JP2007077696A - Antifouling sound insulation wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound insulation wall capable of having difficulty in making attachment of smudge to both flat section 31 and recess section 33 of the back plate 3 of the sound insulation wall. <P>SOLUTION: The surface of the flat section 31 of the back plate 3 of the sound insulation wall shows hydrophily, and the surface of the recess section 33 is used as an antifouling sound insulation wall having water repellency. After the molding working of a steel plate coated with a hydrophilic fluororesin has been made to the back plate 3 of the sound insulation wall, it is preferable that a water repellent processing agent is applied to the surface of the recess section 33. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antifouling sound insulating wall that hardly adheres to dirt as a sound insulating wall provided on a side portion of a road.

  In order to block noise from automobiles, sound insulation walls combined with sound absorbing materials are installed on the side of the road. On the opposite side of the road surface, that is, on the back side of the surface plate, a colored fluororesin-coated back plate is used mainly for the purpose of improving the scenery of the sound insulation wall in urban areas. However, the back plate is contaminated by automobile exhaust gas, dust, and the like, and the dirt becomes conspicuous within a relatively short period of time.

On the other hand, as a paint for reducing adhesion of dirt outdoors, a paint in which an organic silicate condensate is blended with an organic paint composition has been proposed (Patent Documents 1 to 3). In this type of paint, hydrophilicity is imparted to the coating film surface by the blended organosilicate condensate. When the surface of the coating film becomes hydrophilic, the exhaust gas and dust of the automobile are washed away with rainwater, resulting in a surface on which contaminants are difficult to settle.
WO94 / 6870 JP 7-331136 A Japanese Patent Laid-Open No. 8-12921

  FIG. 1 shows a cross-sectional configuration of the sound insulation wall. The back plate 3 of the sound insulation wall is subjected to concave rib processing in order to increase the strength of the entire sound insulation wall. This part is referred to as a recess 33. When a fluororesin-coated steel sheet having a hydrophilic coating film surface is applied in order to impart antifouling properties to the back plate 3, the flat portion 31 of the back plate 3 is washed away with rainwater and the clean state is maintained. Although it can be maintained, the concave portion 33 has a problem that the antifouling effect is not sufficiently exhibited and streaky dirt adheres. As a result of observing the flow of rain water on the back plate 3 during rainfall, a part of the rain water that flowed down the flat portion 31 of the back plate 3 fell at the lower end 32 of the flat portion, but part of the rain water flowed down the recess 33. The rainwater that flowed down the concave portion 33 contained contaminants that had adhered to the flat portion 31, and it was assumed that streaky dirt adhered to the surface of the concave portion 33. In the flat part 31, rainwater hits the entire surface at the time of rainfall and the pollutant is washed, but since the concave part 33 is not directly hit by rainwater, it is considered that streaky dirt is likely to remain. From this, it was considered effective to prevent rainwater from flowing from the flat portion lower end 32 to the surface of the recess 33 in order to prevent the recess 33 from being soiled.

The present invention has been devised to solve such a problem. The surface of the flat portion 31 of the sound insulating wall back plate 3 has a hydrophilic contact angle of 60 degrees or less, and the surface of the recess 33 has a surface. An object of the present invention is to provide an antifouling sound insulating wall characterized by being water repellency having a water contact angle of 70 degrees or more.

In order to achieve the purpose of the back plate 3 of the sound insulation wall, the surface of the flat portion 31 is made hydrophilic by applying a water repellent treatment agent to the surface of the concave portion 33 after forming a hydrophilic fluororesin-coated steel plate. The surface of the recess 33 can be made water repellent. Thus, by making the surface of the flat part 31 of the back plate 3 of the sound insulating wall hydrophilic and making the surface of the concave part 33 water-repellent, it is difficult for the flat part 31 and the concave part 33 to adhere to dirt and maintain a beautiful state. Can do.

  According to the present invention, since the flat portion 31 of the back plate 3 of the sound insulation wall has a hydrophilic surface, contaminants are washed away with rainwater and a beautiful state is maintained. When the surface of the concave portion 33 is hydrophilic, rainwater is easily transmitted from the flat portion 31 to the concave portion 33, and contaminants washed out from the flat portion adhere to the streaks and are contaminated. On the other hand, if the surface of the recess 33 is made water-repellent as in the present invention, rainwater is repelled at the lower end 32 of the flat portion and drops without dropping through the recess 33 in the form of water droplets, so that the recess 33 is not contaminated.

