HK1094620B

HK1094620B - Retroreflective sheet for security and method for manufacturing the same

Info

Publication number: HK1094620B
Application number: HK07101454.0A
Authority: HK
Inventors: 汤川重男; 田中雅宣
Original assignee: 纪和化学工业株式会社
Priority date: 2003-11-14
Filing date: 2004-11-12
Publication date: 2009-05-29

Description

Retroreflective sheet for security and method for producing the same

Technical Field

The present invention relates to retroreflective sheeting for security and a method of manufacturing the same.

Background

Currently, a vehicle officially registered in any country in the world is given a unique number and is installed in the front and rear of the vehicle in the form of a license plate. However, in recent years, a car theft event often occurs, and since the license plate of the stolen car is replaced by the license plate of another car, the stolen car is difficult to reveal. And at present, only the license plate is stolen and the case of criminal behavior is used in the theft is also increased.

In order to solve such problems, a method of attaching vehicle information and a sticker having an anti-counterfeit function to a rear window in a vehicle has been proposed. As a label to be attached to the inside of a transparent object to be attached and viewed from the outside, for example, there has been proposed a tamper-proof label for a vehicle logo including a printed layer for displaying vehicle information such as character information and a barcode and a self-destructing layer including a hologram and the like formed on the printed layer (see, for example, patent document 1). The vehicle logo label is characterized in that a pressure-sensitive adhesive layer is provided on the self-destructing layer side, and the label is stuck to an object to be stuck via the pressure-sensitive adhesive layer. Thus, if the vehicle logo label once attached is peeled off, the self-destructing layer is destroyed, and thus the label cannot be reused.

As a label to be attached to the inside of the transparent object to be attached and viewed from the outside, a hologram label for internal attachment formed by laminating a transparent adhesive layer, a hologram layer, and a light transmission-inhibiting layer is known (for example, see patent document 2). The light transmission inhibiting layer is dark color to improve visual contrast of the holographic image and inhibit visible light from projecting onto the back of the holographic image layer. Therefore, the hologram image layer is visually easily recognized with the light transmission suppressing layer as a background when viewed from the side of the transparent adhesive layer attached to the attachment object. As the light transmission suppressing layer, a plastic film or the like which is appropriately colored with a dye or a pigment can be used.

However, the vehicle logo label of patent document 1 has a self-destructing layer, a printing layer containing character information and the like, and a support layer in this order as viewed from the side of the object to which the label is attached. Therefore, in the attached state, if the support layer is removed by an arbitrary method, the printed layer may be reached. Therefore, there is a problem that the label can be not peeled off and the label can be forged from the inner surface side by removing the printed layer, changing the character information with a tool such as a marker, and then newly forming another printed layer.

In the vehicle logo label of patent document 1, even if the printed layer is formed on the self-destructing film in order to avoid the above-mentioned problem, the authentication pattern such as a hologram image as the self-destructing layer is hidden by the printed layer when viewed from the side of the object to be adhered, and therefore, there is a problem that it is difficult to recognize the authentication pattern. As described above, it is difficult to distinguish the label having the printed layer containing the counterfeit character information from the vehicle logo label of patent document 1 from the side of the object to be attached, and therefore, it is highly likely that the counterfeit label can be easily used.

The hologram label for inner sticking to be stuck to a sticking object of patent document 2 has a transparent adhesive layer, a hologram image layer, and a light transmission suppressing layer in this order as viewed from the sticking object side. Therefore, patent document 2 does not describe the content of forming an image such as text information, and even if an image is formed, the image cannot be seen clearly because a dark light transmission suppression layer is used as a background.

As the label attaching object described in patent documents 1 and 2, there are colored glasses such as automobile smoke glass, and glasses such as a colored heat ray-blocking film and a metal-deposited film are bonded. The problems are that: when the label attached to the object is viewed from the side of the object, the image printed on the label cannot be clearly recognized by the glass, and the authentication pattern of the hologram image layer is hardly recognized. Even if the printed surface of the label pasted on the glass is irradiated with light from the pasting object side, the glass or the like obstructs the transmission of light, and it is very difficult to recognize the image on the printed surface of the label.

Further, as a decorative retroreflective sheet, a plurality of transparent balls are embedded in the surface of a transparent fixing layer, and a translucent portion in which the transparent balls are not provided is provided in a part of the retroreflective sheet on the fixing layer (see, for example, reference 3). In the case where a direct reflection layer is provided on the back surface of the transparent ball, and in the case where no reflection layer is provided, the portion where the transparent ball is not provided is a light-transmitting portion, and is designed to transmit light. The manufacturing method comprises printing the zonal line part K on the surface of the temporary fixing layer, embedding the transparent ball into the part except the zonal line part K on the surface of the temporary fixing layer, forming a reflecting layer on the transparent ball of the fixing layer by vapor deposition, making the surface of the fixing layer along the surface of the temporary fixing layer, and transferring the transparent ball onto the fixing layer from the pressed rear fixing layer glass temporary fixing layer, and providing a light transmission part without the transparent ball on the fixing layer.

In the patent document 3, since the reflective layer is not formed on the portion other than the transparent ball, even if the printed layer or the hologram for indicating the vehicle information such as the character information and the barcode is provided on the surface layer side, there is a disadvantage that visibility is poor because of the light-transmitting portion. Further, when the retroreflective sheet is used as a retroreflective sheet, since a direct reflective layer is formed on the back surface of the transparent sphere, the sheet is used for an exposed lens type or a capsule lens type, and an air layer needs to be provided on the upper portion of the transparent sphere, which is problematic when the sheet is used as a security label. In the manufacturing method, after the transparent ball is once embedded in the temporary fixing layer, the transparent ball is transferred to the fixing layer by pressing, which complicates the process, and there is no description about a method of making a portion where the transparent ball is not provided completely opaque. Further, when an image is formed using a sublimable coloring agent, the air layer is expanded into a bubble form by heating at the time of image formation, and the appearance of the retroreflective sheet is impaired, or a film forming the air layer is broken, which is not preferable.

Patent document 1: japanese laid-open patent publication No. 2002-366036

Patent document 2: japanese laid-open patent publication No. 2000-206884

Patent document 3: japanese laid-open patent publication No. 2002-14212

Disclosure of Invention

Accordingly, an object of the present invention is to provide a retroreflective security sheet which is difficult to forge, cannot be reused when peeled off, can be visually recognized without being affected by an object to be pasted such as colored glass, and can be clearly recognized even at night, and a method for manufacturing the retroreflective security sheet.

The retroreflective sheet for security of the present invention comprises, in order: a surface layer, an adhesive layer, high refractive index glass beads, a printing resin layer, a focus layer, a metal layer, and a pressure sensitive adhesive layer,

wherein the printing resin layer forms a mark,

the adhesive layer is provided with high-refractive-index glass beads,

the arrangement position of the high refractive index glass beads and the position of the printing resin layer do not overlap when viewed from the surface layer direction to the thickness direction of the retroreflective sheet for safety,

the printing resin layer is formed of a composition containing a room temperature curable resin as a main component.

The retroreflective sheeting with an image for security of the present invention comprises in order:

a surface resin layer which has a weak affinity with a sublimable coloring agent and allows the coloring agent to pass therethrough, a printing layer which has an affinity with the sublimable coloring agent and in which an image is formed in a thickness direction of the layer by the sublimable coloring agent, and a dye migration preventing resin layer which prevents migration of the sublimable coloring agent, an adhesive layer, high refractive index glass beads, a printing resin layer, a focus layer, a metal layer, and a pressure-sensitive adhesive layer, wherein,

the printed resin layer forms a mark, the binder layer has high-refractive-index glass beads disposed therein, and when viewed from the surface layer direction in the thickness direction of the image-bearing retroreflective sheet for security, the positions of the high-refractive-index glass beads and the positions of the printed resin layer do not overlap, and the printed resin layer is formed from a composition containing a room-temperature curable resin as a main component.

The retroreflective security sheet of the present invention has a special structure that is generally difficult to obtain in the market, in which the position of the printed resin layer and the arrangement position of the high-refractive-index glass beads do not overlap, and therefore, the effect of preventing forgery can be improved. Further, after the retroreflective sheet for security of the present invention is attached to an object to be attached, if it is peeled off, the metal layer is destroyed and cannot be reused. Further, since the retroreflective sheet for safety of the present invention contains the high refractive glass beads and the like, the mark formed on the printed resin layer is clearly recognized even at night.

Drawings

Fig. 1 is a cross-sectional view showing an example of a retroreflective security sheet of the present invention.

Fig. 2 is a cross-sectional view showing another example of the retroreflective security sheet of the present invention.

Fig. 3 is a cross-sectional view showing another example of the retroreflective security sheet of the present invention.

Fig. 4 is a cross-sectional view showing another example of the retroreflective security sheet of the present invention.

Fig. 5 is a cross-sectional view showing another example of a retroreflective security sheet blank of the present invention.

Fig. 6 is a cross-sectional view showing an example of a process for manufacturing the retroreflective security sheet of the present invention.

Fig. 7 is a cross-sectional view showing another example of a process for manufacturing the retroreflective security sheet of the present invention.

Fig. 8 is a cross-sectional view showing another example of a process for manufacturing the retroreflective security sheet of the present invention.

Fig. 9 is a cross-sectional view showing another example of a process for manufacturing the retroreflective security sheet of the present invention.

Fig. 10 is a cross-sectional view showing another example of a process for manufacturing the retroreflective security sheet of the present invention.

Fig. 11 is a cross-sectional view showing an example of a retroreflective sheet with an image for security according to the present invention.

Fig. 12 is a cross-sectional view showing an example of a process for manufacturing a retroreflective sheet with an image for security according to the present invention.

Fig. 13 is a cross-sectional view of another example of a security retroreflective sheet of the present invention having an image formed thereon.

Fig. 14 is a cross-sectional view showing an example of a retroreflective security sheet with a release material according to the present invention.

Fig. 15 is a cross-sectional view showing another example of a retroreflective security sheet with a release material according to the present invention.

Fig. 16 is a cross-sectional view showing an example of a retroreflective sheet for security use with a release material according to the present invention.

FIG. 17 is a cross-sectional view showing another example of a security image-bearing retroreflective sheet with release material of the present invention.

Detailed Description

In the retroreflective sheet for security (image-bearing) of the present invention, the arrangement position of the high refractive index glass beads and the position of the printed resin layer do not overlap when viewed from the surface layer direction in the thickness direction of the retroreflective sheet for security (image-bearing). Therefore, when the retroreflective sheet for security (with an image) is viewed from the front surface layer side, the metal layer can be seen without the printed resin layer being partially covered by the glass beads. As a result, the mark formed on the printed resin layer can be recognized as a metallic tone in the retroreflective sheet for security (with image) of the present invention.

In the retroreflective sheet for security of the present invention, the adhesive layer is preferably formed of a composition containing a thermosetting resin. More preferably, the thermosetting resin composition is a composition containing a thermosetting resin which suppresses curing at room temperature, and still more preferably a composition containing a thermosetting resin which does not undergo curing at room temperature. The curing agent used in this case is preferably an amino resin, a blocked polyisocyanate resin, or the like. This is because, when the printing resin layer is formed from these compositions, curing of the pressure-sensitive adhesive layer is suppressed when the printing resin layer is cured at normal temperature, and then the heat-bonding performance of the pressure-sensitive adhesive layer is sufficiently maintained. Further, after the glass beads are provided, the pressure-sensitive adhesive layer can be cured by heating, and as a result, the glass beads are sufficiently fixed in the pressure-sensitive adhesive layer, and crosslinking is formed between the focal layer and the pressure-sensitive adhesive layer, and as a result, the interlayer adhesiveness between the focal layer and the pressure-sensitive adhesive layer can be improved.

The retroreflective sheet for safety of the present invention preferably further comprises a self-destructing layer between the focal layer and the metal layer. The self-destructing layer is preferably formed of a resin composition having low adhesion to the metal layer. This is because, when the retroreflective security sheet is attached to an object to be attached and then peeled off, the metal layer of the retroreflective security sheet is broken and cannot be reused, which is preferable. In addition, the retroreflective sheet for security of the present invention preferably further comprises a self-destructing layer, and the pressure-sensitive adhesive layer is provided between the metal layer and the self-destructing layer. The self-destructing layer used in this case is preferably a film containing a hologram image or a diffraction grating, or a film obtained by subjecting a brittle film or a carrier film to a regular or irregular peeling treatment. The film is preferably used because when it is stuck to the outside of a window glass of a vehicle or the like, a hologram, a diffraction grating, or the like can be seen when it is viewed from the inside of the window glass, and whether or not forgery has been made can be easily determined. Further, when the retroreflective security sheet is attached to an object to be pasted and then peeled off, the film containing the hologram image or diffraction grating of the retroreflective security sheet is broken and cannot be reused, and such a film is preferable.

