JP2023131776A - Insulation film formation method, metallic structure, and coating material for insulation film formation - Google Patents

Abstract

To provide an insulation film formation method, a metallic structure, and a coating material for insulation film formation.SOLUTION: An insulation film formation method 2 includes: a primer coating step S10 of coating a primer onto an object TG, and forming a primer coating film PM; a primer drying step S20 of drying the primer coating film PM; a coating step S30 for insulation film formation for coating a coating material for insulation film formation onto the object TG, and forming an insulation film; and an insulation film drying step S40 of drying the insulation film. The coating step S30 for insulation film formation coats the coating material for insulation film formation onto the primer coating film PM. The insulation coating film PR preferably has light transmissivity in a cured and dried state. This is because the surface state of the object TG can be visually observed, after formation of the insulation coating film PR.SELECTED DRAWING: Figure 2

Description

There is an application for exception to loss of novelty.

The present invention relates to a method for forming an insulating film, a metal structure provided therein, and a coating material for forming an insulating film.

When a railway track rail (hereinafter simply referred to as a rail) is directly fastened to a wooden sleeper, the rail is inelastically fastened to the wooden sleeper that is the substrate. Therefore, when a vertical or lateral external force is applied to the rail due to expansion and contraction due to temperature or vibration due to train load, the dog nails tend to loosen or pull up. Therefore, in order to maintain the holding force of the rail even when such an external force is applied, for example, a rail fastening device is used to connect the rail R to a concrete track bed (hereinafter simply referred to as concrete track), which is a so-called slab track. A method of elastically supporting the roadbed (referred to as a trackbed) 3 has been adopted (for example, Patent Document 1).

Utility Model Publication No. 5-7704

By the way, when the rail was actually used, an event occurred in which the rail broke over time. As a result of extensive research, it was determined that rail breakage was caused by electrolytic corrosion caused by a portion of the current flowing through the rails leaking into the ground. However, since the portion of the rail that comes into contact with the ground is the portion that comes into contact with the rail fastening device or the sleeper, it is not possible to provide a thick insulating member.

In view of the above problems, the present invention provides a method for forming an insulating film, a metal structure provided with the same, and a paint for forming an insulating film.

The present invention is an insulating film forming method for forming an insulating film on a target object, wherein the insulating film has a thickness of 1 mm or less, and the insulating film forming method comprises applying an insulating film forming paint to the target object. a coating step, and an insulating film drying step of drying the coating film of the insulating film forming paint, the insulating film forming paint including a base agent containing an isocyanate component and a curing agent containing an amine compound. The present invention is a paint for forming polyurea, and is characterized in that the paint for forming an insulating film has a dry time to the touch of 30 minutes or more.

The metal structure of the present invention includes a metal object and an insulating film formed on the object, and the insulating film is made of polyurea resin and has a thickness of 1 mm or less.

The present invention is an insulating film-forming paint for forming an insulating film, and is a polyurea-forming paint containing a main agent containing an isocyanate component and a curing agent containing an amine compound, and has a dry time to the touch of 30 minutes. It is characterized by the above.

According to the present invention, since a thin insulating film can be provided on a metal structure such as a rail, leakage current that may cause breakage or the like can be prevented.

It is a flow chart showing an outline of a first construction method. FIG. 2 is an explanatory diagram showing an outline of an insulating film. It is a side view showing an outline of a rail unit for trains. It is a side view showing an outline of a rail. It is a flow chart showing an outline of a second construction method.

As shown in FIGS. 1 and 2, the insulating film forming method 2 includes a primer application step S10 in which a primer is applied to the object TG to form a primer coating PM, and a primer drying step in which the primer coating PM is dried. S20, an insulating film forming coating step S30 in which an insulating film forming paint is applied to the object TG to form an insulating film, and an insulating film drying step S40 in which the insulating film is dried.

The target object TG is a metal structure, and includes, for example, wiring through which current flows, electrodes, train rails, and the like.

In the primer application step S10, a primer is applied directly or indirectly to the target object TG. As a method for applying the primer, a known method such as a roller or a brush can be used. Depending on the application conditions, a roller with short bristles, a sponge roller, etc. may be used.

The primer coating PM preferably has translucency in the cured and dry state. This is because the surface state of the target object TG can be visually observed after the primer coating PM is formed.

Here, curing and drying means that when the center of the painted surface is strongly pinched between the thumb and forefinger, no dents are left on the painted surface due to fingerprints, and no movement of the paint film is felt. This refers to the condition in which no scratch marks are left on the painted surface by rapid repeated rubbing (JIS K 5600-1-1: 1999).

