JP5168188B2 - True / false judgment with color variable function - Google Patents

Description

The present invention includes gift vouchers such as gift certificates, securities, stock certificates, various cards such as credit cards, prepaid cards, ID cards, tickets, banknotes, passports, identification cards, public competition voting tickets, video software, PC software, etc. The present invention relates to a true / false determination unit with a color variable function that is excellent in anti-counterfeiting effects and constitutes various anti-counterfeiting objects such as authenticity determination seals used in (hereinafter referred to as security objects).
In general, electromagnetic waves can be classified as ultraviolet rays, visible rays, and infrared rays. In the present invention, the visible light region, that is, the visible region is 360 nm to 830 nm (JIS Z8120), and light having a shorter wavelength than the visible light is used. Ultraviolet light, and that region is the ultraviolet region. Further, light having a wavelength longer than that of visible light is infrared, and the region is an infrared region.
In general, the visible region is “purple”: 380 nm to 450 nm, “blue”: 450 nm to 495 nm, “green”: 495 nm to 570 nm, “yellow”: 570 nm to 590 nm, “orange”: 590 nm to 620 nm, “red”: 620 nm Although it is divided into ˜750 nm, the change is continuous, and this classification is an example.
In addition, the ultraviolet region in the present invention refers to a region whose range is determined from the characteristics of the pigment of the present invention, and refers to one region in a general near ultraviolet region: 380 nm to 200 nm. Furthermore, the infrared region in the present invention refers to a region whose range is determined based on the characteristics of the pigment of the present invention, but refers to one region in a general near infrared region: 830 nm to 2500 nm.
In the present invention, “the incident angle of light to be observed”, that is, “the light to be observed whose angle with respect to the reference direction is a direction perpendicular to the color variable ink layer surface” is “0 ° to 70 °”. When observing the color variable ink layer surface, according to the incident angle, “the wavelength of the selectively reflected light” (the light exiting in the regular reflection direction is selected from the wavelength components of the incident light) Meaning that only a part of the wavelength component is changed.) A pigment having a property of changing, that is, a color variable ink layer containing a pearl pigment, an effect pigment, a liquid crystal pigment, etc. The present invention relates to an authenticity determination body with a color variable function having a hologram forming layer for reproducing a hologram image (including diffracted light).

Pearl pigments are natural mica flakes (also called mica flakes) coated with a transparent metal oxide. Effect pigments are natural alumina flakes, artificially synthesized alumina flakes, silicon oxide flakes (silica). Flakes), borosilicate glass flakes and the like are coated with a transparent metal oxide.
Usually, when the color variable ink layer is observed and visually determined, it is performed at an angle of 0 to 70 degrees with respect to the reference direction. Observation at 80 to 90 degrees is not performed unless otherwise specified.
As the liquid crystal pigment, a three-dimensional cross-linking substance having a liquid crystal structure having a chiral phase can be used. In particular, a cholesteric liquid crystal pigment having wavelength-selective reflected light is suitable.
Cholesteric liquid crystals are induced by adding a small amount of optically active substances (chiral agents) to nematic liquid crystals, and have a constant refractive index change in the liquid crystal layer by having a helical structure with a constant period with respect to the reference direction. Layers are stacked. The multilayer structure having this refractive index distribution has the property of reflecting incident light for observation at a predetermined angle after selecting the wavelength. The wavelength of the selectively reflected light is determined by the refractive index value (distribution) of the cholesteric liquid crystal and the thickness of the refractive index changing layer, that is, the interval between layers of the multilayer structure.
The cholesteric liquid crystal is formed into flakes (this state is referred to as a cholesteric liquid crystal pigment), and a color variable ink composition is obtained by the same method as that for the pearl pigment.
The color variable ink layer is formed on the surface of a plastic film or the like by using the color variable ink composition, or an appropriate method such as various printing methods directly on the surface of the security object. It is formed by.
A hologram forming layer is provided on the color variable ink layer or through a transparent substrate, and only the light transmitted through the color variable ink layer includes a hologram image, and the hologram reproduction direction is different from the regular reflection direction. By utilizing the property of forming the reconstructed image in the direction, light other than the selectively reflected light of the color variable ink layer is derived in a direction different from the selectively reflected light, and the color of the selectively reflected light is made vivid. At the same time, a hologram reproduction image having a unique color tone is reproduced to provide a true / false determination unit with a color variable function having a high anti-counterfeiting property.
In addition, a holographic relief formed on the color variable ink layer itself has the same effect.

(Main applications)
The main use of the true / false judgment body with the color variable function of the present invention is to prevent damages to the card holder or the card company when used forgery prevention, specifically credit cards. What can be given, identification card such as driver's license, employee ID card, membership card, admission ticket for entrance examination, passport, banknote, gift certificate, point card, stock certificate, securities, lottery ticket, horse ticket, passbook Tickets, passports, air tickets, admission tickets for various events, play tickets, prepaid cards for transportation and various telephones.
All of these are information records that hold information of economic or social value, identity identification, etc., and can identify the authenticity of the record itself for the purpose of preventing damage caused by forgery. Although it is desired to have a function, the present invention is applied to a method in which the confirmation method is visual and it is particularly desired to have a function to prove the authenticity of the visual determination.
In addition to the uses described above, expensive products such as luxury watches, luxury leather products, precious metal products, jewelry, etc., often referred to as luxury brand products, or storage boxes for these expensive products And cases can also be forged. In addition, mass-produced products of famous brands, such as audio products, electrical appliances, etc., or tags that are hung on them are also subject to forgery.
Furthermore, a storage body in which music software, video software, computer software, game software, or the like, which is a copyrighted work, or cases thereof can also be forged. In addition, it is desirable that products such as printer toner, paper, and the like in which supplies to be replaced are limited to genuine materials have a function of identifying their authenticity for the purpose of preventing damage caused by forgery.
A forgery prevention body or the like that can be visually judged is added to these things in a form such as sticking, and the authenticity of the security object is proved by the visual judgment.
In the present specification, “ratio”, “part”, “%” and the like indicating the composition are based on mass unless otherwise specified, and the “/” mark indicates that they are integrally laminated.

(Background technology)
Conventionally, in order to prevent counterfeiting of this kind of cash vouchers, forgery prevention technology is provided in which a color variable printing layer whose color changes depending on the viewing angle is used. Such a color variable printing layer is a color variable ink whose color changes depending on the viewing angle, such as pearl ink, and is formed by printing or the like. The ink whose color changes includes a pigment that multi-reflects light, and the color appears to change due to interference of light reflected by the pigment. Therefore, the color change effect increases as the amount of light reflected by the pigment increases. Therefore, the color variable printing layer is often printed by stencil printing such as screen printing or intaglio printing such as gravure printing so that the thickness of the color variable printing layer is increased so that the number of pigments that multiple reflect light is increased. .
Specifically, forgery prevention that provided a color variable printing layer such as pearl printing on printing media such as gift certificates, stock certificates, etc., and concealed a part of the color variable printing layer in a pattern so as not to be visible, forming specific information Print media has been proposed. (For example, refer to Patent Document 1).
This print medium has a feature that the color tone of the medium base material and the color tone of the specific information appear to be synchronized. However, general pearl ink itself can be obtained unless its optical performance is specified, and if it is a normal printing manufacturer, pearl ink is obtained and matte ink is printed thereon. Thus, it is possible to make a similar printed matter.

Therefore, in order to further improve anti-counterfeiting, a color variable printing layer whose color changes depending on the viewing angle, and a photoreactive printing layer that emits fluorescence by irradiation of ultraviolet rays or infrared rays on the color variable printing layer are provided in a pattern. At least a portion of the printed portion using an anti-counterfeit printing medium (for example, see Patent Document 2), or an anti-counterfeit ink composition containing at least a pearl pigment and a fluorescent pigment whose color tone is changed by ultraviolet irradiation or infrared irradiation. However, forgery prevention printed matter (for example, refer to Patent Document 3) having a configuration in which a single color or a plurality of colors are printed is known.
In addition, as another pigment having pleochroicity depending on the observation angle as described above, for example, a composition comprising a cholesteric liquid crystal, a three-dimensional crosslinkable resin, a photoinitiator, and the like is applied to a plastic film by a doctor. There is a method of using a liquid crystal pigment or the like obtained by aligning and forming by a shearing gradient at the time of peeling, and then peeling and crushing from a plastic film. (For example, refer to Patent Document 4).
The above-mentioned pigment has a feature that the hue varies depending on the viewing angle and the reflected light is circularly polarized. Depending on the normal copying means, it is not possible to make the duplicates have such optical characteristics. Therefore, it is very effective to use liquid crystal pigments for preventing counterfeiting of securities and credit cards. In addition, since the hue changes depending on the observation angle, there is a feature that an excellent design can be obtained.