In the retroreflective sheet for security of the present invention, the surface layer and the adhesive layer are preferably formed of the same resin composition. When the surface layer and the adhesive layer are made of the same composition, the surface layer and the adhesive layer can be produced as a single layer at a time, which is preferable because the processing cost can be reduced.

In the retroreflective security sheet of the present invention, which is a retroreflective security sheet that can be colored by heating to allow a sublimable coloring agent to penetrate into the image-forming resin layer, the surface layer preferably comprises, in order from the surface: a surface resin layer having a low affinity with the sublimable coloring agent and allowing the coloring agent to pass therethrough, an image forming resin layer having an affinity with the coloring agent, and a dye migration preventing resin layer preventing migration of the coloring agent. When the surface resin layer, the image forming resin layer and the dye migration prevention resin layer are contained, the coloring agent can be introduced into the image forming resin layer from one side of the surface resin layer, and the coloring agent can be allowed to penetrate into the image forming resin layer by heating to form an image. Further, since the image is formed in this manner, the image can be formed in the thickness direction of the aforementioned image forming resin layer. Therefore, the image has a three-dimensional appearance, and the printed layer cannot be scratched to thereby make falsification prevention impossible, and the forgery prevention effect can be dramatically improved.

In the retroreflective sheet for safety of the present invention, the dye migration preventing resin layer is preferably a resin layer containing a vinyl resin having a glass transition temperature (Tg) of 70 ℃ or higher and an SP value of 9.0 or higher as a main component. Since such a dye migration prevention resin layer is contained, it is possible to prevent the sublimable coloring agent from migrating to the pressure-sensitive adhesive layer after a lapse of time, generating image contour blurring or the like, and making the image unclear. Therefore, the image formed on the image-forming resin layer of the retroreflective sheet for security of the present invention can be kept stable for a long period of time. Furthermore, since flexibility can be imparted by providing such a dye migration preventing resin layer and adding a plasticizer or the like to the binder layer of the retroreflective security sheet, flexibility and stretchability required for following a 3-dimensional curved surface can be obtained when the retroreflective security sheet is adhered to an adhesion target surface of the curved surface.

In the retroreflective sheet for security of the present invention, the thickness of the dye migration preventing resin layer is preferably 1 μm to 100 μm. This is because when the film thickness is 1 μm or more, a sufficient dye migration preventing effect can be exhibited; when the film thickness is 100 μm or less, rigidity can be avoided and adhesion to a substrate becomes easy. The film thickness is preferably 2 to 80 μm, more preferably 3 to 60 μm.

In the retroreflective sheet for security of the present invention, the dye migration preventing resin layer is preferably a biaxially oriented film stretched by 10% or more in the winding direction and the width direction, respectively. As long as such a biaxially oriented film is used, it is possible to prevent: after a lapse of time, the sublimable coloring agent migrates to the pressure-sensitive adhesive layer, and a case where an image contour blur or the like occurs to make the image unclear occurs. Therefore, the image formed on the image-forming resin layer of the retroreflective sheet for security of the present invention is stable for a long time.

In the retroreflective sheet for safety of the present invention, the biaxially oriented film has a shrinkage ratio in the film winding direction of 1.0% or less when heated at 150 ℃ for 30 minutes. By using such a biaxially oriented film with a low shrinkage ratio, the occurrence of wrinkles and streaks can be suppressed.

In the retroreflective sheet for security of the present invention, the image-forming resin layer is preferably a resin layer containing 0 to 20 wt% of a low-molecular-weight compound having a molecular weight of 1300 or less. By reducing the content of the low-molecular weight compound, the occurrence of migration of the dye from the aforementioned image-forming resin layer can be prevented.

The retroreflective sheet blank for security of the present invention is a blank for a retroreflective sheet for security of the present invention, characterized by comprising a surface layer, an adhesive layer, high-refractive-index glass beads, a printing resin layer, a focus layer and a metal layer in this order; the printed resin layer forms a mark, the binder layer has high-refractive-index glass beads disposed therein, and when viewed from the surface layer direction in the thickness direction of the retroreflective sheet for safety, the positions of the high-refractive-index glass beads and the positions of the printed resin layer do not overlap, and the printed resin layer is formed from a composition containing a room-temperature curable resin as a main component.

The method of making a security retroreflective sheeting of the present invention comprises the steps of: laminating an adhesive layer on a surface layer, printing on the adhesive layer to form a printed resin layer, curing the printed resin layer at normal temperature, heating the adhesive layer until the adhesive layer reaches a temperature at which the adhesive layer exhibits adhesiveness, embedding glass beads in portions of the adhesive layer where the printed resin layer is not formed, laminating a focus layer on the adhesive layer, the printed resin layer, and the high-refractive-index glass beads, forming a metal layer on the focus layer, and forming a pressure-sensitive adhesive layer on the metal layer.

In this production method, even when the pressure-sensitive adhesive layer is heated to a temperature at which the pressure-sensitive adhesive layer exhibits adhesiveness, since the printing resin layer does not exhibit adhesiveness, even if the high-refractive-index glass beads are embedded in the pressure-sensitive adhesive layer, they are not embedded in the portion where the printing resin layer is formed. Therefore, when the retroreflective sheet for safety is viewed from the front surface layer side, the metal layer can be seen without the printed resin layer being partially covered by the glass beads. As a result, the retroreflective sheeting for security of the present invention can be seen with a metallic color tone of the mark formed by the printed resin layer.

Preferably, the surface layer comprises, in order from the surface: a surface resin layer which has a weak affinity with the sublimable coloring agent and allows the coloring agent to pass therethrough, an image forming resin layer having an affinity with the coloring agent, and a dye migration preventing resin layer which prevents migration of the coloring agent; and an adhesive layer is laminated on the dye migration prevention resin layer. When the surface resin layer, the image-forming resin layer, and the dye migration prevention resin layer are contained, the coloring agent may be introduced from the surface resin layer into the image-forming resin layer, and the coloring agent may be allowed to penetrate into the image-forming resin layer by heating to form an image. Further, since the image is formed in this manner, an image can be formed in the thickness direction of the layer in the aforementioned image forming resin layer. Therefore, the image has a three-dimensional appearance, and the printed layer cannot be scratched to thereby prevent falsification, and the forgery prevention effect can be dramatically improved.

As described above, the retroreflective sheet with an image for security of the present invention is characterized by comprising, in order, a surface resin layer which has a weak affinity for a sublimable coloring agent and allows the coloring agent to pass therethrough, a printing layer which has an affinity for the sublimable coloring agent and on which an image is formed in the thickness direction of the layer by the sublimable coloring agent, a dye migration preventing resin layer which prevents migration of the coloring agent, an adhesive layer, high refractive index glass beads, a printing resin layer, a focus layer, a metal layer, and a pressure-sensitive adhesive layer; the printed resin layer forms a mark, the binder layer has high-refractive-index glass beads disposed therein, and when viewed from the surface layer direction in the thickness direction of the image-bearing retroreflective sheet for security, the positions of the high-refractive-index glass beads and the positions of the printed resin layer do not overlap, and the printed resin layer is formed from a composition containing a room-temperature curable resin as a main component. Since such a retroreflective sheet with an image for security contains a printed layer in which a sublimable coloring agent having excellent transparency is sublimated and an image is formed in the thickness direction of the layer, the image has a three-dimensional appearance, and thus the image cannot be falsified by scraping the printed layer, and the forgery prevention effect can be dramatically improved. Preferably, a self-destructing layer is further included between the focal layer and the metal layer. Further, it is preferable that the pressure-sensitive adhesive further contains a self-destructing layer, and the pressure-sensitive adhesive layer is provided between the metal layer and the self-destructing layer. The surface resin layer, the dye migration preventing resin layer, the pressure-sensitive adhesive layer, the high-refractive-index glass beads, the printing resin layer, the focus layer, the metal layer, the adhesive material layer, and the self-destructing layer are preferably the same as those contained in the retroreflective security sheet. The resin of the printing layer is preferably the same as the image-forming resin layer of the retroreflective security sheet.

A method for producing an image-bearing retroreflective sheet for security according to the present invention (hereinafter referred to as the 1 st method for producing an image-bearing retroreflective sheet for security according to the present invention) comprising the steps of: printing is performed on a transfer paper using an ink containing a sublimable coloring agent, the image-forming surface of the transfer paper is brought into contact with the surface resin layer side of the retroreflective sheet for security of the present invention, and then a heating treatment is performed to sublimate the sublimable coloring agent to penetrate the surface resin layer to form an image in the image-forming resin layer, thereby obtaining a printing layer, and the transfer paper is removed. The retroreflective sheet for security use of the present invention used in the method 1 for producing the retroreflective sheet for security use with an image according to the present invention comprises the surface resin layer, the image-forming resin layer, the dye migration preventing resin layer, the adhesive layer, the high-refractive-index glass beads, the printing resin layer, the focus layer, the metal layer, and the pressure-sensitive adhesive layer in this order. In this manufacturing method, since the sublimable coloring agent is sublimated from the surface resin layer side to be colored, and an image is formed inside the image forming resin layer, not only character information but also a clear image such as a photographic image of a vehicle can be obtained. Further, by the foregoing dye migration prevention resin layer, it is possible to prevent the sublimation coloring agent from migrating to the pressure-sensitive adhesive layer after a lapse of time, generating image contour blur or the like, and making the image unclear.

A method for producing an image-bearing retroreflective sheet for security according to the present invention (hereinafter referred to as the 2 nd process for producing an image-bearing retroreflective sheet for security according to the present invention) comprising the steps of, in order, the surface resin layer, the printing layer having an affinity for the sublimable coloring agent and having an image formed by the sublimable coloring agent in the thickness direction of the layer, the dye migration preventing resin layer, the adhesive layer, the high refractive glass beads, the printing resin layer, the focus layer, the metal layer, and the pressure-sensitive adhesive layer, wherein a releasable ink-receiving layer having the following properties is formed on the surface resin layer of the retroreflective sheet for security according to the present invention: the printing display can be carried out; a surface side which is in contact with the surface resin layer and which is absorptive for ink containing the coloring agent, and which is capable of forming an image in the image forming resin layer by sublimating the coloring agent through the surface resin layer by a heat treatment; and can be peeled off from the surface resin layer in a film state after the heat treatment; printing on the ink-containing layer using an ink containing a sublimable coloring agent; then, carrying out heating treatment to sublimate the sublimable coloring agent to penetrate through the surface resin layer, and forming an image in the image forming resin layer to obtain a printing layer; and peeling off the peelable ink-receiving layer. The retroreflective sheet for security use of the present invention used in the method 2 for producing the retroreflective sheet for security use with an image according to the present invention comprises the surface resin layer, the image-forming resin layer, the dye migration preventing resin layer, the adhesive layer, the high-refractive-index glass beads, the printing resin layer, the focal layer, the metal layer, and the pressure-sensitive adhesive layer in this order. This manufacturing method is preferable because the image printing step and the sublimation dyeing step on the ink-receiving layer can be automated when forming an image on the image-forming resin layer, and the retroreflective sheet for safety can be easily manufactured.

The retroreflective sheet for security and the method for manufacturing the same according to the present invention will be described in detail below based on examples.

(embodiment 1)

Fig. 1 is a cross-sectional view showing an example of a retroreflective security sheet of the present invention. The retroreflective security sheet 100 is formed by laminating a surface layer 1, an adhesive layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5, a metal layer 6, and a pressure-sensitive adhesive layer 7 in this order.

As the material of the surface layer 1 and the adhesive layer 2, specifically, for example, a fluoroolefin copolymer containing a reactive functional group, a polyester-based resin, an alkyd-based resin, a polyurethane-based resin, a vinyl-based resin, an acrylic polymer containing a reactive functional group may be used as a raw material resin component, and a curing agent and/or a curing catalyst such as an amino resin, an epoxy resin, a polyisocyanate, a blocked polyisocyanate may be mixed, and the resin thus obtained may be used as the surface layer; as the curing agent for the pressure-sensitive adhesive layer, a curing agent which is not curable at room temperature, such as an amino resin or a blocked polyisocyanate, can be used. The resin components listed as the materials of the surface layer 1 and the adhesive layer may be used alone or in combination of two or more. The resin used for the surface layer 1 and the pressure-sensitive adhesive layer 2 may be any of a solution type, a non-aqueous dispersion type, a water-soluble type, and an aqueous dispersion type, and a solution type is particularly preferable. The higher the molecular weight of the resin composition forming the pressure-sensitive adhesive layer 2, the lower the adhesiveness at room temperature, and therefore, the higher the pressure-sensitive adhesive strength. The dry film thickness of the pressure-sensitive adhesive layer 2 may be, for example, 10 to 90%, preferably 20 to 80%, and more preferably 30 to 70% of the particle diameter of the glass beads.