The primer may be of any type as long as it has high adhesion to the object TG, and any known material such as vinyl synthetic resin may be used.

In the primer drying step S20, the primer coating PM formed in the primer coating step S10 is dried. As for the drying method, the object may be left standing in the atmosphere. Although the drying time may be set appropriately depending on the purpose, for example, it is preferable to carry out the drying for 30 minutes or more, and it is more preferable to carry out the drying for 1 hour or more.

The thickness of the cured and dried primer coating PM may be appropriately set depending on the purpose, but for example, it is preferably 20 μm or more and 60 μm or less, and more preferably 30 μm or more and 50 μm or less.

In the insulating film forming coating step S30, an insulating film forming paint is applied to the primer coating PM. It is preferable that the insulating coating film PR has translucency when cured and dried. This is because the surface state of the target object TG can be visually observed after the insulating coating film PR is formed.

As a method for applying the paint for forming an insulating film, a known method such as a roller or a brush can be used. Depending on the application conditions, a roller with short bristles, a sponge roller, etc. may be used.

The coating for forming an insulating film is a coating for forming polyurea, and includes a main agent containing an isocyanate component and a curing agent containing an amine compound.

The proportion of the main ingredient is preferably 50% by weight or more and 70% by weight or less, more preferably 55% by weight or more and 65% by weight or less, based on the total weight.

The proportion of the curing agent is preferably 20% by weight or more and 40% by weight or less, more preferably 25% by weight or more and 35% by weight or less, based on the total weight.

Further, the lower limit of the ratio of the main ingredient contained in the insulating film forming paint to the curing agent contained in the insulating film forming paint is preferably 1.3 times or more, more preferably 1.5 times or more. , is particularly preferably at least twice as large. The upper limit of this ratio may be set depending on the application, but for example, it is preferably 4 times or less, and preferably 3 times or less.

Note that the coating material for forming an insulating film may contain additives depending on the purpose. Examples of additives include formaldehyde and acetic acid. The proportion of the additive may be appropriately set depending on the purpose, and is preferably 3% by weight or more and 15% by weight or less, more preferably 5% by weight or more and 10% by weight or less.

The drying time of the paint for forming an insulating film to the touch is preferably 30 minutes or more, more preferably 60 minutes or more, and particularly preferably 120 minutes or more.

The dry-to-touch time refers to the time from the start of application until the paint film becomes dry to the touch. Dry to the touch refers to the condition in which your fingertips do not become dirty when you lightly touch the center of the painted surface with your fingertips (JIS K 5600-1-1: 1999).

This makes it easy for the coating film to spread to a uniform thickness, making it possible to form a thin coating film with a uniform thickness on a long structure. Further, since the insulating film forming paint is a one-component type, there is no need to adjust the ratio at the work site, and as a result, variations in the quality of the insulating film can be suppressed.

In the insulating film drying step S40, the insulating coating film PR of the insulating film forming paint is dried. As for the drying method, the object may be left standing in the atmosphere. Although the drying time may be set appropriately depending on the purpose, for example, it is preferable to carry out the drying for 30 minutes or more, and it is more preferable to carry out the drying for 1 hour or more.

The thickness of the cured and dried insulating coating PR may be appropriately set depending on the purpose, and is, for example, 1 mm or less. Further, the thickness of the insulating coating film PR is preferably 100 μm or more and 800 μm or less, more preferably 150 μm or more and 600 μm or less, particularly preferably 200 μm or more and 500 μm or less.

In this way, an insulating coating film 90 in which the primer coating PM and the insulating coating PR are laminated is formed on the object TG.

Note that for the existing rail, a cleaning process performed before the coating process for forming an insulating film, and a degreasing process performed between the cleaning process and the coating process for forming an insulating film may be performed. In the keren process, the surface of the object to be coated is prepared before applying the paint. Specifically, deposits such as rust, black coating, salt, moisture, dust, and dirt are removed from the object. Furthermore, in the cleaning process, the surface to be coated may be made uneven in order to improve the adhesion of the paint. In the degreasing process, the coated surface is degreased after the cleaning process.

Further, when performing the primer application step S10 or the insulating film forming application step S30 on an existing rail, it is preferable to perform each step on the rail with the surface to be coated facing downward.

Next, a procedure for forming an insulating film on a rail (object) will be explained.

As shown in FIGS. 3 and 4, the train rail unit 100 includes sleepers 110, rails 120, and a fixing structure 130 that fixes the rails 120.