JP 2000-006564 A JP 2002-274000 A JP 2002-285061 A JP 1994-220350

However, in these pigments showing color variability, the basic principle of color variability is that for pearl pigments and effect pigments, natural mica flakes (mica flakes), alumina flakes, silica flakes, On the surface of the silicate glass flakes, a transparent metal oxide thin film having a thickness smaller than the visible light wavelength and a refractive index larger than those of the transparent substrate is formed, and the light incident on the pigment is multiplexed in the thin film. The wavelength of the reflected light is made selective by reflection and the interference phenomenon.
In other words, when the light is multiple-reflected, the multiple reflected light causes an interference phenomenon, and the reflected light wavelength is transparent due to the fundamental property of light that concentrates the reflected light wavelength and increases its intensity. It is automatically determined depending on the refractive index value and thickness of the metal oxide thin film, and the “color changes” and the “change pattern” (degree of change, range of change, etc.) are also uniquely determined.
Due to the effect of this multiple reflection, the “change pattern” is as follows. That is, it enters the thin film perpendicularly (“angle 0 °” with respect to the reference direction), and is incident perpendicularly, for example, at an angle of 45 degrees, and again 45 in the opposite direction. The wavelength of light that is selectively reflected differs greatly from the case of light that reflects at a degree, and “45-degree reflected light (after 45 degrees incidence)” differs from “vertically reflected light (after perpendicular incidence)” Theoretically, the wavelength value is 0.71 times (from cos 45 ° / cos 0 ° ≈0.71).
That is, in a certain pigment, if the vertically reflected light (after normal incidence) is 700 nm (red), the 45 degree reflected light (after 45 degrees incident) becomes 490 nm (blue). A so-called “blue shift” occurs.
This is a basic property of “transparent thin film” (transparent metal oxide thin film in pearl pigment), and the color change is monotonously changed from long wavelength to short wavelength according to this theory (“blue shift”). To do.
That is, the color of the vertical reflected light and the color of the 45 ° or 70 ° reflected light are uniquely determined by the thickness of the transparent metal oxide thin film layer, the refractive index value, and the like. It is the same. Therefore, even when the above-described various color variable inks are used, the color change situation is the same. As a result of the popularization of these pigments, the same color change is confirmed. Therefore, it can no longer be said that it has anti-counterfeiting properties.
In addition, the liquid crystal pigment has a refractive index distribution in the liquid crystal itself, and this refractive index distribution has the same function as the above-described thin film, and therefore exhibits the same selective reflectivity. Accordingly, the wavelength change of the reflected light becomes “blue shift” as in the thin film.
As described above, all the “color variable inks” are “blue shifted” at the same rate of change, so even if various color variable inks are applied to the security object, they are visually observed. As described above, the appearance is almost the same, and the security is somewhat inferior in terms of the anti-counterfeit effect by visual determination.

Accordingly, the present invention has been made to solve such problems. Its purpose is
It is an object of the present invention to provide a color variable ink that exhibits a color change not found in conventional color variable inks.
That is, the “blue shift” that is the basic principle of the transparent thin film is not performed, for example, “blue shift” is exhibited as vertical reflected light, and “red” is exhibited as reflected light near 70 degrees. Provided is a true / false determination body with a color variable function in which a color variable ink layer to be presented and a hologram forming layer are laminated.

To solve the above problem,
The first aspect of the present invention is:
According to the incident angle of the light to be observed, it is a true / false determination body with a color variable function comprising a color variable ink layer containing a pigment whose wavelength of light to be selectively reflected and a hologram forming layer,
A pigment in which the wavelength of the selectively reflected light of the pigment shifts from a visible region of 500 nm or less to an ultraviolet region when the incident angle changes from 0 degrees to 70 degrees;
It includes a pigment that shifts from an infrared region to a visible region of 500 nm or more.
According to a first aspect of the invention,
According to the incident angle of the light to be observed, it is a true / false determination body with a color variable function comprising a color variable ink layer containing a pigment whose wavelength of light to be selectively reflected and a hologram forming layer,
A pigment in which the wavelength of the selectively reflected light of the pigment shifts from a visible region of 500 nm or less to an ultraviolet region when the incident angle changes from 0 degrees to 70 degrees;
There is provided a true / false determination object having a color variable function, which includes a pigment that shifts from an infrared region to a visible region of 500 nm or more.
Pearl pigments, effect pigments, etc. are fine flakes and theoretically calculated when the flat surface of the flake is parallel to the surface formed by the color variable ink layer when it becomes a color variable ink layer. However, when the flakes are directed in various other directions, the incident angle and the reflection angle of the light on the transparent oxide thin film formed on the flakes are different. As a result, various colors of reflected light (hereinafter referred to as scattered light) are generated in directions other than a predetermined reflection angle.
Further, the incident light may pass through a plurality of flakes and finally appear as reflected light. The shape of the flake itself, the properties of the flake surface, the refractive index and its distribution also affect the reflection on the flake surface and the attenuation of transmitted light.
However, light that has passed through a plurality of flakes has a large attenuation, has little effect on visual observation, and an angle at which the light is regularly reflected with respect to the incidence of light at a predetermined incident angle. Since only the light that has passed through a predetermined path reaches the reflected light that comes out of the light, the wavelength selection process is limited, and as a result, only light having a predetermined wavelength is reflected.
In order to ensure the intensity of light of this predetermined wavelength and reduce unnecessary scattered light, the flake shape is flat, the flake surface is smooth, the transparent oxide thin film has a uniform thickness, and the color variable ink layer The flakes that are parallel to the ink layer forming surface have a large proportion, and the light incident on the ink layer is reflected only by one or two flakes, and the ink is reflected as reflected light. Design to come out of the layer.

In the visual observation, since this scattered light becomes an obstacle to determination, the formation method is devised so that the flakes are parallel to the surface formed by the color variable ink layer when the color variable ink layer is formed. For example, a flat pigment (a disk shape with a flatness ratio of 2 to 5. The flatness ratio is an ellipsoid, and is a value obtained by dividing the major axis length by the minor axis length. When the flatness ratio is 5 or more, the pigment is deformed in the inking process and the scattered light also increases.), And the pigment size (average particle diameter) is, for example, 10 μm, When the thickness of the color variable ink layer after drying is ½ or less, the ratio of the pigment in the inclined state decreases, and many of them are parallel to the color variable ink layer. Furthermore, as a method of forming the color variable ink layer, as in blade coating, a printing pressure is applied in the coating direction, and during coating, a color variable ink layer is formed with a low viscosity, and the time for flakes to overlap with its own weight is set. After securing, the scattered light can be reduced by making various solvent evaporations at the time of drying and suppressing the flakes being pushed up during the evaporation.
Accordingly, when composing the ink composition, depending on the printing method employed, the solvent ratio is 50% to 90%, and the solid content (color variable ink layer forming component, consisting of pigment, resin and additive). Of these, the pigment ratio is 10% to 50%. In order to obtain a predetermined reflected light intensity, mixing of 10% or more is necessary. However, if it exceeds 50%, the interaction between pigments such as aggregation between pigments works strongly, and the surface of the color variable ink layer is formed. It becomes difficult to become parallel to.
When the color variable ink layer forming method is an ultraviolet ray curing method or an electron beam curing method, the color variable ink can be made to have a low viscosity and the color variable ink layer is cured without using almost any solvent. Since it is possible to secure the time until the flakes are made, it becomes easy to perform the process of aligning the flakes, such as securing the time of overlapping with its own weight, or performing a calendar process.
Since the flakes used in the present invention are transparent, they are particularly suitable for these forming methods using ionizing radiation.

Of course, the affinity between the pigment and the resin is important. The better the adhesiveness, the simpler the reflection / transmission (refraction) at the pigment / resin interface, and the less the scattered light. When the surface of the pigment is not a smooth surface, complicated reflection and transmission (refraction) occur at the interface, and light travels in various directions. Since the reflection at this interface is a portion that does not contribute to the wavelength selectivity due to multiple reflection in the transparent metal thin film layer of the present invention, it is desirable that this surface simply transmit. That is, it is desirable that the surface is smooth, has little reflected light, and that almost all incident light simply passes through this surface.
For this purpose, it is desirable that the difference in refractive index between the resin and the transparent metal thin film is small. For example, for a transparent metal thin film having a refractive index of 1.80 or more, the refractive index of the resin is 1.40 or more, preferably Is preferably 1.60 or more.
However, since there is no transparent resin having a refractive index near 1.80, conversely, a transparent metal thin film having a low refractive index, for example, a refractive index of 1.50 is used, and a resin having the same refractive index is adopted. Thus, unnecessary reflection at the interface between the resin and the transparent metal thin film can be almost eliminated.
Examples of the resin include polymethyl acrylate (n = 1.47), polyvinyl acetate (n = 1.47), polyvinyl chloride / vinyl acetate (n = 1.54), melamine resin (n = 1.56), An epoxy resin (n = 1.61), a phenol resin (n = 1.60), or a mixture thereof can be used as appropriate.
The optimum solvent is selected depending on the color variable ink layer forming method.
As the solvent, esters, ethers, alicyclic hydrocarbons, aliphatic hydrocarbons, aromatics, alcohols, and the like and mixtures thereof are used.
These are classified into low boiling point solvents (boiling point 100 ° C or lower), medium boiling point solvents (boiling point 100 ° C to 150 ° C), and high boiling point solvents (boiling point 150 ° C or higher) according to the boiling point. Adjust the flakes to be parallel to the surface of the color variable ink layer, such as mixing with boiling point solvents and devising to gradually dry out while suppressing rapid solvent volatilization.
Furthermore, in consideration of transparency, various additives, dispersants, leveling agents, lubricants, plasticizers, coupling agents, antifoaming agents, ultraviolet absorbers, various curing accelerators and the like are used.
The color variable ink forming method is used in various methods such as offset printing, letterpress printing, gravure printing, nozzle printing, curtain coat printing, silk screen printing, intaglio printing, inkjet printing, etc. in order to fully demonstrate the functions of the present invention. The solvent composition, ink viscosity adjustment and drying / curing methods can be devised.
Of course, in consideration of the environment, it is also suitable to use a water-based ink composition using a water-soluble resin such as polyvinyl alcohol.

