JP2006284888A - Retroreflective sheet including an information display area that develops color when excited by ultraviolet light - Google Patents

Abstract

【Task】
It has an information display area that is difficult to view under the D65 light source, and can clearly see the information display area under the D65 light source and the additional ultraviolet light, and is not only retroreflective but also excellent in anti-counterfeiting. Provide a reflective sheet.
[Solution]
In the retroreflective sheet including the information display area, the information display area includes an ultraviolet-excited coloring layer formed from a colorant composition that is colored by being excited by ultraviolet rays, and the ultraviolet-excited coloring area is L ^* a using a D65 light source. ^* B ^* Color values measured in the color system (L ₁ ^* , a ₁ ^* , b ₁ ^* ), and color values (L ₂₎ measured using the D65 light source and additional ultraviolet light in the ultraviolet excitation coloring region. ^* , A ₂ ^* , b ₂ ^* ), the hue difference index ΔS ^* represented by the following formula (1) is 14 or more, and the retroreflective sheet.
ΔS ^* = ((a ₂ ^* −a ₁ ^* ) ² + (b ₂ ^* −b ₁ ^* ) ² ) ^1/2 ... (1)
[Selection] Figure 4

Description

  The present invention relates to a retroreflective sheet having a novel structure, and more particularly, to a retroreflective sheet characterized in that an information display area that emits light by ultraviolet rays is provided in a part of the retroreflective sheet.

More specifically, in the retroreflective sheet including the information display area, the information display area includes an ultraviolet-excited color-forming layer formed from a colorant composition that is colored by excitation with ultraviolet light, and the ultraviolet-excited color-generating area is defined as a D65 light source. Table of color values (L ₁ ^* , a ₁ ^* , b ₁ ^* ) measured using the L ^* a ^* b ^* color system and the UV-excited coloring region measured using a D65 light source and additional ultraviolet light The present invention relates to a retroreflective sheet, wherein a hue difference index ΔS ^* represented by the following formula (1) is 14 or more when color values (L ₂ ^* , a ₂ ^* , b ₂ ^* ) are used.
ΔS ^* = ((a ₂ ^* −a ₁ ^* ) ² + (b ₂ ^* −b ₁ ^* ) ² ) ^1/2 ... (1)

The retroreflective sheet of the present invention is a road sign, a sign such as a construction sign, a license plate of a vehicle such as an automobile or a motorcycle, a safety material such as clothing or a life-saving device, a marking of a signboard, various authentication stickers or a reflection Useful for plates and the like.

  Conventionally, a retroreflective sheet that reflects incident light toward a light source is well known, and the retroreflective sheet is widely used in the above-described fields by utilizing the retroreflective property. In particular, the use of retroreflective sheets for various license plates and authentication stickers has increased in recent years.

  As the retroreflective sheet, a sealed lens type retroreflective sheet using a micro glass sphere provided with a specular reflection layer, a capsule lens type retroreflective sheet, and a cube corner type retroreflective sheet using a prism are well known. Yes.

  An example of an encapsulated lens type retroreflective sheet is disclosed in Japanese Patent Application Laid-Open No. 59-71848 (Patent Document 1, corresponding US Pat. No. 4,721,694 and US Pat. No. 4,725,494). ), Which is hereby incorporated by reference into this specific description.

  Examples of capsule lens type retroreflective sheets include Mackenzie's Japanese Patent Publication No. 40-7870 (Patent Document 2, corresponding US Pat. No. 3,190,178), and Macgrass' Japanese Patent Publication No. Sho 52-110592. (Patent Document 3, corresponding US Pat. No. 4.025,159) and Bailey et al., Japanese Patent Application Laid-Open No. Sho 62-121043 (Patent Document 4, corresponding US Pat. No. 5,064,272). Here, the citation of these documents is replaced with this specific description.

Triangular pyramidal cube corner retroreflective sheet is disclosed in Schulz US Pat. No. 3,417,959 (Patent Document 5), Mimura JP-A-2001-26452 (Patent Document 6, corresponding US Pat. No. 6,318,866). No.) and the like, and here, the citations of these documents are replaced with specific descriptions thereof.

  A retroreflective sheet using a colorant that emits light by ultraviolet rays is described in JP-A No. 2003-107225 (Patent Document 7).

However, the retroreflective sheet described in JP-A-2003-107225 tries to match the hue under visible light, reflected light, and ultraviolet light, and the information display cannot be clearly seen. There wasn't.

In addition, Roland's Japanese Patent Application Laid-Open No. 50-47591 (patent document 8) describes daylight (visible electromagnetic radiation emitted from a light source infinitely far from a road safety sign, and the radiation is dispersive. It has a substantial element in the UV band and night light (it is visible electromagnetic radiation emitted from a light source that is relatively close to the retroreflective surface and lined up with the viewer, so the radiation is columnar in the UV band. Have a substantial element) and a retro-reflective display which gives different colors.

However, according to the invention of JP-A-50-47591, when Fluorol 7GA is viewed indoors when amber yellow is outdoors and contains ultraviolet rays, it is bright and shines in yellowish green, and rhodamine 6DGN is red in the room. Oranges that turn orange in the outdoors absorb visible light from daylight and emit visible light. As in this application, they absorb additional ultraviolet light and emit another color. It is not what you have.

JP 59-71848 A Japanese Patent Publication No. 40-7870 JP-A-52-110592 JP 62-121043 A US Pat. No. 3,417,959 JP 2001-26452 A JP 2003-107225 A JP 50-047591

As a result of continuing further improvement studies on the retroreflective sheet using the proposed colorant that emits light by ultraviolet light, the present inventors have confirmed that the information display region is excited by ultraviolet light in the retroreflective sheet including the information display region. include ultraviolet light emitting layer formed from the colorant composition which develops a color, Omoteirochi measured in L ^* a ^* b ^* color system the ultraviolet excitation light emitting area by using a D65 light source (L _{1 ^*,} a 1 _* , B ₁ ^* ) and the colorimetric values (L ₂ ^* , a ₂ ^* , b ₂ ^* ) measured using a D65 light source and additional ultraviolet light for the UV-excited color development region, By using a retroreflective sheet characterized by having a hue difference index ΔS ^* of 14 or more, a retroreflective sheet capable of clearly viewing information display under a D65 light source and additional ultraviolet light was completed.
ΔS ^* = ((a ₂ ^* −a ₁ ^* ) ² + (b ₂ ^* −b ₁ ^* ) ² ) ^1/2 ... (1)

Furthermore, the present inventors have used colorimetric values (L ₃ ^* , a ₃ ^* , b) obtained by measuring an area where information is not displayed on the retroreflective sheet (hereinafter referred to as a non-information display area) using a D65 light source. ₃ ^* ), the color difference ΔE ^* ₁ represented by the following formula (2), or the color display value (L ₄ ^* , a ₄ ^*) measured using 65 light sources in the information display area other than the ultraviolet excitation color development area , B ₄ ^* ), the color difference ΔE ^* ₂ represented by the following formula (3) is 5 or less. By using the retroreflective sheet according to claim 1, information is obtained under a D65 light source. A retroreflective sheet was completed, which is difficult to visually recognize, and allows the information display to be clearly visually recognized under a D65 light source and additional ultraviolet light.
ΔE ₁ ^* = ((L ₃ ^* −L ₁ ^* ) ² + (a ₃ ^* −a ₁ ^* ) ² + (b ₃ ^* −b ₁ ^* ) ² ) ^1/2 ... (2)
ΔE ₂ ^* = ((L ₄ ^* −L ₁ ^* ) ² + (a ₄ ^* −a ₁ ^* ) ² + (b ₄ ^* −b ₁ ^* ) ² ) ^1/2 ...
(3)