The sleepers 110 are for supporting the rails 120, and are provided on the ground, gravel, concrete, or the like. The sleeper 110 is made of an insulating material such as wood, concrete, or plastic. When the rail 120 is installed at the center of the sleeper 110 in the longitudinal direction (horizontal direction in the drawing), sleeper side bolt holes 110X are opened in the sleepers 110 on both sides of the train rail 12. The sleeper side bolt hole 110X is formed with an internal thread that can be screwed into a fixing bolt 133 (described later).

The rail 120 is provided on the sleeper 110, and includes a plate-shaped mounting portion 120A that contacts the sleeper 110, an extending portion 120B extending upward from the mounting portion 120A, and a top end of the extending portion 120B. A columnar rolling portion 120C on which the provided wheels roll is provided. The rail 120 is arranged to intersect the sleeper 110 at a right angle or at a predetermined angle. The dimensions of the rail 120 may be set appropriately depending on the purpose, but for example, the width of the mounting portion 120A is 100 m or more and 300 m or less, the width of the rolling portion 120C is 50 mm or more and 100 mm or less, and the length is The length is 15 m or more and 50 m or less.

The fixing structure 130 fixes the rail 120 to the sleeper 110, and includes a positioning member 131 fixed to the sleeper 110, a leaf spring structure 132 provided extending from the positioning member 131 toward the mounting portion 120A, and a plate A fixing bolt 133 is provided to fix the spring structure 132 to the sleeper.

The positioning member 131 is locked in an engagement groove 110M formed in the sleeper 110. The engagement groove 110M is located outside the sleeper side bolt hole 110X.

The leaf spring structure 132 includes a restraining part 132A and a leaf spring part 132B located above the restraining part 132A. The base end of the restraining part 132A is integrated with the positioning member 131, and the distal end of the restraining part 132A can be engaged with the mounting part 120A. The base end of the leaf spring part 132B is integrated with the positioning member 131, and spring-side bolt holes 132AX and 132BX are formed at the tips of the restraining part 132A and the leaf spring part 132B, respectively.

After inserting the fixing bolt 133 into the spring side bolt hole 132BX and the spring side bolt hole 132AX in this order, the fixing bolt 133 is screwed into the sleeper side bolt hole 110X. In this way, the fixing structure 130 can fix the rail 120 to the sleeper 110.

The insulating film 180 (insulating coating film) is preferably provided on the mounting portion 120A. The electrical resistivity of the insulating film 180 is preferably 1×10 ⁸ or more, more preferably 1×10 ¹³ or more, and particularly preferably 1×10 ¹⁵ or more.

It is preferable that the insulating film 180 is provided on the mounting portion 120A and the extension portion 120B. The insulating film 180 may be provided on the entire extended portion 120B, or may be provided on a portion (for example, the lower portion) of the extended portion 120B. For example, the lower portion of the extending portion 120B is preferably a portion that is 50% or less of the total height of the extending portion 120B.

Since the insulating film 180 is thin and has sufficient insulation, it can maintain insulation between the rail 120 and members around it. Therefore, leakage current that may cause breakage of the rail 120 can be prevented.

Note that, as shown in FIGS. 5 and 6, the insulating film forming method 2 may include an overcoating step S50 and an overall drying step S60.

In the overcoating step S50, which is performed after the insulating film drying step S40, an insulating film forming paint is applied to the insulating coating PR. Here, the recoating step S50 is preferably performed on the insulating coating PR that is dry to the touch.

The overall drying step S60 is performed after the overcoating step S50, and it is preferable to dry the insulating coating PR formed in the insulating film forming coating step S30 and the overcoating step S50.

(Experiment 1)
Insulating film formation method 2 was applied to the sample to form an insulating coating film 90 in which a primer coating PM and an insulating coating PR were laminated on the sample surface. The insulating film drying step S40 and the primer drying step S20 were each performed for 1 hour. The thickness of the primer coating PM in the cured state was 0.04 mm, and the thickness of the insulating coating PR in the cured state was 0.5 mm.

(Primer)
The composition of the primer used in Experiment 1 is as follows.
Vinyl resin 45% by weight
Toluene (CAS No. 108-88-3) 33% by weight
Xylene (CAS No. 1330-20-7) 7% by weight
Isobutyl acetate (CAS No.110-19-0) 5% by weight
Propylene glycol (CAS No.108-65-6) 4% by weight
Methyl isobutyl ketone (CAS No.108-10-1) 6% by weight

(Paint for forming an insulating film)
The composition of the insulating film forming paint used in Experiment 1 is as follows.
Modified amine curing agent 30% by weight
Dicyclohexylmethane diisocyanate 60% by weight
Additives (formaldehyde, acetic acid) 10% by weight or less

(Experiment 2)
Insulating film forming method 2 was conducted under the same conditions as Experiment 1, except that an insulating coating film 90 consisting of only an insulating coating PR was directly formed on the sample surface.

