KR101446691B1 - Constructing method for noise and vibration prevention of vehicle floor - Google Patents

Abstract

The present invention relates to a construction method for blocking noise and vibration at the bottom of a transportation means, and a method of coating a water-soluble urethane-based coating material on a bottom of a welding portion or a transportation means having a plurality of unevenness to form a flat sheet, It is possible to conceal the surface condition of the floor and minimize the vibration and noise generated when the transportation means is operated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for noise and vibration isolation of a vehicle floor,

TECHNICAL FIELD The present invention relates to a construction method capable of minimizing vibration and noise introduced from the bottom of a vehicle body during operation of a transportation means, and concealing a bottom surface condition of rough transportation means by welding or unevenness.

When the vehicle is traveling on a rail, noise is generated due to the interaction between the vehicle and the rail, and some of the noise energy is transmitted to the vehicle body to cause vibration on the vehicle, It has a bad influence.

Therefore, in order to minimize the noise and vibration generated from the lower part of the underbody of the train to the interior of the vehicle, a floorboard is installed on the underside of the train with a vibration proof rubber and a support board on the upper surface of the body underframe. At this time, the floor of the train should be constructed with sufficient consideration of various conditions to minimize the excellent repellency, durability, noise and vibration.

Conventional methods of constructing the anti-vibration floor for a train can be variously applied, but the methods as shown in FIGS. 1 and 2 are mainly used.

Fig. 1 is a view for explaining a conventional method of installing a dustproof floor for a train, and Fig. 2 is a partial enlarged view of Fig. 1. Fig.

1 and 2, the vibration damping sheet 2 is installed on the upper surface 1 of the vehicle body frame 1, and the anti-vibration rubber 3 and the support 4 are installed in the longitudinal direction or the lattice- do. The space between the anti-vibration rubber 3 is filled with the sound-absorbing and thermal insulating material 5, and then the floor board 6-1 is placed at the position where the vibration-proof rubber 3 is to be installed. Then, the floorboard 6-2 to be joined is placed on the top of the anti-vibration rubber. The connecting steel plate 7 for fitting is inserted into the groove at the end of the floorboard 6-1 in order to increase the connection strength between the floorboard 6-1 and the floorboard 6-2. The groove of the floor board 6-2 to be connected is fitted to the connecting steel plate 7 for fitting and arranged in a place to be installed. After the floorboards have been arranged, a screw hole is formed in the connecting steel plate 8 on the floorboard using a drill and a tap to connect and fix the floorboard 6-1 and the floorboard 6-2, So that the floorboards are firmly fixed. In order to eliminate height difference and gap between the floorboard (6-1) and the floorboard (6-2), the gap filler (10) is filled in the floor joints and the like and polished and flattened. Then, the floorboard 11 is installed on the upper surface of the floorboard to complete the anti-vibration floor.

However, in the above-mentioned conventional method of installing a dustproof floor, all of the structural members must be completely used and each step must be constructed. As a result, the number of construction processes increases, resulting in an increase in the construction time as well as an increase in the cost of materials and labor. The overall assembling workability, workability, and economical efficiency are lowered.

Therefore, a coating material which can easily be applied to form a flat bottom and minimize vibration and noise is demanded instead of the vibration-proof floor which constructs each constituent member in a stepwise manner as described above.

Korean Utility Registration No. 0174991 Korean Patent Publication No. 1999-0073637

SUMMARY OF THE INVENTION It is an object of the present invention to provide a construction method capable of minimizing vibration and noise introduced from the bottom of a vehicle body during operation of a transportation means by concealing the bottom surface condition of rough transportation means by unevenness.

In order to accomplish the above object, the present invention provides a method for blocking noise and vibration in a floor of a transportation means, comprising the step of applying a water-soluble urethane coating material to a floor of a welding portion or a transportation means having a plurality of unevenness to form a flat sheet .

The water-soluble urethane-based coating material may be applied as one kind selected from the group consisting of spraying, brush, rubber spatula and trowel for laying.

The water-soluble urethane coating can be applied once or several times in millimeters from the top of the welded portion or concavity and convexity in an appropriate thickness (h), preferably a thickness h of 1 to 8 mm, more preferably 2 to 4 mm, Lt; / RTI >

When the water-soluble urethane-based paint is applied two to ten times in succession, at least one selected from the group consisting of sound-insulating materials such as steel plates, rubber plates, cement plates and plastic plates May be additionally provided.

