JPH0731039B2 - Far infrared camouflage sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a sheet used for camouflaging far infrared rays.

<Conventional technology> With recent advances in various defense technologies, there are remarkable advances in detection and reconnaissance technologies.
In addition to the method using ultraviolet rays and radar waves, the method using far infrared rays is drawing attention. In particular, this method differs from the conventional method in that far infrared rays (generally referred to as heat rays) emitted by the detection / reconnaissance target object itself are captured by a catch image, which enables detection during daytime and nighttime. It is generally said that it is extremely preferable as a reconnaissance method for military objects, such as tanks and airplanes, because it is capable of reconnaissance and has a feature that far infrared rays have long wavelengths and are not easily affected by fog, smoke, etc. It is being appreciated.

The detection / reconnaissance technique and the camouflage technique for concealing it are related, and when a new detection / reconnaissance means appears, a means for disguising it is strongly required.

Currently, various methods have been proposed as means for effectively disguising military objects from far-infrared detection / reconnaissance, and as a general method, a relatively thick non-woven fabric excellent in heat insulation,
Alternatively, a camouflage sheet using an aluminum foil or the like having low far-infrared radiation is known, but the heat insulating cloth has a problem in operability of disguising a tank or the like with the sheet in a short time,
Further, although the aluminum foil or the like is lightweight and has no problem in operability, it gives an unfavorable result because it shines against other reconnaissance means, for example, visual (visible light) means.

Furthermore, these items are not ventilated and are easily affected by the wind, and when installed outdoors they may not be stable and may be damaged at times, making it difficult to perform expansion work in the wind. is there.

<Problems to be Solved by the Invention> As described above, there is a strong demand for a camouflage means that is effective and has excellent operability and far better ventilation for far infrared rays.
At present, no useful camouflage material has been found that satisfies these requirements and does not adversely affect other detection / reconnaissance means.

<Means for Solving the Problems> The present invention comprises a sheet in which a synthetic resin tape is woven and woven, and has an irregular surface structure due to the twisting of the tape. A far-infrared camouflage sheet with a transmittance of 20% or less.

First, the sheet of the present invention is appropriately woven from a synthetic resin tape, for example, a tape made of a film or a ribbon tape made of a knitted fabric, and each tape surface is oriented in a random direction by twisting the tape. It has an irregular front (or back) structure and appropriate ventilation.

The sheet having a structure in which the respective tape surfaces are oriented in random directions as described above is produced, for example, by inserting a tape as a weft thread to form a Russell knitted fabric. In this case, since the tape is inserted and knitted in the chain stitches of the knitted fabric, it is appropriately twisted, and the tape surface is oriented randomly between the chain stitches. FIG. 1 is a plan view of the sheet of the present invention showing the state, FIG. 2 is a sectional view taken along the line A-A, and 1 is a synthetic resin tape and 2 is a normal warp forming a chain knit. As shown in FIG. 2, in the sheet of the present invention shown here, the tape surfaces are oriented in random directions, and as a result, the sheet has an irregular surface structure and is sufficiently ventilated. In this case, the warp yarns may be tapes, ordinary yarns or monofilaments.

As means for obtaining a structure in which the respective tape surfaces of the present invention are oriented in random directions, in addition to the above-described method, a loosely twisted tape is used as warp and / or weft to make a rough woven or knitted fabric, or they are arranged in parallel. There is a method in which loosely twisted tapes are arranged and adhered to the surface of a thread, tape, or a coarse knitted fabric.

The sheet of the present invention has a structure as described above and has a far infrared ray straight transmittance of 20% or less, and the transmittance is 20% or less.
If it exceeds%, a sufficient far infrared ray barrier effect cannot be obtained.
According to the structure of the present invention, a part of the far infrared rays emitted from the heat source is randomly reflected on the tape surface constituting the sheet of the present invention, and a part of the far infrared rays is refracted and transmitted according to each incident angle, Further, by absorbing some of the far infrared rays in the tape itself, the far infrared rays emitted from the heat source as a whole are dispersed or diffused in a random direction in the sheet of the present invention, which significantly prevents the far infrared rays from going straight through. It is considered that

In the present invention, if the porosity between the tapes is too large, the linear transmittance of far infrared rays may be high depending on the size of each gap, and therefore the porosity is 50%. % Or less, particularly preferably 20% or less. Further, in the present invention, when the width of the gap is too large, far infrared rays partially pass straight even if the porosity is small. Therefore, the width of the gap is preferably 20 mm or less.
The tape width is preferably 2 to 10 mm.

