JPH0140231Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to a radio wave absorber that is attached to a metal structure whose surface is coated, such as a bridge.

[Prior art]

Conventionally, in order to attach a radio wave absorber to the surface of a metal structure coated with anti-corrosion coating such as a bridge, for example,
As shown in the figure, an adhesive 2 was applied to the surface of a radio wave absorbing rubber sheet 1 using a brush or the like, and this coated surface was coated with an anti-corrosion coating via a metal foil 3 as a radio wave reflecting layer and an adhesive layer 4. It is attached to the surface of the metal structure 7.

In this case, in order to protect the side and top surfaces of the radio wave absorber, the side surfaces are sealed with a sealing paint 5 and the surface is covered with a top coat 6.

Note that the metal foil 3 is not necessarily arranged.

However, in such a radio wave absorber, the radio wave absorbing rubber sheet 1 does not have good air permeability, and the metal foil 3 has no air permeability at all. For this reason, if a heavy anti-corrosion coating with a zinc-rich paint layer is applied to the surface of the metal structure 7, the volatilization of the gas generated from the coating will be hindered, and as a result, the metal structure There was a problem in that blisters were formed between the painted surface of No. 7 and the metal foil 3 or the radio wave absorbing rubber sheet 1, which could cause delamination.

[Purpose of invention]

This invention was devised by focusing on such conventional problems, and its purpose is to effectively eliminate blisters that occur between the painted surface of a metal structure and metal foil or radio wave absorbing rubber sheet. to prevent
Thus, it is an object of the present invention to provide a structure of a radio wave absorber that prevents delamination between layers and protects the adhesive from deteriorating.

[Structure of the idea]

In order to achieve the above object, this invention has a structure of a radio wave absorber in which a metal foil is bonded to a radio wave absorber rubber sheet via an adhesive, in which the radio wave absorber has a structure in which, in the thickness direction of the radio wave absorber rubber sheet body, The gist is that a plurality of continuous ventilation holes are formed whose cross-sectional area becomes smaller in sequence from the metal foil side toward the front side of the rubber sheet main body.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

In the following description, the same components as in the conventional example are denoted by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows a cross-sectional view of a radio wave absorber 1 implementing this invention, in which a rubber sheet main body 1a and a metal foil 3 are bonded via an adhesive 2 of a certain thickness, and the metal foil 3 is It is attached via an adhesive 4 to the surface of a metal structure 7 (adherend 7) which has been coated with anti-corrosion coating.

Furthermore, surface paints 5 and 6 (eg, breathable Hypalon paint) for protecting the side and top surfaces of the radio wave absorber 1 are applied to the front side of the rubber sheet main body 1a.

A plurality of continuous ventilation holes 8 are formed in the thickness direction of the rubber sheet body 1a from the surface side of the metal foil 3 toward the surface side of the rubber sheet body 1a.

Each of the ventilation holes 8 is formed so that the cross-sectional area becomes smaller sequentially from the metal foil 3 side to the rubber sheet main body 1a side, and the cross-sectional area of the ventilation hole 8 is as follows.
For example, an elliptical shape as shown in Figure 2a, or a second
A cross-shaped one as shown in Figure b is conceivable. That is,
There are no particular limitations on the shape as long as the shape does not impair air permeability due to contraction of the rubber sheet main body 1.

Further, since the length of the elliptical vent hole 8 and the cross-shaped vent hole 8 is 1 to 5 mm, they do not adversely affect radio wave absorption performance or deterioration of adhesive strength.

Further, the size (diameter) of the ventilation hole 8 on the surface side of the rubber sheet is preferably such that it can be filled with the surface coating of the air-permeable Pipalon paint, for example, about 1 mmφ or less.

Further, the ventilation holes 8 may be opened mechanically in the thickness direction using a drill, a cross screwdriver, etc., but they can also be formed by electrical discharge machining or laser processing. It is preferable to provide them regularly at a constant pitch as shown in FIG.

Note that the metal foil 3 may be provided as appropriate and is not necessarily required.

The rubber sheet main body 1 used here may be a general rubber radio wave absorber, such as rubber-ferrite, rubber-ferrite-carbon, or rubber-carbon. The material for the rubber may be any polymer with rubber elasticity, but considering weather resistance, adhesion, workability, etc., chloropyrene rubber, isobutylene-isoprene copolymer rubber, silicone rubber, and chlorosulfonated polyethylene rubber are recommended. , polyether rubber, polysulfide rubber,
Polyurethane rubber, acrylic rubber, etc. are good.

In addition, the adhesive 2 includes acrylic ester,
A chloroprene rubber-based adhesive, a natural rubber-based adhesive, or the like may be used, and it is particularly preferable to use a reactive adhesive.

Further, the metal foil 3 may include aluminum, tin, copper,
Any foil made of a conductive material such as iron may be used, and the thickness thereof is preferably 8 μm or more, preferably 8 to 30 μm from the viewpoint of influence on radio wave reflection performance and economical efficiency.

The adhesive layer 4 may be the same as that used for the adhesive 2.

The metal structure 7 coated with anti-corrosion coating is not particularly limited, and may be, for example, a bridge, a ship, or the like.

Next, Figure 5 shows reflection loss (dB) and rubber thickness (mm).
This is a graph comparing this invention and the conventional one, and shows that the rubber sheet body 1 provided with ventilation holes 8 as in this invention has almost the same reflection loss (dB) as the case without ventilation holes. .

[Effect of idea]

As described above, in the structure of a radio wave absorber in which metal foil is bonded to a radio wave absorber rubber sheet via an adhesive, the metal foil is attached in the thickness direction of the radio wave absorber rubber sheet body. Since we have formed multiple continuous ventilation holes whose cross-sectional area gradually decreases from the surface side to the surface side of the rubber sheet body, the holes drilled in the metal foil surface are of a size that does not impair breathability. Therefore, it is possible to effectively prevent blisters from forming between the metal foil and the adherend, and since the holes on the surface of the rubber sheet are protected by the surface coating, there is no direct sunlight from outside. , which has the effect of protecting the adhesive from deterioration.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a radio wave absorber implementing this invention, Figures 2a and 2b are explanatory diagrams showing the cross-sectional shape of the ventilation holes, and Figures 3 and 4 show the arrangement of the ventilation holes. An explanatory diagram, FIG. 5 is a graph explanatory diagram comparing the reflection loss and rubber thickness of this invention and a conventional one, and FIG. 6 is a sectional view of a conventional radio wave absorber. 1...Radio wave absorber, 1a...Rubber sheet body,
2...Adhesive, 3...Metal foil, 4...Adhesive, 7
...Metal structure, 8...Vent holes.

Claims (1)

[Scope of utility model registration request] In the structure of a radio wave absorber in which a metal foil is bonded to a radio wave absorbing rubber sheet via an adhesive, in the thickness direction of the radio wave absorbing rubber sheet body, from the metal foil side to the surface side of the rubber sheet body. A structure of a radio wave absorber characterized by forming a plurality of continuous ventilation holes whose cross-sectional area gradually decreases.