The water-soluble urethane-based paint includes a water-soluble polyurethane resin, a plasticizer, an aluminum hydroxide, a barium sulfate, a flame-retarding auxiliary agent, and a solvent; A curing agent comprising a plasticizer, an aromatic isocyanate, and a solvent.

The subject of the present invention is a composition comprising 5 to 25% by weight of a water-soluble polyurethane resin, 10 to 40% by weight of a plasticizer, 20 to 70% by weight of aluminum hydroxide, 5 to 40% by weight of barium sulfate, 1 to 20% ; The curing agent may comprise from 40 to 80% by weight of a plasticizer, from 10 to 50% by weight of an aromatic isocyanate and from 1 to 10% by weight of a solvent.

The subject and the curing agent may be mixed in a weight ratio of 1: 0.1 to 0.8.

Prior to applying the water-soluble urethane-based paint,

Arranging a surface of the vehicle bottom; And forming a primer layer on the bottom of the transportation means.

The transportation means may be one selected from the group consisting of a train (light rail), a train, a passenger car, and a bus.

The method of the present invention for blocking noise and vibration at the bottom of a transportation means can provide a smooth floor by applying a water-soluble urethane coating to the bottom of a transportation means having a plurality of irregularities, and minimize vibration and noise generated during operation. Further, since a seamless floor is formed, control and management of dust, foreign matter, and the like is convenient.

Fig. 1 is a view for explaining a conventional method of installing a dustproof floor for a train.
2 is a partially enlarged view of Fig.
3 is a cross-sectional view illustrating a primer layer and a noise and vibration preventing layer on the bottom of a vehicle according to an embodiment of the present invention.

TECHNICAL FIELD The present invention relates to a construction method for concealing a surface state of a rough floor by a welded portion or unevenness, and minimizing vibration and noise generated when the transportation means is operated.

Hereinafter, the present invention will be described in detail.

The present invention provides a method for constructing a water-soluble urethane-based paint on the floor of a transportation means, which will be described with reference to Fig.

The method of the present invention for blocking noise and vibration at the bottom of a transportation means includes arranging a surface of a transportation means bottom; Forming a primer layer on the bottom of the transportation means; And a step of forming a flat sheet by applying a water-soluble urethane-based coating to a bottom of a welded portion having a height of 1 to 10 mm, preferably 1 to 3 mm, or a transportation means having a plurality of unevennesses.

The transportation means is a means for transporting a person or an object, and is not particularly limited, but may be preferably one selected from the group consisting of a train (light rail), a train, a passenger car and a bus.

First, the surface of the construction surface (the floor of the transportation means 100) is organized. For example, the surface of the construction surface 100 is laid out and the damaged and damaged portions are repaired, the surface is cleaned, and the foreign matter is removed.

Next, a primer layer (200) is formed on the assembled surface (100). The primer layer 200 is a layer for fixing the noise and vibration preventive layer 300 formed by the water-soluble urethane-based paint, and forms a conventional urethane polymer primer layer 200. The urethane polymer is formed by mixing a base and a curing agent . In some cases, the primer layer 200 may be omitted.

Next, a noise and vibration preventing layer 300 is formed on the top surface of the primer layer 200. The noise and vibration preventing layer 300 is formed by coating a water-soluble urethane coating material 1 to 10 times, and is formed so as to be flat (self-leveling) so as to conceal the surface state of a welded portion or bottom of a transportation means provided with the unevenness.

When the water-soluble urethane-based paint is applied two or more times, a sound-insulating material is additionally provided between each layer coated with the water-soluble urethane-based paint, so that noise and vibration can be blocked more effectively. The sound insulating material may include at least one selected from the group consisting of steel sheets, rubber sheets, cement sheets and plastic sheets. The thickness of the sound insulating material is 0.1 to 1 mm, preferably 0.2 to 0.5 mm. When the thickness of the sound insulating material is less than the lower limit, noise and vibration blocking properties can not be exhibited. If the thickness of the sound insulating material is higher than the upper limit, some of the water soluble urethane coating layers existing in multiple layers may be dropped.

The water-soluble urethane-based coating material is preferably formed by mixing a base and a curing agent.

