WO2020153349A1

WO2020153349A1 - Anti-forgery medium and information card

Info

Publication number: WO2020153349A1
Application number: PCT/JP2020/001922
Authority: WO
Inventors: 峻也加藤
Original assignee: 富士フイルム株式会社
Priority date: 2019-01-21
Filing date: 2020-01-21
Publication date: 2020-07-30

Abstract

Provided are an anti-forgery medium and an information card, which enable proper reading, regardless of the position of a sensor, when the anti-forgery medium is irradiated with light for determination of authenticity. This medium has a reflective layer and a support body for supporting the reflective layer, wherein the reflective layer has a cholesteric liquid crystal structure, and the support body has a haze value of at least 2% and a visible light transmission of at least 30%.

Description

Anti-counterfeit media and information cards

The present invention relates to an anti-counterfeit medium and an information card having this anti-counterfeit medium.

Conventionally, as an anti-counterfeit medium used for bills and the like, a medium provided with an embossed hologram on a reflective material such as aluminum has been used. However, the forgery prevention medium using a hologram is becoming easier to forge, and there is a demand for a forgery prevention medium that is more difficult to forge, that is, has high security.

It has been proposed to use a cholesteric liquid crystal layer as a forgery prevention medium with high security.
For example, in Patent Document 1, a transparent substrate, a transfer material including a first cholesteric liquid crystal layer on one surface of the transparent substrate, a patterned second cholesteric liquid crystal layer, and an adhesive layer, and a support substrate A patch transfer medium comprising a support material provided with a peelable resin layer, a transfer portion of a transfer material being half-cut into a patch, and the patch being releasably laminated on the peelable resin layer surface of the support material is described. ing. This patch transfer medium is used by transferring it to an object having a forgery prevention function.

Patent Document 2 includes a base material, an adhesive layer formed on the base material, and a liquid crystal film formed on the adhesive layer, and a surface of the liquid crystal film opposite to the adhesive layer is provided. , A concave-convex structure having a diffractive function is formed, a resin layer covering the concave-convex structure is formed on the liquid crystal film, and the resin layer is formed by curing an active energy ray-curable resin composition. An optical laminate having a glass transition temperature T2 (°C) of 30°C or higher is described. Further, Patent Document 2 describes that this optical laminate can be used as a display medium for preventing forgery.

JP, 2010-120230, A JP, 2005-105962, A

As one of the methods for determining the authenticity of the anti-counterfeit medium, there is a method of irradiating the anti-counterfeit medium with light in a specific wavelength range and reading the light reflected from the anti-counterfeit medium by a sensor. In such a determination method, it is possible to determine the authenticity that is difficult (cannot be determined) by visual observation, so that the security is further improved.

Here, when irradiating the anti-counterfeit medium with light and reading the reflected light, if the positional relationship between the light source and the sensor is arranged at the position of specular reflection, the outermost surface of the anti-counterfeit medium (for example, the surface of the base material, the overcoat) If there is a layer, the light that is specularly reflected by the surface of the overcoat layer, etc. will enter the sensor, and the proportion of the reflected light from the layer used for judging the authenticity of the cholesteric liquid crystal layer will decrease, so it will be read accurately. Can not. Therefore, when irradiating the anti-counterfeit medium with light and reading the reflected light, it is necessary to prevent the positional relationship between the light source and the sensor from being the specular reflection position.
However, the reflection of light by the cholesteric liquid crystal layer is specular reflection. Therefore, for the anti-counterfeit medium having a cholesteric liquid crystal layer, when performing the determination method described above, if the positional relationship between the light source that emits light and the sensor that reads the reflected light is not at the position of specular reflection. However, the amount of light reflected by the cholesteric liquid crystal layer and reaching the sensor is reduced, so that there is a problem that the sensor cannot read.

In view of the above situation, the present invention aims to provide an anti-counterfeit medium and an information card that can be appropriately read regardless of the position of the sensor when irradiating light to the anti-counterfeit medium to determine authenticity. And

In order to solve this problem, the present invention has the following configurations.

[1] A reflective layer and a support that supports the reflective layer,
The reflective layer has a cholesteric liquid crystal structure,
An anti-counterfeit medium in which the haze value of the support is 2% or more and the visible light transmittance is 30% or more.
[2] The anti-counterfeit medium according to [1], wherein the reflective layer has two or more reflective regions having different selective reflection wavelengths of 30 nm or more due to the cholesteric liquid crystal structure.
[3] The anti-counterfeit medium according to [2], wherein the selective reflection wavelength of at least one reflection region is a wavelength in the visible light region.
[4] The forgery prevention medium according to [2] or [3], wherein the selective reflection wavelength of at least one reflection region is a wavelength of the invisible light region.
[5] The anti-counterfeit medium according to [4], wherein the selective reflection wavelength of at least one reflection region is 700 nm or more.
[6] The anti-counterfeit medium according to any one of [2] to [5], which has two or more reflective regions arranged at different positions in the plane.
[7] The anti-counterfeit medium according to any one of [1] to [6], which has a circularly polarizing plate that absorbs circularly polarized light having the same sense as the circularly polarized light reflected by the cholesteric liquid crystal structure of the reflective layer.
[8] The anti-counterfeit medium according to any one of [1] to [7], in which the support has a base material and an intermediate layer.
[9] The anti-counterfeit medium according to [8], wherein the intermediate layer contains fine particles having a particle size of 50 nm or more.
[10] The anti-counterfeit medium according to [8] or [9], wherein the base material is a polyolefin-based polymer material.
[11] The anti-counterfeit medium according to any one of [8] to [10], wherein the front surface retardation of the substrate is 400 nm or less.
[12] The anti-counterfeit medium according to any one of [1] to [11], which has an overcoat layer on the side opposite to the support side of the reflective layer.
[13] An anti-counterfeit medium according to any one of [1] to [12],
An information card having an image printing section.
[14] The information card according to [13], wherein the anti-counterfeit medium and the image printing section are covered with the same overcoat layer.

According to the present invention, it is possible to provide an anti-counterfeit medium and an information card that can be appropriately read regardless of the position of the sensor when irradiating light on the anti-counterfeit medium to determine authenticity.

It is sectional drawing which shows an example of the forgery prevention medium of this invention typically. FIG. 3 is a cross-sectional view for explaining the action of the anti-counterfeit medium shown in FIG. 1. It is sectional drawing for demonstrating the conventional anti-counterfeit medium. It is sectional drawing which shows another example of the forgery prevention medium of this invention typically. It is sectional drawing which shows another example of the forgery prevention medium of this invention typically. It is a schematic diagram for demonstrating the effect|action of the forgery prevention medium shown in FIG. It is a schematic diagram for demonstrating the effect|action of the forgery prevention medium shown in FIG. It is sectional drawing which shows another example of the forgery prevention medium of this invention typically. It is sectional drawing which shows another example of the forgery prevention medium of this invention typically. It is sectional drawing which shows another example of the forgery prevention medium of this invention typically. It is sectional drawing which shows an example of the information card of this invention typically.

Hereinafter, the anti-counterfeit medium of the present invention will be described in detail. In the present specification, the numerical range represented by “to” means the range including the numerical values before and after “to” as the lower limit value and the upper limit value.
In addition, in the present specification, “orthogonal” and “parallel” include a range of error allowed in the technical field to which the present invention belongs. For example, “orthogonal” and “parallel” mean that the angle is within ±10° with respect to the strict orthogonal or parallel, and the error with respect to the strict orthogonal or parallel is 5° or less. Is preferable, and more preferably 3° or less.
In addition, angles represented by other than “orthogonal” and “parallel”, for example, specific angles such as 15° and 45°, also include the error range allowable in the technical field to which the present invention belongs. For example, in the present invention, the angle means that it is less than ±5° with respect to the specifically indicated exact angle, and the error with respect to the indicated exact angle is ±3° or less. Preferably, it is preferably ±1° or less.

In the present specification, “(meth)acrylate” is used to mean “either one or both of acrylate and methacrylate”.
In the present specification, “identical” includes an error range generally accepted in the technical field. Further, in the present specification, when referring to “all”, “any” or “whole surface” and the like, in addition to the case of 100%, the error range generally accepted in the technical field is included, for example, 99% or more, The case where it is 95% or more, or 90% or more is included.

The term “selective” for circularly polarized light means that the light amount of either the right circularly polarized light component or the left circularly polarized light component of light is larger than that of the other circularly polarized light component. Specifically, the term “selective” means that the circular polarization degree of light is preferably 0.3 or more, more preferably 0.6 or more, and further preferably 0.8 or more. More preferably, it is substantially 1.0. Table In _{_{/ (I R + I L)}} | Here, the degree of circular polarization, the intensity of the right circularly polarized light component of the light I _R, when the strength of the left-handed circularly polarized light component and I _{_L,} | I _R -I _L Is the value to be set.

When referring to circularly polarized light as “sense,” it means right-handed circularly polarized light or left-handed circularly polarized light. The sense of circularly polarized light is right circularly polarized when the tip of the electric field vector rotates clockwise with increasing time when viewed as if the light is traveling toward you, and left when it rotates counterclockwise. It is defined as being circularly polarized.

-The term "sense" may be used for the twist direction of the spiral of cholesteric liquid crystal. When the twist direction (sense) of the spiral of the cholesteric liquid crystal is right, right circularly polarized light is reflected and left circularly polarized light is transmitted, and when the sense is left, left circularly polarized light is reflected and right circularly polarized light is transmitted.

Visible light is a part of electromagnetic waves having a wavelength that can be seen by human eyes, and usually shows light in a wavelength range of 380 to 780 nm. The non-visible light is light in a wavelength range of less than 380 nm or a wavelength range of more than 780 nm.
In addition, although not limited thereto, in the visible light, light in the wavelength range of 420 to 490 nm is blue (B) light, and light in the wavelength range of 495 to 570 nm is green (G) light. , Light in the wavelength range of 620 to 750 nm is red (R) light.
Among infrared light, near infrared light is an electromagnetic wave in the wavelength range of 780 nm to 2500 nm. Ultraviolet light is light in the wavelength range of 10 to 380 nm.