The synthetic resin tape may be formed from various synthetic resins or synthetic fibers, but far infrared absorbent, for example, inorganic / organic pigments, various ceramic powders, polymer compounds and the like, far infrared absorbing Some material, eg PVA
It is more effective to use a film tape that has fine irregularities on the surface that is expected to have a far-infrared scattering effect, a tape that has a far-infrared reflecting layer on the surface or inside and that does not significantly cause detection by visible light. In particular, in the case of a far-infrared absorbing tape, it is preferable that the absorption rate is 50% or more.

The far-infrared ray straight transmittance, far-infrared ray absorption rate, porosity, and gap width referred to in the present invention are measured (defined) as follows.

Porosity: Shown as a percentage of the area of the void portion in a given area taken by the projection photograph of the sheet of the present invention.

Gap width: Width of the gap part (mm) imaged in the same projection photograph
Indicate. However, in the case of a circle or a square, its diameter,
Or it depends on the length of the side. When the gap width in the sheet is not uniform, many measurements are taken and the average value is shown.

<Function> According to the structure of the present invention, the far infrared rays emitted from the heat source are randomly reflected on the tape surface constituting the sheet of the present invention, refracted and transmitted according to the respective incident angles, and further absorbed by the tape itself. Thus, the sheet layer of the present invention disperses, diffuses or absorbs in a random direction, which prevents the far infrared rays from going straight through.

Such a far-infrared ray barrier effect can be sufficiently achieved even if the present invention is almost transparent to visible light and has a slight gap.

Example 1 A film of polyvinyl alcohol (hereinafter, simply referred to as PVA) and high-density polyethylene (hereinafter, simply described as PE) having a thickness of 50 μm was slit into tapes having various widths, and the tape was formed using a warp knitting Russell machine. By twisting the tape and twisting the tape, PE monofilament 750dr yarns in the warp direction were used to fabricate a far-infrared infrared camouflage sheet having different porosity and tape gap width, which consisted of a chain knit structure.

Using these PVA and PE films before slitting as a control together with these sheets, using the device shown in FIG. 3, the temperature of the hot plate was 60 ° C, the distance between the hot plate and the sheet was 50 cm, and the distance between the sheet and the camera was 10 m. Far-infrared barrier effect was measured. The camera used a thermographer in the wavelength range of far infrared rays of 8 to 13 μm and measured the temperature appearing on the attached television image surface.

The results are shown in Table 1. From this, it was found that the present invention has a remarkable far-infrared ray barrier effect as compared with the control example (film).

<Effect> The far-infrared camouflage sheet of the present invention has a sufficient far-infrared shielding effect, has sufficient ventilation, is lightweight and flexible, and is installed as a far-infrared shielding material. Stable installation is possible without any sway due to wind, etc., and installation work is easy.

Further, the conventional metal materials represented by aluminum foil and the like cause a radar reaction, whereas the sheet of the present invention does not have this concern, and there is no problem even if it is used for a military contrast object.

Further, since it has ventilation, the internal temperature does not rise even if the heating element is covered.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a schematic cross-sectional view taken along the line AA, and 1 shows a synthetic resin tape. FIG. 3 shows a schematic view of the measuring method used in Example 1, where 1 is a heat plate, 2 is a sheet of the present invention, and 3 is a thermographic camera.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location D06Q 1/10 (72) Inventor Shiro Kondo 3-8-2 Nihonbashi, Chuo-ku, Tokyo Kuraray Co., Ltd. (72) Inventor Ichiro Hanamori 1-2-1, Kaigandori, Okayama City, Okayama Prefecture Kuraray Co., Ltd.

Claims (1)

[Claims] 1. A synthetic resin tape comprising a woven sheet, which has an irregular surface structure due to the tape being twisted, and has a far infrared ray straight transmittance of 20%.
The far infrared camouflage sheet is as follows.