(Evaluation method)
The surface resistivity of the obtained insulating coating film 90 was measured.
The surface resistivity was measured as follows.
Test standard JIS K6911:1995
Test equipment Digital ultra-high resistance/micro current meter 8340A type (manufactured by ADC Co., Ltd.) Main electrode 50mmφ/Guard electrode Inner diameter 70mmφ/Outer diameter 80mmφ
Applied voltage 500V
Application time 60 seconds Test environment 23±2℃/50±5%RH
Number of exams: 3
Measurement surface Glossy surface Condition adjustment 23±2℃/50±5%RH, 90 hours or more Electrode treatment Conductive rubber Test piece shape Approx. 100mm x Approx. 100mm

(Evaluation results)
Experiment 1
Surface resistance 2.1×10 ¹⁴ Ω
Surface resistivity 4.0×10 ¹⁵ Ω/sq
Experiment 2
Surface resistance 9.3×10 ¹³ Ω
Surface resistivity 1.7×10 ¹⁵ Ω/sq
Note that the surface resistance and surface resistivity are the average of the measured values of three samples.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that various changes can be made without departing from the gist of the present invention.

2 Insulating film forming method 90 Insulating coating film 100 Train rail unit 110 Sleeper 120 Train rail 120A Placement part 120B Extension part 120C Rolling part 130 Fixed structure 131 Member 132 Leaf spring structure 180 Insulating film S10 Primer application step S20 Primer drying process S30 Insulating film forming coating process S40 Insulating film drying process S50 Coating process S60 Overall drying process TG Target object

The present invention relates to a method for forming an insulating film , a metal structure, and a coating material for forming an insulating film.

In view of the above problems, the present invention provides an insulating film forming method , a metal structure, and an insulating film forming paint.

Claims (11)

An insulating film forming method for forming an insulating film on a target object,
The insulating film has a thickness of 1 mm or less,
an insulating film forming coating step of applying an insulating film forming paint to the object;
an insulating film drying step of drying the coating film of the insulating film forming paint,
The coating for forming an insulating film is
A main agent containing an isocyanate component,
A curing agent containing an amine compound;
A method for forming an insulating film, characterized in that the paint for forming an insulating film takes a touch drying time of 30 minutes or more. an overcoating step performed after the insulating film drying step, in which the insulating film forming paint is applied to the coating film of the insulating film forming paint;
an overall drying step that is carried out after the overcoating step and which dries the coating film formed by the insulating film forming coating step and the overcoating step;
In the insulating film drying step, the coating film of the insulating film forming paint is dried to the touch,
2. The insulating film forming method according to claim 1, wherein in the overcoating step, the insulating film forming paint is applied to the paint film that is dry to the touch. a primer application step of applying a primer to the object;
a primer drying step of drying the primer coating film formed by the primer coating step,
3. The insulating film forming method according to claim 1, wherein in the insulating film coating step, the insulating film forming paint is applied to the primer coating film. 4. The method of forming an insulating film according to claim 1, wherein the object is a conductive rail. a smearing process performed before the coating process for forming an insulating film;
a degreasing step performed between the cleaning step and the insulating film forming coating step;
The method for forming an insulating film according to any one of claims 1 to 4, comprising the following. a metal object,
an insulating film formed on the object,
A metal structure, wherein the insulating film is made of polyurea resin and has a thickness of 1 mm or less. The object is a rail,
The rail includes a mounting section that is mounted on the railroad ties in use;
an extension part extending upward from the mounting part;
When defined as having a rolling part provided in the extension part and on which the wheels roll,
7. The metal structure according to claim 6, wherein the insulating film is formed at least on the mounting portion. 8. The metal structure according to claim 6, wherein the insulating film is formed on the mounting portion and the extending portion. It is an insulating film forming paint for forming an insulating film,
A main agent containing an isocyanate component,
A curing agent containing an amine compound;
A paint for forming an insulating film, characterized in that it takes 30 minutes or more to dry to the touch. Contains additional additives,
The paint for forming an insulating film according to claim 9, wherein the additive contains at least one of formaldehyde and acetic acid. The isocyanate component is 62% by weight or less,
The coating material for forming an insulating film according to claim 9 or 10, wherein the content of the amine compound is 32% by weight or less.

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