The “visible light transmittance” is the visible light transmittance of the A light source defined in JIS (Japanese Industrial Standard) R 3212:2015 (Test method for automobile safety glass). That is, the transmittance of each wavelength in the wavelength range of 380 to 780 nm is measured with a spectrophotometer using the A light source, and is obtained from the wavelength distribution and the wavelength interval of the CIE (International Commission on Illumination) light adaptation standard ratio visual sensitivity. It is the transmittance obtained by multiplying the transmittance at each wavelength by the obtained weighting coefficient and performing a weighted average.
The term "reflected light" or "transmitted light" is used to include scattered light and diffracted light.

The polarization state of each wavelength of light can be measured using a spectral radiance meter or a spectrum meter equipped with a circularly polarizing plate. In this case, the light intensity measured through the right circularly polarizing plate corresponds to I _R , and the light intensity measured through the left circularly polarizing plate corresponds to I _L. It is also possible to measure by attaching a circularly polarizing plate to an illuminometer or an optical spectrum meter. The ratio can be measured by attaching a right circularly polarized light transmitting plate and measuring the right circularly polarized light amount, and by attaching a left circularly polarized light transmitting plate and measuring the left circularly polarized light amount.

The front phase difference is a value measured using an AxoScan manufactured by Axometrics. The measurement wavelength is 550 nm unless otherwise specified. For the front phase difference, a value measured by KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.) with light having a wavelength within the visible light wavelength range incident in the film normal direction can be used. In selecting the measurement wavelength, the wavelength selection filter can be replaced manually or the measurement value can be converted by a program or the like for measurement.

In the present specification, “haze” means a value measured using a haze meter NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
Theoretically, haze means the value represented by the following formula.
(Scattered transmittance of natural light of 380 to 780 nm)/(scattered transmittance of natural light of 380 to 780 nm + direct transmittance of natural light) x 100%
The scattered transmittance is a value that can be calculated by subtracting the direct transmittance from the obtained omnidirectional transmittance using a spectrophotometer and an integrating sphere unit. Direct transmittance is the transmittance at 0° when based on the values measured using an integrating sphere unit. That is, the low haze means that the directly transmitted light amount is large in the total transmitted light amount.
The refractive index is a refractive index for light having a wavelength of 589.3 nm.

<Counterfeit prevention medium>
The anti-counterfeit medium of the present invention is
It has a reflective layer and a support that supports the reflective layer,
The reflective layer has a cholesteric liquid crystal structure,
The anti-counterfeit medium has a haze value of 2% or more and a visible light transmittance of 30% or more.

An example of a preferred embodiment of the forgery prevention medium of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic sectional view of an example of the anti-counterfeit medium of the present invention.
It should be noted that the drawings in the present invention are schematic diagrams, and the relationship of the thickness of each layer, the positional relationship, and the like do not necessarily match the actual ones. The following figures are also the same.
As shown in FIG. 1, the anti-counterfeit medium 10a has a support 12 and a reflective layer 14 in this order.

The reflective layer 14 is a layer having a cholesteric liquid crystal structure. The cholesteric liquid crystal structure reflects wavelength light according to the spiral pitch of the cholesteric liquid crystal structure and wavelength selective reflectivity that transmits light of other wavelength range, and circular polarization of one sense, and the other sense. Circularly polarized light that transmits circularly polarized light is selectively reflected. The reflective layer 14 has a cholesteric structure and reflects circularly polarized light of one sense having a selective reflection wavelength and transmits light of another wavelength and circularly polarized light of the other sense.

The anti-counterfeit medium of the present invention can judge authenticity by utilizing the wavelength-selective reflectivity and the circularly polarized light reflectivity of the cholesteric liquid crystal structure of the reflective layer.
The authenticity of the anti-counterfeit medium is determined by using a light source that emits light having a predetermined center wavelength (and a predetermined sense) and a reader that has a sensor that reads the light reflected by the anti-counterfeit medium. .. For example, when the anti-counterfeit medium is true, the light having a predetermined center wavelength emitted from the light source is reflected by the anti-counterfeit medium (reflection layer), and the sensor can read the light. On the other hand, when the anti-counterfeit medium is false, the light emitted from the light source and having the predetermined center wavelength is not reflected by the anti-counterfeit medium (reflection layer), so that the sensor cannot read the light. This makes it possible to judge the authenticity. Further, by making the light incident on the anti-counterfeit medium into circularly polarized light of one sense, the authenticity can be determined by whether or not the circularly polarized light of this sense can be reflected. That is, the authenticity can be determined by whether or not circularly polarized light with a predetermined sense can be reflected at a predetermined center wavelength. In addition, the authenticity can be determined by whether or not it can be read (visible) through the circularly polarizing plate. Alternatively, it is possible to perform reading through the right circularly polarizing plate and reading through the left circularly polarizing plate, and determine the authenticity according to the intensity difference of the read light.

As a light source used when determining the authenticity of the anti-counterfeit medium, various laser light sources capable of irradiating a narrow band light having a desired center wavelength, LEDs (light emitting diodes), fluorescent lamps and the like can be used.
Further, as the sensor used when determining the authenticity of the anti-counterfeit medium, a known solid-state image sensor such as CCD (Charge Coupled Device) or CMOS (Complementary metal-oxide semiconductor) can be used.

The selective reflection wavelength of the reflective layer 14 (cholesteric liquid crystal structure) is not limited and may be a wavelength in the visible light region, or a wavelength in the invisible light region such as a wavelength in the ultraviolet region or a wavelength in the infrared region. May be.
Here, as the anti-counterfeiting technology, there are an overt technology that enables visual verification or a simple tool to verify authenticity, and a covert technology that requires the use of a dedicated tool for authenticity verification.
By setting the selective reflection wavelength of the reflective layer 14 to a wavelength in the visible light region, it is possible to visually determine the authenticity, and thus an overt anti-counterfeit medium can be obtained. On the other hand, when the selective reflection wavelength of the reflective layer 14 is set to a wavelength in the invisible light region or a wavelength in the visible light region which is difficult to be visually recognized, it becomes invisible to the naked eye, and thus a covert anti-counterfeit medium can be obtained.
From the viewpoint of security (anti-counterfeit property), it is preferable to use a covert anti-counterfeit medium.

The support 12 supports the reflective layer 14. In the example shown in FIG. 1, the support 12 has a base material 16 and an intermediate layer 18.

Here, in the present invention, the support 12 has a haze value of 2% or more and a visible light transmittance of 30% or more.
In the anti-counterfeit medium of the present invention, by setting the haze value and the visible light transmittance of the support 12 in the above ranges, light incident from the support 12 side is diffused and made incident on the reflection layer 14, and the reflection layer. By diffusing the light reflected by 14, the light incident on the anti-counterfeit medium is reflected in various directions other than the direction of specular reflection. Thereby, when the authenticity is determined by irradiating the anti-counterfeit medium with light, it is possible to properly read the information regardless of the position of the sensor.
This point will be described with reference to FIGS. 2 and 3.

FIG. 2 is a diagram for explaining the operation when determining the authenticity of the anti-counterfeit medium 10a of the present invention.
The authenticity of the anti-counterfeit medium 10a is determined using a reading device having a light source LS and a sensor SS. As shown in FIG. 2, the light source LS and the sensor SS are placed on the support 12 side of the anti-counterfeit medium 10a, and light is emitted from the light source LS obliquely to the surface of the support 12 (FIG. 2 middle thick arrow). The light source LS emits light with a narrow band wavelength having a predetermined center wavelength.
Incident light is preferably incident on the surface of the support 12 from a direction of 30 to 60°.

Here, in the anti-counterfeit medium 10a of the present invention, the haze value of the support 12 is 2% or more, so that the light incident on the support 12 is diffused as shown in FIG. Further, since the visible light transmittance of the support 12 is 30% or more, the diffused light reaches the reflective layer 14. If the central wavelength of light and the selective reflection wavelength of the cholesteric liquid crystal structure of the reflective layer 14 are substantially the same, the light that has reached the reflective layer 14 is reflected. At that time, since the light is diffused, it is incident on the surface of the reflective layer 14 (interface with the support 12) at various angles. Since the reflection of the cholesteric liquid crystal structure of the reflective layer 14 is specular reflection, the light incident on the reflective layer 14 is specularly reflected according to various incident angles. Therefore, the light reflected by the reflective layer 14 travels in various directions. The light reflected by the reflective layer 14 propagates inside the support 12 and is emitted from the surface of the support 12. Further, when the light propagates in the support 12, the light is diffused in the support 12. Therefore, the light emitted from the surface of the support 12 is emitted in various directions. Therefore, at least a part of the light is incident on the sensor SS regardless of the arrangement position of the sensor SS arranged facing the support body 12 side of the forgery prevention medium 10a. This makes it possible to properly read regardless of the position of the sensor when irradiating the anti-counterfeit medium with light to determine the authenticity.

On the other hand, the case where the haze value of the support is less than 2% will be described with reference to FIG.
FIG. 3 is a diagram for explaining the operation when determining the authenticity of the anti-counterfeit medium 100 having the reflective layer 14 having the cholesteric liquid crystal structure on the transparent support 102.
As shown in FIG. 3, the light source LS and the sensor SS are positioned on the support 102 side of the anti-counterfeit medium 100, and light is emitted from the light source LS to the surface of the support 102 obliquely (FIG. 3 middle thick arrow). The light source LS emits light with a narrow band wavelength having a predetermined center wavelength.

Here, in the anti-counterfeit medium 100, since the haze value of the support 102 is less than 2%, the light incident on the support 102 reaches the reflection layer 14 without being diffused, as shown in FIG. If the central wavelength of light and the selective reflection wavelength of the cholesteric liquid crystal structure of the reflective layer 14 are substantially the same, the light that has reached the reflective layer 14 is reflected. At that time, since the light is not diffused, it is incident on the surface of the reflective layer 14 (interface with the support 102) at a constant angle. Since the reflection of the cholesteric liquid crystal structure of the reflective layer 14 is specular reflection, the light incident on the reflective layer 14 is specularly reflected according to the incident angle. Therefore, the light reflected by the reflective layer 14 travels in one direction. The light reflected by the reflective layer 14 propagates inside the support 102 and is emitted from the surface of the support 102. Therefore, the light emitted from the surface of the support 102 is emitted in one direction. Therefore, when the position of the sensor SS arranged facing the support 12 side of the anti-counterfeit medium 10a is not at the position corresponding to the specular reflection on the reflective layer 14, the sensor SS is reflected by the anti-counterfeit medium 100. Light does not enter the sensor SS (the amount of light entering the sensor SS decreases). Therefore, when the authenticity is judged by irradiating the anti-counterfeit medium with light, it cannot be properly read depending on the position of the sensor.