The surface layer 1 may be formed by coating a polyester film, which is an engineering film, on the surface layer and drying the polyester film, and then laminating an adhesive layer thereon. The aforementioned surface layer 1 may have a multilayer structure of 2 layers or more as necessary. Further, the surface layer 1 and the adhesive layer 2 are made of the same composition, so that the surface layer and the adhesive layer can be made of the same layer. In this case, the pressure-sensitive adhesive layer may be formed by directly applying the pressure-sensitive adhesive layer resin to the engineering film and drying the applied resin, and the pressure-sensitive adhesive layer may be formed to have a thickness similar to that of the surface layer. The engineering film may be peeled off as necessary during the production process of the retroreflective sheet for safety of the present invention or after the completion of the final process.

Further, when a polyester resin film is used as the surface layer 1, the engineering film used in the production of the surface layer 1 also serves as the surface layer 1, and therefore, it is preferable to use it as it is as the surface layer 1. The surface layer 1 is preferably a stretched film, and more preferably a biaxially stretched film.

Further, as the material of the pressure-sensitive adhesive layer 2, a composition containing a thermosetting resin is more preferable. The pressure-sensitive adhesive layer 2 formed from such a composition is preferably composed of a composition containing a thermosetting resin whose curing is suppressed at room temperature, more preferably a thermosetting resin which does not undergo curing at room temperature, so as to be in a thermoplastic state although containing a thermosetting component, as a system for maintaining heat adhesiveness. Thus, in one example of the method for producing the retroreflective security sheet of the present invention, the adhesive layer 2 can be made to exhibit adhesiveness by heating. More preferably, it is at 172gf/cm²(1.687N/cm²) The pressure-sensitive adhesive layer 2 and the inner surface of the engineering film used as a support film for producing the surface layer 1 and the pressure-sensitive adhesive layer 2 are free from blocking in a blocking test under a load of (1) at room temperature for 10 days.

The high refractive index glass beads 3 include, for example, glass beads having a refractive index of 2.00 to 2.40, preferably 2.10 to 2.30. This is because, if the refractive index is 2.0 or more, the film thickness necessary for the focal layer becomes too thick, and therefore, the resin is easily formed concentrically with the spherical diameter of the glass beads at the heating temperature at the time of forming the focal layer. Further, when the refractive index is 2.4 or less, the glass beads having such a refractive index can be prevented from crystallizing, and it is easy to industrially produce transparent glass beads with good accuracy. The particle size may be 5 to 300. mu.m, preferably 20 to 100. mu.m. This is because, if the particle diameter of the glass beads is 5 μm or more, the film thickness required for the focal layer is not extremely thin, and the film thickness can be controlled; when the particle diameter of the glass beads is 300 μm or less, since the film thickness required for the focal layer is not excessively thick, it becomes easy to form a resin concentrically with the spherical diameter of the glass beads at the heating temperature at the time of forming the focal layer.

The printing resin layer 4 is formed of a composition containing a room temperature curable resin as a main component. In one example of the method for producing the retroreflective security sheet of the present invention, since the solvent is evaporated after the printed resin layer 4 is formed, the printed resin layer 4 formed of the composition must be wound up to be cured and dried at room temperature. In this case, the printing resin layer 4 is preferably non-adhesive. When the printing resin layer 4 is wound up as described above and cured at normal temperature, the adhesive layer 2 can be inhibited from exhibiting adhesiveness when heated to exhibit adhesiveness. As the material of the printing resin layer 4, a composition that can be three-dimensionally cured at ordinary temperature by the following reaction: resins such as alkyd resins, polyester resins, epoxy resins, urea resins, silicone resins, acrylic silicone resins, polyurethane resins, vinyl resins, and acrylic resins, and curing agents and/or curing catalysts that react with reactive functional groups introduced into the resins at room temperature.

The focus layer 5 may be formed of a composition containing, for example, a polyurethane resin, a polyvinyl acetal resin, an acrylic resin, an alkyd resin, a polyester resin, or the like as a base polymer component. These compositions may be of a non-crosslinked type, or may be of a thermosetting type in which a curing agent such as an amino resin, an epoxy resin, a polyisocyanate or a blocked polyisocyanate is mixed.

The metal layer 6 may be made of metal such as aluminum, gold, silver, copper, nickel, chromium, magnesium, or zinc, and among them, aluminum, chromium, or nickel is preferable in view of workability, easiness of forming the metal layer, durability of light reflection efficiency, and the like. Further, the metal layer 6 may be formed of an alloy of 2 or more metals. The thickness of the metal layer 6 varies depending on the metal used, and may be, for example, 5 to 200nm, preferably 10 to 100 nm. When the thickness of the metal layer 6 is 5nm or more, the concealing property of the metal layer is sufficient, and therefore, the object of the reflective layer can be sufficiently achieved. Conversely, when the thickness of the metal layer 6 is 200nm or less, cracks are less likely to occur in the metal layer, and the cost is low, which is preferable.

The aforementioned pressure-sensitive adhesive layer 7 can be manufactured using a general pressure-sensitive adhesive. The thickness is also not particularly limited.

As the aforementioned pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive formed of an acrylate copolymer, a silicone-based pressure-sensitive adhesive formed of a silicone rubber and a silicone resin, and a rubber-based pressure-sensitive adhesive formed of a natural rubber and a synthetic rubber can be used. The rubber-based pressure-sensitive adhesive is mainly composed of natural rubber, synthetic rubber, and reclaimed rubber, and 3 components of a tackifier and an antiaging agent, and various materials such as a softener, a crosslinking agent, and a filler can be selected as necessary. As the acrylic pressure-sensitive adhesive, solvent-based, emulsion-based, water-soluble aqueous adhesives, hot-melt-based, and liquid-curing solventless adhesives can be used, and particularly, solvent-based adhesives are preferable because they are excellent in weather resistance and heat aging resistance and can maintain high permanent joining and releasing properties reliably over a long period of time. Further, in order to improve heat resistance, solvent resistance and plasticizer migration resistance, it is more preferable to mix a monomer having a functional group into the base polymer and then use a crosslinking agent that reacts with the functional group. Examples of the acrylic monomer having a functional group include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, glycidyl acrylate, glycidyl methacrylate, N-methylolacrylamide, N-methylolmethacrylamide, dimethylaminoethyl methacrylate, and t-butylaminoethyl methacrylate, and examples of the crosslinking agent include melamine resin, urea resin, polyisocyanate, epoxy resin, metal chelate, a polymer containing-COOH, acid anhydride, polyamine, and the like. In addition, in order to suppress the generation of harmful substances such as formaldehyde and irritating components during the heating, curing agents such as epoxy resins, metal chelates, and aliphatic polyisocyanates are more preferably used. Further, a tackifier may be used as necessary to compensate for the adhesiveness to polyolefin and the adhesive at low temperature. In addition, when heat resistance and cold resistance are particularly required, a silicone pressure-sensitive adhesive is preferably used.

Examples of the mark included in the security retroreflective sheet include a car number, a validity period, a national flag (official seal such as a prefecture or a state seal), a photograph of a vehicle, vehicle information such as a bar code corresponding to a part or all of the vehicle information, individual information such as a name of an owner, and a symbol mark printed in a shallow manner on the entire security retroreflective sheet (see fig. 13). By combining these images and printing, the forgery prevention performance of the retroreflective sheet for security of the present invention can be further improved.

Further, when higher security performance is required, an IC element capable of inputting a larger amount of information may be used. In this case, the IC device may be laminated on the surface of the surface resin layer 11 described later via an adhesive layer or a pressure-sensitive adhesive layer. Further, it is preferable to attach a fragile film to the IC element via an adhesive layer or a pressure-sensitive adhesive layer because the IC element cannot be replaced by attachment and the anti-counterfeit performance can be further improved. Further, it is preferable that a space for attaching an IC element is provided in the surface resin layer 11 so that no image is formed on an image forming resin layer 12 described later in a corresponding portion below the space. This is because, when an image is formed on the image forming resin layer 12 which is a lower layer of the space to which the IC element is attached, the sublimable coloring agent migrates to the pressure-sensitive adhesive layer of the IC element through the surface resin layer 11 after a lapse of time, and the image becomes unclear, for example, the image is blurred.

Examples of the IC device include a non-contact type and Proximity (Proximity) type IC device, which preferably includes a CPU: central processing unit, RAM: high-speed memory for general data, ROM: read only memory, EEPROM for storing programs: read-only memory for storing data, interface: implementing communication control between the IC card and the outside, and the coprocessor: a dedicated processor for high-speed processing of RSA data also has an antenna coil connecting these elements.

(embodiment mode 2)

Fig. 2 is a cross-sectional view of another example of a security retroreflective sheeting of the present invention. The retroreflective security sheet 200 is formed by laminating a surface layer 1, an adhesive layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5, a self-destructing layer 8, a metal layer 6 and a pressure-sensitive adhesive layer 7 in this order.

The aforementioned surface layer 1, adhesive layer 2, high-refractive-index glass beads 3, printing resin layer 4, focus layer 5, metal layer 6, and pressure-sensitive adhesive layer 7 are the same as those described in embodiment 1.

The self-destructing layer 8 is preferably formed using a resin composition having low adhesion to the metal layer 6. Examples of such a resin composition include a composition containing a silicone resin, a fluorine resin, an alkyd resin, an acrylic resin, a cellulose resin, or the like as a base polymer component. The self-destructing layer 8 may have a regular or irregular pattern.

(embodiment mode 3)

Fig. 3 is a cross-sectional view of another example of a security retroreflective sheeting of the present invention. The retroreflective security sheet 300 is formed by laminating a surface layer 1, an adhesive layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5, a metal layer 6, a pressure-sensitive adhesive layer 7, and a self-destructing layer 18 in this order.

As described above, the self-destructing layer 18 is preferably a film containing a hologram having an arbitrary predetermined pattern or a diffraction grating, or a self-destructing film obtained by subjecting a brittle film or a carrier film to a regular or irregular peeling treatment.

In this case, in order to be stuck to a window glass such as a window glass, a pressure-sensitive adhesive layer may be formed on a self-destructing layer in the same manner as in embodiment 1, for example, by sticking a pressure-sensitive adhesive layer formed on a separate release film to the self-destructing layer.

The hologram image may be any of a planar hologram image and a stereoscopic hologram image, and in the case of a planar hologram image, a relief hologram is preferable from the viewpoint of mass productivity, durability, and cost, and in the case of a stereoscopic hologram image, a Lippmann (Lippmann) hologram is preferable from the viewpoint of image reproducibility and mass productivity. Further, laser holograms such as Fresnel (Fresnel) holograms, Fraunhofer (Fraunhofer) holograms, lensless fourier transform holograms, image holograms, and white light reconstruction holograms such as rainbow holograms, as well as color holograms, computer holograms, holographic displays, multiplexed holograms, holographic stereograms, and the like, to which these principles are applied, may be used.

As the diffraction grating, a diffraction grating mechanically formed by a hologram diffraction grating, an electron beam plotter, or the like can be used.

Examples of the resin for forming the brittle film include thermoplastic resins such as polyvinyl alcohol having a low degree of polymerization, acrylic resins, polystyrene, polyvinyl chloride, nitrocellulose resins, acetyl cellulose resins, cellulose acetate butyrate resins, and vinyl chloride vinyl acetate copolymers, and a transparent ultraviolet-curable polymer resin obtained by compounding these resins, or a transparent electron beam-curable polymer resin obtained by compounding these resins, and unsaturated polyester, polyurethane, epoxy transparent thermosetting polymer resins of low degree of polymerization, and ultraviolet-curable monomer resins obtained by compounding these resins, or an electron-ray-curable monomer resin obtained by compounding these resins, and a drying oil-based transparent varnish such as a polyester-based or polyurethane-based thermosetting monomer resin, a silicone resin, paraffin wax, or linseed oil. Examples of the carrier film include polyester films, polycarbonate films, acrylic resin films, and cellulose resin films.

Examples of the release treatment agent include silicone resins, fluorine resins, acrylic resins, alkyd resins, chlorinated rubber resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, chlorinated polypropylene resins, and resins containing silicone oil, fatty acid amide, zinc stearate, and the like. In addition, inorganic substances may be used.

