JP6516550B2 - Retroreflective sheet - Google Patents

Description

  The present invention relates to a retroreflective sheet.

  Retroreflective sheets that retroreflect incident light toward a light source are widely used in marking boards such as road signs, construction signs, and vehicle license plates. Then, in the marking board, a color different from the color of the appearance of the retroreflective sheet serving as the background of the marking board is given to the marking information such as characters and numbers.

  As a retroreflective sheet used for such a marking plate, a vapor deposition type cube corner retroreflective sheet is known. This vapor deposition type cube corner retroreflective sheet is affected by the metallic color of the specular reflection layer to make the appearance of the retroreflective sheet dark, and when it is used for a marking plate, it is difficult to read marking information in the daytime, and improvement of brightness is required It is done.

  Therefore, in order to improve the lightness, the applicant of the present invention has proposed a vapor deposition type triangular pyramid cube corner retroreflective sheet described in Patent Document 1 below. This vapor deposition type triangular pyramid cube corner retroreflective sheet comprises a reflective element layer comprising a large number of reflective elements and a holder layer, a surface protection layer provided at the interface of the reflective element layer on the holder layer side, and a reflective element It has a specular reflection layer installed at the interface of the layer on the side of the reflection element portion, and between the surface protective layer and the reflection element layer, colored printing is performed with a predetermined pattern (repetitive pattern) to improve the lightness. It has a layer.

JP, 2001-290013, A

  Although the retroreflective sheet of Patent Document 1 has improved lightness, the colored print layer is provided in a predetermined pattern, so that color unevenness occurs in the appearance of the sheet. Therefore, when such a retroreflective sheet is used for a marking plate, the background color of the marking plate becomes nonuniform, which may cause a problem that it is difficult to read the marking information provided on the background.

  Then, this invention is made in order to solve the said subject, It is an object of this invention to provide the retroreflective sheet which was excellent in the brightness and suppressed the color nonuniformity of an external appearance in a vapor deposition type retroreflective sheet.

  The retroreflective sheet of the present invention has a first surface on which light is incident, and a second surface on which a metal layer is formed, and transmits light which retroreflects light incident from the first surface on the second surface. Retroreflective layer, an opaque first colored layer provided on the first surface in a state of partially covering the first surface in a predetermined pattern, and the first surface of the first surface It is provided on an uneven surface comprising a portion where the colored layer is not provided and a portion of the surface of the first colored layer not in contact with the retroreflective layer, and has a lower total light transmittance than the retroreflective layer. And a light transmitting second colored layer, wherein the second colored layer is formed to follow the uneven surface.

  In such a retroreflective sheet, the second colored layer is formed to follow the first colored layer, so that the surface of the second colored layer is the first colored layer in the gap between the adjacent first colored layers. Along the uneven surface consisting of and the first surface. Therefore, in the gap, the portion of the second colored layer located in the vicinity of the outline portion of the first colored layer is thicker than the portion of the second colored layer located in the vicinity of the central portion of the gap. The color can be progressively lighter from the contour of the to the center of the gap. Therefore, since the change of the lightness and darkness changes with respect to the lightness and darkness difference between the color of the first colored layer and the color of the metal layer, which causes color unevenness of appearance, the color unevenness of appearance can be reduced. Therefore, in the retroreflective sheet of the present invention, even if the first colored layer is provided in a predetermined pattern, the second colored layer can suppress color unevenness of the appearance in order to improve the lightness. Then, when the retroreflective sheet of the present invention is used for a marking plate, the lightness of the marking plate can be sufficiently secured, and marking information can be easily read.

  The thickness of the second colored layer is preferably smaller than the thickness of the first colored layer.

  In the light transmitting colored layer, it is difficult to uniformly control the thickness of the layer and the concentration of the colorant, so it is difficult to make the same color over the entire area of the colored layer. Therefore, even in the second colored layer, due to the variation in the thickness of the layer and the concentration of the colorant, the variation in color is caused to some extent. And when a 2nd colored layer is formed thinner than a 1st colored layer, since the variation in thickness becomes large further, the 2nd colored layer will be mixed with various colors of the same type | system | group. Therefore, in each gap between adjacent first colored layers, the second colored layer not only makes the change of the density moderate with respect to the density difference between the color of the first colored layer and the color of the metal layer. The degree of change or change of the density can be made different for each gap. And the color nonuniformity of an external appearance can be suppressed further by the visual effect which arises by it. Therefore, when the retroreflective sheet of the present invention is used for a marking plate, the lightness of the marking plate can be sufficiently secured, and marking information can be read more easily.