As described above, in the anti-counterfeit medium of the present invention, by setting the haze value of the support 12 to 2% or more, when irradiating light to the anti-counterfeit medium to determine authenticity, regardless of the position of the sensor. , Is properly readable.

From the viewpoint of reading, the haze value of the support 12 is preferably 2% to 40%, more preferably 3% to 20%, further preferably 4% to 15%.
Further, the visible light transmittance of the support 12 is preferably 50% to 95%, more preferably 60% to 93%, further preferably 70% to 90%.
The haze value and the visible light transmittance are the haze value and the transmittance with respect to the visible light, but the haze value and the transmittance with respect to the infrared rays and the ultraviolet rays are similar. Preferably, when the authenticity is determined using infrared rays or ultraviolet rays, it is preferable that the haze value and the transmittance of the support 12 with respect to infrared rays or ultraviolet rays fall within the above numerical ranges.

Here, in the example shown in FIG. 1, the reflective layer 14 is formed uniformly on the entire surface of one surface of the support 12, but the present invention is not limited to this, and the reflective layer 14 is formed in an arbitrary shape on the surface of the support 12. It may have been done. With the configuration in which the reflective layer 14 is formed in an arbitrary shape, the authenticity of the anti-counterfeit medium can be determined based on this shape.

In the example shown in FIG. 1, the uniform reflection layer 14 having the same selective reflection wavelength is provided over the entire surface. However, the present invention is not limited to this, and the reflection layer 14 has a selective reflection wavelength of 30 nm or more due to the cholesteric liquid crystal structure. It may be configured to have two or more different reflection areas.

As an example, the anti-counterfeit medium 10b shown in FIG. 4 has a support 12 and a reflective layer 14b.
The reflective layer 14b has a first reflective area 20a and a second reflective area 20b.
Each of the first reflective region 20a and the second reflective region 20b has a cholesteric liquid crystal structure, and has wavelength selective reflectivity for selectively reflecting light in a wavelength range corresponding to the spiral pitch of each cholesteric liquid crystal structure. ing. The selective reflection wavelength of the first reflection region 20a and the selective reflection wavelength of the second reflection region 20b differ by 30 nm or more. The first reflection area 20a and the second reflection area 20b each have circularly polarized light selective reflectivity.
By thus configuring the reflective layer to have two or more reflective regions, forgery is made based on a combination of wavelength selective reflectivity and circularly polarized light reflectivity in each reflective region, and the shape, arrangement pattern, etc. of each reflective region. The authenticity of the prevention medium can be determined.

When the reflective layer has two or more reflective regions, it is preferable that the selective reflection wavelength of at least one reflective region is a visible light region.
When the reflective layer has two or more reflective regions, it is also preferable to set the selective reflection wavelength of at least one reflective region to the wavelength of the invisible light region.
Further, when the reflective layer has two or more reflective regions, the selective reflection wavelength of at least one reflective region is set to the wavelength of the visible light region, and the selective reflection wavelength of at least one other reflective region is set to It is also preferable to set the wavelength in the invisible light region.

As described above, as anti-counterfeiting technologies, there are the overt technology that enables authenticity verification by visual inspection or a simple tool, and the covert technology that requires the use of dedicated tools for authenticity verification. For example, for banknotes, both obert and covert technologies are used to prevent forgery.
Therefore, an anti-counterfeit medium that is compatible with both the overt technology and the covert technology is desirable.
As a configuration in which the reflective layer has two or more reflective regions, the selective reflection wavelength of at least one reflective region is the wavelength of the visible light region, and the selective reflection wavelength of at least one other reflective region is the wavelength of the invisible light region. By doing so, it is possible to provide a forgery prevention medium that is compatible with both the overt technology and the covert technology.

When the selective reflection wavelength of the reflection area is set to the wavelength of the invisible light area, the selective reflection wavelength is preferably 700 nm or more. The thickness is more preferably 700 nm to 1250 nm (infrared region), and further preferably 800 nm to 1000 nm.
By setting the selective reflection wavelength of the reflection region to 700 nm, the visibility can be reduced and the information can be read only by the covert technique.

Here, the anti-counterfeit medium of the present invention may further have another layer.
For example, like the anti-counterfeit medium 10c shown in FIG. 5, the circular polarizing plate 22 may be provided on the surface side of the reflective layer 14 opposite to the support 12 side.
The circularly polarizing plate 22 is a circularly polarizing plate 22 that absorbs circularly polarized light of the same sense as the circularly polarized light reflected by the cholesteric liquid crystal structure of the reflective layer 14.

As the circularly polarizing plate 22, a conventionally known circularly polarizing plate such as a circularly polarizing plate in which a λ/4 plate and a linear polarizing plate are combined can be appropriately used.

By making the anti-counterfeit medium 10c further include the circularly polarizing plate 22, the light reflected by the reflection layer 14 can be observed from the support 12 side of the anti-counterfeiting medium 10c, and the circularly polarizing plate 22 side. From the above, it is possible to adopt a configuration in which the light reflected by the reflective layer 14 cannot be observed.
This point will be described with reference to FIGS. 6 and 7.

6 and 7 are diagrams for explaining the action of the forgery prevention medium 10c, and FIG. 6 is a diagram for explaining the action when the forgery prevention medium 10c is observed from the support 12 side. FIG. 7 is a diagram for explaining the operation when the forgery prevention medium 10c is observed from the circular polarizing plate 22 side.
6 and 7, the support 12 is not shown for the sake of explanation. Further, the reflective layer 14 and the circularly polarizing plate 22 are shown separated from each other.

In FIGS. 6 and 7, the reflective layer 14 has a reflective region 20 formed in the shape of the alphabet “A”. The reflection area 20 reflects right-handed circularly polarized light.
The circularly polarizing plate 22 is a circularly polarizing plate that absorbs circularly polarized light having the same sense as the circularly polarized light reflected by the reflection region 20, that is, right circularly polarized light in the examples shown in FIGS. 6 and 7. That is, the circularly polarizing plate 22 is a left circularly polarizing plate.

When the anti-counterfeit medium 10c is observed from the support 12 side, as shown in FIG. 6, of the light I ₁ incident on the anti-counterfeit medium 10c from the support 12 side, the right circularly polarized light component I _{1R of the} selective reflection wavelength is obtained. Are reflected by the reflection area 20. Therefore, the shape “A” of the reflection area 20 can be visually recognized. The other right circularly polarized light components are absorbed by the circularly polarizing plate 22, and the left circularly polarized light component I _1L is transmitted through the circularly polarizing plate 22.
Of the light I ₂ that enters the anti-counterfeit medium 10c from the side of the circularly polarizing plate 22, the right circularly polarized light component is absorbed by the circularly polarizing plate 22, and only the left circularly polarized light component I _2L is incident on the reflective layer 14. The left-hand circularly polarized light component I _2L is not reflected by the reflective layer 14 and therefore passes through the reflective layer 14. Therefore, the view (the star in FIG. 6) on the circular polarizer 22 side is visually recognized from the support 12 side.
That is, when the anti-counterfeit medium 10c is observed from the side of the support 12, the anti-counterfeit medium 10c is visually recognized in a state where the shape "A" of the reflection region 20 is superimposed on the scenery on the opposite side of the anti-counterfeit medium 10c.

On the other hand, when the anti-counterfeit medium 10c is observed from the circular polarizing plate 22 side, as shown in FIG. 7, the right circularly polarized light component of I ₂ incident on the anti-counterfeit medium 10c from the circular polarizing plate 22 side is circularly polarized light. Only the left-handed circularly polarized light component I _2L is absorbed by the plate 22 and is incident on the reflective layer 14. The left-hand circularly polarized light component I _2L is not reflected by the reflective layer 14 and therefore passes through the reflective layer 14.
Further, the right circularly polarized light component I _1R of the selective reflection wavelength of the light I ₁ incident on the anti-counterfeit medium 10c from the support 12 side is reflected by the reflection region 20. The other right circularly polarized light components are absorbed by the circularly polarizing plate 22. Only the left circularly polarized light component I _1L passes through the circularly polarizing plate 22. Therefore, only the view (the star in FIG. 7) from the support 12 side to the circularly polarizing plate 22 side is visible.

As described above, by providing the anti-counterfeit medium 10c with the circular polarizing plate 22, the anti-counterfeit medium 10c can observe the light reflected by the reflective layer 14 from the support 12 side. A configuration in which the light reflected by the reflective layer 14 cannot be observed from the polarizing plate 22 side can be adopted.
As a result, the security property (anti-counterfeit property) can be further improved.

In the example shown in FIG. 5, the circular polarization plate 22 is provided on the surface of the reflective layer 14 opposite to the support 12, but the invention is not limited to this, and the forgery prevention medium shown in FIG. A circular polarizing plate 22 may be provided between the support 12 and the reflective layer 14 as in 10d.

With such a configuration, the light reflected by the reflective layer 14 can be visually recognized from the side opposite to the support 12, but the light reflected by the reflective layer 14 cannot be visually viewed from the side of the support 12. You can

Further, in the case of the configuration as shown in FIG. 8, for example, it is assumed that the reflection layer 14 has a reflection region of visible light and a reflection region of invisible light having a selective reflection wavelength, and the circularly polarizing plate 22 has a visible light region. The light may act on the light of (1) and do not act on the light in the invisible light region.
With such a configuration, the light reflected by the reflective layer 14 can be visually recognized from the side opposite to the support 12, but the light reflected by the reflective layer 14 cannot be visually viewed from the side of the support 12. You can On the other hand, when invisible light is emitted from the support 12 side and the reflected light is read by the sensor, the circularly polarizing plate 22 does not function, so the reflected light from the reflective layer 14 can be read.