(embodiment mode 4)

Fig. 4 is a cross-sectional view of another example of a security retroreflective sheeting of the present invention. The retroreflective security sheet 400 is formed by laminating a surface layer 1, an adhesive layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5, a metal layer 6, and a pressure-sensitive adhesive layer 7 in this order. The surface layer 1 is formed by laminating a surface resin layer 11, an image forming resin layer 12, and a dye migration preventing resin layer 13 in this order.

The foregoing adhesive layer 2, high refractive index glass beads 3, printing resin layer 4, focus layer 5, metal layer 6 and pressure-sensitive adhesive layer 7 are the same as those described in embodiment 1.

As described above, the surface resin layer 11 preferably has a low affinity with the sublimable coloring agent and allows the coloring agent to pass therethrough. Examples of the material of the surface resin layer 11 include olefin resins such as polyethylene and polypropylene, vinyl alcohol resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer resins, fluorine resins, silicone resins, and mixtures thereof. Among them, as a material of the surface resin layer 11, a synthetic resin mainly composed of a fluorine-based resin and a silicon-modified acrylic resin is preferable. This is because they have high ultraviolet ray resistance and high non-affinity with a coloring agent.

The surface resin layer 11 may optionally contain an additive. The dry film thickness of the surface resin layer 11 may be, for example, about 1 μm to about 80 μm, preferably about 2 μm to about 60 μm, and more preferably about 3 μm to about 40 μm.

Examples of synthetic resins containing a fluorine-based resin as a main component include a fluoro-olefin copolymer such as a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, a tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, a tetrafluoroethylene-ethylene copolymer, or a chlorotrifluoroethylene-ethylene copolymer, and a fluorine-based resin such as polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinylidene fluoride, or polyvinyl fluoride.

When the surface resin layer is prepared using a synthetic resin containing a fluorine-based resin as a main component, a method of forming a fluorine resin formed of a fluoro olefin-based copolymer into a film by a processing method such as a solution casting method (casting method) is preferable. Further, a method of forming a film by reacting a fluoroolefin copolymer having a reactive functional group and being soluble in a solvent with a curing agent and/or a curing catalyst which react with the reactive functional group is more preferable.

Specific representative examples of the synthetic resin containing a silicon-modified acrylic resin as a main component include the following.

(1) A cured film is formed by adding a hydrolysis catalyst to a vinyl copolymer obtained by copolymerizing a vinyl monomer having a hydrolyzable silyl group.

(2) A cured film is formed by adding a compound having both an epoxy group and a hydrolyzable silyl group in one molecule to a vinyl copolymer obtained by copolymerizing a vinyl monomer having an amine group and/or a carboxyl group.

(3) A cured film formed by graft polymerizing a silicone resin and adding a polyisocyanate compound to a vinyl copolymer having hydroxyl groups.

(4) A cured film formed by graft polymerizing a silicone resin and adding a hydrolyzable catalyst to a hydrolyzable silyl group-containing vinyl copolymer.

Since the surface resin layer 11 is located on the outermost layer of the retroreflective sheet for security of the present invention, that is, on the outer side of the printed layer, the coloring agent forming the image on the printed layer can be protected from ultraviolet rays, wipers, and water, and the durability can be improved.

Examples of the additives contained in the surface resin layer 11, the image-forming resin layer 12, and the dye migration preventing resin layer 13 include ultraviolet absorbers, light stabilizers, and antioxidants. Which may be used individually or in combination. This is because, by containing these additives, the durability of the surface resin layer 11, the image forming resin layer 12, and the dye migration preventing resin layer 13 can be further improved.

As the ultraviolet absorber, known ultraviolet absorbers can be used, and for example, benzophenone-based, benzotriazole-based, cyanoacrylate-based, salicylate-based, oxalic acid anilide-based, and the like can be used. As the light stabilizer, a known light stabilizer, for example, a hindered amine compound, and the like can be used. Examples of the antioxidant include hindered phenol compounds, amine antioxidants, and sulfur antioxidants.

The additives contained in the surface resin layer 11, the image-forming resin layer 12, and the dye migration preventing resin layer 13 preferably have a large molecular weight. This is because the use of an additive having a relatively high molecular weight, such as an ultraviolet absorber, a light stabilizer, or an antioxidant, can suppress the occurrence of a phenomenon in which the additive volatilizes when heat treatment is performed on the surface resin layer side due to phase separation and bleeding from the surface resin layer.

As described above, the image forming resin layer 12 is preferably a layer having affinity with the sublimable coloring agent and capable of forming an image in the thickness direction of the layer by the sublimable coloring agent.

As a material of the image forming resin layer 12, a synthetic resin having affinity with the coloring agent is preferably used. Since the sublimation dye diffused by sublimation can be efficiently collected and the color can be developed at a high concentration. As a material of the image forming resin layer 12, a heat-resistant resin is more preferable. That is, there is no significant softening and sticking (sticky and sticky adhesiveness) at the heating temperature of about 150 to about 200 ℃ in sublimation dyeing. As a material of the image forming resin layer 12, a resin cured by radiation is particularly preferably used. Practical forms of radiation include electron rays, ultraviolet rays, nuclear radiation, microwave rays, and heat, and the aforementioned resins cured by radiation are well known in the art.

The image forming resin layer 12 contains 0 to 20 wt% of a low molecular weight compound having a molecular weight of 1300 or less, preferably 2000 or less, more preferably 3000 or less. This is because the low-molecular-weight compound gradually diffuses the sublimable coloring agent which is temporarily fixed, and as a result, a problem such as an unclear image is caused in the image-forming resin layer 12. The content of the low-molecular-weight compound in the image-forming resin layer 12 is 0 to 20 wt%, preferably 0 to 15 wt%, and more preferably 0 to 10 wt%.

The image-forming resin layer 12 may contain additives such as a plasticizer, and the content thereof is preferably low. This is because the additive causes the sublimable coloring agent which is temporarily fixed to gradually diffuse, and as a result, there is a possibility that the image of the image forming resin layer 12 may have a problem such as an unclear outline.

From the viewpoint of protecting the sublimable coloring agent from ultraviolet rays, the ultraviolet absorber is preferably uniformly dispersed in the image forming resin layer 12 so as to block 70% or more, more preferably 80% or more, and still more preferably 90% or more of ultraviolet rays. As a material of the image forming resin layer 12 that satisfies such required characteristics, a synthetic resin such as an acrylic resin, an alkyd resin, a polyester resin, a polyurethane resin, or an epoxy resin can be used.

The dry film thickness of the image forming resin layer 12 may be, for example, about 3 μm to about 100 μm, preferably about 5 μm to about 80 μm, and more preferably about 10 μm to about 60 μm.

As described above, the dye migration prevention resin layer 13 is preferably a resin layer containing a vinyl resin as a main component, the vinyl resin having a glass transition temperature (Tg) of 70 ℃ or higher and an SP value (Solubility Parameter) of 9.0 or higher. This prevents migration of the aforementioned coloring agent. The dye migration prevention resin layer 13 is particularly preferably formed of a resin containing an acrylic resin as a main component.

The Tg value is preferably 80 ℃ or higher, more preferably 90 ℃ or higher. When the Tg value is 70 ℃ or higher, migration of the sublimable coloring agent can be sufficiently prevented even at a high temperature outside the midsummer.

The SP value is preferably 9.25 or more, more preferably 9.50 or more. The SP value as used herein refers to a parameter indicating the polarity of the resin, and resins having a high SP value exhibit high polarity.

The SP value can be measured by the method described below, and when the acrylic resin is an acrylic copolymer, the SP value can be predicted by measuring in advance the SP value of the homopolymer of the acrylic monomer used. That is, the sum of products obtained by multiplying the weight ratios of the respective acrylic monomers constituting the copolymer and the SP value of the homopolymer is estimated as the SP value of the acrylic copolymer.

Examples of the actual measurement of the SP value of the acrylic monomer homopolymer include a homopolymer of methyl methacrylate of 10.6, a homopolymer of n-butyl methacrylate of 8.4, a homopolymer of ethyl methacrylate of 9.5, a homopolymer of β -hydroxyethyl methacrylate of 11.5, and a homopolymer of n-butyl acrylate of 8.6.

Using the above measured values, the SP value of an acrylic copolymer such as a copolymer consisting of methyl methacrylate/n-butyl acrylate/β -hydroxyethyl methacrylate (weight ratio) 50/40/10 can be estimated as: (10.6 × 0.5) + (8.6 × 0.4) + (11.5 × 0.1) ═ 9.89. The SP value of this copolymer was 9.89, which is close to the value of 9.92 actually obtained by the following method.

The method for measuring the SP value of the acrylic resin is as follows.

0.5g of the solid resin was weighed into a 100ml Meyer flask, and 10ml of Tetrahydrofuran (THF) was added to dissolve the resin. The liquid temperature of the dissolved solution was kept at 25 ℃ and hexane was added dropwise through a 50ml burette while stirring with a magnetic stirrer, to determine the amount (Vh) of hexane added dropwise when turbidity occurred in the solution (cloud point).

The hexane was then replaced with deionized water and the drop at the cloud point (Vd) was determined.

The SP value δ of the resin can be determined from the obtained Vh and Vd by the following formula shown in UH, CLARKE [ J.Polym.Sci.A-1, Vol.5, 1671-.

δ＝[(V_mh)^(1/2)δ_mh+(V_md)^(1/2)δ_md]/[(V_mh)^(1/2)+(V_md)^(1/2)]

Wherein the content of the first and second substances,

V_mh＝(V_h·V_t)/(φ_h·V_t+φ_t·V_h)

V_md＝(V_d·V_t)/(φ_d·V_t+φ_t·V_d)

δ_mh＝φ_h·δ_h+φ_t·δ_t

δ_md＝φ_d·δ_d+φ_t·δ_t

φ_h、φ_d、φ_t(ii) a Volume fractions of hexane, deionized water, THF at cloud point

(φ_h＝V_h/(V_h+10)、φ_d＝V_d/(V_d+10))

δ_h、δ_d、δ_t(ii) a SP value of hexane, deionized water, THF

V_h、V_d、V_t(ii) a Molecular volumes (ml/mol) of hexane, deionized water, THF

Examples of the vinyl monomer used in the production of the acrylic resin include aromatic monomers such as styrene, α -methylstyrene, p-tert-butylstyrene, and vinyltoluene;

(meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dibromopropyl (meth) acrylate, tribromophenyl (meth) acrylate, or alkoxyalkyl (meth) acrylate:

diesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid with 1-membered alcohols;

vinyl esters such as vinyl acetate, vinyl benzoate and "VEOVA" (trade name of vinyl ester manufactured by japan epoxy resin corporation);

a fluorine-containing polymerizable compound such as "VISKOTE 8F, 8FM, 17FM, 3F or 3 FM" (trade name of fluorine-containing acrylic monomer manufactured by Osaka organic chemistry Co., Ltd.), (per) fluoroalkyl-containing vinyl ester such as perfluorocyclohexyl (meth) acrylate, diperfluorocyclohexyl fumarate or N-isopropylperfluorooctanesulfonamidoethyl (meth) acrylate, vinyl ether, (meth) acrylate or unsaturated polycarboxylic acid ester;

amide bond-containing vinyl monomers such as (meth) acrylamide, dimethyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide, and alkoxylated N-methylolated (meth) acrylamides;

dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate;

carboxyl group-containing vinyl monomers such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid;

hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate;

examples of the other copolymerizable vinyl monomers include (meth) acrylonitrile, (glycidyl (meth) acrylate, (. beta. -methyl) glycidyl (meth) acrylate, allyl glycidyl ether, vinyl ethoxysilane,. alpha. -methacryloxypropyl trimethoxysilane, trimethylsiloxyethyl (meth) acrylate, and the like.

The acrylic resin used in the dye migration preventing resin layer 13 can be produced by a known polymerization (reaction) method such as a batch, semi-batch, or continuous solution polymerization method under normal pressure or under pressure using the vinyl monomers. In this case, a known radical polymerization catalyst such as azobisisobutyronitrile, benzoyl peroxide, t-butyl perbenzoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, or the like can be used alone or in combination depending on the polymerization conditions.

The solvent used in the solution polymerization may be suitably selected from aromatic hydrocarbons such as toluene and xylene, esters, ketones, alcohols and other solvents.

Some examples of the production of the acrylic resin having an SP value of 9.0 or more are shown below.