  As described above, according to the present invention, it is possible to provide a vapor deposition-type retroreflective sheet having excellent lightness and suppressing color unevenness of the appearance.

It is a figure which shows the appearance of the cross section of the retroreflective sheet in 1st Embodiment. It is a figure which shows the mode at the time of seeing the 1st surface of the retroreflective sheet in 1st Embodiment from a front. It is a figure which expands and shows the mode of the cross section of the retroreflective sheet in 1st Embodiment.

  In the present specification, “color unevenness” means that on a surface of a sheet, shades of color differ depending on portions, and the color of the surface is not uniform. Furthermore, in the present specification, “the thickness of the first colored layer” refers to the upper surface (approximately flat surface) of the first colored layer from the first surface of the retroreflective layer in the cross section in the thickness direction of the retroreflective sheet Means the distance to part). Furthermore, in the present specification, “the thickness of the second colored layer” is the thickness of a portion in contact with the first surface of the retroreflective layer in the cross section in the thickness direction of the retroreflective sheet, It means the distance from the surface to the upper surface (portion corresponding to a substantially flat surface) of the second colored layer. In addition, each thickness of each layer is taken as the thickness which measured the thickness of the applicable part in 10 arbitrary positions of a retroreflective sheet, and was arithmetically averaged.

  A first embodiment suitable for the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a retroreflective sheet in the first embodiment. As shown in FIG. 1, the retroreflective sheet 1 in the present embodiment mainly includes a retroreflective layer 10, a first colored layer 20, a second colored layer 30, a surface protective layer 40, a metal layer 50 and an adhesive layer 60. It has as a component.

  The retroreflective layer 10 has a first surface 11 on which light is incident and a second surface 12 on which the metal layer 50 is formed, and light which retroreflects light incident from the first surface 11 on the second surface 12 It is a permeable layer.

  The retroreflective layer 10, as shown in FIG. 1, is a layer comprising a cube-corner reflective element portion and a holder layer portion for holding a plurality of reflective element portions. In addition, when reflective element parts, such as a triangular pyramid and a hexagonal pyramid, are formed in close-packed shape and the retroreflective layer 10 is employ | adopted, since reflective performance is excellent, it is preferable. Such a retroreflective layer 10 is disclosed, for example, in Japanese Patent Application Laid-Open No. 2008-70898.

  As a material of such a retroreflective layer 10, a material excellent in optical characteristics is preferable. For example, polycarbonate resin, vinyl chloride resin, vinylidene fluoride resin, acrylic resin, epoxy resin, styrene resin, polyester resin, fluorine resin, polyethylene resin, olefin resin, cellulose resin, urethane Examples include resin-based resins.

  Further, the retroreflective layer 10 covers a plurality of micro glass spheres, a holding layer for holding the plurality of glass spheres in a state of exposing a part of each micro glass sphere, and a state of covering the micro glass spheres exposed from the holding layer. And the focusing layer may be laminated on the holding layer to adjust the focal position of the micro glass spheres. In this case, the surface opposite to the focal layer side of the holding layer is the first surface, and the surface opposite to the holding layer side of the focal layer is the second surface. Such a retroreflective layer 10 is disclosed, for example, in JP-A-59-71848.

  The first colored layer 20 is provided on the first surface 11 of the retroreflective layer in a predetermined pattern, and is a light impermeable layer that does not transmit visible light. The first colored layer 20 is preferably formed by printing. The material of the first colored layer 20 may be any of various components such as a plasticizer, an antifoaming agent, a leveling agent, an ultraviolet light absorber, a light stabilizer, a heat stabilizer, and a crosslinking agent, in addition to the resin component and the colorant. Additives may be blended, and a solvent may be blended for viscosity adjustment and the like.

  Among the materials of the first colored layer 20, the resin component is not particularly limited, but the dispersibility and stability of the coloring agent, solubility in a solvent, weatherability, printability, adhesion to a film, etc. And melamine resins, epoxy resins, urethane resins, vinyl resins, polyester resins, alkyd resins, acrylic resins, etc., and those obtained by copolymerizing these alone or in combination of two or more can be used.