As pearl pigments and effect pigments,
Natural mica flakes (mica flakes), etc., pigments coated with metal oxides such as titanium oxide and iron oxide, synthetic alumina flakes (particle size 1-30 μm, thickness 0.5 μm-5 μm), synthetic silica flakes (particle size 5-30 μm, thickness 0.5 μm-5 μm), borosilicate glass flakes coated with titanium oxide (particle size 10-30 μm, thickness 0.5 μm-5 μm), synthetic mica flakes (aluminum oxide, magnesium oxide, silicon dioxide, A pigment in which a metal oxide such as titanium oxide or iron oxide is coated (coated with 50 nm to 400 nm) on a fluorine compound or the like can be used.
Artificially synthesized materials are preferable because they have a sharp particle size distribution with little variation in particle size, a smooth surface, and a uniform shape.
Moreover, if the thickness of the bright metal thin film formed on the flake surface is not a predetermined thickness, the wavelength of light reflected to a predetermined reflection angle is shifted. For this reason, the variation in the thickness of the transparent metal thin film on the flakes needs to be within ± 20%, and further within ± 10%. At 20%, the wavelength variation is almost 17%. At 10%, it is about 10%.
Of course, this wavelength changes depending on the refractive index variation of the transparent metal thin film, but the accuracy of formation by the liquid phase method or the CVD method (compound vapor deposition method) is very high, which affects the color change of the present invention. There is not much variation.
When this transparent metal thin film is made of titanium dioxide (the refractive index changes depending on the degree of oxidation) and the thickness is 90 nm to 100 nm, the vertical reflected light becomes the infrared region, and the color changes even when observed from the vertical direction. Although it cannot be recognized, red reflected light (“red”: 620 nm to 750 nm) is exhibited by reflected light of 60 to 70 degrees, and thus red can be recognized in oblique observation.

When this thickness is set to 300 nm to 330 nm, the vertical reflected light becomes blue (“blue”: 450 nm to 495 nm), but when the observation angle is increased, the reflected light enters the ultraviolet region, so the color is no longer recognized. Can not do.
Therefore, when the transparent metal thin film formed on the flake surface is an ink in which titanium oxide having a thickness of 100 nm and 300 nm are mixed, and an ink layer is formed using the ink,
It is possible to create a color variable ink that exhibits “blue” as the vertical reflected light and exhibits “red” when observed at 70 degrees, that is, “red shift”.
When the color variable ink layer is formed, if each pigment is evenly distributed, the switching performance becomes clear, so by changing the size of the flakes, small flakes in the gaps of large flakes It is desirable that the particle size is adjusted so that the vertical cross-sectional area (the area of the reflecting portion viewed from the observation side) is substantially the same.
Of course, the color change of “Red Shift” is emphasized by “Blue”, and when the observation angle is increased, the mixture ratio etc. are adjusted according to various variations such as slightly showing “Red”. There is a need to.
In addition, the amount of reflected light from the pigment for “blue” is changed in order to make the change characteristic, such as interpolating the change from “blue” to “red” to make the change smooth. , In addition to adjusting the amount of reflected light from the “red” pigment (adjusting the reflected area, ie, adjusting the sum of the flat areas of the flat pigment), the reflected wavelength range is relatively narrow, It is also preferred to add pigments exhibiting a color between "blue" and "red". For example, “green” is used. In this case, a pigment that causes Bragg reflection is added only at a reflection angle of 30 to 40 degrees. As will be described later, this is obtained by a liquid crystal pigment having a strong selective wavelength. It can also be obtained by making the transparent metal thin film of pearl pigment and effect pigment into a multilayer.
Furthermore, since the intensity of reflected light reflected at a specific reflection angle such as “blue” or “red” can be controlled by the shape and amount of the color variable pigment, only the genuine ink manufacturer knows how to do “blue shift”. High anti-counterfeiting effect can be obtained by making it complicated.
As described above, when the incident angle changes from 0 degree to 70 degrees, the wavelength of the selectively reflected light of the pigment is
A pigment that shifts from the visible region of 500 nm or less to the ultraviolet region and a pigment that shifts from the infrared region to the visible region of 500 nm or more are mixed, and an appropriate resin, solvent, and additive are added to aggregate the pigment. Dispersion treatment for unraveling is performed to obtain the color variable ink of the present invention.
In particular, when two types of pigments are prepared by the same manufacturing method, only the thickness of the transparent oxide thin film is different, and the flakes have the same size, shape, etc. Therefore, the composition and the pigment distribution in the ink layer can be maintained uniformly during the production of the color variable ink composition and further during the formation of the color variable ink layer.

As the liquid crystal pigment, a three-dimensional cross-linking substance having a liquid crystal structure having a chiral phase can be used. As the liquid crystal substance having a chiral phase, various cholesteric liquid crystals can be used, and the liquid crystal substance can be manufactured by adding a chiral substance to a nematic, smectic, or discotic structure.
The three-dimensional crosslinkable resin has a polymerizable group, a polycondensable group, or a group capable of polyaddition, and a part of these groups is preferably a polyfunctional group having two or more functions. For example, a methacryloxy group or an acryloxy group. More preferred three-dimensional crosslinkable resins include polyorganosiloxane.
Both of the above are mixed and then reacted by heating under reflux to isolate the product. The resulting product is further melt-mixed with a photopolymerization initiator to form a coating composition. This coating composition is hot-melt coated on a polyethylene terephthalate resin film, oriented by a doctor, and then irradiated with ultraviolet rays. Is applied to crosslink the coating film, the crosslinked coating film is separated from the film, and finally pulverized into a liquid crystal pigment.
For the purpose of improving the dispersibility in the ink composition, the liquid crystal pigment may have an organic polymer, oligomer, or low molecular dispersant of about 0.01 mg / m 2 or more on the surface of the liquid crystal pigment. Good.
Cholesteric liquid crystals are induced by adding a small amount of an optically active substance (chiral agent) to nematic liquid crystals, and have a spiral structure with a constant period with respect to the reference direction, thereby showing a refractive index change in the liquid crystal layer. Are layered. The multilayer structure having this refractive index distribution has a property of reflecting the incident light for observation after selecting the wavelength at a predetermined angle.
The wavelength of the selectively reflected light is determined by the refractive index (distribution) of the cholesteric liquid crystal and the interval between the refractive index changing layers. This interval is adjusted by the molecular length of the three-dimensional crosslinkable resin, the position of the functional group, the addition amount of the chiral substance, and the like.
Accordingly, the liquid crystal itself has a refractive index distribution, and this refractive index distribution is formed by laminating the above-described thin films in multiple layers (the portion where the twist of the cholesteric liquid crystal goes around is one layer, and this layer is repeatedly present). By producing the same effect as that of the thin film, selective reflectivity is exhibited, and the wavelength of the reflected light “blue shifts” like the thin film.

However, when the number of layers increases, “Bragg reflection” occurs, and only a single wavelength (meaning that the width of the reflected wavelength is narrowed) is reflected at a predetermined angle. Therefore, the thickness of the liquid crystal pigment is set so that the refractive index distribution in the liquid crystal pigment is 3 or more and 20 or less (one layer is 200 nm to 1000 nm), and the incident angle is 0 degree to 70 degrees. It is assumed that it has necessary reflected light. If the number of layers is less than 3, the wavelength selectivity is insufficient, and if it exceeds 20, the width of the reflection wavelength is 50 nm or less, and the reflection angle is limited. Preferably, when the number is 5 layers or more and 10 layers or less, the wavelength selectivity and the width of the reflection angle are desired.
That is, when the incident angle of the light to be observed changes from 0 degree to 70 degrees, the wavelength of the selectively reflected light shifts from the visible region of 500 nm or less to the ultraviolet region. The reflection conditions need to be relaxed, and the situation can be shifted from the infrared region to the visible region of 500 nm or more by the same method. Of course, it is not necessary to emit strong reflected light over the entire range of the predetermined angle, and when the authenticity of the continuity of the color change is determined, it is set so that the continuity can be recognized.
The cholesteric liquid crystal (resined due to curing or the like) is made into flakes, and the selection of the pigment is performed when the incident angle of light to be observed changes from 0 degrees to 70 degrees as in the case of pearl pigments. The pigment that shifts the wavelength of reflected light from the visible region of 500 nm or less to the ultraviolet region and the pigment that shifts from the infrared region to the visible region of 500 nm or more are mixed to obtain a color variable ink composition.
Various resins for ink can be used as the resin for converting the liquid crystal pigment into an ink. In particular, an ionizing radiation curable resin is preferred because of its high curability and physical properties. As the ionizing radiation curable resin, aliphatic acrylates, cycloaliphatic acrylates, and acrylics such as these methacrylates can be used. Furthermore, a vinyl photopolymerizable monomer or oligomer can be used.
In addition, rosin and other natural resins, soybean oil-modified alkyd resins, and other oxidative polymerizable resins, acrylic resins, polyesters, polyvinyl acetate, melamine resins, epoxy resins, phenol resins, etc. Alternatively, a mixture or copolymer of these can be used as appropriate.
As other additives, those similar to the color variable ink composition using a pearl pigment or the like can be used.