Thus, according to the present invention, in the retroreflective sheet including the information display area, the information display area includes an ultraviolet-excited color forming layer formed from a colorant composition that is colored by excitation with ultraviolet light, Color values (L ₁ ^* , a ₁ ^* , b ₁ ^* ) measured in the L ^* a ^* b ^* color system using a D65 light source, and the UV-excited color development region using a D65 light source and additional ultraviolet light Provided is a retroreflective sheet characterized by having a hue difference index ΔS ^* represented by the following formula (1) of 14 or more when measured color values (L ₂ ^* , a ₂ ^* , b ₂ ^* ) Is done.
ΔS ^* = ((a ₂ ^* −a ₁ ^* ) ² + (b ₂ ^* −b ₁ ^* ) ² ) ^1/2 ... (1)

  The retroreflective sheet of the present invention has an information display area that is difficult to view under the D65 light source, and can clearly see the information display area under the D65 light source and the additional ultraviolet light. Also excellent in prevention.

Hereinafter, the retroreflective sheet of the present invention will be described in more detail. As the retroreflective sheet having an information display area in the present invention, an open lens type retroreflective sheet, an encapsulated lens type retroreflective sheet, a capsule lens type retroreflective sheet, a cube corner type retroreflective sheet, or the like can be used.

Hereinafter, the present invention will be described in detail. First, among the cube-corner retroreflective sheets, a triangular pyramid-shaped cube-corner retroreflective sheet which is a typical embodiment will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a triangular pyramid cube corner retroreflective sheet.

(4) is a reflective element layer in which the triangular pyramid-shaped reflective elements of the present invention are arranged in a close-packed manner, (3) is a holding body layer that holds the reflective elements, and (40) is the incidence of light. Direction. The reflective element layer (4) and the holding body layer (3) are usually integrated (5), but separate layers may be laminated. Moisture penetrates the back surface of the surface protective layer (1), the printing layer (2) for coloring to adjust the hue, and the reflective element layer (4) according to the purpose of use and usage environment of the retroreflective sheet in the present invention. A binder layer (7) for achieving an encapsulated sealing structure for preventing the above, a support layer (8) for supporting the binder layer (7), and the retroreflective sheet are attached to another structure. An adhesive layer (9) and a release substrate layer (10) used for attaching can be provided.

The printing layer (2) is usually provided between the surface protective layer (1) and the support layer (3), on the surface protective layer (1), on the reflective surface of the reflective element layer (4), or on the surface protection. When the surface protective layer (1) has two or more layers, it can also be installed between the surface protective layers.

The printing layer (2) can usually be installed by means such as gravure printing, screen printing and ink jet printing.

The material constituting the reflective element layer (4) and the holder layer (3) is not particularly limited as long as it satisfies the flexibility that is one object of the present invention, but is optically transparent. Those having good properties and uniformity are preferred.

Examples of materials that can be used for the reflective element layer (4) in the present invention include polycarbonate resin, vinyl chloride resin, (meth) acrylic resin, epoxy resin, styrene resin, polyester resin, fluororesin, polyethylene resin, and polypropylene resin. Examples of the olefin resin, cellulose resin, and urethane resin. Further, for the purpose of improving the weather resistance, an ultraviolet absorber, a light stabilizer, an antioxidant and the like can be used alone or in combination. Furthermore, various organic pigments, inorganic pigments, fluorescent pigments, dyes, fluorescent dyes and the like can be contained as colorants.

The same resin as that used for the reflective element layer (4) can be used for the surface protective layer (1), but vinyl chloride resin, (meth) acrylic, which is particularly excellent in weather resistance, solvent resistance, printability and the like. Resins are preferred.

In the surface protective layer (1), an ultraviolet absorber, a light stabilizer, an antioxidant and the like can be used alone or in combination for the purpose of improving the weather resistance. Furthermore, various organic pigments, inorganic pigments, fluorescent pigments, dyes, fluorescent dyes and the like can be contained as colorants.

When printing on the surface protective layer (1), it is preferable to adjust the surface tension to be 32 dynes / cm or more in order to improve printing characteristics. In addition to the resin component and the colorant, the printing layer (2) ink may contain, if necessary, a plasticizer, an antifoaming agent, a leveling agent, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a crosslinking agent, and the like. Various additives may be blended, and a solvent may be blended for viscosity adjustment or the like.

The resin component used in the ink is not particularly limited, but is a melamine resin having excellent colorant dispersibility and stability, solubility in solvents, weather resistance, printability, adhesion to a film, and the like. Epoxy resin, urethane resin, vinyl resin, polyester resin, alkyd resin and the like are preferable, and those obtained by copolymerizing these alone or in combination of two or more thereof can be used.

The ultraviolet-excited coloring layer of the present invention may be provided in any layer of the retroreflective sheet. However, like the printed layer, it is provided between the surface protective layer (1) and the support layer (3) or the surface protective layer. It can be placed on the layer (1), on the reflective surface of the reflective element layer (4), or on the surface protective layer. If the surface protective layer (1) has two or more layers, it is placed between the surface protective layers. This is preferable because it is easy to manufacture.

By making the colorant composition that is colored by being excited by ultraviolet rays used in the ultraviolet excitation coloring layer of the present invention light-transmitting, the information display region can have retroreflective performance, and the information display region is visible. Can be improved.

The colorant used in the ultraviolet-excited coloring layer of the present invention is a colorant that develops color when excited by ultraviolet rays. Such a colorant is sold as Auro Rainbow (trade name) by Lintec Corporation and can be suitably used in the present invention.

In the present invention, the information display area was measured in the L ^* a ^* b ^* color system using the D65 light source and the color value measured in the L ^* a ^* b ^* color system and the D65 light source and additional ultraviolet light. The hue difference index ΔS ^* with the color value is 14 or more. If the hue difference index ΔS ^* is 14 or more, the information display area is conspicuous when the D65 light source and the additional ultraviolet light are applied, which is preferable because it is easily visible.

In addition, it is preferable from the viewpoint of forgery prevention that the ultraviolet-excited coloring region is difficult to visually recognize under a D65 light source.

In order to make it difficult to visually recognize the ultraviolet-excited coloring region under a D65 light source, various organic pigments, inorganic pigments, fluorescent pigments, dyes and fluorescent dyes that can be contained in the surface protective layer and the above-mentioned colorants used for printing For example, the ultraviolet excitation coloring region and the non-information display region and / or the non-ultraviolet excitation coloring region can be made to have similar colors, preferably the same color.

The reflective element layer (4) is generally provided with an air layer (6) on the back of the triangular pyramid cube corner retroreflective element for the purpose of increasing the critical angle that satisfies the internal total reflection condition. The reflective element layer (4) and the support layer (8) are preferably hermetically sealed with a binder layer (7) in order to prevent problems such as a decrease in the critical angle due to the ingress of moisture under use conditions.

As the sealing and sealing method, methods disclosed in US Pat. Nos. 3,190,178, 4,025,159, and Japanese Utility Model Laid-Open No. 50-28669 can be employed.

Examples of the resin used for the bonding layer (7) include (meth) acrylic resin, polyester resin, alkyd resin, epoxy resin, and the like. As a bonding method, a known heat-fusible resin bonding method or thermosetting resin bonding method is used. An ultraviolet curable resin bonding method, an electron beam curable resin bonding method, or the like can be appropriately employed.