Further, as in the anti-counterfeit medium 10e shown in FIG. 9 or the anti-counterfeit medium 10f shown in FIG. 10, the overcoat layer 24 may be provided on the surface of the reflective layer 14 opposite to the support. .. The anti-counterfeit medium 10e shown in FIG. 9 has the same structure as the anti-counterfeit medium 10a shown in FIG. 1 except that it has the overcoat layer 24. The counterfeiting prevention medium 10f shown in FIG. 10 has the same structure as the counterfeiting prevention medium 10d shown in FIG. 8 except that it has the overcoat layer 24.
With the structure having the overcoat layer 24, scratch resistance can be improved. In addition, the flatness of the surface of the anti-counterfeit medium can be improved.

The overcoat layer 24 is not particularly limited. For example, a resin layer obtained by coating a composition containing a monomer on the reflection layer 14 and then curing the coating film may be used. The resin is not particularly limited and may be selected in consideration of adhesion to the liquid crystal material forming the reflective layer. For example, a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin or the like can be used. From the viewpoint of durability, solvent resistance, etc., a resin that is curable by crosslinking is preferable, and an ultraviolet curable resin that can be cured in a short time is particularly preferable. Monomers that can be used to form the overcoat layer include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, polymethylolpropane tri(meth)acrylate, and hexanediol (meth). Acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol Di (meth) acrylate etc. are mentioned.

The thickness of the overcoat layer is not particularly limited and may be determined in consideration of scratch resistance, flatness, etc., and may be about 5 μm to 100 μm, preferably 10 μm to 50 μm, more preferably 20 μm to 40 μm. Is.
Further, it may have two or more overcoat layers.

Hereinafter, each element constituting the anti-counterfeit medium of the present invention will be described in detail.

[Reflective layer]
The reflective layer is a layer having a cholesteric liquid crystal structure. The cholesteric liquid crystal structure is a structure in which the orientation of the liquid crystal compound is a cholesteric liquid crystal phase.
Even when the reflective layer has a plurality of reflective regions having different selective reflection wavelengths, the configuration of each reflective region is basically the same as the configuration of the reflective layer described below except that the selective reflection wavelengths are different.

The reflective layer may be a layer in which the orientation of the liquid crystal compound that is in the cholesteric liquid crystal phase is retained, and typically, after the polymerizable liquid crystal compound is in the orientation state of the cholesteric liquid crystal phase, ultraviolet irradiation, Any layer may be used as long as it is polymerized and hardened by heating or the like to form a layer having no fluidity, and at the same time, it is changed to a state in which the orientation form is not changed by an external field or an external force. In the reflective layer, it is sufficient if the optical properties of the cholesteric liquid crystal phase are retained in the layer, and the liquid crystal compound in the layer may no longer exhibit liquid crystallinity. For example, the polymerizable liquid crystal compound may have a high molecular weight due to a curing reaction and may no longer have liquid crystallinity.

It is known that the cholesteric liquid crystal phase exhibits circularly polarized light selective reflection that selectively reflects the circularly polarized light of either the right circularly polarized light or the left circularly polarized light and transmits the circularly polarized light of the other sense.
As a film containing a layer in which a cholesteric liquid crystal phase exhibiting circularly polarized light selective reflection is fixed, many films formed from a composition containing a polymerizable liquid crystal compound have been known in the past. Can refer to technology.

The central wavelength λ of selective reflection of the cholesteric liquid crystal structure depends on the pitch P (=helix period) of the helical structure in the cholesteric liquid crystal phase, and follows the relationship of the average refractive index n of the cholesteric liquid crystal structure and λ=n×P. As can be seen from this equation, the central wavelength of selective reflection can be adjusted by adjusting the n value and the P value.

The selective reflection center wavelength and the half value width of the cholesteric liquid crystal structure can be obtained as follows.
A spectrophotometer (V-670, manufactured by JASCO Corporation) was used to measure the reflection spectrum of the cholesteric liquid crystal structure (reflecting layer) (measured from the normal direction of the reflecting layer). A decline peak is seen. Of the two wavelengths that have an intermediate (average) transmittance between the minimum transmittance of this peak and the transmittance before reduction, the wavelength value on the short wavelength side is λ _l (nm), and the wavelength value on the long wavelength side is Is defined as λ _h (nm), the central wavelength λ of selective reflection and the full width at half maximum Δλ can be expressed by the following equations.
λ=(λ _l +λ _h )/2×Δλ=(λ _h −λ _l )
The central wavelength of the selective reflection obtained as described above substantially coincides with the wavelength at the center of gravity of the reflection peak of the circularly polarized light reflection spectrum measured from the normal direction of the reflection layer.

Since the pitch of the cholesteric liquid crystal phase depends on the type of chiral agent used together with the polymerizable liquid crystal compound or the concentration added, the desired pitch can be obtained by adjusting these. For the method of measuring the sense and pitch of the spiral, use the method described in “Introduction to Liquid Crystal Chemistry” edited by The Liquid Crystal Society of Japan, Sigma Publishing 2007, page 46, and “Liquid Crystal Handbook” Liquid Crystal Handbook Editing Committee Maruzen, page 196. be able to.

As the reflective layer, a reflective layer whose spiral sense is either right or left is used. The sense of the reflected circular polarization of the reflective layer matches the sense of the helix. Further, in the case of a configuration having a plurality of reflection regions, the senses of the spirals in the reflection regions having different central wavelengths of selective reflection may be all the same or different. However, it is preferable that the plurality of reflective regions all have the same twist direction.

The half-value width Δλ (nm) of the selective reflection band showing the selective reflection follows the relationship of Δλ=Δn×P, where Δλ depends on the birefringence Δn of the liquid crystal compound and the pitch P described above. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. The Δn can be adjusted by adjusting the type or mixing ratio of the polymerizable liquid crystal compound, or controlling the temperature when fixing the alignment.
In order to form one kind of reflective layer having the same central wavelength of selective reflection, a plurality of reflective layers having the same pitch P and the same spiral sense may be laminated. By stacking reflective layers having the same pitch P and the same spiral sense, circularly polarized light selectivity can be increased at a specific wavelength.

Further, a plurality of layers having a cholesteric liquid crystal structure having different selective reflection wavelengths may be laminated to form one reflection layer (reflection area).
For example, the wavelength region of reflected light can be widened by sequentially laminating layers with the selective reflection wavelength λ shifted. There is also known a technique of widening a wavelength range by a method called a pitch gradient method for changing a spiral pitch in a layer in a stepwise manner. Specifically, Nature 378, 467-469 (1995), JP-A-6- 2818114 and the method of patent 4990426 are mentioned.
Alternatively, the reflective layer may be configured to reflect the selective reflection wavelengths in each cholesteric liquid crystal structure by providing a plurality of layers of cholesteric liquid crystal structures having different selective reflection wavelengths.

The thickness of the reflective layer is preferably 0.2 to 10 μm, more preferably 0.3 to 8.0 μm, and further preferably 0.4 to 6.0 μm. When the reflective layer has a structure having a plurality of layers having a cholesteric liquid crystal structure, the total thickness is preferably 1.0 to 30 μm, more preferably 1.5 to 25 μm, It is more preferably 2.0 to 20 μm.

In the present invention, the selective reflection wavelength in the reflective layer can be set to any range of visible light (about 380 to 780 nm) and near infrared light (about 780 to 2000 nm), and the setting method is described above. As I did.

Here, the reflective layer having a cholesteric liquid crystal structure is basically for specular reflection of light having a selective reflection wavelength and has low light diffusivity, but may have fluctuation in the direction of the spiral axis of cholesteric alignment, By causing the alignment defect, it is possible to impart light diffusivity to the reflective layer.
Since the reflective layer has diffusibility, the amount of reflected light in a direction other than the direction of specular reflection can be increased.

As a method of imparting light diffusivity to the cholesteric structure of the reflective layer, it is possible to weaken the alignment treatment of the underlying layer when forming the reflective layer, or to adjust the liquid crystal so that it is difficult to align. Specific examples include removing rubbing treatment and using a polyfunctional acrylic resin.

(Method for producing reflective layer)
Hereinafter, a material and a method for manufacturing the reflective layer will be described.
Examples of the material used for forming the above-mentioned reflective layer include a liquid crystal composition containing a polymerizable liquid crystal compound and a chiral agent (optically active compound). If necessary, the liquid crystal composition described above, which is further mixed with a surfactant, a polymerization initiator, or the like and dissolved in a solvent or the like, is applied to a support, an alignment layer, a cholesteric liquid crystal layer as an underlying layer, and the like, after cholesteric alignment aging. The reflective layer can be formed by fixing the liquid crystal composition by curing.

(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound may be a rod-shaped liquid crystal compound or a discotic liquid crystal compound, but is preferably a rod-shaped liquid crystal compound.
An example of the rod-shaped polymerizable liquid crystal compound forming the reflective layer is a rod-shaped nematic liquid crystal compound. Examples of rod-shaped nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines. , Phenyldioxane, tolan, and alkenylcyclohexylbenzonitrile are preferably used. Not only a low molecular weight liquid crystal compound but also a high molecular weight liquid crystal compound can be used.

The polymerizable liquid crystal compound is obtained by introducing a polymerizable group into the liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, an unsaturated polymerizable group is preferable, and an ethylenically unsaturated polymerizable group is particularly preferable. The polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods. The number of polymerizable groups contained in the polymerizable liquid crystal compound is preferably 1 to 6, and more preferably 1 to 4 in one molecule. Examples of the polymerizable liquid crystal compound are described in Makromol. Chem. , 190, 2255 (1989), Advanced Materials, 5 (107) (1993), U.S. Pat. Nos. 4,683,327, 5,622,648, 5,770,107, and WO 95/22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, No. 1-272551, No. 6-16616, No. 7-110469. No. 11-80081, No. 2001-328973, No. 2001-328973, No. 2011-207941, No. 2012-6997, No. 2008-19240, No. 2013-166879. , No. 2014-198814, No. 2014-198815 and the like. You may use together 2 or more types of polymerizable liquid crystal compounds. When two or more kinds of polymerizable liquid crystal compounds are used together, the alignment temperature can be lowered.

Specific examples of the polymerizable liquid crystal compound include compounds represented by the following formulas (1) to (13).

