is a casting cast for a counterweight. B in the figure is a portion where the primer coating performed in the above step (1) is applied. In the figure, C is a convex pattern painted portion formed in the above step (3). D in the figure is a portion where the top-coating colored organic solvent paint is uniformly spray-coated.
[0012]
In the step (1) of applying a primer to a casting, a conventionally known primer can be used as a primer applied to a casting cast for a counterweight. Examples of such a primer include an epoxy resin primer, a polyester resin primer, and a phenol resin primer. As the primer, those using water or an organic solvent as a dispersion medium are preferable.
[0013]
In this primer coating, the casting cast for the counterweight is usually applied after being cooled to room temperature or outdoor temperature, but the temperature of the casting is relatively high (about 100 ° C. or lower) in the cooling stage. Even primer coating can be performed.
[0014]
Before the primer coating, if necessary, the casting may be subjected to a smoothing treatment by blasting, putty coating or the like.
[0015]
This primer coating is usually preferably performed by spray coating. The coating thickness of the primer is not particularly limited, but is preferably about 20 to 100 μm on average, and particularly preferably about 30 to 80 μm on average in terms of dry thickness. The drying of the primer may be appropriately selected depending on the type of the primer, but it is generally considered that the drying at room temperature for 10 minutes to 7 days is sufficient.
[0016]
Next, in the step (2) of putting putty, the step (1) is performed as necessary after the step of applying the primer coating. Steps 3) and 4) are carried forward.
[0017]
Putting in the above step (2) is likely to cause defects such as a decrease in the finished appearance of the overcoated film and a decrease in the performance of the coated film when a coating film defect occurs after the primer coating. Then, it is performed for the purpose of repairing coating film defects in the primer coating. As a type of putty used for putting, a conventionally known putty can be used. Specifically, for example, it is preferable to use a cold-setting polyester resin putty in which unsaturated polyester is blended with a peroxide catalyst. The putty can be applied by, for example, spraying or spatula.
[0018]
Next, in the step (3), the isocyanate-curable acrylic resin-based organic solvent paint is spray-painted to form a convex-painted portion. As for the type, a conventionally known type can be used. Specifically, for example, an organic solvent paint obtained by blending a polyisocyanate curing agent with an acrylic polyol resin can be suitably used. In addition, a curing accelerator, a coloring agent, a filler, other additives, and the like can be added to the paint as needed.
[0019]
This acrylic resin-based organic solvent paint can be applied by appropriately selecting a spray coater and coating conditions so as to form a convex pattern paint portion. Examples of the spray coating equipment and the coating conditions include a spray coating model, a nozzle type and a diameter, a spray pattern width, a coating supply pressure, a coating amount, a coating temperature, a coating humidity, a coating speed, a coating operation width, and the like. Further, in the present invention, it is particularly preferable to partially apply the coating by a pressurized spray coating method.
[0020]
Examples of the coating equipment include, for example, MSA-512 coating gun manufactured by Devilbiss Co., Ltd. as a coating gun, and W100-152 manufactured by Anest Iwata Co., Ltd. And the like.
[0021]
Further, as an example of the coating conditions, the gun air pressure is 0.01 to 10.0 kg, the coating air pressure is 0.01 to 150.0 kg, the atomizing nozzle is adjusted as needed, and the air nozzle is adjusted as needed. Adjustment and the like.
[0022]
The convex pattern painted portion to be painted is not particularly limited, but it is preferable that the number of ball-shaped patterns having an average diameter of about 2.0 to 20.0 mm is large.
[0023]
To dry the painted convex painted part, if the convex painted part is dissolved and swelled by the top coat colored organic solvent paint to be painted next, it is dried under conditions that do not cause deformation or deterioration in the convex painted part. Good. Specifically, it is preferable to carry out, for example, at a temperature of 100 ° C. or less for 1.0 minute to 5 hours, particularly for 1.0 minute to 1 hour.
[0024]
Next, in the step (4), a colored organic solvent paint is applied over the surface of the convex pattern painted portion formed by the spray coating in the step (3) and the unpainted portion where the convex pattern painted portion is not formed. Is a step of uniformly spray coating.