When these color variable ink compositions are used to form a color variable ink layer by an appropriate printing method, when the incident angle of light to be observed changes from 0 degrees to 70 degrees, the wavelength of the reflected light is Observed as if "red shift".
A transparent resin layer used for hologram formation is formed on one surface of the color variable ink layer, and a hologram image (including a diffraction grating) is formed on the surface of the transparent resin layer opposite to the color variable ink layer. A hologram forming layer is provided by transferring the hologram relief formed on the hologram master to the transparent resin layer by overlapping the formed master (hologram master) and applying appropriate heating and pressing.
Alternatively, the resin used for forming the hologram may be an ionizing radiation curable resin, and the hologram master may be overlaid and then irradiated with appropriate ionizing radiation to form a hologram relief. At this time, the color variable ink layer is transparent to ionizing radiation irradiated in a direction perpendicular to the color variable ink layer, which is preferable.
Further, a color variable ink layer may be provided on a transparent substrate such as polyethylene terephthalate, and a hologram forming layer may be provided on the opposite side. In this case, the degree of freedom in selecting a resin for forming a hologram is increased, and at the same time, when forming a hologram. The setting range of overheating and pressurizing conditions becomes wider.
When the hologram relief surface of the hologram forming layer is illuminated with light to be observed (referred to as reference light), the reference light is diffracted in a predetermined direction and a hologram image is formed at a predetermined position.
The hologram relief may be provided with a reflective layer, and may be provided with a metal reflective thin film that totally reflects visible light or a transparent reflective thin film that reflects part of visible light and transmits part of it.
The authenticity determination body with a color variable function according to the present invention has the color variable ink layer and the hologram forming layer overlapped. Therefore, the light for observing the authenticity determination body with the color variable function is first determined by the color variable ink layer. Light (selective reflected light) is reflected in the regular reflection direction in that layer, producing a unique color tone, but transmitted light without being reflected (complementary to the selectively reflected light) reaches the hologram forming layer. Thus, the hologram formed by the color tone is imaged in a direction different from the regular reflection direction by being reflected by the hologram relief formed in the hologram forming layer. These specularly reflected light and hologram are observed with a unique color tone depending on the incident angle of light to be observed.
Therefore, the authenticity determination body with a color variable function according to the present invention can visually confirm each of the “red shift” effect and the hologram image exhibiting a unique color tone. False determination can be made.
Furthermore, the color variable ink layer may be formed into a pattern shape as a design or security mark that harmonizes with the design of the security object, or may be formed into a pattern shape in combination with a hologram design. These relations increase the anti-counterfeiting property. Various printing methods can be used as a method for forming the color variable ink layer into a pattern.

When the observation light is incident at 0 degree, the hologram image is a complementary color of “blue”. Therefore, when this image forming direction is directed to the 45 degree direction, it is a portion without “blue” and “red” reflected light, and is clear. The reproduced image can be confirmed. In addition, when this imaging direction is set to 60, the hologram image can be observed while being hidden in the “red” reflected light.
Further, when the hologram image is formed in the direction of 0 °, the hologram image is formed with “blue” complementary color light, so that it is observed in a state close to white light and blocks the “blue” (optical filter. It is also possible to impart a novel anti-counterfeiting property such as being able to observe a hologram image only after observing.
Further, the unexpectedness can be enhanced by making the pigment exhibiting “red” less than the pigment exhibiting “blue” and reducing it to the same amount or even 1/9. That is, at the time of observation in the vertical direction, blue is displayed from the beginning, changing the angle a little, entering the invisible region (ultraviolet region), and when the color disappears, the observation is terminated at that point, and the observation angle is further increased, It is hard to notice that it becomes 60 degrees to 70 degrees, and again exhibits “red” which is another color. When the observation angle is changed after exhibiting “blue”, the invisible region (the ultraviolet region portion and the infrared region portion overlap each other to a certain extent, that is, about 50 to 70 degrees, and the color appears to disappear. It is also preferable to design it so that it suddenly appears “red” when it is further tilted. The anti-counterfeiting property, that is, the stronger the degree of disappearance of the color (the more no color is caused by scattered light and the colorless state continues), the higher the forgery prevention property is.
The second aspect of the present invention is:
The color variable ink layer has a hologram relief on its surface.
According to the second aspect of the present invention,
The authenticity determination body with a color variable function according to claim 1, wherein the color variable ink layer has a hologram relief on a surface thereof.
The hologram master used for forming the hologram relief described above is superimposed on the color variable ink layer itself, and a hologram relief can be formed on the surface of the color variable ink layer by the same method as described above.
The unevenness of the hologram relief is as small as about 0.01 μm, and even if the color variable ink layer is laid with a pigment for the color variable ink, it can be sufficiently formed on the transparent resin that forms the color variable ink layer. . The light that illuminates the hologram relief and the light reflected by the hologram relief and transmitted again through the color variable ink layer (light that forms the hologram) is refracted in a complex manner by pigments for color variable ink. Then, since it does not contribute to the hologram image formation, if the color variable ink pigment scatters light in various directions, the imaged hologram cannot be observed.
Therefore, in the color variable ink layer, the pigment for the color variable ink is spread in parallel with the surface of the color variable ink layer, and the state of transmitting light through a simple path, that is, the wave front of the transmitted light is not complicated. It is desirable to transmit light that remains simple (the wavefront of light to be observed is very monotonically geometric).
The hologram relief may be provided with a reflective layer, and may be provided with a metal reflective thin film that totally reflects visible light or a transparent reflective thin film that reflects part of visible light and transmits part of it. .
From the physical point of view, by forming the hologram relief directly on the color variable ink layer, the overall thickness of the true / false authenticator with color variable function can be reduced, facilitating application to transfer foil, transfer foil, etc. be able to.

According to the authenticity determination body with a color variable function of the present invention,
In a color variable ink layer containing a pigment whose wavelength of selectively reflected light changes according to the incident angle of light to be observed, when the incident angle changes from 0 degrees to 70 degrees, the selectiveness of the pigment is selected. The wavelength of the light reflected by
It changes from “blue” and exhibits “red”. In other words, a new color variable ink layer exhibiting “red shift” is provided, and a hologram image having a unique color tone can be reproduced together. Due to its novelty, it can be applied to various security products. It is possible to prove authenticity.
Further, by adjusting the mixing ratio of the pigments, it is possible to adjust the color change, to bring about an unexpected color change and the like, and to further improve the anti-counterfeiting property.

FIG. 2 is a cross-sectional view of a true / false determination object A with a color variable function showing an embodiment of the present invention, in which light to be observed is incident perpendicularly (reference direction) to the authenticity determination object with a color variable function and reflected light is vertical. FIG. It is sectional drawing of the authenticity determination body A 'with a color variable function which shows another Example of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Color variable ink composition)
The color variable ink composition forming the color variable ink layer 1 of the present invention includes two types of pigments having different optical characteristics. These two types of pigments are pigments that change the wavelength of light that is selectively reflected according to the incident angle of light to be observed, and are dispersed in an appropriate resin, solvent, or the like as a color variable ink composition. By forming it on the surface of a plastic film or the like to form a forgery prevention body, or by forming it directly on the surface of the security object by an appropriate method such as various printing methods, the color variable ink layer 1 is obtained. It is used for authenticity determination by visual observation in various scenes and for authenticity verification.
(Color variable pigment)
The color variable pigment 1a used in the present invention is:
As the incident angle of the light to be observed on the color variable ink layer 1 changes from 0 degree to 70 degrees, it is selectively used as light emitted from each color pigment and finally from the color variable ink layer 1. The wavelength of the light reflected on the surface is composed of a pigment that shifts from the visible region of 500 nm or less to the ultraviolet region, and a pigment that shifts from the infrared region to the visible region of 500 nm or more.
As the pigment, a pearl pigment, an effect pigment, and a liquid crystal pigment are used.
As a pearl pigment,
Merck Iriodin 100 Silver Pearl, 103 Rutile Sterling Silver, 111 Rutile Fine Satin, 120 Raster Satin, 123 Bright Raster, 151 Rutile Pearl, 153 Flash Pearl, 163, Simmer Pearl, 183 Super Nova White, 201 Rutile Fine Gold, 211 rutile fine red, 221 rutile fine blue, 223 rutile fine lilac, 231 rutile fine green, 205 rutile platinum, 215 rutile red pearl, 217 rutile red pearl, 219 rutile lilac pearl, 225 rutile blue pearl, 235 rutile green pearl, 249 Flash Gold, 259 Flash Red, 289 Flash Blue, 299 Flash Green, 300 Gold Ludo Pearl, 302 Gold Satin, 303 Royal Gold, 306 Olympic Gold, 309 Medallion Gold, 320 Bright Gold, 323 Royal Gold, 351 Sunny Gold, 355 Glitter Gold, 500 Bronze, 502 Red Brown, 504 Red, 505 Red Violet, 507 Sheila Bread, 520 bronze satin, 522 red brown, 524 red satin, 530 glitter bronze, 532 glitter red brown, 534 glitter red, etc. are used.