(reference example 1)

Into a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a condenser, 1000 parts of n-butyl acetate was charged and the temperature was raised to 110 ℃. A mixture of 650 parts of methyl methacrylate, 245 parts of n-butyl methacrylate, 100 parts of 2-hydroxyethyl methacrylate, 5 parts of methacrylic acid, 15 parts of tert-butylperoxy 2-ethylhexanoate is then added dropwise at 110 ℃ over a period of 4 hours. After completion of the dropwise addition, the reaction was continued for 6 hours while keeping the temperature at 110 ℃ to obtain an acrylic copolymer (a-1) having a nonvolatile content of about 50%. The SP value of the acrylic copolymer (a-1) obtained after drying was measured and found to be 10.16.

(reference examples 2 to 6)

Vinyl copolymers (a-2) to (a-6) were obtained in the same manner as in reference example 1, except that the ratio of the vinyl monomer was changed as shown in Table 1. The respective SP values measured after drying are shown in Table 1.

TABLE 1

Vinyl monomer (parts)	a-2	a-3	a-4	a-5	a-6
Vinyl monomer (parts)	a-2	a-3	a-4	a-5	a-6	Styrene (meth) acrylic acid ester	100	200	-	200	-
Methacrylic acid methyl ester	200	500	800	-	400	Styrene (meth) acrylic acid ester	100	200	-	200	-
Methacrylic acid methyl ester	200	500	800	-	400	Methacrylic acid ethyl ester	200	-	-	450	-
Acrylic acid ethyl ester	-	-	190	-	100	Methacrylic acid ethyl ester	200	-	-	450	-
Acrylic acid ethyl ester	-	-	190	-	100	Methacrylic acid n-butyl ester	100	200	-	-	300
(iv) tert-butyl methacrylate	-	-	-	200	-	Methacrylic acid n-butyl ester	100	200	-	-	300
(iv) tert-butyl methacrylate	-	-	-	200	-	Acrylic acid n-butyl ester	195	95	-	150	190
2-Hydroxyethyl methacrylate	200	-	-	-	-	Acrylic acid n-butyl ester	195	95	-	150	190
2-Hydroxyethyl methacrylate	200	-	-	-	-	Methacrylic acid	5	5	10	-	10
SP value	9.79	9.64	10.49	9.02	9.54	Methacrylic acid	5	5	10	-	10

When a resin mainly composed of such an acrylic resin is used in an uncured state in the dye migration prevention resin layer 13, or a crosslinked three-dimensional structure polymer formed by using an acrylic resin having a reactive functional group together with a curable substance that reacts with the reactive functional group is used, migration of a sublimable coloring agent can be prevented favorably.

The dye migration prevention resin layer 13 may optionally contain an additive.

The dry film thickness of the dye migration preventing resin layer 13 may be, for example, about 1 μm to about 100. mu.m, preferably about 2 μm to about 80 μm, and more preferably about 3 μm to about 60 μm.

The dye migration prevention resin layer 13 is preferably a biaxially oriented film stretched by 10% or more in the winding direction and the width direction, respectively. And the shrinkage rate of the dye migration prevention resin layer 13 in the film winding direction when heated at 150 ℃ for 30 minutes is 1.0% or less. The elongation of the biaxially oriented film is preferably 50% or more, more preferably 100% or more, and further preferably 200% or more. This is because, when the stretching ratio is 10% or more, migration of the sublimable coloring agent can be sufficiently prevented. The biaxially oriented film is preferably annealed at a glass transition temperature or higher by heating to fix the length or relax the film. The biaxially oriented film is shrunk by the heat of coloring by the heated sublimable coloring agent penetrating into the resin, and the occurrence of wrinkles and stripes can be suppressed. The shrinkage is preferably 0.8% or less, more preferably 0.6% or less. When the shrinkage ratio is 1.0% or less, the occurrence of wrinkles and streaks due to shrinkage of the biaxially oriented film upon heating can be suppressed. The biaxially oriented film is particularly preferably a polyester film.

The coloring agent for sublimation ink used in the present invention is preferably a dye that sublimates or evaporates at 70 to 260 ℃ under atmospheric pressure. Examples of the dye include dyes and basic dyes such as azo compounds, anthraquinones, quinophthalones, styryls, diphenylmethanes, triphenylmethanes, oxazines, triazines, xanthenes, methines, methyleneamides, acridines, and diazines. Among them, as the coloring agent, 1, 4-dimethylaminoanthraquinone, brominated or chlorinated 1, 5-dihydroxy-4, 8-diaminoanthraquinone, 1, 4-diamino-2, 3-dichloroanthraquinone, 1-amino-4-hydroxyanthraquinone, 1-amino-4-hydroxy-2- (. beta. -methoxyethoxy) anthraquinone, 1-amino-4-hydroxy-2-phenoxyanthraquinone, methyl ester, ethyl ester, propyl ester, butyl ester, 1, 4-diamino-2-methoxyanthraquinone, 1-amino-4-anilinoanthraquinone, 1-amino-2-cyano-4-anilino (or cyclohexylamino) anthraquinone, 1-amino-4-phenoxyanthraquinone, 1, 4-diaminoanthraquinone-2-carboxylic acid, and the like are preferable, 1-hydroxy-2- (p-acetamidophenylazo) -4-methylbenzene, 3-methyl-4- (nitrophenylazo) pyrazolone, 3-hydroxyquinophthalone, and the like.

As the basic dye, for example, malachite green, methyl violet, or the like can be used. Among these, as the basic dye, a dye modified with sodium acetate, sodium ethoxide, sodium methoxide, or the like is particularly preferably used.

(embodiment 5)

Fig. 5 is a cross-sectional view showing an example of a retroreflective security sheet blank of the present invention. The retroreflective security sheet blank 10 is formed by laminating a surface layer 1, a binder layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5, and a metal layer 6 in this order. The aforementioned surface layer 1, adhesive layer 2, high-refractive-index glass beads 3, printing resin layer 4, focus layer 5 and metal layer 6, which are the same as those described in embodiment 1. The retroreflective security sheet 100 can be obtained, for example, by forming the pressure-sensitive adhesive layer 7 on the metal layer 6 of the retroreflective security sheet blank 10. The pressure-sensitive adhesive layer 7 is the same as described in embodiment 1.

(embodiment mode 6)

An example of a method of manufacturing the retroreflective security sheet of the present invention will be described below. In FIGS. 6 to 10, 1 is a surface layer, 2 is an adhesive layer, 3 is a high refractive index glass bead, 4 is a printing resin layer, and 5 is a focus layer.

As described above, the method includes the steps of: an adhesive layer 2 is laminated on a surface layer 1 (see fig. 6), a printing resin layer 4 is printed and formed on the adhesive layer 2 (see fig. 7), the printing resin layer 4 is cured at normal temperature, the adhesive layer 2 is heated to a temperature at which the adhesive layer 2 exhibits adhesiveness, glass beads 3 are embedded in a portion of the adhesive layer 2 where the printing resin layer 4 is not formed (see fig. 8 and 9), a focus layer 5 is laminated on the adhesive layer 2 (see fig. 10), a metal layer is formed on the focus layer 5, and a pressure-sensitive adhesive layer is formed on the metal layer.

The step of laminating the pressure-sensitive adhesive layer 2 on the surface layer 1 may be performed by applying a solution containing the pressure-sensitive adhesive layer-forming resin so that the dry film thickness of the pressure-sensitive adhesive layer 2 is 10 to 90%, preferably 20 to 80%, and more preferably 30 to 70% of the particle diameter of the high-refractive-index glass strand 3 to be used, and drying the solution at room temperature or by heating to volatilize the solvent, and the volatilization of the solvent is preferably performed at a temperature at which the pressure-sensitive adhesive layer-forming resin is cured by heating or at a temperature lower than that. The probe tack (probtack) of the pressure-sensitive adhesive layer formed after the solvent is evaporated may be, for example, 0 to 40gf (0 to 392mN), preferably 0 to 30gf (0 to 294mN), and more preferably 0 to 20gf (0 to 196mN) at an ambient temperature of 23 + -2 ℃.

In general, since the printing process for printing and forming the printing resin layer 4 on the adhesive layer 2 is much faster than the speed of manufacturing the adhesive layer 2, when the transfer is made to the next printing process for printing the resin layer 4, the sheet of the adhesive layer 2 must be temporarily wound in a finished state. In this case, the probe tack of the pressure-sensitive adhesive layer 2 is preferably in the above range because the blocking (winding) phenomenon on the sheet of the pressure-sensitive adhesive layer 2 can be suppressed when the probe tack is 40gf (392mN) or less at an ambient temperature of 23. + -. 2 ℃. In addition, it is preferable that the printing resin layer 4 smoothly runs without contacting the guide roller with the pressure-sensitive adhesive layer 2 at the time of printing.

The probe tack is the tack strength measured under test conditions of a peel speed of 1 cm/sec, a measurement load of 9.8. + -. 0.1g (made of brass), a contact time of 1 second, a measurement environment of 23. + -. 2 ℃ and a relative humidity of 65. + -. 5% using a probe rod polished with a 5 mm. phi. stainless steel surface AA #400 and a mirror surface by a probe tack tester (manufactured by NICHIBAN K., based on ASTM D-2979).

The step of printing the printing resin layer 4 on the pressure-sensitive adhesive layer 2 may be performed by a known method such as gravure printing, screen printing, flexography, and relief printing.

The step of curing the printing resin layer 4 at room temperature may be performed, for example, at room temperature for 7 days, preferably 10 days, and more preferably 14 days.

The step of heating the pressure-sensitive adhesive layer 2 to a temperature at which the pressure-sensitive adhesive layer 2 exhibits adhesiveness varies depending on the kind of the resin forming the pressure-sensitive adhesive layer 2, and may be performed, for example, at 90 to 110 ℃, preferably 100 to 120 ℃, and more preferably 110 to 130 ℃. The heating time may be, for example, 0.5 to 1 minute, preferably 1 to 2 minutes, and more preferably 1.5 to 3 minutes.

The step of embedding the high refractive index glass beads 3 in the portion of the pressure-sensitive adhesive layer 2 where the printed resin layer 4 is not formed may be, for example, a step of heating the pressure-sensitive adhesive layer 2 to make it viscous, and then passing the laminate including the surface layer 1, the pressure-sensitive adhesive layer 2, and the printed resin layer 4 through a groove containing glass beads to disperse the high refractive index glass beads 3 in the surface of the pressure-sensitive adhesive layer 2 of the laminate. In this case, the high refractive index glass beads 3 are attached only to the adhesive region of the adhesive layer 2, and are not attached to the non-adhesive portion. Then, if further heated, the aforementioned glass beads 3 sink into the adhesive layer 2 and are fixed. The remaining foregoing glass beads 3 can then be removed by vacuum suction, water washing, or the like.

The step of laminating the focal layer 5 on the pressure-sensitive adhesive layer 2, the printing resin layer 4, and the high refractive index glass beads 3 is performed by applying a solution of the resin composition for the focal layer to an optimum dry film thickness as the focal layer 5, and then drying the resulting film at normal temperature or by heating. The drying conditions may be appropriately determined depending on the type of the resin for the focal layer, the type of the reactive functional group in the resin for the focal layer, the type of the curing agent, and the type of the solvent. The coating can be carried out by using a coating apparatus such as a knife coater, a comma coater, a roll coater, a reverse roll coater, a flow coater, or a spray coater.

The step of forming the metal layer on the focal layer 5 can be performed by a common vapor deposition method, sputtering method, transfer method, plasma method, or the like. From the viewpoint of workability, vapor deposition and sputtering are preferably employed.

The step of forming the pressure-sensitive adhesive layer on the aforementioned metal layer can be carried out by a conventionally known method.