[0025]
As the top-coating colored organic solvent paint, a conventionally known one can be used, but a paint in which a coloring pigment is blended with the above-mentioned isocyanate-curable acrylic resin-based organic solvent paint is particularly preferable. Examples of color pigments include, for example, inorganic pigments such as carbon black, titanium oxide, titanium yellow, and graphite: quinacridone-based pigments such as quinacridone red, azo-based pigments such as pigment red, phthalocyanine-based phthalocyanine blue, and phthalocyanine-based phthalocyanine green; Organic pigments such as Hansa Yellow, Pigment Yellow L, Benzidine Yellow, Permanent Yellow, etc .; and scaly metallic powders such as aluminum, copper, mica-like iron oxide, bronze, stainless steel and the like. The compounding ratio of the color pigment can be such that the color of the above-mentioned convex-painted portion can be seen through, or that the color of the convex-painted portion can be completely hidden and not seen at all.
[0026]
The mixing ratio of the color pigment varies depending on its own properties, for example, hiding power, specific gravity, etc., and is usually about 0.5 to 300 parts by weight, preferably 3 to 150 parts by weight, per 100 parts by weight of the resin solids. It is blended at a ratio of about parts by weight. In addition to the above, for example, extender pigments such as barium sulfate, calcium carbonate, clay, zinc white, and silica may be used in combination.
[0027]
The top-coating organic solvent paint is uniformly spray-painted on the convex-painted portions and the unpainted portions. The spray coating equipment and coating conditions are not particularly limited, and are conventionally known. For example, spray coating models, nozzle types and diameters, spray pattern widths, paint supply pressures, coating amounts, and coatings Temperature, painting humidity, painting speed, painting operation width and the like are listed. In addition, in the present invention, it is particularly preferable to apply the entire surface by a pressure-feed spray coating method.
[0028]
Examples of the coating device and the paint pumping device are not particularly limited, but the same devices as those described in the spray coating for forming the convex pattern coating portion in the step (3) can be used.
[0029]
The applied top-coating colored organic solvent paint may be appropriately selected and dried according to the type of paint used.
[0030]
By performing as described above, in the coating process, the spray putty coating process, the putty coating process, and the polishing process, which are conventionally performed, can be omitted, and the number of processes can be reduced to simplify the operation. Moreover, the surface of the counterweight is spray-painted to form a patchy convex-painted portion, and the surface of the convex-painted portion and the unpainted portion is evenly spray-painted, thereby reducing the surface of the counterweight. It can be formed in a gently uneven shape, and can have excellent design properties and coating film performance.
[0031]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0032]
(Example 1)
Spray-painted in a spot (ball) shape on a casting plate with a spray of urethane PG-80 white (manufactured by Kansai Paint Co., Ltd., trade name, two-pack acrylic urethane paint, spray-painted solid content of 57% by weight) under the following conditions. After drying at 20 ° C. for 30 minutes, a uniform paint for urethane PG-80 yellow (manufactured by Kansai Paint Co., Ltd., trade name, two-pack acrylic urethane paint, spray coating solid content: 36% by weight) is uniformly applied by spraying. And dried at 20 ° C. for 30 minutes.
[0033]
3. Coating equipment and coating conditions for the paint of Rethane PG-80 white: MSA-512 (painting gun) manufactured by Devilbiss, W100-152 (paint feeding equipment) manufactured by Anest Iwata, gun air pressure 0.5 kg, coating air pressure 4. 0 kg, two rotations of the atomizing nozzle, and two rotations of the air nozzle.
[0034]
The painted convex-painted portion had many ball-shaped patterns having an average diameter in the range of 2.0 to 20.0 mm, and exhibited good design properties.
[0035]
Further, the performance of the obtained convex pattern painted portion was evaluated as follows. (* 1) The adhesion is 100, and the score is 0 indicating good. (* 2) The volatile-resistant oil is recognized as having no change in 4 hours or more, and a good result is obtained. (* 3) As for the salt spray resistance, the result is ○ without any rust or blister.
