JP2673756B2 - How to paint rail car skins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method for a rail vehicle outer plate, and more particularly to a coating method useful for a new coating, repainting, etc. of a rail vehicle, a high speed running rail vehicle outer panel with significant vibration and shock. It is about.

[0002]

2. Description of the Related Art A rail vehicle outer plate is welded during assembly of a structure in a vehicle manufacturing process, and strain due to heat is generated, so that the outer plate is smoothed and a beautiful outer plate protective coating is formed.
Usually, a series of coating processes such as primer coating for the purpose of rust prevention, putting to obtain a smooth surface, primer surfacer coating, and top coating are carried out.

That is, the outer plate of a railway vehicle body assembled by welding using steel plate, aluminum material, stainless steel material, etc. is first subjected to blast treatment to remove rust and roughen the surface for improving adhesion. A two-pack type epoxy primer is usually airless or air spray coated to a thickness of 40 μm or more and dried to form a primer coating for the purpose of rust prevention.

Next, for the purpose of smoothing the unevenness of the vehicle outer plate, a putty mainly made of unsaturated polyester resin is putty to a film thickness of 1 to 10 mm until the distortion of the structure can be corrected with a spatula, and the smoothness is further improved. Paper / sander polishing is performed to produce

On this putty coating film, for example, a two-pack type urethane primer surfacer is applied to a thickness of 40 μ or more, and then a vehicular top coating is usually applied to a thickness of 40 μ or more.

[0006] As the top coating, a phthalate resin and an acrylic resin are usually used as the base paint, but a two-component urethane excellent in appearance, water resistance, chemical resistance, stain resistance, impact resistance and the like. Recently, attention has been paid to resin-based paints, and they are shifting to urethane resin paints. However, phthalate resin-based paints and fluororesin-based paints are also used depending on the vehicle.

The outer surface of the railcar is sometimes repainted (renewal coating), and the coating process at that time is substantially the same as the above.

In the partial repainting (repair coating) that is regularly carried out, the steel plate is polished by grinder polishing mainly on the damaged part, and then a quick-drying one-component primer is applied, and then the above-mentioned putty is applied. The painting process from the application to the top coating is carried out.

However, the putty conventionally used is
Polyester putty obtained by adding an extender pigment, an accelerator, a stabilizer, etc. to an unsaturated polyester resin varnish and a poly putty having an organic peroxide such as cyclohexanone peroxide as a curing agent are the mainstream and are cured. In this case, a putty coating film that is hard and brittle is provided, so cracks easily occur due to vibration and shock when the vehicle is traveling at high speeds, and the adhesion is not very good, so it may fall off due to rainwater intrusion. Has been pointed out.

As a putty having relatively good crack resistance and adhesion, a sheet metal putty using a combination of an unsaturated polyester resin putty and a benzoyl peroxide curing agent is known in the field of automobile repair and the like. Is extremely inferior in polishing workability and cannot be used for rail car skins.

Further, as already mentioned, in the coating of the outer skins of railway vehicles, especially when newly or completely repainting, the putty is usually applied with a metal spatula having a length of 40 to 60 cm until the distortion of the structure can be corrected 4 to 6 times. Since the putty work is carried out by human power and a large amount of putty is required for each vehicle, weight reduction is one of the important issues especially for high-speed vehicles, and it is excellent in workability and thick coating. There is also a demand for a putty material that can be processed and has a small specific gravity.

[0012]

[Problems to be Solved by the Invention] Therefore, a lightweight putty material having good crack resistance and adhesion, excellent durability, and good polishing workability was found, and it was found that a new putty of a rail car outer plate and repainting. It is an object of the present invention to establish a coating method that is useful even during repair.

[0013]

According to the present invention, the above-mentioned object of the invention is a coating method for sequentially forming a primer coating film, a putty coating film, a primer surfacer coating film and a top coating film on a rail car skin. And a mixed composition of benzoyl peroxide and cyclohexanone peroxide, wherein the putty coating film is an unsaturated polyester resin putty containing 0.1 to 8.0% by weight of minute hollow spheres having an average particle size of 10 to 100 μm. A coating method for a railroad vehicle outer panel, which is a putty coating film having a tensile strength (kg / cm ² ) of 70 to 200 and an elongation rate (%) of 2.0 to 6.0, which is obtained by a combination of curing agents of Achieved by.

In the present invention, the same coating method as in the prior art in which a primer coating film, a putty coating film, a primer surfacer coating film, and an overcoat coating film are sequentially formed on the outer surface of a railroad vehicle is carried out, and a putty coating material is specified. It does not include any special process other than changing to one.