The subject matter may include water soluble polyurethane resins, plasticizers, aluminum hydroxide, barium sulfate, flame retardant adjuvants and solvents.

The water-soluble polyurethane resin improves adhesion to the bottom of the transportation means, and its content is 5 to 25% by weight, preferably 10 to 20% by weight, based on 40% by weight of solids. When the content of the water-soluble polyurethane resin is less than the lower limit, adhesion between the paint and the floor or primer layer of the transportation means may be deteriorated and may not be formed smoothly. If the content exceeds the upper limit, The vibration of the transportation means and the noise of the transportation means can be directly transmitted to the person or the object.

The plasticizer improves flexibility, elasticity, adhesiveness, processability and the like, and specifically includes at least one selected from the group consisting of polyester polyol, polyether polyol, butyl acrylate and vinyl isobutyl ether.

The content of the plasticizer is 10 to 40% by weight, preferably 20 to 30% by weight. When the content of the plasticizer is lower than the lower limit, the paint is cured and the elasticity of the formed barrier layer 300 is lowered, so that the vibration and noise of the transportation means can be directly transmitted to the person or the object and the adhesiveness may be lowered. The strength is lowered, and a part of the barrier layer 300, especially the portion coated on the concavo-convex portion, may be dropped even in a weak impact.

The aluminum hydroxide is an anionic compound and has the characteristics of emitting anions and far-infrared rays, improving durability, water resistance, surface hardness and enabling self-leveling of the coating, and the average particle diameter of aluminum hydroxide may be 100 nm to 2 탆. If the average particle diameter of the aluminum hydroxide is less than the lower limit value, the above characteristics may not be satisfied. If the average particle diameter exceeds the upper limit value, the paint may not be applied and the surface of the barrier layer 300 may not be smooth.

The content of aluminum hydroxide is 20 to 70% by weight, preferably 30 to 60% by weight. If the content of aluminum hydroxide is less than the lower limit value, the above properties may not be satisfied. If the content is above the upper limit value, elasticity and adhesiveness may be lowered.

The barium sulfate improves the gloss of the surface of the barrier layer 300 and improves durability, water resistance and surface hardness. The average particle diameter of barium sulfate may be 100 nm to 2 탆. If the average particle diameter of barium sulfate is less than the lower limit value, the above characteristics may not be satisfied. If the average particle diameter exceeds the upper limit value, the paint may not be applied and the surface of the prevention layer 300 may not be smooth.

The content of barium sulfate is 5 to 40% by weight, preferably 10 to 25% by weight. If the content of barium sulfate is less than the lower limit, the above properties may not be satisfied. If the content is above the upper limit, elasticity and adhesiveness may be lowered.

The flame-retardant adjuvant may be a fine particulate antimony trioxide having an average particle size of 0.3 to 0.4 mu m to enhance flame retardancy. When the average particle diameter of the flame-retardant aid is less than the lower limit value, flame retardancy may not be expected. If the average particle diameter exceeds the upper limit, the paint may not be applied and the surface may not be smooth.

The content of the flame retardant aid is 1 to 20% by weight, preferably 5 to 10% by weight. If the content of the flame-retardant aid is less than the lower limit, flame retardancy may not be expected. If the content is above the upper limit, elasticity and adhesiveness may be deteriorated.

Examples of the solvent include at least one selected from the group consisting of xylene, n-butanol, cyclohexanol, cellosolve acetate, and toluene.

The content of the solvent is 1 to 10% by weight, preferably 3 to 8% by weight, in consideration of the overall physical properties of the coating film. When the content of the solvent is less than the lower limit, a crack may be generated in the curing-preventing layer 300. If the content of the solvent is higher than the upper limit, the hardness and adhesiveness of the preventing layer 300 may be lowered.

In addition, the curing agent may include a plasticizer, an aromatic isocyanate, and a solvent.

Examples of the plasticizer include at least one selected from the group consisting of polyester polyols, polyether polyols, butyl acrylate, and vinyl isobutyl ether.

The content of the plasticizer is 40 to 80% by weight, preferably 50 to 60% by weight. When the content of the plasticizer is lower than the lower limit, the paint is cured and the elasticity of the formed barrier layer 300 is lowered, so that the vibration and noise of the transportation means can be directly transmitted to the person or the object and the adhesiveness may be lowered. The strength is lowered, and a part of the barrier layer 300 may be dropped even in a weak impact.