The binder layer (7) used in the present invention can be applied over the entire surface of the support layer (8), and can be selectively placed by a printing method or the like at the junction with the retroreflective element layer (4). It is.

When the binder layer is formed of the colorant composition that is excited by the ultraviolet ray of the present invention and develops color, only the coupling portion becomes the information display area when the sealed encapsulating structure is formed.

In addition, when the UV-excited color information display layer of the present invention is formed on the binder layer, only the joint portion becomes the information display region when the sealed encapsulating structure is formed.

In these aspects in which only the coupling part is used as the information display area, the displayed information is partially hidden, so that the display part is large enough to recognize the contents of the information even if a part of the display part is missing. Is preferred.

Examples of the material constituting the support layer (8) include a resin constituting the retroreflective element layer (4), a resin capable of forming a general film, a fiber, a cloth, a metal foil or a plate such as stainless steel or aluminum, respectively. Or it can be used in combination.

An adhesive layer (9) used for attaching the retroreflective sheet of the present invention to a metal plate, a wooden plate, a glass plate, a plastic plate, and the like, and a release substrate layer (10) for the adhesive layer (9) are: A known one can be selected as appropriate. As the adhesive, a pressure-sensitive adhesive, a heat-sensitive adhesive, a cross-linking adhesive, and the like can be appropriately selected. Pressure sensitive adhesives such as butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate, etc., obtained by copolymerizing acrylic acid ester with acrylic acid, vinyl acetate, etc. A rubber-based pressure-sensitive adhesive can be used. As the heat-sensitive adhesive, an acrylic resin, a polyester resin, an epoxy resin, or the like can be used.

The ultraviolet light emitting colorant composition used in the present invention is one that develops color when excited by ultraviolet light, but can effectively produce color when a black light having a center wavelength of 352 nm is applied. Cannot produce effective color when black light of 368nm is applied.

Examples of the colorant that absorbs and excites a wavelength of about 360 nm or less and develops visible light include a colorant manufactured by Lintec Corporation, a trade name, an auro rainbow, and the like.

In the retroreflective sheet of the present invention, it is preferable to use an ultraviolet absorber, a light stabilizer, an antioxidant and the like alone or in combination for the purpose of improving the weather resistance.

In addition, it is preferable to further provide a light-transmitting cover film on the light incident side of the retroreflective sheet of the present invention and / or an overlay containing an ultraviolet absorber in the pressure-sensitive adhesive layer in order to further improve the weather resistance. .

When an ultraviolet absorbing layer containing these ultraviolet absorbers is provided on the light incident side of the ultraviolet excitation coloring layer or the ultraviolet excitation coloring layer of the present invention, the ultraviolet excitation coloring layer of the present invention emits light sufficiently. The ultraviolet absorption rate at a wavelength of 360 nm of the ultraviolet absorbing layer is preferably 75% or less, and more preferably 50% or less.

Examples of such ultraviolet absorbers include salicylate-based ultraviolet absorbers such as pt-butylphenyl salicylate, titanium dioxide, and the like.

Such an ultraviolet absorber has an ultraviolet absorption wavelength end of 360 nm or less and does not hinder the color development of the excitation coloring layer, so that the thickness and amount of the ultraviolet absorbing layer can be determined in consideration of weather resistance. .

Further, even with an ultraviolet absorber other than the above, the ultraviolet absorption at a wavelength of 360 nm can be adjusted to 75% or less, preferably 50% or less by adjusting the number of added parts.

Examples of such an ultraviolet absorber include benzotriazole-based ultraviolet absorbers such as 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- Benzophenone ultraviolet absorbers such as hydroxy-4-h-dodecylbenzophenone, cyanoacrylate ultraviolet absorbers such as 2-ethylhexyl-2-cyano-3,3-diphenylcyanoacrylate, 2, (4,6-diphenyl-1 , 3,5 triazin-2-yl) -5 [(hexyl) oxy] -phenol, and other triazine-based UV absorbers, zinc oxide, and the like, and does not interfere with the color development of the excitation color developing layer and has good weather resistance Therefore, the thickness and amount of the ultraviolet absorbing layer can be determined.

The information display area of the present invention may have two or more colors, in which case at least one color is formed from a colorant composition that develops color when excited by ultraviolet rays, and ΔS is 14 or more. The color may be a color that is excited by ultraviolet rays, a color that is not excited by ultraviolet rays, a color that is excited to develop color, or a ΔS of less than 14.

When the information display area is formed with two or more colors, it is preferable that ΔE of each color is 5 or less. This is preferable because it is difficult to visually recognize under the D65 light source and clearly visible under the D65 light source and the additional ultraviolet light.

In addition, as a method of changing the hue, brightness, and saturation of the information display area in gradation (gradation), for example, dot printing is used, and the dot diameter and the interval between dots are regularly changed. it can. Thus, forgery becomes difficult by changing the hue, brightness, and saturation in gradation, which is preferable in terms of prevention of forgery.

Next, an example of a vapor deposition type triangular pyramidal cube corner retroreflective sheet which is another preferable embodiment of the cube corner retroreflective sheet of the present invention will be described with reference to cross-sectional views.

In FIG. 2, the surface protective layer (1), the printing layer (2), the holding layer (3), the reflective element layers (4), (3) and (4) of the vapor deposition type triangular pyramid cube corner retroreflective sheet are integrated. The same material as the triangular pyramid cube corner retroreflective sheet described above may be used for the display (5), the information display area (not shown), the adhesive layer (9), and the release substrate layer (10). it can.

Also in the vapor deposition type triangular pyramidal cube corner retroreflective sheet of the present invention, the same ultraviolet light emitting colorant composition as that used in the aforementioned triangular pyramidal cube corner retroreflective sheet can be used.

In the vapor deposition type triangular pyramidal cube corner retroreflective sheet, the ultraviolet light emitting information display layer is provided on any one of the light incident side of the specular reflection layer, thereby providing an ultraviolet ray having good visibility under D65 light and additional ultraviolet light. A light emitting region can be obtained.

A metallic specular reflection layer (11) is provided on the surface of the reflective element layer (4) of the vapor deposition type triangular pyramid cube corner retroreflective sheet, and an adhesive layer (9) is further formed as a specular reflection layer (11). ) Are directly contacted and laminated. The vapor deposition type triangular pyramidal cube corner type retroreflective sheet in this embodiment does not require an air layer to retroreflect on the specular reflection principle, and therefore does not require a binder layer and a support layer.

The triangular pyramidal cube-corner retroreflective sheet of the present invention is formed on a surface of the reflective element layer (4) from a metal such as aluminum, copper, silver, nickel using means such as vacuum deposition, chemical plating, and sputtering. A specular reflection layer (11) can be provided. Among the methods of providing the specular reflection layer (11), the vacuum vapor deposition method using aluminum can lower the vapor deposition temperature, so that the thermal deformation of the retroreflective element (4) in the vapor deposition process can be minimized. Moreover, since the color tone of the specular reflection layer (11) obtained becomes bright, it is preferable.