[In the compound (11), X ¹ is 2 to 5 (an integer). ]

(12)

(13)

As the polymerizable liquid crystal compound other than the above, a cyclic organopolysiloxane compound having a cholesteric phase as disclosed in JP-A-57-165480 can be used. Further, as the above-mentioned polymer liquid crystal compound, a polymer in which a mesogenic group exhibiting liquid crystal is introduced in the main chain, a side chain, or both positions of the main chain and a side chain, a polymer in which a cholesteryl group is introduced in a side chain Liquid crystals, liquid crystalline polymers as disclosed in JP-A-9-133810, and liquid crystalline polymers as disclosed in JP-A-11-293252 can be used.

Further, the addition amount of the polymerizable liquid crystal compound in the liquid crystal composition is preferably 80 to 99.9% by mass, and 85 to 99% by mass based on the solid content mass (mass excluding the solvent) of the liquid crystal composition. It is more preferably 0.5% by mass, and particularly preferably 90 to 99% by mass.

The reflective layer may have a low Δn in order to improve the visible light transmittance. The low Δn reflective layer can be formed using a low Δn polymerizable liquid crystal compound. The low Δn polymerizable liquid crystal compound will be specifically described below.

(Low Δn polymerizable liquid crystal compound)
A narrow band reflective layer can be obtained by forming a cholesteric liquid crystal phase using a low Δn polymerizable liquid crystal compound and fixing it to form a film. Examples of low Δn polymerizable liquid crystal compounds include the compounds described in WO2015/115390, WO2015/147243, WO2016/035873, JP-A-2015-163596, and JP-A-2016-53149. The description of WO2016/047648 can also be referred to for the liquid crystal composition which gives a reflective layer having a narrow half width.

It is also preferable that the liquid crystal compound is a polymerizable compound represented by the following formula (I) described in WO2016/047648.

In the formula (I), A represents a phenylene group which may have a substituent or a trans-1,4-cyclohexylene group which may have a substituent, and L represents a single bond, —CH ₂ O-, -OCH ₂ -, -(CH ₂ ) ₂ OC(=O)-, -C(=O)O(CH ₂ ) ₂ -, -C(=O)O-, -OC(=O) Represents a linking group selected from the group consisting of -, -OC(=O)O-, -CH=CH-C(=O)O-, and -OC(=O)-CH=CH-, and m is 3 represents an integer of 3 to 12, and Sp ¹ and Sp ² are each independently a single bond, a linear or branched alkylene group having 1 to 20 carbon atoms, and a linear or branched alkylene group having 1 to 20 carbon atoms. One or more —CH ₂ — is —O—, —S—, —NH—, —N(CH ₃ )—, —C(═O)—, —OC(═O)—, or — Represents a linking group selected from the group consisting of a group substituted with C(═O)O—, wherein Q ¹ and Q ² are each independently a hydrogen atom or a group represented by the following formula Q-1 to formula Q-5. Represents a polymerizable group selected from the group consisting of the following groups, wherein ^one of Q ¹ and Q ² represents a polymerizable group.

The phenylene group in formula (I) is preferably a 1,4-phenylene group.
With respect to the phenylene group and the trans-1,4-cyclohexylene group, the substituent which is “optionally substituted” is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group and an alkyl ether. Examples of the substituent include a group, an amido group, an amino group, a halogen atom, and a substituent selected from the group consisting of a combination of two or more of the above substituents. Moreover, examples of the substituent include a substituent represented by -C(=O)-X ³ -Sp ³ -Q ³ described later. The phenylene group and trans-1,4-cyclohexylene group may have 1 to 4 substituents. When it has two or more substituents, the two or more substituents may be the same or different from each other.

The alkyl group may be linear or branched. The alkyl group preferably has 1 to 30 carbon atoms, more preferably has 1 to 10 carbon atoms, and further preferably has 1 to 6 carbon atoms. Examples of the alkyl group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group. Examples thereof include a group, 1,1-dimethylpropyl group, n-hexyl group, isohexyl group, linear or branched heptyl group, octyl group, nonyl group, decyl group, undecyl group, or dodecyl group. The above description regarding the alkyl group is the same for the alkoxy group containing an alkyl group. Specific examples of the alkylene group when referred to as an alkylene group include a divalent group obtained by removing one arbitrary hydrogen atom from each of the above-mentioned examples of the alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The carbon number of the cycloalkyl group is preferably 3 to 20, more preferably 5 or more, preferably 10 or less, more preferably 8 or less, and further preferably 6 or less. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

As the substituent which the phenylene group and trans-1,4-cyclohexylene group may have, an alkyl group, an alkoxy group, and a group consisting of -C(=O)-X ³ -Sp ³ -Q ³ are particularly preferable. Substituents selected from are preferred. Here, X ³ represents a single bond, —O—, —S—, or —N(Sp ⁴ —Q ⁴ )—, or is a nitrogen atom forming a ring structure with Q ³ and Sp ^3. Show. Sp ³ and Sp ⁴ are each independently one or more of a single bond, a straight-chain or branched alkylene group having 1 to 20 carbon atoms, and a straight-chain or branched alkylene group having 1 to 20 carbon atoms. CH ₂ -is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O-. A connecting group selected from the group consisting of substituted groups is shown.

Q ³ and Q ⁴ are each independently a hydrogen atom, a cycloalkyl group, or one or more —CH ₂ — in the cycloalkyl group are —O—, —S—, —NH—, —N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O-, or a group represented by formula Q-1 to formula Q-5 Represents any polymerizable group selected from the group consisting of:

In the cycloalkyl group, one or more —CH ₂ — is —O—, —S—, —NH—, —N(CH ₃ )—, —C(═O)—, —OC(═O) Specific examples of the group substituted with -or -C(=O)O- include a tetrahydrofuranyl group, a pyrrolidinyl group, an imidazolidinyl group, a pyrazolidinyl group, a piperidyl group, a piperazinyl group, and a morpholinyl group. .. The substitution position is not particularly limited. Of these, a tetrahydrofuranyl group is preferable, and a 2-tetrahydrofuranyl group is particularly preferable.

In the formula (I), L is a single bond, —CH ₂ O—, —OCH ₂ —, —(CH ₂ ) ₂ OC(═O)—, —C(═O)O(CH ₂ ) ₂ —, — C(=O)O-, -OC(=O)-, -OC(=O)O-, -CH=CH-C(=O)O-, and -OC(=O)-CH=CH Represents a linking group selected from the group consisting of: L is preferably -C(=O)O- or -OC(=O)-. The m-1 L's may be the same or different from each other.

Sp ¹ and Sp ² are each independently one or more of a single bond, a linear or branched alkylene group having 1 to 20 carbon atoms, and a linear or branched alkylene group having 1 to 20 carbon atoms. CH ₂ -is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O-. A connecting group selected from the group consisting of substituted groups is shown. Sp ¹ and Sp ² are each independently a carbon atom having a linking group selected from the group consisting of —O—, —OC(═O)—, and —C(═O)O— at both ends. A group selected from the group consisting of a straight chain alkylene group having 1 to 10 carbon atoms, —OC(═O)—, —C(═O)O—, —O—, and a straight chain alkylene group having 1 to 10 carbon atoms. Is preferably a linking group formed by combining 1 or 2 or more, and is preferably a linear alkylene group having 1 to 10 carbon atoms in which —O— is bonded to both ends.

Q ¹ and Q ² each independently represent a hydrogen atom or a polymerizable group selected from the group consisting of the groups represented by the above formulas Q-1 to Q-5, provided that Q ¹ and Q ² are One of them represents a polymerizable group.
As the polymerizable group, an acryloyl group (formula Q-1) or a methacryloyl group (formula Q-2) is preferable.

In the formula (I), m represents an integer of 3 to 12, is preferably an integer of 3 to 9, more preferably an integer of 3 to 7, and further preferably an integer of 3 to 5. ..

The polymerizable compound represented by the formula (I) has at least one optionally substituted phenylene group as A and a optionally substituted trans-1,4-cyclohexylene group. It is preferable to include at least one. The polymerizable compound represented by the formula (I) preferably contains, as A, 1 to 4 trans-1,4-cyclohexylene groups which may have a substituent, and preferably 1 to 3 trans-1 ,4-cyclohexylene groups which may have a substituent. Is more preferable, and it is still more preferable to include 2 or 3. The polymerizable compound represented by the formula (I) preferably contains, as A, at least one phenylene group which may have a substituent, more preferably 1 to 4 and more preferably 1 to 4 It is more preferable to include three, and it is particularly preferable to include two or three.

In the formula (I), when the number obtained by dividing the number of trans-1,4-cyclohexylene groups represented by A by m is mc, it is preferable that 0.1<mc<0.9, and 0 0.3<mc<0.8 is more preferable, and 0.5<mc<0.7 is further preferable. The polymerizable compound represented by the formula (I) in which the liquid crystal composition is 0.5<mc<0.7, and the polymerizable compound represented by the formula (I) in which 0.1<mc<0.3. It is also preferable to include.

Specific examples of the polymerizable compound represented by the formula (I) include the compounds described in paragraphs 0051 to 0058 of WO2016/047648, JP-A-2013-112631, JP-A-2010-70543, The compounds described in Japanese Patent No. 4725516, WO2015/115390, WO2015/147243, WO2016/035873, JP-A-2015-163596, and JP-A-2016-53149 can be exemplified.

(Chiral agent: optically active compound)
The chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. The chiral compound may be selected according to the purpose because the sense of the helix or the helical pitch induced by the compound differs.
The chiral agent is not particularly limited, and known compounds can be used. As an example of the chiral agent, a liquid crystal device handbook (Chapter 3-4-3, TN (twisted nematic), STN (super-twisted nematic) chiral agent, p. 199, Japan Society for the Promotion of Science, 142th Committee, 1989. ), JP-A-2003-287623, JP-A-2002-302487, JP-A-2002-80478, JP-A-2002-80851, JP-A-2010-181852 or JP-A-2014-034581. Are listed.

The chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound containing no asymmetric carbon atom can also be used as the chiral agent. Examples of the axially chiral compound or the planar chiral compound include binaphthyl, helicene, paracyclophane and derivatives thereof. The chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, a repeating unit derived from the polymerizable liquid crystal compound and a chiral agent are generated by a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound. Polymers having repeating units can be formed. In this aspect, the polymerizable group contained in the polymerizable chiral agent is preferably the same type of group as the polymerizable group contained in the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred.
Further, the chiral agent may be a liquid crystal compound.

As the chiral agent, an isosorbide derivative, an isomannide derivative, or a binaphthyl derivative can be preferably used. As the isosorbide derivative, a commercially available product such as LC756 manufactured by BASF may be used.
The content of the chiral agent in the liquid crystal composition is preferably 0.01 mol% to 200 mol% of the amount of the polymerizable liquid crystal compound, and more preferably 1 mol% to 30 mol %.

(Polymerization initiator)
The liquid crystal composition preferably contains a polymerization initiator. In the embodiment in which the polymerization reaction proceeds by irradiation with ultraviolet rays, the polymerization initiator used is preferably a photopolymerization initiator capable of initiating the polymerization reaction by irradiation with ultraviolet rays. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. No. 2,376,661 and US Pat. No. 2,367,670), acyloin ethers (US Pat. No. 2,448,828), and α-hydrocarbons. Of substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. No. 3,046,127, US Pat. No. 2,951,758), triarylimidazole dimer and p-aminophenyl ketone Combinations (described in US Pat. No. 3,549,367), acridine and phenazine compounds (described in JP-A-60-105667, US Pat. No. 4,239,850), acylphosphine oxide compounds (JP-B-63-40799), JP-B-5-29234, JP-A-10-95788, JP-A-10-29997, JP-A-2001-233842, JP-A-2000-80068, JP-A-2006-342166, and JP-A-2006-342166. 2013-114249, JP-A-2014-137466, JP-A-4223071, JP-A-2010-262028, JP-A-2014-500852, and oxime compound (JP-A-2000-66385, JP Patent) No. 4454067), and oxadiazole compounds (described in US Pat. No. 4,212,970). For example, the description in paragraphs 0500 to 0547 of JP 2012-208494 A can be referred to.

It is also preferable to use an acylphosphine oxide compound or an oxime compound as the polymerization initiator.
As the acylphosphine oxide compound, for example, a commercially available product, IRGACURE 810 (compound name: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) manufactured by BASF Japan Ltd. can be used. As the oxime compound, IRGACURE OXE01 (manufactured by BASF), IRGACURE OXE02 (manufactured by BASF), TR-PBG-304 (manufactured by Changzhou Power Electronics Co., Ltd.), ADEKA ARKRUZ NCI-831, ADEKA ARKRUZ NCI-930 Commercial products such as (made by ADEKA) and ADEKA ARKUL'S NCI-831 (made by ADEKA) can be used.
The polymerization initiator may be used alone or in combination of two or more.
The content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1% by mass to 20% by mass, and more preferably 0.5% by mass to 5% by mass, with respect to the content of the polymerizable liquid crystal compound. Is more preferable.

(Crosslinking agent)
The liquid crystal composition may optionally contain a crosslinking agent in order to improve the film strength after curing and the durability. As the cross-linking agent, one that can be cured by ultraviolet rays, heat, moisture or the like can be preferably used.
The cross-linking agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyfunctional acrylate compounds such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; glycidyl (meth). Epoxy compounds such as acrylate and ethylene glycol diglycidyl ether; 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and aziridine compounds such as 4,4-bis(ethyleneiminocarbonylamino)diphenylmethane; Isocyanate compounds such as hexamethylene diisocyanate and biuret type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; alkoxysilane compounds such as vinyltrimethoxysilane and N-(2-aminoethyl)3-aminopropyltrimethoxysilane Can be mentioned. Further, a known catalyst can be used depending on the reactivity of the cross-linking agent, and the productivity can be improved in addition to the improvement of the film strength and durability. These may be used alone or in combination of two or more.
The content of the crosslinking agent is preferably 3% by mass to 20% by mass, more preferably 5% by mass to 15% by mass. By setting the content of the cross-linking agent to 3% by mass or more, the effect of improving the cross-linking density can be obtained, and by setting the content of the cross-linking agent to 20% by mass or less, deterioration of the stability of the reflective layer is prevented. it can.

(Orientation control agent)
The liquid crystal composition may contain an alignment control agent that contributes to the stable or rapid formation of a reflective layer having a planar alignment. Examples of the orientation control agent include fluorine (meth)acrylate polymers described in paragraphs [0018] to [0043] of JP2007-272185A, and paragraphs [0031] to [0034] of JP2012-203237A. ] And the like, compounds represented by formulas (I) to (IV), compounds described in JP-A-2013-113913, and the like.
As the orientation control agent, one kind may be used alone, or two or more kinds may be used in combination.

The addition amount of the orientation control agent in the liquid crystal composition is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass, based on the total mass of the polymerizable liquid crystal compound. It is particularly preferably from 0.02% by mass to 1% by mass.

(Other additives)
In addition, the liquid crystal composition may contain at least one selected from various additives such as a surfactant for adjusting the surface tension of the coating film to make the thickness uniform and a polymerizable monomer. Further, in the liquid crystal composition, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a coloring material, and metal oxide fine particles may be added, if necessary, within a range not deteriorating the optical performance. Can be added at.

The reflective layer is a support, an alignment layer, or a liquid crystal composition prepared by dissolving a polymerizable liquid crystal compound, a polymerization initiator, a chiral agent, a surfactant, and the like, which are added as necessary, in a solvent. A cholesteric liquid crystal structure in which the cholesteric regularity is fixed by polymerizing the cholesteric liquid crystalline composition by irradiating the coating film with an actinic ray by applying an active ray to the cholesteric liquid crystal layer. It is possible to form a reflective layer having the same.

(solvent)
The solvent used for preparing the liquid crystal composition is not particularly limited and may be appropriately selected depending on the intended purpose, but organic solvents are preferably used.
The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, and ethers. And the like. These may be used alone or in combination of two or more. Among these, ketones are particularly preferable in consideration of the load on the environment.

(Coating, orientation, polymerization)
Support, alignment layer, the coating method of the liquid crystal composition to the cholesteric liquid crystal layer to be the lower layer, etc. is not particularly limited and can be appropriately selected depending on the purpose, for example, a wire bar coating method, a curtain coating method, Examples thereof include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, a spin coating method, a dip coating method, a spray coating method, and a slide coating method. It can also be carried out by transferring a liquid crystal composition separately applied on a support. By heating the applied liquid crystal composition, the liquid crystal molecules are aligned. The heating temperature is preferably 200°C or lower, more preferably 130°C or lower. By this alignment treatment, a reflective layer in which the polymerizable liquid crystal compound is twisted and aligned so as to have a spiral axis in a direction substantially perpendicular to the film surface is obtained.

The liquid crystal composition can be cured by further polymerizing the aligned liquid crystal compound. The polymerization may be either thermal polymerization or photopolymerization utilizing light irradiation, but photopolymerization is preferred. It is preferable to use ultraviolet rays for the light irradiation. The irradiation energy is preferably ^{20mJ / cm 2 ~ 50J / cm} 2, 100mJ / cm 2 ~ 1,500mJ / cm 2 is more preferable.
To accelerate the photopolymerization reaction, light irradiation may be carried out under heating or under a nitrogen atmosphere. The irradiation ultraviolet wavelength is preferably 350 to 430 nm. From the viewpoint of stability, the polymerization reaction rate is preferably high, preferably 70% or more, and more preferably 80% or more. The polymerization reaction rate can be determined by measuring the consumption rate of the polymerizable functional group by measuring the infrared absorption spectrum.

In the case where the reflective layer has two or more reflective regions having different selective reflection wavelengths, each reflective region is formed on the temporary support by the above-mentioned method, and each produced reflective region is cut into a desired shape. For example, it may be produced by transferring it onto a support.
Alternatively, for example, by printing by an inkjet printing method, a gravure printing method, a flexo printing method, or the like, a coating layer having a desired shape is formed on a support, and then an exposure treatment, a heat treatment, and a curing treatment are performed to obtain a desired shape. The reflective layer having two or more reflective regions may be produced by repeating the formation of the reflective regions.
Alternatively, as the chiral agent, a photosensitive chiral agent which is sensitive to light and can change the helical pitch of the cholesteric liquid crystal phase may be used. Specifically, after applying the liquid crystal composition to the support, the photosensitive chiral agent is irradiated with light having a wavelength to be exposed through a mask having a predetermined opening pattern corresponding to the shape of each reflective region. The selective reflection wavelength may be different for each reflection region by changing the helical induction force (HTP: Helical Twisting Power) of the chiral agent.

[Support]
The support supports the reflective layer 14. In the present invention, the support 12 has a haze value of 2% or more and a visible light transmittance of 30% or more.
The support 12 may be a single layer member or a member formed by laminating a plurality of layers. In the case of a support in which a plurality of layers are laminated, it is sufficient that the haze value of the whole support is 2% or more and the visible light transmittance is 30% or more.

As an example of the support on which a plurality of layers are laminated, a structure having a base material 16 and an intermediate layer 18 as illustrated in FIG. 1 is illustrated.
In the case of the structure having the base material 16 and the intermediate layer 18, the base material 16 ensures the strength capable of supporting the reflective layer 14, and the intermediate layer 18 has a scattering function of having a haze value of 2% or more. It is preferable that the layer has.

(Base material)
As the base material, various resin films used as the base material in the optical film can be used.
Examples of the material of the base material include polyolefin resins such as polypropylene, polyacrylic resins such as polymethylmethacrylate, cellulose resins such as cellulose triacetate, cycloolefin polymer resins, polyethylene terephthalate (PET), polycarbonate, and polychlorinated resins. Examples thereof include vinyl. The material of the base material is not limited to resin, and glass may be used.

The front phase difference of the base material is preferably 400 nm or less, more preferably 200 nm or less, and further preferably 122 nm or less. This is preferable in that it is possible to reduce the influence of polarization conversion by the support when making an authenticity determination using polarized light.

There is no limitation on the thickness of the base material, and the thickness capable of holding the reflective layer may be appropriately set depending on the use of the anti-counterfeit medium, the material forming the base material, and the like.
The thickness of the substrate is preferably from 1 to 1000 μm, more preferably from 3 to 250 μm, even more preferably from 5 to 150 μm.