Further, Pearl Glaze MM-100R, MF-100, MF-100RN, ME-100, MS-100R, MY-100RF, MRB-100RF, MV-100RF, MB-100RF, MG-100RF, MC-, manufactured by Sano Paint Co., Ltd. 302, MC-323R, MC-326R, MC-520, MC-522, MC-524, etc.
BASF Corp. DESERT REFLECTIONS CANYON SUNSET, DESERT REFLECTIONSPAINTED DESERT PLUM, TIMICA SILK WHITE, TIMICA NU-ANTIQUE SILVER, FLAMENCO SATIN BLUE, FLAMENCO SATIN PEARL 3500, CLOISONNE RED, CLOISONNE VIOLET, CLOISONNE BLUE, CLOISONNE SATIN BRONZE, SATAIN BLUE, DUOCROME RO , DUOCROME RO, DUOCROME VB, GEMTONE GARNET, GEMTON MAUVE QUARTZ, CELLINI RED, CELLINI BLUE, REFLECKS AYS OF RED, REFLECKS BEAMS OF BLUE, CHROMA-LITE DARK BLUE, CHROMA-LITE MAGENTA, COSMICA BLUE, RED, ORANGE or the like is used.
As an effect pigment,
SILALIC F60-50SW FIRESIDE COPPER, F60-51SW RADIANT RED, T60-10SW CRYSTAL SILVER, T60-20 SW SUNBEAME GOLD, T60-21 SW SOLARIS RED, T60-23 SWGAL ELG T60-22 WNT AMETHYST DREAM, T60-25 SW COSMIC TURQUIOISE, etc.
In addition, Merck Color Stream F20-00WNT AUTAMN MYSTERY, F20-01 WNT VIOLA FANTASY, F20-02 Arctic FIRE, F20-03 TROPIC SUNRISE, F20-03 LAPIS SUNLIGHT IMIVAL 53W
Merck's bi-flare 49, 83, 84, L200, Minatech 230A-IR, Pyrisma T40-20SW YELLOW, T40-21SWRED, T40-22 SW VIOLET, T40-23 BLUE, T40-24 GREEN, T40-25 TURQUIOISE, T40 -27 INDIGO etc.
In addition, Merck's Miraval SCENIC WHITE, SCENIC GOLD, SCENIC COPPER, SCENIC TURQOISE, MAGIC WHITE, MAGIC GOLD, MAGIC COPPER, MAGIC RED, MAGIC LILAC, MAGIC BLUE, MAGIC BLUE, MAGIC BLUE, MAGIC BLUE

(Cholesteric liquid crystal pigment)
The cholesteric liquid crystals used as the basis of cholesteric liquid crystal pigments include cholesterol halides, monocarboxylic acid cholesterol esters, monocarboxylic acid sitosterol esters, benzoic acid derivative cholestanol esters, dibasic acid dicholesteryl esters, Examples thereof include molecular compounds, side chain type liquid crystal polymer compounds, and rigid main chain type liquid crystal polymer compounds.
More specifically, for example, cholesteryl chloride, cholesteryl acetate, cholesteryl nonanoate, methyl carbonate, ethyl cholesterol, cholesteryl p-methoxybenzoate, sitosteroyl benzoate, sitosteroyl p-methyl benzoate, cholestanyl benzoate, 10, 12- Docosadiin dicarboxylic acid dicholesteryl ester, 8,12-eicosadicarboxylic acid dicholesteryl ester, 10,12-pentacosadiin dicarboxylic acid dicholesteryl ester, dodecadicarboxylic acid dicholesteryl ester, 12,14-hexacosadiin dicarboxylic acid Dicholesteryl ester, 4- (7-cholesteryloxycarbonylheptyloxy) phenoxyoctanoic acid cholesteryl ester, L-glu Min acid -γ- benzyl / L-glutamate -γ- dodecyl copolymers and the like.
Further, cholesteryl formate, cholesteryl acetate, cholesteryl propionate, cholesteryl butyrate, cholesteryl pentanate, cholesteryl hexanate, cholesteryl heptanoate, cholesteryl octanate, cholesteryl nonanoate, cholesteryl decanate, cholesteryl decanate (cholesteryl laurate) Cholesteryl myristate, cholesteryl palmitate, cholesteryl stearate, cholesteryl oleate, cholesteryl oleyl carbonate, cholesteryl linoleate, cholesteryl 12-hydroxystearate, cholesteryl mercaptan, cholesterol chloride, cholesteryl fluoride, cholesteryl bromide, cholesteryl iodide, etc. Can be mentioned.
Preferably, a mixture of three kinds of alkyl cholesterol (for example, cholesterol nanoate) and cholesteryl halide (for example, cholesterol chloride) cholesteryl oleyl carbonate is used, and these three types of liquid crystals are used so as to be used at room temperature. Is common.
In addition, it is not limited to the compound shown here, Moreover, these cholesteric liquid crystal compounds can be used 1 type or in mixture of 2 or more types.
As a liquid crystal compound in which a chiral compound is added to a nematic liquid crystal compound, 4-substituted benzoic acid 4′-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4′-substituted phenyl ester, 4-substituted cyclohexane Carboxylic acid 4′-substituted biphenyl ester, 4- (4-substituted cyclohexanecarbonyloxy) benzoic acid 4′-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4′-substituted phenyl ester, 4- (4- Substituted cyclohexyl) benzoic acid 4'-substituted cyclohexyl ester, 4-substituted 4'-substituted biphenyl, 4-substituted phenyl 4'-substituted cyclohexane, 4'-substituted cyclohexane, 2- (4-substituted phenyl) -5-substituted pyridine Etc. are used.

Further, a liquid crystal compound having a cyano group or a fluorine atom at least at one end of the molecule and various suitable chiral agents added to these liquid crystal compounds are used. As the chiral compound, “CB-15”, “C-15” (manufactured by BDH), “CM-21”, “CM-22”, “CM-19”, “CM-20”, “CM” (Above, manufactured by Chisso Corporation), "S1082", "S-811", "R-811" (above, manufactured by Merck & Co., Inc.), and the like.
Furthermore, a three-dimensionally crosslinkable liquid crystalline polymerizable monomer molecule or polymerizable oligomer molecule can be used. A layer containing cholesteric liquid crystal molecules can be obtained by adding an arbitrary chiral agent to a predetermined polymerizable monomer molecule or polymerizable oligomer molecule.
Examples of the three-dimensionally crosslinkable monomer molecule include a mixture of a liquid crystal monomer and a chiral compound as disclosed in, for example, JP-A-7-258638 and JP-T-10-508882. As a more specific example, for example, liquid crystalline monomers represented by the following general chemical formulas (1) to (11) can be used. In the case of the liquid crystalline monomer represented by the general chemical formula (11), X is preferably an integer in the range of 2 to 5.

Moreover, as a chiral agent, a chiral agent as shown, for example by the following general chemical formula (12)-(14) can be used. In the case of the chiral agent represented by the general chemical formulas (12) and (13), X is preferably an integer in the range of 2 to 12, and the general chemical formula (1
In the case of the chiral agent represented by 4), X is preferably an integer in the range of 2-5.

When oligomer molecules are used, a cyclic organopolysiloxane compound having a cholesteric phase as disclosed in, for example, JP-A-57-165480 can be used. For example, a cholesteric liquid crystal layer can be obtained by adding about several to 10% of a chiral agent to polymerizable monomer molecules or polymerizable oligomer molecules.
Further, a cholesteric liquid crystal having no cholesterol group in which a group having an asymmetric carbon is introduced into a terminal group of a nematic liquid crystal obtained by organic synthesis, or a mixed liquid crystal in which a Schiff nematic liquid crystal is added to a cholesterol derivative is also used. Furthermore, halogen substitution products and esterified products of natural cholesterol (cholesteryl benzoate, cholesteryl chloride, cholesteryl oleate, cholesteryl nonanoate, and the like are also suitable.
Particularly preferably, it has a liquid crystal structure having a chiral phase formed by adding a chiral substance to a nematic, smectic, or discotic structure, and has a polymerizable group, a polycondensable group, or a group capable of polyaddition. For example, an oriented three-dimensional cross-linking substance having a bifunctional or higher polyfunctional group such as a methacryloxy group or an acryloxy group can be used. As the three-dimensional crosslinkable resin, polyorganosiloxane is most suitable because of its performance stability and workability.
Both of the above are mixed and reacted by heating under reflux to isolate the product. The resulting product is further melt-mixed with a photopolymerization initiator to form a coating composition. This coating composition is hot-melt coated on a polyethylene terephthalate resin film, oriented by a doctor, and then irradiated with ultraviolet rays. Is applied to crosslink the coating film, the crosslinked coating film is separated from the film, and finally pulverized into a liquid crystal pigment.
In any case, after forming into a film (resin) once, it is made into flakes through a fragmentation process such as crushing and cutting.
For the purpose of improving the dispersibility in the ink composition, those having an organic polymer, oligomer or low molecular dispersant of about 0.01 mg / m 2 or more on the surface of the liquid crystal pigment are also suitable.