(embodiment 7)

Next, an example of a method for producing a retroreflective security sheet according to the present invention will be described, wherein the surface layer comprises, in order from the surface: a surface resin layer having a weak affinity with the sublimable coloring agent and allowing the coloring agent to pass therethrough, an image forming resin layer having an affinity with the coloring agent, and a dye migration prevention resin layer preventing migration of the coloring agent, wherein the dye migration prevention resin layer is a resin layer mainly composed of a vinyl resin having a glass transition temperature (Tg) of 70 ℃ or higher and an SP value of 9.0 or higher. As described above, the manufacturing method includes the steps of: preparing a surface resin layer, forming an image forming resin layer on the surface resin layer, forming a dye migration prevention resin layer on the image forming resin layer, laminating an adhesive layer on the dye migration prevention resin layer, printing on the adhesive layer to form a printed resin layer, curing the printed resin layer at normal temperature, heating the adhesive layer until the adhesive layer reaches a temperature at which the adhesive layer exhibits adhesiveness, embedding high-refractive-index glass beads in a portion of the adhesive layer where the printed resin layer is not formed, laminating a focus layer on the adhesive layer, the printed resin layer, and the high-refractive-index glass beads, forming a metal layer on the focus layer, and forming a pressure-sensitive adhesive layer on the metal layer. The surface resin layer may be formed by a processing method such as a solution casting method (cast method) to form a resin as a material for forming the surface resin layer into a film shape. The step of forming the image forming resin layer on the surface resin layer may be performed, for example, by applying a solution of the material of the image forming resin layer on the surface resin layer and then drying the solution. The step of forming the dye migration prevention resin layer on the image forming resin layer may be performed, for example, by applying the vinyl-based resin of the dye migration prevention resin layer on the image forming resin layer and then drying the vinyl-based resin. The step of laminating the adhesive layer on the dye migration preventing resin layer is the same as the step of laminating the adhesive layer 2 on the surface layer 1 according to embodiment 6. A step of printing on the pressure-sensitive adhesive layer to form a printed resin layer, a step of curing the printed resin layer at normal temperature, a step of heating the pressure-sensitive adhesive layer to a temperature at which the pressure-sensitive adhesive layer exhibits adhesiveness, a step of embedding high-refractive-index glass beads in portions of the pressure-sensitive adhesive layer where the printed resin layer is not formed, a step of laminating a focus layer on the pressure-sensitive adhesive layer, the printed resin layer, and the high-refractive-index glass beads, a step of forming a metal layer on the focus layer, and a step of forming a pressure-sensitive adhesive layer on the metal layer are the same as those in embodiment 6.

(embodiment mode 8)

An example of the method for producing a retroreflective sheet for security of the present invention is described below, wherein the surface layer comprises, in order from the surface: the image forming apparatus comprises a surface resin layer having a weak affinity with the sublimable coloring agent and allowing the coloring agent to pass therethrough, an image forming resin layer having an affinity with the coloring agent, and a dye migration preventing resin layer preventing migration of the coloring agent, wherein the dye migration preventing resin layer is a biaxially stretched film stretched by 10% or more in a winding direction and a width direction, respectively. As described above, the manufacturing method includes the steps of: preparing the biaxially oriented film as a dye migration prevention resin layer, laminating an adhesive layer on the dye migration prevention resin layer, printing on the adhesive layer to form a printed resin layer, curing the printed resin layer at room temperature, heating the adhesive layer until the adhesive layer reaches a temperature at which the adhesive layer exhibits adhesiveness, embedding high-refractive-index glass beads in portions of the adhesive layer where the printed resin layer is not formed, laminating a focus layer on the adhesive layer, the printed resin layer, and the high-refractive-index glass beads, forming a metal layer on the focus layer, laminating adhesive layers formed on separate release films so as to face the metal layer, forming a pressure-sensitive adhesive layer on the metal layer, protecting the pressure-sensitive adhesive layer with the release films, and forming the image forming resin layer on the dye migration prevention resin layer, forming the surface resin layer on the image forming resin layer. The dye migration prevention resin layer can be prepared by, for example, biaxially stretching a polyester film. The step of laminating the adhesive layer on the dye migration preventing resin layer is the same as the step of laminating the adhesive layer 2 on the surface layer 1 according to embodiment 6. A step of printing on the pressure-sensitive adhesive layer to form a printed resin layer, a step of curing the printed resin layer at normal temperature, a step of heating the pressure-sensitive adhesive layer to a temperature at which the pressure-sensitive adhesive layer exhibits adhesiveness, a step of embedding high-refractive-index glass beads in portions of the pressure-sensitive adhesive layer where the printed resin layer is not formed, a step of laminating a focus layer on the pressure-sensitive adhesive layer, the printed resin layer, and the high-refractive-index glass beads, a step of forming a metal layer on the focus layer, and a step of forming a pressure-sensitive adhesive layer on the metal layer are the same as those in embodiment 6. The step of forming the image forming resin layer on the dye migration preventing resin layer may be performed as follows: for example, a solution of the material of the image forming resin layer is applied to the dye migration preventing resin layer, and then dried. The step of forming the surface resin layer on the image forming resin layer may be performed as follows: for example, a resin as a material for forming the surface resin layer is applied to the image forming resin layer and then dried.

(embodiment mode 9)

An example of a retroreflective sheeting with an image for security purposes of the present invention is described below. Fig. 11 is a cross-sectional view showing an example of a retroreflective sheet with an image for security according to the present invention. Retroreflective sheet 500 for security use having an image thereon is composed of surface layer 1, adhesive layer 2, high-refractive-index glass beads 3, printing resin layer 4, focus layer 5, metal layer 6 and pressure-sensitive adhesive layer 7 laminated in this order. The surface layer 1 is formed by sequentially laminating a surface resin layer 11, a printing layer 22 (containing a dye-dyed layer 50), and a dye migration preventing resin layer 13.

The aforementioned adhesive layer 2, high refractive index glass beads 3, printing resin layer 4, focus layer 5, metal layer 6, pressure-sensitive adhesive layer 7, surface resin layer 11, and dye transfer preventing resin layer 13 are the same as those described in embodiment 3. The focusing layer and the metal layer preferably further contain a self-destructing layer therebetween. The self-destructing layer is the same as described in embodiment 2. Further, it is preferable that the pressure-sensitive adhesive further comprises the self-destructing layer, and the pressure-sensitive adhesive layer is provided between the metal layer and the self-destructing layer. The self-destructing layer is the same as described in embodiment 3.

The printing layer 22 is a layer on which an image is formed in the thickness direction of the layer by the sublimable colorant, and has the same structure as the image-forming resin layer 12 except for the dye-containing dyed layer 50. The dye-dyed layer 50 is a layer in which an image is formed by the sublimable dyeing agent in the thickness direction of the layer.

(embodiment 10)

An example of a method 1 of making an image-bearing retroreflective sheeting for security applications according to the present invention is described below.

As described above, the method 1 for manufacturing a retroreflective sheet having an image for security use is characterized by comprising the steps of: printing is performed on a transfer paper using an ink containing a sublimable coloring agent, the image-forming surface of the transfer paper is brought into contact with the surface resin layer side of the retroreflective sheet for security of the present invention, and then a heating treatment is performed to sublimate the sublimable coloring agent to penetrate the surface resin layer to form an image in the image-forming resin layer, thereby obtaining a printing layer, and the transfer paper is removed. The retroreflective sheet for security use of the present invention used in the method 1 for producing the retroreflective sheet for security use with an image according to the present invention comprises the surface resin layer, the image-forming resin layer, the dye migration preventing resin layer, the adhesive layer, the high-refractive-index glass beads, the printing resin layer, the focus layer, the metal layer, and the pressure-sensitive adhesive layer in this order.

Examples of a method for printing on a transfer paper using an ink containing a sublimable colorant include an electrophotographic method, an electrostatic recording method, an ink jet method, and a thermal transfer method.

As the transfer paper, generally commercially available printing paper for inkjet, sublimation transfer paper, or the like can be used.

The step of bringing the image-formed surface of the transfer paper into contact with the surface resin layer side of the retroreflective security sheet of the present invention may be performed, for example, by bringing the printed surface of the transfer paper into contact with the surface resin layer side of the retroreflective security sheet, and removing air from between the transfer paper and the surface resin layer to sufficiently adhere the transfer paper and the surface resin layer.

As the heat treatment method, for example, a method of heating at about 100 to about 200 ℃ for several tens of seconds to several minutes using a vacuum heat crimping machine, a drying oven, a far infrared heating device, or the like can be used. By the heating, the sublimable coloring agent sublimates from the transfer paper, passes through the surface resin layer 11, and migrates to the image forming resin layer 12. Thereby, the dye is diffused in the image forming resin layer 12 to form an image. Therefore, an image can be formed in the thickness direction of the image forming resin layer 12, and the printing layer 22 including the dye-dyed layer 50 can be obtained.

(embodiment 11)

An example of a method 2 of making an image-bearing retroreflective sheeting for security applications according to the present invention is described below. In fig. 12, 9 is a releasable ink-receiving layer, 11 is a surface resin layer, 12 is an image-forming resin layer, 13 is a dye migration preventing resin layer, 2 is an adhesive layer, 3 is a high refractive index glass bead, 4 is a printing resin layer, 5 is a focus layer, 6 is a metal layer, and 7 is a pressure-sensitive adhesive layer.

As described above, the method of manufacturing the retroreflective image-bearing security sheet of claim 2 is characterized by comprising the steps of: the retroreflective security sheet of the present invention has a releasable ink-receiving layer (see fig. 12) formed on the surface resin layer, and the releasable ink-receiving layer has the following properties: the printing display can be carried out; a surface side which is in contact with the surface resin layer and which is absorptive for ink containing the sublimable coloring agent, and which is capable of forming an image in the image forming resin layer by sublimating the coloring agent through the surface resin layer by a heat treatment; and can be peeled off from the surface resin layer in a film state after the heat treatment; printing on the ink-containing layer using an ink containing a sublimable coloring agent; then, carrying out heating treatment to sublimate the sublimable coloring agent to penetrate through the surface resin layer, and forming an image in the image forming resin layer to obtain a printing layer; and peeling off the peelable ink-receiving layer. The retroreflective sheet for security use of the present invention used in the method 2 for producing an image-bearing retroreflective sheet for security use of the present invention comprises the surface resin layer, the image-forming resin layer, the dye migration preventing resin layer, the adhesive layer, the high-refractive-index glass beads, the printing resin layer, the focal layer, the metal layer, and the pressure-sensitive adhesive layer in this order.

The releasable ink containing layer 9 may be made of, for example, a hydrophilic resin. Examples of the hydrophilic resin include: urethane-based resin, acrylic-based resin, fluorine-based resin, unmodified and modified polyvinyl alcohol, polyester, acrylate urethane resin, vinyl acetate, maleic anhydride copolymer, sodium salt of alkyl ester, gelatin, albumin, casein, starch, SBR latex, NBR latex, cellulose-based resin, amide-based resin, melamine-based resin, polyacrylamide, polyvinylpyrrolidone, and a resin modified with a cation thereof, or a resin added with a hydrophilic group, and the like, and one or two or more of them may be used.

The releasable ink-receiving layer 9 may further contain a filler such as silica, clay, talc, diatomaceous earth, zeolite, calcium carbonate, alumina, zinc oxide, or titanium oxide.

The releasable ink containing layer 9 can be formed by applying a solution of the resin material to the surface resin layer 11 and heating and drying the applied solution.

As a method of printing on the ink containing layer 9 using an ink containing the coloring agent, thermal transfer, electrostatic printing, gravure printing, an inkjet method, and the like are preferable. Among these, the ink jet method is preferable as the printing method. This is because it is possible to easily perform full color printing. The on-demand printer is particularly preferable from the viewpoint of the use efficiency of the ink in terms of economy.

As the heating method, for example, a vacuum heat crimping machine, a drying oven, a far infrared heating device, or the like can be used, and heating can be performed at about 100 to about 200 ℃ for several tens of seconds to several minutes. The heating temperature is preferably 150-200 ℃. This allows the sublimable coloring agent to be sublimated efficiently in a shorter time, and is excellent in operability. Further, it is preferable that the surface of the printed ink containing layer 9 is dried to such a degree that it is dry to the touch before heating. Thus, the sublimable coloring agent can be uniformly diffused during the heat treatment.

The retroreflective sheet for security of the present invention can be formed by bonding a release material such as release paper or release film to the pressure-sensitive adhesive layer. The mold release material is not particularly limited, and a known mold release material can be used.

Examples

The following examples are more specifically given. In the following examples, "parts" means parts by weight. In addition, "%" represents weight%.

Example 1

First, a biaxially oriented polyester film was prepared as a surface layer 1, and a resin composition for forming a pressure-sensitive adhesive layer 2 was applied to the surface layer 1 so that the dry film thickness thereof became about 30 μm, and the film was dried by heating at 70 ℃ for 5 minutes to volatilize the solvent and form a pressure-sensitive adhesive layer 2, thereby obtaining a laminate of the surface layer 1 and the pressure-sensitive adhesive layer 2. The resin composition for forming the adhesive layer 2 at this time was formulated into 5 parts of Bekkolite M-6401-50 (oil-free alkyd resin, solid content 50%, manufactured by Dainippon ink chemical industries Co., Ltd.), 1.5 parts of Super Beckamine J-820-60 (butylated melamine resin, manufactured by Dainippon ink chemical industries Co., Ltd., solid content 60%), 0.5 part of Beckamine P-198 (curing catalyst, manufactured by Dainippon ink chemical industries Co., Ltd.), 70 parts of an olefin-based specific copolymer Elvaloy 551 (THF 25% solution manufactured by Sanjing Du Pont Polychemical Co., Ltd.), 15 parts of an acrylic resin (comprising styrene/methyl methacrylate/soft monomer, having a Tg of 50 ℃ and a hydroxyl value of about 14) (solid content of 45%) and 3 parts of an epoxy plasticizer O-130P (manufactured by Asahi Denka Co., Ltd.).