(Middle layer)
When the intermediate layer is a layer having a scattering function with a haze value of 2% or more, it may be a layer made of a resin having a high haze value or a resin layer containing fine particles as a scattering material. ..

As the resin having a high haze value, polypropylene, polycarbonate, polyester such as polyethylene terephthalate, polyvinyl chloride, polyamide and the like can be used.

The fine particles may be fine particles having a refractive index different from that of the resin to be dispersed, and known scattering materials can be used. As the fine particles, for example, acrylic particles, silicone particles, nylon particles, styrene particles, polyethylene particles, urethane particles, resin particles such as benzoguanamine, or inorganic particles such as alumina particles and silica particles can be used.

The type of fine particles, the particle size and the addition amount may be appropriately selected according to the dispersibility in the resin to be dispersed, the solubility, the refractive index, the thickness of the support, the haze value as the support, the visible light transmittance, and the like. Good.
From the viewpoint of scattering properties, the particle size of the fine particles is preferably 50 nm or more, more preferably 100 nm to 200 nm, further preferably 150 nm to 1000 nm.

Further, the resin for dispersing the fine particles is not particularly limited as long as the haze value and the visible light transmittance as the support satisfy the above ranges. For example, polyacrylate resin such as polyfunctional acrylate or urethane acrylate can be used.

Further, the intermediate layer may have a function as an adhesive layer. When the intermediate layer has a bonding function, the reflective layer and the support can be bonded to each other when the reflective layer is formed by transfer.
When the intermediate layer is used as the adhesive layer, acrylic resin, epoxy resin, or the like can be used.
Further, when the intermediate layer has a function as an adhesive layer, the fine particles described above may be dispersed.

As a single-layer support having a haze value and a visible light transmittance satisfying the above ranges, a resin film made of a polyolefin resin such as polypropylene is exemplified.
In addition, a dispersion of the above-mentioned fine particles in the above-mentioned material as a material of the base material may be used as a single-layer support, and the haze value and visible light transmittance of the support may satisfy the above ranges.

(Other layers)
The anti-counterfeit medium may have a layer other than the above-mentioned support (base material and intermediate layer), reflective layer, and circularly polarizing plate.
For example, an adhesive layer for laminating each layer may be provided between each layer constituting the anti-counterfeit medium.
Further, an adhesive layer may be provided on the outermost surface layer of either one of the anti-counterfeit media. By providing the adhesive layer on the outermost layer, the anti-counterfeit medium can be attached to various articles for use. When the outermost layer has an adhesive layer, a peelable protective film may be provided on the adhesive layer. When the anti-counterfeit medium is attached to the article, the protective film is peeled off to attach the anti-counterfeit medium to the article, whereby the adhesive force of the adhesive layer can be prevented from being lowered.

(Adhesive layer)
As the adhesive layer, as long as the target layer (sheet-like material) can be bonded, those made of various known materials can be used, and when it is bonded, it has fluidity and then solid. , A layer made of an adhesive, or a soft gel-like (rubber-like) solid at the time of bonding, which does not change the gel state thereafter, may be a layer made of an adhesive, or an adhesive and an adhesive layer. It may be a layer made of a material having both characteristics as an agent. Therefore, as the adhesive layer, an optical transparent adhesive (OCA (Optical Clear Adhesive)), an optical transparent double-sided tape, an ultraviolet curable resin, or the like known in the art for bonding sheet-like materials may be used.

<Information card>
The information card of the present invention is
The anti-counterfeiting medium described above,
An information card having an image printing unit.

In the present invention, the information card is used in banknotes, securities, tickets, passports, driver's licenses, my number cards, ID (IDentification) cards such as admission cards, credit cards, cash cards, prepaid cards, stamps, local governments, etc. It includes the certificate of income used, stamps for postage, certificate of seal, certificate of residence used for certificate of residence, brand certificate, certificate of authenticity such as pharmaceutical products, etc.

The information card has an image printing unit on which characters, symbols, pictures, etc. are printed according to the type of the information card, and the above-mentioned forgery prevention medium. In this information card, the authenticity of the information card can be determined by using an anti-counterfeit medium.
As described above, since the anti-counterfeit medium of the present invention has high security (anti-counterfeit property), it is difficult to forge an information card having the anti-counterfeit medium of the present invention, and the security can be enhanced.

Here, it is preferable that the anti-counterfeit medium 10 and the image printing section 32 are covered with the same overcoat layer 24 as in the information card 30 shown in FIG. 11. That is, the overcoat layer of the anti-counterfeit medium and the overcoat layer of the image printing section may be integrally formed.
Further, in FIG. 11, the support 12 is formed integrally with the support of the image printing unit 32.
In FIG. 11, the area surrounded by the broken line corresponds to the forgery prevention medium 10.

The anti-counterfeit medium and the image printing part are covered with the same overcoat layer, so that scratch resistance can be improved. In addition, the flatness of the surface of the information card can be improved.

In addition, by arranging the anti-counterfeit medium in a desired pattern on the surface of the information card, it is possible to judge the authenticity based on the arrangement pattern of the anti-counterfeit medium.

Although the forgery prevention medium and the information card of the present invention have been described above in detail, the present invention is not limited to the above-mentioned examples, and various improvements and changes may be made without departing from the scope of the present invention. Of course.

The features of the present invention will be described more specifically with reference to the following examples. The materials, reagents, usage amounts, substance amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following specific examples.

[Example 1]
As Example 1, an anti-counterfeit medium 10b having a structure as shown in FIG. 4 was produced.

(Preparation of liquid crystal composition)
The composition shown below was stirred and dissolved in a container kept at 25° C. to prepare a cholesteric liquid crystal coating liquid A1.
－－－－－－－－－－－－－－－－－－－－－－－－－－－－
Cholesteric liquid crystal coating liquid A
－－－－－－－－－－－－－－－－－－－－－－－－－－－－
84 parts by mass of the following liquid crystal compound M-1 14 parts by mass of the following liquid crystal compound M-2 2 parts by mass of the following liquid crystal compound M-3 1 part by mass of the chiral agent 1 having the following structure Horizontal of the following structure Orientation agent 1 0.05 parts by mass-Initiator: IRGACURE 907 (manufactured by BASF) 4 parts by mass-IRGANOX 1010 1 part by mass-MEK (methyl ethyl ketone) 180 parts by mass --------------- －－－－－－－－－－－－－－－－

Compound M-1 (structure below)

Compound M-2 (structure below)

Compound M-3 (structure below)

(Formation of cholesteric liquid crystal layer)
As a temporary support, a PET (polyethylene terephthalate, Cosmoshine A4100) film manufactured by Toyobo Co., Ltd. having a thickness of 100 μm was used. After the PET film was rubbed, the cholesteric liquid crystal coating liquid A prepared above was temporarily used. The rubbing surface on the support was coated with a wire bar. The coating amount was adjusted so that the thickness of the coating layer after drying was about 4.5 μm. The coating was performed at room temperature.
Next, the coating layer is irradiated with UV (ultraviolet) for a certain period of time through a black mask having a predetermined opening pattern in an oxygen atmosphere at room temperature, and then the mask is removed and UV irradiation is performed for a certain period of time. The pitch of the structure was adjusted. The exposure amount of the portion without the mask was 50 mJ/cm ² , and the exposure amount of the portion with the mask was 15 mJ/cm ² .

Next, the temporary support on which the coating layer after UV irradiation was laminated was allowed to stand on a hot plate at 100° C. for 1 minute to perform heat treatment.
Next, in a nitrogen atmosphere (oxygen concentration of 500 ppm or less), at room temperature, the coating layer after the heat treatment is irradiated with UV for a certain period of time to cure the coating layer to have two or more types of reflective regions having different selective reflection wavelengths. The reflective layer R1 was formed. The UV irradiation dose in this step was 500 mJ/cm ² . The formed reflective layer R1 has a right-handed cholesteric liquid crystal phase and reflects right-handed circularly polarized light.
In this example, in the step of curing the reflective layer as a light source for UV irradiation, “EXECURE 3000-W” (manufactured by HOYA CANDEO OPTRONICS Co., Ltd.) was used to adjust the pitch of the helical structure in the cholesteric liquid crystal phase. In the process, UV transilluminator LM-26 type (manufactured by Funakoshi Co., Ltd.) was used.

(Transfer of reflective layer)
One side of a polypropylene film (2500H, manufactured by Toray Industries, Inc.) as a substrate was corona-treated, and the acrylic solution Z1 shown below was applied to the surface so that the film thickness after drying was 2 μm. The coated surface and the reflection layer R1 produced above were attached to each other so that air bubbles did not enter, and UV was irradiated using "EXECURE 3000-W" (manufactured by HOYA CANDEO OPTRONICS CO., LTD.) to give an acrylic solution Z1. The intermediate layer (adhesive layer) Z1 was formed by curing. The irradiation dose at this time was 300 mJ/cm ² . After that, the PET film as the temporary support was peeled off from the reflective layer R1 to obtain the forgery prevention medium G1 of Example 1.
In the anti-counterfeit medium G1, the base material (polypropylene film) and the intermediate layer Z1 were the support B1, and the haze value of this support B1 was 5%. The visible light transmittance was 91%.

(Composition of acrylic solution Z1)
・Vanaresin GH-1203 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts by mass ・Viscoat #360 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 50 parts by mass ・Silica particle dispersion (manufactured by Nissan Chemical Co., AC- 5140Z, solid content 30 wt%) 24 parts by mass ・IRGACURE819 (manufactured by BASF) 4 parts by mass ・Horizontal aligning agent 1 0.01 parts by mass In addition, MEK/MIBK (methyl isobutyl) is used so that the solid content becomes 30 wt% (Ketone) (1/1 wt%).

(Visual evaluation of anti-counterfeit medium)
The reflection layer R1 of the anti-counterfeit medium G1 manufactured in Example 1 has two reflection regions having different selective reflection wavelengths. The selective reflection wavelength in the masked region when producing the reflective layer R1 is in the visible light region of 450 nm to 650 nm, and the selective reflection wavelength in the region without the mask is in the near infrared region of 800 nm or more. When the anti-counterfeit medium G1 was visually checked, the masked area could be visually recognized as a pattern of characters and images.
Further, when the anti-counterfeit medium G1 was observed through the left circularly polarizing plate with the reflection layer R1 on the front side, the pattern of the reflection area could not be recognized. It was confirmed that the authenticity can be judged by a simple method.