The aluminum specular reflection layer (11) continuous vapor deposition apparatus includes a vacuum container capable of maintaining a degree of vacuum of about 7 × 10 ^{−4 to} 9 × 10 ⁻⁴ mmHg, a base sheet installed therein, and a light incident side surface thereof An unwinding device for unwinding the prism raw sheet composed of the surface protective layer laminated thereon, a winding device for winding the deposited prism original sheet, and an aluminum heater with an electric heater in the graphite crucible between them. It consists of a heating device that can be melted. Pure graphite pellets having a purity of 99.99% by weight or more are charged into the graphite crucible, and are melted and vaporized under conditions of, for example, an AC voltage of 350 to 360 V, a current of 115 to 120 A, and a processing speed of 30 to 70 m / min. The specular reflection layer (11) can be vapor-deposited on the surface of the retroreflective element with a thickness of, for example, 800 to 2000 angstroms by the converted aluminum atoms.

Also in the vapor deposition type triangular pyramid cube corner retroreflective sheet used in the present invention, it is possible to use the same colorant composition that is colored by being excited by ultraviolet rays similar to that used in the aforementioned triangular pyramid cube corner retroreflective sheet. it can.

Moreover, the overlay similar to that used for the triangular pyramidal cube corner retroreflective sheet can be used for the overlay, and it is preferably used for improving weather resistance.

FIG. 3 shows an embodiment of a capsule lens type retroreflective sheet used in the present invention.

In FIG. 3, it is a microlens type reflection element having a specular reflection layer (27) on a part of a glass microsphere (23), and a large number of retroreflective elements (23) are arranged in a close-packed manner, and a binder The retroreflective element layer is formed by being embedded and supported so that the mirror reflection layer (27) side of the glass microsphere is embedded in the layer (24). The retroreflective element layer is formed by the retroreflective element (23), the binder layer (24), the surface protective layer (21), and a bonding portion (25) that bonds these layers in a continuous network. An air layer (28) is enclosed in the capsule.

  In the capsule lens type retroreflective sheet, the retroreflective property can be exhibited only by holding the air layer (28) on the surface of the reflective element (23) as described above. The coupling portion (25) holds the air layer (28) and prevents water and the like from entering the surface of the retroreflective element layer. If the surface of the reflective element layer is covered with water or the like, the light incident on the retroreflective element (23) is not focused on the specular reflective layer (27) due to the optical refractive index, and retroreflective. Sexuality is impaired.

Also in the capsule lens type retroreflective sheet of the present invention, the same colorant composition that is colored by excitation with the same ultraviolet rays as that used in the above-mentioned triangular pyramidal cube corner retroreflective sheet can be used.

In the capsule lens type retroreflective sheet of the present invention, the ultraviolet-excited coloring layer is visible even if provided on any layer of the retroreflective sheet, but is provided on the surface of the surface protective layer and / or the back surface of the surface protective layer. However, it is preferable because a clear ultraviolet-excited coloring region can be obtained under D65 light and additional ultraviolet light.

  The capsule including the retroreflective element (23) and the reflective element layer and the air layer (28) in the capsule lens type retroreflective sheet is formed as follows.

(A) Disperse glass microspheres as uniformly as possible on a temporary fixing sheet having a thermal softening layer such as polyethylene on the surface, and embed the lower part of the microspheres in the thermal softening layer by heating;

(B) The glass microsphere temporary fixing sheet obtained in (a) is guided to a metal vapor deposition device, and a metal layer [specular reflection layer (27)] is vapor-deposited on the exposed surface of the glass microsphere,

(C) A sheet of thermosoftening resin that becomes a binder layer (24) or a sheet of glass microspheres having a specular reflection layer (27) embedded in the exposed surface obtained in (b), or as required The heat-softening resin is laminated with a resin sheet for a support serving as a support layer (26) and the heat-softening resin side is pressed with heat to form a specular reflection layer (27) forming portion of the glass microsphere. After being embedded in the thermosoftening resin layer, the temporary fixing sheet is peeled off, and the glass microspheres having the specular reflection layer (27) are transferred to the thermosoftening resin layer,

(D) A resin sheet to be a surface protective layer (21) is laminated on the surface of the glass microsphere side of the sheet obtained in (c), and then behind the binder layer (24) [light incident (40) side From the opposite side], the binder layer (24) is partially deformed by means of heating embossing or the like, and the bonding portion (25) is formed by thermally fusing to the surface protective layer (21),

Or (d ') The surface of the sheet obtained in (c) on the side of the glass microspheres is printed with a mesh shape to form the bonding portion (25) using an appropriate resin, and the surface protective layer (21) is formed thereon. Formed by adhering

(E) Thereby, a capsule surrounded by the surface protective layer (21), the binder layer (24) and the bonding portion (25) and having the retroreflective element layer and the air layer (28) therein is formed.

  The retroreflective sheet further comprises a printed layer for transmitting information to the observer or coloring the sheet, a support (26) for supporting and reinforcing the binder layer, depending on the purpose of use and the environment of use. An adhesive layer (9) and a release material layer (10) for attaching the retroreflective sheet to other structures can be provided.

The printed layer (22) and the information display area are provided on the surface (light incident side surface) or the back surface of the surface protective layer (21) or the surface of the retroreflective element layer, similarly to the cube corner type retroreflective sheet described above. The same colorant can be used.

  As the glass microspheres (23) used for forming the retroreflective element layer, those made of glass having a particularly high light refractive index are used.

Moreover, as a material which comprises each layer of this capsule lens type | mold retroreflection sheet, the thing similar to what was mentioned above about each layer of a cube corner type retroreflection sheet can be used.

Of these layers, the support layer (26) provided as necessary is usually made of a resin that is tougher and more flexible than the material used for the binder layer (24). Then, it can be crosslinked by known means, for example, using isocyanate as a crosslinking agent, or radiation crosslinking.

  In the capsule lens type retroreflective sheet having the above-described configuration, at least one layer closer to the incident light side (the side indicated by the arrow 40 in FIG. 3) than the sealed air layer (18), that is, the surface protective layer in FIG. (1) And / or a printed layer that may be formed, in the same manner as in the case of a cube corner type retroreflective sheet, with a UV absorber and / or a light stabilizer, thereby providing a capsule with excellent weather resistance A lens-type retroreflective sheet can be obtained.

Also in the capsule lens type retroreflective sheet used in the present invention, the same colorant composition that is colored by being excited by ultraviolet rays similar to that used in the aforementioned triangular pyramid cube corner retroreflective sheet can be used.

Moreover, the overlay similar to that used for the triangular pyramidal cube corner retroreflective sheet can be used for the overlay, and it is preferably used for improving weather resistance.

  Next, an encapsulated lens type retroreflective sheet which is an embodiment of another preferred structure of the present invention will be described with reference to FIG. 4 which is a sectional view thereof.

  As shown in FIG. 4, a surface layer (31) made of a transparent resin that supports a large number of high-refractive-index transparent microspheres (33) such as transparent microglass spheres embedded therein, and a diameter in the bead binding layer (34). Are formed along the curved surface of the layer of the transparent microsphere (33) protruding from the bead-binding layer (34), The specular reflection layer (36) to be formed is composed of a focus adjustment layer (35) formed with a constant thickness so as to be almost at the optical focus position of the transparent microsphere (33). The high-refractive-index transparent microsphere (33), the focus adjustment layer (35), and the specular reflection layer (36) are substantially arranged in a positional relationship that optically satisfies the retroreflection condition of light. A reflective element is formed.

The printed layer (32) and the information display area are the surface (light incident side surface) or the back surface of the surface protective layer (31) or the back surface, or retroreflective similarly to the above-described cube corner type retroreflective sheet or capsule lens type retroreflective sheet. It can be provided on the surface of the element layer, and the same colorant can be used.

  As the material constituting each layer of the encapsulated lens type retroreflective sheet, the same materials as described above for the corresponding layers of the cube corner type retroreflective sheet can be used.