(Pearl pigment inks)
Resins used for inks such as pearl pigments include polymethyl methacrylate (refractive index n = 1.49), polymethyl acrylate (n = 1.47), polybenzyl methacrylate (n = 1.57), polybutyl acrylate (N = 1.44), polyisobutyl acrylate (n = 1.48), cellulose nitrate (n = 1.54), methyl cellulose (n = 1.50), cellulose acetate propionate (n = 1.47) ), Polystyrene (n = 1.60), polyethylene terephthalate (n = 1.64), polyvinyl acetate (n = 1.47), polyvinyl chloride / vinyl acetate (n = 1.54), melamine resin (n = 1.56), epoxy resin (n = 1.61), phenol resin (n = 1.60), etc., or a mixture thereof can be used as appropriate. .
The optimum solvent is selected depending on the color variable ink layer forming method.
Solvents include esters: ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, etc., ethers: ethyl ether, etc., ketones: methyl ethyl ketone, isobutyl ketone, methyl isobutyl ketone, glycol ether (Celsolve) ): Ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, etc., alicyclic hydrocarbons: cyclohexanone, methylcyclohexanone, methylcyclohexanol, etc., aliphatic hydrocarbons: Normal hexane, etc., aromatics: toluene, xylene, etc., alcohols: ethanol, isopropyl alcohol, normal butanol, normal amyl alcohol , Isoamyl alcohol, using isobutanol and mixtures thereof.
These are classified into low boiling point solvents (boiling point 100 ° C or lower), medium boiling point solvents (boiling point 100 ° C to 150 ° C), and high boiling point solvents (boiling point 150 ° C or higher) according to the boiling point. Adjust the flakes to be parallel to the surface of the color variable ink layer, such as mixing with boiling point solvents and devising to gradually dry out while suppressing rapid solvent volatilization.
Furthermore, in consideration of transparency, various additives, dispersants, leveling agents, lubricants, plasticizers, coupling agents, antifoaming agents, ultraviolet absorbers, various curing accelerators and the like are used.
The color variable ink forming method is used in various methods such as offset printing, letterpress printing, gravure printing, nozzle printing, curtain coat printing, silk screen printing, intaglio printing, inkjet printing, etc. in order to fully demonstrate the functions of the present invention. The solvent composition, ink viscosity adjustment and drying / curing methods can be devised.
Of course, in consideration of the environment, it is also suitable to use a water-based ink composition using a water-soluble resin such as polyvinyl alcohol.

(Cholesteric liquid crystal pigment ink)
The following acrylic resins can be used as the ionizing radiation curable resin as a resin for converting the liquid crystal pigment into an ink. Namely, acrylic acid, aliphatic acrylate, allyl acrylate, allylated cyclohexyl acrylate, benzyl acrylate, bisphenol A diacrylate, epichlorohydrin modified bisphenol A diacrylate, ethylene oxide modified bisphenol A diacrylate, epichlorohydrin / ethylene oxide modified bisphenol A diacrylate , Ethylene oxide modified bisphenol S diacrylate, ethylene glycol acrylate, propylene glycol acrylate, butylene glycol acrylate, neopentyl glycol acrylate, butoxyethyl acrylate, epichlorohydrin modified aliphatic acrylate, cycloaliphatic acrylate, N, N- Dimethylaminoethyl acrylate, N-diethylaminoethyl acrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified di Pentaerythritol triacrylate, caprolactone modified pentaerythritol hexaacrylate, ethylene oxide modified bisphenol A diacrylate, ditrimethylolpropane tetraacrylate, bisphenol epoxy acrylate, glycerol acrylate, glycidyl acrylate, oligoester acrylate, polyester Acrylate, phosphate type acrylate, ethylene oxide-modified phthalic acid acrylates, ethylene oxide-modified phthalic acid acrylate, epichlorohydrin-modified phthalic acid acrylate or urethane acrylate can be used.
Moreover, the following methacrylic type can also be used, and specifically, the corresponding methacrylic acid and the corresponding methacrylic acid ester listed above as the acrylic type can be used. In addition, as the ionizing radiation curable resin, a vinyl-based photopolymerizable monomer or oligomer such as N-vinylpyrrolidone can be used. As the ionizing radiation curable resin, one type or two or more types of monomers or oligomers of the substances described above can be used.

When an ionizing radiation curable resin is used as a resin and ultraviolet rays are used as ionizing radiation, a known photopolymerization initiator is blended. As the photopolymerization initiator, benzophenone-based, benzyl-based, benzoin-based, benzoic acid-based, thioxanthone-based, phenyl ketone-based, oxime-based organic low-molecular compounds, oligomers, or high-molecular compounds can be used. When the blending ratio is excessive, the degree of polymerization decreases. When the blending ratio is too small, the polymerization rate and the polymerization rate decrease. In any case, the drying characteristics and the film strength after printing. Etc. are preferably used at a mass ratio of 0.3 to 20 parts with respect to 100 parts of ionizing radiation curable resin which is a resin.
The particle size of the liquid crystal pigment is larger than the particle size of the pigment particles used in general lithographic inks and letterpress inks, so if you add too much, the fluidity of the ink may be poor or curability If the amount is too small, the color rendering effect as a pigment is reduced. Therefore, it is preferably used in a mass ratio of 5 to 100 parts with respect to 100 parts of ionizing radiation curable resin as a resin. Is preferred.
The following can be used for the oxidatively polymerizable resin as a resin for converting the liquid crystal pigment into an ink.
That is, natural resins such as rosin, cured rosin, rosin ester, rosin-derived maleic acid resin, or natural resin derivatives such as rosin-derived fumaric acid resin, phenol resin, rosin-modified phenol resin, rosin-modified xylene resin, fatty acid-modified xylene resin, A synthetic resin such as an oil-modified alkyd resin or soybean oil-modified alkyd resin can be used.
For the purpose of adjusting the viscosity and adjusting the drying speed, the above oxidatively polymerizable resin is usually blended with an oil component. Specific oils are obtained by processing vegetable oils such as linseed oil, linden oil, jute oil, hemp seed oil, safflower oil, soybean oil, palm oil, tall oil, castor oil, or cottonseed oil, or vegetable oil. Polymerized oils, processed oils such as maleic acid, or mineral oils such as machine oil or spindle oil can be used.
When using the oxidation polymerizable resin, various solvents or additives can be blended in addition to the oil. As the solvent, aliphatic hydrocarbon-based, aromatic hydrocarbon-based, alcohol-based, glycol-based, ester-based, or ketone-based solvents can be used. In addition, plasticizers (phthalate ester, adipic acid ester, or sebacic acid ester, etc.), wax (carnauba wax, wax, paraffin wax, polyethylene wax, polytetrafluoroethylene, etc.), dryer (cobalt, etc.) Or manganese metal soap), dispersant (polymer or low molecular surfactant, etc.), thickener (aluminum chelate, etc.), antifoaming agent (silicone, etc.), antioxidant (phenolic or An oxime type or the like), a leveling agent (silicone or the like), or an ultraviolet absorber (benzophenone type or triazole type or the like) can be used.

When using an oxidatively polymerizable resin as a resin, the vehicle component mainly composed of an oxidatively polymerizable resin, an oil component, and a solvent component generally has a higher acid value than an ionizing radiation curable resin. Since the compound itself exhibits a dispersant effect, the blending ratio of the liquid crystal pigment can be increased. However, since the liquid crystal pigment has a large particle size, if it is excessively mixed, the fluidity of the ink may be poor or the curability may be lowered. If it is too small, the color rendering effect as a pigment may be reduced. Preferably, it is preferably used in a mass ratio of 5 to 150 parts with respect to 100 parts of the total amount of the oxidatively polymerizable resin as a resin and the oil.
Further, acrylic resin, cellulose resin, polystyrene, polyester, polyvinyl acetate, melamine resin, epoxy resin, phenol resin, etc., or a mixture or copolymer thereof is appropriately used as a resin for forming a liquid crystal pigment into an ink. be able to.
As other additives, those similar to the color variable ink composition using a pearl pigment or the like can be used.
The same solvent as the color variable ink composition using a pearl pigment or the like can be used.
When the color variable ink layer 1 is formed by an appropriate printing method using these color variable ink compositions, the wavelength of the reflected light is changed when the incident angle of the observed light changes from 0 degrees to 70 degrees. It is observed as if it were “red shift”.
Since this “red shift” is designed in advance, the authenticity can be confirmed by a simple but reliable method by visually confirming this change.
Of course, if a change such as a good reflected light is inserted in the change as “red shift” or the reflected light is interrupted in the middle, it is no longer formed from the ink composition of the present invention. Even if the behavior of the reflected light of the color variable ink layer 1 is analyzed in detail, it seems difficult to produce a color variable ink composition that exhibits the same behavior.