Therefore, as the primer applied to the blasted vehicle outer panel, for example, a paint prepared by mixing an epoxy resin varnish with a color pigment, a rust preventive pigment, an extender pigment, a solvent and the like and a modified aliphatic polyamine-based curing agent are used. It may be a two-pack type epoxy resin primer or a one-pack type epoxy resin primer, and the primer surfacer applied to the surface of the putty that has been subjected to the polishing treatment is, for example, a paint in which a pigment, an additive, a pigment and a solvent are mixed with a polyester resin varnish. When,
2 combined with polyisocyanate varnish as curing agent
It may be a liquid urethane primer surfacer,
Furthermore, the top coat paint may be an acrylic resin type, a two-component urethane resin type, a phthalic acid resin type, or a fluorine resin type paint.

However, the present invention provides a coating method which is completely different from the conventional method in that the putty material for obtaining the putty coating film is a specific one different from the conventional one. is there.

Commercially available polyester putty is divided into two types: a sheet putty in which an unsaturated polyester resin varnish is mixed with an extender pigment, an accelerator, a stabilizer and the like, which is cured with benzoyl peroxide, and a poly putty which is cured with cyclohexanone peroxide. being classified. It is said that this inner sheet metal putty has good thick film properties and good crack resistance and adhesion, but its surface dryness is poor, and polishing with a special tool, Suform, is required. However, since the workability of polishing is extremely poor, it cannot be used for the coating of the outer panel of the rolling stock having a large putty area in terms of work efficiency.

Therefore, poly putty using cyclohexanone peroxide as a curing agent has been mainly used. However, this product has problems in adhesion and crack resistance even if it has good workability in polishing, and it is particularly suitable for high-speed railway vehicles. In such a case, problems such as falling off of the putty coating film have occurred as described above.

Therefore, the present inventor uses a sheet metal putty having good thick film properties such as crack resistance and a mixture composition of benzoyl peroxide and cyclohexanone peroxide as a curing agent in combination to improve the surface dryness of the putty. We have improved and succeeded in providing putty material that can be applied to the coating of rail car skins with a large putty area.

However, when a sheet metal putty having excellent thick film properties is cured with the above-mentioned mixed curing agent, the surface of the putty is hard and the polishing operation itself tends to be extremely difficult. Therefore, in order to improve the workability and to reduce the weight of the putty, in the present invention, 0.1 to 8.0% by weight of the above putty is added with hollow microspheres (microballoons) having an average particle size of 10 to 100 μ. It is included.

The microballoons may be plastic balloons, glass balloons, fly ash balloons, shirasu balloons, etc., but their average particle size must be within the range of 10 to 100 μm. If it is less than 10μ, the polishing workability cannot be improved,
On the other hand, if it exceeds 100 μ, the surface of the putty becomes rough and the finished appearance after the top coating is deteriorated. The amount of microballoons added is selected within the range of 0.1 to 8.0% by weight based on the weight of the putty. If it is less than 0.1% by weight, the effect of improving polishing workability cannot be obtained, while on the other hand, it is 8.0% by weight.
If it exceeds the range, the workability of putting the putty on the spatula tends to decrease. A particularly preferred microballoon is a plastic balloon.

When cured, the putty material of the present invention has a tensile strength of 70 to 200 kg / cm ² and an elongation of 2.0 to 2.0.
It should be able to give a coating of 6.0%. This varies depending on the type of unsaturated polyester resin used as sheet metal putty and the mixing ratio and amount of organic peroxide used as a curing agent, but it is a putty excellent in crack resistance, adhesion, and polishing properties, which is the object of the present invention. In order to obtain a coating film, the putty material must be selected so that the tensile strength and the elongation rate are within the above ranges.

The tensile strength of the cured putty coating film is 70 kg / cm ^2.
If it is less than 200, the crack resistance is deteriorated, and it is 200 kg / c.
If it exceeds m ² , it is not preferable because it is too hard and polishing workability is deteriorated. It is also confirmed that when the elongation rate is less than 2.0%, the crack resistance is deteriorated, and when it exceeds 6.0%, there is paper scumming and the polishing workability is deteriorated.

By using the above putty material, putting it with a spatula until the distortion of the structure can be corrected, and carrying out ordinary paper / sander polishing on the day after curing, durability and adhesion are extremely easy and reliable. It is possible to obtain a very smooth putty coating film, and for example, the addition of 3% microballoons can reduce the putty weight by about 15%. Are achieved at the same time.