  Further, in the encapsulated lens type retroreflective sheet having the above structure, the surface layer and the reflective layer are blended together with the ultraviolet absorber and / or the light stabilizer in the same manner as in the case of the cube corner type retroreflective sheet. An encapsulated retroreflective sheet having excellent weather resistance can be obtained.

  Of the encapsulated lens type retroreflective sheet shown in FIG. 4, the one manufactured by the prior art, that is, the one in which the specular reflection layer is formed by vapor deposition and the manufacturing method thereof are described in detail in Patent Document 1. Here, the citation of this document shall be replaced with its specific description.

Also in the encapsulated lens type retroreflective sheet used in the present invention, the same ultraviolet light emitting colorant composition as that used in the aforementioned triangular pyramidal cube corner retroreflective sheet can be used.

Moreover, the overlay similar to that used for the triangular pyramidal cube corner retroreflective sheet can be used for the overlay, and it is preferably used for improving weather resistance.

The retroreflective sheet of this invention can be used suitably for a license plate.

The license plate in the present invention has a structure in which a retroreflective sheet is laminated on a metal plate such as aluminum or steel plate, or a structure in which a light incident side of a reflective sheet is laminated on a transparent resin plate via an adhesive. .

For example, a police officer can illuminate a license plate with a black light at the time of an inspection or the like, and can read information that is not recognized under visible light and is colored by excitation when irradiated with ultraviolet rays.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Before describing this example and the comparative example, a method for measuring colorimetric values using a D65 light source and a D65 light source including additional ultraviolet light performed on them will be described.

<Color measurement method using D65 light source>
The measurement sample was placed in a dark room, and it was an opaque black film spaced 5 cm square and fixed vertically.

A D65 fluorescent lamp (“FL20S • D-EDL-D65” manufactured by Toshiba Lighting & Technology Co., Ltd.) was irradiated from above the normal of 45 ° on the sample surface. At this time, the position was adjusted so that the illuminance of the sample surface was 1000 lx using an illuminometer (“3281A” manufactured by Yokogawa Corp.). The hue was measured using a spectral radiance meter [“CS-1000A” manufactured by Konica Minolta Co., Ltd.] at a position 1 m from the sample on the normal line of the sample surface to obtain tristimulus values XYZ of light source colors. Samples were measured at five locations and averaged.

A standard white plate with a known spectral reflectance was measured with a spectral radiance meter to obtain a spectral spectrum. The result obtained by dividing the spectral spectrum by the spectral reflectance is calculated according to JIS Z 8701, the light source color tristimulus value XnYnZn of the complete diffuse reflection surface is obtained, and from the tristimulus value XYZ of the measurement sample and the tristimulus value XnYnZn of the complete diffuse reflection surface The chromaticity values of the L ^* a ^* b ^* colorimetric system were calculated according to JIS Z 8729.

<Color measurement method using D65 light source containing additional ultraviolet rays>
In the color measurement method using the D65 light source, in addition to the D65 fluorescent lamp, a black light (“FL20SBLB” manufactured by Toshiba Lighting & Technology Co., Ltd.) was irradiated from below 45 ° normal to the sample surface, and at this time, an ultraviolet intensity meter [Konica Minolta Ltd. "UM-10", using the photodetector "UM-360"], except that the sample surface strength to adjust the position so that 1 mW / cm ² is the same as the color measurement method using the D65 illuminant The chromaticity values of the L ^* a ^* b ^* colorimetry system were calculated.

Example 1
34 parts by weight of green UV-excited coloring pigment (trade name: Aurora Rainbow A160) manufactured by Lintec Corporation, 100 parts by weight of an acrylic resin solution (trade name: Nikkalite N-3612) manufactured by Nippon Carbide Industries Co., Ltd., Nippon Carbide Industries Co., Ltd. 8 parts by weight of an isocyanate-based curing agent (trade name: Nikkalite N-3631) manufactured by mixing was mixed and stirred to obtain an ultraviolet-excited coloring paint 1 having a solid content of about 52% by weight.

Next, the ultraviolet excitation coloring paint 1 is screen-printed on a white encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen, and the ultraviolet excitation coloring information display area is displayed. A retroreflective sheet containing was obtained.

Example 2
Example 1 is the same as Example 1 except that UV-excited color-coating paint 2 was obtained by using 34 parts by weight of blue UV-excited color pigment (trade name: Aurora Rainbow A180) manufactured by Lintec Corporation instead of green UV-excited color pigment. Similarly, a retroreflective sheet including an ultraviolet-excited color information display area was obtained.

Example 3
34 parts by weight of green UV-excited coloring pigment (trade name: Aurora Rainbow A160) manufactured by Lintec Corporation, 100 parts by weight of an acrylic resin solution (trade name: Nikkalite N-3612) manufactured by Nippon Carbide Industries Co., Ltd., Nippon Carbide Industries Co., Ltd. 10.4 parts by weight of red coloring pigment paint (trade name: Nikkalite N-3625) manufactured by Nippon Carbide Industries Co., Ltd. 8 parts by weight of isocyanate-based curing agent (trade name: Nikkalite N-3631) is mixed and stirred to obtain a solid content. About 52% by weight of the UV-excited coloring paint 3 was obtained.

  Next, the ultraviolet excitation coloring paint 3 is screen-printed on a white encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen, and the ultraviolet excitation coloring information display area is displayed. A retroreflective sheet containing was obtained.

Example 4
A 75 μm thick transparent polyethylene terephthalate film (trade name, Teijin Tetron Film S-75) manufactured by Teijin Ltd. was used as a carrier film, and a vinyl chloride resin (trade name, MT-1100 manufactured by Vitec Co., Ltd.) was used thereon. ) In 80 parts by weight, ethylene vinyl acetate resin (trade name, Elvalloy 742) manufactured by Mitsui DuPont Polychemical Co., Ltd. in 16 parts by weight, and acrylic resin (trade name, Hyperl AFR) manufactured in Negami Kogyo Co., Ltd. in 4 parts. Adipic acid polyester plasticizer (trade name, Adeka Sizer PN-400) manufactured by Asahi Denka Kogyo Co., Ltd. is added to 11.7 parts by weight of cellulose derivative (trade name, CAB) manufactured by Eastman Chemical Co., Ltd. 7 parts by weight, 3 parts by weight of Katsuta Kako Co., Ltd. heat stabilizer (trade name, BZ-182LJ) 0.5 parts by weight of an antioxidant (trade name, MG-1500) manufactured by Asahi Denka Kogyo Co., Ltd. and 0.5 parts of an antioxidant (trade name, Irganox 1010) manufactured by Ciba Specialty Chemicals Co., Ltd. The UV absorber (trade name Ubinar 3039) manufactured by BASF Aktiengesellschaft, 1.3 parts by weight, and the UV absorber (trade name Tinuvin 320) manufactured by Ciba Specialty Chemicals Co. To 3 parts by weight, 0.5 parts by weight of a light stabilizer (trade name Tinuvin 770) manufactured by Ciba Specialty Chemicals Co., Ltd. and THF as a solvent were added to make the total solid content 22.5%. After stirring and mixing, the film 1 having a thickness of 55 μm was formed by coating and drying.

In addition, as a release paper, a release paper (trade name: E2P-LPE (P)) manufactured by Lintec Co., Ltd. was used. On top of that, 100 parts by weight of acrylic adhesive (trade name, SK Dyne 1309X), Soken Co., Ltd., Mitsubishi Gas Chemical Co., Ltd. Epoxy crosslinking agent (trade name, Tetrad-X) 0.012 parts by weight and 20 parts by weight of ethyl acetate as a solvent were added and stirred and mixed. The pressure-sensitive adhesive layer was formed.