(Hologram forming layer)
Various resin materials such as various thermosetting resins, thermoplastic resins, and ionizing radiation curable resins can be selected as the transparent resin material for constituting the hologram forming layer 2. Examples of the thermosetting resin include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, epoxy-modified unsaturated polyester resins, alkyd resins, and phenol resins. Examples of the thermoplastic resin include acrylate resin, acrylamide resin, nitrocellulose resin, and polystyrene resin. These resins can be used alone or as two or more types of copolymers. In addition, these resins may be used alone or in combination of two or more types of isocyanate resins, metal soaps such as cobalt naphthenate and zinc naphthenate, benzoyl peroxide, peroxides such as methyl ethyl ketone peroxide, benzophenone, acetophenone, anthraquinone, naphthoquinone, A heat or ultraviolet curing agent such as azobisisobutyronitrile or diphenyl sulfide may be blended. Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, and acrylic-modified polyester. Other monofunctional or polyfunctional monomers, oligomers and the like can be conjugated to such ionizing radiation curable resins for the purpose of adjusting the cross-linking structure and viscosity.
The hologram forming layer 2 can be directly formed by developing a photo-sensitive resin material by performing interference exposure of the hologram. However, it is possible to reproduce a relief hologram prepared in advance or a duplicate thereof, or a plating mold thereof. Molding can also be performed by using it as a mold and pressing the mold surface against the resin material. When a thermosetting resin or ionizing radiation curable resin is used, it is cured by heating or irradiation with ionizing radiation while the uncured resin is kept in close contact with the mold surface, and the cured transparent film is peeled off after curing. The fine irregularities of the relief hologram can be formed on one side of the layer made of the resin material. In the present invention, a diffraction grating forming layer having a diffraction grating formed in a pattern by a similar method is also included in the hologram forming layer. Further, a combination of the hologram forming layer 2 and the diffraction grating forming layer is also included.

The ionizing radiation curable resin is preferably (1) an isocyanate having three or more isocyanate groups in the molecule, and (2) at least one hydroxyl group and at least two (meth) acryloyloxy groups in the molecule. Preferably using an ionizing radiation curable resin containing a polyfunctional (meth) acrylate having, or (3) a urethane (meth) acrylate oligomer which is a reaction product of a polyhydric alcohol having at least two hydroxyl groups in the molecule. May contain polyethylene wax, applied, dried, and cured with ionizing radiation to form an ionizing radiation curable resin.
The ionizing radiation curable resin containing the urethane (meth) acrylate oligomer is disclosed in a cured product of an ionizing radiation curable resin containing a urethane (meth) acrylate oligomer, specifically, JP-A-2001-329031. The photocurable resin etc. which can be illustrated. Specifically, MHX405 varnish (product name of ionizing radiation curable resin, manufactured by The Inktec Co., Ltd.) can be exemplified.
(Formation of hologram forming layer)
The hologram-forming layer 2 is formed by using the above-mentioned ionizing radiation curable resin as a main component, adding a photopolymerization initiator, a plasticizer, a stabilizer, a surfactant, and the like, and dispersing or dissolving it in a solvent. 1 may be applied by a coating method such as roll coating, gravure coating, comma coating, die coating, and the like, dried and reacted (cured) with ionizing radiation after shaping a hologram (relief). The thickness of the hologram forming layer 2 is usually about 1 to 10 μm, preferably 2 to 5 μm.
(hologram)
Next, on the surface of the hologram forming layer 2, predetermined fine unevenness (relief structure) such as a hologram that exhibits a light diffraction effect is formed and cured. A hologram is a recording of interference fringes due to the interference of light between object light and reference light in an uneven relief shape. For example, a laser reproduction hologram such as a Fresnel hologram, a white light reproduction hologram such as a rainbow hologram, There are color holograms utilizing the above principle, computer generated holograms (CGH), holographic diffraction gratings and the like.

The method of forming the hologram relief 2b on the surface of the hologram forming layer 2 can be formed by various methods. For example, when recording a diffraction grating or interference fringe of a hologram as a relief of surface irregularities, the diffraction grating or interference fringe An original plate recorded in the form of irregularities is used as a press die, and the original plate is overlaid on the resin layer, and the both are heated and pressure-bonded by an appropriate means such as a heating roll, whereby an uneven pattern of the original plate (hologram relief shape). Can be duplicated.
Using this method, a similar relief shape can be formed directly on the color variable ink layer 1. In this case, the hologram forming layer 2 is not necessary.
Moreover, the hologram pattern formed in the hologram formation layer 2 may be single, or plural. The hologram forming layer 2 is irradiated with ionizing radiation during or after embossing with a stamper to cure the ionizing radiation curable resin. The ionizing radiation curable resin becomes an ionizing radiation curable resin (fine irregularities = relief structure = hologram) when it is cured (reacted) by irradiation with ionizing radiation such as ultraviolet rays or electron beams after the relief is formed. Since this method can be shaped at a relatively low temperature and low pressure, damage to the color variable ink layer 1 can be reduced.
Further, the hologram relief 2 b or the hologram forming layer 2 may be provided on the observation side with respect to the color variable ink layer 1.
The hologram forming layer 2 may be provided with a reflective layer. A reflective thin film layer is formed so as to follow the hologram relief 2 b surface of the hologram forming layer 2. Since this thin film layer needs to reflect incident light, it is not particularly limited as long as it is a thin film layer having a refractive index higher than that of the hologram forming layer 2.
The reflective thin film layer may be a metallic glossy reflective layer that reflects visible light over almost the entire wavelength range, such as a metal thin film formed by vacuum deposition, sputtering, ion plating, etc., or light of a specific wavelength. Any of the transparent reflective layers that appear transparent depending on the viewing direction, etc. can be used because only the reflective direction is reflected. However, when a metallic glossy reflective layer is partially provided or a transparent reflective layer is provided, the transparent reflective layer is passed through. This is preferable because the design of the security object can be confirmed.
Examples of the metal material for forming the reflective thin film layer include Al, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Mg, Sb, Pb, Cd, Bi, Sn, Se, In, A metal such as Ga or Rb, or an oxide or nitride of the metal can be used, and one or more of these can be used in combination. Among these, Al, Cr, Ni, Ag, Au, or the like is particularly preferable, and the film thickness is preferably 1 nm to 10,000 nm, more preferably 2 nm to 200 nm.
The reflective thin film layer may be patterned (partially formed). For example, after forming a reflective thin film layer on the whole surface, the method of removing an unnecessary part can also be used.
The pattern shape of the reflective thin film layer is preferably harmonized with or related to the pattern of the color variable ink layer, the hologram design, and the design of the security object, but it may be a simple pattern and the width in the horizontal direction is narrow and the vertical direction In other words, the reflection layer in which long rectangles are arranged at equal intervals may be a striped pattern formed by arranging the reflection layers at equal intervals, for example, with an interval equal to the length (ie, width) of the rectangle in the left-right direction. Alternatively, it may be a geometric shape (such as a rectangle and a star). Moreover, when a specific pattern as described above is used as a positive pattern, the pattern may be a negative pattern thereof. Note that these patterns are examples, and the patterns may be characters or symbols other than geometric shapes.

The size of the pattern may be small as long as it can be resolved with the naked eye. For example, if the shape is a quadrangle, the length and width can be 1 mm × 1 mm or more, preferably 3 mm × 3 mm or more. Preferably it is 5 mm x 5 mm or more. In the case of a geometric shape, if it is circular, the diameter can be 1 mm or more, preferably 3 mm or more, more preferably 5 mm or more, and in the case of other shapes, an inscribed circle The diameter can be, for example, 1 mm or more, preferably 3 mm or more, more preferably 5 mm or more.
You may align the automatic recognition information on a to-be-transferred object to the vacant part of these patterns.
Conversely, the reflective pattern layer may be laminated in a fine pattern. The pattern (fine pattern) in this case is a fine pattern in the form of a line pattern in which reflective layers made of finite width stripes are arranged from the lower left side to the upper right side at a pitch about twice the width in the width direction. It may be configured, or may be one in which reflective layers having a circular shape or a quadrangular shape are arranged at an equal pitch. In this way, even if the pattern reflection layer is a metal thin film, the pattern reflection layer has transparency and the design under the pattern reflection layer can be visually observed.
These fine patterns are merely examples, and the patterns constituting the fine patterns can be freely determined. Therefore, geometric patterns other than line patterns and halftone dots, and shapes such as letters or symbols are used. There may be. The size of the pattern constituting the fine pattern is preferably a fine one that is difficult to observe or cannot be observed by normal observation. In the case of a line pattern, the line width is set to 0.3 mm, for example. Hereinafter, it can be preferably 0.1 mm or less. The pattern can be made small as long as it can be formed, but is preferably about 0.01 mm or more in practice. When the halftone dot is circular, the diameter can be, for example, 0.3 mm or less, preferably 0.1 mm or less, and preferably about 0.01 mm or more. In addition, when the halftone dots are rectangular, the length and width can be set to, for example, 0.3 mm × 0.3 mm or less, preferably 0.1 mm × 0.1 mm or less, and about 0.01 mm × 0.01 mm or more. It is preferable that In the case of other shapes, the diameter of the inscribed circle can be, for example, 0.3 mm or less, preferably 0.1 mm or less, and preferably about 0.01 mm or more. It is also preferable to include information such as a two-dimensional barcode in this fine pattern.
When the pattern of the reflective thin film layer is a fine pattern, the area ratio of the reflective thin film layer is, for example, 20% to 80%, preferably 30% to 60%.