The above is the case of new construction of railroad cars and repainting of the entire surface, but the present invention is also applicable to partial repainting of repairs, etc., after the repaired parts are grinder-polished until they reach the substrate such as a steel plate, they are dried. It is sufficient to apply a good one-component primer or two-component primer, then apply the above putty material, and after polishing, apply a primer surfacer and top coat. If desired, it is possible to omit the primer surfacer and apply the acrylic resin overcoat.

The coating method of the present invention is particularly useful as a coating method for outer panels of railway vehicles and railroad vehicles running at high speeds, and is excellent in workability and effectively prevents the coating film from falling off due to vibration, impact, etc. It is possible to obtain a coating film with a beautiful appearance and a beautiful appearance, which is an extremely useful invention in industry.

The present invention will be described below with reference to examples.

[0028]

EXAMPLES In the following examples, the following primers,
A putty, urethane primer surfacer, and a two-part polyurethane resin top coat were used.

[0029] Paint liquid / hardener / thinner = 4/1 / 0.4 (weight ratio)
Mix with and use by air spray Paint to a film thickness of 40μ, dry for 1 day (2) Commercial poly putty nax poly putty acty (manufactured by Nippon Paint Co.) Unsaturated polyester resin varnish 39.0 parts (NV 66%, acid value 30 or less) Constitution Pigment (talc) 59.0 Accelerator (cobalt naphthenate and amines) 1.7 Stabilizer (hydroquinones) 0.3 Total 100.0 Curing agent for poly putty nax poly putty hardener yellow (Nippon Paint Co., Ltd.) Cyclohexanone par Oxide 88.0 parts Plasticizer 9.0 Pigment 3.0 Total 100.0 The putty and the curing agent are mixed in a weight ratio of 100/2 before use, putty is applied using a spacer, dried for one day, and optionally sanded with a paper / sander. Mix paint solution, curing agent and thinner in a weight ratio of 5/1/1, apply 40μ with air spray and dry for 1 day. Mix paint solution, curing agent and thinner in a weight ratio of 4/1/1 and apply 40μ with air spray to dry for 1 day.

[0030]

Example 1 Polypropylene plate (300 × 150 ×
2.0 mm), a spacer with a thickness of 1.0 mm is placed at both ends, and the following four types of putty are putted with a plastic spatula. Commercial poly putty, nax poly putty Acty (manufactured by Nippon Paint Co., Ltd.) / Nax poly putty Hardener Yellow (manufactured by Nippon Paint Co., cyclohexanone peroxide) Mixing ratio 100/2 Putty formulation example A /
Curing agent formulation example C in which the mixing ratio of benzoyl peroxide and cyclohexanone peroxide is 3 to 7 C Putty formulation example A / Curing agent formulation example D in which the mixing ratio of benzoyl peroxide and cyclohexanone peroxide is 5 to 5
Putty formulation example A / Curing agent formulation example E in which the mixing ratio of benzoyl peroxide and cyclohexanone peroxide is 7: 3 is put on each putty, and after curing, peeling is performed.
The sheet-like putty is cut into 10 mm × 50 mm with a cutter knife to obtain a test piece. Next, using a tensile tester Tensilon (manufactured by Toyo Baldwin Co., Ltd.), tensile strength (kg / cm ² ) elongation (%) at a tensile speed of 5 mm / min.
Is measured.

[0031]

[Example 2] Polished steel sheet JIS G 3141 (SPCC-
SB) (150 × 70 × 0.8 mm) is degreased. As a degreasing agent, flash point -6 ° C, ignition point 250 ° C, specific gravity 0.73
Nax silicon off (manufactured by Nippon Paint Co., Ltd.) consisting of a colorless petroleum solvent at / 20 ° C. was used. Then, it is ground with a No. 60 paper / disk sander. Next, degreasing is performed with a degreasing agent composed of the above petroleum solvent. Apply a 2-pack type epoxy resin primer by air spray coating at 40μ. After drying at room temperature for 16 hours, spacers having a thickness of 2.0 mm are placed on both ends of the test plate and putted with the four types of putty described in Example 1. After leaving it for 16 hours at room temperature, the bending tester shown in FIG. 1 was used to move the test plate with the putty side down at a constant speed (0.63 mm).
/ Sec) and measure the distance that the push rod descends when the putty cracks with a dial gauge.