  As shown in FIG. 1, the sound insulating wall includes a surface plate 1 having a large number of openings, a sound absorbing material 2, and a back plate 3 disposed with a space behind the sound absorbing material 2. The back plate 3 is formed with a concave rib at the center of the back plate in order to increase the strength. This part is referred to as a recess 33. In order to prevent the back plate 3 from being contaminated, the surface of the flat portion 31 is made hydrophilic with a water contact angle of 60 degrees or less, more preferably 50 degrees or less. The surface of the concave portion 33 of the back plate 3 is water-repellent with a water resistant contact angle of 70 degrees or more, more preferably 80 degrees, and still more preferably 90 degrees or more.

  As the material for the back plate 3, a steel plate coated with a colored resin is used. Although the kind of coloring resin is not limited, it is preferable to use the fluororesin which is excellent in durability. Examples of the fluororesin include polyvinyl fluoride, polyvinylidene fluoride, fluoroolefin / vinyl ether copolymer, and the like. An acrylic resin etc. are blended with a fluororesin as needed. The coating of the fluororesin includes a method of coating and baking a fluororesin paint on a steel plate and a method of laminating a fluororesin film. When using a fluororesin paint, the hydrophilic fluororesin-coated steel sheet is formed by painting and baking a paint obtained by adding a hydrophilic compound to a topcoat fluororesin paint. When laminating a fluororesin film, a hydrophilic compound is applied after the lamination and dried to form a hydrophilic layer.

Typical examples of the hydrophilic compound added to the fluorine resin coating or applied to the fluorine film include organosilicate compounds, such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane and the like, and partial hydrolysis condensates thereof. Can do. The surface of the coating film formed from the organic resin paint to which the organosilicate compound is added has hydrophilic groups such as Si—OH, Si—OR (R: C _n H _{n + 1} ) due to the orientation of the organosilicate compound, Shows hydrophilicity. Si-OR itself does not exhibit hydrophilicity, but it is easily hydrolyzed by moisture in the air, rainwater, or the like to change to Si-OH, and thus acts as a hydrophilic group when used outdoors.

  The steel sheet which coats the hydrophilic fluororesin is not particularly limited. Cold rolled steel sheet, hot dip galvanized steel sheet, electrogalvanized steel sheet, molten 5% Al-Zn plated steel sheet, molten 55% Al-Zn plated steel sheet, molten A Zn—Al—Mg alloy-plated steel sheet, a hot-dip aluminum-plated steel sheet, a stainless steel sheet, or the like can be used. In order to improve coating film adhesion and corrosion resistance prior to application of the paint on the substrate, pre-coating treatment such as degreasing, surface conditioning treatment, chromate treatment, phosphate treatment, epoxy resin, polyester, etc. Undercoat such as resin is applied.

  The water repellent treatment agent applied to the recess 33 of the back plate 3 coated with a hydrophilic fluororesin is preferably a silicone resin or a fluororesin. As the silicone resin-based water-repellent treatment agent, the more the methyl groups bonded to Si, the higher the water repellency. Therefore, it is preferable to select a silicone resin having many methyl groups. Crosslinking type resins such as heat curing and moisture curing are preferred. Fluororesin-based water-repellent treatment agents include thermoplastic fluoropolymers such as polyvinyl fluoride, polyvinylidene fluoride, and polytetrafluoroethylene, and thermosetting fluororesins that crosslink fluoroolefin / vinyl ether copolymers with isocyanate, melamine, etc. As a main component, a mixture of other resins such as an acrylic resin and a urethane resin can be used as necessary. The water repellent treatment agent is usually a clear treatment, but a matting agent, an aggregate or a color pigment may be added as necessary.

  A steel plate coated with a hydrophilic fluororesin is formed into a back plate by roll forming, bending by bending, or the like. Thereafter, a water repellent treatment agent is applied to the concave portion 33 of the back plate 3 with a brush, a roller or the like and dried. The water repellent treatment agent may be applied to the entire surface of the concave portion 33, but is preferably applied only to the vicinity of the lower end 32 of the flat portion.