Moreover, in order to improve reflectivity, you may add a transparent reflective layer. The transparent reflecting layer is provided on the surface of the hologram relief 2b of the hologram forming layer 2 so as to enhance the reflection and / or diffraction effect of the relief. Therefore, if the reflectance is higher or lower than the hologram forming layer 2, It is not limited. The transparent reflective layer is a transparent reflective layer formed by a vacuum thin film method or the like.
The transparent reflective layer has a substantially colorless and transparent hue, and its optical refractive index is different from that of the hologram forming layer 2, so that the brightness of a hologram or the like can be visually recognized even though there is no metallic luster. For example, there are a thin film having a higher light refractive index than that of the hologram forming layer 2 and a thin film having a lower light refractive index. Examples of the former include ZnS, TiO ₂ , Al ₂ O ₃ , Sb ₂ S ₃ , SiO, SnO. ₂ and ITO. Examples of the latter include LiF, MgF ₂ and AlF ₃ . Preferably, it is a metal oxide or nitride, specifically, Be, Mg, Ca, Cr, Mn, Cu, Ag, Al, Sn, In, Te, Fe, Co, Zn, Ge, Pb, Cd , Bi, Se, Ga, Rb, Sb, Pb, Ni, Sr, Ba, La, Ce, Au, and other oxides or nitrides, and the like can be exemplified by a mixture of two or more thereof. The transparent metal compound is formed by vapor deposition, sputtering, ion plating, CVD, etc. on the relief surface of the hologram forming layer 2 so as to have a thickness of about 10 to 2000 nm, preferably 20 to 1000 nm, like the metal thin film. It may be provided by a vacuum thin film method or the like.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this. In addition, except a solvent, each composition of each layer is a mass part of solid content conversion.
Example 1
A color variable ink composition was prepared using a pearl pigment as the color variable pigment 1a.
As the color variable pigment 1a, Iriodin type pigment B (manufactured by Merck & Co., Inc.) (manufactured with natural mica flakes coated with 100 nm titanium oxide, particle size 5 to 25 μm, thickness 2 to 5 μm: 0 degree reflection 1500 nm, 70 degree reflection 700 nm) and Iriodin type pigment C (titanium oxide 300 nm coated on natural mica flakes, particle size 5 to 25 μm, thickness 2 to 5 μm: 0 degree reflection 450 nm, 70 degree reflection 200 nm) was mixed in the same amount to obtain the following ink composition. . In order to prevent the pigment from agglomerating and to uniformly disperse, it was treated with a ball mill containing 2 mm diameter glass beads for 30 minutes to obtain a color variable ink composition.
<Ink composition>
Pigment B 10 parts by mass Pigment C 10 parts by mass Urethane acrylate (refractive index n = 1.49) 30 parts by mass Ethyl acetate 20 parts by mass Isobutyl acetate 10 parts by mass Methyl isobutyl ketone 10 parts by mass Benzophenone photoinitiator 0.1 parts by mass Part This color variable ink composition is coated on a 25 μm thick PET film with a blade coating (coating while applying the blade share) to a thickness of 5 μm after drying, and cured by irradiating with ultraviolet rays, and the color variable ink layer 1 was obtained.
On this color variable ink layer 1, an electron beam curable resin composition having high physical properties is applied, and an electron beam is irradiated while keeping a hologram duplication mold surface in contact with a star mark as a reproduced image. The hologram forming layer 2 and the hologram relief 2b having a thickness of 5 μm were formed by curing the transparent electron beam curable resin composition. On the hologram relief 2b, a reflective aluminum thin film of 100 nm is provided by a vacuum deposition method, and a resist ink for etching (manufactured by Showa Ink Industries Co., Ltd.) is applied thereon by 3 μm by a knife coating method, and pattern exposure and development are performed. Resist ink was left only for the 15 mm size star mark and 5 bar portions of 5 mm height and 100 μm width.
This was etched using a 1% NaOH aqueous solution to remove the unnecessary aluminum thin film to obtain a desired reflective pattern layer, and a true / false judgment body A with a color variable function was obtained.
When the light 3 to be observed on the authenticity determination body A with the color variable function is in the direction perpendicular to the ink layer surface and the reflected light 4 is observed in almost the same direction, the purple to blue color can be observed, and A slightly yellowish star-shaped hologram could be observed at a slightly shifted angle.
Further, when the light 3 to be observed is incident at an angle of 70 degrees from the direction perpendicular to the ink layer surface and the reflected light 4 that appears in the opposite direction at the same angle is observed, red can be observed. As a result, so-called “red shift” and “hologram reproduction image” were confirmed.
When this color variable ink layer formed product was applied as a small piece of 20 mm × 20 mm and applied on a credit card as a security object, the appearance by the observation angle was not the usual “blue shift”, Since it was seen as so-called “red shift” and “hologram reproduction image”, its authenticity could be confirmed very easily by visual observation.

(Example 2)
A hologram relief mold is formed on the surface of the color variable ink layer at 150 ° C. and a pressure of 5 kg / cm 2 by directly contacting the color variable ink layer 1 with a hologram duplication mold surface having a star mark as a reproduced image. Example 2 was obtained in the same manner as Example 1 except for the above (no hologram forming layer).
The effect was the same as that of Example 1, but the total thickness was 5 μm, and it was considered that the transfer foil and the like were workable.
(Example 3)
Example 3 was obtained in the same manner as in Example 1 except that the hologram forming layer 2 was formed on the opposite side of the color variable ink layer 1 of the 25 μm PET film.
The effect was the same as in Example 1, but the hologram relief could be formed more accurately.
Example 4
An effect pigment is used as the color variable pigment 1a, and silylac type pigment B (coating titanium oxide 40-60 nm on alumina flakes, particle size 15-30 μm, thickness 3-5 μm) and Sirillac type pigment C (alumina flakes) The same amount of titanium oxide 140 to 160 nm coating, particle size 5 to 10 μm, thickness 1 to 3 μm) is mixed, the color variable ink layer thickness is 10 μm, and the reflective thin film layer is 10 nm thick using titanium dioxide. Example 4 was obtained in the same manner as Example 1 except that the transparent thin film layer was used.
Although the effect was the same as that of Example 1, in the observation after pasting on the security object, red was clearly observed from Example 1, and the design under the transparent thin film layer could be confirmed.
(Example 5)
As the color variable pigment 1a, a color variable ink composition using the following liquid crystal pigment was used.
<Color variable pigment B>
Heckeron HC sapphire XS 20 parts by weight Wacker Germany Helicone HC Maple XS 20 parts by weight Polyester acrylate 20 parts by weight Ethyl acetate 30 parts by weight Isobuty acetate 10 parts by weight Benzophenone photoinitiator 0.1 parts by weight Example 5 was obtained in the same manner as Example 1 except for the above.
In the same observation as in Example 1, so-called “red shift” and “hologram reproduction image” could be confirmed, and authenticity could be easily confirmed.

(Comparative Example 1)
Comparative Example 1 was obtained in the same manner as Example 1, except that Mercury Pearl Pigment Color Stream Standard Model F10-01 Viola Fantasy was used as the pearl pigment.
When observed in the same manner as in Example 1, “blue shift” generally observed from red to green and blue was confirmed.
This change was common and seemed insufficient to verify authenticity.
(Evaluation test) The observation light is an ordinary white light source, and the observation object is visually observed from the vertical direction as shown in FIG. Observation. Further, as shown in FIG. 2, the light reflected from the direction inclined by 70 degrees from the vertical direction was visually observed.
(Evaluation results)
In Examples 1 to 5, so-called “red shift” and “hologram reproduction image” could be observed. From this, it was judged that sufficient authenticity could be confirmed.
As described above, Comparative Example 1 confirmed the “blue shift” generally observed. This color change seemed insufficient to verify authenticity.

A: True / false determination body with color variable function showing one embodiment of the present invention A ′: True / false determination body with color variable function showing another embodiment of the present invention 1: Color variable ink layer 1a: Selectively reflecting Pigments that change the wavelength of light (pearl pigments, liquid crystal pigments, etc.)
2: Hologram forming layer 2b: Hologram relief 3: Light to be observed 4: Reflected light

Claims (2)

According to the incident angle of the light to be observed, it is a true / false determination body with a color variable function comprising a color variable ink layer containing a pigment whose wavelength of light to be selectively reflected and a hologram forming layer,
When the incident angle changes from 0 degree to 70 degrees, the wavelength of the selectively reflected light of the pigment shifts from a visible region of 500 nm or less to an ultraviolet region, and from the infrared region to 500 nm or more A true / false determination object with a color variable function characterized by including a pigment that shifts to the visible region of The authenticity determination body with a color variable function according to claim 1, wherein the color variable ink layer has a hologram relief on a surface thereof.

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