JPH0734044B2 - Ultraviolet reflective sheet for camouflage used in snowy areas - Google Patents

Description

TECHNICAL FIELD The present invention relates to a camouflage ultraviolet reflective sheet for use in a snowy area, which is effective for hiding an object existing in an environment such as a snowy field.

(Prior Art) It has long been practiced to disguise field battles and to apply camouflage to military bases, military equipment, etc. that creates an illusion of objects in the environmental area.

For example, camouflage in the Arctic is based on white, dark green to hide certain objects in the forest environment,
The color tone of camouflage is generally based on yellow, etc., and in areas where soil is the main constituent, it is based on dark brown.

As a conventional method for hiding military objects in snowy areas, a white pigment such as titanium dioxide is used to white-process a woven fabric or plastic sheet, and then the white cloth or white sheet is used. Methods of coating objects are known.

(Problems to be solved by the invention) However, while snow reflects 70 to 90% of irradiated ultraviolet rays, conventional white pigments such as titanium dioxide absorb most of the irradiated ultraviolet rays. , It has the property of hardly reflecting.

Therefore, there is a drawback that a portion covered with snow can be easily detected by a measuring instrument such as a remote sensitive computer equipped with a UV-transparent filter.

In order to eliminate such drawbacks, a technique such as a white reflective sheet using powder of magnesium oxide, magnesium carbonate, barium sulfate, zircon oxide or the like in place of titanium dioxide is already known (for example, Japanese Patent Publication No. 57-17711). (Japanese Patent Publication No. 57-17712, Japanese Patent Publication No. 58-36108).

The white reflective sheet using the magnesium oxide or the like,
Although it has more UV reflection effect than the one using titanium dioxide, it has 50% UV reflectance in the wavelength range of 300nm or less.
However, it was not satisfactory because it was able to discriminate sufficiently compared to snow.

(Means for Solving the Problem) As a result of earnest research to solve the above-mentioned drawbacks of the prior art, the present inventor has found that the use of lead white as the white pigment resulted in an extremely excellent ultraviolet reflectance near 300 nm. The present invention has been completed by finding that a reflective sheet can be obtained.

That is, the present invention contains lead white as a white UV reflector in the range of 50 to 180 wt% of the base sheet, and 300 to 700 n.
A UV-reflecting sheet for camouflage used in snowy areas, which has a reflectance of 90% or more over the entire wavelength range of m.

Hereinafter, the present invention will be described in detail. Lead white used in the present invention means lead hydroxycarbonate 2PbCO ₃ .Pb (OH) ₂ .

Examples of the material of the reflection sheet that serves as a base material to be colored with lead white in the present invention include polyamide-based, polyester-based, polyacrylic-based, acetate-based, polyvinyl chloride-based, polypropylene-based woven fabrics, non-woven fabrics, and the like. Synthetic leather, synthetic resin impregnated cloth, polyethylene film, polypropylene film, polyamide film, polyvinyl chloride film, polyvinylidene chloride film, polyethylene terephthalate film, etc., including flexible or rigid sheet plates.

As a method for coloring a woven fabric, a non-woven fabric, a plastic film or the like with lead white according to the present invention, in the case of a woven fabric or a non-woven fabric, lead white is blended with a binder such as an acrylic resin or a polyurethane resin to obtain an oily or water-based material. As a paint, a method of impregnating or coating this paint on a woven fabric or a non-woven fabric. In the case of synthetic fiber, lead white is blended when melt-spinning without post-coating, etc. A method of woven or non-woven with fibers is also effective.

Further, as a method of coloring the plastic film material with lead white, (1) a method of blending in the plastic at the time of making the film, that is, blending lead white, and if necessary, a stabilizer, a plasticizer, an antioxidant A method of forming a film or sheet by a conventional method of blending an agent or the like and extruding by a T-die method, an inflation method, or forming a film by a calendar method, (2) a surface of a plastic film manufactured by an appropriate method There is a method of applying coloring for ultraviolet reflection by applying a polymer solution or dispersion containing lead white to the above.

As the binder used in the coating liquid in the method (2), one having excellent adhesiveness to the base film is used. Acrylic resins, polyurethane resins and the like are useful as the polymers used in this.

The lead white used in the camouflage UV reflecting sheet of the present invention is 20 to 200% by weight, preferably 50% by weight, based on the sheet substrate.
Used in an amount of ~ 180% by weight.

When the amount of lead white is less than 20% by weight, the ultraviolet reflectance of the obtained ultraviolet reflective sheet for camouflage is insufficient and the hiding property is insufficient, which is not preferable. On the other hand, if the amount is more than 200% by weight, the bending flexibility of the obtained sheet is lowered and becomes hard, the sheet is easily broken at low temperature, and the ultraviolet reflectance is not improved so much, which is not preferable.

Further, in the camouflage UV reflecting sheet of the present invention, flame retardants such as chlorinated paraffin and antimony trioxide and other various additives can be used together with the lead white.

Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 and Comparative Examples 1 to 4 A vinyl chloride resin sol was prepared by kneading the compounds shown in Table 1 with a roll mill, and the resulting mixture was applied evenly to a Tetoron / cotton blended fabric to a thickness of 0.3 mm. The film was heat-cured at 200 ° C. for 10 minutes to obtain a UV-reflecting sheet for camouflage of the present invention.

The ultraviolet reflectance of the obtained sheet was measured with a Hitachi 330 type self-recording spectrophotometer (measurement, reflection integrating sphere). The result is the second
The results are shown in the table and FIG.

Examples 2 to 3 and Comparative Examples 5 to 12 The formulations shown in Table 3 were calendered to obtain a 0.1 mm thick UV reflective sheet for camouflage of the present invention.

The ultraviolet reflectance of the obtained sheet was measured with a Hitachi 330 type self-recording spectrophotometer (measurement, reflection integrating sphere). The result is the fourth
The results are shown in the table and FIGS. 2 and 3.

(Operation / Effect) The UV-reflecting sheet for camouflage of the present invention, when placed on a snow surface, has a degree of whiteness that is indistinguishable from snow with the naked eye, and has an ultraviolet ray of 300 to 400 nm, particularly an ultraviolet ray of 350 nm or less. On the other hand, the sheet using zirconium oxide, barium sulfate, magnesium carbonate and magnesium oxide has a reflectance of 60% or less, whereas the reflectance of the ultraviolet reflective sheet for camouflage of the present invention is 95% or more. It shows a reflectance close to that of snow.

Therefore, when the camouflage ultraviolet ray reflective sheet of the present invention is placed on a snow surface, it is difficult to distinguish it from snow not only by the naked eye but also by a high-performance measuring device such as a remote sensitive computer. It is effective as a material for hiding a moving object.

[Brief description of drawings]

FIG. 1 shows the spectral reflectance curves in the ultraviolet and visible regions of the sheets of Example 1 and Comparative Examples 1 to 4, and FIG. 2 shows Example 2 and Comparative Example 5.
The spectral reflectance curves in the UV and visible regions of the sheets from ~ 8 to
The figure shows the spectral reflectance curves of Example 3 and Comparative Examples 9 to 12 in the ultraviolet and visible regions. The vertical axis represents the reflectance (%), and the horizontal axis represents the wavelength of light (nm).

Claims (1)

[Claims] 1. A snowy land characterized by containing lead white as a white ultraviolet ray reflector in an amount of 50 to 180% by weight of a base material sheet, and having a reflectance of 90% or more over a wavelength region of 300 to 700 nm. UV reflection sheet for camouflage used in.