The aromatic isocyanate reacts with the water-soluble polyurethane resin of the subject to cure, and is excellent in resistance to yellowing and light fastness, and exhibits fast drying and curing rate at low temperatures. Specific examples of the aromatic isocyanates include 2,4 / 2.6-toluene diisocyanate (TDI 80/20), 2,4-toluene diisocyanate (TDI 100), 4,4'-diphenylmethane diisocyanate (MDI) 4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (Polymeric MDI), and xylene diisocyanate.

The content of the aromatic isocyanate is 10 to 50% by weight, preferably 20 to 40% by weight. When the content of the aromatic isocyanate is less than the lower limit, the curing time is prolonged. When the content of the aromatic isocyanate is higher than the upper limit, the curing time may be shortened when the curing agent is mixed with the subject.

Examples of the solvent include at least one selected from the group consisting of xylene, n-butanol, cyclohexanol, cellosolve acetate, and toluene.

The content of the solvent is 1 to 10% by weight, preferably 3 to 8% by weight, considering mixing with the subject.

The weight ratio of the subject to the curing agent is 1: 0.1 to 0.8, preferably 1: 0.2 to 0.5. If the content of the curing agent is less than the lower limit based on the subject, curing may not occur. If the content exceeds the upper limit, a crack may be generated in the preventing layer 300.

The specific gravity of the water-soluble urethane coating material composed of the above-mentioned subject matter and the curing agent is 1.4 to 1.5 at 20 ° C, the viscosity is 100,000 to 120,000 cps at 20 ° C, and the solid content is 92.5 to 93.5%.

The water-soluble urethane-based paint can provide a beautiful appearance because it has excellent self-leveling effect by concealing the rough surface state of the floor of the transportation means provided with the unevenness, and exhibits excellent physical properties such as impact strength, compressive strength and abrasion resistance. Blocking layer 300 may be provided.

The method of applying the water-soluble urethane-based paint is not particularly limited, but it may preferably be applied by one kind selected from the group consisting of spraying, brush, rubber spatula for laying and trowel.

The water-soluble urethane-based coating material may be applied in a predetermined thickness from the upper end of the welded portion or concavities and convexities in one or two to ten times in mm, preferably in a thickness of 1 to 8 mm, Preferably in a thickness (h) of 2 to 4 mm. When the thickness to which the water-soluble urethane-based paint is applied is less than the lower limit value, the noise and vibration generated in the transportation means can be directly transmitted to the person or the object using the transportation means. If the thickness exceeds the upper limit value, It may not be able to block.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example  One.

20% by weight of a water-soluble polyurethane resin (based on 40% by weight of solid content), 22% by weight of polyester polyol, 35% by weight of aluminum hydroxide having an average particle diameter of 1 占 퐉, 15% by weight of barium sulfate having an average particle diameter of 1 占 퐉, % And 3% by weight of xylene.

55% by weight of a polyester polyol, 35% by weight of 4,4'-diphenylmethane diisocyanate (MDI) and 10% by weight of xylene were mixed to prepare a curing agent.

The above-mentioned base and the curing agent were mixed at a weight ratio of 1: 0.3 to prepare a water-soluble urethane-based paint.

Example  2.

25% by weight of water-soluble polyurethane resin (based on 40% by weight of solid content), 40% by weight of polyester polyol, 20% by weight of aluminum hydroxide having an average particle diameter of 1 占 퐉, average particle diameter of 1 占 퐉 5% by weight of barium sulfate, 5% by weight of a flame retardant aid and 5% by weight of xylene were mixed to prepare a water-soluble urethane-based coating material.

Comparative Example  One.

The procedure of Example 1 was repeated except that the acrylic polyol resin was used instead of the water-soluble polyurethane resin to prepare a water-soluble urethane-based paint.

Test Example  1. smoke density

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were applied to a base plate with a rubber spatula for installation at a thickness of 2.1 mm (weight 80 g) and measured according to the ASTM E 662-09 test method.

