JPH0711345Y2 - Camouflage sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a fiber sheet having a camouflage effect on radar, visible light and infrared rays.

<Prior Art> Conventionally, a net having a ribbon-shaped fiber sheet cut with a camouflage against visible light and infrared rays,
It is known as a camouflage net that the sheet is provided with holes or notches and expanded. Recently, in addition to this, examination of a camouflage net, a sheet, etc. that reflects radar and hides objects that are easily detected by radar. Has been done. For example, as a radar camouflage sheet, there is a woven fabric in which a fine fiber mixed yarn or a synthetic fiber filament yarn in which particles of a conductive substance such as carbon particles are mixed and spun is used as a sheet for radar camouflage. It is described in the official gazette.

<Problems to be solved by the invention> It is well known that a conductive material such as a metal is effective as a material that reflects a radar and exhibits a camouflage effect on the radar. 3
When a very fine fibrous conductive material such as filament mixed and spun with fine metal wires and conductive material as described in 4099 is mixed with the woven fabric, these materials are allowed to be present at high density in the woven fabric. If there is no radar disguise effect, it is necessary to use the yarn including the metal thin wire or the like for all warps and / or wefts for this purpose. Therefore, such a woven fabric has a high cost, and in addition, there is a problem in workability such as cutting and danger in handling in the case of using a fine metal wire, for example. Further, synthetic fiber filaments mixed with conductive particles generally have a high surface electric resistance of 10 ⁵ Ω · cm or more, and the conductivity is insufficient, so that the radar reflection effect cannot be sufficiently obtained.

The present inventors need to form a conductive layer having at least a certain width or thickness and conductivity when obtaining a product having radar reflectivity using a fiber sheet such as a woven fabric. , And under such conditions,
It has been found that the conductive layer does not need to be present at a high density, and based on this, the present invention intends to provide a camouflage sheet having a high radar reflection effect, which has good processability and handleability and can be manufactured at low cost. To do.

<Means for Solving Problems> The present invention provides a surface of at least a surface of a fiber sheet at least on the surface under the condition that the relation between the line a, the line arrangement pitch b, and the line distance c satisfies the following formula. A camouflage sheet in which a conductive thin layer of filaments having an electric resistance of 10 ² Ω · cm or less is integrated, and the surface of which is coated with a camouflage resin layer for visible light and infrared rays.

0.5 ≤ a ≤ 10 (mm) 1 ≤ b ≤ 10 a (mm) c ≤ 30 (mm) The fibrous sheet constituting the base fabric of the present invention is knitted fabric,
Nonwoven fabric, paper, etc. are used, but especially when the sheet of the present invention is used as a leaf-shaped element cut into a ribbon shape and attached to a net, a perforated sheet having a large number of holes or incisions formed therein, strength, etc. Woven fabric is effective from the point.

In the present invention, as the means for forming the conductive thin layer on the surface of the fiber sheet, when the conductive thin layer is a metal,
The generally known metal plating method, a method of transferring a thin metal layer formed by vapor deposition on a film onto a woven fabric, etc., a sputtering method, a vapor deposition method, an ion plating method, a method of bonding a metal foil, etc. When the conductive thin layer is a conductive resin layer that is appropriately adopted, various coating methods, printing methods, film laminating methods and the like are selected. In the present invention, a metal is particularly preferable as the conductive thin layer.

The conductive thin layer may have a thickness of about 0.1 to 10 μm, but the surface electric resistance of this layer needs to be 10 ² Ω · cm or less,
Above this, when the layer is present in the filament, the radar reflectance as a sheet is small and the radar camouflage effect is difficult to obtain. As the conductive resin, a mixture of various conductive fine particles is used.

Further, in the present invention, the conductive thin layer is formed in the form of filaments on at least the surface of the fiber sheet, and the entire arrangement is such that straight or corrugated curves are arranged in one direction,
One in which the straight lines or curves are arranged so as to intersect in two or more directions can be arbitrarily selected. In particular, from the viewpoint of workability in forming the conductive thin layer, it is preferable to use a combination of straight lines, for example, a polygonal mesh array such as a stripe pattern, a triangle, or a quadrangle.

The width a of the filaments is 0.5 mm or more, the arrangement pitch b of the filaments is 1 mm or more, 10 times or less of the filament width a, and the distance c between the filaments is 30 mm or less, which satisfies these ranges. At this time, sufficient radar reflectivity is obtained. The one in which a conductive thin layer is formed on the entire surface of the fiber sheet has good radar reflectivity, but when the layer is a metal layer, the adhesion with the camouflage layer coated thereon is not easy, and Since the layer is seen through the camouflage coating layer and the surface camouflage effect is reduced, it is necessary to thicken the camouflage layer, which is disadvantageous in handling and the like. Further, if the line width a is too narrow, the radar reflection effect is small unless the inter-line distance c is made small. Therefore, when an attempt is made to obtain a sufficient radar reflection effect, the same as when a conductive thin layer is formed on the entire surface. May cause inconvenience. It should be noted that even if the line width becomes too wide, it is inconvenient as in the case where the conductive thin layer is formed on the entire surface. Further, if the distance between the filaments is 30 mm or more, the radar penetrates from this portion and the radar reflectance as a sheet decreases.