[0036]
(Example 2)
Spray paint is applied to the casting plate in the form of spots (balls) with a paint of urethane PG-80 yellow (trade name, manufactured by Kansai Paint Co., Ltd., trade name, two-pack acrylic urethane paint, spray coating solid content: 57% by weight) under the following conditions. After drying at 20 ° C. for 5 minutes, a uniform paint for urethane PG-80 yellow (manufactured by Kansai Paint Co., Ltd., trade name, two-pack acrylic urethane paint, spray coating solid content: 36% by weight) is uniformly applied by spraying. And dried at 20 ° C. for 30 minutes.
[0037]
Coating equipment and coating conditions for the paint of the urethane PG-80 yellow: a Sumitomo 3M Body Shutz spray gun (coating gun), a gun air pressure of 1.0 kg, and a gun nozzle 2 revolutions.
[0038]
The painted convex-painted portion had many ball-shaped patterns having an average diameter in the range of 2.0 to 20.0 mm, and exhibited good design properties.
[0039]
Further, the performance of the obtained convex pattern painted portion was evaluated as follows. (* 1) The adhesion is 100, and the score is 0 indicating good. (* 2) The volatile-resistant oil is recognized as having no change in 4 hours or more, and a good result is obtained. (* 3) As for the salt spray resistance, the result is ○ without any rust or blister.
[0040]
(Comparative Example 1)
A uniform paint of urethane PG-80 yellow (Kansai Paint Co., Ltd., trade name, two-pack type acrylic urethane paint, spray coating solid content: 39% by weight) is applied to the casting plate by spraying to form spots (balls). Then, the mixture was dried at 20 ° C. for 30 minutes, and then the same paint for uniform application of the same urethane PG-80 yellow was uniformly applied by spraying and dried at 20 ° C. for 30 minutes.
[0041]
The painted convex pattern painted portion had small convexity and was inferior in design.
[0042]
The test methods performed in the above (Example 1), (Example 2), and (Comparative Example 1) are as follows.
[0043]
(* 1) Adhesion: Performed by a grid tape method specified in JIS-K-5600-5.6. However, the gap between cuts was 1 mm. The evaluation was performed according to the regulation. Evaluation is made on a 6-point scale from 0 to 5, and the better the score, the better the result.
[0044]
(* 2) Volatile resistance oil: The test was performed according to JIS-K-5600-6.1. However, petroleum benzene was used as the volatile oil. In the evaluation, wrinkles, swelling, cracking, and peeling were not observed in the coating film, and the degree of gloss change, discoloration, and softening as compared with the coating film before the test was not bad, and was evaluated as good.
[0045]
(* 3) Salt spray resistance: A test was conducted for 120 hours according to JIS-K-5600-7.1. The degree of rust and blistering of the test piece was evaluated. ○ indicates no rust or swelling, Δ indicates slight rust or swelling, and X indicates remarkable rust or swelling.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a method for coating a counterweight according to the present invention.
[Explanation of symbols]
A: Cast, B: Primer coated part, C: Convex painted part, D: Part uniformly spray painted.

Claims (2)

A method of coating a cast counterweight placed at the rear of a revolving structure of a transport machine or a construction machine,
(1) a step of applying a primer coating to a casting cast for a counterweight;
(2) a step of putting putty,
(3) a step of spray-coating an isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner to form a convex-painted portion;
(4) Next, a step of uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the convex-painted portions and the unpainted portions formed in the step (3),
A method for painting a counterweight, comprising: A method of coating a cast counterweight placed at the rear of a revolving structure of a transport machine or a construction machine,
(1) a step of applying a primer coating to a casting cast for a counterweight;
(2) a step of spray-coating an isocyanate-curable acrylic resin-based organic solvent paint in a patchy manner to form a convex-painted portion;
(3) Next, a step of uniformly spray-coating a top-coating colored organic solvent paint on the surfaces of the convex-painted portions and the unpainted portions formed in the step (2),
A method for painting a counterweight, comprising:

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