Example 3 was prepared in the same manner as in Example 1 except that the water-soluble urethane-based paint prepared in Example 1 was applied on a base plate with a rubber spatula to a thickness of 1 mm and then a synthetic rubber plate was provided on the entire surface of the water- The water-soluble urethane-based coating material thus prepared was applied to a thickness of 1.1 mm.

division Ds (90 s) Ds (240 s) Ds (600 s) Dm Time to Dm (s) Tc (%) Dm (corr) Example 1 8.7 18.1 93.1 147 1040 87.7 147 Example 2 15.8 29.2 97.4 158 1187 90.4 164 Example 3 7.9 17.0 89.4 129 912 74.1 121 Comparative Example 1 50.8 103.4 295.4 198 1987 95.4 197

As shown in Table 1, it was confirmed that the smoke density of the sheet (prevention layer) coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention was superior to that of Comparative Example 1.

In particular, in the safety standards of railway vehicles, the values of Ds (240 s) should satisfy 100 or less. In Examples 1 to 3, however, it was confirmed that Comparative Example 1 did not satisfy the above criteria.

Test Example  2. Toxicity index (R)

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were applied to a base plate with a rubber spatula to a thickness of 2.1 mm (weight 80 g) and measured according to the BS 6853 Annex B.2: 1999 test method .

In Example 3, the same method as that in Test Example 1 was used.

division CO2 CO NOx SO2 HCl HCN HBr HF R Example 1 1636 29.50 1.42 1.43 - - - - 0.44 Example 2 2146 51.49 2.94 14.11 - - - - 0.99 Example 3 1634 29.48 1.39 1.37 - - - - 0.43 Comparative Example 1 7989 130.41 5.9 41.2 - - - - 2.4

As shown in Table 2 above, the toxicity index of the sheet coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention was found to be superior to that of Comparative Example 1.

Particularly, in the railway vehicle safety standards, the values of R (toxicity index) should satisfy 1.6 or less. In Examples 1 to 3, however, it was confirmed that Comparative Example 1 did not satisfy the above criteria.

Test Example  3. Oxygen index

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were applied to a base plate with a rubber spatula for installation at a thickness of 2.1 mm (weight 80 g) and measured according to the ISO 4589-2: 1996 test method.

In Example 3, the same method as that in Test Example 1 was used.

division Oxygen concentration (%) Burning time (s) Length exposed to fire (Length burnt, mm) Response Oxygen Index (OI) Example 1 80 <180 <50 ○ over 90 85 <180 <50 ○ 90 <180 <50 ○ Example 2 80 <180 <60 ○ More than 80 85 <180 <60 ○ 90 <180 <60 ○ Example 3 80 <180 <50 ○ over 90 85 <180 <50 ○ 90 <180 <50 ○ Comparative Example 1 80 <180 <70 x 15 85 <180 <70 x 90 <180 <70 x

As shown in Table 3, the oxygen index of the sheet coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention was found to be superior to that of Comparative Example 1.

In particular, in the railway vehicle safety standard, the oxygen index (OI) value should satisfy 35 or more. In Examples 1 to 3, however, it was confirmed that Comparative Example 1 did not satisfy the above criteria.

Test Example  4. Flame propagation

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were applied to a base plate with a rubber spatula for installation at a thickness of 2.1 mm and measured according to the ISO 5658-2: 2006 test method.

In Example 3, the same method as that in Test Example 1 was used.

division Burning time (s) Size shot in fire (mm) CFE (KW / m 2) Qsb (MJ / m 2) Example 1 95 346 54.4 8.81 Example 2 95 412 59.5 18.45 Example 3 95 311 509 8.01 Comparative Example 1 95 609 78.9 34.82

-CFE: critical flux at extinguishment

 Qsb: Average heat for sustained burning

As shown in Table 4, it was confirmed that the flame spread of the sheet coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention was superior to that of Comparative Example 1, and thus the flame retardancy was superior to that of Comparative Example.

Test example 5. Vibration attenuation measurement

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were coated with 250 (L) X25 (W) X 2.0 mm with a rubber spatula for laying and measured according to the KS D 0076 test method, And the loss coefficient at the natural frequency and the natural frequency in the frequency response function curve was obtained by the half-width method.

In Example 3, the same method as that in Test Example 1 was used.

Temperature: 24.5 to 25.5 DEG C; Relative humidity: 45-55% R.H .; Atmospheric pressure: 1013.1 hPa

division Natural frequency (Hz) Loss factor (%) Example 1 254.05 8.5 Example 2 295.17 6.4 Example 3 200.01 9.9 Comparative Example 1 342.49 0.05

As shown in Table 5, it was confirmed that the sheet coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention showed excellent vibration damping.