In this case, the pressure-sensitive adhesive layer 2 had a probe tack strength of 3gf (29.4 mN). The tack property is the tack strength measured under test conditions of a peel speed of 1 cm/sec, a measurement load of 9.8. + -. 0.1g (made of brass), a contact time of 1 second, a measurement environment of 23. + -. 2 ℃ and a relative humidity of 65. + -. 5% using a probe having a 5 mm. + -. stainless steel surface polished AA #400 and a mirror surface by an adhesion tester (manufactured by NICHIBAN K Ltd., based on ASTM D-2979).

The laminate sheet was rolled up, and then a printed resin layer 4 was formed by printing a mark on the adhesive layer 2 with a resin composition for forming a printed resin layer 4 by a gravure printing machine to obtain a laminate of the surface layer 1, the adhesive layer 2 and the printed resin layer 4. The resin composition for forming the printing resin layer 4 was formulated with 100 parts of a hydroxyl-containing acrylic resin (manufactured by Dainippon ink chemical industries, Ltd., solid content of 45%, solvent was xylene, butyl acetate, toluene, hydroxyl value of 45), 23 parts of an isocyanate prepolymer as a curing agent (manufactured by Dainippon ink chemical industries, Ltd., solid content of 75%, solvent was ethyl acetate, NCO content was 15%), and 10 parts of cellulose butyl acetate.

Then, the laminate was aged at room temperature for about 1 week to cure the printing resin layer 4. Then, the laminate was heated at 120 ℃ for 1 minute to develop adhesiveness in the pressure-sensitive adhesive layer 2. High refractive index glass beads (high refractive index glass beads having a refractive index of 2.23 and a particle diameter of 67 to 73 μm and containing titanium oxide as a main component) were scattered from the side of the printing resin layer 4 and adhered to the pressure-sensitive adhesive layer 2, and then heated at 140 ℃ for 5 minutes to embed and fix the high refractive index glass beads 3 only in the region having adhesive properties of the pressure-sensitive adhesive layer 2.

Then, the resin composition for forming the focal layer 5 was applied to the pressure-sensitive adhesive layer 2, the printing resin layer 4, and the high refractive index glass beads 3 of the laminate so that the dry film thickness became 16 μm, and the laminate was dried at 100 ℃ for 10 minutes and then dried at 140 ℃ for 10 minutes to volatilize the solvent, thereby forming the focal layer 5, thereby obtaining a laminate of the surface layer 1, the pressure-sensitive adhesive layer 2, the high refractive index glass beads 3, the printing resin layer 4, and the focal layer 5. The resin composition for forming the focal layer 5 was a polyurethane resin, 100 parts of BURNOCK L8-974 (manufactured by Dainippon ink chemical industries, Ltd.), and 10 parts of Super Beckamine J-820-60 (manufactured by Dainippon ink chemical industries, Ltd.).

Then, aluminum was deposited on the focal layer 5 of the laminate by vacuum deposition to a film thickness ofA laminate (retroreflective security sheet blank of the present invention) comprising a surface layer 1, a binder layer 2, high-refractive-index glass beads 3, a printing resin layer 4, a focus layer 5 and a metal layer 6 was obtained.

A mixed solution of about 100 parts of an acrylic pressure-sensitive adhesive FINETAC SPS-1016 (manufactured by Dainippon ink chemical industries Co., Ltd.), about 2 parts of a crosslinking agent FINETACTA-101-K (manufactured by Dainippon ink chemical industries Co., Ltd., curing agent chelate type for pressure-sensitive adhesive), about 2 parts of TINUVIN 900 and 0.2 part of an ultraviolet absorber TINUVIN 900 was applied to the silicon-coated surface of a biaxially oriented polyester release film (one surface of which was coated with a silicon coating and the other surface was subjected to antistatic treatment and annealing treatment, 50 μm thick, manufactured by Dirmin Du Pont Films, trade name A-31, and a shrinkage of 0.4% in the film winding direction when heated at 150 ℃ for 30 minutes) (release material 14), so that the dry film thickness was about 40 μm, and heat drying was performed at 100 ℃ for about 5 minutes, thereby forming the pressure-sensitive adhesive layer 7. Then, the pressure-sensitive adhesive layer 7 and the metal layer 6 of the laminate were bonded to each other so as to face each other, thereby obtaining a retroreflective sheet for safety of the present invention with a release material (see fig. 14).

When the retroreflective security sheet is viewed from the surface layer 1 side, the mark formed on the printed resin layer 4 can be recognized as a metallic color. When the retroreflective safety sheet is irradiated with light at night, the regions other than the mark portion are brightly lighted due to the retroreflective effect, and the mark portion is dark, so that the mark of the retroreflective safety sheet can be clearly recognized by the contrast.

Example 2

The adhesive layer 2 and the printing resin layer 4 were formed in the same manner as in example 1 except that a biaxially oriented polyester film (HSLF 8W, product of imperial Du Pont Films) having a shrinkage rate of 0.5% in the film winding direction when heated at 150 ℃ for 30 minutes was used instead of the biaxially oriented polyester film (surface layer 1), and the focal layer 5 was formed by inserting high refractive index glass beads 3. In addition, the aforementioned biaxially oriented polyester film is used not as the surface layer 1 but as the dye migration preventing resin layer 13. Thus, the resulting laminate is a laminate of the dye migration prevention resin layer 13, the adhesive layer 2, the high-refractive-index glass beads 3, the printing resin layer 4, and the focus layer 5.

Then, on the focal layer 5 of the laminate, additional release silicone resin was printed at equal intervals in the longitudinal direction and the width direction of the sheet using a gravure coater, and the english alphabet "office USE" was used as its predetermined pattern. The silicone resin for additional peeling used in this case was a mixed solution (XSR 7029A/XSR7029B/XSR 7029C/n-hexane 100/15/3/482, manufactured by GE toshiba silicone resin corporation). After the printing, the self-destructible layer 8 was formed by heating and drying at 140 ℃ for 60 seconds, and after aging at 25 ℃ for 24 hours, the metal layer 6 was formed on the self-destructible layer 8 in the same manner as in example 1, thereby obtaining a laminate of the dye migration preventing resin layer 13, the pressure-sensitive adhesive layer 2, the high refractive index glass beads 3, the printing resin layer 4, the focus layer 5, the self-destructible layer 8, and the metal layer 6. Then, the pressure-sensitive adhesive layer 7 and a release film (release material 14) were laminated on the metal layer 6 in the same manner as in example 1.

Then, a resin composition solution for forming the image forming resin layer 12 was applied onto the dye migration preventing resin layer 13 of the laminate so that the dry film thickness became about 30 μm, and the laminate was dried by heating at about 140 ℃ for about 10 minutes to form the pattern forming resin layer 12. The obtained image-forming resin layer 12 contains less than 5% of low-molecular-weight compounds having a molecular weight of about 1300 or less. The resin composition for forming the image-forming resin layer 12 had a formulation of about 100 parts of BURNOCK D6-439 (alkyd resin manufactured by Dainippon ink chemical industry Co., Ltd., hydroxyl value of solid content 140, and non-volatile content of about 80%), about 82 parts of BURNOCK DN-980 (polyisocyanate prepolymer manufactured by Dainippon ink chemical industry Co., Ltd., non-volatile content of about 75%), about 1 part of TINUVIN 900, and about 1 part of TINUVIN 292.

Then, the resin composition solution for forming the surface resin layer 11 was applied onto the image-forming resin layer 12 so that the dry film thickness became about 20 μm, and the surface resin layer 11 was formed by heating and drying at about 140 ℃ for about 10 minutes. Thus, a retroreflective sheet for security with a release material was obtained (see fig. 15).

The resin composition for forming the surface resin layer 11 was prepared from about 100 parts by weight of a solution of a copolymer of hexafluoropropylene/ethyl vinyl ether/VEOVA 9/monovinyl adipate 50/15/20/15 (weight ratio) as a fluororesin ("VEOVA 9": a trade name manufactured by japan epoxy resin company, vinyl ester of branched fatty acid, a mixed solvent of toluene/n-butanol 70/30 weight ratio, non-volatile content of about 50%), about 7.4 parts of sorbitan polyglycidyl ether having an epoxy equivalent of 170, about 0.6 parts of diazabicyclooctane, 12 parts of DICTON WHITE a-5260 (titanium oxide, solid content of about 75%), about 1 part of TINUVIN 292 (manufactured by Ciba Specialty Chemicals chemical company, benzotriazole-based ultraviolet absorber), about 1 part of tinvin 292 (manufactured by Ciba Specialty Chemicals company, hindered amine light stabilizers).

Example 3

Then, an image was printed on a transfer Paper (grade S-coat Paper) by a separately prepared piezoelectric printer (RJ-6000, manufactured by martial arts industries, inc.) as one of the ink jet methods. As the sublimation ink-jet ink used in this case, an ink-jet ink (6-color set of cyan, magenta, yellow, black, light cyan, and light magenta) manufactured by nippon and chemical industries containing a sublimation dye was used. The surface resin layer 11 of the retroreflective security sheet with a release material obtained in example 2 was brought into contact with the printing surface of the transfer paper, and superimposed thereon, and heat-pressure-bonded for about 7 minutes at a vacuum degree of 3.99 × 103Pa (30mmHg) and a set temperature of about 170 ℃ by using a heat vacuum applicator (VacuSeal 4468 manufactured by HUNT EUROPE corporation). As a result, the image such as the barcode to which the individual information such as the color vehicle, the release date, the official seal, and the postal code is inputted, which is printed on the transfer paper, is diffusion-dyed on the image forming resin layer 12 of the retroreflective security sheet to obtain the print layer 22, and then the transfer paper is peeled to obtain the retroreflective image-bearing security sheet with the release material (see fig. 16).

Then, the release film (release material) is peeled off, and the retroreflective sheet with an image for security is stuck to the rear window of a vehicle from the outside of the vehicle, whereby a bar code or the like of individual information such as a color vehicle, a release date, a official seal, a postal code or the like can be clearly seen regardless of day and night (irradiated with light at night). And the mark can be clearly seen no matter day and night. Further, a barcode reader may read a barcode into which individual information is input. When the retroreflective sheet having an image for security is peeled off, peeling occurs between the printed portion of "office USE" and the metal layer on the glass surface of the rear window, and the character of "office USE" appears on the glass surface of the rear window. The "office USE" is left on the peeled image-bearing retroreflective sheet in the form of a metal layer free characters, and it can be confirmed at a glance that the image-bearing retroreflective sheet is peeled off from the rear window. Further, information on the peeled image-bearing retroreflective sheet for security cannot be rewritten and cannot be reused. Even when the retroreflective sheet with an image for security was adhered to a glass plate and left to stand at 65 ℃ for 500 hours, no bleeding occurred at the edges of the image, and the sharpness of the image did not disappear.

Example 4

First, the surface resin layer 11 is formed. The following resin composition for forming the surface resin layer 11 was applied to a polyester film (support film) so that the dry film thickness was about 20 μm, and the surface resin layer 11 was formed on the support film by heating and drying at about 140 ℃ for about 10 minutes. The resin composition for forming the surface resin layer 11 was formulated with about 100 parts of FLUONATE K-703 (manufactured by Dainippon ink chemical industries, Ltd., weight average molecular weight 40000, hydroxyl value 72 in solid content, and non-volatile content about 60%) (fluorine-containing resin), about 25 parts of BURNOCK DN-950 (curing agent), about 1 part of TINUVIN 900 (ultraviolet absorber), 15 parts of DICTON WHITE A-5260 (titanium oxide, solid content 75%), and about 1 part of TINUVIN 292 (antioxidant).

Then, on the surface resin layer 11, a polycarbonate-based non-yellowing polyurethane resin NY-331 (manufactured by Dainippon ink chemical industries, Ltd., nonvolatile content: about 25%, solvent DMF, 100% modulus: about 55 kg/cm)²) The coating was performed, and the coating was dried by heating at about 140 ℃ for about 10 minutes to a dry film thickness of about 20 μm, thereby producing the image-forming resin layer 12. The low molecular weight compound having a molecular weight of about 1300 or less contained in the obtained image-forming resin layer is less than 3%.