Preparation of fluororesin coated steel sheet:
Surface adjustment and coating-type chromate treatment were applied to a 1.6 mm thick molten Zn-6% Al-3% Mg-plated steel sheet, and an epoxy resin paint was applied and baked to a film thickness of 5 μm to provide a primer. Thereafter, a coating film having a film thickness of a fluororesin-based colored paint composed of polyvinylidene fluoride and an acrylic resin, in which 10% by mass of a partial hydrolysis condensate of tetramethoxysilane as a hydrophilizing agent is added to the solid content of the paint. It was painted and baked to a thickness of 25 μm to produce a hydrophilic fluororesin-coated steel sheet and used in Examples and Comparative Example 2. A fluororesin-coated steel sheet produced in the same manner using a fluororesin-based paint without adding a hydrophilizing agent was used in Comparative Example 1.

Production of sound insulation wall back plate 3:
The fluororesin-coated steel plate was formed into a back plate 3 having concave ribs by roll forming. Thereafter, a moisture-curing silicone resin water repellent was brushed and dried in the vicinity of the flat portion lower end 32 of the concave portion 33 of the hydrophilic fluororesin-coated steel plate, and dried. Further, Comparative Example 1 and Comparative Example 2 were those in which the water-repellent treatment agent was not applied to the concave portions 33 of the fluororesin-coated steel sheet and the hydrophilic fluororesin-coated steel sheet to which no hydrophilizing agent was added.

Evaluation of hydrophilicity and water repellency:
The flat part 31 and the recessed part 33 of the back plate 3 were cut out, and the hydrophilicity and water repellency of the surface were evaluated by the static contact angle with water.
Antifouling rating:
The antifouling property of the sound insulation wall was evaluated based on the soil adhesion state by an outdoor exposure test. A sound insulation wall was installed vertically outside Ichikawa City, Chiba Prefecture, and the state of dirt adhesion on the back plate 3 of the sound insulation wall after 6 months was visually judged. The case where the black streaks were densely attached to the traces of rainwater flowing was evaluated as △, the case where the black streaks were thinly attached to the traces of rainwater flowing was evaluated as △, and the case where no streaks were confirmed was evaluated as ◯. .

  Table 1 shows the results of the antifouling evaluation by the water contact angle and the outdoor exposure test. In Comparative Example 1 in which a non-hydrophilic fluororesin-coated steel sheet was used and the water repellent treatment agent was not applied to the concave portion 33, the concave portion 33 had slight streak, but the flat portion 31 had a streak shape. Dirt was attached. In Comparative Example 2 in which both the flat part 31 and the concave part 33 were made hydrophilic, the flat part 31 did not adhere to the dirt, but the concave part 33 showed streak-like dirt. On the other hand, in the example in which the flat portion 31 was hydrophilized and the concave portion 33 was water repellent, no adhesion of dirt was confirmed in both the flat portion 31 and the concave portion 33, and good antifouling properties were shown.

  In the present invention, the flat portion 31 of the back plate 3 used for the sound insulation wall is made hydrophilic and the concave portion 33 is made water repellent. As a result, the flat portion 31 is washed away with rainwater and is less likely to adhere. Since rainwater does not flow into the concave portion 33, streak-like dirt does not adhere and a beautiful state can be maintained.

Cross section of a sound insulation wall according to the present invention

Explanation of symbols

1: Front plate 2: Sound absorbing material 3: Back plate 31: Flat portion of back plate 32: Lower end of flat portion of back plate 33: Concave portion of back plate

Claims (2)

In a sound insulation wall composed of a surface plate 1 having a large number of openings, a sound absorbing material 2, and a back plate 3 disposed with a space behind the sound absorbing material 2, a water contact angle of a flat portion 31 of the back plate 3 Is an antifouling sound-insulating wall characterized by having a hydrophilicity of 60 degrees or less and water repellency in which the concave contact 33 of the back plate 3 has a water contact angle of 70 degrees or more. The antifouling sound-insulating wall according to claim 1, wherein the back plate (3) has a water-repellent coating formed on the surface of the concave portion (33) after forming a steel sheet coated with a hydrophilic fluororesin.