(Equipment evaluation of anti-counterfeit media)
The anti-counterfeit medium G1 of Example 1 was set in the absolute reflectance measurement unit ARV474S type connected to the JASCO spectrophotometer V-670 so that the support B1 side faced the light source. The incident light was set to 45 degrees with respect to the surface of the anti-counterfeiting medium G1 on the support B1 side, and the sensor (detector) was set to be in the vertical direction with respect to the surface of the anti-counterfeiting medium G1 on the support B1 side (that is, a scanner was simulated. Diffuse reflectance of the anti-counterfeit medium G1 was measured using a format in which reflected light from obliquely incident light is detected in the front direction.
The diffuse reflectance was similarly measured for the support B1 alone, that is, for the laminate having the same configuration as the forgery prevention medium G1 except that the support B1 was not provided, and the result was used as a reference. When the detection intensity of the reference was 1, the relative detection intensity of the forgery prevention medium G1 of Example 1 was 1.8.

[Comparative Example 1]
In Comparative Example 1, a reflective film R1 was formed on the PET film that is the temporary support in Example 1. In other words, the anti-counterfeit medium of Comparative Example 1 has the same structure as the anti-counterfeit medium of Example 1 except that the support B1 was changed to a PET film.
The haze value of the PET film was 0.4%. The visible light transmittance was 92%.

(Equipment evaluation of anti-counterfeit media)
In the same manner as in Example 1, the diffuse reflectance of the anti-counterfeit medium of Comparative Example 1 was measured. Also, the diffuse reflectance was measured in the same manner for the support alone, that is, for the PET film alone, and the result was used as a reference. When the detection intensity of the reference is 1, the relative detection intensity of the anti-counterfeit medium of Comparative Example 1 was 1.

From the above results, the anti-counterfeit medium G1 which is an example of the present invention having the support B1 having a high haze value has a significantly higher detection strength than the support B1 alone, and thus is useful as an anti-counterfeit medium. I understand. On the other hand, in Comparative Example 1 having a support having a low haze, it can be seen that it cannot be used as a forgery prevention medium because the detection strength is the same as that of the support alone. That is, it can be seen that the light reflected by the reflective layer R1 cannot be detected in Comparative Example 1, whereas the light reflected by the reflective layer R1 can be detected in Example 1.

[Example 2]
An anti-counterfeit medium G2 was produced in the same manner as in Example 1 except that the overcoat layer Z2 was formed on the surface of the reflective layer R1 opposite to the support B1.
Specifically, the following acrylic solution Z2 was applied on a PET film as a temporary support so that the film thickness after drying was 2 μm, and heat treatment was performed at 85° C., and then “2” was applied under a nitrogen atmosphere. Execure 3000-W" (manufactured by HOYA CANDEO OPTRONICS CO., LTD.) was used to irradiate UV to form the overcoat layer Z2. The irradiation dose at this time was 150 mJ/cm ² .
Using the PET film with the overcoat layer Z2 as a temporary support, the reflective layer R2 was formed on the overcoat layer Z2 in the same manner as in Example 1, and the reflective layer R2 and the overcoat layer Z2 were used as the support B1. The image was transferred to manufacture an anti-counterfeit medium G2.
Although the reflective layer R2 was manufactured by the same method as the reflective layer R1, the underlying layer is different, so that the reflective layer R2 has a different structure from the reflective layer R1 and has a different reflective property. Specifically, when the overcoat layer Z2 is used as a base layer, the spiral axis of the cholesteric liquid crystal phase fluctuates and many alignment defects occur, so that the diffusivity of the reflective layer R2 itself becomes higher than that of the reflective layer R1.

(Composition of acrylic solution Z2)
-Biscoat #360 (Osaka Organic Chemical Industry Co., Ltd.) 100 parts by mass-IRGACURE819 (BASF Corp.) 4 parts by mass-Horizontal aligning agent 1 0.01 parts by mass-MEK 200 parts by mass

(Visual evaluation of anti-counterfeit medium)
When the anti-counterfeit medium G2 was visually confirmed, the pattern of the reflection region was visually recognized in a wider area than G1.
When the anti-counterfeit medium G2 was observed through the right circularly polarizing plate with the overcoat layer Z2 side on the front side, the pattern of the reflection area could not be recognized.

(Equipment evaluation of anti-counterfeit media)
In the same manner as in Example 1, the diffuse reflectance of the anti-counterfeit medium G2 of Example 2 was measured. The reference is the support B1. The relative detection intensity of the anti-counterfeit medium G2 of Example 2 was 2.6.

[Example 3]
An anti-counterfeit medium G3 having the same configuration as in Example 1 was produced except that the circularly polarizing plate was provided on the reflective layer R1.
The circularly polarizing plate is a left circularly polarizing plate, and includes a λ/4 plate (MCR140N: manufactured by Mitate Imaging Co., Ltd.) and a linear polarizing plate (MCR140N: manufactured by Mitate Imaging Co., Ltd.) as an adhesive layer (MCS70: Mitate Imaging Inc.). (Manufactured), and the direction was adjusted, and it stuck and produced.
The λ/4 plate side of this circularly polarizing plate was laminated on the reflection layer R1 by using an adhesive layer (MCS70: manufactured by Meitan Imaging Co., Ltd.).

(Visual evaluation of anti-counterfeit medium)
When the anti-counterfeit medium G3 is visually checked, the pattern of the reflection area can be recognized when observed from the support B1 side, whereas the pattern of the reflection area is observed when observed from the side opposite to the support B1 (circular polarizing plate side). However, it became transparent, and the anti-counterfeiting performance could be visually confirmed.

(Equipment evaluation of anti-counterfeit media)
In the same manner as in Example 1, the diffuse reflectance of the anti-counterfeit medium G3 of Example 3 was measured. The reference is the support B1. The relative detection intensity of the forgery preventing medium G3 of Example 3 was 1.8.

[Example 4]
An anti-counterfeit medium G4 having the same configuration as in Example 2 was produced except that a circularly polarizing plate was provided between the support B1 and the reflective layer R2.
As the circularly polarizing plate, the same circularly polarizing plate as that of Example 3 was used.
After forming the reflective layer R1 on the temporary support (PET film with the overcoat layer Z2), the λ/4 plate side of the circularly polarizing plate is provided on the reflective layer R1 with an adhesive layer (MCS70: manufactured by Mitachi Imaging Co., Ltd.). ) Was used for bonding. Next, the overcoat layer Z2, the reflective layer R1, and the circularly polarizing plate were transferred to the support B1 to prepare an anti-counterfeit medium G4.

(Visual evaluation of anti-counterfeit medium)
When the anti-counterfeit medium G4 was visually confirmed, the pattern of the reflection area was recognizable when observed from the side opposite to the support B1 (the overcoat layer Z2 side), whereas when observed from the support B1 side, The pattern could not be recognized and became transparent, and the anti-counterfeiting performance could be visually confirmed.

(Equipment evaluation of anti-counterfeit media)
In the same manner as in Example 1, the diffuse reflectance of the forgery prevention medium G4 of Example 4 was measured. The reference is the support B1. The relative detection intensity in the visible light region was 1.1. The relative detection intensity in the near infrared region was 2.5.
This is because right circularly polarized light does not reach the reflective layer R2 due to the action of the circularly polarizing plate in the visible light region, and thus the reflected light component by the reflective layer R2 is hardly detected. On the other hand, since the circularly polarizing plate does not function in the near infrared region, the right circularly polarized light reaches the reflection layer R2 and is reflected by the reflection layer R2, so that the light reflected by the reflection layer R2 is detected. is there.
Therefore, it can be seen that in reading using light in the near infrared region, a pattern that is reversed from the visual observation is detected.
From the above results, the effect of the present invention is clear.

10, 10a to 10f Anti-counterfeit medium 12

Support

14, 14b Reflective layer 16 Base material 18 Intermediate layer 20 Reflective area 20a First reflective area 20b Second reflective area 22 Circular polarizing plate 24 Overcoat layer 30 Information card 32 Image printing section

Claims

A reflective layer and a support that supports the reflective layer,
The reflective layer has a cholesteric liquid crystal structure,
An anti-counterfeit medium in which the haze value of the support is 2% or more and the visible light transmittance is 30% or more.
The anti-counterfeit medium according to claim 1, wherein the reflective layer has two or more reflective regions having selective reflection wavelengths different by 30 nm or more due to the cholesteric liquid crystal structure.
The anti-counterfeit medium according to claim 2, wherein the selective reflection wavelength of at least one of the reflection regions is a wavelength in the visible light region.
The anti-counterfeit medium according to claim 2 or 3, wherein the selective reflection wavelength of at least one of the reflection areas is a wavelength of an invisible light area.
The anti-counterfeit medium according to claim 4, wherein the selective reflection wavelength of at least one of the reflection regions is 700 nm or more.
The anti-counterfeit medium according to any one of claims 2 to 5, which has two or more reflection areas arranged at different positions in a plane.
The anti-counterfeit medium according to any one of claims 1 to 6, further comprising a circularly polarizing plate that absorbs circularly polarized light having the same sense as circularly polarized light reflected by the cholesteric liquid crystal structure of the reflective layer.
The anti-counterfeit medium according to any one of claims 1 to 7, wherein the support has a base material and an intermediate layer.
The anti-counterfeit medium according to claim 8, wherein the intermediate layer contains fine particles having a particle size of 50 nm or more.
The anti-counterfeit medium according to claim 8 or 9, wherein the base material is made of a polyolefin-based polymer material.
The anti-counterfeit medium according to any one of claims 8 to 10, wherein the front phase difference of the base material is 400 nm or less.
The anti-counterfeit medium according to any one of claims 1 to 11, which has an overcoat layer on a side of the reflective layer opposite to the support side.
An anti-counterfeit medium according to any one of claims 1 to 12,
An information card having an image printing section.
The information card according to claim 13, wherein the anti-counterfeit medium and the image printing section are covered with the same overcoat layer.