Then, a resin composition obtained by mixing about 100 parts of the acrylic copolymer (a-2) synthesized in reference example 2 and about 50 parts of BURNOCKDN-950 (75% of nonvolatile content, manufactured by Dainippon ink chemical Co., Ltd.) was applied onto the image-forming resin layer 12 so that the dry film thickness was about 15 μm, and the mixture was dried by heating at about 140 ℃ for about 10 minutes to prepare a dye migration-preventing resin layer 13.

The adhesive layer 2 was formed on the dye migration preventing resin layer 13 in the same manner as in example 2. Then, a printed resin layer 4, embedded high refractive index glass beads 3, a laminated focus layer 5, a self-adhesive layer 8, a metal layer 6, a pressure-sensitive adhesive layer 7, and a release film (release material) were formed in the same manner as in example 2 to obtain a retroreflective security sheet with a release material (see fig. 15).

Example 5

The surface resin layer 11 of the retroreflective sheet with a release material for safety use obtained in example 4 was coated with FLUONATE FEM-600 (solid content: 45%) manufactured by Dainippon ink chemical industries, which is an aqueous fluorine-containing resin so that the dry film thickness was about 15 μm, and the sheet was dried by heating at about 110 ℃ for about 5 minutes. Thereafter, MZ-100 (amorphous silica, a mixture of polyurethane and a vinyl resin, 15% in solids, and about 56% in porous pigment content in solids) manufactured by Hippon pine oil and fat Co., Ltd. as an inkjet receptor was applied onto the dried film so that the dried film thickness was about 30 μm, and the dried film was heated and dried at about 110 ℃ for about 5 minutes to form a releasable ink-receiving layer 9 (see FIG. 17).

In the releasable ink containing layer 9, an image was printed in the same manner as in example 3. Then, a hot air dryer (Fine Oven DF6L manufactured by Yamato science) was set at about 170 ℃, heat treatment was performed for about 7 minutes to diffuse and penetrate an image such as a barcode to which individual information such as a color vehicle, a release date, a official seal, and a postal code of the owner was input, and the image was transferred to obtain a printed layer, and then the releasable ink receiving layer 9 was peeled off in a state of a release film to obtain a retroreflective sheet with an image for security use with a release material (see fig. 16).

Then, the release film (release material) is peeled off, and the retroreflective sheet with an image for security obtained from the outside of the vehicle is stuck to the rear window of the vehicle, so that the bar code or the like to which individual information such as a color vehicle, a release date, a official seal, a postal code or the like is input can be clearly seen regardless of the day and night (irradiated with light at night). Further, the mark on the image reflection sheet for security can be clearly seen even in day and night. Further, a barcode reader may read a barcode into which individual information is input. When the retroreflective sheet having an image for security is peeled off, peeling occurs between the printed portion of "office USE" on the glass surface of the rear window and the metal layer, and the character "office USE" appears on the glass surface of the rear window. The "office USE" remains as a detachment character of the metal layer on the peeled image-bearing retroreflective security sheet, and it can be confirmed at a glance that the image-bearing retroreflective security sheet is peeled off from the rear window. Further, information on the peeled image-bearing retroreflective sheet for security cannot be rewritten and cannot be reused. Even when the retroreflective sheet with an image for security was adhered to a glass plate and left to stand at 65 ℃ for 500 hours, no bleeding occurred at the edges of the image, and the sharpness of the image did not disappear.

Comparative example 1

A retroreflective security sheet with a release material was obtained in the same manner as in example 2, except that the formulation of the resin composition of the image-forming resin layer 12 in example 2 was changed as follows.

The formulation of the resin composition of the image-forming resin layer 12 is: about 100 parts of BURNOCK D6-439 (alkyd resin manufactured by Dainippon ink chemical industries, hydroxyl value in solid state 140, and non-volatile matter 80%), about 82 parts of BURNOCKDN-980 (polyisocyanate prepolymer manufactured by Dainippon ink chemical industries, non-volatile matter 75%), about 1 part of TINUVIN 900, about 1 part of TINUVIN 292, and 40 parts of polyester plasticizer D620 (manufactured by J-PLUS, molecular weight about 800) as a polymer plasticizer. The low-molecular-weight compound contained in the obtained image-forming resin layer and having a molecular weight of 1300 or less was about 22%.

The completed retroreflective security sheet with a release material was diffusion-dyed with a barcode or the like, to which individual information such as color cars, release dates, official seal, postal code, and the like was input, into the image-forming resin layer 12 of the retroreflective security sheet, and the image was transferred to obtain a printed layer, in the same manner as in example 3. The release film (release material) of the obtained retroreflective sheet with image for security with release material was peeled off, and after the sheet was attached to the rear window of a vehicle from the outside of the vehicle, the information could not be read by a barcode reader. This is considered to be because the sublimation dye at the edges of the bars of the barcode bleeds out, and as a result, the sharpness of the stripes is impaired, and therefore the barcode reader cannot read the stripes. When the retroreflective sheet for security was adhered to a glass plate and left to stand at 65 ℃ for 200 hours, the edge of the image was discolored, and the sharpness of the image was deteriorated.

Comparative example 2

A retroreflective sheet for safety use with a release material was obtained in the same manner as in example 4, except that the step of preparing the dye transfer preventing resin layer 13 of example 4 was omitted.

In the retroreflective security sheet with a release material, a barcode or the like to which individual information such as a color vehicle, a release date, a official seal, a postal code or the like is input is diffusion-dyed into the image-forming resin layer 12 of the retroreflective security sheet in the same manner as in example 5, and an image is transferred to obtain a printed layer. The obtained retroreflective sheet with image for security with release material is peeled off from the release film, and is attached to the rear window of a vehicle from the outside of the vehicle, and then information can be read with a barcode reader through the glass of the rear window. When the retroreflective sheet with an image for security was adhered to a glass plate and left to stand at 65 ℃ for 200 hours, the edge of the image was discolored, and the sharpness of the image was deteriorated. In addition, the sublimation dye bleeds out at the edges of the bars of the bar code, and as a result, the sharpness of the stripes is impaired, and information cannot be read by the bar code reader.

The retroreflective sheet for security of the present invention is adhered to the outside of a window glass of a vehicle or the like, has a function of displaying information of the vehicle or the like, and is also suitable for use in applications of preventing forgery of a vehicle license plate.

Claims

1. A retroreflective sheet for security which comprises a surface layer, an adhesive layer, high-refractive-index glass beads, a printing resin layer, a focusing layer, a metal layer, and a pressure-sensitive adhesive layer in this order,

the printing resin layer is formed with a mark,

the adhesive layer is provided with the high-refractive-index glass beads,

the arrangement position of the high refractive index glass beads and the position of the printing resin layer do not overlap when viewed from the surface layer in the thickness direction of the retroreflective security sheet,

the printing resin layer is formed from a composition containing a normal temperature curable resin as a main component.

2. The retroreflective security sheeting of claim 1, wherein the adhesive layer is formed from a composition comprising a thermosetting resin.

3. The retroreflective security sheeting of claim 1, further comprising a self-destructive layer between the focal layer and the metal layer.

4. The retroreflective security sheeting of claim 3, wherein the self-destructive layer is formed from a resin composition that has low adhesion to the metal layer.

5. The retroreflective security sheeting of claim 1, further comprising a self-destructive layer, wherein the pressure sensitive adhesive layer is disposed between the metal layer and the self-destructive layer.

6. The retroreflective security sheeting of claim 5, wherein the self-immolative layer is a holographic image or diffraction grating containing film or a brittle or carrier film that has been subjected to a regular or irregular release treatment.

7. The retroreflective security sheeting of claim 1, wherein the surface layer and the adhesive layer are formed from the same resin composition.

8. The retroreflective security sheeting of claim 1, which is colored by heating to allow a sublimating colorant to penetrate into the image-forming resin layer, wherein the surface layer comprises, in order from the surface: a surface resin layer which has a weak affinity with the sublimable coloring agent and allows the sublimable coloring agent to pass therethrough, an image forming resin layer having an affinity with the sublimable coloring agent, and a dye migration preventing resin layer which prevents migration of the sublimable coloring agent.

9. The retroreflective sheet for security according to claim 8, wherein the dye migration preventing resin layer is a resin layer containing a vinyl resin having a glass transition temperature Tg of 70 ℃ or higher and an SP value of 9.0 or higher as a main component.

10. The retroreflective security sheeting of claim 8, wherein the dye migration preventing resin layer has a film thickness of 1 μm to 100 μm.

11. The retroreflective security sheet according to claim 8, wherein the dye migration preventing resin layer is a biaxially oriented film stretched by 10% or more in each of a winding direction and a width direction.

12. The retroreflective security sheet according to claim 11, wherein the biaxially oriented film has a shrinkage rate in a winding direction of 1.0% or less when heated at 150 ℃ for 30 minutes.

13. The retroreflective security sheet according to claim 8, wherein the image-forming resin layer is a resin layer containing 0 to 20 wt% of a low-molecular-weight compound having a molecular weight of 1300 or less.

14. A retroreflective security sheet blank for use in the retroreflective security sheet of claim 1, comprising a surface layer, a binder layer, high-refractive-index glass beads, a printing resin layer, a focus layer and a metal layer in this order,

wherein the printed resin layer is formed with a mark,

the adhesive layer is provided with high-refractive-index glass beads,

the arrangement position of the high refractive index glass beads and the position of the printing resin layer do not overlap when viewed from the surface layer in the thickness direction of the retroreflective security sheet blank,

15. A method of making the security retroreflective sheeting of claim 1 comprising the steps of:

an adhesive layer is laminated on the surface layer,

printing on the adhesive layer to form a printed resin layer,

curing the printing resin layer at a normal temperature,

heating the adhesive layer until a temperature at which the adhesive layer exhibits adhesiveness is reached,

embedding high refractive index glass beads in a portion of the adhesive layer where the printing resin layer is not formed,

laminating a focus layer on the adhesive layer, the printing resin layer, and the high refractive index glass beads,

forming a metal layer on the focal layer,

forming a pressure sensitive adhesive layer on the metal layer.

16. The method of making a retroreflective security sheeting of claim 15 wherein the surface layer comprises, in order from the surface: a surface resin layer which has a weak affinity with a sublimable coloring agent and allows the sublimable coloring agent to pass therethrough, an image forming resin layer having an affinity with the coloring agent, and a dye migration preventing resin layer which prevents migration of the sublimable coloring agent,

the manufacturing method further includes a step of laminating the adhesive layer on the dye transfer prevention resin layer.

17. A retroreflective security sheet having an image thereon, comprising in order:

a surface resin layer which has a low affinity with the sublimable coloring agent and allows the sublimable coloring agent to pass therethrough,

A printing layer having affinity with the sublimable coloring agent and having an image formed in the thickness direction of the layer by the sublimable coloring agent, and a method for producing the printing layer,

A dye migration preventing resin layer for preventing migration of the sublimable coloring agent,

An adhesive layer,

High refractive index glass beads,

A printing resin layer,

A focus layer,

A metal layer, and

a layer of a pressure-sensitive adhesive,

wherein the printed resin layer is formed with a mark,

the adhesive layer is provided with the high-refractive-index glass beads,

wherein the arrangement position of the high refractive index glass beads and the position of the printing resin layer do not overlap when viewed from the surface resin layer in the thickness direction of the image-bearing retroreflective sheet for security,

18. A security imaged retroreflective sheeting as defined in claim 17, further comprising a self-destructive layer between the focal layer and the metal layer.

19. A method of making the security image-bearing retroreflective sheeting of claim 17 comprising the steps of:

printing on transfer paper using an ink containing a sublimable colorant;

contacting an image-forming surface of the transfer paper with the surface resin layer side of the retroreflective security sheet according to claim 8;

then heating to make the sublimable coloring agent sublime and permeate through the surface resin layer to form an image in the image forming resin layer, thereby obtaining a printed layer; and

and removing the transfer paper.

20. A method of making the security image-bearing retroreflective sheeting of claim 17 comprising the steps of:

forming a release ink receiving layer on the surface resin layer of the retroreflective security sheeting of claim 8, the release ink receiving layer having the following properties: the printing display can be carried out; a surface side in contact with the surface resin layer is absorptive for ink containing the sublimable coloring agent, and is capable of forming an image in the image forming resin layer by sublimating the sublimable coloring agent and penetrating through the surface resin layer by a heating treatment; being peelable from the surface resin layer in a film state after the heat treatment;

printing on the releasable ink-receiving layer using an ink containing a sublimable colorant;

and peeling off the peelable ink receiving layer.