[0032]

Example 3 Putty was put on in the same manner as in Example 2, and two types of putty were put on the market, nax poly putty Acty / n.
ax poly putty Hardener Yellow (manufactured by Nippon Paint Co., Ltd.) Putty formulation example A / Curing agent formulation example D After drying at room temperature for 16 hours, a urethane primer surfacer is coated with 40 μm by air spray coating. After drying at room temperature for 16 hours, a urethane resin top coat of 40 μm is applied by air spray.
After 7 days at room temperature, an accelerated weather resistance test (testing time: 1000 hours) was carried out using a sunshine weather ometer. Then, using a bending tester as in Example 2, the test plate with the putty surface facing down was bent at a constant speed (0.63 mm / sec), and the distance of the push rod at the time of cracking of the coating film was dialed. Measure with a gauge.

[0033]

[Example 4] Polished steel plate JIS G 3141 (SPCC-
SB) (150 × 70 × 0.8 mm) is degreased. As a degreasing agent, flash point -6 ° C, ignition point 250 ° C, specific gravity 0.73
Nax silicon off (manufactured by Nippon Paint Co., Ltd.) consisting of a colorless petroleum solvent at / 20 ° C. was used. Then, it is ground with a No. 60 paper / disk sander. Next, degreasing is performed with a degreasing agent composed of the above petroleum solvent. Next, a two-pack type epoxy resin primer is applied by 40 μm by air spray coating. 16
After drying at room temperature for 2 hours, place 0.8mm thick spacers on both ends of the test plate and put two types of putty commercially available poly putty na.
x Polypaty Acty (manufactured by Nippon Paint Co., Ltd.) / nax Polypati Hardener Yellow (manufactured by Nippon Paint Co., Ltd., cyclohexanone peroxide) Mixing ratio, 100/2 parts by weight Putty compounding example A / Curing agent compounding example D (benzoyl peroxide / cyclohexanone peroxide) Mixed composition) Putting putty in a mixing ratio of 100/2 parts by weight. 1
After drying at room temperature for 6 hours, it is immersed in warm water at 60 ° C. for 3 hours and then taken out. After left at room temperature for 1 hour, the test plate is bent at 90 degrees and the adhesion state is evaluated.

[0034]

[Example 5] Polished steel sheet JIS G 3141 (SPCC-
SB) (300 × 400 × 0.8 mm) is degreased. As the degreasing agent, nax silicon off (manufactured by Nippon Paint Co., Ltd.) was used. Then, it is ground with a No. 60 paper / disk sander. Next, degreasing is performed with the above degreasing agent. Put two kinds of the following three kinds of putty with a plastic spatula, each having a thickness of 2 to 3 mm. Putty formulation example B / Stainless steel putty curing agent (benzoyl peroxide) Putty formulation example B / Curing agent formulation example D
(Benzoyl peroxide / cyclohexanone peroxide) Putty formulation example A / Curing agent formulation example D (benzoyl peroxide / cyclohexanone peroxide) Polishing workability was 10 after 6 hours and 16 hours at room temperature.
Polish and evaluate with No. 0 paper / disk sander. Surface dryness is 100th paper /
Polish with a disc sander and evaluate the degree of parchment on paper.

[0035]

[Example 6] According to JIS K 5400 paint general test method 4, 6, 2 specific gravity cup method, the specific gravity of the putty is measured to evaluate the weight of the putty. The putty tested was a commercial poly putty, n
ax poly putty acty (manufactured by Nippon Paint Co., Ltd.) / nax
Polypate Hardener Yellow (Nippon Paint Co., Ltd., cyclohexanone peroxide) mixing ratio 100/2
Putty formulation example A / Curing agent formulation example D (mixture of benzoyl peroxide and cyclohexanone peroxide).

[0036]

【result】

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Brief description of the drawings]

FIG. 1 attached is a cross section of a bending tester for testing crack resistance of a coating film obtained by the method of the present invention. 1 is a dial gauge, 2 is a test plate.

FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Okamura 19-17 Ikedanaka-cho, Neyagawa City, Osaka Japan Paint Co., Ltd.

Claims (1)

(57) [Claims] 1. A coating method for sequentially forming a primer coating film, a putty coating film, a primer surfacer coating film, and a top coating film on a rail vehicle outer plate, wherein the putty coating film is an average particle size of an unsaturated polyester resin putty. Tensile strength (kg / cm ²⁾ obtained by the combination of putty containing 0.1 to 8.0% by weight of micro hollow spheres having a diameter of 10 to 100 μm and a curing agent composed of a mixed composition of benzoyl peroxide and cyclohexanone peroxide. ) 70-200, elongation rate (%) 2.0-6.0 putty coating film, The coating method of the rail vehicle outer panel characterized by the above-mentioned.