The film-1 for overlay was prepared by pasting the film-1 previously formed and this pressure-sensitive adhesive layer.

After the overlay film-1 was bonded to the retroreflective sheet including the ultraviolet-excited color information display area prepared in Example 1, S-75, which is a carrier film -1 of the overlay film, was peeled off, and ultraviolet rays were removed. A retroreflective sheet including an excitation color information display area was obtained.

Example 5
A polyethylene terephthalate film is used as a carrier film, on which 100 parts by weight of an acrylic resin solution (trade name, ST-100) manufactured by Special Colorant Co., Ltd. and a methylated melamine resin solution manufactured by Sanwa Chemical Co., Ltd. (product) Name, Nikalac MS-11) 15 parts by weight, Special Colorant Co., Ltd. defoaming agent (trade name, 2570 deformer) 0.5 parts by weight, Special Colorant Co., Ltd. cellulose derivative (trade name, CAB) ) 5 parts by weight, Sipro Kasei Co., Ltd. UV absorber (trade name: Seasorb 704) 0.35 parts by weight, Ciba Specialty Chemicals Co., Ltd. light stabilizer (trade name: Tinuvin 622LD) 0.3 weight Parts, and a catalyst manufactured by Dainippon Ink & Chemicals, Inc. in 0.2 part by weight, MIBK as a solvent 13.7 parts by weight were added so that the ratio of / toluene / IPA = 71/22/7 was added, and the mixture after stirring was applied and dried to form a film-2 having a thickness of 30 μm.

Furthermore, on the film-2, 86 parts by weight of acrylic resin solution (ST-3105) manufactured by Special Colorant Co., Ltd. and 12 isocyanate crosslinking agent (trade name, Sumidur N-75) manufactured by Sumitomo Bayer Urethane Co., Ltd. 43.8 parts by weight of MIBK as a solvent was added to parts by weight, and the mixture obtained by stirring and mixing was applied and dried to form film-3 having a thickness of 55 μm together with film-2.

In addition, as a release paper, a release paper (trade name: E2P-LPE (P)) manufactured by Lintec Co., Ltd. was used. On top of that, 100 parts by weight of acrylic adhesive (trade name, SK Dyne 1309X), Soken Co., Ltd., Mitsubishi Apply and dry an epoxy-based crosslinking agent (trade name, Tetrad-X) manufactured by Gas Chemical Co., Ltd. with 0.012 parts by weight of Tetrad-X and 20 parts by weight of ethyl acetate as a solvent, followed by stirring and mixing. A pressure-sensitive adhesive layer having a thickness of 38 μm was formed.

The film-3 for overlay was formed by pasting the film-3 previously formed and this pressure-sensitive adhesive layer together.

A retroreflective sheet including an ultraviolet-excited color information display area was obtained in the same manner as in Example 4 except that the overlay film-2 was used instead of the overlay film-1 used in Example4.

Example 6
A polyethylene terephthalate film is used as a carrier film, and a polyester resin solution (trade name, ALMATEX HMP-90S) manufactured by Mitsui Chemical Co., Ltd. is added to 50 parts by weight of the polyester resin solution (trade name, ALMA 10 parts by weight of Tex P-110), 40 parts by weight of polyester resin solution (trade name, Olester Q-203) manufactured by Mitsui Chemicals, Ltd., and methylated melamine resin solution (trade name of product manufactured by Sanwa Chemical Co., Ltd.) , Nicarak MS-11) to 11 parts by weight, Mitsui Chemicals Co., Ltd. acrylic resin (trade name, Regix RL-4) to 0.2 parts by weight, Toshiba silicon anti-blocking agent (trade name, TSF4445) to 0 0.005 part by weight, 6 parts by weight of cellulose derivative (trade name, CAB) manufactured by Special Colorant Co., Ltd.・ Specialty Chemicals Co., Ltd. UV absorber (trade name Tinuvin 213) to 0.6 parts by weight, Dainippon Ink & Chemicals Ltd. catalyst trade name (Beccamin P-198) to 0.1 parts by weight, solvent As a result, 25 parts by weight were added so that the ratio of MIBK / toluene / IPA = 66/32/2 was added, and the resulting mixture was applied and dried to form a film-4 having a thickness of 32 μm.

Furthermore, on the film-4, 100 parts by weight of an acrylic resin solution (trade name N-3512) manufactured by Special Colorants Co., Ltd. and a green UV-excited coloring pigment (trade name: Auro Rainbow A160) manufactured by Lintec Co., Ltd. Coloring Co., Ltd. Red colorant (trade name: N-3525) 10.4 parts by weight, 83 parts by weight of MIBK as a solvent and stirring and mixing are printed on a gravure printing machine, and UV-excited color development An information display area was formed.

Further, toluene / MIBK (1/1) of MMA / EA / 2HEMA copolymer (weight ratio: MMA / EA / 2HEMA = 21/65/14) is formed on the film-4 on which the ultraviolet excitation color information display area is formed. ) 100 parts by weight of the solution (solid content = 40%), 8 parts by weight of an isocyanate-based crosslinking agent (trade name, Sumidur N-75) manufactured by Sumitomo Bayer Urethane Co., Ltd., and MIBK / toluene / high boiling solvent ( New Nippon Petrochemical Co., Ltd., trade name Supersol 1500) = 35.8 parts by weight so as to have a ratio of 39/16/45, and the mixture that was stirred and mixed was applied, dried, and combined with film-4. A film-5 having a thickness of 63 μm was formed.

Further, glass beads (trade name: UNIBEADS N-34S) manufactured by Union Bead Co., Ltd. were sprayed on the film-5, and then dried and cured.
Furthermore, toluene / xylene / ethyl acetate / n-butanol (11/45/29/15) of MMA / BA / AA copolymer (weight ratio: MMA / BA / AA = 35/50/15) on the beads. 100 parts by weight of the solution (solid content = 30%), 5.5 parts by weight of a methylated melamine resin solution (trade name, Nicalac MS-11) manufactured by Sanwa Chemical Co., Ltd. and MIBK / toluene = 2/3 as a solvent 39.3 parts by weight were added so that the ratio of the mixture was stirred and mixed, and dried to form a film-6.

Furthermore, aluminum was vacuum-deposited on the film-6 to form a film-7.

In addition, as a release paper, a release paper (trade name E2AP-LK-BL (P)) manufactured by Lintec Corporation is used, and a BA / AA copolymer (weight ratio: BA / AA = 90/10) is further formed thereon. To 100 parts by weight of an ethyl acetate / toluene (1/1) solution (solid content = 34%), to 9 parts by weight of a white colorant (trade name: AR-9127W) manufactured by Special Colorant Co., Ltd., manufactured by Nippon Polyurethane Industry Co., Ltd. Add 17.8 parts by weight of an isocyanate-based crosslinking agent (trade name, Coronate L) and 17.8 parts by weight of ethyl acetate as a solvent, and stir and mix to dry and form a 40 μm thick adhesive layer did.

The film-7 previously formed and this pressure-sensitive adhesive layer were bonded together, and then the carrier film was peeled off to obtain a retroreflective sheet including an ultraviolet-excited color information display area.