In the present invention, the preferred arrangement of the conductive thin layers of the filament is the filament width a.
Is 1 to 5 mm and the distance c between the filaments is 3 to 20 mm.

In the present invention, the linear arrangement pitch b and the inter-linear distance c are measured at the maximum distance between adjacent linear lines (see FIG. 2).

In the present invention, as the camouflage resin to be coated on the conductive thin layer, a conventionally well-known one is adopted, and a resin containing a pigment corresponding to an environmental color, an infrared reflecting or absorbing substance is appropriately used, Is applied on the sheet by a coating method, a film laminating method, a printing method or the like.

In the sheet of the present invention, it is possible to partially change the reflectance of the radar and enhance the camouflage effect by partially changing the thickness, the line width, the pitch, etc. of the conductive thin layer.

1 and 2 are plan views of the sheet of the present invention, which is partially peeled off, where 1 is a fibrous sheet, 1 is a linear conductive thin layer, and 3 is a camouflage resin coating layer.

<Operation and effect> The sheet of the present invention has a conductive thin layer of filaments existing under the above-mentioned conditions, which is used for radar with wavelengths in the range of 1 GHz to 40 GHz.
Reflects 0% or more, and also has a camouflage effect for visible light and infrared rays, which is cut into ribbons and attached at a net or randomly, or various holes or cuts are made in the sheet to form a porous sheet. When the above-mentioned thing is spread and used for camouflage, the directionality of each sheet (ribbon) surface at the time of use becomes complicated and the radar diffusely reflects, so that the camouflage effect becomes extremely high.

Further, the sheet of the present invention is superior in workability and handleability to the sheet using thin metal wires and can be manufactured at low cost.

Example 1 A surface of a woven fabric made of polyester yarn was applied with a lattice-shaped nickel mica (thickness 0.6 μm) by the following method, and further, a pigment having an infrared camouflage property (high reflectance at 700 to 1200 nm) and A polyvinyl chloride resin mixed with a stabilizer was coated as a camouflage layer by the method of coating. The surface electric resistance of this metal plating layer is 0.1 Ω · cm.

In this case, the line width a of the mating portion, the line arrangement pitch b,
Fig. 3 shows the results of measuring the reflectance for a 10 GHz radar by changing the distance c between the filaments.

(Mettsuki method) The polyester cloth which has been subjected to the refining pretreatment is subjected to the above a, b and c.
After the sensitization and activation treatment were carried out in a grid pattern (the same size as the warp and weft) by the known method, nickel plating was carried out in an acidic bath using sodium hypophosphite as a reducing agent.

The radar reflectance is measured by the method shown in FIG. That is, 10.5 from the radar transmitter shown in FIG.
The microwave of GHz is flown, and the sample 5 placed 100 cm ahead
Apply at the angle shown. Then, the reflected microwave is measured by the receiver 6 (diode for microwave detection) placed at the position shown in FIG. The reflectance (%) is calculated from the following formula.

Reflectance (%) = I / I ₀ × 100 where I ₀ : current value (A) when an iron plate is attached instead of the sample I: current value (A) when the sample is attached

[Brief description of drawings]

1 and 2 are plan views of the sheet of the present invention with a part thereof peeled off. FIG. 3 is a diagram showing the relationship between the inter-striation separation and radar wave reflectance, and FIG. 4 is a diagram showing the arrangement of devices for measuring radar reflectance.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yoshiteru Matsuo Yoshiteru Matsuo Kuraray Co., Ltd. 1621 Sakata, Kurashiki City, Okayama Prefecture (72) Inventor Ichiro Hanamori 1-1239 Umeda, Kita-ku, Osaka City, Osaka Kuraray Co., Ltd. (72) Inventor Minoru Maekawa 1-1239 Umeda, Kita-ku, Osaka-shi, Osaka Kuraray Co., Ltd.

Claims (7)

[Scope of utility model registration request] 1. A fiber sheet having a surface electrical resistance of 10 ² Ω · cm or less on at least the surface of the fiber sheet under the condition that the relationship between the line width a, the line arrangement pitch b, and the line distance c satisfies the following formula. A camouflage sheet in which the conductive thin layers of filaments are integrated and the surface of which is covered with a camouflage resin layer for visible light and infrared rays. 0.5 ≦ a ≦ 10 (mm) 1 ≦ b ≦ 10a (mm) c ≦ 30 (mm) 2. The camouflage sheet according to claim 1, wherein the conductive thin layer is a metal layer. 3. A camouflage sheet according to claim 1 or 2, wherein the line width a is 1 to 10 mm. 4. The camouflage sheet according to any one of claims 1 to 3, wherein the conductive thin layer has a stripe shape. 5. The camouflage sheet according to any one of claims 1 to 4, wherein the conductive thin layer has a polygonal mesh pattern. 6. A utility model registration claim in which the fiber sheet is selected from knitted fabric, non-woven fabric and paper.
~ The camouflage sheet according to any one of items 5 to 5. 7. The camouflage sheet according to claim 1, wherein the conductive thin layer is a metal plating or a metal thin layer formed by a metal transfer method.