JPH0321952Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The invention relates to a sheet-like structure with high ultraviolet reflection efficiency, and more specifically, a sheet-like structure that can hide goods, personnel, etc. from the naked eye and ultraviolet observation in snowy areas. Regarding structures.

[Prior art and its problems]

It is well known that white sheets are used in snowy areas to hide items, personnel, etc. from the naked eye or from observation by ultraviolet light. Furthermore, a white reflective composite sheet having a sheet-like white UV reflective outer layer has been proposed in order to hide it from viewing means such as a camera equipped with a UV transmitting filter (Tokuko Sho).
Publication No. 57-17712, Special Publication No. 57-17711). The white reflective composite sheet is in line with the present invention in terms of its high ultraviolet reflection efficiency, but it is a composite sheet consisting of a base layer and an outer layer, and the outer layer is a so-called resin layer containing a thermoplastic polymer material and an ultraviolet reflector. It has the following drawbacks. That is, when a person works inside the white reflective composite sheet because it has no air permeability, it is necessary to provide a separate ventilation hole. Furthermore, conventional products have the disadvantage that they are heavy and inconvenient to handle, and cannot be made into clothing. For this reason, a satisfactory result has not yet been obtained.

[Purpose of this invention]

The present invention is intended to improve the above-mentioned drawbacks of the prior art, and its first purpose is to make it possible to provide a sheet-like structure with a uniform structure and high ultraviolet reflection efficiency. The second objective is to provide a sheet-like structure that is highly flexible and has a high ultraviolet reflection efficiency and can be used as clothing. The third object is to provide a sheet-like structure that is highly breathable and does not require additional ventilation holes.

[Structure of the present invention]

In order to achieve the above object, the present invention consists of the following configuration.

"A fabric-like fiber sheet having a coating-like or laminated-like surface layer, the surface layer is white and formed from a resin coating having surface irregularities with an average period of 100 to 600 millimicrons, and the sheet is exposed to ultraviolet rays of 360 millimicrons. A UV reflective sheet characterized by having a scattering reflection efficiency of 50% or more and having ventilation pores.'' In this invention, the term "sheet" refers to a woven fabric, knitted fabric, nonwoven fabric, etc. coated or laminated with a resin, etc. .

The surface of the resin coating constituting the surface layer of the present invention is characterized in that the average period of depressions and depressions is 100 to 600 millimicrons. The convex portions referred to here are the fine striped parts that are brightly visible in Figure 2, which will be described later, and the concave portions are the dark areas (including ventilation pores) between the convex portions. . The resin coating shown in FIG. 2 is composed of the above-mentioned uneven portions and flat portions, and the ultraviolet reflection effect is exerted in the uneven portions.
In other words, since the size of the flat part itself exceeds 600 millimicrons, it does not reflect ultraviolet rays, but if the uneven part exists without directionality as shown in Figure 2, it will not reflect light from any angle. Since the light can be scattered and reflected, the reflection efficiency is high. The sheet of the present invention satisfies UV reflection and breathability at the same time due to the uneven portions and pores. In other words, if the average distance between the convex portions or concave portions described above is within the above range, the ultraviolet rays will be scattered and reflected by the surface unevenness, and the ultraviolet rays will be scattered and reflected from all angles when light is received from any angle. The efficiency will be high.

Therefore, if the above value is less than 100 millimicrons,
This is undesirable because it is close to the specular reflection of an aluminum vapor-deposited film and the scattering reflection efficiency is low. Further, if the above-mentioned value exceeds 600 millimicrons, the reflection efficiency of ultraviolet rays decreases, which is not preferable. The ventilation pores may be of any size as long as they are sized to allow gas to pass through, but are preferably 200 to 200 pores.
It is about 1000 millimicrons. Within this range, water vapor is allowed to pass through, allowing the water vapor to evaporate and conversely preventing liquid water droplets from entering from the outside.

Next, the sheet of the present invention has a fiber fabric as one of its constituent elements. The fibers may be continuous filaments or short fibers; continuous filaments are used when resistance to ice and snow is important, and short fibers are used when heat retention and comfort as clothing are important. Good. The fibers are preferably hydrophobic fibers, and known synthetic fibers such as nylon, polyester, polypropylene, acrylic, and vinylon can be used. Among these, fibers that maintain flexibility even at low temperatures, such as nylon, are preferred.

Next, in the present invention, the surface layer may be made of any material as long as it satisfies the above characteristics, but as a preferable example, the main component is polyurethane or soft polyfluoroalkylene (for example, polytetrafluoroethylene, etc.). It is a resin composition that This is because these materials are soft and flexible, and have excellent ultraviolet reflection and vapor transmission properties. This is also because it has excellent lamination properties and coating properties.

In the present invention, at least one side of the sheet-like structure with high ultraviolet reflection efficiency must be white. This is to effectively hide it from the naked eye, and of course it can be white on both sides, but it can also be used with camouflage color on one side, with the white side facing up when there is snow, and the camouflage side facing up when there is no snow. .

At least one side of the sheet-like structure with high ultraviolet reflection efficiency of the present invention must have a scattering reflection efficiency of 50% or more for ultraviolet rays having a wavelength of 360 millimicrons. The scattering and reflection efficiency for ultraviolet light with a wavelength of 360 millimicrons is measured as follows.