Example 7
2 parts by weight of green UV-excited coloring pigment (trade name: Aurora Rainbow A160) manufactured by Lintec Corporation, 100 parts by weight of acrylic resin solution (trade name: Nikkalite N-3612) manufactured by Nippon Carbide Industry Co., Ltd., Nippon Carbide Industries Co., Ltd. 8 parts by weight of an isocyanate-based curing agent (trade name: Nickarite N-3631) manufactured by mixing was mixed and stirred to obtain an ultraviolet-excited coloring paint 4 having a solid content of about 38% by weight.

Next, the ultraviolet excitation coloring paint 4 is screen-printed on a blue encapsulated retroreflective sheet (trade name: Nikkalite EG 8106) manufactured by Nippon Carbide Industries Co., Ltd. using a 180-mesh screen, and the ultraviolet excitation coloring information display area is displayed. A retroreflective sheet containing was obtained.

Example 8
In Example 1, instead of the blue encapsulated retroreflective sheet, a red encapsulated retroreflective sheet (trade name: Nikkalite EG 8105) manufactured by Nippon Carbide Industries Co., Ltd. was used to obtain an ultraviolet-excited coloring retroreflective sheet. In the same manner as in Example 1, a retroreflective sheet including an ultraviolet-excited color information display area was obtained.

Example 9
2 parts by weight of blue UV-excited coloring pigment (trade name: Aurora Rainbow A180) manufactured by Lintec Corporation, 100 parts by weight of acrylic resin solution (trade name: Nikkalite N-3612) manufactured by Nippon Carbide Industry Co., Ltd., Nippon Carbide Industries Co., Ltd. 8 parts by weight of an isocyanate-based curing agent (trade name: Nickarite N-3631) manufactured by mixing was stirred to obtain an ultraviolet-excited color-coating material 5 having a solid content of about 38% by weight.

Next, the ultraviolet excitation coloring paint 5 is screen-printed on a yellow encapsulated retroreflective sheet (trade name: Nikkalite EG 8104) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen, and an ultraviolet excitation coloring information display area is displayed. A retroreflective sheet containing was obtained.

Example 10
34 parts by weight of green UV-excited coloring pigment (trade name: Aurora Rainbow A160) manufactured by Lintec Corporation, 100 parts by weight of an acrylic resin solution (trade name: Nikkalite N-3612) manufactured by Nippon Carbide Industries Co., Ltd., Nippon Carbide Industries Co., Ltd. 10.4 parts by weight of red coloring pigment paint (trade name: Nikkalite N-3625) manufactured by Nippon Carbide Industries Co., Ltd. 8 parts by weight of isocyanate-based curing agent (trade name: Nikkalite N-3631) is mixed and stirred to obtain a solid content. About 52% by weight of the UV-excited coloring paint 6 was obtained.

  Next, the ultraviolet excitation coloring paint 6 is screen-printed on a white encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen, and the ultraviolet excitation coloring retroreflective sheet. Got.

  Furthermore, Nippon Carbide Industries Co., Ltd. white colored pigment (trade name Nikkalite N-3601) 100 parts by weight, Nippon Carbide Industries Co., Ltd. red color pigment paint (trade name Nikkalite N-3625) 15.6 parts by weight, Japan 8 parts by weight of an isocyanate-based curing agent (trade name: Nikkalite N-3631) manufactured by Carbide Industries Co., Ltd. was mixed and stirred to obtain a red paint 1 having a solid content of about 48% by weight.

  The obtained red paint 1 was printed on the non-information display area portion of the ultraviolet light emitting retroreflective sheet using a 180 mesh screen to obtain a multicolor retroreflective sheet including the ultraviolet light excitation coloring information display area.

Comparative Example 1
An encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries Co., Ltd., to which no UV-excited coloring paint was applied, was evaluated.

Comparative Example 2
Nippon Carbide Industries Co., Ltd. white coloring pigment paint (trade name: Nikkalite N-3601) 100 parts by weight, Nippon Carbide Industry Co., Ltd. isocyanate-based curing agent (trade name: Nikkalite N-3631) 8 parts by weight are mixed and stirred. Thus, a white paint 1 having a solid content of about 50% by weight was obtained.

  The obtained white paint 1 is screen-printed on an encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries, Ltd. using a 180 mesh screen to obtain a retroreflective sheet including an information display area. It was.

Comparative Example 3
Nippon Carbide Industries Co., Ltd. white colored pigment paint (trade name: Nikkalite N-3601) 100 parts by weight, Nippon Carbide Industries Co., Ltd. red color pigment paint (trade name: Nikkalite N-3625) 7.4 parts by weight, 8 parts by weight of an isocyanate-based curing agent (trade name: Nikkalite N-3631) manufactured by Nippon Carbide Industries Co., Ltd. was mixed and stirred to obtain a red paint 2 having a solid content of about 49% by weight.

  The obtained red paint 2 is screen-printed on an encapsulated retroreflective sheet (trade name: Nikkalite EG 8112) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen to obtain a retroreflective sheet including an information display area. It was.

Comparative Example 4
In Comparative Example 2, an information region was included in the same manner as in Comparative Example 2 except that 100 parts by weight of a red colored pigment paint (trade name: Nikkalite N-3625) manufactured by Nippon Carbide Industries Co., Ltd. was used instead of the white pigment paint. A retroreflective sheet was obtained.

Comparative Example 5
In Comparative Example 2, an information region was included in the same manner as in Comparative Example 2 except that 100 parts by weight of a blue colored pigment paint (trade name: Nikkalite N-3616) manufactured by Nippon Carbide Industries Co., Ltd. was used instead of the white pigment paint. A retroreflective sheet was obtained.

Comparative Example 6
In Comparative Example 2, an information region is included in the same manner as in Comparative Example 2 except that 100 parts by weight of a green colored pigment paint (trade name: Nikkalite N-3608) manufactured by Nippon Carbide Industries Co., Ltd. was used instead of the white pigment paint. A retroreflective sheet was obtained.

Comparative Example 7
A commercially available encapsulated fluorescent retroreflective sheet (trade name: Nikkalite MPG F4394) manufactured by Nippon Carbide Industries Co., Ltd. was evaluated.

Comparative Example 8
A commercially available encapsulated fluorescent retroreflective sheet (trade name: Nikkalite SEG 15947) manufactured by Nippon Carbide Industries Co., Ltd. was evaluated.

Comparative Example 9
A commercially available prism-type fluorescent retroreflective sheet (trade name: Nikkalite CRG 92844) manufactured by Nippon Carbide Industries Co., Ltd. was evaluated.

Comparative Example 10
A commercially available prism-type fluorescent retroreflective sheet (trade name: Nikkalite CRG 92847) manufactured by Nippon Carbide Industries Co., Ltd. was evaluated.

Comparative Example 11
Nippon Carbide Industries Co., Ltd. white colored pigment paint (trade name: Nikkalite N-3601) 1 part by weight, Nippon Carbide Industries Co., Ltd. acrylic resin solution (trade name: Nikkalite N-3612) 100 parts by weight, Nippon Carbide 8 parts by weight of an isocyanate curing agent (trade name: Nikkalite N-3631) manufactured by Kogyo Co., Ltd. was mixed and stirred to obtain a white paint 2 having a solid content of about 37% by weight.

Next, the white paint 2 is screen-printed on an encapsulated yellow retroreflective sheet (trade name: Nikkalite EG 8104) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen, and a retroreflective sheet including an information display area is obtained. Obtained.