  Although it does not specifically limit as a coloring agent among the materials of the 1st colored layer 20, A white organic pigment, an inorganic pigment, etc. are mentioned. Examples of white inorganic pigments include titanium oxide, calcium carbonate, barium sulfate, zinc oxide, zinc sulfide and the like.

  FIG. 2 is a view showing the first surface 11 of the retroreflective sheeting in the first embodiment as viewed from the front. The first colored layer 20 in FIG. 2 is hatched for easy understanding. As shown in FIG. 2, the first colored layer 20 partially covers the first surface 11 of the retroreflective layer 10 with a predetermined pattern, and is configured of a plurality of independent regions.

  In addition, although the shape of the area | region which comprises the 1st colored layer 20 is circular shape in the example of FIG. 2, the shape of the whole or one part of the area | region which comprises the said 1st colored layer 20 may be rectangular shape etc. You may change into various shapes, such as trapezoid shape. Moreover, although the magnitude | size of each area | region which comprises the 1st colored layer 20 is the same in the example of FIG. 2, you may differ. Furthermore, in the example of FIG. 2, the regions constituting the first colored layer 20 are arranged along the row direction and the column direction at predetermined intervals, but the regions constituting the first colored layer 20 are random. It may be arranged in Moreover, although the 1st colored layer 20 is comprised by the some independent area | region, the 1st colored layer 20 may partition the several independent area | region.

  Further, the ratio of the area of the first colored layer 20 to the area of the first surface 11 in the retroreflective layer 10 is not particularly limited, but is preferably 50% to 80%. The area of the first colored layer 20 is the sum of the areas of the portions of the first surface 11 of the retroreflective layer 10 covered by the respective regions constituting the first colored layer 20. When the ratio is 50% or more, the brightness of the retroreflective sheet can be further improved. In addition, when the ratio is 80% or less, it becomes easy to obtain desired retroreflective performance

  The second colored layer 30 is a light transmitting layer that transmits visible light, and has a lower total light transmittance than the retroreflective layer 10. In addition, the second colored layer 30 has an uneven shape including a portion of the first surface 11 where the first colored layer 20 is not provided and a portion of the surface of the first colored layer 20 which is not in contact with the retroreflective layer 10. It is provided on the entire surface of the uneven surface so as to follow the surface. In addition, the thickness of the second colored layer 30 is smaller than the thickness of the first colored layer 10. Furthermore, the surface of the second colored layer 30 on the opposite side to the retroreflective layer 10 is undulated along the uneven surface in substantially the same shape as the uneven surface.

  As a material of the second colored layer 30, for example, in addition to the resin component and the colorant, if necessary, a plasticizer, an antifoamer, a leveling agent, an ultraviolet light absorber, a light stabilizer, a heat stabilizer, a crosslinking agent And other additives may be blended, and a solvent may be blended for viscosity adjustment and the like.

  The resin component in the material of the second colored layer 30 is not particularly limited, but the dispersibility and stability of the colorant, solubility in a solvent, weatherability, printability, adhesion to a film, etc. Melamine resin, epoxy resin, urethane resin, vinyl resin, polyester resin, alkyd resin, acrylic resin, polyolefin resin which is a crystalline resin, nylon resin, etc. are mentioned, and these are copolymerized alone or in combination of two or more kinds. You can use one.

  Although it does not specifically limit as a coloring agent among the materials of the 2nd colored layer 30, A white organic pigment, a white inorganic pigment, etc. are mentioned. Examples of white inorganic pigments include titanium oxide, calcium carbonate, barium sulfate, zinc oxide, zinc sulfide and the like.

  Moreover, it is preferable that the color of the 2nd colored layer 30 is a system color similar to the 1st colored layer 20 from a viewpoint of suppressing the color nonuniformity of an appearance further. In order to make the first colored layer 20 and the second colored layer 30 have the same color, the same coloring agent as the first colored layer 20 is used as the coloring agent for the second colored layer 30, and the second colored layer is used. The same color can be obtained by making the concentration of the colorant of T.30 thinner than that of the first colored layer.