Test Example  6. Measurement of sound insulation performance

The water-soluble urethane-based coatings prepared in Examples 1 and 2 and Comparative Example 1 were coated with 250 (L) X25 (W) X 2.0 mm with a rubber spatula for installation and measured according to the ASTM E 413: 2010 test method, And the Rw value was determined by measuring according to the ISO 171-1: 1996 test method. The STC value was calculated from 18 bands of 100 ~ 5000Hz of 1/3 octave band.

In Example 3, the same method as that in Test Example 1 was used.

- Temperature: 24.1 ± 0.5 ° C; Relative humidity: 44 ± 5% R.H.

division STC Rw (C; Ctr) Example 1 29 dB 29 (-1; -3) dB Example 2 28 dB 28 (-1; -3) dB Example 3 29 dB 29 (-1; -3) dB Comparative Example 1 25 dB 25 (-1; -3) dB

As shown in Table 6 above, the sheet coated with the water-soluble urethane coating material prepared according to Examples 1 and 2 of the present invention had a sound insulation rating (STC) of 28 to 29 dB, .

Specifically, the STC value of Example 1 was calculated by the following data.

Frequency (Hz) Acoustic transmission loss (dB) Frequency (Hz) Acoustic transmission loss (dB) 100 16.2 800 27.2 125 18.8 1000 29.2 160 20.8 1250 31.5 200 19.3 1600 33.1 250 19.2 2000 35.2 315 22.2 2500 36.9 400 22.5 3150 38.4 500 24.8 4000 39.7 630 25.2 5000 40.7

1: a vehicle body lower frame upper surface 2: a vibration damping sheet
3: anti-vibration rubber 4: support
5: Insulation material 6:
7: connecting iron plate for fitting 8: connecting connecting iron
9: screw 10: crevice filler
11: Stacking paper
100: construction site 200: primer layer
300: Noise and vibration prevention layer

Claims (12)

Coating a water-soluble urethane-based paint on a bottom of a welded portion or a transportation means having a plurality of unevenness to form a flat sheet,
The water-soluble urethane-based paint includes a water-soluble polyurethane resin, a plasticizer, an aluminum hydroxide, a barium sulfate, a flame-retarding auxiliary agent, and a solvent; And a curing agent comprising a plasticizer, an aromatic isocyanate, and a solvent. The method according to claim 1, wherein the water-soluble urethane-based paint is applied as one kind selected from the group consisting of spraying, a brush, a rubber spatula for laying, and a trowel. [2] The method of claim 1, wherein the water-soluble urethane-based paint is applied once or two to ten times from the welded portion or the top of the concavo-convex portion. 2. The method according to claim 1, wherein when the water-soluble urethane-based paint is applied two to ten times, a sound-insulating material is additionally provided between the layers coated with the water-soluble urethane-based paint. Construction method for blocking. The method according to claim 4, wherein the sound insulating material is at least one selected from the group consisting of steel plates, rubber plates, cement plates, and plastic plates. The method of claim 1, wherein the water-soluble urethane-based paint is applied at a thickness (h) of 1 to 8 mm from the welded portion or the top of the concave-convex portion. The method according to claim 1, wherein the water-soluble urethane-based paint is applied at a thickness (h) of 2 to 4 mm from the welded portion or the top of the concavo-convex portion. delete The composition according to claim 1, wherein the subject is selected from the group consisting of 5 to 25% by weight of water soluble polyurethane resin, 10 to 40% by weight of plasticizer, 20 to 70% by weight aluminum hydroxide, 5 to 40% by weight of barium sulfate, 1 to 20% 1 to 10% by weight of a solvent; Wherein the curing agent comprises 40 to 80 wt% of a plasticizer, 10 to 50 wt% of an aromatic isocyanate, and 1 to 10 wt% of a solvent. The method of claim 1, wherein the base and the curing agent are mixed at a weight ratio of 1: 0.1 to 0.8. The method according to claim 1, wherein before applying the water-soluble urethane-based paint
Arranging a surface of the vehicle bottom; And
And forming a primer layer on the bottom of the transportation means. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method of claim 1, wherein the transportation means is one selected from the group consisting of a train, a train, a passenger car, and a bus.

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