Comparative Example 12
Nippon Carbide Industries Co., Ltd. yellow colored pigment paint (trade name Nikkalite AR-2019) 75 parts by weight, Nippon Carbide Industries Co., Ltd. green color pigment paint (trade name Nikkalite AR-2001) 25 parts by weight, Nippon Carbide 10 parts by weight of a white color pigment paint (trade name: Nikkalite N-3601) manufactured by Kogyo Co., Ltd. and 8 parts by weight of an isocyanate-based curing agent (trade name: Nikkalite N-3631) manufactured by Nippon Carbide Industries Co., Ltd. were mixed and stirred. A yellow paint 1 having a solid content of about 37% by weight was obtained.

  Next, yellow paint 1 was screen-printed on an encapsulated retroreflective sheet (trade name: Nikkalite MPG F4312) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen to obtain a yellow retroreflective sheet.

  Next, the release paper of the encapsulated fluorescent retroreflective sheet (trade name: Nikkalite MPG F4394) manufactured by Nippon Carbide Industries, Ltd. was peeled off and laminated on the yellow retroreflective sheet to obtain a retroreflective sheet including an information area.

Comparative Example 13
Nippon Carbide Industries Co., Ltd. yellow-red colored pigment paint (trade name Nikkalite N-3607) 100 parts by weight, Nippon Carbide Industries Co., Ltd. white color pigment paint (trade name Nikkalite N-3601) 4 parts by weight, Japan 8 parts by weight of an isocyanate-based curing agent (trade name: Nikkalite N-3631) manufactured by Carbide Industries Co., Ltd. was mixed and stirred to obtain a yellowish red paint 1 having a solid content of about 37% by weight.

  Next, the yellow-red paint 1 was screen-printed on an encapsulated retroreflective sheet (trade name: Nikkalite SEG 18012) manufactured by Nippon Carbide Industries Co., Ltd. using a 180 mesh screen to obtain a yellow-red retroreflective sheet.

  Next, the release paper of the encapsulated fluorescent retroreflective sheet (product name: Nikkalite SEG 15947) manufactured by Nippon Carbide Industries, Ltd. was peeled off and laminated on the yellow-red retroreflective sheet to obtain a retroreflective sheet including an information area. .

Using the retroreflective sheets of Examples 1 to 6 and Comparative Examples 1 to 10 as test samples, colorimetry using a D65 light source and chromaticity values using a D65 light source including additional ultraviolet light were measured.

The results are shown in Table 1.

Further, using the retroreflective sheets of Examples 1 to 6 and Comparative Examples 1 to 10 as test samples, visual recognition due to changes in color and light source when a D65 light source and a D65 light source including additional ultraviolet light are alternately applied. The change in sex was visually evaluated.

The results are shown in Table 2.

Using the retroreflective sheets of Examples 7 to 10 as test samples, the D65 light source is used to measure the colorimetry and chromaticity difference between the UV-excited color information display area, the information display area other than the UV-excited color area, and the non-information display area. did.

The results are shown in Table 3.

Using the retroreflective sheets of Examples 7 to 10 and Comparative Examples 11 to 13 as test samples, the D65 light source was used to measure the color of the information display area and the non-information display area other than ultraviolet excitation coloring.

The results are shown in Table 4.

Further, using the retroreflective sheets of Examples 7 to 10 and Comparative Examples 11 to 13 as test samples, changes in visibility due to changes in the light source when the D65 light source and the D65 light source including additional ultraviolet light are alternately applied. Visual evaluation was performed.

The results are shown in Table 5.

It is sectional drawing of a capsule-type triangular pyramid cube corner retroreflection sheet. It is sectional drawing of a vapor deposition type triangular pyramidal cube corner retroreflection sheet. It is sectional drawing of a capsule lens type retroreflection sheet. It is sectional drawing of an enclosure lens type retroreflection sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface protective layer 2 Printing layer 3 Holding body layer 4 Retroreflective element layer 5 Holding body layer + retroreflective element layer integral 6 Air layer 7 Binder layer 8 Support body layer 9 Adhesive layer 10 Peeling base material layer 11 Specular reflection layer 21 Surface protective layer 22 Print layer 23 Retroreflective element 24 Binder layer 25 Bonding portion 26 Support layer 27 Specular reflection layer 28 Air layer 31 Surface protective layer 32 Print layer 33 Transparent microsphere 34 Bead binding layer 35 Focus adjustment layer 36 Mirror surface Reflection layer 40 Light incident direction

Claims (10)

In the retroreflective sheet including the information display area, the information display area includes an ultraviolet-excited coloring layer formed from a colorant composition that is colored by being excited by ultraviolet rays, and the ultraviolet-excited coloring area is L ^* a using a D65 light source. ^* B ^* Color values measured in the color system (L ₁ ^* , a ₁ ^* , b ₁ ^* ), and color values (L ₂₎ measured using the D65 light source and additional ultraviolet light in the ultraviolet excitation coloring region. ^* , A ₂ ^* , b ₂ ^* ), the hue difference index ΔS ^* represented by the following formula (1) is 14 or more, and the retroreflective sheet.
ΔS ^* = ((a ₂ ^* −a ₁ ^* ) ² + (b ₂ ^* −b ₁ ^* ) ² ) ^1/2 ... (1) When an area of the retroreflective sheet where information is not displayed (hereinafter referred to as a non-information display area) is a colorimetric value (L ₃ ^* , a ₃ ^* , b ₃ ^* ) measured using a D65 light source, the following formula The color difference ΔE ^* ₁ represented by (2) or the color display value (L ₄ ^* , a ₄ ^* , b ₄ ^* ) measured using the D65 light source other than the ultraviolet excitation color development area The retroreflective sheet according to claim 1, wherein the color difference ΔE ^* ₂ sometimes represented by the following formula (3) is 5 or less.
ΔE ₁ ^* = ((L ₃ ^* −L ₁ ^* ) ² + (a ₃ ^* −a ₁ ^* ) ² + (b ₃ ^* −b ₁ ^* ) ² ) ^1/2 ... (2)
ΔE ₂ ^* = ((L ₄ ^* −L ₁ ^* ) ² + (a ₄ ^* −a ₁ ^* ) ² + (b ₄ ^* −b ₁ ^* ) ² ) ^1/2 ... (3) The retroreflective sheet according to claim 2, wherein ΔE ₁ ^* and / or ΔE ₂ ^* is 2 or less. The retroreflective sheet is any one of an open lens type retroreflective sheet, an encapsulated lens type retroreflective sheet, a capsule lens type retroreflective sheet, and a cube corner type retroreflective sheet. The retroreflective sheet described in 1. The retroreflective sheet according to any one of claims 1 to 4, wherein the information display area has retroreflectivity. The colorant composition that develops color when excited by ultraviolet rays can effectively produce color when a black light with a center wavelength of 352 nm is applied, and is effective when a black light with a center wavelength of 368 nm is applied. The retroreflective sheet according to any one of claims 1 to 5, wherein color development is not obtained. The retroreflective sheet has a UV-absorbing color layer and / or a UV-absorbing UV-absorbing layer on the light incident side of the UV-exciting color layer, and the UV-absorbing layer has a UV absorption rate of 75% at a wavelength of 360 nm. The retroreflective sheet according to claim 1, wherein the retroreflective sheet is as follows. The retroreflective sheet according to claim 1, wherein the information display area is formed of two or more colors. The retroreflective sheet according to any one of claims 1 to 8, wherein the hue, brightness, and saturation of the information display area change in gradation (gradation). A license plate in which the reflective sheet according to any one of claims 1 to 9 is laminated on aluminum or a steel plate, or a light incident side of a retroreflective sheet is laminated on a transparent resin plate via an adhesive layer.