The measuring device used was a Hitachi model 323 spectrophotometer.
Using magnesium oxide as a secondary white plate and setting its reflectance to 100%, measure the reflection spectrum of the sample from ultraviolet 210 millimicrons to visible range 700 millimicrons. (The measuring range of the sample is 20 mm in diameter). The reflectance at a wavelength of 360 millimicrons on the reflectance chart thus obtained is read, and this is taken as the scattering reflection efficiency for ultraviolet rays at a wavelength of 360 millimicrons.

The reason why emphasis is placed on scattered reflection in the above is as follows. In addition to scattered reflection, specular reflection is sometimes taken up, but those with high specular reflectance have a glaring luster and are not suitable for the purpose of the present invention. Compared to the specular reflection efficiency, the scattering reflection efficiency is generally lower, and it is difficult to obtain a material with a high scattering reflection efficiency. As a result of various experiments, it was discovered that scattering and reflection efficiency for ultraviolet rays with a wavelength of 360 millimicrons is important to fully demonstrate the effect of concealing items, personnel, etc. on the snow, and that this value must be at least 50%. Ta. Materials with this value less than 50% cannot achieve the object of the present invention.

Next, the seat of the present invention will be explained using the drawings.

Figure 1 shows the cross-sectional layer of the sheet of the present invention, and the magnification is
This is an electron micrograph of 3500. The average size of the ventilation pores is about 400 millimicrons. In addition, the upper part of FIG. 1 shows the white surface layer, and the lower part shows the fiber cross section of the fabric.

Figure 2 shows the surface layer of the sheet of the present invention, and the magnification is
This is an electron micrograph of 3500. The average size of the irregularities on the surface layer is about 550 mm.

[Effects of this invention]

The sheet of this invention has the advantage of providing a UV reflective sheet with high scattering and reflection efficiency, and unlike UV reflective sheets with increased specular reflection efficiency, there is no glare. Excellent for concealing items, personnel, etc. on the snow. Furthermore, since the sheet has air permeability, it has practical value as it is, and of course can be used without making any other holes. The above object can be achieved by sewing simple cloaks, hooded jackets, and pants from the sheet-like structure of the present invention and wearing them on personnel. Furthermore, in the case of a static sheet, it is better to use a sheet made of continuous long fibers, and in the latter case, when used as clothing, spun yarn made of short fibers can be used as a knitted fabric. It can be made to have an excellent combination.

Furthermore, if water repellency is imparted, the practical value will be further improved.

Examples will be described below.

Example 1 Plain woven fabric in which polyester filament yarn 250 denier 72 filament drawn yarn is arranged in warp and weft yarns (warp density 58 threads/inch, weft density 47 threads/inch)
A film made by the following method was laminated onto a film (inches, basis weight: 273 g/m ² ). In other words, “Teflon”
(Registered trademark of DuPont, USA) 6A polytetrafluoroethylene was extrusion molded to form a film with a thickness of 1.42 mm, which was stretched to twice the length in both the vertical and horizontal directions at 230°C. This film was laminated to the fabric described above and then treated in a solution containing 1.5% by weight of a fluorine water repellent. Finally, the sheet was heat set at 160°C for 30 seconds.

When the surface of this sheet was photographed using a scanning electron microscope, it was found that numerous convex portions were generated on the surface of the sheet, and the average diameter of the convex portions was approximately 240 millimicrons. Furthermore, the scattering and reflection efficiency of this sheet for ultraviolet rays with a wavelength of 360 millimicrons was 69%. To examine the concealment effect, spread this sheet over the snow and apply a filter that only transmits ultraviolet rays (UV transmitting visible absorbing filter, UV-D36B, manufactured by Toshiba).
When we took photos with a Polaroid camera attached to the sheet, we obtained very good results, with the boundary between the sheet and the snow almost indistinguishable. Furthermore, even when viewed with the naked eye, the boundary between the fabric and the snow was unclear, indicating that it had a sufficient concealing effect.

Furthermore, this sheet has vent holes that are slightly smaller than the convex portions, so it maintains sufficient gas permeability and does not feel stuffy even in the wear test.

[Brief explanation of the drawing]

Figure 1 shows the cross-sectional layer of the sheet of the present invention, and the magnification is
This is an electron micrograph of 3500. The average size of the ventilation pores is about 400 millimicrons. In addition, the discontinued part in FIG. 1 is the white surface layer, and the lower part shows the fiber cross section of the fabric. Figure 2 shows the surface layer of the sheet of the present invention, and the magnification is
This is an electron micrograph of 3500. The average size of the irregularities on the surface layer is about 550 mm.

Claims (1)

[Claims for Utility Model Registration] (1) A fabric-like fiber sheet having a coating-like or laminated-like surface layer, the surface layer being white and formed from a resin coating having surface irregularities with an average period of 100 to 600 millimicrons. , and the sheet has a scattering reflection efficiency of 50% or more for ultraviolet rays of 360 millimicrons and has ventilation pores. (2) The ultraviolet reflective sheet according to claim 1, wherein the surface layer is a resin composition containing polyurethane as a main component. (3) The ultraviolet reflective sheet according to claim 1, wherein the surface layer is a resin composition containing soft polyfluoroalkylene as a main component.