  The ratio of the total light transmittance of the second colored layer 30 to the total light transmittance of the retroreflective layer 10 is not particularly limited, but is preferably 70% or more and 90% or less. When the ratio is 70% or more, the difference in density between the color of the first colored layer 20 and the color of the metal layer 50 becomes smaller, and color unevenness of the appearance can be further suppressed. In addition, when the ratio is 90% or less, desired retroreflective performance can be easily obtained. The total light transmittance of the second colored layer 30 can be adjusted by changing the content of the colorant.

  The surface protective layer 40 is a light transmitting layer disposed on the outermost side in the thickness direction of the retroreflective sheet. As a material of this surface protection layer 40, the thing similar to the retroreflective layer 10 is mentioned, for example.

  The metal layer 50 is a layer provided on the second surface 12 of the retroreflective layer 10. As a material of this metal layer 50, metals, such as aluminum, copper, silver, nickel, are mentioned, for example.

  The pressure-sensitive adhesive layer 60 is provided on the other side of the metal layer 50 opposite to the side facing the retroreflective layer 10. Examples of the material of the pressure-sensitive adhesive layer 60 include acrylic resins, epoxy resins, phenol resins, vinyl acetate resins, nitrile rubber resins, silicone rubber resins, and the like.

  In addition, when the retroreflective sheet 1 is not in use, the release layer 70 is provided on the other side of the pressure-sensitive adhesive layer 60 opposite to the side facing the metal layer 50, and the pressure-sensitive adhesive layer 60 Prevent the adhesion of dust etc. On the other hand, when the retroreflective sheet 1 is used, the peeling layer 70 is peeled from the pressure-sensitive adhesive layer 60 in order to be attached to an adherend such as a marking plate.

  FIG. 3 is an enlarged view of a part of the cross section of the retroreflective sheet in the first embodiment. In the present embodiment, as shown in FIG. 3, in the second colored layer 30 provided in the gap between the adjacent first colored layers 20, the second colored layer 30 of the portion provided in the vicinity of the outline portion of the first colored layer 20. Is thicker than the second colored layer in a portion provided near the center of the gap. Due to the change in thickness, the color of the second colored layer 30 gradually becomes lighter from the outline of the first colored layer 20 to the center of the gap. As a result, with respect to the color density difference that causes the color unevenness of the appearance, it is possible to moderate the change of the density, and as a result, the color unevenness of the appearance can be suppressed. Therefore, the appearance of the retroreflective sheet 1 in the first embodiment can be made more uniform than in the prior art, so that color unevenness of the appearance can be suppressed. And when retroreflective sheet 1 in a 1st embodiment is used for a marking board, the lightness of a marking board can fully be secured and marking information can be made easy to read.

  Moreover, in the present embodiment, the second colored layer 30 is formed thinner than the first colored layer 20. In this case, since the variation in the thickness of the second colored layer 30 is further increased, various colors of the second color layer 30 are mixed. Therefore, in each gap between adjacent first colored layers 20, the second colored layer 30 moderates the change of the density to the density difference between the color of the first colored layer 20 and the color of the metal layer. Not only that, it is possible to make the degree of change of the density and the method of change different for each gap. And the color nonuniformity of an external appearance can be suppressed further by the visual effect which arises by it. Therefore, when the retroreflective sheet 1 in the first embodiment is used as a marking plate, the brightness of the marking plate can be sufficiently ensured, and the marking information can be read more easily.

1 ... retroreflective sheet 10 ... retroreflective layer 11 ... first surface 12 ... second surface 20 ... first colored layer 30 ... second colored layer 40 ... surface protection Layer 50: Metal layer 60: Adhesive layer 70: Peeling layer

Claims (1)

A light transmitting retroreflective layer having a first surface on which light is incident and a second surface on which a metal layer is formed, and retroreflectively reflecting light incident from the first surface on the second surface;
A light-impermeable first colored layer provided on the first surface in a state of partially covering the first surface in a predetermined pattern;
It is provided on an uneven surface comprising a portion of the first surface where the first colored layer is not provided and a portion of the surface of the first colored layer which is not in contact with the retroreflective layer, and the retroreflection A light transmitting second colored layer having a total light transmittance lower than that of the layer;
Equipped with
The second colored layer is formed following the uneven surface ,
The thickness of the second colored layer is smaller than the thickness of the first colored layer,
The surface of the second colored layer opposite to the retroreflective layer side is undulated in substantially the same shape as the uneven surface along the uneven surface. Reflective sheet.

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